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                                 OVERVIEW
     The publication consists of two guidance documents designed to be
used in tandem:  The RCRA Ground-Water Monitoring Compliance Order
Guidance and the Draft RCRA Ground-Water Monitoring Technical Enforcement
Guidance Document.  Together these two documents provide comprehensive
guidance on how to identify and rectify ground-water monitoring violations
at RCRA hazardous waste facilities.  Both documents should be read by all
individuals involved in addressing RCRA ground-water monitoring problems
including regional and state enforcement officials, permit writers, field
inspectors, and attorneys.
     The Draft RCRA Ground-Water Monitoring Technical Enforcement
Guidance Document (TEGD), provides draft guidance on how to evaluate the
technical adequacy of a facility's interim status monitoring system.  The
document discusses each of the elements that is important to the overall
adequacy of an owner/operator's monitoring system and, where possible,
makes specific judgements on what activities and methodologies are
appropriate to meet the terms of the regulations.  Specifically, the TEGD
provides guidance on how to evaluate:
     •  the owner/operator's hydrogeologic characterization of the
        facility;
     •  the adequacy of the number and location of ground-water
        monitoring wells;
     •  the design and construction of the monitoring wells;
     •  the sampling and analysis plan;
     •  the statistical analysis of the monitoring data; and
     •  the owner/operator's assessment plan.
                                              U.S.  EnvijiQRiMntal  Protection Agency
                                              Regi.n 5,  L^r^y  (5PL-16)
                                              230 S.  Dearty^ fit -eet, Room 1670
                                              Chicago,  H   '

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Enforcement officials should consider the guidance in the TEGD to help
determine whether an existing monitoring system is in compliance with
the regulations.  In addition, enforcement officials should consider the
recommendations contained in the TEGD when directing respondents to
undertake ground-water activities pursuant to an enforcement order.
     The RCRA Ground-Water Monitoring Compliance Order Guidance, (COG)
presents the Agency's strategy for correction of ground-water problems at
interim status land disposal facilities.  The cornerstone of this
strategy is the issuance of orders that correct existing interim status
ground-water violations in a manner consistent with the needs of the RCRA
permitting program.  The guidance encourages the development of technical
ground-water remedies that integrate the facility's interim status
monitoring obligations (Part 265) with the requirements mandated by the
permit application regulations (Part 210).  By integrating the two sets
of regulations, the Agency hopes to speed the issuance of operating and
post-closure permits, thereby bringing the regulated community under the
stricter requirements of Part 264 as quickly as possible.

                          HOW TO USB THIS MANUAL
     The Compliance Order Guidance and the Draft Technical Enforcement
Guidance Document have been bound together in order to emphasize that the
documents should be used jointly.  The COG should be read first because
this document introduces the Agency's approach to ground-water compliance
and provides important background information on the interrelationship of
the Part 265, Part 270, and Part 264 ground-water regulations.  Even
individuals more interested in the technical aspects of a facility's
ground-water monitoring program will benefit from the regulatory back-
ground and policy context provided by this document.  Next, regional and
state personnel should read the TEGD.  The TEGD provides draft technical
information to evaluate existing systems and develop the type of highly
specific orders encouraged by the COG.  As with the COG, even those
C
                                    -2-

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individuals not directly involved in the technical aspects of ground-
water monitoring will benefit from familiarity with the criteria and
information that technical staff use to design and evaluate ground-water
programs.

                 COORDINATION IN THE ENFORCEMENT PROCESS
     The implementation of this guidance will require the coordinated
effort of many actors with different technical, policy, and legal exper-
tise.  Technical enforcement staff (e.g., hydrogeologists, statisticians),
permit writers, field inspectors, and enforcement attorneys will all have
to work together to achieve the comprehensive remedies and detailed orders
envisioned by the COG.  The TEGD and the COG were designed to facilitate
and inform this group effort.
     The coordination between actors begins before the field inspector
conducts the site visit.  Prior to the site visit, the technical
enforcement staff member should gather and review all information
available about the facility including, among other documents, the
facility's Part A and Part B permit applications, previous inspection
reports, and existing facility records.  Next, the enforcement staff
person and the field inspector should meet to develop a plan of action
for the inspection.  Having performed an initial evaluation of the
facility, the technical staff person should be able to provide guidance
to the field inspector on what further information to collect and what
potential problems should be investigated during the site visit.
(Further guidance on how to prepare and conduct field inspections is
forthcoming in the Agency's upcoming Field Inspection Guide to be issued
in draft in September).  Pre-inspection planning and analysis should
culminate in a written inspection plan developed jointly by the technical
staff and the field inspector.
     After the site inspection, coordination continues when the inspec-
tor and the technical staff meet to discuss the findings of the field
                                    -3-

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inspection.  The outcome of this meeting should be a decision as to
whether compliance problems may exist and what additional information,
if any, is necessary to confirm the nature and extent of any potential
violations.  Often at this point, a follow-up inspection is appropriate
to verify whether or not compliance problems exist at the facility and to
gather any additional information necessary to support an enforcement
action.  Generally this more in-depth inspection will be performed by a
technical person, most likely an engineer or hydrogeologist, who has the
expertise to independently evaluate elements of the facility's ground-
water monitoring program.  Once back in the office, this person will be
able to consider guidance in the draft TEGD and his/her own professional
judgment to decide whether the owner/operator's monitoring program is
technically adequate.
     If the review indicates that the facility's monitoring program is
not in compliance with Part 265, the technical enforcement staff and the
permit writer should meet to conceptualize a technical remedy for
incorporation in an order.  Coordination between enforcement and
permitting is essential at this point to ensure that any enforcement
action taken is consistent with the long term monitoring obligations of
the facility.  As the COG points out, most facilities will have ground-
water obligations imposed by Part 2"70 and Part 264 over and above those
required by Part 265.  A technical remedy designed to address Part 265
violations should anticipate and be consistent with the facility's future
monitoring obligations pursuant to Part 264.  Likewise, if the facility's
operating or post-closure permit is due, the remedy in the order should
require the respondent to generate any ground-water data, information, or
plans required to meet the facility's permit application responsibilities
pursuant to Part 270.
     Once  the permit writer and enforcement official decide what activi-
ties should be compelled, the enforcement staff and regional counsel must
                                    -4-

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develop an enforcement strategy to secure the desired remedy.  Central to
the strategy is the selection of which order authority and (where appro-
priate) what regulatory citations should be used to compel the required
activities.  The COG provides useful background information on the various
order authorities and compares them with respect to the conditions for
order issuance, the types of actions they may compel, and applicable
appeal procedures, if any.  In addition, the COG provides guidance on how
to select among order authorities and how to relate specific technical
inadequacies back to the regulatory language.
     As a final step in the enforcement process, enforcement officials
and regional counsel must develop an order to compel the desired
activities.  Here both documents will come into play.  Enforcement
officials can consider technical information provided in the draft TEGD
to decide which methodologies, design configurations, and construction
materials should be mandated by the order.  Then enforcement staff and
counsel can use the COG for suggestions on how to write ground-water
orders that are easily enforced and effective at achieving the desired
remedy.  Together the TEGD and COG will help reduce the opportunity for
wasted effort, misunderstanding, and delay by ensuring that future
ground-water orders are explicit about which techniques and approaches
will be considered appropriate or adequate.
     Figure One illustrates the various steps in the enforcement process
and highlights the level of coordination necessary to fully implement the
guidance presented in this manual.  While the actors and steps needed to
remedy any particular ground-water problem will vary, the flow chart
illustrates the highly complex task of bringing a RCRA facility back into
compliance with the ground-water regulations.  The Agency hopes that this
manual will facilitate this task.
                                    -5-

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     ACTIVITIES
   PERSONS INVOLVED
PREINSPECTION ANALYSIS
AND PLANNING
i
i
  FIELD INSPECTION
  REVIEW OF FIELD
 INSPECTION REPORT

FOLLOW - UP
\
INSPECTION
i
TECHNICAL EVALUATION
OF FACILITY
INFORMATION - APPLICATION
OF TEGD
1
r
CONCEPTUALIZATION OF
TECHNICAL REMEDY
1
r
DEVELOPMENT OF
ENFORCEMENT CASE STRATEGY
                                 FIELD INSPECTOR
                                 TECHNICAL ENFORCEMENT
                                 STAFF
• FIELD INSPECTOR
• FIELD INSPECTOR
• TECHNICAL ENFORCEMENT
  STAFF
                              •  TECHNICAL ENFORCEMENT
                                 STAFF
                              •  TECHNICAL ENFORCEMENT
                                 STAFF
                              •  TECHNICAL ENFORCEMENT
                                 STAFF
                              •  PERMIT WRITER
                              •  TECHNICAL ENFORCEMENT
                                 STAFF
                              •  REGIONAL COUNSEL
   DEVELOPMENT OF
 COMPLIANCE ORDER
• TECHNICAL ENFORCEMENT
  STAFF
• REGIONAL COUNSEL
FIGURE 1.  OVERVIEW OF THE ENFORCEMENT PROCESS
                        -6-

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RCRA Ground-Water Monitoring
Compliance Order Guidance
                         Final
August 1985

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                               TABLE OF CONTENTS
                                                                            Page
1.   INTRODUCTION

     1.1  Purpose and Objectives                                            1-1

     1.2  Significance of the Interim Status  to Permitting  Transition        1-2

          1.2.1  Plume Characterization Under §270.14(c)(4)                  1-4

     1.3  Overview of the Enforcement Process                               1-6

          1.3.1  Case Initiation                                            1-8

          1.3.2  Facility Management Planning                               1-11

     1.4  Relationship to "Late and Incomplete Part  B  Policy"                1-13

     1.5  Structure of this Document                                        1-14

2.   REGULATORY OVERVIEW

     2.1  Interim Status Ground-Water Monitoring - Part  265                 2-1

          2.1.1  Detection Monitoring                                       2-2
          2.1.2  Assessment Monitoring                                      2-5

     2.2  Permit Regulations for Ground-Water Monitoring  -  Part  264

          2.2.1  Detection Monitoring                                       2-8
          2.2.2  Compliance Monitoring                                      2-9
          2.2.3  Corrective Action                                          2-12

     2.3  Permit Application Regulations - Part 270

          2.3.1  Information Requirements of  §270.14(c)                      2-14
          2.3.2  Information Requirements for Appropriate                   2-16
                 Part 264 Ground-Water System

3.   REGULATORY COMPARISONS

     3.1  Part 265 vs. Part 264 Detection Monitoring

          3.1.1  Well Placement                                             3-2
          3.1.2  Indicator Parameters                                       3-5
          3.1.3  Sampling Frequency                                         3-5
          3.1.4  Appropriate Sampling Techniques                            3-5
          3.1.5  Statistical Comparisons                                    3-7

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                           TABLE OF CONTENTS (con't.)
     3.2  Part 264 Detection Monitoring vs. Part 264 Compliance Monitoring

          3.2.1  Well Placement and Network Design                          3-8
          3.2.2  Establishing Background Concentrations                     3-10
          3.2.3  Sampling Frequency                                         3-11
          3.2.4  Statistical Comparisons                                    3-11

     3.3  Part 265 Assessment Monitoring vs.
          §270.14(c)(4)  Plume Characterization                              3-12
4.   OVERVIEW OF ORDER AUTHORITIES

     4.1  Comparison of §3008(a),  §3008(h),  and §3013 Orders

          4.1.1  Actions the Orders May Require                             4-2
          4.1.2  Conditions for Order Issuance                              4-5
          4.1.3  Formal Administrative Proceedings                           4-17

     4.2  Selection Among Order Authorities                                  4-18


5.  FASHIONING A REMEDY AND DEVELOPING THE ENFORCEMENT STRATEGY

     5.1  Types of Violators                                                5-1

     5.2  Profile of a "Transition-Period" Violator                          5-3

     5.3  Outline of the Remedy                                             5-4

     5.4  Discussion of the Remedy                                          5-9

          5.4.1  Design and Installation of  the Monitoring Network          5-9
          5.4.2  Confirmation of Leakage Based on Expanded Sampling          5-11
          5.4.3  Fulfillment of Applicable Part 270  Requirements             5-13

     5.5  Application of Enforcement Authorities to  the Remedy               5-15

          5.5.1  Selection of the Order Authority                           5-16
          5.5.2  Securing the Model Remedy Through a §3008(a) Order          5-18

     5.6  Variations on the Model Scenario                                   5-20


6.   DEVELOPING ORDERS

     6.1  Importance of Specificity                                         6-1

     6.2  Phased Orders for Ground-Water Monitoring  Violations               6-3


                                    ii

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                      TABLE OF CONTENTS (continued)

                                                                          page


 6.3  Technically Specific Orders                                         6-6

 6.4  §3008(a) Orders                                                     6-13

 6.5  §3013 Orders                                                        6-16

 6.6  §3008(h) Orders                                                     6-17


                           TABLE OF FIGURES


 1.1  Model of the Enforcement Process                                    1-7

 3.1  Relationship of the Waste Management Area to                        3-4
      the Point of Compliance

 3.2  Well Placement in Compliance Monitoring                             3-9

 4.1  Comparison of Order Authorities                                     4-3

 4.2  Ground-Water Performance Standards                                  4-8

 4.3  Relationship of Technical Inadequacies to Ground-Water
      Performance Standards                                               4-9

 5.1  Violator-Classification Scheme                                      5-2

 5.2  Ground-Water Monitoring Sequence as Originally Envisioned           5-6

 5.3  New Ground-Water Compliance Strategy Based on Condensed
      Monitoring Sequence                                                 5-10

 5.4  Model Remedy with Regulatory Citations                              5-18

 5.5  Variations on Model Remedy and Enforcement Response                 5-24

 6.1  Possible Elements of a Technically-Specific Order                   6-8



                           LIST OF APPENDICES


Appendix A:  Model Phased Order                                           A-l

Appendix B:  Diagram of Administrative Proceedings                        B-l
                                  iii

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                                CHAPTER 1

                              INTRODUCTION
1.1  Purpose and Objectives


     The purpose of this document is to guide enforcement officials in develop-

ing administrative orders to address RCRA ground-water monitoring violations at

interim status land disposal facilities.1  The document's primary objective is

to promote the development of orders that correct interim status violations

in a manner that is consistent with the needs of the RCRA permitting process.

Enforcement personnel are encouraged to involve permit writers in the formu-

lation of technical remedies to ensure that enforcement remedies are consistent

with the long-term monitoring responsibilities of the facility.


     The guidance is intended to apply to the RCRA-authorized States as well

as to EPA regional offices.  While State and Federal enforcement authorities

may differ (e.g., states may have different order authorities or different

maximum penalties), the States and EPA are enforcing essentially the same

set of regulations.  Therefore,  remedies designed by State enforcement

officials should be similar to those outlined in this document.


     The document will not be concerned with policy matters such as how to

decide which cases to pursue or how to decide between administrative and
     1  This document covers only the requirements for ground-water monitoring
that apply to hazardous waste management units that were in existence on November
19, 1980.  It does not address monitoring requirements that may be imposed  on
solid waste management units as a result of the "continuing releases" provision,
§3004(u) of RCRA, as amended by the Solid and Hazardous Waste Act Amendments
of 1984.
                                  1-1

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judicial response.  Instead, the document focuses on the formulation of

technical remedies and on the appropriate technical content  of orders.

Specifically, it concentrates on how to fashion ground-water remedies for

facilities operating during the transition period between interim status

and permitting.


1.2  Significance of the Interim Status to Permitting Transition Period


     The Agency and the regulated community are now entering a period unique

in the life of the RCRA program — the period after which all Part B permit

applications are due, but before all facilities have been permitted.  EPA

and the States have already received many Part B applications.  By November

8, 1985 the Part B permit applications of all the nation's land disposal

facilities will be due.2  it is likely, however, that it may take several

years for EPA to process and finalize permits for all these  facilities.   As

a result, many facilities will face a fairly long period of  time between the

due date of their application and the issuance or denial of  a permit.


     The existence of this transition period is significant  because it  is

the only time in the life of the RCRA program that land disposal facilities

will be bound by the interim status ground-water regulations (Part 265)  and

the permit application regulations (Part 270).  It is the first time, therefore,
     2  The Solid and Hazardous Waste Act Amendments of  1984 require all
land disposal facilities to submit a Part B permit application within twelve
months after the enactment of the Amendments or lose interim status.  See
§3005(e) of the Resource Conservation and Recovery Act (RCRA).
                                  1-2

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that enforcement officials can draw upon the authorities of both Part 265




and 270 when fashioning technical remedies at interim status facilities.






     As described in Chapter 3, the Part 270 regulations impose additional




monitoring and information generating requirements on the owner/operators




of interim status facilities.  The Agency designed the interim status




(Part 265), permit application (Part 270), and permitting regulations




(Part 264) to be followed in sequence.  A facility moves from one phase of




monitoring to the next (and from interim to permitted status) by building




upon the information generated during the previous stage.  The monitoring




and cleanup obligations of an owner/operator also expand as the facility




approaches permitting and/or the evidence of ground-water contamination




increases.






     Unfortunately, certain facilities have not adequately implemented even




the first phase of the monitoring sequence, the installation of a competent




detection monitoring network.  Consequently, these owner/operators cannot




provide the sampling data or plume characterization required for a Part B




permit application.






    Enforcement officials can help solve this problem by crafting technical




remedies that integrate the requirements of Parts 265 and 270.  Facilities




that have failed to progress through the monitoring sequence as planned,




should be required to condense the sequence so as to prepare the facility




for permitting as rapidly as possible.  Much of this document concentrates




on exploring how enforcement officials can use the requirements of Parts
                                  1-3

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265 and 270, and other available authorities to design remedies that will

ease the transition between interim and permitted status.


     1.2.1  Plume Characterization Under §270.14(c)(4)


     In terms of ground-water monitoring, the most significant requirement

of the Part 270 regulations is the provision outlined in §270.14(c)(4).

This provision requires applicants to describe any plume of contamination

that has entered ground water and define its extent, and provides EPA with

the authority to compel sampling for the broad list of constituents listed

in Appendix VIII of Part 261 (hereafter referred to as "Appendix VIII").


     This provision applies to all facilities that have detected plumes

under interim status monitoring and to facilities that have not detected

plumes if the facility's interim status system is not capable of detecting

a plume should it occur.•*  Facilities with inadequate 265 monitoring

systems should not be allowed to avoid Appendix VIII sampling and assessment

activities simply because they have avoided compliance with RCRA ground-water

monitoring requirements in the past.  Moreover, such facilities should not

be allowed to delay undertaking the more comprehensive assessment and

sampling activities mandated by §270.14(c)(4), by first going back and
     -*  This interpretation has been consistently advanced in all previous
guidance documents that address this issue. (See: the RCRA Permit Writer's
Guidance Manual For Ground-water Protection, October 1983, p. 204; and the
November 29, 1984 policy memorandum from Lee Thomas and Courtney Price,
entitled, "Part B Applications with Incomplete Ground-water Monitoring
Data.") Moreover, this expectation has been made known to facility owners
through the Permit Applicant's Guidance Manual, May 1984 (See pps. 9-42
and 9-43).
                                  1-4

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implementing the less demanding monitoring protocol established in Part




265.  Requiring these facilities to sample for Appendix VIII constituents




is consistent with the language of §270.14(c)(4) and the general purposes




of the Part 265 requirements.






     One of the purposes of the Part 265 regulations was to prepare facili-




ties for permitting.  EPA assumed that data from detection and assessment




monitoring under Part 265 would identify facilities that had contaminated




ground water.  These data would serve as the foundation for developing the




ground-water information required to be submitted in Part B of the permit




application [§270.I4(c)].  Where an owner/operator has not complied with




Part 265 monitoring requirements, however, EPA cannot determine whether




the facility has contaminated ground water and hence cannot easily determine




which ground-water monitoring program should be written into the facility's




permit.






     At this point in the program, allowing an applicant to comply with




the literal requirements of Part 265, however, would cause unacceptable




delays.  An applicant that needed to "start-over" by installing or relocat-




ing monitoring wells could require as much as two and one-half years to




complete the entire Part 265/Part 270 monitoring sequence (see timeline in




Figure 5.2).  Consequently, where EPA finds that an applicant has not




instituted an adequate monitoring program under Part 265, the Agency will




require owner/operators to condense the Part 265/Part 270 monitoring sequence




in order to generate the ground-water data necessary for permitting (closure




or post-closure) as quickly as possible.  This condensed monitoring program




is described in more detail in Chapter 5.
                                  1-5

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1.3  Overview of the Administrative Enforcement Process






     The unique character of the transition period from interim status to




permitting demands both increased coordination between permit writers and




enforcement staff and a new conceptual approach to the enforcement process.




The cornerstone of this new approach is the fashioning of technical ground-




water remedies that satisfy the Agency's long terra regulatory objectives.






     To implement this approach, the Agency recommends a three-step enforce-




ment process (see Figure 1.1).  STEP 1 is to outline the technical remedy




sought.  In most cases, this step will require considerable planning and




close coordination between the enforcement staff and the permitting staff.




Enforcement officials and permit writers must work together to construct




remedies that generate the information necessary for permitting while




correcting deficiencies in the facility's interim status monitoring system.






     STEP 2 is to develop an enforcement strategy to secure the desired




remedy.  Central to this effort is the selection of the order authority




best suited to compel the remedy.  If regulatory provisions have been




violated, the enforcement staff should determine whether the desired remedy




can be secured through a §3008(a) order citing these violations. (See Chapter




4 for a description of the order authorities and a discussion of their use.)




If there is a question whether the entire remedy can be compelled using a




§3008(a) order, enforcement staff should consider using a different




enforcement authority (e.g.,  §3008(h), §3013,  §7003 or CERCLA §106 orders),




or a combination of authorities if necessary.
                                  1-6
                                                                              i

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                                              1-7

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      STEP 3 of the administrative enforcement process is the development




of the order.  The order is the mechanism by which the Agency ensures that




the desired remedy is actually executed by the facility.  The goal of this




step is to formalize exactly what actions the respondent must take in




order to come into compliance.  The more explicitly the Agency can express




its expectations, the less opportunity there is for misunderstanding,




wasted effort, and delay.  As Chapter 6 explains, it is important to develop




this specificity as early in the enforcement process as possible, although




unless default is expected, it may not be necessary to express it in the




compliance order accompanying the complaint.  Chapter 6 provides guidance




on how to write orders that are easily enforced and effective at achieving




the remedy developed in STEP 1.






     1.3.1 Case Initiation






     Targeting cases for this enforcement process is the responsibility of




both the enforcement staff and the permits staff.






     In the enforcement program, cases generally evolve from the discovery of




an inadequate interim status monitoring program.  Inadequate systems may be




identified as a result of routine facility inspections, more detailed ground-




water inspections, or enforcement file reviews.  Once a problem-facility




is identified, enforcement staff should immediately contact the permits




staff to determine the facility's status vis a vis the permitting program.






     Early coordination with the permits staff is important for two  reasons.




First, the permits staff may have information on the site that could aid
                                   1-8

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in the development of an enforcement action against the facility.  Where




complete, for example, a Part B application can provide valuable informa-




tion regarding a facility's wastes, the hydrogeology of a site, etc.  Even




where deficient, a Part B application can prove useful to enforcement officials




by highlighting gaps in the facility owner's understanding of his/her site.







     Second, coordination is necessary to avoid duplication of effort and to




ensure that actions taken by the enforcement division are "consistent with"




and "supportive of" the permitting process.  Consistency is important so




that the Agency presents a unified front to the facility.  For example,




before issuing a complaint the enforcement staff should know whether there




is an outstanding Notice of Deficiency (NOD) compelling the same activities.




"Supportive of permitting" implies consideration of the permit writer's




informational needs when designing remedies.  The permit writer must become




involved in the enforcement process early on so that (s)he can ensure that




his/her own permit-writing needs and the facility's future Part 264 monitoring




needs are accurately represented and accounted for during the development




of the remedy.







     Cases may also enter the enforcement process via the permits staff.  In




fact, permit wnriters (by virtue of their Part B reviews) are often in the best




position to identify problem cases.  Permit writers are encouraged to refer




cases to enforcement and use enforcement staff to facilitate the permit




process.







     Enforcement involvement may be appropriate,  for example, when a facility




has submitted a highly deficient Part B and past dealings with the company have
                                  1-9

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demonstrated that the owner/operator is unlikely to correct deficiencies in




a prompt and forthright manner.  In such cases, the permit writer should




consider referring the case to enforcement immediately after issuing a




general NOD that requires the submittal of the missing information within




a very short period of time.  Historically recalcitrant applicants should




not be given long periods of time under the informal NOD process to generate




data/information that they should have developed by the due date of their




permit; rather they should be compelled to develop this information on an




enforceable compliance schedule pursuant to an order.  Likewise, if a permit




writer has failed to make progress using the NOD mechanism, (s)he should




work with the enforcement division to use formal mechanisms to compel




compliance rather than continue to issue NODs.







     Permit writers should also expand their initial "completeness" review




of incoming Part Bs to include an abbreviated technical assessment of the




ground-water monitoring portion of the application.   While the permitting




staff clearly does not have the resources to consider all Part B applications




in full as they arrive, there are benefits in focusing briefly on the parts




of each application that are particularly troublesome for the regulated




community, are environmentally sensitive, or will require a long time for




the facility to revise if the application is inadequate.  Some aspects of




an application are so central to the adequacy of the permit in general




that it may be wise to perform an abbreviated assessment up front, rather




than wait until the entire permit can be reviewed to discover and correct




major deficiencies (e.g., the facility must install an entirely new well




system before it can generate the data necessary for permitting).
                                  1-10

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      The consequences of not identifying such deficiencies up front could




be significant delays in the permitting process or a weakening of future




enforcement cases because so much time has elapsed between the submittal of




the application and the issuance of a complaint.  If permit writers did




conduct abbreviated reviews on the ground-water portion of incoming applica-




tions, they could refer cases with major deficiencies to the enforcement




staff.  Enforcement officials could then use the combined authorities of




Parts 265 and 270 (or other authorities as necessary) to advance the facility




to the point where the ground-water monitoring portion of the permit could




be easily written when the facility's full application comes up for review.







     1.3.2  Facility Management Planning







     The enforcement process as described above demands a high level of




coordination between the enforcement and permitting staffs.  For any parti-




cular facility, the Agency and States must decide whether ground-water




problems should be addressed through enforcement or through the permitting




process.  Facility Management Planning (FMP) is the mechanism that Regions




and States should use to orchestrate this division of labor.







     As described in the Revised FY85 and FY86 RCRA Implementation Plans




(RIP), the draft National Permit Strategy (April 8, 1985), and the draft FMP




guidance (July 12, 1985), Facility Management Planning is an Agency tool




for coordinating effort and resources between the Regions/States and




enforcement/permitting.  Regions must develop a Facility Management Plan




for all "environmentally significant" facilities according to a schedule




laid out in the RIP.  Each plan must identify: 1) what action(s) should
                                 1-11

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be taken at (or by) a facility;  2) what tool (e.g.,  order,  NOD,  post-closure




permit) should be used to compel the action; and 3)  who (State or Region,




enforcement or permitting) has lead responsibility for ensuring that the




action is completed.






     Decisions regarding the above points evolve from a "facility analysis"




conducted by representatives from Regional and State permitting and enforce-




ment offices.   During the facility analysis, the various representatives




review the information available on a facility (e.g., Part  B,  inspection




reports,  etc.) and begin formulating a strategy for  handling that facility




in the short and long term.  All strategies devised  for individual facilities




must be in accord with the RIP and other Agency policies.






     Where actual or potential ground-water contamination exists, the




strategy will generally include data or information  gathering to support




the long-term goal of either issuing the facility an operating permit or




closing the facility and implementing corrective action for releases




into ground water.






     It is during the facility management planning process  that enforcement




officials and permit writers can initiate the type of coordination necessary




to implement a range of options including this guidance. The review group,




for example, may decide that eventually a facility should be issued a




permit, but in the interim the Agency should use an  order to compel the




facility to investigate possible ground-water contamination and develop




the appropriate permit application data and plans.  At this point, the




lead enforcement official should solicit the assistance of  the permit
                                 1-12

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writer in formulating the technical remedy necessary to advance the facility




toward permitting.






1.4  Relationship to "Late and Incomplete Part B Policy"






     On September 9, 1983, Lee Thomas and Courtney Price issued a memorandum




entitled, "Guidance on Developing Compliance Orders Under Section 3008 of




the Resource Conservation and Recovery Act; Failure to Submit and Submittal




of Incomplete Part B Permit Applications."  This memo, commonly referred to




as the "Late and Incomplete Part B Policy,"  affirmed the Agency's authority




to take enforcement action for late and incomplete permit applications.  It




set out the procedures for addressing Part B violators and established a




flat penalty amount that should be assessed in each case.






     The Late and Incomplete Part B policy has been largely superseded by




more recent policies and is further modified by this document.   First, the




"Enforcement Response Policy" (December 21, 1984) established that Submittal




of a late, incomplete or inadequate Part B is a Class I violation (see page




18).   In addressing Class I violations the Enforcement Response Policy states




that EPA and the States may issue warning letters prior to §3008(a)  complaints




if they wish but are not required to do so.  Therefore, the directive in the




Late and Incomplete Part B Policy that warning letters should always precede




§3008(a) complaints is superseded.






     Second, the Late and Incomplete Part B Policy established  a flat




penalty amount of $5,000.00.   That  requirement has since been superseded by




the "RCRA Civil Penalty Policy"  (May 8, 1984), which establishes a matrix




that  should be used to determine administrative penalty amounts.  The matriK
                                 1-13

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is based on two factors, the degree of a handler's deviation from regulatory




requirements and the potential for harm presented by the violation.  Thus,




penalty amounts should be determined individually for each Part B violator;




the flat $5000.00 amount should not be applied automatically.







     Finally, the Late and Incomplete Part B Policy envisioned issuing complaints




that require, simply, the submittal of missing information.  The Agency has




since realized, however, that incomplete Part B's seldom represent mere over-




sights on the part of the applicant.  More often, Part B's are incomplete




or inadequate because the applicant failed to generate the required informa-




tion and/or failed to comply with interim status requirements.







    When issuing a complaint against a Part B violater,  the Region or State




should not merely require the respondent to "submit the  information required




in Section 'XYZ' of the regulations."  Rather enforcement officials should




determine the underlying reasons for the poor Part B and detail in the




proposed order what needs to be done to ensure a proper  submittal.  Often




the reasons behind an inadequate Part B are extremely complex, especially




when the deficiencies involve ground-water monitoring.  Enforcement officials




can help ensure the adequacy of the next submittal by outlining in the




order the nature and scope of the work to be performed.   Further, Regions




and States should generally assess penalties for all Part 270  violations




and any contributing Part 265 violations.







1.5  Structure of this Document







     This document is divided into six chapters.  Chapter 2 presents an in




depth discussion of the Part 265 and Part 264 ground-water monitoring regula-
                                 1-14

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tions.  Chapter 3 builds upon this framework and explores the interrelation-




ship between the two sets of regulations.  These two chapters are designed




to give enforcement officials the regulatory perspective they will need to




design ground-water remedies that are consistent with and supportive of the




permitting process.






     Chapter 4 provides an overview of the enforcement tools available to




secure desired remedies.  It compares and contrasts the various order author-




ities and discusses some of the factors enforcement officials should consider




when designing enforcement strategies.






     Chapter 5 discusses how to fashion a technical remedy.  The chapter




uses a case-study approach to illustrate how enforcement officials can




construct remedies that correct present violations while advancing a facility




toward permitting.  The chapter develops a model remedy for a typical "transi-




tion-period" facility and then describes how to use the combined authorities




of Parts 265 and 270 to secure that remedy.






    Finally, Chapter 6 discusses how to write an order to secure the




desired remedy.  The chapter emphasizes the importance of specificity in




order writing and explores various strategies that may be followed in




developing and issuing administrative orders.  Appendix A includes a model




order that illustrate some of the principles developed in this chapter.






     The Agency has also prepared a draft document entitled, RCRA Ground-




Water Monitoring Technical Enforcement Guidance (TEGD).  This document




addresses specific technical elements of ground-water monitoring system




design.  For example,  it discusses the types of well construction methods
                                 1-15

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that the Agency considers acceptable for  yielding  representative water




samples.  The draft final version  of the  TEGD  is dated  August,  1985 and




is available from the Office of  Waste Programs Enforcement  (OWPE).
                                 1-16

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                                              CHAPTER 2



                                         REGULATORY  OVERVIEW
                 This  chapter  provides  an  overview of  the Part 265 and Part 264 ground-water



            monitoring regulations.   Tt  attempts  to  abstract  from the regulatory language



            and describe  how the  programs  were  intended  to  function  in the  real world.



            Enforcement and permitting  officials  are strongly encouraged to read this



            chapter  even  if they  are  familiar with the regulations.




                The  chapter discusses only the  requirements that apply to hazardous waste



            management units.   In accordance with the  Solid and Hazardous Waste Amendments



            of  1984, permitted facilities  may soon be  required to monitor solid waste



            management units as well  as  hazardous waste  management units.  However, the



            specific requirements  applicable to these  units have not yet been established



            and will not  necessarily  be  identical to the current Subpart F program detailed



            below.




            2.1   Interim  Status Ground-Water Monitoring  - Part 265, Subpart F




                 The goal of the  Part 265  regulations  Is to ensure that owners and



;            operators  of  interim  status  landfills, land  treatment facilities, and surface

t

;            impoundments  evaluate  the impact of their  facility on the uppermost aquifer
i

            underlying their site.  To achieve  this  goal, the regulations establish a



            two-stage  ground-water program designed  to detect and characterize the



            migration  of  any wastes that escape from a facility.




                 The focus of  both stages  of the  program is on evaluating the nature and



            extent of  leakage,  not on the  removal or treatment of contamination should it




                                            2-1

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be detected.  Removal and treatment of contamination deemed unacceptable




must be dealt with through the exercise of the Agency's enforcement author-




ities under §3008(h) or §7003 of RGRA, §106 of CERCLA, or through the RCRA




permitting process (See Chapter 4 on Order Authorities and Section 2.2.3




of this chapter).







     2.1.1  Detection Monitoring







     Detection monitoring, the first stage of interim status monitoring,




is required at interim status land disposal facilities unless the owner/




operator can demonstrate that there is a low potential for migration of




hazardous waste from his/her facility to water supply wells or to surface




water.   The objective of detection monitoring is to determine whether a land




disposal facility has leaked hazardous waste into an underlying aquifer




in quantities sufficient to cause a significant change in ground-water




quality.







     To accomplish this objective, the regulations direct the owner/operator




to install a monitoring network which includes wells located downgradient




from the facility at the limit of the waste management area and wells




located upgradient that are capable of providing samples representative of




ground water unaffected by the facility.  Although the regulations recognize




that for a small site with the simplest hydrogeologic subsurface three




downgradient wells and one upgradient well might suffice, the number,




depth,  and location of wells must ultimately be selected so that the network




meets the regulatory performance standard of immediately detecting any
                                  2-2

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migration of statistically significant amounts of hazardous waste or hazard-




ous waste constituents into the uppermost aquifer [§265.91(a)].







     To determine whether leakage has occurred, the owner/operator must




compare monitoring data collected downgradient from his/her facility to




background water quality data established over an initial period of one




year.  The comparison is based on three sets of parameters designed to




characterize water unaffected by the facility and to predict possible




leakage of hazardous waste.







     The first set of twenty parameters, listed in Part 265 Appendix III,




defines the general suitability of the aquifer as a drinking water supply.




These parameters were selected because they are recognized by the Safe




Drinking Water Act as important to overall drinking water suitability.







   The second set of parameters (chloride, iron,  manganese,  phenols, sodium,




and sulfate) establish general ground-water quality and can be used to




characterize the suitability of ground water for a variety of non-drinking




uses.  Information on these parameters is largely collected in anticipation




of future confirmation of leakage.  Should detailed assessment of ground




water prove necessary, historical data on these major ion groups will




help owner/operators predict the mobility of hazardous waste under actual




site conditions.







     The final set of parameters includes four measures selected as gross




indicators of whether contamination of ground water has occurred.  These




four indicators - pH, specific conductance, total organic carbon (TOG), and
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total organic halogen (TOX) - were chosen because of their widespread use,




their well-established test procedures, and their general ability to reflect




changes in the organic and inorganic composition of ground water.  Faced




with designing a monitoring program that would be responsive to a large




undefined set of chemical compounds at unspecified concentrations,  the




Agency chose to rely on broad, surrogate measures that could predict whether




significant contamination had occurred.






     The regulations require the owner/operator to sample and analyze for all




three sets of parameters quarterly for one year.  Quarterly sampling is




required so that seasonal effects will be incorporated into the characteri-




zation of background water quality.  At the end of the first year,  the owner/




operator must establish background for each contamination indicator by




averaging the quarterly measurements obtained for that parameter from the




upgradient wells.   These upgradient mean values are important because they




establish the initial background concentrations to which all subsequent




upgradient and downgradient concentrations will be compared.






     After initial background is established, the owner/operator continues




sampling on a less frequent schedule.   The ground-water quality parameters




(chloride, phenol, etc.) must be analyzed at least annually and the contam-




ination indicators (TOX, pH, etc.), at least semi-annually.






     At this point, however, detection monitoring begins to focus more




specifically on the four contamination indicators.  Each time a facility




samples for a contamination indicator, the owner/operator must compare the




values obtained from his/her upgradient and downgradient wells with the






                                  2-4

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mean values obtained for that parameter during the first year of background




sampling.  (Note that both upgradient data and downgradient data are compared




to first year mean data derived from upgradient wells).  The regulations




specify that the facility owner should use a Student's t-test to the .01




level of significance when making comparisons [265.93(b)]»







     If a Student's t-test for an upgradient well shows a significant increase




in the concentration or value of an indicator parameter (or any change in pH),




it may mean that sources other than the facility are affecting ground water.




Alternately, a change in upgradient water quality could be due to mounding of




contaminated ground water beneath the facility or a change in hydraulic




gradient such that originally upgradient wells are now downgradient relative




to the facility.  (This condition would be reflected in changes in ground-




water elevation measurements over time.)  Whatever the cause,  a significant




change in upgradient water quality should be investigated and noted in the




company's annual report to the Agency [§265.94(a)(2)(ii)].







     A Student's t-test for a downgradient well that shows an increase in an




indicator parameter (or any change in pH), signals potential ground-water




contamination and is the first indication that a facility may be leaking.




If a statistically significant change is detected, the facility moves into




the second phase of interim status monitoring, ground-water assessment.







     2.1.2  Assessment Monitoring







      Once a significant change in water quality triggers a facility into




assessment,  the owner/operator must notify the Agency and submit a proposed
                                  2-5

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program for determining whether hazardous wastes or their constituents have




entered ground water and if so, their concentration, rate,  and extent of




migration [§265.93(d)(2)].   Because detection monitoring parameters are




non-specific, a statistically significant change in one parameter may not




necessarily represent migration of hazardous waste constituents into ground




water.  For example, pH could change independent of contamination if recharge




patterns at the site shifted such that ground water infiltrated through




formations with significant buffering capacity.   The first  step in assess-




ment monitoring, therefore, is to determine whether hazardous waste




constituents have indeed migrated into ground water.






     In many cases,  the detection monitoring network already installed at




the site can be used for this purpose.  Of course, use of the existing




system assumes that  the network is capable of detecting low part per billion




levels of hazardous  waste  constituents (listed Appendix VII of Part 261




and in §§261.24 and  261.33) in the uppermost aquifer.   If sampling reveals




no contamination, the owner/operator may return to his original detection




protocol or enter into a consent agreement with EPA to follow a revised




protocol designed to avoid  future false triggers.  If, on the other hand,




contamination is confirmed, the owner/operator must begin characterizing




the rate and extent  of migration.






     Normally, assessment  monitoring will require installation of addi-




tional well clusters located to define the vertical and horizontal extent




of the plume.  Unlike detection monitoring where wells would be placed




more or less evenly  along  the downgradient border of the waste management
                                  2-6

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area, wells in assessment monitoring could be concentrated in one area of




the site so as to track the migration of a localized discharge.  In addition




to direct sampling for hazardous waste constituents, the owner/operator




may rely on indirect techniques, such as electrical resistivity or ground-




penetrating radar, to help define the boundaries of a plume.







     Based on these techniques, the owner/operator must submit to EPA (as




soon as technically feasible), a written report assessing the quality of




ground water at the facility (§265.93(d)(5)).  After this initial assess-




ment of ground-water contamination, the facility must continue assessment




monitoring at least quarterly until the facility closes or is permitted.




Additionally, the owner/operator must continue detection monitoring in any




wells unaffected by the initial leak (i.e., wells away from the edge of




the plume where no hazardous waste constituents have been detected or




wells around other non-leaking units).







     It is important to note that no direct regulatory consequences flow




from a finding of contamination in assessment monitoring.  The purpose of




assessment monitoring is strictly to acquire information to support future




decisions regarding the need for corrective action.  The purpose does not




include determinations of whether or not such facilities are  environmentally




acceptable.  Strategies for cleaning up unacceptable contamination must  be




developed through the permitting process or through enforcement action




under §3008(h), §7003, or under CERCLA §106.
                                  2-7

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2.2  Permit Regulations for Ground-water Monitoring - Part  264,  Subpart F






     The primary goal of Part 264 ground-water monitoring is  to  ensure




that owners and operators of facilities handling hazardous  waste detect any




release of contamination into ground water and take corrective action when




such contamination threatens human health or the environment.  To achieve




this goal, the regulations establish a three-stage program  designed to




detect, evaluate, and correct ground-water contamination arising from leaks




or discharges from hazardous waste management facilities.  The program is




graduated so that the monitoring and clean-up responsibilities of the




owner/operator expand as the impact of the facility on ground water becomes




better understood.






     2.2.1  Detection Monitoring






     The first stage of the program, detection monitoring,  is implemented at




facilities where no hazardous constituents are known to have  migrated from




the facility to ground water.  Applicants who are seeking permits for new




facilities or for interim status facilities that have not triggered into




assessment, would generally qualify for Part 264 detection monitoring (the




latter assumes, of course, that the interim status monitoring network is




adequate to detect contamination).






    The actual monitoring requirements of Part 264 detection are similar to




those already imposed under the interim status regulations.  In  the preamble




to the regulations EPA expressed the expectation that properly designed




interim status networks would be sufficient for most permit detection
                                  2-1

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systems.  In Part 264 detection monitoring, however, the permittee routinely

monitors for a select set of indicator parameters specified in the permit

rather than for the four indicator parameters specified in the Part 265 reg-

ulations.  Should the arrival of leachate from the facility be indicated

by an increase (or pH decrease) of any of the parameters relative to background,

the permittee must immediately sample for all constituents listed in Appendix

VIII in order to determine the chemical composition of the leachate.^  In

addition, the owner/operator must submit, within 180 days, an engineering

feasibility plan that outlines an approach for cleaning up ground water should

clean up prove necessary [§264.98(h)(5)].  The facility in turn is obliged

to move into the next phase of the Part 264 ground-water program - compliance

monitoring.


     2.2.2  Compliance Monitoring


     The goal of compliance monitoring is to ensure that leakage of hazardous

constituents (Part 261 Appendix VIII constituents) into ground water does not

exceed acceptable levels.  Through the permit, therefore,  the Agency and

the facility must specify what level of each constituent will be considered

environmentally acceptable and then establish a program of routine monitoring

to ensure that acceptable levels are not exceeded.  If concentration limits
     ^ The Agency may use enforcement discretion so as not to require sampling
for those substances that are unstable in ground water or for which there
exists no EPA-approved test method.  For a list of these substances see the
August 16, 1984 memo from Courtney Price and Lee Thomas entitled,  "Enforcing
Ground-Water Monitoring Requirements in RCRA Part B Permit Applications."
The Agency has also proposed to waive monitoring requirements for such sub-
stances (See 49 FR 38786, October 1, 1984).
                                 2-9

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are exceeded, the permittee must institute a corrective action program




designed to bring the concentration levels back within acceptable limits.






     The permit writer establishes the framework for a compliance monitoring




program by incorporating a ground-water protection standard into the permit.




The standard consists of four elements, each of which must be specified in




the permit.






     The first element of the standard is a listing of all Appendix VIII




hazardous constituents present in ground water that could reasonably have




been derived from the facility.  The burden of demonstrating that a particular




Appendix VIII constituent could not reasonably be derived from a facility,




lies with the owner/operator.  Claims of exclusion must be based on a




detailed chemical analysis of the facility's waste and must consider possible




chemical reactions that could occur in the facility or during the migration




of leachate into ground water.  An exclusion is also available for an




individual constituent if the owner/operator can demonstrate that it is




incapable of posing a substantial present or potential hazard to human health




or the environment.  Given this standard of proof, however, exclusions will




be granted rarely; the ground-water protection standard of most facilities,




therefore, will include all Appendix VIII constituents detected in ground




water.






     The basis for identifying the Appendix VIII constituents present in




ground water will vary depending on the status of the facility at the time of




establishing the protection standard.  Facilities that are operating under




detection monitoring permits will have identified the Appendix VIII consti-
                                 2-10

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tuents present in ground water as part of their detection monitoring respon-

sibilities [see §264.98(h)(2)].  Facilities that have not yet received

permits and are operating under Part 265 assessment monitoring, however,

may have to perform additional sampling because assessment monitoring

requires the determination of Appendix VII substances rather than the full

complement of constituents listed in Appendix VIII.  (Appendix VII is but a

subset of Appendix VIII - see section 3.3 for further explanation of this

point).  Consequently, the facility owner in Part 265 assessment monitoring

will have to undertake additional sampling and analysis before the facility

can be permitted.  [Note: the permit application regulations (Part 270)

require facilities to characterize plumes with respect to Appendix VIII

constituents (see §270.14(c)(4))].


     The second element of the ground-water protection standard is the

specification of a concentration limit for each hazardous constituent

listed in the facility permit.  Where possible, concentration limits must

be based on well established numerical concentration limits for specific

constituents.  Where established standards are not available, the permit

writer must set concentration limits so as to prevent degradation of water

quality unless the owner/operator can demonstrate that a higher limit will

not adversely affect public health or the environment.  Following this

approach, concentration limits must be set at either:
        1)  the maximum concentration limit for drinking water established
            by the National Interim Primary Drinking Water Regulations
            (where applicable);

        2)  the background level of the constituent in ground water; or
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        3)  an alternate concentration limit (ACL) if the owner/operator
            can demonstrate that a higher concentration will not pose a
            substantial present or potential hazard to human health or the
            environment (§264.94).
     The third and fourth elements of the ground-water protection standard

are the point of compliance and the compliance period.  The compliance

point is the location at which the ground-water protection standard applies

and hence is the point where monitoring must occur.   The regulations

specify that the point of compliance is the vertical surface located at

the downgradient limit of the waste management area  (§264.95).   The com-

pliance period is the period during which the ground-water protection

standard applies.  This period is equal to the active life of the facility

plus the closure period [§264.96].


     After the ground-water protection standard is established,  the

permittee must monitor ground water to ensure that the facility  continues

to comply with its protection standard.  If properly designed and constructed,

the monitoring network established for detection monitoring should be

adequate for this purpose.   In addition,  the permittee must sample annually

for Appendix VIII constituents to detect  any additional substances that

may have entered ground water.  Should sampling reveal a new constituent,

the permit writer must amend the protection standard to include  a concentra-

tion limit for the new constituent.


     2.2.3  Corrective Action


     If compliance monitoring reveals that a facility is exceeding its

ground-water protection standard (i.e., the concentration of a hazardous
                                 2-12

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constituent in ground water exceeds the maximum limit established in the




permit), the facility must institute a corrective action program.  The




goal of corrective action is to bring the facility back into compliance




with its protection standard.  To achieve this goal, the facility must




develop a plan for removing the hazardous constituents or for treating the




constituents in place [§264.99(i)(2)].  If approved by the Agency, the




permit writer will incorporate this plan into the facility permit.







     The permit writer must also include in the permit a program of ground-




water monitoring adequate to demonstrate the effectiveness of the corrective




action measures [§264.100(d)].  At the limit of the waste management area,




this program will be essentially the same as the compliance monitoring




program although permit writers may want to increase the number of wells




and the frequency of monitoring at or near the compliance point where the




plume appears to be concentrated.  Also, owner/operators will be required




to install additional monitoring wells near the downgradient edge of the




plume so that the Agency can monitor the effectiveness of the corrective




action program.







     The permittee must implement corrective action measures until compliance




with the ground-water protection standard is achieved.  Once contamination




has been reduced below the concentration limit set in the permit,  the facility




may discontinue corrective action measures and corrective action monitoring,




and return to the monitoring schedule established for compliance monitoring.




If compliance is not achieved before the end of the compliance  period
                                 2-13

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specified in the permit, the permittee must continue corrective action




until monitoring shows that the ground-water protection standard has not




been exceeded for three years [§264.100(f)].






2.3  Permit Application Regulations - Part 270






     Part 270 of the regulations specifies the information an applicant




must submit to the Agency when applying for a permit.   The information




requirements related to ground-water monitoring can be organized into two




basic groups.  The first group, outlined in §270.14(c), establishes the




nature of the facility's impact on ground water,  as well as the hydro-




geologic characteristics of the site's subsurface and  the extent of the




waste management area.  The second group includes the  information necessary




to establish one of the three Part 264 ground-water monitoring and response




programs (detection monitoring, compliance monitoring,  and/or corrective




action).






     2.3.1  Information Requirements of §270.14(c)






     Section 270.l4(c) includes four basic information requirements.




First,  applicants must present the data collected during interim status




monitoring (where applicable).  If the facility has implemented a satis-




factory monitoring system under interim status, these  data should provide




information useful for determining whether hazardous constituents have




entered ground water.  The Permit Applicant's Guidance Manual for Hazardous




Waste Land Treatment, Storage, and Disposal Facilities (May, 1984) states




that this provision requires submittal of background information to support
                                 2-14

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these data as well as the data themselves.  For example, the Applicant's

manual Instructs owner/operators to submit:


          o  a map showing the location of upgradient and downgradient
             wells;

          o  a copy of the facility's sample and analysis plan;

          o  a description of the statistical procedure used in proces-
             sing the data submitted;

          o  copies of water analysis results; and

          o  a description of the design and construction of each well.


     Second, the applicant must identify the uppermost aquifer and hydraul-

ically interconnected aquifers beneath the facility property.  The application

must indicate ground-water flow directions and provide the basis for the

aquifer identification (i.e. , a report written by a qualified hydrogeologist

on the hydrogeologic characteristics of the facility property supported by

at least the well drilling logs and available professional literature).

This information is needed to evaluate the adequacy of the ground-water

monitoring system that the applicant proposes to operate after the permit

is issued.  (Readers are referred to the Permit Applicant's Manual for a

discussion of what constitutes an adequate hydrogeologic investigation;

additional guidance will be provided by the final TEGD).


     Third, §270.]4(c)(3) requires the applicant to delineate the waste

management area, the property boundary, and the proposed point of compliance.

This information should be transposed onto a topographic map along with, to

the extent possible, the designation of the uppermost and any interrelated

aquifers.
                                 2-15

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     Finally, §270.14(c)(4) requires applicants to describe any plume of

contamination that has entered ground water by:


             o  delineating the extent of the plume;  and

             o  identifying the concentration of each Appendix VIII
                constituent throughout the plume or identifying the
                maximum concentrations of each Appendix VIII con-
                stituent in the plume.


This requirement applies to the following three categories of facilities:


     1.  Facilities where no interim status monitoring data are available
         (e.g.,  waste piles, facilities that wrongly  claimed a waiver
          from interim status ground-water monitoring requirements);

     2.  Facilities whose interim status data indicate contamination; and

     3.  Facilities whose Part 265 detection monitoring system is inadequate
         to determine whether or not a plume of contamination exists.


     As the Permit Applicant's Guide indicates (page  9-42),  the permit writer

will evaluate the ability of the facility's well network and sample and

analysis plan to determine the presence of a plume.   If EPA determines that

the interim status monitoring program was inadequate  to detect contamination,

the applicant will be instructed to provide the information required by

§270.14(c)(4).


     2.3.2  Information Requirements for Appropriate  Part 264 Ground-water System


     Part 270 also requires permit applicants to submit information sufficient

to establish the appropriate ground-water monitoring  program under Part 264.

The information requirements relevant to any particular facility depend on the
                                 2-16

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status of that facility at the time of permitting.  If monitoring conducted




pursuant to Part 265 and Section 270.14(c)(4) has not revealed contamination,




the applicant must submit the information, data, and analysis necessary to




implement a detection monitoring program.  If monitoring has revealed the




presence of hazardous constituents in ground water at the point of compliance,




the applicant must outline a program of compliance monitoring and submit




a study that estimates the engineering feasibility of various forms of




corrective action [§270.14(c)(7)].  Where the concentration of a hazardous




constituent exceeds background or an alternate concentration level proposed




by the applicant, (s)he must instead submit a detailed plan for corrective




action and a description of the monitoring program intended to demonstrate




the adequacy of the corrective measures [§270.14(c)(8)].  Detail concerning




the specific information required to support each type of monitoring program




is provided in the regulations and expanded upon in the Permit Applicant's




Guidance Manual  §§ 9.6 - 9.8.
                                 2-17

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                                CHAPTER 3




                         REGULATORY COMPARISONS
      In order to devise enforcement strategies that are consistent with




and supportive of the permitting process, it is important to have an under-




standing of how the Parts 265 and 264 ground-water monitoring regulations




interrelate.  As mentioned previously, the Agency envisioned the interim




status period as a time in which to develop, among other things, the infor-




mation necessary to support permitting.  Indeed, one of the overall goals




of interim status monitoring was to generate the data necessary to decide




whether the facility permit should include a detection monitoring program,




a compliance monitoring program, or a program for corrective action.






    In short, the Agency envisioned a smooth transition from interim status




detection monitoring, through assessment, to final permitting.  A facility




would proceed from one phase of monitoring to the next by building upon the




monitoring system implemented during the previous stage.  While interim




status monitoring focused on a smaller number of constituents in order to




limit the routine monitoring obligations of the owner/operator, the Agency




never considered the physical well networks of the Part 265 and Part 264




programs fundamentally different.  Sampling protocols and schedules would




change to be consistent with the new objectives of each monitoring phase,




but the physical well network (if properly designed) could serve throughout




the life of a facility.  A Part 265 detection system, for example, may




need to be expanded to meet the needs of compliance monitoring, but with




proper foresight, the existing wells need not be replaced.






                                  3-1

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     Unfortunately, certain interim status monitoring systems are insufficient




in quality and breadth to meet the Part 265 standards.  Of those that meet




the minimum standards, few have been designed in expectation of the facility's




future monitoring obligations.  As a result, facilities that should be




close to meeting their Part 264 ground-water obligations,  are in fact not




prepared for the permitting process.






     If enforcement officials are going to help bridge this gap, they must




have a thorough understanding of exactly how the Part 265  and Part 264




regulations interrelate.   To aid officials in this effort,  this chapter




will outline the major similarities and differences between the requirements




of three ground-water monitoring programs: Part 265 detection vs.  Part 264




detection;  Parts 264/265  detection vs.  compliance monitoring; and Part 265




assessment monitoring vs. plume characterization activities conducted pursuant




to §270.14(c)(4).






3.1   Part 265 vs. Part 264 Detection Monitoring






     3.1.1  Well Placement






    For all practical purposes, the requirements governing well placement




are the same for both Part 265 and Part 264 detection monitoring.   Whereas the




regulatory language differs slightly, a network designed to meet the Part 265




standard should be substantially the same (in terms of well locations and




depths) as one designed to meet the Part 264 standard.






     Both programs include a performance standard for background well place-




ment that requires a sufficient number  of wells, installed at appropriate
                                  3-2

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locations and depths, to yield ground-water samples that are: 1) representative

of the background water quality in the uppermost aquifer; and 2) unaffected

by leakage from the facility [Compare §265.91(a)(l) with §264.97(a)(l) and

§264.97(a)(2)].


    Both programs also include similar language regarding the placement of

downgradient wells, although the Part 265 regulations require placement at

the "limit of the waste management area," whereas the Part 264 regulations

require placement at the "point of compliance"  [cf., 265.91(a)(2) and

264.97(a)(2)].  While worded differently, the physical well location dictated

by both programs is, by definition, essentially the same.  The regulations

define the "waste management area" as "the limit projected in the horizontal

plane of the area on which waste will be placed during the active life of a

regulated unit" [§264.95(b)],5   Where there is more than one unit at a facility,

the waste management area is described by an imaginary line circumscribing

the various units.  Hence, wells in Part 265 detection monitoring must be

placed at the edge of the waste management area.
5  The Permit Applicant's Manual further qualifies this definition by
noting that for Part 265 systems, EPA will evaluate the areal extent of the
waste management area at an expanding facility against the regulatory man-
date to choose well locations so as "to immediately detect" the migration
of hazardous waste into the uppermost aquifer.  For permit applications,
EPA will evaluate the proposed waste management area against the policy of
designing monitoring programs so as to give an early warning of the release
of contaminants.  In either case, EPA does not recommend that facility
owners propose a waste management area whose limit is geographically remote
from the active waste handling zone.  Rather, monitoring wells should be
closely associated with the active zone even if this means redefining the
waste management area as a facility expands.
                                  3-3

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       Wells in Part 264 detection must  also  be  placed at the edge of the

waste management area because the point  of  compliance  is, by definition,

the edge of the waste management area  projected  downward into the uppermost

aquLfer  [see §264.95(a)].  The point of  compliance  is, therefore, the limit

of the waste management area described in  three  dimensional space (See

Figure 3.1).  Both regulations mandate,  consequently,  that wells are located

along the same thin land surface.  Parts 265  and 264 similarly require

well spacings and depths capable of detecting statistically significant

contamination in the uppermost aquifer.
Figure 3.1
RELATIONSHIP OF THE WASTE MANAGEMENT AREA
        TO THE POINT OF COMPLIANCE
LIMIT OF THE
WASTE MANAGEMENT
AREA
                              4-  SURFACE IMPOUNDMENT
                              4-
                                  THREE DIMENSIONAL
                                  POINT OF COMPLIANCE
                                  UPPER MOST AQUIFIER
                                    GROUND-WATER
                                        FLOW
                                   3-4

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     3.1.2  Indicator Parameters






     The concept of sampling for parameters designed "to indicate contami-




nation" is the same for both Parts 265 and 264 detection monitoring.  The




Part 265 regulations mandate the use of four specific indicators for all




facilities, whereas the Part 264 regulations require the permit writer to




specify a set of site-specific indicator parameters in each facility permit.




The greater latitude and scope afforded by the Part 264 regulations




allows the permit writer to design the detection program around the partic-




ulars of a specific facility.  Rather than rely on broad, generic measures




such as TOG, the permit writer can compel sampling for specific constituents




known to be in the facility's waste.  As a result, a Part 264 detection




system can be designed to be more sensitive than the Part 265 system speci-




fied in the interim status regulations.






     3.1.3  Sampling Frequency






     Both the Part 265 and Part 264 regulations require quarterly sampling




for one year to establish background, and at least semi-annual sampling




thereafter.









     3.1.4  Appropriate Sampling Techniques






     The choice of the sampling device and the appropriateness of the materials




used in the device are dictated by the needs of the most sensitive constituent




of interest.  In general, the most sensitive constituents will be volatile
                                  3-5

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organics because as a class, volatile organics are highly susceptible to




degassing and chemical interference with sampling-device materials (e.g.,




silicon tubing).  For most monitoring applications,  therefore,  the sampling




device will be chosen to meet the needs of volatile  organics.






     Given that the Part 265 detection program necessarily includes a volatile




organic parameter, TOX, that can be measured reliably at the 5  ppb level (see




Method 9020 in "Test Methods for Evaluating Solid Waste, SW-846),  sample




device selection for interim status monitoring will  always be  dictated by




the needs of volatile organics.   Therefore,  if a Part 264 detection program




includes sampling for any volatile organic,  then the sampling  devices and




materials appropriate for each program would be the  same.  Considering that




264 detection systems almost always contain at least one volatile  organic




indicator, the sampling requirements of both 265 and 264 detection monitor-




ing will be essentially equivalent in most cases.






     It is conceivable, however, that a sampling device appropriate for Part




264 sampling would NOT be appropriate for Part 265 detection if the permit




writer did not require sampling for any volatile organics (e.g., if the




facility were a monofill of hexavalent chromium and  the permit  writer elected




chromium as the only Part 264 detection parameter).   Such a facility could




use a sampling device normally inappropriate for measuring volatile organics.




If, however, a chromium waste facility ever detected contamination, the




regulations require the owner/operator to sample immediately for the conti-




ituents listed in Appendix VIII (including many volatile organics).  The
                                  3-6

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facility owner, therefore, would have to change sampling devices to ensure




 that he acquired representative samples.






      Recognizing this fact, it may be in the best interest of the owner/




operator to consider his/her long-term monitoring needs when purchasing sampling




equipment.  To the extent that facility owners purchase and use equipment for




detection monitoring that will still be suitable should leakage occur, the




sampling mechanisms appropriate for 265 and 264 detection monitoring once




again converge.






     3.1.5  Statistical Comparisons






     Both the Parts 265 and 264 detection monitoring regulations require the




owner/operator to determine whether there has been a statistically significant




increase over background for any indicator parameter specified in the




program (or decrease for pH).






     The statistics used to make this determination,  however,  vary between the




programs in two important ways.  First, the Part 264 detection program requires




the owner/operator to use a specific Student's t-test when defining significance




(the Cochran's Approximation to the Behrens Fisher Students t-test),  unless  he




can defend another statistical technique as substantially equivalent.   The Part




265 program, on the other hand, makes no allowance for an alternate statistical




technique, but the regulations do not specify a particular variant of  the Student's




t-test;  any Student's t-test is acceptable.






     Second, the Part 264 detection regulations require the test to be applied




to the .05 level of significance,  while the 265 regulations specify a  signifi-
                                  3-7

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cance level of .01.  The level of significance sets the balance between

the chances of the test falsely detecting contamination ("false positive")

and the test failing to identify contamination that has occurred.6  By

raising the level of significance for the Part 264 standards, the Agency

achieved greater assurance that the test would not fail to detect actual

contamination.  During the interim status period, the Agency was willing to

reduce the chances of "false positives" by accepting a slightly higher prob-

ability of failing to detect leakage.  This balance was acceptable for interim

status because the Agency knew it would have another opportunity to investigate

possible leakage during the permit application process.  For the permit

regulations, however, the Agency decided that a lower level of significance

would unduly compromise the ability of the test to detect contamination.


3.2  Part 264 Detection Monitoring vs. Part 264 Compliance Monitoring


     3.2.1   Well Placement and Network Design


     Well placements for compliance monitoring more closely resemble

detection monitoring networks than they do assessment networks.  One should

not assume that network configurations for compliance monitoring will resemble

configurations suitable for Part 265 assessment monitoring simply because both

programs represent a second phase of monitoring after detection monitoring.

In fact, in some cases the network installed for detection monitoring will
     6  Readers should note that this discussion pertains to the false positive
rate caused by the statistical test alone.  Many other factors, such as insuffi-
cient number of background wells, can cause a facility to trigger under detection
monitoring when contamination has not actually occurred.  In fact, many "false
positives" are not a function of statistics, but are a function of such things as
well location, sampling, and chemical analysis.


                                 3-8

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become the compliance monitoring  network;  all that will change is the sampling

protocol and the objective  of  the monitoring program.


     Given that compliance  monitoring is meant to evaluate contamination rather

than just detect it, there  is  a strong possibility that existing detection net-

works may have to be expanded  to  meet the broader objectives of compliance

monitoring.  The more complicated statistical techniques used to evaluate

monitoring data during  compliance monitoring, for example, may require a

greater number of background wells than the statistical approach used during

detection monitoring.   Likewise,  the permit writer may want to require

additional downgradient wells  in  the immediate vicinity of those wells where

contamination has been  detected.


     Additional wells are generally most appropriate when contamination has

been detected in only one or two  monitoring wells, indicating a localized

leak.  With localized leaks, only a limited amount of dispersion can occur

before the plume passes the point of compliance (see Figure 3.2).  As a

result, more wells may  be necessary to ensure that measurements of contami-

Figure 3.2
           GROUND-WATER
               FLOW
    LEGEND:

      0 EXISTING MONITORING WELL

      Q PROPOSED MONTORING WELL

         CONTAMINANT PLUME
                              LINED SURFACE
                               IMPOUNDMENT
BREAK IN THE
   LINER
                      FUTURE LOCATION OF
                     COMPLIANCE MONITORING
                            WELL
TRIGGERING WELL
                                   3-9

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nation represent the high concentrations characteristic of the plume's center,




rather than the lower concentrations normally found in the plume's periphery.






    In short, in some circumstances an existing detection system may have to




be expanded under compliance monitoring, but the general well configurations




for detection monitoring and compliance monitoring are the same.






     3.2.2  Establishing Background Concentrations






     The regulations specify that background concentrations for Part 265 and




Part 264 detection indicator parameters must be based on quarterly samples for




one year.  Under compliance monitoring, however, the regulations grant the




permit writer leeway on how to establish background.  (Recall that background




values are very important in compliance monitoring because in many instances,




these background values will be incorporated into the ground-water protection




standard as "concentration limits.")






     The permit writer has two options for establishing background




values for compliance monitoring constituents.  The permit writer may




establish concentration limits based on the mean of pooled background data




available at the time of permitting.  To ensure that sufficient data are




available for this purpose, the permit writer may require the applicant to




undertake an accelerated program of background sampling prior to permitting.






     Alternately, if there is a high temporal correlation between up- and




downgradient concentrations, the permit writer may specify that background




values be established by sampling upgradient wells each time ground water is




sampled at the point of compliance.  With this approach, background concentra-
                                 3-10

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tions are not established by averaging values obtained over time; rather,




background values are established anew after each sampling event.






     3.2.3  Sampling Frequency






     Since hazardous constituents are already present in ground water when




compliance monitoring begins, the regulations require a more aggressive sampling




schedule for compliance monitoring than for detection monitoring.  Under




detection monitoring, the regulations state that sampling for indicator




parameters should occur at least twice a year (once background is established)




[§265.92(d)(2>].  By contrast, the compliance monitoring regulations require




routine sampling of the hazardous constituents listed in the facility's




protection standard at least quarterly.









     3.2.4  Statistical Comparisons






     Whereas the regulations specify the use of a specific t-test protocol




when evaluating monitoring data obtained during detection monitoring, they




do not detail specific procedures for use during compliance monitoring.  The




compliance monitoring regulations require that the statistical procedures




used be appropriate for the distribution of data encountered and provide a




reasonable balance between the probability of falsely identifying and failing




to identify violations of the ground-water protection standard.






     Moreover, unlike detection monitoring, the compliance monitoring




regulations do not establish a particular level of significance for use




when making comparisons.  The high number of comparisons likely in most




compliance monitoring programs will increase the probability of false
                                 3-11

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positives; therefore, permit writers are granted the latitude to choose a




level of significance that will strike an appropriate balance between the




probability of false positives and false negatives.







3.3  Part 265 Assessment Monitoring vs. §270.14(c)(4) Plume Characterization







     Both Part 265 assessment monitoring and §270.14(c)(4) require facility




owners to assess any plume of contamination that has entered ground water.




The programs differ, however, in two important ways.







     First, the Part 265 assessment program applies only to facilities that




have detected the existence of a plume through Part 265 ground-water monitoring,




The §270.14(c)(4) requirements, on the other hand, apply to any facility




that has not demonstrated the absence of contamination through proper Part




265 monitoring.







     Second, Part 265 assessment requires monitoring for hazardous wastes or




"hazardous waste constituents" [see §265.93(d)(4)], whereas §270.14(c)(4)




requires sampling for "hazardous constituents."   "Hazardous constituents"




are those substances listed in Appendix VIII of Part 261.  "Hazardous waste




constituents," as defined in §260.10, are the constituents that provided the




basis for listing each of the hazardous wastes identified in Part 261 Sub-




part D, or a constituent listed in Table 1 of §261.24 (constituents with




National Interim Drinking Water Standards under the Safe Drinking Water




Act).







     Appendix VII identifies the specific constituent(s) responsible for




the listing of wastes from the non-specific sources in §261.31 as well as







                                 3-12

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from the specific sources contained in §261.32.  In the case of any of the




discarded commercial chemical products, off-specification products, and




spill residues listed in §261.33, the chemical product itself is considered




the constituent responsible for the listing of the substance in Part 261.






     Interim status assessment monitoring, therefore, requires the owner/




operator to sample for any Appendix VII constituent, any substance listed in




§261.33, or any substance listed in §261.24 that is in the facility's waste.




Section 270.14(c)(4), on the other hand, requires sampling for the full comple-




ment of Appendix VIII constituents.






     This difference between the two programs is significant.  Part 265 "s




reliance on "hazardous waste constituents" rather than on Appendix VIII




constituents could mean that certain constituents in a facility's waste




would not be included in a Part 265 assessment monitoring program.






     A number of factors may be responsible for the exclusion of certain




constituents.  First, the constituents identified in Appendix VII as the




basis for listing individual wastes in Part 261, are not necessarily a complete




list of all hazardous constituents contained in each waste.  In developing




Appendix VII, EPA did not attempt to conduct an exhaustive analysis of all




constituents in the waste that could have provided a basis for the listing




(§261.11 provides the criteria the Administrator must use when listing a




waste).  Rather, the Agency identified a few of the more commonly known consti-




tuents in each waste that could pose a substantial present or potential hazard




to human health or the environment.
                                 3-13

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       Second,  Appendix VII  only  applies  to  listed  wastes;  it  does  not address

  hazardous  constituents that  may be  present in wastes  deemed  hazardous because

  they exhibit  one  of  the characteristics in Part  261.   Table  1  of  §261.24

  addresses  wastes  exhibiting  the characteristic of E.P.  toxicity,  but "hazardous

  waste constituents"  do not include  non-listed wastes  deemed  hazardous because

  of corrosivity,  reactivity,  or  ignitability.   Moreover,  Appendix  VII and

  Table 1  of §261.24 were not  developed to address  the  constituents that may be

  formed when various  wastes are  mixed in a  regulated unit, or when wastes react

  with constituents in the soil.   As  a result,  a Part 265 assessment program

  could conceivably fail to  include a consitituent  of concern  at a  particular

  facility.   It must be recalled, however, that the interim status  regulations

  were designed to  be  self-implementing,  not exhaustive.  '
     1  Chapter 4 explores the various enforcement authorities available to
compel sampling for Appendix VIII constituents at interim status land disposal
facilities if such sampling appears necessary.  Depending on the circumstances,
a §3008(a) order enforcing §270.14 (c)(4), a §3013 order or a §3008(h) may be used
(See section 4.1.1 for further explanation).
                                   3-14

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                                  CHAPTER 4

                        OVERVIEW OF ORDER AUTHORITIES
     There are a variety of order authorities available to correct ground-

water problems at RCRA hazardous waste facilities.  Section 3008(a) of RCRA

provides for the issuance of orders and for the commencement of civil suits

when any requirement of Subtitle C is violated.  RCRA also establishes

enforcement authorities under Sections 3004(v), 3008(h), 3013, and 7003.

Any of these authorities may be used, in certain circumstances, to address

ground-water problems.  In addition, the enforcement authority in §106 of

CERCLA may be available in many cases.8


     While there will undoubtedly be instances where it is most appropriate

to file a civil suit under §3008(a), §3008(h), or §7003, or to initiate

criminal proceedings under §§3008(d) and (e), there are three order author-

ities that should prove most useful in addressing inadequate ground-water

monitoring programs:


      o §3008(a) orders seeking penalties and/or injunctive relief
        for violations of Part 265 Subpart F and Part 270;

      o §3008(h) orders seeking the investigation and implementation of
        corrective action for releases of hazardous waste or hazardous
        constituents; and

      o §3013 orders seeking monitoring, investigations, analyses,
        and reporting by facilities that the Administrator has deter-
        mined may present a substantial hazard to human health or the
        environment.
    8  For further information on the applicability and scope of CERCLA 106
orders, see the September 8, 1984 memo on the "Use and Issuance of Administra-
tive Orders under §106(a) of CERCLA" from Lee Thomas and Courtney Price.

                                  4-1

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     This chapter will compare these three order authorities and will describe

some of the factors that enforcement officials should consider when selecting

which authority(ies) to use to compel a specific remedy.


4.1  Comparison of §3008(a), §3008(h), and §3013 Orders


     The table on the two following pages presents a comparison of §3008(a),

§3008(h), and §3013 orders with respect to the types of actions that the

orders may compel, the types of situations that may trigger the issuance of

an order, the burden of proof the Agency must satisfy,  whether there are

formal administrative proceedings that must be followed,  and any special

features of the authority (e.g.,  the ability to assess  penalties).  The

section of the chart dealing with §3008(a) orders is divided into the follow-

ing three segments:


           o §3008(a) enforcing Part 265 detection monitoring

           o §3008(a) enforcing Part 265 assessment monitoring

           o §3008(a) enforcing Part 270 requirements.


     4.1.1  Actions the Orders May Require


     As shown in Table 4.1, a §3008(a) order enforcing  Parts 265 and 270 can

be used to require the following  general categories of  ground-water-related

activities:


           o a thorough hydrogeologic characterization  of the site;

           o design and installation of a well network  capable of
             immediately detecting contamination from the facility;

           o specification of well drilling and development methods
             as well as casing materials;


                                  4-2

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        o  sampling for any parameter listed in Appendix VII or VIII of
           Part 261 or Appendix III of Part 265, or specified in §265.92
           (chloride, iron, manganese, phenols, sodium, sulphate, pH, specific
           conductance, total organic carbon, and total organic halogen); and

        o  a design of the ground-water monitoring system that would be
           operated after the permit is issued.


     Section 3008(h) and §3013 orders can in many cases be used to obtain

the same baseline injunctive relief available under §3008(a).  More signifi-

cantly, orders issued under §3008(h) and §3013 may be used to address contam-

ination of media other than ground water and releases from solid waste manage-

ment units.  Further, §3008(h) can be used to go beyond the investigation

and monitoring stage to require actual clean up of releases into the environ-

ment.


     One caution with respect to §3013 and §3008(h) orders is that they may

compel only those actions that are needed to investigate or address a release

of hazardous waste or hazardous constituents [§3008(h)j or a substantial

hazard [§3013].  While there will be cases in which the issuance of orders

under those authorities is appropriate,  it may in some cases be necessary

to issue a simultaneous §3008(a) order to obtain compliance with Part 265/270

requirements.   Further, penalties for violations of Parts 265 and 270 may be

assessed only through issuance of a §3008(a) order.


     4.1.2  Conditions for Order Issuance


     §3008(a)  Orders


     A §3008(a) order may be issued only for violation of one or more Subtitle C

requirements.   Therefore,  when enforcement personnel and the permit writer
                                  4-5

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determine a facility's ground-water monitoring program to be technically

inadequate, enforcement personnel should determine whether any of the technical

inadequacies constitute violations of Part 265 Subpart F or Part 270.9


     In some cases the regulations are specific as to what findings of fact

would indicate violations.   For example, if an owner/operator has installed

only two downgradient wells, the facility is clearly out of compliance with

§265.91(a)(2) of the regulations, the section that requires installation of

at least three downgradient wells.  Likewise, if a facility does not have

some of the records specified in the regulations (e.g., an assessment outline),

or has not performed some of the required analyses, then the owner is clearly

in violation.  The decision concerning the existence of a violation becomes

more involved when it is based upon evaluating the adequacy of a facility's

ground-water monitoring system beyond the minimum requirements.


     In great part, the heightened level of analysis required to evaluate

the overall adequacy of a system evolves from the regulations' reliance on

broad performance standards.  Given the great variability between sites in

terms of wastes handled, hydrogeology, and climate, it is impossible to

design a regulatory system that defines for all cases exactly what constitutes

an adequate ground-water monitoring program.  As a result, the Agency relies

on performance standards to define "adequate."
     9 As cited, herein, references to Part 265,  Subpart F and Part 270 include
requirements of authorized State programs.
                                  4-6

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    The performance-oriented provisions of Subpart F set high standards for




interim status ground-water monitoring systems, and enforcement personnel




should not underestimate the power and applicability of this language.  For




example, even though the regulations establish a minimum of one background




monitoring well, a single well is seldom sufficient because owner/operators




must design their systems to meet the background-well performance standard




listed in §265.91(a)(1).  Section 265.91(a)(l) requires owner/operators to




install a sufficient number of wells at appropriate locations and depths to




yield samples representative of background water quality not affected by the




facility.  If a facility's well array does not meet this standard, the owner/




operator is out of compliance with the regulations.  Figure 4.2 summarizes




the Part 265 and Part 270 performance standards relating to ground-water




monitoring.







     Figure 4.3, on pages 4-9 through 4-14, illustrates in greater detail




the relationship between certain technical inadequacies of ground-water




monitoring programs and the regulatory performance standards of RCRA.  The




left-hand side of the table lists a series of standards that must be met in




order to meet the the performance standards summarized in Figure 4.2 (e.g,,




background-well samples must be unaffected by the facility).  The middle




column includes examples of technical inadequacies that could prevent a




system from meeting the left-hand standards and therefore could represent a




violation of one or more of the performance standards (e.g., failure to




consider flow paths of dense immiscibles when locating background wells).




Finally, the right-hand column lists for each technical inadequacy the




performance standard(s) that may have been violated.
                                  4-7

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                                      FIGURE 4.2

                         GROUND-WATER PERFORMANCE STANDARDS
                                  PARTS  265 and 270
   CITATION
                       STANDARD
 S265.90(a)
 the owner/operator of  a land disposal facility must  implement a
 ground-water monitoring program  "capable of determining the facility's
 impact on the quality of ground  water in the uppermost aquifer
 underlying the facility,..."  (emphasis added)
 §265.91(a)
 a ground-water nonitoring  system  "must be capable of yielding
 ground-water samples for analysis..."
 §265.91(a)(l)
 the number,  locations,  and depths of background ironitoring wells
 must be "sufficient  to  yield  ground-water samples that are:

      (i)   Representative of background ground-water quality  in the
           uppernost  aquifer near the facility; and
     (ii)   Not affected  by the facility..."
 §265.91(a)(2)
 the number, locations,  and depths of downgradient monitoring wells
 must ensure that they "immediately detect any statistically significant
 amounts of hazardous waste or^ hazardous waste constituents that
 migrate from the waste management area to the uppernost aquifer."
         (emphasis added)
§265.93(d)(4)
§270.14(c)(2)
an assessment monitoring plan must be capable of determining:

    "(i) Whether hazardous waste or hazardous waste constituents
         have entered  the ground water;
    (ii) The rate and  extent of migration of hazardous waste or
         hazardous waste constituents in the ground water..."

the Part B applicant must submit, among other things, an  "identifica-
tion of the uppermost  aquifer and aquifers hyiraulically  interconnected
beneath the facility property,  including ground-water flow direction
and rate, and the basis for such identification  (i.e., the informa-
tion obtained from hydrogeologic investigations of the facility
area)." (emphasis added)
S270.14(c)(4)
the Part B applicant must include  in  the  submittal a  "description of
any plume of contamination that  has entered  the ground water  from a
regulated unit at the time that  the application was submitted  that:

     (i)  delineates the extent  of the plume...,
    (ii)  identifies the concentration of each Appendix VIII...
          constituent...throughout the plume..."  (emphasis  added)
                                           4-8

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                                   FIGURE 4.3
    RELATIONSHIP OF TECHNICAL INADEQUACIES TO GROUND-WATER
                         PERFORMANCE STANDARDS
Examples of Basic
Elements Required
by Performance
Standards
   Examples of Technical
   Inadequacies that may
   Constitute Violations
1. Uppermost Aquifer must
be correctly identified
2. Ground-water flow
directions and rates must
be properly determined
•  failure to consider aquifers
   hydraulically interconnected to the
   uppermost aquifer
                                    incorrect identification of certain
                                    formations as confining layers or
                                    aquitards
                                    failure to use test drilling and/or
                                    soil borings to characterize sub-
                                    surface hydrogeology
• failure to use piezometers or wells
  to determine ground-water flow
  rates and directions (or failure to
  use a sufficient number of them)

• failure to consider temporal  varia-
  tions in water levels when
  establishing flow directions (e.g.,
  seasonal variations, short-term
  fluctuations due to pumping)

• failure to assess significance of
  vertical gradients when evaluating
  flow rates and directions.
                                  • failure to use standard/consistent
                                    benchmarks when establishing
                                    water level elevations
                                    failure of the O/O to consider the
                                    effect of local withdrawal wells on
                                    ground-water flow direction

                                    failure of the O/O to obtain suffi-
                                    cient water level measurements
Regulatory
Citations
§265.90(a)
§265.91(8X1)
                                    §270.14(c)(2)

                                    §265.90(a)
                                    §265.91(8X1)
                                           (a)(2)
                                    §270.14(cX2)

                                    §265.90(a)
                                    §265.91(a)(1)
§270.14(c)(2)

§265.90(a)
§265.91(a)(1)
                                                                      §270.14(c)(2)

                                                                      §290.90(a)
                                                                      §295.91(a)(1)
                                                                      §270.14(c)(2)
§265.90(3)
§295.91(8X1)
       (a)(2)
§270.14(c)(2)

§265.90(3)
§265.91(8X1)
                                    §270.14(c)(2)

                                    §265.90(a)
                                    §265.91(a)(1)
                                    §265.90(3)
                                    §265.91(8X1)
                                      4-9

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FIGURE 4.3 (continued)
Examples of Basic
Elements Required
by Performance
Standards
   Examples of Technical
   Inadequacies that may
   Constitute Violations
Regulatory
Citations
3. Background wells must
be located so as to yield
samples that are not
affected by the facility
•  failure of the O/O to consider the      §265.90(a)
   effect of local withdrawal wells on      §265.91(a)(1)
   ground-water flow direction

•  failure of the 0/0 to obtain suffi-       §265.90(a)
   cient water level measurements        §265.91(a)(1)

•  failure of the O/O to consider flow      §265.90(a)
   path of dense immiscibles in          §265.91(a)(1)
   establishing upgradient well
   locations

•  failure of the O/O to consider          §265.90(a)
   seasonal fluctuations in ground-        §265.91(a)(1)
   water flow direction

•  failure to install wells hydraulically      §265.90(a)
   upgradient, except in cases where      §265.91(a)(1)
   upgradient water quality is
   affected by the  facility (e.g.,
   migration of dense immiscibles in
   the upgradient direction, mound-
   ing of water beneath the facility)

•  failure of the 0/0 to adequately        §265.90(a)
   characterize subsurface              §265.91(a)(1)
   hydrogeology

•  wells intersect only ground water      §265.90(a)
   that flows around facility              §265.91 (a)(1)
4. Background wells must
be constructed so as to
yield samples that are
representative of in-situ
ground-water quality
•  wells constructed of materials that
   may release or sorb constituents
   of concern

•  wells improperly sealed—con-
   tamination of sample is a concern

•  nested or mulitple screen wells
   are used and it cannot be
   demonstrated that there  has been
   no movement of ground  water
   between strata

•  improper drilling methods were
   used, possibly contaminating the
   formation

•  well intake packed with materials
   that may contaminate sample
§265.90(a)
§265.91(a)

§265.90(3)
§265.91(a)
§265.91 (c)

§265.90(a)
§265.91 (a)(1)
§265.91 (a)(2)
                                                                         §265.90(3)
                                                                         §265.91(3)
                                                                         §265.90(3)
                                                                         §265.91(3)
                                                                         §265.91(C)
                                         4-1

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 FIGURE 4.3 (continued)
Examples of Basic
Elements Required
by Performance
Standards
   Examples of Technical
   Inadequacies that may
   Constitute Violations
Regulatory
Citations
Background wells must be
constructed so as to yield
samples that are represen-
tative of in-situ ground-water
quality, (continued)
•  well screens used are of an inap-      §265.90(a)
   propriate length                     §265.91 (a)(1)
                                     §265.91 (a)(2)

•  wells developed using water other      §265.90(a)
   than formation water                 §265.91 (a)

•  improper well development            §265.90(a)
   yielding samples with suspended      §265.91 (a)
   sediments that may bias chemical
   analysis

•  use of drilling muds or nonforma-      §265.90(a)
   tion water during well construction      §265.91 (a)
   that can bias results of samples
   collected from wells
5. Downgradient monitoring
wells must be located so as
to ensure the immediate
detection of any contamina-
tion  migrating from the
facility
6. Downgradient monitoring
wells must be constructed
so as to yield samples that
are representative of in-situ
ground-water quality
•  wells not placed immediately adja-    §265.90(a)
   cent to waste management area      §265.91(a)(2)

•  failure of O/O to consider poten-      §265.90(a)
   tial pathways for dense              §265.91(a)(2)
   immiscibles

•  inadequate vertical distribution of     §265.90(a)
   wells in thick or heavily stratified      §265.91(a)(2)
   aquifer

•  inadequate horizontal distribution     §265.90(a)
   of wells in aquifers of varying        §265.91(a)(2)
   hydraulic conductivity

•  likely pathways of contamination      §265.90(a)
   (e.g., buried  stream channels,        §265.91(a)(2)
   fractures, areas of high
   permeability) are not intersected
   by wells

•  well network covers uppermost       §265.90(a)
   but not interconnected aquifers       §265.91(a)(2)

   See #4
                                      4-11

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Examples of Basic
Elements Required
by Performance
Standards
Examples of Technical
Inadequacies that may
Constitute Violations
Regulatory
Citations
7. Samples from
background and down-
gradient wells must be
properly collected and
analyzed
failure to evacuate stagnant water
from the well before sampling
                                     failure to sample wells within a
                                     reasonable amount of time after
                                     well evacuation
                                   •  improper decisions regarding
                                      filtering or non-filtering of samples
                                      prior to analysis (e.g., use of filtra-
                                      tion on samples to be analyzed
                                      for volatile organics)

                                   •  use of an inappropriate sampling
                                      device
                                      use of improper sample preserva-
                                      tion techniques
                                   •  samples collected with a device
                                      that is constructed of materials
                                      that interfere with sample integrity
                                   •  samples collected with a non-
                                      dedicated sampling device that is
                                      not cleaned between  sampling
                                      events

                                   •  improper use of a sampling
                                      device such that sample quality is
                                      affected (e.g., degassing of sam-
                                      ple caused by agitation of bailer)
§265.90(a)
§265.92(3)
§265.93(d)(4)
§270.14(c)(4)

§265.90(3)
§265.92(a)
§265.93(d)(4)
§270.14(c)(4)

§265.90(3)
§265.92(a)
§265.93(d)(4)
§270.14(c)(4)
                                   §265.90(a)
                                   §265.92(a)
                                   §265.93(d)(4)
                                   §270.14(c)(4)

                                   §265.90(3)
                                   §265.92(3)
                                   §265.93(d)(4)
                                   §270.14(c)(4)

                                   §265.90(3)
                                   §265.92(3)
                                   §265.93(d)(4)
                                   §270.14(c)(4)

                                   §265.90(3)
                                   §265.92(3)
                                   §265.93(d)(4)
                                   §270.14(c)(4)

                                   §265.90(3)
                                   §265.92(3)
                                   §265.93(d)(4)
                                   §270.14(c)(4)
                                       4-12

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FIGURE 4.3 (continued)
   Examples of Basic
   Elements Required
   by Performance
   Standards
   Examples of Technical
   Inadequacies that may
   Constitute Violations
Regulatory
Citations
   Samples from background
   and downgradient wells
   must  be properly collected
   and analyzed  (continued)
•  improper handling of samples
   (e.g., failure to eliminate
   headspace from containers of
   samples to be analyzed for
   volatiles)

•  failure of the sampling plan to
   establish procedures for sampling
   immiscibles (i.e., "floaters" and
   "sinkers")

•  failure to follow appropriate
   QA/QC procedures
                                        failure to ensure sample integrity
                                        through the use of proper chain-
                                        of-custody procedures
                                        failure to demonstrate suitability of
                                        methods used for sample analysis
                                        (other than those specified in
                                        SW-846)

                                        failure to perform analysis in the
                                        field on  unstable parameters or
                                        constituents (e.g., pH, Eh, specific
                                        conductance, alkalinity, dissolved
                                        oxygen)

                                        use of sample containers that
                                        may interfere with sample quality
                                        (e.g., synthetic containers used
                                        with volatile samples)

                                        failure to make proper use of
                                        sample blanks
§265.90(a)
§265.92(a)
§265.93(d)(4)
§270.14(c)(4)
§265.90(3)
§265.92(3)
§265.93(d)(4)
§270.14(c)(4)

§265.90(3)
§265.92(3)
§265.93(d)(4)
§270.14(c)(4)

§265.90(3)
§265.92(3)
§265.93(d)(4)
§270.14(c)(4)

§265.90(3)
§265.92(a)
§265.93(d)(4)
§270.14(c)(4)

§265.90(a)
§265.92(3)
§265.93(d)(4)
§270.14(c)(4)
                                     §265.90(3)
                                     §265.92(3)
                                     §265.93(d)(4)
                                     §270.14(c)(4)

                                     §265.90(a)
                                     §265.92(3)
                                     §265.93(d)(4)
                                     §270.14(c)(4)
                                          4-13

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Examples of Basic
Elements Required
by  Performance
Standards
Examples of Technical
Inadequacies that may
Constitute Violations
Regulatory
Citations
8. In Part 265 assessment
monitoring the O/O must
sample for the correct
substances
9. In defining the Appendix
VIII makeup of a plume the
O/O must sample for the
correct substances

10. In Part 265 assessment
monitoring and in defining
the Appendix VIII makeup of
a plume the O/O must use
appropriate sampling
methodologies
11.  Part B applicants who
have either detected con-
tamination or failed to imple-
ment an adequate part 265
GWM program must deter-
mine with  confidence
whether a plume exists and
must characterize any
plume
failure of the O/O's list of sam-        §265.93(d)(4)
pling parameters to include cer-
tain wastes that are listed in
§261.24 or §261.33, unless ade-
quate justification is provided

failure of the O/O's list of sam-        §265.93(d)(4)
pling parameters to include
Appendix VII constituents of all
wastes listed under §§261.31 and
261.32, unless adequate justifica-
tion is provided

failure of the O/O's list of sam-        §270.14(c)(4)
pling parameters to include all
Appendix VIII constituents, unless
adequate justification  is provided

failure of sampling effort to iden-      §265.93(d)(4)
tify areas outside the  plume          §270.14(c)(4)

number of wells was insufficient       §265.93(d)(4)
to determine vertical and horizon-      §270.14(c)(4)
tal gradients in contaminant
concentrations

total reliance on  indirect methods      §265.93(d)(4)
to characterize plume (e.g., elec-      §270.14(c)(4)
trical resistivity, borehole
geophysics)

failure of O/O to implement a          §270.14(c)(4)
monitoring program that is
capable of detecting the existence
of any plume that might emanate
from the facility

failure of O/O to sample both          §270.14(c)(4)
upgradient and downgradient
wells for all Appendix VIII
constituents

See also items #1, #2
                                    4-14

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     The technical inadequacies in Figure 4.3 are not necessarily violations




in all cases.  They are violations only when they result in a failure of the




facility to meet one or more of the performance standards.  Further, the




list of technical inadequacies is not meant to be exhaustive.  To a certain




degree, the decision as to whether a facility's monitoring program is adequate




must be made on a case-by-case basis.






     §3013 Orders






     Section 3013 orders may be issued to a facility only when the Admini-




strator determines that the presence or release of hazardous waste at the




facility may present a substantial hazard to human health or the environment.




The facility need not be violating RCRA regulations to qualify for action




under §3013.






     Actual physical evidence of contamination is not necessary to support a




§3013 order.  In the case of a facility that has not conducted any ground-water




monitoring activities, the potential for release of hazardous waste, the




nature of the site's underlying hydrogeology, and the proximity of an aquifer




or populated area will usually be sufficient, with expert opinion, to support




a §3013 order. In some cases, the Region may wish to use §3007 authority to




sample one or more wells at a facility in order to provide direct evidence




of a release.  Given that direct evidence is often unnecessary to establish




the applicablity of §3013, the Region should probably avoid direct sampling




unless it is confident that existing wells will intersect the suspected




plume.  Guidance issued September 26, 1984 provides further discussion of




the grounds for issuance of §3013 orders.  (See memo from Courtney Price and
                                 4-15

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Lee Thomas entitled, "Issuance of Administrative Orders Under Section 3013




of the Resource Conservation and Recovery Act").






     §3008(h) Orders






     Section 3008(h) of RCRA provides that the Administrator may issue an




order or file a civil suit requiring corrective action or other appropriate




response measures whenever (s)he determines that there is or has been a




release of hazardous waste into the environment.  Section 3008(h) actions are




not limited to violations of RCRA.






     As described in the September 1985 draft guidance on the scope and use




of §3008(h), the Agency is interpreting the term "release" to include any




spilling, leaking, pumping, pouring, emitting, erupting, discharging, inject-




ing escaping, leaching, dumping, or disposing into the environment.  To show




that a release has occurred, the Administrator does not necessarily need




sampling data.  Such evidence as a broken dike at a surface impoundment




should also support a determination that a release has occurred.  In some




cases, information on the contents of a land disposal unit, along with infor-




mation on the site hydrogeology and the design and operating characteristics




of the facility may be enough for an expert to conclude that a release has




occurred.






   Section 3008(h) orders (and civil suits) may be used to address releases




not only to the ground water, but to other media as well.  The draft §3008(h)




guidance states that the authority covers releases of hazardous wastes into
                                 4-16

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surface water, air, the land surface, and the sub-surface strata.  The term




"hazardous waste" is not limited to those wastes listed or identified in




40 CFR Part 261.  For §3008(h) purposes, the term hazardous waste also




includes the hazardous constituents identified in Appendix VIII of Part 261.









4.1.3  Formal Administrative Proceedings






     Orders issued and penalties assessed under §3008(a) are subject to




formal administrative proceedings.  Section 3008(a) proceedings are governed




by 40 CFR Part 22.  (See Appendix B for a diagram of the process).  The




Agency has not yet established the proceedings to be followed when issuing




§3008(h) orders.






     Part 22, which governs the issuance of §3008(a) orders, sets out a




process that affords a respondent the opportunity to request a hearing on




the violation, the penalty, and the remedy proposed by the Agency.  Following




any such hearing, the Administrative Law Judge will issue an Initial Decision




that includes a proposed Final Order and may include a proposed penalty.  At




that point the respondent has 20 days in which to appeal the Initial Decision




to the Administrator.  If an appeal is not made within this time period the




order becomes final and non-appealable 45 days after issuance of the Initial




Decision.






     Section 3013 orders are not subject to any formal administrative




proceedings.
                                 4-17

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4.2  Selection Among Order Authorities






     There are a number of factors that should be considered when deciding




which order authority(ies) to invoke.  The enforcement staff should consider




first which order authorities are applicable to the actions, inactions, or




conditions involved.  Next, the Region should consider which of the applicable




authorities provide a legal basis for requiring the remedy that the Region is




seeking, including the assessment of penalties.  Figure 4.1 may be consulted




for a general listing of the activities that can be sought under each authority.






     In most cases, there will be several options that meet the tests of




applicability and coverage of the desired remedy.  The enforcement options




can be further narrowed by considering: I) the strength of the evidence in




support of each type of order; 2) the elements that must be established and




whether they refer to regulations or must be established de novo; 3) the




amount of time that is likely to pass before compliance is achieved; and 4)




any complications that might arise from using certain combinations of




authorities.






     When estimating the amount of time that may pass before compliance




with a §3008(a) order is achieved, the Regions should assess the probability




of the facility appealing the order.  This is particularly important where




action needs to be taken quickly in order to halt or avoid a hazard or




endangerment.  If the facility is likely to challenge a §3008(a) order




in the District Court, the Agency might elect to file a civil suit seeking




preliminary injunctive relief or to issue a §3013 order (if the §3013 test




could be met).   Alternatively, the Agency could take action itself to
                                 4-18

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mitigate an immediate threat to public health or the environment under




CERCLA §104.






     When contemplating using two authorities to compel different aspects of




the desired remedy, enforcement officials should keep in mind the different




procedures that accompany each order.  For instance, there may be cases in




which a Region would consider issuing simultaneous §3008(a) and §3013 orders:




a §3008(a) order to compel proper well placement and assess penalties and a




§3013 order to compel sampling for constituents not listed in Parts 260-270.




While simultaneous issuance of these orders is acceptable, the Region should




be aware that one order is subject to administrative hearings and the other




is not; therefore, appeal of the §3008(a) order may delay the full implemen-




tation of the remedy.






     In general, a §3008(a) order enforcing Parts 265 and 270 and assessing




penalties will be the most practical enforcement option.  Such an order can




be used to attain nearly any desired improvement to a ground-water monitoring




program.  It can also be used, as noted in Section 1.2.1, to require a facility




to sample the ground water for constituents listed in Appendix VIII of Part 261.






     Section 3013 and §3008(h) orders also have several common features that




make them particularly attractive in certain circumstances.  Both order




authorities may be used to address contamination of media other than ground




water.  For example, either order could be used to address facilities with




both ground-water and air problems.  Moreover, unlike §3008(a) orders,




§3008(h) and §3013 orders are not bound by the ground-water monitoring regimen




specified in the regulations.  Therefore, the Agency has more flexibility in
                                 4-19

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specifying monitoring parameters and sampling frequencies when issuing §3013




and §3008(h) orders.






    Each order authority also has unique features that may make it particu-




larly appropriate for certain situations.  Section 3013, for example, grants




the Agency the authority to perform investigatory activities and recover




costs later if a respondent is incapable of or refuses to perform the neces-




sary actions.  Section 3008(h) does not provide for cost recovery, but can




be used to compel facilities to go beyond the investigation stage and take




corrective action if necessary.  In addition, §3008(h) orders can be used




to address past releases from solid waste management units and contamination




extending beyond the facility boundary.
                                 4-20

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                                  CHAPTER 5




         FASHIONING A REMEDY AND DEVELOPING THE ENFORCEMENT STRATEGY
     The first and perhaps most important step in developing an enforcement




action for a facility with ground-water monitoring problems is fashioning an




appropriate remedy.  Only after outlining the desired remedy can the Region




design an enforcement strategy that will best achieve the desired results.







     This chapter will describe several scenarios involving problem monitoring




programs and, using one common scenario as an example, will illustrate some




of the principles that enforcement officials should consider when designing




technical remedies.  Then, using the same violator as an example, the chapter




will design an enforcement strategy to compel the model remedy.







5.1  Types of Violators







     Each ground-water case will,  of course, have unique features.   It is




possible, however, to group RCRA ground-water violators into several broad




categories that characterize the status of the facility at the time of enforce-




ment review.  Figure 5.1 outlines  one possible scheme that divides  facilities




into groups based on a combined evaluation of their Part 265 system and the




adequacy of their permit application.  This scenario will be used later in




Figure 5.3 to illustrate possible  remedies and enforcement strategies for




facilities with different types of ground-water violations.







     The assumption in this scheme is that all the facilities listed are in




violation of Part 270 because they did not generate the information necessary




for permitting.  In some cases, this deficiency derives from inadequate







                                  5-1

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  compliance, with Part 265 (facilities that have  inadequate 265 detection

  systems, for example, will not have generated the  information necessary to

  determine whether the facility should be permitted under detection monitoring,

  compliance monitoring, or corrective action).  In  other cases,  facilities

  may have complied with 265, but not have completed all activities  required by

  the permit application regulations (e.g., the facility performed some  assessment

  activities based on Appendix VII,  but did not sample  for Appendix  VIII as

  required by §270.14(c)(4)).
  FIGURE 5.1
                          Violator Classification  Scheme
Scenario
Facility Status
Possible Sources of Inadequacy
1.     No statistically significant change
       in Part 265 indicator parameters;
       Physically adequate detection network;
       Agency has reason to believe there
       Is contamination.
                                 Part 265 indicator parameters are no
                                 adequate to detect type of leachate
                                 expected from facility; site hydro-
                                 geology or facility's  engineering
                                 design puts facility at high risk
                                 of leaking.
       No statistically significant  change
       in Part 265 indicator parameters;
       Inadequate Part 265 detection
       system.
                                 Well placements made based on insuf-
                                 ficient hydrogeologic assessment;
                                 Too few wells;  Inappropriate sampling
                                 device; Wells not properly developed,
                                 etc.
       Statistically significant change in
       Part 265 indicator parameters;
       Inadequate Part 265 detection system;
       Inadequate Part 265 assessment.
                                 Owner/operator used only indirect
                                 techniques to assess plume.
       Statistically significant change in
       Part 265 indicator parameters;
       Adequate Part 265 assessment;
       Inadequate permit application.
                                    5-2
                                 Owner failed to identify all Appendix
                                 VIII constituents in ground water;
                                 Owner based concentration limits
                                 on insufficient background sampling;
                                 Owner failed to submit a feasibility
                                 plan for corrective action, etc.

-------
5.2  Profile of a "Transition-Period" Violator







     During the transition period between interim status and permitting, the




Agency envisions encountering a considerable number of facilities of the type




described in Scenario 2 (Figure 5.1).  The Agency's experience to date has




indicated that in certain cases, owner/operators have installed monitoring




networks based on only a limited understanding of the hydrogeology underlying




their site.  Monitoring wells have been located based on an evaluation of




local topography and, to the extent possible, evaluation of existing building




foundation borings.  A considerable number of owner/operators have not performed




the type of detailed hydrogeologic site assessment the Agency considers




essential for the design of any ground-water monitoring system.  Even fewer




have kept the type of well construction and design records the Agency needs




to evaluate the adequacy of the physical well network already in place.







     As a result, EPA expects to encounter owner/operators who consider




themselves in compliance but who can not provide the background information




and documentation minimally necessary to substantiate the adequacy of




their Part 265 detection system.  Without such information, the Agency will




not be able to decide whether a facility's detection system is or is not




capable of detecting contamination and hence whether the facility should be




permitted under detection monitoring, compliance monitoring or corrective




action.  Not having detected a change in indicator parameters, however,




the facility most likely will have applied for a detection monitoring permit,




considering itself exempt from the assessment requirements of §270.14(c)(4).
                                  5-3

-------
     A typical "transition" facility, therefore,  could be characterized as

follows:
       o  the facility has failed to adequately characterize the hydro-
          geology underlying its site;

       o  therefore, the facility's well placements are inaccurate;

       o  the facility has sampled for the Part 265 indicator parameters.
          No statistically significant increases have been detected in
          existing downgradient wells;

       o  the facility's Part B is due.   The facility has submitted a
          summary of its interim status  monitoring data and has proposed
          an expanded list of indicator  parameters for Part 264 monitoring.
          The permit application includes procedures for establishing back-
          ground values for these parameters,  but does not include actual
          background values based on pre-permit sampling.
     This chapter will use the above scenario to illustrate some of the

principles enforcement officials should consider when designing remedies for

facilities during the interim status to permitting transition period.   The

chapter uses Scenario 2 as its point of departure because a facility that

has not detected contamination under interim status presents the greatest

challenge to enforcement officials.  Moreover, the remedies appropriate for

the other scenarios presented in Figure 5.1 are but a variation of the remedy

outlined in the following section for the facility described in Scenario 2.


     Table 5.5 at the end of the chapter summarizes the variations on the

remedy appropriate for each of the other listed scenarios.


5.3  Outline of the Remedy


     When faced with a facility that has a technically inadequate detection

monitoring system, enforcement and permitting officials must consider first
                                  5-4

-------
what makes sense for a facility to do in light of the facility's past and




future monitoring obligations.  By this point in the program, an interim




status facility should have installed a fully competent detection monitoring




system, determined with confidence whether there was a statistically signifi-




cant indication of ground-water contamination, and fully characterized any




plume for both Appendix VII and VIII constituents (if contamination were




detected).  If a facility has not successfully completed even the first




step - the installation of a competent detection system - it cannot be




allowed to begin the entire sequence anew.  Proceeding from the beginning




would mean upgrading the detection system and sampling for one year to




establish background before even the first determination of contamination




is made.






     As the time line in Figure 5.2 points out, proceeding through this




entire sequence could take up to two and one-half years.  This approach




would lead to unacceptable delays in the permitting process and would




penalize those facilities who had complied with the program all along.




In effect, "starting over" would merely allow facilities that had avoided




the costs of complying in the past, to delay the costs of full compliance




for an additional period of time.






     Instead,  such facilities should be required to make an accelerated




determination of whether or not contamination has occurred.  This determina-




tion can then be used to decide what additional actions, if any, the applicant




must perform to meet his/her permit application requirements.
                                  5-5

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     Before a determination of leakage can be made, the facility must install




a monitoring network capable of detecting contamination.  In general, this will




require such facilities to perform additional site characterization and then,




based on the results, expand or replace their existing monitoring network.




Once a competent detection network is in place, the facility is in a position




to determine whether or not contamination has occurred.







     The Agency suggests that the determination of whether contamination has




occurred be made based on a comparison of upgradient and downgradient values




obtained for an expanded list of indicator parameters.  The indicator para-




meters should be selected based on the specifics of the site and should




include constituents that would be expected to be at the leading edge of any




plume of contamination (see Section 5.4.2).  The comparison should be based




on the mean of pooled data obtained through accelerated sampling over a short




period of time.  The plan for this determination should be designed to con-




clusively confirm or refute contamination in the shortest period of time




possible.







     If contamination has occurred, the facility owner must proceed to charac-




terize the plume and, based on the results, apply for either an operating or




post-closure permit that includes compliance monitoring and/or corrective




action.  If contamination has not occurred (i.e. the results of interim




status monitoring were correct even though the detection system was not fully




competent), then the facilty would apply for a permit as a detection monitoring




facility.
                                  5-7

-------
     Thus the preferred technical response for a facility that has not triggered

under detection monitoring but has an inadequate Part 265 detection system is

as follows:

        1)  Conduct a detailed assessment of the site's
            hydrogeology (fill in gaps in the facility's
            current understanding of the site's subsurface).

        2)  Install a monitoring network (or modify/expand
            an existing system) to meet the objectives of Parts
            265/264 detection monitoring.

        3)  Sample for an expanded list of indicator parameters.

        4)  Determine whether contamination has occurred based
            on a comparison of upgradient and downgradient well
            samples obtained over a short period of time
            (accelerated sampling).

        5)  If contamination is confirmed, begin characterizing
            the plume based on monitoring of Appendix VIII
            constituents.

        6)  Sample to establish background for all Appendix VIII
            constituents detected in ground water.

        7)  If downgradient Appendix VIII values are significantly
            greater than background values, have facility develop
            corrective action plan and apply for corrective action
            permit.10

            If downgradient Appendix VIII values are lower than back-
            ground, have facility submit a corrective action  feasibility
            studyI* and apply for a compliance monitoring permit.
    10 Note that if the permit is not likely to be issued quickly,  the Agency
may wish to initiate corrective action while the facility is still  in interim
status.  Several authorities are available to compel such corrective action,
including §3008(h), §7003 and Section 106 of CERCLA.  Further,  in some
instances, the Agency may choose to conduct a response action under the
authority of CERCLA §104.

    11 Section 270.l4(c)(7) requires applicants to submit a corrective action
feasibility study when applying for a compliance monitoring permit.  The study
must include sufficient information to predict what type of corrective action
(e.g., trench recovery, pumping and treatment) would be appropriate if reme-
dial work proved necessary at that site.  It is not meant to be a fully
developed plan for corrective action; such a plan must be developed pursuant
to §264.99(i)(2) if the facility ever exceeds its ground-water protection
standard.

                                  5-8

-------
     The schedule of achieving the above remedy will of course depend on the




particulars of the site involved, especially the complexity of the site's hydro-




geology.  While it is impossible to predict how long it will take (or should




take) to accomplish each step, the sequence of monitoring events in this remedy




should be significantly shorter than the sequence laid out in the regulations.






     As illustrated in Figure 5.3, the remedy recommended in this document




in effect eliminates the collection of a year's worth of background data and




condenses the monitoring required by Part 265 assessment [primarily Appendix




VII] and §270.I4(c)(4) [Appendix VIII] into one plume characterization phase.




Now confirmation (or denial) of leakage can be accomplished through accelerated




sampling over a period of weeks or months rather than taking over a year.






5.4  Discussion of the Remedy






   The basic elements of the remedy are the design and installation of a




competent detection monitoring well network; determination of whether or not




leakage has occurred based on sampling for an expanded list of parameters;




and the fulfillment of all applicable Part 270 informational requirements.




The following section will describe briefly certain factors enforcement




officials should keep in mind when developing each aspect of the remedy.




Later sections will explore the order and regulatory authorities available




to compel each of the outlined activities.






     5.4.1  Design and Installation of a Competent Monitoring Network






     The facility owner should be required to upgrade his/her existing network




to meet the detection standards of Part 265.  The reader should note that if
                                 5-9

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an owner/operator's hydrogeologic data submitted pursuant to §270.l4(c)(2) is

inadequate, it is likely that the facility's detection monitoring well network

ts inadequate as well.  The reader should also note that since the the design

and construction standards for a Part 265 system are essentially the same as

those required by Part 264 (see Chapter 3), the network installed for the

determination of leakage proposed in the model remedy should serve equally

well as the facility's Part 264 detection monitoring system if no plume is

found.


     5.4.2  Confirmation of Leakage Based on Expanded Sampling


     Central to the determination of leakage proposed in the model remedy is

the development of a list of meaningful indicator parameters.  When selecting

parameters, enforcement officials should not limit themselves to the four

indicators listed in §265.90.12 These parameters were selected as the best

indicators available to detect a broad spectrum of possible leachates.

Because the interim status regulations were meant to be self-implementing,

Part 265 detection monitoring could not rely on waste-specific indicators

selected for each facility.  As a result these parameters are limited in

their ability to indicate contamination soon after leakage.


     The Part 265 indicator parameters are limited in three ways.  First,

the Part 265 indicator parameters are subject to sources of  natural variation

that can mask the presence of low levels of contamination.   There are many

natural sources of variation in pH,  for example, that could obscure changes
     *2  See Section 5.5.2 for an explanation of the authorities available
to compel sampling for a broader list of parameters.
                                 5-11

-------
in this parameter caused by leachate.  Changes in levels of a specific para-




meter such as benzene, however, are not generally subject to such background




"noise."  Second, with the exception of TOX (which can be detected at below




20 ppb), the lower detection limit of the other parameters is not sufficiently




sensitive to register some changes in water chemistry that may represent




leakage.  Finally, because the Part 265 indicator parameters are surrogate




measures, increases in a particular chemical constituent do not necessarily




cause an equivalent change in an indicator parameter.  A 5 mg/1 change in




lead, for example, would only initiate a very small change in specific con-




ductance (if any).  The same increase in concentration would initiate a




significant change, however, if the facility were sampling for lead itself.






     Therefore, enforcement officials should select indicator parameters that




are based on the chemical composition of the facility's waste.  The enforcement




official should have the facility identify both the hazardous and non-hazardous




constituents of the facility's waste, including any constituents likely to




form as a result of chemical reactions occurring in the facility or in the




leachate as it migrates through the subsurface.  Then the owner/operator




should identify those constituents that can be considered the most mobile and




persistent in the unsaturated and saturated zones beneath the facility.  The




enforcement official should then select those parameters that individually




or as a group (e.g. TOX) can provide the most reliable indication of leakage.




Special attention should be given to whether the parameter is easily detected




in water and to the variability of the parameter in background water.  If




background concentrations of a potential indicator parameter are sufficiently




high or exhibit a high degree of variability, the arrival of low or moderate




concentrations of leachate may be masked.






                                 5-12

-------
     The list of parameters finally selected should be representative of




constituents at least as mobile as the most mobile hazardous constituent




reasonably expected to be derived from the facility's waste.  Concentrating




on the most mobile constituents will ensure that the arrival of leachate is




detected at the earliest possible time.






     In addition to indicator parameters, enforcement officials should consider




having the facility sample for additional parameters that characterize the




general quality of water at the site (e.g., Cl~, Fe, Mn,  Na+, SO^, Ca+, Mg+,



 +    —3     =
K , NO  , PO^ , silicate, ammonium, alkalinity or acidity).  Baseline data on




the inorganic chemical composition of ground water can provide an important




basis for comparison and planning should the program enter the assessment




phase.  Information on the major anions and cations that make up the bulk of




dissolved solids in water, for example, can be used to determine reactivity




and solubility of hazardous constituents and therefore predict their mobility




under actual site conditions.






     5.4.3  Fulfillment of Applicable Part 270 Requirements






     When designing the remedy, enforcement officials should include elements




that address the facility's information obligations pursuant to Part 270.  If



contamination is confirmed, the facility must generate the remainder of the




information required by §270.14(c)(4),  namely the extent of migration of any




plume and the concentration of all Part 261 Appendix VIII constituents present



in the plume.






     Enforcement officials should also ensure that the remedy includes the




collection of background data on all Appendix VIII constituents detected in






                                 5-13

-------
ground water.  For many constituents, these data will be necessary to




establish concentration limits for incorporation into the facilty's ground-




water protection standard.  As described in section 3.2.1, the permit writer




will have to set concentration limits based on the mean of pooled data avail-




able at the time of permitting (unless there is a high temporal correlation




between contaminant concentrations in upgradient and downgradient wells in




which case concentration limits may be established through sampling at the




compliance point).  Therefore, it is in the best interests of both the




facility and the Agency to have sufficient data available at the time of




permitting to accurately characterize the quality of the background water




at the site.






     To guarantee sufficient data, enforcement officials should consider




incorporating in the facility's prescribed remedy an accelerated program of




background sampling for Appendix VIII constituents.  The frequency of sampling




should be dictated by the needs of the statistical test proposed by the facility




for use in compliance monitoring.  The sampling schedule should also consider




the need for establishing seasonal and spatial variation in contaminant levels




if such variation is expected at the site.  Sections 6.3 and 7.3.2 of the




Permit Writer's Guidance Manual provide further guidance on these points.






     In addition, the order should require the submittal of the various




plans and feasibilty studies necessary to establish a compliance monitoring




program or a program for corrective action pursuant to §§270.l4(c)(7) or (8)




(see Section 2.3.2).  By placing these permit application requirements on an




enforceable compliance schedule, enforcement officials can help ensure that




the requirements will be fulfilled in a timely manner.
                                 5-14
                                                                                i

-------
5.5  Application of Enforcement Authorities to the Remedy







     Once the enforcement staff and permit writer devise an appropriate remedy,




the enforcement staff must determine the order and regulatory authorities best




suited to compel the desired actions.  As Section 4.2 on selecting order author-




ities points out, there are a variety of factors enforcement officials must




consider when developing an enforcement strategy.







     When deciding between order authorities, officials must first establish




the applicability of the order to the situation at hand (i.e., does the




situation meet the conditions necessary for the issuance of a particular




order).  Next, the official must consider whether the order can compel all




aspects of the desired remedy.  Where possible, it is advantageous to secure




the entire remedy through a single authority in order to save resources and




avoid the possibility of different appeal procedures.  Finally, enforcement




officials must factor in other relevant concerns such as the facility's




compliance history and whether or not it is important in the instant case to




assess a penalty.  In certain circumstances, features such as the ability to




assess a penalty may become the deciding factor when choosing between order




authorities.






     This section will apply the above principles to the model remedy




developed in this chapter.  It will outline a preferred enforcement strategy




for the model remedy and will note where changes in the remedy could suggest




needed changes in the proposed strategy.  Table 5.5 at the end of the chapter,




summarizes various enforcement strategies for facilities with different




ground-water violations and different technical remedies.
                                 5-15

-------
     5.5.1  Selection of the Order Authority


     Assume that the only information known about the Scenario 2 facility is

that presented in Figure 5.1; namely, the facility is in violation of the

Part 265 ground-water regulations for the following reasons:
     1.  the facility located its wells based on a poor understanding of the
         site's hydrogeology;

     2.  there are too few wells installed;  and

     3.  the owner cannot demonstrate that existing wells were properly
         constructed.
In addition, the facility is in violation of §270.14(c)(4)  because the owner

made no attempt to look for and assess any plume beneath the facility before

the facility's Part B due date passed.


     Based on the above information alone, the most appropriate order author-

ity for compelling the model remedy of this chapter would be a §3008(a) order

enforcing Parts 265 and 270.  A §3008(a) order is the authority of choice

for three reasons.  First, the condition for issuing a §3008(a) order has

already been met - the facility is clearly in violation of  the regulations.

To use either of the other authorities, the Agency may have to expend addi-

tional resources to collect evidence that there may be a substantial hazard

to public health or the environment [§3013] or a release of hazardous waste

or constituents into the environment [§3008(h)].


     Second, as the following section will explain, the entire remedy can be

compelled using a §3008(a) order citing relevant sections of Parts 265 and

270.  The remedy as presently conceived focuses exclusively on evaluating
                                 5-16

-------
the impact of the facility on ground water; hence, an order that can address




other media, such as a 3013 or 3008(h) order, is not needed.  Further, in




this particular case, there is no reason to suspect that the threat posed by




potential ground-water contamination is so compelling as to require corrective




action prior to permitting.  Therefore, it is not essential to use an order




that can accommodate clean up of ground water during interim status.  Of




course, if additional evidence collected during plume characterization




indicated that clean up should be pursued immediately, a §3008(h) order could




be issued subsequent to the initial §3008(a) action.






     Finally, a §3008(a) order has the added advantage that it can be used to




assess penalties.  Given that the facility has been out of compliance for the




entire history of the program, the Agency should exercise its authority to




assess penalties for past and continuing violations including the recovery of




the facility's economic benefit of non-compliance.






     Of course, if the starting scenario were different, the considerations




guiding the selection of an order authority could change significantly.  For




example, if there were evidence of off-site contamination (e.g., a fish kill




in a nearby stream) and the facility were known to delay resolution of pro-




ceedings by exercising every opportunity for appeal, enforcement officials




may decide to postpone the assessment of penalties and immediately issue an




order under §3013, §7003 or CERCLA §106 to avoid the time delay afforded by




the administrative process.  In another case, if a facility were out of




compliance with the ground-water regulations and had significant soil contami-




nation, the Region could use a §3008(h) order to achieve both compliance with
                                 5-17

-------
  the regulations and clean-up of contaminated soil.   The proper way to balance

  the advantages and disadvantages of each order authority can only be determined

  in the context of a particular situation.


       5.5.2  Securing the Model Remedy Through a §3008(a) Order


       As outlined in Figure 5.4, the model remedy derives directly from the

  regulations.  Sections from Part 265 and 270 may be cited to compel

  additional hydrogeologic investigation and the installation of an adequate

  well network.  Section 270.14(c)(4) may be cited to force sampling for an

  expanded list of parameters and to justify the comparison of upgradient and

  downgradient wells based on accelerated sampling.  Finally, relevant sections

  of the Part 270 regulations may be cited to require the collection of back-

  ground data on Appendix VIII constituents and the submission of other plans

  and data necessary for permitting.



  Figure 5.4
       MODEL REMEDY
1.  Fill in gaps in the current understanding
    of the site's hydrogeology
2.  Install a monitoring network (or expand an existing
    system) to meet the objectives of a Part 265/264
    detection system
3.  Sample for an expanded list of indicator parameters:

      Part 265 indicator parameters (TOX, TOC,  pH,  specific
      conductance)
REGULATORY CITES
  §265.90(a)
  §265.91
  §270.14(c)(2)
  §265.91
  §265.92(b)(3)
                                   5-18

-------
  Figure 5.4 (continued)
      Part 265 water quality parameters (Cl,  Fe,  Mn,  Na,
      Phenols, Sulfate)
      Substances with National Interim Drinking Water
      Standards (Appendix III, Part 265)

      Appendix VIII of Part 261
4.  Determine whether contamination has occurred
    based on a comparison of data collected from
    up- and downgradient wells over a short period
    of time.
5.  If contamination is confirmed,  begin assessing the
    plume based on monitoring of Appendix VIII constituents
6.  Sample to establish background for all Appendix VIII
    constituents detected in ground water
7.  Submit data and plans required for either
    compliance monitoring or corrective action
§265.92(b)(2)



§265.92(b)(L)


§270.14(c)(4)


§270.14(c)(4)
§270.l4(c)(4)
§270.14(c)(7)(iv)
§270.14(c)(7)  or
          (8)
       The regulatory cites in this strategy  are  relatively  straight  forward;

  however, the role of §270.14(c)(4) deserves attention.   As  section  2.3.1

  explains,  the Agency may require a facility to  look  for and assess  a plume

  at any facility where the owner/operator's  program of  interim status monitor

  ing has detected a plume or has  failed  to establish  definitively  whether  or

  not a plume exists.


       Under §270.I4(c)(4), the facility  is obligated  to  assess the extent  of

  any plume  and sample for the full complement  of Appendix VIII constituents.
                                   5-19

-------
Therefore, It is within the Agency's authority to require the facility to




begin assessment and full Appendix VIII sampling immediately.  The model




technical remedy, however, limits the scope of sampling to a more manageable




list of indicator parameters until the presence of a plume is confirmed or




refuted.  In effect, the model technical remedy refrains from immediately




exercising the full power of §270.14(c)(4) in order to avoid wasted effort if




indeed the facility has not leaked.









5.6  Variations on the Model Scenario






     This chapter has used the facility described in scenario 2 to illustrate




some of the principles enforcement officials should consider when designing




technical remedies and developing enforcement strategies.   As the scenario




changes, the remedy appropriate for  the situation and the enforcement tools




available to secure that remedy change as well.  Figure 5.5 (at the end of




the chapter) illustrates how the technical remedy and enforcement response




vary based on the status of the facility at the time of enforcement review.






     It is important to note that all proposed remedies include correcting any




deficiencies in the existing detection network even if the facility has already




detected contamination and begun to  characterize the plume.  As described in




the Chapter 2, a sound well network  at the limit of the waste management area




is critical to every phase of ground-water monitoring, from interim status




monitoring to compliance and/or corrective action monitoring.  Therefore, it




makes sense to correct any deficiencies in the interim status detection




system, because these wells will be  used throughout the life of the facility.




Moreover, a system may have detected a plume in one area and still be incapable
                                 5-20

-------
of detecting a plume at some other point.  In such cases, the system should

be upgraded so that it will be capable of detecting future plumes of contam-

ination.


     It is further important to note that where a facility has managed to

detect a statistically significant change in indicator parameters even

though its detection system is inadequate (see Scenario 2 in Figure 5.5),

enforcement officials should require the facility to begin characterizing

the plume downgradient from the triggering well and at the same time perform

additional hydrogeologic evaluation and upgrade the detection network.


     Finally, the technical remedies outlined in this chapter are appropriate

not only for operating units but also for most units that are closed or are

planning to close.  Section 270.l(c) states that units closing after January

26, 1983 must have permits during the post-closure period.13  por units

that accepted hazardous waste after July 26, 1982, the post-closure permit

would include the ground-water monitoring program set out in Part 264 and

the permit application would include the ground-water monitoring data required

under §270.14(c).  Thus, once a closing unit's Part B application is due,

enforcement officials can rely on the same range of enforcement options that

are available to address operating units.
13 in order to implement §3005(i) of the Solid Waste Disposal Act,  as amended,
the Agency intends to propose amending §270.l(c) to make all units  closing
after July 26, 1982 subject to post-closure permits.  Section 3005(i) of the
revised Act makes all units receiving wastes after 7/26/82 subject  to Part
264 ground-water monitoring and corrective action requirements.   Since a permit
is the means by which the Agency implements the Part 264 standards,  the
Agency considers it necessary to revise §270.l(c) in order to make  all units
subject to Part 264 ground-water monitoring and corrective action also subject
to post closure permitting.


                                 5-21

-------
      There are three categories of units that would not currently be subject

to the Part 265/270 program outlined in this chapter.  First,  units that

closed before January 26, 1983 are not required to obtain permits and thus

are not subject to Part 270 requirements [codification rule may roll this

date back to July 26, 1982].  Second,  units that ceased receiving hazardous

waste by July 26, 1982 are not subject to the Part 264 ground-water monitoring

provisions and therefore, in applying  for the permit, would not need to

include the ground-water data required under §270.14(c)(4). Third, no post-

closure requirements apply, and thus no permit or permit application is

currently required for a surface impoundment or waste pile that closes by

removing all hazardous waste and waste residues from the unit,  the under-

lying and surrounding soil, and the ground water.  The Agency  is presently

evaluating whether §3005(i) may require the Agency to make units that clean

closed under Part 265 but received waste after 7/26/82 subject  to post-closure

permitting in order to implement Part  264 ground-water monitoring and corrective

action.


     In all of the above cases, however,  the Part 265 ground-water monitoring

requirements do apply and should be enforced.1^  In the case of a surface

impoundment closing through removal, the Agency/State should ensure that the
14 The successful execution of closure responsibilities (e.g.,  installation of
a cap, run-off and run-on control)  does not absolve  a facility  from its Part 265
ground-water monitoring responsibilities.   Section 265.117  of  the  regulations
states that closed facilities must  comply  with the ground-water monitoring and
reporting requirements of Subpart F for 30 years  after the  date of closure.
Therefore to meet its post-closure  care requirements, a closed  or  closing
facility with an inadequate Part 265 monitoring network would have to upgrade
its system and assess any plume of  contamination  detected during the post-closure
care period.

                                 5-22

-------
closure plan provides for monitoring that is adequate to demonstrate the




absence of hazardous waste in the ground water.  Surface impoundments




generally cannot qualify for closure by removal if any hazardous waste is




present in the ground water; such impoundments must instead close as land




disposal facilities.
                                 5-23

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                                 CHAPTER 6




                             DEVELOPING ORDERS
     The purpose of this chapter is to help enforcement officials ensure that




the ground-water remedy sought by the Agency is in fact executed by the respon-




dent.  The chapter will discuss the importance of specificity in detailing




the desired remedy and various strategies that may be followed in developing




and issuing orders.  The chapter will concentrate exclusively on how to




develop the technical content of compliance orders; it will not address




legal issues related to writing orders or issuing complaints.  Guidance on




such issues is already available in the Compliance/Enforcement Guidance




Manual dated September, 1984 (See especially Chapter 7, "Administrative




Actions: Civil").






6.1  Import .mce of Specificity






     The Agency's experience to date suggests that certain members of the




regulated community have failed to implement a ground-water system capable




of meeting the requirements of Parts 265 and 270.  This is particularly




true with respect to Part 265's broad performance standards and may increase




with respect to Part 270 as Part B applications are filed.  As Section




4.1.2 points out, even though the regulations do not specify in detail how a




system should be designed and operated, the performance language demands a




rigorous program of hydrogeologic investigation, network design, well




construction,  and sampling and analysis.
                                  6-1

-------
     Despite the high standards set by the regulations, certain owner/




operators have ignored this performance language and have installed only




four wells (three downgradient and one upgradient),  in settings whose complex




hydrogeology require a substantially greater number of wells.







     In light of the failure of certain facilities to achieve the high standards




set by the regulations, it is essential that the Agency introduce specificity




into the administrative enforcement process.  In the course of each administra-




tive proceeding there must develop between the Agency and the respondent an




express understanding as to what activities will constitute compliance with




the regulations.  Administative orders that are explicit regarding the Agency's




expectations can help ensure that the actions taken by the owner/operator




will be sufficient to bring the facility into compliance.  Specificity regard-




ing what will be considered appropriate or adequate, can help avoid the




wasted time and effort that results when a respondent performs actions later




deemed inadequate.  It is clearly in the best interest of both parties to




ensure that the facility's first effort to come into compliance meets the




Agency's requirements.







     The Agency can secure this assurance either by reviewing the owner/




operator's plans for coming into compliance before the work is actually




performed or by specifying up front exactly what actions are required of the




respondent.  An order, therefore, can be structured in one of two ways.  If




issued prospectively, an order may be structured around the submittal, and




subsequent Agency review, of individual plans outlining the respondent's




proposed actions for implementing each phase (hereafter referred to as a
                                  6-2
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"phased order").  Alternately, the Agency can issue highly explicit orders




that define technically what the owner/operator must do to come into compli-




ance.







     The next two sections of this document explain the above two types of




order in greater detail.  Both orders place the burden of system design on




the respondent, yet provide the Agency with an opportunity to veto any design




before the system is actually implemented.  When issuing either type of order,




enforcement officials must make clear that notwithstanding compliance with the




order, the respondent remains responsible for compliance and abatement of




any ground-water contamination  A specific provision should be included in




all orders noting that the respondent may be required to take further actions




as necessary to comply with RCRA or other applicable laws.







6.2  Phased Orders for Ground-Water Monitoring Violations







     The concept of phased orders is relatively new to the RCRA program.  As




its name implies, a phased order lays out a series of actions the respondent




must take over time in order to come into compliance.  Each action or phase




is linked to an enforceable compliance schedule and generally includes some




mandatory interaction between the respondent and the Agency.  Most commonly,




each phase will include the development of a plan by the respondent to accom-




plish a specified goal;  the submittal of the plan to the Agency for review,




modification, or approval; and the eventual execution of the plan by the




facility owner.







     A phased order format is especially well suited for addressing ground-




water monitoring violations at hazardous waste facilities.  In many ground-
                                  6-3

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water cases, the nature of the violation is such that neither the facility




nor the Agency knows at the outset exactly what actions will be necessary




and sufficient to bring a facility into compliance.  Many ground-water viola-




tions, for example, derive directly from a facility's lack of understanding




of the hydrogeology beneath their site.  As more information is collected




and interpreted, the steps appropriate for a respondent to take may change.




Developing a technical remedy under such circumstances is, of necessity, a




dynamic process.






     A phased order, however, can accomodate these changes.  By proceeding




in stages, a phased order allows the Agency to structure and guide a facility's




actions without locking the facility or the Agency into a specific remedy




that may prove inadequate.  Moreover, the order provides a mechanism for the




Agency to communicate more specifLcally EPA's expectations regarding various




aspects of the owner/operator's response.  For example, the Agency can set




out in the order the information a hydrogeologic assessment must yield in




order to provide the level of detailed understanding the Agency considers




necessary for the installation of an adequate ground-water monitoring system.




Where the Agency has specific preferences on how certain types of information




should be obtained (e.g., a preference for specific tests or procedures),




enforcement officials can specify the use of the test in the order.   Alter-




nately, an order may list objectives or considerations that an owner/operator




must incorporate into his/her decision-making.  The order might specify, for




example, that the owner/operator must demonstrate in the plan that a pro-




posed sampling device:  1) minimizes the potential for degassing; and




2) minimizes the potential for adsorption and desorption of constituents.
                                  6-4

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     Appendix A includes a sample order that illustrates some of the above

options.  This order is structured around the needs of the "transition

facility" described in Chapter 5; recall that this facility has an inadequate

detection monitoring system and has not detected a significant change in the

Part 265 indicator parameters.  The preferred technical and enforcement

response for such a facility is summarized below.
       Action on the Part of Facility Owner
Enforcement Authority
1) Conduct detailed assessment of site's hydrogeology
   (fill in gaps in current understanding of site's
   subsurface).

2) Install a monitoring network ( modify/expand an existing
   system) to meet the objectives of 265/264 detection.

3) Sample for an expanded list of indicator parameters.

4) Determine whether contamination has occurred by
   comparing upgradient and downgradient well samples
   collected on an accelerated schedule.

5) If contamination is confirmed, begin characterizing
   the plume based on monitoring of Appendix VIII constituents.
 1.  §265.91(a)
     §270.14(c)(2)
 2.  §265.91


 3.  §270.14(c)(4)
     To implement this remedy, the sample order in Appendix A mandates the

execution of six tasks:
       1)  Submittal of a plan to conduct a hydrogeologic assessment of the
           site;

       2)  Submittal of a list of constituents or parameters to be monitored
           for (Note: sampling protocol and well construction materials will
           be dictated by chosen indicator parameters);

       3)  Submittal of proposed monitoring network,  including well locations,
           screening depths,  construction methods,  and design specifications
           (e.g., filter pack material, slot size,  well  diameter);
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       4)  Submittal of a sampling and analysis plan;

       5)  Execution of the plans developed in steps 1, 3, and 4 (following
           Agency approval);

       6)  If contamination is confirmed, submittal of a plan outlining
           proposed assessment activities.
The order combines these tasks into three phases and establishes compliance

deadlines for each phase.  For example, the order requires the owner/operator

to develop and submit the hydrogeologic assessment plan and the list of

parameters by the same date (phase 1).  Next, the order instructs the respon-

dent to complete the assessment and submit the results of the investigation

along with a monitoring network plan and a sampling and analysis plan by the

next compliance date (phase 2).  After EPA approves or modifies these plans,

the order requires the respondent to make the first determination of contami-

nation and submit the results and an assessment plan (if contaminatioa is

confirmed) by the final date (phase 3).


     The sample order combines the required tasks in the above manner for the

purpose of illustration only.  In every case, the logical sequence of events

will be dictated by the particulars of the site.  Enforcement officials must

use professional judgement when deciding which tasks are appropriate, how they

should be combined, and what level of Agency/facility interaction the order

should mandate.


6.3  Technically Specific Orders


     Rather than structure the development of the technical remedy through the

order itself, enforcement officials may prefer to oversee the collection of

background data and the development of a proposed remedy through informal

interaction and negotiations with the facility.  This approach is acceptable


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as long as the work done in preparation of the remedy (e.g., hydrogeologic




assessment activities), and the final terms of the remedy itself (e.g., well




locations, sampling schedules), are set out in a technically-specific order




(usually on consent).   The order may be issued before the wells are installed




and the sampling conducted, or it may be issued afterwards.  If negotiations




become protracted and work is not proceeding expeditiously, however, the




Region should issue the order and place the facility on an enforceable




compliance schedule.






     Whether the work is conducted before the order is issued or after, detail




in the order regarding completed and proposed work will help avoid future




questions of compliance with the order.  The greater the specificity in the




order, the easier it will be for the Agency or a court to determine whether




the terms of the agreement have been met.






     Enforcement officials should not underestimate the level of detail that




can be incorporated into orders.  Well design specifications, decontamination




procedures, and sampling frequencies are all suitable for specification.  In




addition, enforcement officials should consider specifying certain behaviors




or actions on the part of the respondent.  For example, officials may wish




to require that a qualified geologist be present to take field notes (e.g.




drilling logs and boring logs) during all well installations and soil boring




programs.






     No requirement is inappropriate if it is directly related to the ability




of the owner/operator to meet his regulatory obligations.  Table 6.1 summarizes




some  of the items enforcement officials may wish to consider when developing




orders.






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        Table 6.1  Possible Elements of a Technically-Specific Order




HYDROGEOLOGIC ASSESSMENT

   Boring Program

   o  Spacing of boreholes
   o  Depth and location of boreholes
   o  Vertical spacing of samples within each borehole
   o  Sampling equipment to be used for boring program
   o  Information to be logged for each borehole
   o  Requirement that hydrogeolegist or geotechnical engineer be present to
      log boreholes
   o  Method for stabilizing selected boreholes until wells  are installed
   o  Method of data presentation
   o  Requirement to use Unified Soil Classification System  (USCS),
      Atterberg limits


   Water Level Monitoring Program

   o  Spacing/number of piezometers or wells
   o  Method for water level measurements
   o  Required precision of measurement (to  the nearest  0.1  foot  or  to  the
      nearest centimeter)
   o  Requirement that measuring points be surveyed  from established benchmarks
   o  Number of hydrogeologic cross sections  and  appropriate scale
   o  Water level contour maps
   o  Identification of local sources of ground-water withdrawal  and recharge
      and approximate schedule of use


   Hydraulic Conductivities

   o  Method of determining hydraulic conductivities,  porosity


   Additional Information Requirements

   o  Description of regional geologic and hydrogeologic characteristics
   o  Analysis of geomorphic or topographic  features that might influence
      ground-water flow system
   o  Zones of higher or lower permeability  that  might direct or  restrict
      flow of contaminents
   o  Zones of significant fracturing or channeling  in consolidated  deposits
   o  Sand or gravel deposits in unconsolidated deposits
   o  Description of manmade hydraulic structures (pipelines,  french drains,
      ditches, etc.)
   o  Soil properties including cation exchange capacity, organic content
      temperature profile, grain size distribution

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   Additional Information (continued)

   o  Identification of zones of recharge and discharge
   o  Interpretation of hydraulic interconnections between saturated zones
NETWORK DESIGN

   Placement of Wells
   o  Maximum horizontal spacings
   o  Requirement for well clusters
   o  Depth requirements (most in surficial aquifer,  one or more in deeper
      aquifer
   o  Exact well locations
   o  Minimum number of background wells


   Well Design and Construction

   o  Casing material and diameter; prohibition against joining section with glues
      or sealants
   o  Screen slot size and maximum length
   o  Drilling techniques; prohibition on use of drilling muds
   o  Drill decontamination procedures
   o  Well development techniques; prohibition on use of water other than formation
      water or "certified" pure water
   o  Filter pack material and method of filter-pack  emplacement
   o  Method and material for sealing annular space
   o  Requirement for locked well caps
   o  Requirement that wells be designed to last at least 30 years
   o  Requirement that wells yielding turbid samples  be redeveloped or replaced
   o  Information to be documented during construction of each well


SAMPLING AND ANALYSIS

   Analytes of Interest

   o  List of parameters to be monitored for
   o  Requirement to collect data on major ions and anions, e.g.,  Cl~", Fe,  Mn,
      Na , Ca+,  Mg+, N03~, P0^=,  silicate, ammonium,  alkalinity, acidity.
   o  Requirement for field monitoring of pH,  conductivity, and temperature for
      each sample


   Sample Collection

   o  Evacuation procedures;  handling procedures for  evacuation water
   o  Method for sampling "floaters" and "sinkers"


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   Sample Collection (continued)

   o  Acceptable materials for inclusion in sampling devices and/or specific
      device to be used
   o  Performance standard for sample collection - "sampling device and
      methodology must be selected to yield representative samples in
      light of the parameters that are being monitored"
   o  Requirement that sampling devices be dedicated to each well or procedures
      for decontaminating equipment between wells
   o  Precautions on use of specific sampling devices (e.g., bladder pumps must
      be operated in a continuous manner so that they do not produce pulsating
      samples that are aerated in the return tube upon discharge; check valves
      must be designed and inspected to ensure that fouling problems do not
      reduce delivery capabilities or result in aeration of sample, etc.)
   o  Specification of acceptable cords/cables to be used to lower bailers;
      prohibitions on use of braided cables, polyethylene or nylon cords
   o  Maximum sampling rates, generally not to exceed 100 milliliters/minute
SAMPLING PRESERVATION AND HANDLING

  o  Designation of appropriate sample containers - polyethylene containers
     with polypropylene caps when metals are analytes of interest;  glass
     containers when organics are analytes of interest
  o  Requirement to use preservation methods designated in SW-846
  o  Preferred handling procedures e.g., volatile organics:  no filtering
     or headspace in containers allowed; metals:  two aliquots from each
     sample - one filtered and analyzed for dissolved metals, and one
     not-filtered and analyzed for total recoverable metals
ANALYSIS

   o  Requirement for use of field blanks,  standards,  and spiked samples
      for QA/QC
   o  Requirement to use analytical methods described  in SW-846
   o  Requirement to perform field analysis of pH,  conductivity, and
      temperature
CHAIN OF CUSTODY

   o  Minimum requirements for chain-of-custody program (e.g.,  sample labels,
      seals field log book, chain of custody record,  sample analysis request
      sheet, laboratory log book)
DATA REVIEW AND PRESENTATION

   o  Standard protocol for reporting of less than detection limit concentrations
   o  Requirement that data values for each pollutant be reported using the same
      number of significant digits,  in general at least three                    t

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DATA REVIEW AND PRESENTATION (continued)
   o  Requirement that units of measure for a given chemical parameter be
      consistent throughout report and accompany each chemical named

   o  Requirement that raw data be submitted in a table that lists for each
      concentration value: the pollutant, the well code, and the unit of
      measure

   o  Requirement that owner/operator compile the following ten statistics for
      each of four summary tables organized by pollutant; by pollutant-well;  by
      pollutant-date; and by pollutant-well-date:

                0  Number of lower than detection limit values
                0  Total number of values
                0  Mean
                0  Median
                0  Variance
                0  Standard Variation
                0  Coefficient of variation
                0  Range
                0  Minimum value
                0  Maximum value
ADDITIONAL PLUME CHARACTERIZATION ACTIVITIES

o  Requirement to use certain remote sensing (e.g., aerial photography)
   and geophysical techniques (e.g., electrical resistivity, ground-pene-
   trating radar, borehole geophysics)
o  Requirement to determine the physical and chemical characteristics of the
   facility's leachate including density, solubility, vapor pressure,
   viscosity, and octanol-water partition coefficient
PERMIT APPLICATION REQUIREMENTS

o  Requirement to collect background data on all Appendix VIII constituents
   detected in ground water
o  Requirement to submit applicable data, studies, and plans detailed in
   §270.14(c)(l) - (8)
OTHER PROVISIONS

o  Schedule for implementation including stipulated penalties for missed milestones
o  Penalties for past and present violations
o  Procedures for plan submittal, modification, and/or approval
o  Provision that incorporates all plans, reports, and schedules required by the
   ORDER into the ORDER itself such that any non-compliance with a plan, report
   or schedule consitutes non-compliance with the order


                                 6-11

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OTHER PROVISIONS (continued)

o  Clause that reserves government's  right to take  further action as necessary,
   including additional ground-water  monitoring and/or cleanup,  to bring respondent
   into compliance with RCRA other applicable State or Federal law
o  Requirement to develop and implement  a community relations  plan
o  Requirement to develop and implement  a health and safety plan for workers
   involved with monitoring or corrective action
o  Requirement to designate corporate contact person,  supply corporate
   organizational charts, and provide background information and qualifications
   of any contractors used to meet the terms  of the ORDER
o  Clause guaranteeing site access for employees, agents  or contractors
   of complainant to inspect and evaluate compliance with ORDER pursuant to
   authority in §3007 of RCRA 42 USC  §6927
o  Requirement to develop Quality Assurance Project Plan  in accordance with
   EPA guidance document QAMS - 005/80.
o  EPA idemnification clause
o  Clause guaranteeing EPA's right to take or split samples
o  Clause establishing EPA's ability  to  halt  work if necessary
o  Effective date
o  Signature
                                                                                   €
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6.4  §3008(a) Orders






     The §3008(a) process can accomodate the issuance of either phased or




technically-specific orders.  In fact, a single order may incorporate both




approaches.






     The process of issuing a §3008(a) order is diagrammed in Appendix B.




Briefly, the process involves the issuance of a complaint and compliance order




followed by negotiations (if desired by both parties), a hearing (if requested




by the respondent) and the issuance of a consent order or a final unilateral




order.  If a respondent does not answer the complaint, (s)he become subject




to a default order.  Generally, a respondent answers the complaint, requests




a hearing, and then either enters into a consent agreement with the Agency or




proceeds through the hearing and becomes subject to a final order issued




unilaterally.






     If the Agency feels confident that a particular respondent will not




default, the compliance order issued with the complaint may include a




broadly-stated remedy such as "compliance with Part 265 Subpart F and Part




270."  Since the respondent is required to undertake remedial activities




and/or pay any assessed penalty only after the consent order or final order




is issued, it is only in the consent or final order that specificity becomes




critical.   Some Regions seem to prefer compliance orders with broadly-stated




remedies,  although developing a phased compliance order, which would require




the respondent to develop detailed plans, should prove to be fairly simple




in most cases.
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     The Regions should try to avoid the situation where a broadly-stated




compliance order is issued with the complaint, the respondent fails to answer,




and a default order is issued.  In this case the terras of the compliance




order may become the terms of the default order.  Although respondents do




not usually fail to answer complaints, especially when sizeable penalties




are involved, the Region should consider the possibility of a respondent




failing to answer,  before deciding on a format for the compliance order.






     The following  describes in more detail the options available under




§3008(a):






      OPTION (1):  The Region may issue a complaint with a phased compliance




order, enter negotiations with the respondent and then follow one of several




courses of action,  depending on whether a settlement is reached with the




respondent.  If both parties are willing to settle and can reach agreement




on the remedy, a consent order may be negotiated in either a phased or a




technically-specific format, depending on how detailed the discussions have




been in negotiating sessions.  If in the course of negotiations the facility




has filled in any gaps in the hydrogeologic study and the Region and respon-




dent have agreed on such details as the list of indicator parameters and the




location of wells,  a consent order could be negotiated that specifies the




location of wells,  construction specifications, etc.  The order might also




specify sampling and analytical procedures and schedules, or it might require




the respondent to develop and submit a plan for sampling and analysis.  As




noted in section 5.2, the Region might choose to enter into a consent agreement




only after completion of the remedial activities by the respondent.  In such
                                 6-14

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cases, the consent order should document, in detail, the work that has




been completed by the respondent.







     If the parties are unable to reach settlement and a hearing takes place,




the Region will have the opportunity to submit a proposed final order to the




Presiding Officer.  The proposed final order may be phased or may be tech-




nically specific, depending on the amount of information available to the




Region.  In any case, the proposed order should not simply include a broad




mandate, like "the owner/operator must come into compliance with Part 265




Subpart F and Part 270."  It should either specify a detailed remedy itself




or should require the owner/operator to develop a plan that specifies details.




Unless it is clear to both parties what the order requires, it will be diffi-




cult to determine whether the facility in fact achieves compliance.  If




there is room for dispute as to what the order requires, it may be difficult




for the Agency to enforce the terms of the order, should that later become




necessary.







     OPTION (2):  The Region may issue a complaint with a proposed compliance




order that simply requires "compliance with Part 265 Subpart F and Part 270"




rather than a phased compliance order. The steps following complaint issuance




would be the same as those described in Option 1.  Although it is acceptable




to put a broad remedy in the initial compliance order, the consent order or




proposed final order must contain specificity (or require the respondent to




propose the specifics).   When the order goes into effect it must express




what "compliance" entails.  As described earlier, the Region should not use a




vaguely-worded compliance order if there is a chance that the respondent will




not answer the complaint.







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6.5  §3013 Orders


     Section 3013 orders can be Issued in either a one- or two-step process.

Both processes are adaptable to the Issuance of either phased or specific

orders.  The one-step process involves one of the following:
        o issuance of a phased order requiring the sequential development,
          submittal, and execution of plans;  or

        o issuance of a technically-specific order, after the details are
          worked out in negotiations with the respondent.
The two-step process involves the issuance of a preliminary order requiring

the development and subraittal of plans for approval,  followed by the issuance

of an order requiring the execution of the plans as modified by the Agency.

The second order could be phased or specific, depending on the amount of

information available.  For example, if the remedy sought by the Agency

included a significant amount of hydrogeologic investigation as well as

construction and sampling of wells, the preliminary order might require the

development of a plan for the hydrogeologic study and a schedule for the

development and implementation of plans for later stages of the remedy.

The second order would then require the owner/operator to conduct the hydro-

geologic work and then sequentially develop, submit,  and carry out plans for

well construction and sampling.


     Alternatively, the preliminary order could require the development of

well construction and sampling plans, which would entail conducting a hydro-

geologic investigation.  The second order then would be able to specify

detail as to the locations and specifications of the wells and plans for

sampling and analysis.


                                 6-16
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6.6  §3008(h) Orders






     Section 3008(h) orders can accomodate both phased and specific orders  in




a manner similar to that described in section 6.4 for §3008(a)  orders.
                                6-17

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                 APPENDIX A:




MODEL PHASED ORDER FOR GROUND-WATER MONITORING

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                             EXAMPLE PHASED ORDER
     Pursuant to Section(s)  	 of  the Resource Conservation  and  Recovery  Act
(RCRA),  42 U.S.C. 69	 it is ordered  that 	 shall comply with the
following requirements:
  1.  Within	calendar days of the effective  date of  this  ORDER,  respondent
      shall develop and submit for EPA approval a plan  for conducting  a  hydro-
      geologic investigation of the site.   The  plan should be  designed to
      provide the following information:
      a.  A description of the regional geologic and hydrogeologic characteristics
          in the vicinity, including:

             1)  regional stratigraphy:  description of  strata including
                 strike and dip,  identification of  stratigraphic  contacts,
                 petrographic analysis

             2)  structural geology:  description of local  and regional
                 structural features  (e.g.,  folding,  faulting,  tilting,
                 jointing, etc)

             3)  depositional history

             4)  regional ground-water flow  patterns

             5)  identification  and characterisation  of  areas of  recharge
                 and discharge

      b.  An analysis of any topographic features that might  influence  the
          ground-water flow system (Note that  stereoscopic analysis  of  aerial
          photographs should aid  in this analysis).
      c.   A classification and description  of  the  hydrogeologic properties  of
          all the hydrogeologic units  found at the site  (i.e. , the  aquifers  and
          any intervening saturated  and unsaturated units),  including:

             1)   hydraulic conductivity,  effective porosity

             2)   lithology,  grain size, sorting, degree  of cementation

             3)   an interpretation of  hydraulic interconnections  between
                 saturated zones
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    d.  Using a topographic map or aerial photograph as a base, submit maps
        of structural geology and at least four hydrogeologic cross sections
        showing the extent (depth, thickness, lateral extent) of all hydro-
        geologic units within the facility property, identifying:


           1)  sand and gravel deposits in unconsolidated deposits

           2)  zones of fracturing or channeling in consolidated
               deposits

           3)  zones of higher permeability or lower permeability that might
               direct or restrict the flow of contaminants

           4)  perched aquifers

           5)  the uppermost aquifer (includes all water-bearing zones
               above the first confining layer that may serve as a pathway
               for contaminant migration Including perched zones of satur-
               ation)

    e.  A description of water level or fluid pressure monitoring including:

           1)  water-level contour and/or potentiometric maps

           2)  hydrologic cross sections showing vertical gradients

           3)  an interpretation of the flow system, including the
               vertical and horizontal components of flow

           4)  an interpretation of any change in hydraulic gradients
               due, for instance, to tidal or seasonal influences

    f.  A desciption of manmade influences that may affect the hydrogeology of
        the site,  identifying:

           1)  local water-supply and production wells with an approximate
               schedule of pumping

           2)  manmade hydraulic structures (pipelines, french drains, ditches)

    The plan should include a description of the field methods and other infor-
mation sources proposed for the study and a summary of which data will be col-
lected by each method.  The proposed methods should include, but are not
limited to:
        A program of soil borings,  as required to adequately describe
        the subsurface geology of the site. The program should provide
        for the presence of a qualified geologist or geotechnical
                                  A-2

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        engineer to log and describe the materials encountered during
        the boring.  The program should also describe the methods pro-
        posed to stabilize selected holes until monitoring wells are
        installed.

    b.   A sufficient number of piezometers to characterize ground-water
        depth and gradient (both horizontal and vertical) over the
        entire area of the site.

    c.   The use of slug and/or pump tests as appropriate to determine
        hydraulic conductivities

        NOTE: Geophysical techniques,  both borehole and surficlal, are effec
              tive supplementary investigative techniques that should be
              considered
    The plan shall contain a schedule for conducting the proposed hydrogeologic
    assessment and shall be submitted to:

                 Deputy Director,  Air and Waste Management Division
                 Environmental Protection Agency
                 444 RCRA Way
                 Any town, USA 00001


2.  Within _ calendar days of the  effective date of this ORDER, respondent shall
    develop and submit to EPA a list of proposed indicator parameters capable of
    detecting leakage of hazardous waste or hazardous constituents into ground
    water.  The parameters should  be representative of constituents at least as
    mobile as the most mobile constituents that could reasonably be derived from
    the facility's waste, and should be chosen after considering:

    a.   the types, quantities, and concentrations of constituents in wastes
        managed at the facility;

    b.   the mobility, stability, and persistence of waste constituents or their
        reaction products in the unsaturated zone beneath the waste management
        area;

    c.   the detectability of the indicator parameters,  waste constituents or
        reaction products in ground  water;

    d.   the concentration or value and the natural variation (known or suspected)
        of the proposed monitoring parameter in background ground water.


    The list should include the basis for selecting each proposed indicator
    parameter, including any analyses or calculations performed.  The basis
    for selection must include chemical analysis of the facility's waste  and/or
    leachate as appropriate.


                                  A- 3

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      The list should also include parameters to characterize the site-specific
      chemistry of ground water at the site, including but not limited to the
      major anions and cations that make up the bulk of dissolved solids in
      water (i.e., Cl~, Fe, Mn, Na+, S04, Ca+,  Mg+,  K*" N0~ ,  P04=, silicate,
      ammonium).

3.  Within 	 calendar days of written approval by EPA, the respondent shall
    promptly implement the hydrogeologic investigation plan according to the
    terms and schedules contained therein.

4.  Within 	 calendar days after completion of the  hydrogeologic investigation,
    the respondent will submit to EPA a full report  that provides the information
    described in  paragraph 1.

5.  Also within 	 days after  the completion of the  hydrogeologic investigation,
    the respondent will submit to EPA a plan for the design and installation  of
    a monitoring  well network  that will meet the following requirements:

    a.  The upgradient wells must be capable of yielding samples that are
        representative of background water  quality in the uppermost aquifer
        and are not affected by the facility.  The number and location of the
        wells must be sufficient to: 1) characterize the spatial variability
        of background water; and 2) meet the needs of the statistical test
        proposed  pursuant to paragraph 	.

    b.  The downgradient wells must be capable  of immediately detecting any
        statistically significant amounts of hazardous waste  or hazardous
        constituents that migrate from the  facilty into the uppermost aquifer.

    c.  The monitoring system  should be designed to  operate for a period of no
        less than thirty years.


    The plan should include the following elements:

      a.  A description and map of proposed well locations, including a survey
          of each well's surface reference  point and the elevation of its top
          of casing.

      b.  Size and depth of wells;

      c.  Desciption of well-intake design,  including screen  slot size and length;
          filter  pack materials and method  of filter-pack emplacement.

      d.  Type of proposed well casing and  screen materials.   The choice of well
          materials should be  made in light of  the parameters to be monitored for
          and the nature of the leachate that could  potentially migrate from  the
          facility.  The well  materials should: 1) minimize the potential of
          adsorption and desorption of constituents  from the  samples; and
          2) maintain their integrity for the expected life of the system
          (at least thirty years).


                                    A-4
€

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    e.  Methods used to seal the well from the surface and prevent downward
        migration of contaminants through the well annulus.

    f.  Description of the methods or procedures used to develop the wells.


6.  Also within 	 days after the completion of the hydrogeologic assessment,
    the Respondent shall sumbit a sampling and analysis plan capable of
    yielding representative samples for a comparison of up- and downgradient
    wells.  The plan should include the following elements:

    a.  Well evacuation procedures including volume to be evacuated prior to
        sampling and handling procedures for purged well water

    b.  Sample withdrawal techniques.  Sampling equipment and materials (tubing,
        rope, pumps, etc.) shall be selected to yield representative samples in
        light of parameters to be monitored for.  The sampling protocol will
        include field measurement of pH, conductivity, and temperature for
        each sample.

    c.  Sample handling and preservation techniques including provision for
        field-filtration of samples as appropriate.

    d.  Procedures for decontaminating sampling equipment between sampling
        events.

    e.  Procedures for measuring ground-water elevations at each sampling
        event

    f.  Chain of custody procedures to be used for all phases of sample
        management.

    g.  Laboratory analytical techniques, including EPA-approved analytical
        methods and quality assurance, detection levels, quality control
        procedures.

    h.  Procedures for performing a comparison of upgradient and downgradient
        ground water to determine whether contamination has occurred.   The pro-
        cedures should include:

           1)  A proposed method (statistical or otherwise) to compare up-
               gradient and downdradient well water that provides a reasonable
               balance between the probability of falsely identifying  and
               failing to identify contamination.

           2)  An accelerated sampling schedule to establish data for  the
               comparison.  In no instance shall sampling exceed 	 months.

           3)  A proposed method for data organization and presentation.
                                  A-5

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  7.  By no later than 	 days after EPA approval of the monitoring well network
      plan, Respondent shall complete the installation of the monitoring well
      network.
  8.  By no later than 	 days after the installation of  the monitoring well
      network, Respondent shall implement the sample and  analysis  plan, perform
      the comparison and submit the results to EPA for review.


  9.  If there is a statistically significant difference  between upgradient  and
      downgradient well water,  the Respondent will develop  a ground-water asses-
      sment plan capable of determining the following:


      a.  The extent of migration of hazardous constituents into ground water.

      b.  The concentration of  each Appendix VIII  constituent throughout the
          plume or the maximum concentration of each Appendix VIII in the
          plume.

      c.  Background concentrations for all Appendix VIII constituents detected
          in ground water.

      d.  Waste/leachate characteristics including specific gravity,  viscosity,
          solubility in water,  and octanol-water partition  coefficient.

      e.  Soil properties including cation exchange capacity, organic content,
          and temperature.


      The plan should describe the methods proposed to accomplish  the above
      objectives including  indirect and direct techniques.   The sampling and
      analysis plan developed pursuant  to paragraph 6 should be revised to meet
      the new objectives of this  monitoring phase.   The plan should include  an
      expeditious schedule  for the implementation  of the  above assessment, and
      should be submitted to EPA  no later than 15  days after the confirmation of
      leakage.

10.   Within 	 calendar days of  EPA approval of the assessment plan,  the Respondent
      will begin to execute the plan according to  the terms and schedules contained
      therein.  Within   days  of the completion of the assessment, the Respondent
      will submit the results to  the Agency,  including all  raw data collected,  all
      calculations performed, and an interpretation of the  findings.


11.   Based on the results  of the ground-water assessment,  the Respondent will
      fulfill his/her obligations pursuant to §270.14(c)(7) or (8) by developing
      a compliance monitoring and/or corrective action program as  appropriate.
      Respondent will submit whatever plans and engineering studies are necessary
      to describe the proposed program to EPA no later than 	 months after the
      completion of the ground-water assessment described in paragraph nine.      ^


                                    A-6

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      All plans,  reports,  and schedules required by  the terras  of  this ORDER are,
      upon approval by EPA, incorporated into this ORDER.   Any noncorapliance with
      such approved studies,  reports,  or schedules shall be termed  noncompliance
      with this ORDER.

13.   In the event of Agency  disapproval (in whole or in part) of any plan required
      by this ORDER, EPA shall specify any deficiencies in writing.   The Respondent
      shall modify the plan to correct the deficiencies within 	 days from receipt
      of disapproval by EPA.   The modified plan shall be submitted  to EPA in
      writing for review.

      Should the Respondent take exception to all or part  of EPA's  disapproval, the
      Respondent shall submit to EPA a written statement of the grounds  Cor the
      exception.   Representatives of EPA and the Respondent may confer in person
      or by telephone in an attempt  to resolve any disagreement.  If  agreement
      is reached, the resolution shall be written and signed by representatives
      of each party.  In the  event that resolution is not  reached within 15 days,
      the Respondent shall modify the plan as required by  EPA.

14.  In the event that the respondent  fails to:

     a.  Comply with the milestones  contained in paragraphs 3, 7, 8,  or  10;

     b.  Provide the plans and information described in paragraphs  1,  2,  4,  5,
         6, 8, 9, 10, or 11;

     (s)he shall pay stipulated penalties from the date of the violation as
     follows:

     a.  $5000.00 per day  for failure to comply with a milestone  listed  above;

     b.  $1000.00 per day  for failure  to provide a plan or information listed
         above.
15.   Notwithstanding compliance with  the  terms  of  this ORDER, Respondent may
     be required to  take  further  actions  as  necessary, including additional
     ground-water monitoring,  assessment, and/or corrective  action, to  come into
     compliance  with RCRA,  or  other applicable  state or Federal laws.
                                   A-7

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                APPENDIX B:




DIAGRAM OF PART 22 ADMINISTRATIVE PROCEEDINGS

-------
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                                             B-l

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      Ground-Water Monitoring
Technical Enforcement Guidance Document
                                   Draft
August, 1985

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                             TABLE OF CONTENTS

                                                                     Page

CHAPTER ONE.  CHARACTERIZATION OF SITE HYDROGEOLOGY                  1-1

1.1  investigatory Tasks for Hydrogeologic Assessments 	  1-2

1.2  Characterization of Subsurface Geology 	  1-5
     1.2.1  Site Characterization Boring Program 	  1-6
     1.2.2  Interpretation of Subsurface Geology 	  1-16
     1.2.3  Presentation of Geologic Data 	  1-17

1.3  Identification of Ground-Water Flowpaths 	  1-20
     1.3.1  Determining Ground-Water Flow Directions 	  1-20
     1.3.1.1  Ground Water Level Measurements 	  1-22
     1.3.1.2  Interpretation of Ground-Water Level Measurements ...  1-23
     1.3.1.3  Establishing Vertical Components of Ground-Water
              Flow 	  1-25
     1.3.1.4  Interpretation of Flow Direction	  1-27
     1.3.2  Seasonal and Temporal Factors:  Ground-Water Flow 	  1-29
     1.3.3  Determining Hydraulic Conductivities 	  1-30

1.4  Identification of the Uppermost Aquifer 	  1-33


CHAPTER TWO.  PLACEMENT OF DETECTION MONITORING WELLS 	  2-1

2.1  Placement of Downgradient Detection Monitoring Wells 	   2-3
     2.1.1  Location of Wells Relative to Waste Management Areas ..  2-3
     2.1.2  Horizontal Spacing Between Downgradient Monitoring
            Wells 	  2-5
2.2  Depth of Wells/Vertical Sampling interval(s) 	  2-15
     2.2.1  Depth of Wells 	  2-15
     2.2.2  Thickness of the Vertical Sampling Interval(s) 	  2-15

2.3  Placement of Upgradient (Background) Monitoring Wells 	  2-24


CHAPTER THREE.  MONITORING WELL DESIGN AND CONSTRUCTION 	  3-1

3.1  Drilling Methods 	  3-1
     3.1.1  Hollow-stem Continuous-Flight Auger 	  3-3
     3.1.2  Solid-Stem Continuous-Flight Auger 	  3-3
     3.1.3  Cable Tool 	  3-4
     3.1.4  Air Rotary 	  3-4
     3.1.5  Water Rotary 	  3-5
     3.1.6  Mud Rotary 	  3-6

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                             TABLE  OF CONTENTS
                                (Continued)
3.2  Monitoring Well Construction Materials 	  3-6
     3.2.1  Well Casings and Well Screen 	  3-1
     3.2.2  Monitoring Well Filter Pack and Annular Sealant 	  3-11

3.3  Well Intake Design 	  3-12

3.4  Well Development 	  3-13

3.5  Documentation of Well Design and Construction 	  3-15

3.6  Specialized Well Designs 	  3-15

3.7  Evaluation of Existing Wells 	  3-18


CHAPTER FOUR.   SAMPLING AND ANALYSIS 	  4-1

4.1  Elements of Sampling and Analysis Plans 	  4-2

4.2  Sample Collection 	  4-3
     4.2.1  Measurement of Static Water Level Elevation 	  4-3
     4.2.2  Detection of Immiscible Layers 	  4-3
     4.2.3  Well Evacuation 	  4-5
     4.2.4  Sample Withdrawal 	  4-7
     4.2.5  In-Situ or Field Analyses 	  4-9

4.3  Sample Preservation and Handling 	  4-10
     4.3.1  Sample Containers 	  4-11
     4.3.2  Sample Preservation 	  4-13
     4.3.3  Special Handling Considerations 	  4-13

4.4  Chain of Custody 	  4-18
     4.4.1  Sample Labels 	  4-18
     4.4.2  Sample Seal 	  4-19
     4.4.3  Field Logbook 	  4-19
     4.4.4  Chain-of-Custody Record 	  4-19
     4.4.5  Sample Analysis Request Sheet 	  4-20
     4.4.6  Laboratory Logbook 	  4-20

4.5  Analytical Procedures 	  4-20
4

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                                        TABLE  OF CONTENTS
                                           (Continued)
                                                                                Page
           4.6  Field and Laboratory Quality Assurance/Quality Control 	  4-21
                4.6.1  Field QA/QC Program 	  4-21
                4.6.2  Laboratory QA/QC Program 	  4-22

           4.7  Evaluation of the Quality of Ground-Water Data 	  4-22
                4.7.1  Reporting of Low and Zero Concentration Values 	  4-23
                4.7.2  Significant Digits 	  4-28
                4.7.3  Missing Data Values 	  4-30
                4.7.4  Outliers 	  4-31
                4.7.5  Units of Measure 	  4-32
           CHAPTER FIVE.  STATISTICAL ANALYSIS OF DETECTION MONITORING DATA ..  5-1

           5.1  Methods for Presenting Detection Monitoring Data 	  5-1

           5.2  Introductory Topics:  Available t-Tests, Definition of Terms,
                 and Components of Variability 	  5-1

           5.3  Statistical Analysis of the First Year's Data 	  5-4

           5.4  Statistical Analysis of Detection Monitoring Data After the
                First Year 	  5-5
                5.4.1  Comparison of Background Data Collected the First Year
                       With Upgradient Data Collected in Subsequent Years ....  5-5
                5.4.2  Comparison of Background Data Collected During the
                       First Year With Downgradient Data Collected in
                       Subsequent Years 	  5-7


           CHAPTER SIX.  ASSESSMENT MONITORING 	  6-1

           6.1  Description of Hydrogeologic Conditions 	  6-3

           6.2  Description of Detection Monitoring System 	  6-4

           6.3  Description of Approach for Making First Determination -
                False Positives 	    6-5

           6.4  Description of Approach for Conducting Assessment 	    6-7
                6.4.1  Use of Direct Methods	    6-8
                6.4.2  Use of Indirect Methods 	    6-8
                6.4.3  Mathematical Modeling of Contaminant Movement 	    6-10
t

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                            TABLE OF CONTENTS
                                (Continued)
6.5  Description of Sampling Number,  Location,  and Depth 	    6-12
     6.5.1  Collection of Additional  Site Information 	    6-13
     6.5.2  Sampling Density 	    6-14
     6.5.3  Sampling Depths 	    6-l"7

6.6  Description of Monitoring Well Design and  Construction 	    6-18

6.7  Description of Sampling and Analysis Procedures 	    6-20

6.8  Procedures for Evaluating Assessment Monitoring Data 	    6-22
     6.8.1  Listing of the Data 	    6-23
     6.8.2  Summary Statistics Tables 	    6-26
     6.8.3  Data Simplification 	    6-31
     6.8.4  Graphic Displays of Data 	    6-33
     6.8.4.1  Plotting Data Over Time 	    6-33
     6.8.4.2  Plotting Data on Maps 	    6-33

6.9  Rate of Migration 	    6-36

6.10  Reviewing Schedule of Implementation 	    6-41


GLOSSARY


APPENDICES

A.  Evaluation Worksheets

B.  Methodology and Example Applications That Describe the Use of
    Cochran's Approximation to the Behrens-Fisher and the Averaged
    Replicate t~Tests

C.  Description of Selected Geophysical Methods and Organic Vapor Analysis
f

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                              LIST OF TABLES
1-1.   Hydrogeologic Investigatory Techniques 	  1-3
1-2.   Factors Influencing Boring Well spacing 	  1-7
1-3.   Suggested Laboratory Methods for Core Samples 	  1-11
2-1.   Factors Used to Adjust Horizontal Spacing of Monitoring
      Wells 	  2-6
2-2.   Factors Affecting Number of Wells Per Location (Clusters) ...  2-17
3-1.   Drilling Methods for Various Types of Geologic settings 	  3-2
4-1.   Sampling and Preservation Procedures for Detection
      Monitoring 	  4-14
4-2.   A Listing and Description of Codes Used to Indicate That
      Pollutant Concentrations Were Below a Concentration Which
      Can Be Measured Accurately or That The Pollutants Were Not
      Present 	  4-25
4-3.   An Example of a Data Submission Which May Be Concealing an
      Increasing Concentration Trend or Where the Units of Measure
      Were Reported Incorrectly 	  4-27
4-4.   Examples of Data Values and Their Associated Number of
      Significant Digits 	  4-29
6-1.   An Example of How Assessment Monitoring Data Should be
      Listed 	  6-25
6-2.   An Example of How Data Should be Summarized by GWCC 	  6-28
6-3.   An Example of How Data Should be Summarized by GWCC/Well
      Combination 	  6-29
6-4.   An Example of How Data Should Be Summarized by GWCC/Well/
      Date Combination 	   6-30
6-5.   An Example of How Ranks of the Mean Concentrations for Each
      GWCC/Well Combination Can Be Used to Simplify and Present
      Concentration Data collected for a Variety of GWCCs in a
      Number of Monitoring Wells 	  6-32

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                              LIST  OF FIGURES

                                                                     Page

1     Overview of the Enforcement Process 	     6
1-1.  Field Boring Log Information 	  1-10
1-2.  Progressive Boring Approach:   Scenario 1 	  1-14
1-3.  Progressive Boring Approach:   Scenario 2 	  1-15
1-4.  Geologic Cross Section Survey Plan 	  1-18
1-5.  Example of an Acceptable Geologic Cross Section 	  1-19
1-6.  Example of a Site Map 	  1-21
1-7.  Potentiometric Surface Map 	  1-24
1-8.  Example of Improper Well Placement Based Upon Flow
      Components 	  1-25
1-9.  Cross Sectional View Illustrating Flow Nets 	  1-28
1-10. Example of Hydraulic Interconnection Between Water-Bearing
      Units 	  1-35
1-11. An Example of Hydraulic interconnection Caused by
      Fracturing 	  1-37
1-12. Perched Water Zones as Part of the Uppermost Aquifer 	  1-38
1-13. An Example of an Undetected,  Structurally Complex
      Uppermost Aquifer 	  1-39
1-14. An Example of an Undetected Portion of the Uppermost
      Aquifer (Permeable Sandstone Unit Near a Coastal Area) 	  1-41
1-15. Example of a Contaminant That May Affect the Quality
      of a Confining Layer 	  1-42
2-1.  Dowgradient Wells Immediately Adjacent to Hazardous Waste
      Management Units 	  2-4
2-2.  Well Spacing Based Upon Waste Character 	  2-8
2-3.  Wei 1 spacing Based on Site Geology 	  2-9
2-4.  Well Placement Based Upon Locally Inundated Areas 	  2-11
2-5.  Well Placement Based Upon a Change of Preferential Routes
      of Migration 	  2-12
2-6.  Well Placement Based Upon Structural Fracturing 	  2-13
2-7.  Well Placement Based Upon Age and Waste Character 	  2-14
2-8.  Example of Wider Monitoring Well Spacing Due to the Use
      of Supplementary Investigative Techniques 	  2-19
2-9.  Well Depth Determination Based Upon Flow-Net Analysis 	  2-21
2-10. Well Placement Based Upon Flow-Net Analysis 	  2-22
2-11. Well Placement Based Upon Changes in Geology 	  2-23
2-12. Well Placement Based Upon Complex Geology 	  2-25
2-13. Well Depth Based Upon Possible Hydraulic Connection 	  2-26
2-14. Placement of Background Wells 	  2-29
3-1.  General Monitoring Well - Cross Section 	  3-8
3-2.  Composite Well Construction (Inert Construction Materials
      in Saturated Zone)	  3-10

                                (Continued)
4

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                              LIST OF FIGURES
                                (Continued)
3-3.   Decision for Turbid Ground-Water Samples 	  3-14
3-4.   Monitoring Well Cross Section—Dedicated Positive Gas
      Placement Bladder Pump 	  3-17
3-5.   Monitoring Well Cross Section—Dedicated Positive Gas
      Displacement Bladder Pump and Subcasing for Discrete
      Sampling of Light Phase immiscible Layers 	  3-19
3-6.   Monitoring Well Cross section—Dedicated Positive Gas
      Displacement Bladder Pump and Subcasing for Discrete
      Sampling of Dense Phase Immiscible Layers 	  3-20
6-1.   Procedure for Evaluating False Positive Claims by
      Owner/Operators 	  6-6
6-2.   initial Placement of Well Clusters to Define the Extent
      of Contamination in the Horizontal Plane 	  6-16
6-3.   Vertical Well Cluster Placement 	  6-19
6-4.   Selection of Plume Characterization Parameters for Units
      Subject to Part 265 and Part 270 	  6-21
6-5.   Plot of Chromium Concentrations Over Time (Well 9A) 	  6-34
6-6.   Chromium and Lead Concentrations Over Time (Well 9A) 	  6-35
6-7.   General Schematic of Multiphase Contamination in a sand
      Aquifer 	  6-38

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                               CHAPTER ONE
                  CHARACTERIZATION OF SITE  HYDROGEOLOGY

     The adequacy of an owner/operator's ground-water monitoring program
hinges, in large part, on the quality and quantity of the hydrogeologic
data the owner/operator used in designing the program.  Enforcement
officials, therefore, should evaluate the adequacy of an owner/operator's
hydrogeologic assessment as a first step towards ascertaining the overall
adequacy of the detection and/or assessment monitoring network.  Clearly,
if the design of the well system is based upon poor data, the system
cannot fulfill its intended purpose.
     In performing this evaluation, enforcement officials should ask
themselves two questions.
     •  Has the owner/operator collected enough information to:  (1) have
        an understanding sufficient to identify potential contaminant
        pathways and  (2) support the placement of wells capable of
        determining the facility's impact on the uppermost aquifer?
     •  Did the owner/operator use appropriate techniques to collect and
        interpret the information used to support well placements?
     The answer to each question will,  of course, depend on site specific
factors.  For example, sites with more heterogenous subsurfaces will
require more hydrogeologic information to provide a reasonable assurance
that well placements will intercept contaminant migration.  Likewise,
investigatory techniques that may be appropriate in one setting (given
certain waste characteristics and geologic features), may be
inappropriate in another.
     This chapter is designed to help enforcement officials answer the
above questions.  It identifies various investigatory techniques that are
necessary for an owner/operator to adequately characterize a site  and
explores the factors that enforcement officials should consider when
                                    1-1

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evaluating whether the particular investigatory program an owner/operator
used was appropriate in a given case.  Enforcement officials should also
find this chapter useful when constructing compliance orders that include
hydrogeologic investigations.
     1.1  Investigatory Tasks for Hydrogeologic Assessments
     In carrying out a hydrogeologic investigatory program, owner/
operators should accomplish two tasks:
     1.  define the subsurface geology/materials; and
     2.  identify ground-water flow paths and rates.
A variety of investigatory techniques are available to achieve these
goals and enforcement officials must evaluate whether the combination of
techniques used by the owner/operator was adequate given the site
specific factors at his/her facility.
     There are certain investigatory techniques that all owner/operators,
at a minimum, should have used to characterize their sites.  Table 1-1
illustrates the universe of techniques that an owner/operator may use to
perform hydrogeologic investigations.  Those techniques that the owner/
operator, at a minimum, should have used to define the subsurface geology
or identify ground-water flow paths are identified with astericks.
     Table 1-1 also presents preferred methods for presentation of the
data generated from a hydrogeologic assessment.  An owner/operator who
has performed the level of site characterization that is necessary to
design adequate ground-water monitoring programs will be able to supply
any of the outputs (cross sections, maps, etc.) listed in the last column
of Table 1-1 at an appropriate level of specificity.
     The owner/operator's investigatory program should have included
direct (e.g., borings, piezometer wells, geochemical analysis of soil
samples) methods of determining the site hydrogeology.  Indirect methods
(e.g., aerial photography, ground penetrating radar, resistivity).
4
                                    1-2

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especially geophysical studies, may provide valuable sources of informa-
tion that can be used to extrapolate geologic data between points where
measurements with direct methods were made.  However, pre-existing
information or indirect methods will not alone have provided the detailed
information necessary.  The owner/operator's investigatory program will
likely have combined the use of direct and indirect techniques and should
have resulted in the complete characterization of the facility, including
an identification of:
     •  the subsurface geology below the owner/operator's hazardous waste
        facility:
     •  the vertical and horizontal components of flow in the uppermost
        saturated zone below the owner/operator's site;
     •  the hydraulic conductivity of the uppermost saturated zone; and
     •  the vertical extent of the uppermost saturated unit down to the
        first confining layer.
The following sections outline the basic steps an owner/operator should
have followed to implement an adequate site hydrogeologic study, and
detail the methods that the owner/operator should have used to collect
and present site hydrogeologic data.
     1.2  Characterization of Subsurface Geology
     In order to adequately detail the subsurface geology of the site,
the owner/operator should have collected direct information identifying
the lithology and structural characteristics of the subsurface.  Indirect
methods of geologic investigation such as geophysical studies, may be
used to verify the evidence gathered by direct field methods but should
not be used as a substitute for them.  Geophysical studies such as
seismic reflection, seismic refraction, geophysical well logging, and
resistivity measurements may yield valuable information on the depth to
bedrock, the types of unconsolidated material present in the subsurface
soil and above bedrock, the presence of fracture zones or structural
                                    1-5

-------
discontinuity, and the depth to the water table.   Additionally, geophysi-
cal methods may have their greatest utility in correlating the continuity
of subsurface materials between boreholes.  However, geophysical methods
should have been used primarily to substantiate information obtained from
direct sources, and in order to adequately characterize the lithology and
geologic characteristics of the subsurface, the owner/operator should
have used direct means of gathering hard data concerning the subsurface
geologic constituents at the site.  Specifically,  all owner/operators
should have implemented a site characterization boring program sufficient
to characterize the subsurface geology below the the site.
     1.2.1  Site Characterization Boring Program
     The enforcement officer should determine whether an owner/operator's
boring program was adequate to gather the information necessary to
characterize the subsurface geology.  Such a program should have entailed
the installation of borings:
     •  at a preferred spacing of 300 feet.  (Boring spacing may vary
        from this horizontal distance based on criteria described in
        Table 1-2.)
     •  that have been drilled to the depth of the first confining unit
        below the uppermost zone of saturation.
     •  that have continuous sample corings that have been logged in the
        field by a qualified geologist.
     •  that have had sufficient laboratory analysis to provide
        information as to the petrographic variation, mineralogic
        variation, sorting (for sedimentary units), moisture content and
        intrinsic permeability of each geologic unit or soil zone.
     The final spacing between boreholes in an owner/operator's charac-
terization program will ultimately, of course, depend upon site specific
conditions.  Usually, the boring program will be a progressive investiga-
tion where results from initial phases of study will guide subsequent
decisions.  For example, spacings between borings in the early phase of
€
                                    1-6

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1-7

-------
the program may start at 300 feet.  The information subsequently
generated could dictate closer borings over part of the site and wider
spacings between borings on other parts of the site.
     The owner/operator should characterize site geology to the depth of
the first confining layer below the uppermost saturated zone or ten feet
into bedrock.  This requires borings to be drilled to this depth.  The
owner/operator should drill enough borings to this depth to establish
that the confining layer extends laterally across the entire site, is of
sufficient thickness, and is sufficiently impermeable to impede the
migration of contaminants to any stratigraphically lower, water-bearing
units.  (Refer to the glossary for the definition of confining layer.)
It should be noted by the enforcement official that chemical bridging and
transfer across, or chemical reaction with confining layer material, can
occur.  Therefore, the owner/operator should have addressed this problem
by considering chemical compatibility of site-specific waste types and
the geologic materials of the confining layer.
     All coring samples should have been logged in the field by a quali-
fied geologist (see glossary).  These sample corings should have been
collected with a shelby tube or split spoon sampler and represent a
continuous coring of the subsurface.  Drilling logs should have been
prepared which detail the following information:
     •  gross petrography (e.g., rock type) of each geologic unit;
     •  gross mineralogy of each geologic unit;
     •  gross structural interpretation of each geologic unit and
        structural features crossing geologic stratum bioturbation
        (e.g., fractures, gouge material, solution channels, buried
        streams or valleys, etc.) including, when applicable,
        identification of depositional material;
     •  development of soil zones and vertical extent and description of
        soil type;
     •  depth of water bearing unit(s) and vertical extent of each;
                                    1-8

-------
     •  depth and reason for termination of borehole; and

     •  depth and location of any contaminant encountered in bore-
        hole.  (Samples should have been collected and analyzed for
        Appendix VIII constituents in accordance with requirements of
        SW-846.)

Figure 1-1 identifies the minimum required information that should have

been included in a drilling log.  These items are marked with astericks.

     In addition to field descriptions as described above, the owner/
operator should have provided laboratory analysis of each geologic unit
and soil zone.  These analyses should contain the following information:

     •  mineralogy and mineralogic variation of each geologic unit (e.g.,
        microscopic analysis and other methods such as X-ray diffraction
        as necessary);

     •  petrology and petrologic variation of each unit (e.g. petrographic
        analysis, other laboratory methods for unconsolidated materials)
        to determine:

          - degree of crystallinity and cementation of matrix
          - degree of sorting, size fraction, textural variation
          - rock type(s)
          - soil type
          - approximate bulk geochemistry
          - existence of microstructures that may effect or indicate
            fluid flow

     •  moisture content and moisture variation of each soil zone and
        geologic unit; ar.d

     •  intrinsic permeability and variation of each soil zone and type
        and geologic unit in the unsaturated zone (indirect methods are
        not appropriate to determine hydraulic conductivity in the
        saturated zone, Section 1.3.2).

     A table which describes the laboratory analysis methods necessary to
provide adequate information to detail these laboratory parameters is
shown in Table 1-3.

     From a procedural standpoint, an owner/operator may opt to develop
a scheme for selecting borehole locations in a step-wise or progressive
                                    1-9

-------
                                FIGURE 1-1
                       FIELD BORING LOG INFORMATION
General
 •  Project name
*•  Hole name/number
*•  Date started and finished
*•  Geologist's name
*•  Driller's name
                                        •  Sheet number
                                       *•  Hole location; map and
                                           elevation
                                       *•  Rig type
                                           bit size/auger size
Information Columns

*•  Depth
*•  Sample location/number
 •  Blow counts and advance rate
                                       *•  Percent sample recovery
                                       *•  Narrative description
Narrative Description

 •  Geologic observations:
    *_
    *_
    *_
      rock type
   *- color
      gross mineralogy
      gross petrography
    - friability
   *- moisture content

•  Drilling Observations:

    - loss of circulation
   *- advance rates
    - rig chatter
   *- water levels
    - amount of air
      used

•  Other Remarks:
     - equipment failures
    *- possible sources of contamination
    *- deviations from drilling plan
    *- weather
*Indicates items that the owner/operator should record, at a minimum.
*- crystalinity
*- presence of
   carbonate (HCL)
*- fractures
*- solution cavities
*- bedding
                             *- drilling
                                difficulties
                             *- changes in drilling
                                method or equipment
*- depositional
   structures
*- organic content
*- odor
*- suspected
   contaminant
                            ammounts and type
                            of any liquids
                            used
                            running sands
                            caving/hole
                            stability
*_
*_
                                   1-10

-------
                                            TABLE  1-3

                          SUGGESTED  LABORATORY METHODS  FOR CORE SAMPLES
  Sample Origin
      Parameter
             Laboratory Method
                           Used to Determine
Unsaturated zone
Geologic formation,
unconsolidated
sediments, consoli-
dated sediments,
sol urn
Contaminated sample
corings (e.g.,  soils
producing higher
than background
organic vapor
readings)
Intrinsic permeability

Size fraction

Sorting
Specific yield
Specific retention

Mineralogy
Bulk geochemistry
Crystallinity
Roundness of grains
Bedding
Lamination
Jointing
Fracturing
Sorting
Solution features
Appendix VIII
 Parameters
(§261)
Falling head, static
 head test
Sieving
Settling measurements
Petrographic analysis
Column drawings
Centrifuge tests

Petrographic analysis
X-ray diffraction
Petrographic analysis
Petrographic analysis
Petrographic analysis
Petrographic analysis
Petrographic analysis
Petrographic analysis
Petrographic analysis
Petrographic analysis

SW-846
                                     Hydraulic conductivity

                                     Hydraulic conductivity

                                     Hydraulic conductivity
                                     Porosity
                                     Porosity

                                     Soil  type,  rock type,
                                      geochemistry,  poten-
                                      tial  flow paths
                                                  1-11

-------
approach.  A feature of this technique is that data and observations
derived from previous boreholes are used to establish the location for
the next boring.  In this way,  the general 300-foot borehole spacing
guideline may be varied depending on the conditions encountered and
logged in the previous boreholes.  Such a progressive boring program is
described below.
     First, the owner/operator should project a grid pattern with a
300-foot interval across the site.  Second, the owner/operator should
initiate the boring and site characterization program, at one of the grid
intersection points near the waste management area.  After the completion
of the first few borings, the owner/operator should check drill logs for:
     •  correlation of geologic profiles between soil borings;
     •  identification of zones of high potential hydraulic conductivity;
     •  indication of unusual or unpredicted geologic features such as
        fault zones, fracture traces, facies changes, dissolution
        features, buried channels, cross cutting structures, pinch out
        zones, etc.; and
     •  continuity of petrographic features such as sorting, grain size
        distribution, cementation, etc.
If the owner/operator is unable to adequately define such structural
anomalies, zones of potential high conductivity, or to correlate
petrographic features and/or geologic profiles between any two adjacent
boreholes then additional intermediate boreholes should be drilled.  The
suggested method would be to drill intermediate boreholes, at a spacing
of 150 feet and at successively shorter spacing intervals until the
criteria outlined in the above bulleted items was adequately addressed.
     On the other hand, if the bulleted parameters are achieved at the
300-foot spacing, it would be appropriate to switch to a wider spacing of
600 feet between adjacent boreholes.  If at the 600-foot interval the
criteria are again met, it would again be acceptable to switch to a wider
grid spacing.
                                   1-12

-------
     Figure 1-2 illustrates a site where an owner/operator initiated a
progressive boring program.  The first four borings were drilled in an
area adjacent to the site that the owner/operator considered to be down-
gradient and thus critical to his characterization program.  Drilling
indicated thick massive marine sediments below a thin poorly developed
soil zone.  Geologic units were highly correlated and indicated little or
no lateral variation in petrographic or structural components.  A bedrock
basement was identified in all borings and structural components of the
basement/sediment interface were well defined.  At this point the owner/
operator switched to a wider spacing of 600 feet between boreholes.
Additional borings indicated very little lateral variation and the owner/
operator was justified in terminating borings at a 1200-foot interval.
     At a second site, (see Figure 1-3) the owner/operator initiated his
soil boring in a similar manner to that described in the first example.
However, the geologic environment was more complex in nature, such as
that of a fluvio-glacial depositional environment.  Initial borings
indicated that the subsurface was highly variable.  Attempted correlation
of buried structural features of high permeability and potential confin-
ing layers were inconsistent between boreholes.  The owner/operator in
this case switched to a shorter boring spacing of 150 linear feet.  At
this interval, the owner/operator was able to define some continuity
between boreholes and structural features.  These were still erratic but
correlation between boreholes indicated that zones of high permeability
and low permeability had been defined.  Also at this point, the owner/
operator was able to roughly determine the general ground-water direc-
tional flow and decided to concentrate further studies at the downgradient
side of the waste management area.  The owner/operator,  at this point,
initiated a geophysical surface resistivity study at the downgradient
side of the waste management area and was able to support existing boring
data with structural geophysical interpretation.
                                   1-13

-------
              300'
 17
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                             14
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                            I
                    FACILITY BOUNDARY
                            LEGEND
                     FIRST PHASE CHARACTERIZATION BORINGS






                     SECOND PHASE CHARACTERIZATION BORINGS
FIGURE 1-2 PROGRESSIVE BORING APPROACH : SCENARIO 1
                 1-14

-------
                    300'
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                                        LEGEND
                             O FIRST • PHASE CHARACTERIZATION BORINGS




                             0 SECOND • PHASE CHARACTERIZATION BORINGS




^                               INDICATED DIRECTION OF GROUND-WATER

                               FLOW


                            ... GEOPHYSICAL TRAVERSE
FIGURE 1-3  PROGRESSIVE BORING APPROACH: SCENARIO 2


                      1-15

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     1.2.2  Interpretation of Subsurface Geology

     The enforcement official should review the owner/operator's geologic
characterization and verify:

     •  completeness of the narrative and the accuracy of the
        owner/operator's interpretation, and

     •  that the geologic assessment addresses or provides means to
        resolve any information gaps that may be suggested by the
        geologic data.

     In order to assess the completeness and accuracy of the owner/

operator's narrative, the enforcement geologist should:

     •  examine and evaluate the raw data;

     •  compare his own interpretation based on the raw data alone,with
        that of the owner/operator; and

     •  identify information gaps that relate to incomplete data and/or
        to narrative presentation.

     The enforcement officer should independently conduct the  following
tasks to support and develop his interpretation of the site geology:

     •  review drilling logs and identify major rock or soil types and
        establish their horizontal and vertical variability;

     •  construct representative cross sections from well log data;

     •  identify zones of suspected high permeability, or structures
        likely to influence contaminant migration through the unsaturated
        and saturated zones;

     •  review laboratory data and determine whether laboratory data
        adequately corroborates field data and that both are sufficient
        to define petrography and petrographic variation; and

     •  review mineralogic data and the owner/operator's assessment of
        general subsurface geochemistry and determine corroboration
        between analytic and field data.

     After the enforcement official has interpreted the geologic data,
the results should be compared to the results developed by  the

owner/operator.  The enforcement official should:
                                   1-16

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     •  identify information gaps between narrative and data. Determine
        whether resolution requires collection of additional data or
        re-assessment of existing data; and
     •  identify any information gaps that will effect the owner/
        operator's ability to have adequately located his/her moni-
        toring well system.
     1.2.3  Presentation of Geologic Data
     In addition to the generation and interpretation of site specific
geologic data, the enforcement officer should review the owner/operator's
presentation of data in geologic cross sections, topographic maps and
aerial photographs.  In part this requires that the enforcement officer
to review the data and determine qualitatively whether information is
accurate.
     A minimum of four geologic cross sections should be presented by
an owner/operator.  These cross sections should adequately depict major
geologic or structural trends and reflect geologic/structural features in
relation to ground-water flow.  As such, geologic cross sections should
delineate such features in an orthogonal boxwork (see Figure 1-4) but
nonlinear structural features or complex ground-water patterns may
necessitate additional cross sections and/or nonorthogonal cross section
presentation.
     On each cross section, the owner/operator should have identified:
the types and characteristics of the geologic materials present, the
contact zones between different geologic materials, zones of high
permeability or fracture, the location of each borehole, depth of
termination, the screen location, and depth to the zone of saturation.
If the owner/operator is unable to supply such details, the subsurface
study may be inadequate.  Figure 1-5 illustrates a typical, geologic
cross section.
     Additionally, surficial features may affect the subsurface hydro-
geology.  An owner/operator should have provided a surface topographic
                                   1-17

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GROUND-WATER
   FLOW
CROSS SECTION TRACES
                               WASTE
                              DISPOSAL
                               UNIT
                                                             CROSS SECTION TRACES
                                     PROPERTY BOUNDARY
                  SCALE (FEET)
         400
                      0 100* 200' 300' 400'
                                                           LEGEND
                                                            BORING
              FIGURE 1-4  GEOLOGIC CROSS SECTION SURVEY PLAN
                                   1-18

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map and aerial photograph of the site.  The topographic map should have
been constructed by a licensed surveyor and should provide contours at a
maximum two-foot contour interval, locations and illustrations of man-made
features (e.g., parking lots, factory buildings, drainage ditches, storm
drains, pipelines, etc.), descriptions of nearby water bodies and/or off
site wells, site boundaries, individual RCRA units, delineation of the
waste management areas, and well and  boring locations.  An example of a
site map is depicted in Figure 1-6.  An aerial photograph of the site
should depict the site and adjacent off-site features.  This photograph
should have the site clearly labeled.  In addition, surface water bodies
and adjacent municipalities or residences should be labeled.
     1.3  Identification of Ground-Water Plowpaths
     In addition to evaluating the owner/operator's characterization of
subsurface geology, enforcement officials must decide whether owner/
operators have adequately identified ground-water flowpaths.  To have
adequately identified flowpaths, owner/operators must have:
     •  established the direction of ground-water flow (including both
        horizontal and vertical components of flow);
     •  established the seasonal, temporal, and artificially induced
        (i.e., off-site production well pumping, agricultural use)
        variations in ground-water flow; and
     •  determined the hydraulic conductivities of the hydrogeologic
        units underlying their site.
In addition, enforcement officials must ensure that owner/operators used
appropriate methods for obtaining the above information.
     1.3.1  Determining Ground-Water Flow Directions
     To locate wells so as  to provide upgradient and downgradient well
samples, owner/operators should have a thorough understanding of how
ground water flows beneath  their facility.  Of particular  importance  is
the direction of ground-water flow and the impact  that external factors
                                    1-20

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(intermittent well pumping, temporal variations in recharge patterns,
etc.) may have on ground-water patterns.  In order for an owner/operator
to have assessed these factors, a program should have been developed and
implemented for precise well water level monitoring.  This program should
have been structured such that it provides precise well water level
measurements in a sufficient number of wells and at a sufficient
frequency to adequately gauge both seasonal average flow directions and
to account for seasonal or temporal fluctuation of flow directions.
     In addition to considering the components of flow in the horizontal
direction, a methodology or program should have been undertaken by the
owner/operator that accurately and directly assessed the vertical compo-
nents of ground-water flow.  Ground-water flow information should not
be based on indirect data alone.  Enforcement officials should review
independently an owner/operator's methodology for obtaining information
on ground-water flow and account for factors that may impact or
complicate ground-water flow at the facility.  The following sections
detail the methods by which an owner/operator should have assessed the
vertical and horizontal components of flow at the site.
     1.3.1.1  Ground water level measurements
     In order for the owner/operator to have initially determined the
elevation of the water table in any boring well, several criteria should
have been considered by the owner/operator.
     •  The well casing height should have been measured by a licensed
        surveyor to an accuracy of 0.1 feet.  This may have required the
        placement of a geologic benchmark on the facility property.
     •  All well water level measurements from boring or piezometer wells
        used to construct a single potentiometric surface should have
        been collected within a twenty-four hour period.
     •  The method used to measure well water levels should have been
        adequate to attain an accuracy of 0.1 feet.
                                   1-22

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     •  Well water levels should have been allowed to stabilize for
        a minimum of twenty-four hours after well construction and
        development, prior to measurement.  In low yield situations,
        recovery may take longer.
     If an owner/operator cannot produce accurate documentation or
provide assurance that these criteria were met during the collection of
well water level measurements, this may indicate that the generated
information may be of questionable validity.
     1.3.1.2  Interpretation of ground-water level measurements
     After the enforcement official has assured that the well water level
data is valid, he should proceed to independently interpret the
information.  The enforcement official should:
     *  use the owner/operator's raw data to construct a potentiometric
        surface map (see Figure 1-7).  The data used to develop the
        potentiometric map should be data from wells screened at
        equivalent stratigraphic horizons in the saturated zone;
     •  compare this data with that of the owner/operator's and deter-
        mine whether the owner/operator has accurately presented the
        information and determine if the information is sufficient to
        describe ground-water flow trends; and
     •  identify any information gaps.
     In reviewing this information, the enforcement officer should now
have an approximate idea of the general flow direction; however, in order
to have properly located monitoring wells, the owner/operator should have
established flow directions in both the horizontal and vertical directions.
     1.3.1.3  Establishing vertical components of ground-water flow
     In order for the owner/operator to have determined the direction of
flow, vertical components of flow must have been directly determined.  To
illustrate the importance of vertical flow in determining overall ground-
water flow, an example is illustrated in Figure 1-8.  In this situation,
the owner/operator has constructed a downgradient monitoring well in what
                                   1-23

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would first appear to an appropriate location.  The well site selection
was based on a potentiometric surface developed from a data base of well
measurements.  The owner/operator determined the general direction of
flow utilizing this information.  Although this well placement may have
at first appeared to be appropriate, the flowpaths below the hazardous
waste unit are almost vertical and the well as depicted here would not
intercept a contaminant flowpath from the contaminant source.  Thus, it
is necessary that the owner/operator assess the vertical components of
flow at the regulated site as well as horizontal components.
     In order to collect this information the owner/operator should have
utilized direct means to determine vertical flow components.  This will
have required the installation of piezometers in well clusters.  In order
to have obtained reliable measurements the following criteria should be
considered in the placement of piezometer clusters.
     •  Information obtained from multiple piezometer placement in single
        boreholes may generate erroneous data.  Placement of vertically
        nested piezometers in closely spaced separate boreholes is the
        preferred method.
     •  Piezometer measurements should have been collected within a
        twenty-four hour period if measurements are to be used in any
        correlative presentation of data.
     •  Piezometer measurements should have been determined along a
        minimum of two vertical profiles across the site.  These profiles
        should be cross sections roughly parallel to the direction of
        ground-water flow indicated by the potentiometric surface.
     When reviewing piezometer information obtained from multiple
placement of piezometers in single boreholes, the enforcement official
should closely scrutinize the construction details for the well.  It is
extremely difficult to adequately seal several piezometers at discrete
depths within a single borehole and special design considerations should
have been considered by the owner/operator.  If information is not
available that details design features, it may indicate that adequate
                                   1-26

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construction considerations have not been used.  Placement of piezometers
in closely spaced well clusters, where piezometers have been screened at
different, discrete depth intervals is more likely to produce accurate
information.  Additionally, multiple well clusters sample a greater
proportion of the aquifer and thus may provide a greater degree of
accuracy for considerations of vertical potentiometric head in the
aquifer as a whole.
     The information obtained from the piezometer readings should have
been used by the owner/operator to construct flow nets (see Figure 1-9).
These flow nets should include information as to piezometer location and
depth and width of screening.  The flow net in Figure 1-9 was constructed
from information obtained from piezometer clusters screened at different,
discrete intervals.  The construction of contours is straightforward and
the enforcement official should be able to verify the accuracy of the
owner/operator's presentation.  The enforcement official should either
construct a flow net independently from the owner/operator's data or
spot-check the owner/operator's presentation.  It is also important to
verify that the screened interval is accurately portrayed and to determine
whether the piezometer is actually monitoring the water table elevation
caused by the hydrostatic pressure of the desired water bearing unit.
     If there is reasonable concurrence between the information presented
by the owner/operator and the enforcement officer's interpretation, the
enforcement officer should next interpret the flow directions from the
waste management area.
     1.3.1.4  Interpretation of flow direction
     In considering flow directions established by the owner/operator,
the enforcement official should have first:
     •  established that the potentiometric surface measurements are
        valid; and
     •  established that the vertical components of flow have been
        accurately depicted and are based on valid data.
                                   1-27

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     At this point general considerations of ground-water flow may be
estimated.  The enforcement officer should construct vertical intercepts
with the rOtentiometric contours for both the potentiometrie surface map
and from flow nets.  Once the vertical and horizontal directions of flow
are established (from points of higher head to lower head), it is possible
to estimate where monitoring wells will most likely intercept contaminant
flow in the vertical plane.  To consider the placement that will most
effectively intercept contaminant flow, a consideration of hydraulic
conductivity is required.
     1.3.2  Seasonal and Temporal Factors:  Ground-Water Flow
     It is important to note if the owner/operator has identified and
assessed factors that may result in short-term or long-term variations in
ground-water level and flow patterns.  Such factors that may impact
ground-water conditions include:
        off-site well pumping;
        tidal processes or other intermittent natural variations (e.g.,
        river stage, etc.);
        on-site well pumping;
        off-site, on-site construction or changing land use patterns;
        deep well injection; and
        seasonal variations.
     Off-site or on-site well pumping may affect both the rate and
direction of ground-water flow.  Municipal, industrial or agricultural
ground-water use may significantly alter or change ground-water flow
patterns and levels over short or long periods of time.  Pumpage may be
seasonal or dependent upon other complex water use patterns.  The effects
of pumpage thus may reflect time-continuous or discontinuous patterns.
Well water level measurements must have been frequent enough to detect
such water use patterns.
     Natural processes such as riverine, estuarine, or marine tidal move-
ment may result in variations of well water levels and/or ground-water
quality.  An owner/operator should have documented the effects of such
                                   1-29

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patterns.  Seasonal patterns have a significant affect on water table
levels and ground-water flow.  Short term recharge patterns may affect
ground-water flow patterns that are markedly different from ground-water
flow patterns that are determined by seasonal averages.  An owner/operator
should have gauged such transitional patterns.
     Additionally, an owner/operator should have implemented means for
gauging long term effects on water movement that may result from on-site
or off-site construction or changes in land-use patterns.  Development
may effect ground-water flow by altering recharge or discharge patterns.
Examples of such changes might include the paving of recharge areas or
damming of waterways.
     In reviewing the owner/operator's assessment of ground-water flow
patterns, the enforcement officer should consider whether the owner/
operator's program was sensitive to such seasonal or temporal variations.
An owner/operator should have, in effect, determined not only the location
of water resources but the sources and source patterns that contribute to
or effect ground-water patterns below the regulated site.
     1.3.3  Determining Hydraulic Conductivities
     In addition to defining the direction of ground-water flow in the
vertical and horizontal direction, the owner/operator must identify areas
of high and low hydraulic conductivity (K) within each formation.  Varia-
tions in the hydraulic conductivity of subsurface materials can create
irregularities in ground-water flow paths.  Areas of high hydraulic
conductivity represent areas of greater ground-water flow and, if contami-
nants are present, zones of potential migration.  Therefore, information
on hydraulic conductivities is required before owner/ operators can make
reasoned decisions regarding well placements.
     Enforcement officials should review the owner/operator's hydrogeo-
logic assessment report to ensure that it contains data on the hydraulic
conductivities of the various geologic materials underlying the site.
                                   1-30

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In addition, enforcement officials should review the method the owner/
operator used to derive the conductivity values.  It may be beneficial to
use analogy or laboratory methods to corroborate results of field tests;
however, only field methods provide direct information that is adequate
to define the hydraulic conductivity.
     Hydraulic conductivity can be determined in the field using either
single or multiple well tests.  Single well tests, more commonly referred
to as slug tests, are performed by suddenly adding or removing a slug
(known volume) of water from a well or piezometer and observing the
recovery of the water surface to its original level.  Similar results can
be achieved by pressurizing the well casing, depressing the water level,
and suddenly releasing the pressure to simulate removal of water from the
well.
     When reviewing information obtained from slug tests, the enforcement
official should consider several criteria.  First, slug tests are run on
one well and, as such, the information obtained from single well tests is
limited in scope to the geologic area directly adjacent to the well.
Second, the vertical extent of screening will control the part of the
geologic formation that is being tested during the slug test.  That part
of the column above or below the screened interval that has not been
tested during the slug test will not have been adequately tested for
hydraulic conductivity.  Third, the methods that the owner/operator used
to collect the information obtained from slug tests should be adequate to
measure accurately parameters such as changing static water (prior to
initiation, during, and following completion of slug test), the amount of
water added to, or removed from, the well, and the elapsed time of
recovery.  This is especially important in highly permeable formations
where pressure transducers and high speed recording equipment should be
used.  Lastly, the owner/operator's interpretation of the slug test data
should be consistent with the existing geologic information (boring log
                                   1-31

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data).  It is, therefore, important that officials examine the owner/
operator's program of slug testing to ensure that enough tests were run
to provide representative measures of hydraulic conductivity and to
document lateral and vertical variation of hydraulic conductivity in the
hydrogeologic subsurface below the site.
     Multiple well tests, more commonly referred to as pump tests, are
performed by pumping water from one well and observing the resulting
drawdown in nearby wells.  Multiple well tests for hydraulic conductivity
are advantageous because they characterize a greater proportion of the
geologic subsurface and thus provide a greater amount of detail.  Multiple
well tests are subject to similar constraints to those listed above for
single well tests,  some additional problems that should have been con-
sidered by the owner/operator conducting a multiple well test include:
(1) storage of potentially contaminated water pumped from the well system
and (2) potential effects of ground-water pumping on existing waste
plumes.  The enforcement official should closely consider the geologic
constraints that the owner/operator has used to interpret the pump-test
results.  Incorrect assumptions regarding geology may translate into
incorrect estimations of hydraulic conductivity.
     In reviewing the owner/operator's hydraulic conductivity measure-
ments, the enforcement officer should use the following criteria to
determine the accuracy or completeness of information.
     •  Values of hydraulic conductivity between wells should not exceed
        one order of magnitude difference.  If values exceed this
        difference the owner/operator may have not provided enough
        information to sufficiently define a potential flowpath.
     •  Hydraulic conductivity for multiple well tests should be
        considered the preferred method.  They provide more complete
        information because they characterize a greater portion of the
        subsurface.
     •  Use of single well tests will require that more individual tests
        at different locations to sufficiently define hydraulic
        conductivity variation across the site.
                                   1-32

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     •  Hydraulic conductivity information generally provides average
        values for the entire area across a well screen.  For more depth
        discrete information, well screens will have to be shorter.  If
        the average hydraulic conductivity for a formation is required,
        entire formations may have to be screened.
     It is important that hydraulic conductivity measurements define
hydraulic conductivity both in a vertical and horizontal manner across an
owner/operator's regulated site.  In assessing the completeness of an
owner/operator's hydraulic conductivity measurements, the enforcement
official should also consider results from the boring program used to
characterize the site geology.  Zones of high permeability or fractures
identified from drilling logs should have been considered in the
determination of hydraulic conductivity.  Additionally, information from
coring logs can be used to refine the data generated by slug or pump
tests.
     1.4  Identification of the Uppermost Aquifer
     The owner/operator is required to monitor the uppermost aquifer
beneath the facility.  Enforcement officials, therefore, should ensure
that the owner/operator has correctly identified the uppermost aquifer.
Proper identification of the uppermost aquifer is critical to ensure
that monitoring wells are installed in the appropriate stratigraphic
horizon(s).
     The uppermost aquifer extends from the water table to the first
confining layer (or ten feet into bedrock) and includes any overlying
perched zones of saturation.  The identification of the confining layer
is an essential facet of the definition of uppermost aquifer.  There
should be no interconnection, based upon pumping tests, between the
uppermost aquifer and lower aquifers.  Consequently, the uppermost
aquifer includes all interconnected water-bearing zones overlying the
confining layer.
     When reviewing an owner/operator's hydrologic data and the deci-
sions the owner/operator has made regarding the identification of the
                                   1-33

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uppermost aquifer, the enforcement official should keep two important
points in mind.  First, the owner/operator should consider the defini-
tion of uppermost aquifer to encompass all water-bearing zones that
serve as pathways for contamination migration including perched zones of
saturation.  Saturated formations, even those consisting of relatively
impermeable materials, should be considered as part of the uppermost
aquifer.*  Second, the owner/operator should not consider the quality or
use of ground water as a factor in the identification of the geometric
dimensions of the uppermost aquifer.  Even though a saturated formation
may not be presently in use or may contain water not suitable for human
consumption, it may act as a pathway for contaminant migration and thus
is subject to monitoring.
     In all cases, the obligation to assess any hydraulic interconnections
and the proper definition of the uppermost aquifer rests with the owner/
operator.  The owner/operator should be able to prove that confining unit
is of sufficient impermeability to prevent the passage of contaminants to
saturated, stratigraphically lower units.
     The following examples illustrate geologic settings wherein hydrau-
lic interconnection must be demonstrated before proper identification of
the uppermost aquifer may be made.  The examples are not intended to be
exhaustive in the situations they portray rather they are meant to provide
a sample of geologic settings that result in hydraulic interconnection.
     Figure 1-10 illustrates a site that preliminary drill logs indicated
was underlain by a confining layer of unfractured, continuous clay.
(Note:  the actual geologic conditions are pictured for purposes of
clarity in the figure.)  In order to confirm whether the clay layer was
*Chapter Two describes criteria useful in identifying which  portions of
 the uppermost aquifer that should be screened.  It may not be desirable
 for the owner/operator to screen wells in saturated, low permeability
 formations even though, technically, these formations are part of the
 uppermost aquifer.  Other formations may offer a higher probability of
 contaminant movement and thus should be selected for monitoring.
                                   1-34

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ELEVATION
   MSL

   - 460'
   - 350'
   - 300'
   - 260'
   - 200'
DRILL DRILL
CORE  CORE
NO. 3  NO. 5
                                .'• '••."::;•. .'.• FINE GRAINED SAND •'
                                                                              ------------- CLAY .-_—_-
   L 150'
                                                   .MEDIUM GRAINED :
                                                         SAND      ':
                     FINE GRAINED SAND
                                                                         ;.V-'::VV. •:•.•';; FINE GRAINED
                                                                         :-.i.-^::::-.:l-    SAND
                                             ^CRYSTALLINE BASEMENT
                                                                                                     WATER
                                                                                                     TABLE
               I
              100
                     50
         1
        50
 I
100
             FIGURE  1-10   EXAMPLE OF  HYDRAULIC INTERCONNECTION  BETWEEN
                             WATER - BEARING UNITS
                                                   1-35

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continuous or discontinuous, the owner/operator conducted a pump test.
A well at drill point No. 5 was screened at the uppermost part of the
water table.  Another well at drill point No. 3 was located closeby and
screened below the clay layer.  Measurable drawdown was observed in the
upper well when the well below the confining was pumped.  This indicated
that the confining unit was not of sufficient impermeability to serve as
a significant boundary to contaminant flow.  In this case, the water
bearing unit below the clay layer as well as the formation above the clay
layer are both part of the uppermost aquifer.
     In Figure 1-11, the owner/operator drilled test borings through silt
and limestone formations into a sandstone unit.  In the initial corings,
no indication of fracturing of the limestone unit was observed.  The
owner/operator initially assumed that the limestone unit was dipping at
a moderate slope due to differing levels of contact.  However, as illus-
trated by the figure, actual conditions involve fracturing of the lime-
stone formation (additional corings and geophysical studies detected
fracture zones).  These fractures represent hydraulic interconnection
between the upper gravelly silt layer and the sandstone formation below
the limestone unit.  The uppermost aquifer, therefore, includes the
gravelly silt formation, the limestone formation, and the sandstone
formation.
     Figure 1-12 illustrates a situation where perched water zones lie
above the ground-water table.  The uppermost aquifer includes the perched
water zones and that part of the sand formation from the top of the water
table to the top of the bedrock.
     In Figure 1-13, initial test borings indicated that horizontal sandy
units were underlain by a consolidated well-cemented, impermeable, sand-
stone unit.  Initial borings did not indicate the presence of the buried
structural anticline.  The owner/operator incorrectly assumed that the
sandstone unit was a confining layer that extended across the subsurface
                                   1-36

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                                      300'
    200 -i
    150 H
    100 -
     50 -
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                                FRACTURED LIMESTONE
                                                                      WATER
                                                                      TABLE
          i      i  rw i rTrt      i      i
         100'   50'     0'     50'    100'
FIGURE  1-11.  AN EXAMPLE OF HYDRAULIC INTERCONNECTION CAUSED BY FRACTURING
                                      1-37

-------
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1-38

-------
ELEVATION
 M.S.L.
 p- 700'
                                   300'
 -600'
 -500
 — 400
 ^-300'
    BORE HOLE
                                    BORE HOLE
                             .••V  WASTE UNIT >r.
                                SANDY ZONE
                             I DOLOMITE   K
                                 (SATURATED)
                                                                      WATER
                                                                      TABLE
       I
      100'
 I
50'
  I "•
  0'
SCALE
                           50'
                                  100'
  FIGURE 1-13.  AN EXAMPLE OF AN UNDETECTED, STRUCTURALLY COMPLEX
                UPPERMOST AQUIFER
                                       1-39

-------
below the site.  A dolomite unit,  in contact with the unconsolidated
sandy silts, and directly below the waste unit, is saturated and highly
permeable.  Additional investigation including pump tests, borings,
and/or geophysical analysis better defined the subsurface.  The uppermost
aquifer, in this case, includes the anticlinal formations.
     In Figure 1-14, unconsolidated units are underlain by a consolidated
series of variable, near-shore, shallow marine sediments.  The owner/
operator has installed two borings near the waste management unit to
identify the uppermost aquifer.  Interpretation of these borings indicate
that the unconsolidated units are underlain by a well cemented limestone
of very low permeability.  However, an undetected sandstone unit, that is
laterally continuous with the limestone unit, is highly permeable and
saturated and represents an undetected portion of the uppermost aquifer.
Interpretation of the depositional environment of the limestone unit,
coupled with a knowledge of the local or regional geology should have
been used in addition to other investigatory techniques to establish the
presence of the transitional lateral structural feature and thus properly
define the uppermost aquifer.
     A special case, and one that should receive considerable considera-
tion by the enforcement officer, is the situation in which two saturated
units are separated by a confining unit that may be chemically reactive
with the leachate from a regulated unit. Such a situation is illustrated
in Figure 1-15.  Two considerations may apply to such a problem:
     •  Is the subsurface above the confining layer potentially reactive
        with the leachate such that it will significantly alter the
        leachate characteristics prior to contact with the confining unit?
     •  Is the reaction with the confining layer going to significantly
        affect the hydraulic conductivity of the water-bearing unit?
     Another special case that should be considered by the enforcement
official is the possibility that existing wells may provide avenues  for
                                   1-40

-------
 NEARSHORE
   FACIES
                                                                OFFSHORE
                                                                  FACIES
                       L , I  , I  . I .  I ,  I . I  . I  . I
                                     "—r LIMESTONE ,  ' ,  I i  ' , I
       550-
       500 -I
            150'
 I
150'
FIGURE 1-14. AN EXAMPLE OF AN UNDETECTED PORTION OF THE UPPERMOST AQUIFER
            (PERMEABLE SANDSTONE UNIT NEAR A COASTAL AREA)
                                     1-41

-------
         BORING
                                               MONITORING

                                                  WELL
                                                CLUSTER
                                                          BORING
Hi^i^i^^SSi^SiS CALCIUM RICH CLAY K - io~7 55^^^-psgS
                                                         rn"Vi"Vr»ii1" LI'I'•.::•'iV

                                                         »Pi;#nii;-fc:£--frr;:fl;ii;

                                                               LEGEND
                                                           I   WELL AND SCREEN
                                                           •
                                                           •



                                                          10'  SCREEN LENGTH






                                                          ..?.«V»ATER TABLE
   FIGURE 1-15
EXAMPLE OF A CONTAMINANT THAT MAY AFFECT THE QUALITY

              OF A CONFINING LAYER


                        1-42

-------
hydraulic communication between hydrogeologic units.  This is of special
importance when considering a site where a contaminant plume may have
migrated downgradient such that the plume approaches off-site wells.
Such wells may not have been constructed in a manner sensitive to
problems of cross-contamination between aquifers (see Chapter Four).
In such an instance, the off-site wells may have to be plugged and
replaced with appropriately designed wells.
                                   1-43

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                                              CHAPTER TWO
                                PLACEMENT OF DETECTION MONITORING WELLS

                    The purpose of this chapter  is to examine criteria the enforcement
               official should use in deciding  if the owner/operator has  made proper
               decisions regarding number and  location of detection monitoring wells.
               In evaluating the design of an owner/operator's detection  monitoring
               system,  the enforcement official  must examine the placement of upgradient
               and downgradient monitoring wells relative to hazardous waste management
               units,  the spacing between wells, and the  depths at  which  wells are
               screened.  The minimum number of  monitoring wells an owner/operator may
               install  in a detection monitoring system is four—one upgradient well and
               three downgradient wells.  Typically, site hydrogeology is too complex
               for the  minimum number of wells  to prove adequate in achieving the
               performance objectives of a detection monitoring system.
                    Chapter One described the  level of hydrogeologic characterization
               that owner/operators should conduct at their sites.   Collection and
               analysis of this data is crucial  to making proper decisions regarding
               the placement of wells and well  clusters and the selection of screened
               intervals for individual wells.   It is likely that the enforcement
!               official may confront situations  where the owner/operator  has collected
i
;               little or no site hydrogeologic  information or has relied  exclusively
\               on regional data to design a monitoring system.  In this situation, the
1               enforcement official should question the decisions the owner/operator has
i               made regarding well placement and screen depths and should require the
,               owner/operator to collect additional site information.
1                    Upgradient monitoring wells  provide background ground-water quality
t
               data in  the uppermost aquifer.   Upgradient wells should be (1) located
               beyond the upgradient extent of  contamination from the hazardous
               waste management unit so that they reflect background water quality,
                                                  2-1

-------
(2) screened at the same stratigraphic horizon(s) as the downgradient
wells to ensure comparability of data, and (3) of sufficient number to
account for heterogeneity in background ground-water quality.
     Downgradient wells must be located, screened, and sufficiently
numerous to provide a high level of certainty that releases of hazardous
waste or hazardous waste constituents from the hazardous waste management
unit(s) to the uppermost aquifer will be immediately detected.  Deter-
mination of the appropriate number of wells to be included in a detection
monitoring system hinges on the horizontal spacing between well locations
and the vertical sampling interval of individual wells.  Downgradient
monitoring wells must be located at the edge of the hazardous waste
management units.  Distance between wells is chiefly a function of
spatial heterogeneity of a site.  The consideration of site specific
conditions to evaluate well spacing is described in Section 2.1.  The
depth interval(s) over which downgradient monitoring wells should be
screened is a function of (1) geologic factors influencing the potential
contaminant pathways of migration to the uppermost aquifer, (2) chemical
characteristics of the hazardous waste controlling its likely movement
and distribution in the aquifer, and (3) hydrologic factors likely to
have an impact on contaminant movement.  The consideration of these
factors in evaluating the design of detection monitoring systems is
described in section 2.2.
     It is important to keep in mind that a properly designed detection
monitoring system will provide a high level of assurance that contaminant
leaks will be immediately detected.  RCRA does not, however, require
complete certainty that all  leaks be immediately detected.  A sufficient
number of detection monitoring wells screened at  the proper depths must
be installed by  the owner/operator to ensure  that his  ground-water
monitoring system guarantees an acceptably high  level  of certainty  that
contaminant leakage will be  immediately detected.  Although every
                                    2-2

-------
               detection monitoring system must  ultimately be judged against  site
'               specific conditions, there are a  number of criteria that  enforcement
               officials can apply to ensure that  detection monitoring systems satisfy
'               the RCRA regulatory requirements.   This chapter examines  those criteria
1               and provides examples on how enforcement officials can apply criteria in
               various hydrologic situations.
i                    2.1  Placement of Downgradient Detection Monitoring  Wells
!
1                    This section describes criteria the enforcement official  may use to
i
i               evaluate decisions the owner/operator has made regarding  placement of
               downgradient wells.  Specifically,  Section 2.1.1 describes  criteria for
               evaluating the location of downgradient wells relative to waste manage-
               ment areas.   Section 2.1.2 describes criteria for evaluating horizontal
               spacing between downgradient detection monitoring wells.  Section 2.1.3
               describes criteria for evaluating the depth of wells and  vertical
               sampling intervals.
                    2.1.1  Location of Wells Relative to Waste Management  Areas
                    In order to be able to immediately detect leaks should they occur,
               the owner/operator should install downgradient detection  monitoring wells
               immediately  adjacent to hazardous waste management units.   In  a practical
               sense,  this  means the owner/operator should install detection  monitoring
               wells as close as physically possible to the edge of hazardous waste
               management unit(s).  The two drawings in Figure 2-1 (A and  B)  illustrate
               the concept  of the placement of wells immediately adjacent  to  hazardous
               waste management unit(s).   Note how the placement of wells  relative to
               the units shifts as a function of the direction of ground-water flow.
                    In geological settings exhibiting interbedded unconsolidated sands,
               silts,  and clays (e.g.,  alluvial  facies) where the water  table is deep-
               seated,  the  lateral component of  contaminant migration may  carry it
               beyond the ground-water  monitoring  system before contaminants  reach
                                                  2-3

-------
                               GROUND-WATER
                                    FLOW


HAZARDOUS
WASTE MANAGEMENT
AREA A
-1
1
|
1
L
                                             LIMIT OF WASTE
                                             MANAGEMENT AREA

	 1
1
1

1
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HAZARDOUS WASTE
MANAGEMENT AREA B















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MANAGEMENT
AREA A


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                                             LIMIT OF WASTE
                                             MANAGEMENT AREA
GROUND-WATER
     FLOW

1
I
1
1


HAZARDOUS WASTE
MANAGEMENT AREAS
                                                    LEGEND
                                                   MONITORING WELL
  FIGURE 2-1.  DOWNGRADIENT WELLS IMMEDIATELY ADJACENT TO
              HAZARDOUS WASTE MANAGEMENT LIMITS
                              2-4

-------
               ground water,  and therefore beyond detection.   The owner/operators could
               institute a program of vadose zone monitoring as a supplement to the
               ground-water monitoring program in such cases to provide immediate
               detection of any release(s) from the hazardous waste management area.
               Volatile organics which escape to the vadose zone, for instance, may be
               detected and characterized through soil gas analysis.
                    2.1.2  Horizontal Spacing Between Downgradient Monitoring Wells
                    An owner/operator's downgradient detection monitoring wells must be
               spaced closely enough together to assure that the ground-water monitoring
               system guarantees an acceptably high level of certainty that contaminant
               leakage will be immediately detected.  The judgment as to whether the
               owner/operator has spaced detection monitoring wells close enough
               together does, of course, require analysis of site-specific conditions.
               Table 2-1 illustrates factors the enforcement official may use to decide
               if the owner/operator has made proper spacing decisions.  These factors
               cover a variety of physical and operational aspects relating to the
               facility including hydrogeologic setting, facility design, waste
               characteristics and climate.  The enforcement official should consider
               all factors described in Table 2-1 when evaluating well spacing.
i                    The Agency has selected 150 feet as the point of departure from
,               which well spacing may be compressed or expanded.  By using the 150-foot
:               spacing number as a point of departure and evaluating site specific
1               factors, the enforcement official should be able to judge the ability of
i
i               the owner/operator's monitoring system to immediately detect contaminant
,               leakage.  It should be noted that the 150-foot number is not one that
               enforcement officials should dogmatically apply.  Site specific condi-
1               tions should always drive decisions.  In some cases, closer spacing is
               needed over all or over part of the site.  In others, a wider spacing
               is adequate.  In any event, the enforcement official is ultimately
               responsible for ensuring that well spacings are adequate given site
                                                   2-5

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              conditions.   Final determination of adequate spacing will often come
              after comprehensive technical negotiations with the owner/operator in
              which each factor relating to spacing is evaluated and applied to spacing
              decisions.  The enforcement official should, in these cases, remember
              that the 150-foot number is a starting point for negotiation and that the
              enforcement  official is well within his authority to insist on closer
              spacing or to allow wider spacing.  The following examples illustrate how
              site-specific factors as described in Table 2-1 may affect well spacing.
                   Figure  2-2 illustrates a facility which contains both a landfill and
              a surface impoundment.  In this example, site geology is simple and
              homogeneous.  The landfill has received very little liquid waste and its
              design is well documented.  The surface impoundment contains a large
              volume of liquid waste.  Monitoring wells around the landfill are spaced
              225 feet apart because of simple and homogeneous site geology.  Monitor-
              ing wells around the surface impoundment are spaced 75 feet apart since
              there exists a greater potential for the generation of narrow contaminant
              plumes through holes in the liner propelled by the intrinsic head of the
              liquid waste in the impoundment.
't                   The two drawings in Figure 2-3 illustrate well placement based upon
              surficial stratigraphic complexity.  In drawing A, the landfill is com-
i
i              pletely situated on homogenous geology allowing the average well spacing
              to prevail.   Drawing B shows a facility that is situated over heterogenous
|              geology where well spacings need to be altered to account for changes in
1              lithology.  Monitoring well spacing in the sand and gravel formation
I
i              should be closer than that in the clay-silt formation.  The potential for
.              the escape from detection of more rapidly migrating narrow plumes,
|              especially through gravel seams, is higher in sand and gravel formations
              than in clay-silt formations which are characterized by lower hydraulic
              conductivities and higher diffusivities.  Figure 2-3 illustrates how well
              spacing should change to reflect the different lithologic units.  The
              monitoring wells in the clay and silt are spaced at 175 feet apart.
                                                  2-7

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                                                        GROUND-WATER
                                                            FLOW
                                                   BOUNDARY OF
                                                   WASTE
                                                   MANAGEMENT
                                                   UNIT
                                                SURFACE
                                              IMPOUNDMENT
GRAVELY SANDY TILL
                                       GRAVELY
                                         SAND
     FIGURE 2-2. WELL SPACING BASED UPON WASTE CHARACTER

                               2-8

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                                                                    GROUND-WATER

                                                                    f   FLOW
CLAY
SILTY
SAND
                                         LANDFILL

WASTE MANAGEMENT
      AREA
                                                   150'
                                GROUND-WATER
                                •   FLOW
                                T
                                                              LEGEND
                                                          •  MONITORING WELLS

                                                          O  BACKGROUND WELLS

                                                          l\.  PROPERTY LINE
              FIGURE 2-3.  WELL SPACING BASED UPON SITE GEOLOGY
                                       2-9

-------
     Figure 2-4 illustrates a facility where a landfill is situated on
a small hilltop in sandy-silt overlying glacial till.  The ground-water
movement at the landfill is radial in all directions due to the induced
hydraulic gradients caused by the mound.  The site characterization data
indicates more permeable fill on the edge of the facility.  The swamp to
the southeast is recharged from the landfill area.  Since the discharge
of the local ground water is into the swamp, closer well spacing is
necessary to monitor potential discharge in that area.  Note that since
contaminants may move from this site in any radial direction that
detection monitoring wells should ring the unit.
     Figure 2-5 illustrates a situation where permeabilities are low
   -4
(10   cm/sec) except in one area of the site which has higher permea-
bility (10   cm/sec) which may be indicative of a preferential flow
pathway.  Closer well spacing is required in the area of preferential
flow.
     Figure 2-6 illustrates an unlined surface impoundment located on
regularly-spaced nearly vertical fractures in consolidated siltstone.
The wells should be located to intercept major fractures.  To ensure
that all levels are monitored, additional wells are  located downgradient
in the low permeable rock matrix.  The wells (Nos. 1  through 6) appearing
to be upgradient of the facility are actually downgradient due to the
orientation of the fractures.
     Figure 2-7 illustrates two waste disposal units  on the same facility.
Waste Unit A is an impoundment that is  15 years old,  waste Unit B is a
5-year old landfill.  The site is located on simple homogenous geology
                                  -3      -4
with a moderate permeability of  10   to  10   cm/sec.  Because of the age
of Unit  A and  the presence of surface  liquids,  there  exists a greater
probability of a contaminant  release;  therefore wells need  to be much
closer  together  than  the newer Waste Unit B.
                                    2-10

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                           GROUND-WATER
                                FLOW
                                                     LEGEND
                                                    MONITORING WELLS


                                                    BACKGROUND WELLS


                                                    PROPERTY LINE
FIGURE 2-4. WELL PLACEMENT BASED UPON LOCALLY INUNDATED AREAS
                                 2-11

-------
                         GROUND-WATER
                             FLOW
 O  LIMITOFQ
WASTE MANAGEMENT
      AREA
GRAVELY
 SILTY-
 SAND
                                                                  ADDITIONAL
                                                                    WELLS
                                                                      NEEDED
                                                                        HERE
LEGEND
*
PL
BACKGROUND WELLS
MONITORING WELLS
ADDITIONAL WELLS
PROPERTY LINE
              FIGURE 2-5.  WELL PLACEMENT BASED UPON A CHANGE OF
                          PREFERENTIAL ROUTES OF MIGRATION
                                        2-12

-------

                                                     GROUND-WATER
                                                          FLOW
             FACTORY
                                         SURFACE
                                       IMPOUNDMENT
                                                SILTSTONE
LEGEND
o
•
n.
BACKGROUND WELL
MONITORING WELL
PROPERTY LINE
FIGURE 2-6. WELL PLACEMENT BASED UPON STRUCTURAL FRACTURING

                                2-13

-------
                                                  GROUND-WATER
                                                      FLOW
                        SURFACE
                      IMPOUNDMENT
FIGURE 2-7.  WELL PLACEMENT BASED UPON AGE AND WASTE CHARACTER
                               2-14

-------
     2.2  Depth of Veils/Vertical Sampling Interval(s)
     Site-specific hydrogeological data generated by the owner/operator
during the site characterization is indispensable not only to the
determination of horizontal well spacing, but to the identification of
the vertical sampling interval(s) as well.  Proper selection of the
vertical sampling interval provides the third dimension to the detection
monitoring of potential contaminant pathways to the uppermost aquifer.
Proper selection of the vertical sampling interval enables the owner/
operator to design a detection monitoring system capable of immediately
detecting a release from the hazardous waste management area with a high
level of certainty.  It is essential, therefore, that the owner/operator's
decisions regarding vertical sampling intervals are based upon site
characterization data which identify both the depth and thickness of the
stratigraphic horizon(s) most likely to serve as contaminant pathways.
There are several guidelines or criteria that the enforcement official
should follow in evaluating owner/operator decisions.  A discussion of
these guidelines follows.
     2.2.1  Depth of Wells
     The owner/operator should know from the site characterization which
stratigraphic horizons represent potential contaminant migration pathways
and should screen monitoring wells at the appropriate horizon(s) to ensure
immediate detection of a release.  It is extremely important to screen
upgradient and downgradient wells at the same stratigraphic horizon(s) to
obtain comparable ground-water quality data.  The determination of the
depth to a potential contaminant migration pathway may be made from
soil/rock cores, supplemented by geophysical and available regional
hydrogeological data.
     2.2.2  Thickness of the Vertical Sampling Interval(s)
     Determination of the appropriate thickness of the vertical sampling
interval(s) is a natural extension of the depth selection.  The owner/
operator should make the decision on the basis of site characterization
                                   2-15

-------
data.  Sources could include isopach maps of highly permeable strata,  and
stereographs of local geologic structures generated with soil/rock cores,
geophysical and regional geological data.
     In most cases, screen lengths should be no longer than ten feet.
Shorter screens promote better resolution of contaminant concentrations
than longer ones, which is a principal goal of detection monitoring.  At
sites where the vertical sampling interval is greater than ten feet, the
owner/operator should install a well cluster at each sampling location.
A well cluster is a number of wells grouped closely togetner often
screened at different stratigraphic horizons.  The greater the extent  of
the vertical sampling interval, the more wells the owner/operator should
place in a cluster.
     It is important to remember that the vertical sampling interval is
not necessarily synonymous with aquifer thickness.  In other words, the
owner/operator may select a vertical sampling interval which represents a
fraction of the thickness of the uppermost aquifer.  The selection should
be made on the basis of site characterization data.  A sufficiently
detailed site characterization may therefore reduce the need for the
owner/operator to install more speculative wells by identifying, with a
reasonable degree of certainty, the preferential flow paths from the
hazardous waste management area to the uppermost aquifer.  The owner/
operator thus tailors the selection of the vertical sampling interval to
site-specific conditions.
     There are situations where the owner/operator should have multiple
wells at a sampling  location and others where typically one well is
sufficient.  They are summarized in Table 2-2.  Generally, the presence
of immiscibles in a  thick, complex saturated zone of  the uppermost
aquifer should prompt the owner/operator to use well  clusters.  Con-
versely, single phase contaminated ground water and a thin saturated zone
within the uppermost aquifer, or isotropic hydrologic properties reduce
the need for multiple wells at each sampling location.  Where seasonal
                                   2-16

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                                TABLE 2-2

        FACTORS AFFECTING NUMER OF WELLS PER LOCATION (CLUSTERS)
One Well per Sampling Location

 No "sinkers" or "floaters"
 (immiscible liquid phases;)
  see glossary for more detail)

 Thin flow zone
 (relates to 10-foot screen
  exception)

 Homogenous uppermost aquifer;
 simple geology
More Than One Well Per Sampling

 Presence of sinkers or
 floaters

 Hetergeneous uppermost aquifer;
 complicated geology
 - multiple, interconnected
   aquifers
 - variable lithology
 - perched water table
 - discontinuous structures

 Discrete fracture zones
                                   2-17

-------
fluctuation of the water table occurs and the owner/operator intends to
sample for light phase iramiscibles floating on it, the owner/operator
should use screens long enough to always intercept the water table and
floaters instead of installing multiple wells.
     When the site characterization data indicate the presence of
different but hydraulically interconnected strata, some of the wells
should be screened with the bottom of the screens placed at the interface
between the strata.  Also, the owner/operator should have delineated
through site characterization (e.g., flow net analysis) those flow zones
in the aquifer(s) in which there is higher potential for contaminant
movement.  The owner/operator should install enough wells to ensure
continuous screening in these zones.  As above, these screens should not
be longer than ten feet in flow zones in which a higher potential for
contaminant movement exists.
     The number of wells screened at different depths that an
owner/operator should install at each sampling location increases with
site complexity.  Site factors which affect the number of wells that
should be installed at each location are described in Table 2-2.  The
following examples illustrate how enforcement officials can use the
factors discussed above to make decisions on the vertical spacing (depth)
of wells and well screens.
     Figure 2-8 illustrates a site where the owner/operator has adopted
the use of geophysical techniques and soil gas analysis in a program of
detection monitoring.  The owner/operator's landfill is situated in
unconsolidated silty sand and primarily contains organic wastes.  The
detection monitoring system in place at this  facility provides for an
integrated program of direct monitoring (e.g., wells), surface electro-
magnetic conductivity, surface resistivity, and organic vapor/soil gas
analysis.   (Appendix C provides information on geophysical  techniques and
soil/gas analysis.)  Wells are located at  300-foot intervals.  Geophysical
                                    2-18

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measurements and soil gas analysis supplement the collection of monitoring
well data.  Although the spacing between the wells has been expanded, the
collection of additional data through various complementary techniques
allows for adequate detection of leakage at this particular site.  It
should be noted, however, that the use of geophysical techniques and soil
gas analysis is not a substitute for the installation of monitoring wells.
There are, in fact, many situations where these methods cannot be used.
in any event, the applications of these methods should not result in a
drastic expansion of well spacing in a detection monitoring system.
     Figure 2-9 is a cross section of a landfill site situated on a thin
silty sand unit having a lower boundary of thick impermeable clay.  Since
the silty sand layer is the major matrix affecting ground-water flow, a
double-well cluster is necessary to ensure the unit is screened at the
water table and interface of the lowest confining unit.  The screen at
the water table must be situated and of the proper length to account for
seasonal fluctuations in the water table.
     Figure 2-10 shows the potential relationship between a landfill, its
hydrology, and well depth.  The facility is located on a thick uniform
aquifer near its discharge point.  Hydrological studies indicate an
upward flow component between the landfill and the aquifer discharge
area.  Heavy and light imraiscibles are expected from the facility.  From
this scenario, leachate is expected to move downward thereby establishing
the need for only double-well clusters to detect for light and heavy
phase materials.   (Note:  This diagram shows only one well cluster.)  The
shallow well should be screened at the water table to detect the presence
of light phase immiscibles.  The lower well should be screened where the
heavier phase materials would be expected.
     Figure  2-11 illustrates a landfill situated on silt underlain by
discretely fractured, hydraulically connected rock.  A three-well cluster
is needed to adequately monitor ground-water conditions.  The  first well
                                    2-20

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             MONITORING
               WELL
              CLUSTER
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    FIGURE  2
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                               2-21

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   WELL CLUSTER
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BACKGROUND
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                                                 10'  SCREEN LENGTH
                                                _ _ WATER TABLE
FIGURE  2-11.  WELL PLACEMENT BASED UPON CHANGES IN GEOLOGY
                             2-23

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(1A) is screened at the water table to detect light phase iramiscibles.
The 15-foot screen accounts for a five foot variation in the water
table.  The second well (IB) is screened for ten feet at the fractured
rock interface to monitor ground-water movement in the fractures.  The
third well (1C) is screened at the interface of the fractured bedrock
layer to allow for detection of contaminant movement to the first
confining unit.
     Figure 2-12 illustrates a landfill situated on silt underlain by
sand and gravel, weathered shale and solid bedrock.  The first 50 feet of
the shale is weathered.  A cluster of four wells is necessary to monitor
the ground water under this facility.  The first well (1A) monitors the
water table.  The next two wells monitor the silt (IB) sand and gravel
(1C) layers which are the major water bearing units.  The fourth well
monitors the last ten feet of the shale layer.  These last two wells are
primarily for the detection of heavy phase immiscibles.
     Figure 2-13 illustrates a landfill situated on porous sandstone
underlain by a 100-foot thick claystone unit, a coal aquifer and
bedrock.  The sandstone is not hydraulically connected to the confined
coal aquifer.  The double-well cluster (1A and IB) should include well
screens in the sandstone and in the top of the claystone.  since the
claystone has low permeability, it is not necessary to monitor the
coal-claystone interface.  The separate confined coal aquifer does not
require monitoring since slug test data from Well 2 establishes  that it
is not hydraulically connected to the upper layers.
     2.3  Placement of Upgradient (Background) Monitoring Wells
     Since the downgradient wells must be properly situated to detect
contaminant discharges into the uppermost aquifer, the upgradient wells
should be located and constructed to provide representative samples of
ground water in the same aquifer with which the downgradient samples can
be compared.
                                    2-24

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                MONITORING
                  WELL
                 CLUSTER
                   IDBC A
BACKGROUND
   WELL
  CLUSTER
                                            GROUND
                                           WATER FLOW
                                            DIRECTION
.
-------
BACKGROUND
    WELL
   CLUSTER
MONITORING
    WELL
  CLUSTER
            MONITORING
                WELL
                                                                LEGEND
                                                             j   WELL AND SCREEN


                                                            10'  SCREEN LENGTH


                                                            .7... WATER TABLE
    FIGURE 2-13. WELL DEPTH BASED UPON POSSIBLE HYDRAULIC CONNECTION
                                   2-26

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     There are three questions the enforcement official should ask as he
reviews the decisions the owner/operator has made regarding the placement
of his background monitoring wells:
     •  Has the owner/operator located background wells far enough away
        from waste management areas to prevent contamination from the
        facility?
     •  Has the owner/operator installed enough wells, screened at
        appropriate depths, to adequately account for spatial variability
        in background water quality?
     •  Has the owner/operator used well clusters at sampling locations
        so that comparisons of background data with downgradient data are
        made within the same hydrologic unit?
     The owner/operator must install background wells so that the ground-
water samples taken from these wells cannot be affected by contaminant
discharge from the facility.  Usually, this is accomplished by locating
the background wells far enough upgradient from waste management units to
avoid contamination by the facility.  For most sites, upgradient areas
which are not likely to be affected by the facility can be readily
identified from examination of water level data.  However, in some
special cases, locating the upgradient wells to avoid contamination is
complicated.
     The minimum number of wells the owner/operator may install is one.
However, a facility that uses only one well for background sampling may
not be able to account for spatial variability in water quality.  It is,
in fact, a very unusual circumstance in which only one background well
is adequate such as a facility in a completely homogeneous uppermost
aquifer.  The owner/operator who makes comparisons of background and
downgradient monitoring well results with data from only one background
well increases the risk of false indication of contamination.  In most
cases, the owner/operator should install at least four background moni-
toring wells in the uppermost aquifer to account for spatial variability
in background water quality data.
                                   2-27

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     The owner/operator should also install enough background monitoring
wells to allow for depth-discrete comparisons of water quality.  This
means simply that for downgradient wells completed in a particular
geologic formation and at a particular depth, the owner/operator should
install corresponding wells at the upgradient sampling locations so that
the data can be compared on a depth-discrete basis.  Figure 2-14
illustrates this concept.
     It is not usually acceptable for an owner/operator to install back-
ground monitoring wells that are screened over the entire thickness of
the uppermost aquifer.  Screening the entire thickness of the uppermost
aquifer will not allow the owner/operator to obtain depth-discrete water
quality data.  Instead, what the owner/operator will obtain is average
water quality data for the entire thickness of the uppermost aquifer.  In
order to obtain depth-discrete water quality data, the owner/operator
should use well screens no longer than ten feet.
     In order to establish background ground-water quality, it is
necessary to properly identify ground-water flow direction and place
wells upgradient to the waste management area.  There are several
geological and hydrological situations for which determination of the
upgradient location is often difficult; further site-specific examination
is necessary to properly locate background wells:
     1.  Waste management areas above water table mounds.
     2.  Waste management areas located above aquifers in which
         ground-water flow directions change seasonally.
     3.  Waste management areas located close to a property boundary that
         is in the upgradient direction.
     4.  Waste facilities containing significant amounts of immiscible
         contaminants with densities greater than or  less than water.
     5.  Waste management facilities located in areas where nearby
         surface water can influence ground-water levels (e.g.,  river
         floodplains).
                                   2-28

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MONITORING
   WELL
 CLUSTER
BACKGROUND
   WELL
 CLUSTER
                                                            LEGEND
                                                            WELL AND SCREEN
                                                        10'   SCREEN LENGTH
                                                       ,,.'....WATER TABLE
           FIGURE 2-14.  PLACEMENT OF BACKGROUND WELLS
                                 2-29

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6.  Waste management facilities located near production for
    intermittently-used wells.

1.  Waste management facilities located in Karst areas or faulted
    areas where fault zones may modify flow.
                               2-30

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                               CHAPTER THREE
                  MONITORING WELL DESIGN AND CONSTRUCTION

     The purpose of this chapter is to examine important aspects of RCRA
monitoring well design and construction.  Included in this chapter are
discussions on the following topics:
     •  drilling methods for installing wells (Section 3.1);
     •  monitoring well construction materials (Section 3.2);
     •  design of well intakes (Section 3.3);
     •  development of wells (Section 3.4);
     •  documentation of well construction activity (Section 3.5);
     •  specialized well design  (Section 3.6); and
     •  replacement of existing wells (Section 3.7).
     3.1  Drilling Methods
     A variety of well drilling methods are available for the purpose of
installing ground-water monitoring wells.  Of utmost importance is that
the drilling method the owner/operator uses will minimize the disturbance
of subsurface materials and will not cause contamination of the subsurface
and ground-water.  Table 3-1 illustrates the drilling methods the owner/
operator should use in installing wells.  The selection of the actual
drilling method that an owner/operator should use at a particular site
is, of course, a function of site-specific geologic conditions.  Table 3-1
illustrates how geologic conditions will influence the choice of drilling
method the owner/operator shoud use.  The following sections discuss each
drilling method and its applicability to the installation of RCRA moni-
toring wells.  It is important to note that regardless of the drilling
method the owner/operator selects, the owner/operator should steam-clean
drilling equipment before use and between borehole locations to prevent
cross contamination of wells.
                                    3-1

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                                           TABLE 3-1

                                     DRILLING METHODS FOR
                              VARIOUS TYPES OF GEOLOGIC SETTINGS
Drilling Methods
Geologic Environment
Air
Rotary
Water
Rotary
Cable
Tool
Hollow-Stem
Continuous
Auger
Solid-Stem
Continuous
Auger*
Glaciated or unconsolidated
materials less than 150 feet
deep
Glaciated or unconsolidated
materials greater than 150 feet
deep

Consolidated rock formations
less than 500 feet deep (minimal
or no fractured formations)

Consolidated rock formations
less than 500 feet deep (highly
fractured formations)

Consolidated rock formations
more than 500 feet deep (minimal
formations)

Consolidated rock formations
more than 500 feet deep (highly
fractured formations)
*Above water table.
NOTES:

1 = First choice
2 = Second choice
3 = Third choice
                                             3-2

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     3.1.1 Hollow-Stem Continuous-Flight Auger
     The hollow-stem continuous-flight auger rig is among the most
frequently employed drill rigs for the construction of monitoring wells
in unconsolidated materials.  The rigs are generally mobile, fast, and
inexpensive to operate.  No drilling fluids are used and disturbance to
the geologic materials penetrated is minimal.  However, augers can only
be used in unconsolidated rock and most rigs are limited to drilling to
approximately 150 feet.  In formations where the borehole will not stand
open, the well is constructed inside the hollow-stem augers prior to
their removal from the ground,  six-inch inside diameter hollow-stem
augers are available for this purpose.  The diameter of the well that
can be constructed with this type of drill rig is limited to four inches
or less.  The use of hoilow-stem auger drilling in heaving sand environ-
ments also presents some difficulties for the drilling crew.  However,
with care and the use of proper drilling procedures, this difficulty can
be overcome.
     3.1.2  Solid-Stem Continuous-Flight Auger
     The use of solid-stem continuous-flight auger drilling techniques
for monitoring well construction is limited to fine-grained unconsoli-
dated materials that will maintain an open borehole or in consolidated
sediments.  The method is similar to the hollow-stem continuous augers
except that the augers must be removed from the ground to allow insertion
of the well casing and screen.  This method is also limited to a depth of
up to 150 feet.  In profiles consisting of less competent materials,
solid-stem auger drilling can be utilized to limited depths; however,
caving of the borehole does present a problem making installation of the
casing difficult to impossible.  Another restriction of the solid-stem
auger is the use below the water table.  Again, maintaining the integrity
of the borehole in the saturated zone is sometimes difficult, especially
in environments of poorly consolidated sediments.  Solid-stem auger
drilling does not lend itself to in-place well construction as with the
                                    3-3

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hollow-stem auger.  Collection of soil or formation samples is impracti-
cal, and therefore, accurately portraying the subsurface profile at the
site is difficult.  Solid stem augers thus cannot be used in the boring
program for site characterization.
     3.1.3  Cable Tool
     The cable tool type of rig is relatively slow but offers many
advantages that make it the useful for monitoring well construction in
relatively shallow consolidated formations and unconsolidated formations.
The method allows for the collection of excellent formation samples and
detection of even relatively fine grained permeable zones.  The installa-
tion of a steel casing as drilling progresses also provides an excellent
temporary host for the construction of a monitoring well once the desired
depth is reached.
     Small amounts of water must be added to the hole as drilling
progresses until the water table is encountered.  The owner/operator
should only use water that cannot itself contaminate formation water.
A minimum six-inch diameter drive pipe should be used to facilitate the
placement of the well casing, screen, and gravel pack, and a minimum five
foot long seal prior to beginning the removal of the drive pipe.  The
placement of the seal in the drive pipe prior to pulling will assist in
holding the gravel pack, casing, and screen in place.  The drive pipe
should be pulled while the sealant is still fluid and capable of flowing
outward to fill the annular space vacated by the drive pipe.  The drive
pipe also should be pulled in sections and additional sealant added to
ensure that a satisfactory seal is obtained.  For the most part, cable
tool rigs have been replaced by rotary rigs in most of the United States.
Therefore, cable tool rigs may not be readily available in many regions.
     3.1.4  Air Rotary
     Rotary drilling methods operate on the principle of circulating
either a fluid or air to remove the drill cuttings and maintain an open
                                    3-4

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hole as drilling progresses.  The different types of rotary drilling are
named according to the type of fluid and the direction of fluid flow.
Air rotary drilling forces air down the drill pipe and back up the bore
hole to remove the drill cuttings.  The use of air rotary drilling
techniques is best suited for use in hard rock formations.  In soft
unconsolidated formations casing is driven to keep the formations from
caving.
     Air rotary drilling can be used for constructing monitoring wells
without affecting the quality of water from monitoring wells in hard rock
formations with minimum unconsolidated overburden.  The successful
construction of monitoring wells using this drilling technique is
dependent on the ability of the bore hole to stand open after the air
circulation ceases.  The air from the compressor on the rig should be
filtered to ensure that oil from the compressor is not introduced into
the geologic system to be monitored.  Foam or joint compounds for the
drill rods should not be used with air rotary drilling because of the
potential for introduction of contaminants into the hydrogeologic
system.  The use of air rotary drilling techniques should not be used
in highly polluted or hazardous environments.  Contaminated solids and
water that are blown out of the hole are difficult to contain and may
adversely affect the drill crew and observers.  Conversely, air rotary
drilling techniques have actually improved safety conditions where
contamination is due to volatile constituents in some instances.
     3.1.5  Water Rotary
     Water rotary drilling introduces water into the borehole by way
of the drill pipe, circulates water back up the hole and removes drill
cuttings.  Great care must be taken to ensure that water used in the
drilling process does not contain contaminants.  If the owner/operator
uses water rotary drilling to install wells,  the owner/operator should
analyze drilling water to ensure it is contaminant free.
                                    3-5

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     There are problems associated with the use of water rotary drill-
ing.  The recognition of water-bearing zones is hampered by the addition
of water into the system.  Also, in poorly consolidated sediments, the
drillers may have a problem with caving of the borehole prior to instal-
lation of the screen and casing.  In highly fractured terrains, it may
also be hard to maintain water circulation.
     3.1.6  Mud Rotary
     Mud rotary drilling techniques use various types of muds as the
medium which is introduced into the borehole.  The mud circulates back
up the hole during drilling, carrying away drill cuttings much as air and
water rotary methods.  Muds provide the additional benefit of stabilizing
the hole, especially in deep-seated highly saline formations.
     There are several types of muds available at present primarily
bentonite, barium, sulfate, and organic polymer types.  While there are
hydrogeologic conditions under which mud rotary drilling is the best
option (i.e., deep-seated highly saline formations), the enforcement
official should make certain that the mud(s) utilized affect neither
the chemistry of ground-water samples nor the operation of the well and
hence the assessment of aquifer characteristics.  For example:
     •  Bentonite muds tighten the formation around the well thereby
        compromising estimates of well recovery.  Bentonite may also
        affect local ground-water pH.
     •  Barium sulfate muds introduce barium to the ground water.  Barium
        is a RCRA extraction procedure toxicity parameter and Clean Water
        Act priority pollutant.
     •  Organic polymers and compounds provide an environment for
        bacterial growth which, in turn, reduces the reliability of
        sampling results.
     3.2  Monitoring Well Construction Materials
     The enforcement official must ensure that the owner/operator uses
well construction materials that are durable enough to resist chemical
                                    3-6

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I
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1              Figure 3-1.
and physical degradation and do not interfere with the quality of
ground-water samples.  Specific well components that are of concern
include well casings, well screens, filter packs, and annular seals.
Figure 3-1 is a diagram of a general cross section of a ground-water
monitoring well.  The following sections describe various materials the
owner/operator should use in constructing the well as illustrated in
                   3.2.1  Well Casings and Well Screen
                   A variety of construction materials have been used for  the casings
              and well screens of  including, teflon*, steel (stainless, black, galva-
              nized), PVC, polyethylene, epoxy biphenol, and polypropylene.  Many of
              these materials, however, may affect  the quality of ground-water samples
              and may not have the  long-term structural characteristics required for
              RCRA monitoring wells.  For examples, steel casing deteriorates in
              corrosive environments; PVC deteriorates when in contact with ketones,
              esters, and aromatic  hydrocarbons; polyethylene deteriorates in contact
              with aromatic and halogenated hydrocarbons; and polypropylene deteriorates
              in contact with oxidizing acids, aliphatic hydrocarbons, and aromatic
              hydrocarbons.  In addition, steel, PVC, polyethylene, and polypropylene
              may adsorb and leach  constituents which may affect the quality of
              ground-water samples.
                   In constructing  wells, the owner/operator should use teflon,
              stainless steel 316,  or other proven  chemically and physically stable
              materials for well screens and for those portions of the well casing in
              the saturated zone.   Other noninert materials such as steel, PVC, poly-
              ethylene and polypropylene may be used as well casing above the saturated
              *The use of the term "teflon" in this report by U.S. EPA is purely as a
               generic expression for polytetrafluoroethylene (PTFE) materials and in
               no way is meant to serve as an endorsement of PTFE products under the
               U.S. Trademark name of E.I. DuPont DeNemours and Company.
                                                  3-7

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                                                 STEEL PROTECTOR CAP WITH LOCKS

                                                 WELL CAP
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                                               CEMENT AND SODIUM
                                               BENTONITE MIXTURE


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zone.  Figure 3-2 illustrates the concept of such a composite well.
There are two reasons why owner/operators should use teflon or stainless
steel 316 as screens and as well casing materials.

     •  Teflon and stainless steel 316 are more highly resistant to
        corrosion from a wide variety of chemical species likely to be
        encountered in the field than other well casing materials
        currently in use, e.g., polyvinyl chloride, stainless steel 304.
        This trait is important because it indicates that wells con-
        structed of teflon or stainless steel 316 casings will retain
        their structural integrity over the long term better than those
        constructed of other materials.  Long term structural integrity,
        i.e., 30 or more years, is essential to the collection of
        unbiased ground-water samples over the active life of the
        facility.

     •  Owner/operators of facilities whose Part B or post-closure per-
        mit application has been called are required under 270.14(c)(4)
        to analyze any plume(s) for Appendix VIII constituents.  The
        remainder of facilities must monitor for Appendix VII constit-
        uents.  Both appendices include organic constituents.  Well
        construction materials should not bias the collection and
        analysis of low concentrations of these organic constituents
        by reacting with the ground-water samples.  Current research
        suggests that teflon and stainless steel 316 do not sorb or
        leach trace organics constituents to the degree that other
        materials do, e.g., organic polymers, galvanized steel.

     Plastic pipe sections must be flush threaded or have the ability to
be connected by another mechanical method which will not introduce
contaminants such as glue or solvents into the well.  All well casings
and screens should be steam cleaned prior to emplacement to ensure that
all oils, greases, and waxes have been removed.

     The owner/operator should normally use well casing with either a
two-inch or four-inch interior diameter.  Larger casing diameters,
however, may be necessary where dedicated purging or sampling equipment
is used or where the well is finished in a deep formation.  In addition,
for those wells screened at an interface between relatively tight and
porous formations and where the accumulation or bottom flow of dense
                                    3-9

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V
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                                                        GROUND SURFACE
                                        PVC OR OTHER NONINERT MATERIAL
                                        ABOVE SATURATED ZONE

                                                        POTENTIOMETRIC SURFACE
                                         INERT MATERIALS IN SATURATED
                                         ZONE (CASING AND WELL SCREEN)
                                                        CONFINING LAYER
      FIGURE 3-2. COMPOSITE WELL CONSTRUCTION
                 (INERT CONSTRUCTION MATERIALS IN SATURATED ZONE)
                                    3-10

-------
phase imraiscibles is possible, an eight to ten-inch enclosed extension of
the casing should be used to capture a sample.  The top of this sampling
cup should lie at the formation interface, and a dedicated bailer used to
draw samples.
     3.2.2  Monitoring Well Filter Pack and Annular Sealant
     The materials used to construct the filter pack should be chemically
inert (e.g., clean quartz sand, silica, or glass beads), well rounded,
and dlmensionally stable (see Section 3.3 for more detail on well intake
design).  Fabric filters should not be used as filter pack materials.
Natural gravel packs are acceptable provided that the owner/operator
conducts a sieve analysis so that the filter pack is appropriate given
well screen slot size.
     The materials used to seal the annular space must prevent the
migration of contaminants to the sampling zone from the surface or
intermediate zones and prevent cross contamination between strata.  The
materials should be chemically resistant to ensure seal integrity during
the life of the monitoring well and chemically inert so they do not
affect the quality of the ground-water samples.  Figure 3-1 illustrates
an appropriate distribution of annular sealants.  A minimum of two feet
of certified coarse grit sodium bentonite should immediately overlie the
filter pack.  Where the saturated zone extends above the well screen,
certified coarse grit sodium bentonite only should be used.  A cement and
bentonite mixture, bentonite chips/pellets, or antishrink cement mixtures
should be used as the annular sealant in the unsaturated zone above the
certified coarse grit sodium bentonite seal and below the frost line.
Above the frost line the cap should be composed of concrete blending into
a cement apron extending three feet from the outer edge of the borehole.
     The untreated sodium bentonite seal should be placed around the
casing either by dropping it directly down the borehole or, if a
hollow-stem auger is used,  putting the bentonite between the casing and
the inside of the auger stem.  Both of these methods present a potential
                                   3-11

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for bridging.  In shallow monitoring wells, a tamping device should be
used to reduce this potential.  In deeper wells, it may be necessary to
pour a small amount of formation water down the casing to wash the
bentonite down the hole.
     The cement-bentonite mixture should be prepared using formation
water and placed in the borehole using a tremie pipe.  The tremie method
ensures good sealing of the borehole from the bottom.
     The remaining annular space should be sealed with expanding cement
to provide for security and an adequate surface seals.  Locating the
interface between the cement and bentonite-cement mixture just below the
frost line serves to protect the well from damage due to frost heaving.
The cement should be placed in the borehole using the tremie method.
     Figure 3-1 illustrates an appropriate protective steel cap around
the well casing.  A one-quarter inch vent hole provides an avenue for the
escape of gas.  The protective cap guards the casing from damage and the
locking cap serves as a security device to prevent well tampering.
     3.3  Well Intake Design
     The owner/operator must design and construct the intake of the
monitoring wells so as to:  (1) allow sufficient ground-water flow to the
well for sampling; (2) minimize the passage of formation materials
(turbidity) into the well; and (3) ensure sufficient structural integrity
to prevent the collapse of the intake structure.
     For wells completed in unconsolidated materials, the intake of a
monitoring well should consist of a screen or slotted casing with
openings sized to ensure that formational material is prohibited from
passing through the well during development.  Extraneous fine-grained
material (clays and silts) that have been dislodged during drilling may
be left on the screen and the water in the well.  These fines should be
removed from  the screen and surrounding area during development.  The
owner/operator should use commercially manufactured screens or slotted
casings.  Field slotting of screens should not be allowed.
                                   3-12

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     The annular space between the face of the formation and the screen
or slotted casing should be filled to minimize passage of formation
materials into the well.  The owner/operator should therefore install a
filter pack in each monitoring well that is constructed on site.
Further, in order to ensure discrete sample horizons, the filter pack
should extent no more than two feet above the well screen as illustrated
in Figure 3-1.
     3.4  Well Development
     After the owner/operator has completed constructing monitoring
wells, natural hydraulic conductivity of the formation should be restored
and all foreign sediment removed to ensure turbid-free ground-water
samples.
     A variety of techniques are available for developing a well.  To be
effective, they require reversals or surges in flow to avoid bridging by
particles, which is common when flow is continuous in one direction.
These reversals or surges can be created by using surge blocks, bailers,
or pumps.  Formation water should be used for surging the well,  in low
yielding water-bearing formations, an outside source of water may
sometimes be introduced into the well to facilitate development.  In
these cases, this water should be chemically analyzed to ensure that it
cannot contaminate the aquifer.  The owner/operator should not use air in
the development of wells.  The owner/operator should steam clean all
equipment used to develop a well prior to its introduction into the well.
     The owner/operator must develop wells so that they are clay and
silt-free.  If, after development of the well is complete, it continues
to yield turbid ground-water samples, the owner/operator should follow
the procedure described in Figure 3-3.  The acceptance/rejection value of
five nephelometric turbidity units (N.T.U.) is based on the need to
minimize biochemical activity and possible interference with ground-water
sample quality.
                                   3-13

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                              TURBID GROUNDWATER
                                    SAMPLE
                               ANALYZE THE SAMPLE
                               WITHATURBIDMETER
                     NO
    REPURGE WELL (4.2.4)
                YES
                                                            SAMPLE IS ACCEPTABLE
REANALYZE WITH TURBIDMETER
                                     NO
                                                           ANALYZE SAMPLE USING
                                                            X-RAY DIFFRACTION
        YES
                                                  YES


SAMPLE IS
ACCEPTABLE
                                   ANALYZE
                                 FOR ORGANICS
                       YES


SAMPLE IS ACCEPTABLE:
WELL NETWORK IS USEABLE

  ARE
ORGANICS
PRESENT?
                              PRIMARILY
                                SILT&
                                CLAY?
                                                                      NO
PRIMARILY METALLIC COMPOUNDS;
    RETAIN WELL NETWORK
                                                WELL HAS BEEN IMPROPERLY
                                             CONSTRUCTED AND/OR DEVELOPED;
                                                   DO NOT USE SAMPLES
        FIGURE 3-3. DECISION CHART FOR TURBID GROUND-WATER SAMPLES
                                      3-14

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     3.5  Documentation o£ Well Design and Construction
     In the context of a compliance order, the enforcement official
should require the owner/operator to compile information on the design
and construction of wells.  Such information may include:
     •  date/time of construction;
     •  drilling method and drilling fluid used;
     •  well location (± 0.5 ft.);
     •  bore hole diameter and well casing diameter;
     •  well depth (± 0.1 ft.)
     •  drilling and lithologic logs
     •  casing materials;
     •  screen materials and design;
     •  casing and screen joint type;
     •  screen slot size/length;
     •  filter pack material/size;
     •  filter pack volume;
     •  filter pack placement method;
     •  sealant materials;
     •  sealant volume;
     •  sealant placement method;
     •  surface seal design/construction;
     •  well development procedure;
     •  type of protective well cap;
     •  ground surface elevation (+ 0.01 ft.);
     •  well cap elevation (+ 0.01 ft.).
     •  top of casing elevation (± 0.01 ft.); and
     •  detailed drawing of well (include dimensions).

     3.6  Specialized Well Designs
     There are two cases where owner/operators should use special
monitoring well designs:
                                   3-15

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     •  where the owner/operator has chosen to use dedicated pumps to
        draw ground-water samples; and
     •  where light and/or dense phase immiscibles may be present.
     If the owner/operator elects to use a dedicated system, it should
either be a teflon or stainless steel 316 bailer, or a dedicated positive
gas displacement bladder pump composed of the same two materials.  The
introduction of this pump, however, necessitates certain changes in the
well cross section depicted in Figure 3-1.  Figure 3-4 represents an
appropriate cross section of a well which utilizes a dedicated positive
gas displacement bladder pump as the sampling device/well evacuation
device.  The principal change is the addition of a two-inch diameter pump
with a Teflon outlet tubing to the well.  A four-inch interior diameter
outer well casing should easily accommodate this additional equipment.
However, should a larger pump (e.g., three inches in diameter) be
required because of greater well depth or yield, a larger outer casing
may prove necessary (six-inch interior diameter).  The pump should be
positioned midway along the screened interval, and the top of its sub-
casing should extend into the well cap as depicted in Figure 3-4.  The
subcasing may have to be braced within the outer casing to reduce
potential deformation.
     If light and dense phase immiscible layers are present, the owner/
operator must obtain discrete samples of them.  Figures 3-5 and 3-6
illustrate well cross sections which should be used for the purpose of
sampling the light phase and dense phase immiscible layers, respectively,
where  the owner/operator has chosen to use a dedicated positive gas
displacement bladder pump.  A subcasing is added to the Figure 3-1 cross
section which is sampled using a bottom filling bailer.  To capture a
sample of light phase immiscible layers, both the outer casing and
subcasing should be screened at horizons where floaters are expected.
Further, the subcasing should extend to within a couple of  inches of  the
bottom of the dense phase sampling cup to permit bailer sampling of the
                                   3-16

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                1/4" GAS VENT
         STEEL PROTECTOR CAPS WITH LOCKS

         WELL CAPS
                                                        CONCRETE CAP (EXPANDING CEMENT)

                                                        OUTLET PIPE (TEFLON TUBING)
                                                        WELL DIAMETER = 4" - 6" (OR AS
                                                        REQUIRED BY PUMPING DEVICE)
                                                        CEMENT AND SODIUM
                                                        BENTONITE MIXTURE
                                                        CERTIFIED COARSE GRIT SODIUM
                                                        BENTONITE (MINIMUM THICKNESS
                                                        2 FEET OR MORE ABOVE FILTER PACK)
                                                        FILTER PACK (2 FEET OR LESS
                                                        ABOVE SCREEN)
                                                             POTENTIOMETRIC SURFACE
                                                           SCREENED INTERVAL
                                                        POSITIVE GAS DISPLACEMENT
                                                        BLADDER PUMP
XX     XXXX     XX     «
  XX      XXXX     XX
XXX    XXX     XXX
 ZONE OF LESSER PERMEABILITY    x     X
XXX    XXXXXXX
  X     XX     XX    XXX

8" - 10" DENSE PHASE SAMPLING CUP    v  v  v
                                 A  A  A

-  BOTTOM CAP     X     X   X   x    x    *
  XXX     XXX    XX    X
                 FIGURE 3^».  MONITORING WELL CROSS-SECTION -DEDICATED
                             POSITIVE GAS PLACEMENT BLADDER PUMP
                                              3-17

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dense phase immiscible layer(s).  Where well clusters are employed, one
well in the cluster may be screened at horizons where floaters are
expected (e.g., water table, Figure 3-5), another at horizons where dense
phases are expected (e.g., aquifer/aquiclude interface, Figure 3-6), and
others within other portions of the uppermost aquifer.  Only those wells
in the cluster intended to sample for the light phase should have a
subcasing and outer casing screened to capture it, and only those wells
intended to produce samples of dense phase immiscible layers should
employ a subcasing extending into a dense phase sampling cup.  Wells in
the cluster which are not intended to generate discrete immiscible
samples do not need the subcasing.
     3.7  Evaluation of Existing Wells
     The enforcement official must decide if wells--as designed and
constructed--allow for the collection of representative ground-water
samples.  There are two situations the enforcement official may
encounter:  (1) where existing wells produce consistently turbid samples,
i.e., greater than 5 N.T.U.; (2) where the owner/operator can produce
little or no documentation on how the wells were designed and installed.
     Turbid wells or lack of information on well design and construction
may prompt the enforcement official to order the owner/operator to replace
monitoring wells.  In other, less obvious cases, the enforcement official
must use best judgment in deciding when to order an owner/operator to
replace wells.  It is likely that many owner/operators have not designed
or installed wells strictly in accordance with the guidance in this
chapter   The enforcement official must decide if the owner/operator's
wells- as built--allow the owner/ operator to collect representative
ground-water samples.  This may not be an easy judgment to make.  In
cases where it is not clear if the owner/ operator's wells can produce
representative ground-water samples, the enforcement official may con-
sider requiring the owner/operator to conduct a field demonstration.
                                   3-18

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                 1 /4" GAS VENT
             STEEL PROTECTOR CAP WITH LOCKS

             WELL CAPS
                                                          WELL DIAMETER - 4" - 6" (OR AS
                                                          REQUIRED BY PUMPING DEVICE]
                                                          BOREHOLE DIAMETER = 12'
                                                           SUBCASING = 2" (OR AS REQUIRED
                                                           BY SAMPLING DEVICE)
                                                          CONCRETE CAP (EXPANDING CEMENT)
                                                          OUTLET PIPE (TEFLON TUBING)
                                                          CEMENT AND SODIUM
                                                          BENTONITE MIXTURE
                                                          CERTIFIED COARSE GRIT SODIUM
                                                          BENTONITE (MINIMUM THICKNESS
                                                          2 FEET OR MORE ABOVE FILTER PACKI
                                                           FILTER PACK 2 FEET OR LESS
                                                           ABOVE SCREEN!
                                                              POTENTIOMETRIC SURFACE
                                                          DEDICATED POSITIVE GAS
                                                          DISPLACEMENT BLADDER PUMP
                                                          SCREENED INTERVAL
XXXXXXX    XX
   XXXXXX     XXX
XX     XXXXX     XX
   x ZONE OF LESSER PERMEABILITY x    x
x     xxxxxx     xxx
    X     XXXXX     x
   8" - 10" DENSE PHASE SAMPLING CUP X    X
xlx    x    x     xx    x     x
  - BOTTOM CAP     XXXXX
XXX     XXXXXX
             FIGURE 3-5,  MONITORING WELL CROSS-SECTION-DEDICATED POSITIVE
                         GAS DISPLACEMENT BLADDER PUMP AND SUBCASING FOR
                         DISCRETE SAMPLING OF LIGHT PHASE IMMISCIBLE LAYERS
                                              3-19

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                                                           STEEL PROTECTOR CAP WITH LOCKS

                                                           WELL CAPS
                                                        WELL DIAMETER = 4" - 6" (OR AS
                                                        REQUIRED BY PUMPING DEVICE)
                                                        BOREHOLE DIAMETER = 12"


                                                        SUBCASING = 2" (OR AS REQUIRED
                                                        BY SAMPLING DEVICE)
                                                        CONCRETE CAP (EXPANDING CEMENT)

                                                        OUTLET PIPE (TEFLON TUBING)
                                                        CEMENT AND SODIUM
                                                        SENTONITE MIXTURE
                                                            POTENTIOMETRIC SURFACE

                                                        CERTIFIED COARSE GRIT SODIUM
                                                        BENTONITE (SHOULD EXTEND TO
                                                        UPPER LIMIT OF SATURATED ZONE)
                                                        FILTER PACK (2 FEET OR LESS
                                                        ABOVE SCREEN)
                                                     KSCREENED INTERVAL
                                                     I
                                                        DEDICATED POSITIVE GAS
                                                        DISPLACEMENT BLADDER PUMP
  XXXXX     XX     X
XXX    XXXXX     X
  XXX    XXXXX
X ZONE OF LESSER PERMEABILITY XXX
  XXXX     XXXX
XXXXX
8" - 10" DENSE SAMPLING CUP
                           x    x     i
                             X    X
X     XXXX     X     XX
BOTTOM CAP   XXXXX
X	XXXX	XXX
          FIGURE 3-6.  MONITORING WELL CROSS-SECTION - DEDICATED POSITIVE GAS
                      DISPLACEMENT BLADDER PUMP AND SUBCASING FOR DISCRETE
                      SAMPLING OF DENSE PHASE IMMISCIBLE LAYERS
                                            3-20

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This demonstration would involve the installation of new well(s) near
existing wells.  The owner/operator would sample for and analyze the same
set of parameters in both wells.  If parameter values are equivalent, the
enforcement official should assume the owner/operator's existing wells
are producing representative samples.
                                   3-21

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                               CHAPTER FOUR
                           SAMPLING AND ANALYSIS

     Section 265.92 requires the owner/operator to prepare and implement
a written ground-water sampling and analysis (S&A) plan.  This plan must
include procedures and techniques for sample collection, sample
preservation and shipment, analytical procedures and chain of custody
control.  The owner/operator's S&A plan is an important document.  It
allows the enforcement official to thoroughly review how the
owner/operator has structured the S&A program.  Also, comparison of the
written plan to field activities will allow the enforcement official to
ensure the owner/operator is, in fact, properly collecting and analyzing
ground-water samples.  The purpose of this chapter is to describe
important elements of written S&A plans and to discuss the level of
detail that owner/operators should include in their plans.
     EPA has observed a number of problems in the way in which owner/
operators prepare their S&A plans or implement their S&A programs.  Some
of the more common problems are listed below.
     •  Owner/operators have not prepared S&A plans or do not keep plans
        on site.
     •  Plans contain very little information or do not adequately
        describe the S&A program the owner/operator is employing at his
        facility.
     •  Field sampling personnel are not following the written plan or
        are not even aware that it exists.
     •  Improper evacuation techniques are used particularly in regards
        to the identification and collection of immiscible contaminants.
     •  Sampling equipment is used that may alter chemical constituents
        in ground water.
     •  Sampling techniques are used that may alter chemical composition
        of samples particularly in regard to stripping of volatile
        organic compounds in samples.
                                    4-1

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     •  Facility personnel are not using blanks, standards, and spiked
        samples to correct analytical results for changes in sample
        quality after collection.
     •  Field personnel do not properly clean nondedicated sampling
        equipment after use.
     •  Field personnel are placing sampling equipment (rope, bailer,
        tubing) on the ground where it can become contaminated prior to
        use.
     •  Field personnel do not document their field activities adequately
        (e.g., keep sampling logs).
     •  Field personnel are not following proper chain-of-custody
        procedures.
     •  Little attention is paid to data reporting errors or anamolies.
     •  Facility personnel have not reviewed the QA/QC procedures being
        used by the laboratory that is analyzing their ground-water
        samples.
     This chapter describes important elements in S&A plans (Section 4.1),
and then discusses the level of detail the owner/operator should include
in his plan in regard to each S&A element (Sections 4.2 through 4.6).
Furthermore, this chapter describes important aspects of evaluating the
field implementation of S&A plans (Sections 4.2 through 4.6).  Section 4.7
describes how enforcement officials may examine ground-water data to
identify evidence of problems in the way owner/operators acquire,
process, and evaluate data.
     4.1  Elements of Sampling and Analysis Plans
     The owner/operator's S&A plan should, at minimum, address a number
of elements.  Specifically, the S&A plan should include information on:
     •  Sample collection (Section 4.2);
     •  Sample preservation and handling (Section 4.3);
     •  Chain of custody control (Section 4.4);
     •  Analytical procedures (Section 4.5); and
     •  Field and laboratory quality assurance/quality control
        (Section 4.6).

                                    4-2

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     4.2  Sample Collection
     4.2.1  Measurement of Static Water Level Elevation
     The owner/operator's sampling and analysis plan should include
provisions for measurement of static water level elevations in each
well.  Collection of water level elevation on a continuing basis is
important to determine if horizontal and vertical flow gradients have
changed since initial site characterization.  A change in hydrologic
conditions may necessitate modification to the design of the owner/
operator's ground-water monitoring system.  The S&A plan should specify
the device to be used for water level measurements as well as the
procedure for measuring water levels.
     The owner/operator's field measurements should include depth to
standing water and total depth of the well to the bottom of the intake
screen structure.  The measurements should be taken to 0.1 foot.  Each
well should have a reference point from which its water level measurement
is taken.  The reference point should be established by a licensed
surveyor and is typically located at the top of the well casing with
locking cap off.  The reference point should be established in relation
to mean sea level and the survey should also note the well location
coordinates.  The device which is used to detect the water level surface
must be sufficiently sensitive so that a measurement to +0.1 foot can be
obtained reliably.  A steel tape will usually suffice, however, it is
recommended that an electronic device (e.g., M-Scope or sounder) be used
to measure depth to the surface of the ground water or light phase
immiscibles.
     4.2.2  Detection of Immiscible Layers
     The owner/operator's S&A plan should include provisions for
detecting immiscible contaminants, i.e., "floaters" and "sinkers" if the
owner/operator manages wastes of this type at his facility.  "Floaters"
are those relatively insoluble organic liquids which are less dense than
                                    4-3

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water that spread across the water table surface,  "sinkers" are those
relatively insoluble organic liquids which are more dense than water and
tend to migrate vertically through the sand and gravel aquifers to the
underlying aquitard.  The detection of these immiscible layers requires
specialized equipment which must be used before the well is evacuated for
conventional sampling.  The S&A plan should specify the device to be used
to detect "floaters" and "sinkers" as well as the procedures to be used
for detecting and sampling these contaminants.
     Owner/operators should follow the procedures below for detecting the
presence of light and/or dense phase immiscible organic layers should be
undertaken before the well is evacuated for conventional sampling:
     1.  Remove the locking and protective caps.
     2.  Sample the air in the well head for organic vapors using either
         an HMD or OVA, and record measurements.
     3.  Determine the static liquid level using a manometer or
         acoustical sounder, and record the depth.
     4.  Lower an interface probe into the well to determine the exitence
         of any immiscible layer(s), light and/or dense.
     The air above the well head should be sampled in order to determine
the potential for fire, explosion, and/or toxic effects on workers.  This
test also serves as a first indication of the presence of immiscible
organics.  A manometer or acoustical sounder may provide an accurate
reading of the depth to the surface of the liquid in the well, but
neither are capable of differentiating between the water table and the
surface of a floater.  Nonetheless, it is very useful to determine that
depth first to guide the lowering of the interface probe.  The interface
probe serves two related purposes.  First, as it is lowered into the
well, the probe registers when it is exposed to an organic liquid and
thus identifies the presence of immiscible layers.  Careful recording of
the depths of the air/floater and floater/water interfaces establishes a
measurement of the thickness of the light phase immiscible layer.
                                    4-4

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Secondly, as the probe is lowered through the light phase immiscible
layer, it indicates the depth to the static water level.  The presence of
floaters precludes the exclusive use of sounders to make a determination
of static water level.  Dense phase immiscibles layers are detected by
lowering the device to the bottom of the well where again the interface
probe registers the presence of organic liquids.
     Sampling of immiscible fractions should precede well evacuation
procedures.  A bottom filling bailer should be lowered to the levels at
which the light and dense phase immiscibles are found and a sample
taken.  Care should be taken to gently lower the bailer to avoid, as much
as possible, disturbing the interface between the organic liquid and
water.
     4.2.3  Well Evacuation
     The water standing in a well prior to sampling may not be
representative of in-situ ground-water quality.  Therefore, the
owner/operator should remove the standing water in the well so that water
which is representative of the formation can replace the standing water.
The owner/operator's S&A plan should include detailed, step-by-step
procedures for evacuating wells.  The equipment the owner/operator plans
to use to evacuate wells should also be described.
     The owner/operator's evacuation procedure should ensure that all
stagnant water is replaced by fresh formation water upon completion of
the process.  The owner/operator should draw the water down from above
the screen in the uppermost part of the water column to ensure fresh
water from the screen will move upward.
     The procedure the owner/operator should use for well evacuation
depends on the yield of the well.  When evacuating low yield wells, the
owner/operator should evacuate wells to dryness once.  As soon as the
well recovers, the first samples the owner/operator should remove are the
ones to be tested for volatilization sensitive parameters (e.g., total
                                    4-5

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organic halogens) and/or pH, oxidation reduction.  Whenever full recovery
exceeds three hours, the owner/operator should extract the remaining
samples in order of their volatility as soon as sufficient volume is
available for a sample for each parameter.  Parameters that are not pH
sensitive or subject to loss through volatilization, (such as nonvolatile
or nonreactive organics) should be drawn last.  At no time should an
owner/operator pump a well to dryness if the recharge rate causes the
formation water to vigorously cascade down the intake screen and
accelerate the loss of volatiles.  If this is anticipated to be a
problem, the owner/operator should purge three casing volumes from the
well at a rate which does not cause to recharge water to be excessively
agitated.  For higher yielding wells, the owner/operator should evacuate
three casing volumes prior to sampling.
     In order to minimize the introduction of contamination into the well
positive gas displacement teflon bladder pumps are recommended for
purging wells.  Teflon or stainless steel bailers are also recommended
purging equipment.  Where these devices cannot be used,  peristalitic
pumps, gas-lift pumps, centrifugal pumps, and venturi pumps may be used.
Some of these pumps produce volatilization and high pressure
differentials, causing variability in the analysis of pH, specific
conductance, metals, and volatile organic samples.  They are, however,
acceptable for purging the wells if sufficient time is allowed to let the
water stabilize prior to sampling.
     When purging equipment must be reused, it should be decontaminated
with a water wash and a deionized distilled water rinse.  Purging
equipment which becomes heavily contaminated should be cleaned with a
nonphosphate detergent wash followed by rinsing with hexane and deionized
distilled water.  Clean gloves should be worn by the sampling personnel.
A clean plastic sheet should be placed adjacent to or around the well in
order to prevent surface soils from coming in contact with the purging
equipment and lines, which in turn could introduce contaminants to the
well.
                                    4-6

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     4.2.4  Sample Withdrawal
     The technique used to withdraw a ground-water sample from a well
should be selected based on a consideration of the parameters which will
be analyzed in the sample.  To ensure the ground-water sample is
representative of the formation, it is important to avoid physically
altering or chemically contaminating the sample during the withdrawal
process.  In order to minimize the possibility of sample contamination,
the owner/operator should:
     1.  Use only Teflon* or stainless steel (316) sampling devices,
         and
     2.  Use dedicated samplers for each well.  (If a dedicated sampler
         is not available for each well, the owner/operator should
         thoroughly clean the sampler between sampling events and the
         owner/operator should take blanks and analyze them to ensure
         cross-contamination has not occurred.)
     The owner/operator's S&A plan should specify in detail the devices
the owner/operator will use for sample withdrawal.  The plan should state
that devices are either dedicated to a specific well or are capable of
being fully disassembled and cleaned between sampling events.  Procedures
for cleaning the sampling equipment should be included in the plan.  Any
special sampling procedures that the owner/operator must use to obtain
samples for a particular constituent (e.g., TOX or TOC) should also be
described in the plan.
     When used properly, the following are acceptable sampling devices
for all parameters:
     •  Bottom valve bailers (Teflon or stainless steel 316); and
     •  Positive gas displacement bladder pump
Sampling equipment should be constructed of inert material.  Equipment
with neoprene fittings, PVC bailers, tygon tubing, silicon rubber
bladders, neoprene impellers, polyethylene, and vitron are not acceptable.
*Tradename for polyperfluoroethylene
                                    4-7

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If the owner/operator is using bailers, "Teflon"-coated wire, single
strand stainless steel wire, or monofilament should be used to raise and
lower the bailer.  Braided cables, polyethylene or nylon cords should not
be used because it may not be possible to thoroughly decontaminate these
materials prior to sampling.
     The owner/operator may use Teflon or stainless steel 316 bailers for
any depth well.  A single positive gas displacement bladder pump or
several pumps connected in series may be used for wells 150 to 400 feet
deep.  For wells greater than 400 feet deep, the owner/operator should
use bailers with a manual or powered winch to raise and lower the device
in the well.
     While in the field, the enforcement official should observe the
owner/operator's sampling technique to ensure that the owner/operator
satisfies the following:
     •  Positive gas displacement bladder pumps should be operated in a
        continuous manner so that they do not produce pulsating samples
        that are aerated in the return tube or upon discharge;
     •  Check valves should be designed and inspected to assure that
        fouling problems do not reduce delivery capabilities or result in
        aeration of the sample;
     •  Sampling equipment (e.g., especially bailers) should never be
        dropped into the well because this will cause degassing of the
        water upon impact;
     •  The bailer's contents should be transferred to a sample container
        in a way that will minimize agitation and aeration; and
     •  Clean sampling equipment should not be placed directly on the
        ground or other contaminated surfaces prior to insertion into the
        well.
     When dedicated equipment is not used for sampling (or well
evacuation), the owner/operator's sampling plan should include procedures
for disassembly and cleaning of equipment before each use.  If the
constituents of interest are inorganic, the first rinse should be a
                                    4-8

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               dilute  (0.1  N)  hydrochloric  acid  or  nitric  acid  and  the second  rinse
               should  be  distilled  water  or deionized  water.  Dilute  hydrochloric  acid
               is  generally preferred  to  nitric  acid when  cleaning  stainless steel
|               because nitric  acid  may oxidize stainless steel.   When organics are the
1               constituents of concern, the owner/operator should wash equipment with a
i
,               nonphosphate detergent  and rinse  with tap water,  distilled water,
1               acetone, and finally pesticide-quality  hexane, in that order.   The
               sampling equipment should  be thoroughly dried  before use to ensure  that
               the residual cleaning agents (e.g.,  acetone, HC1) are  not  carried over to
i               the sample.
                    When  collecting samples using a positive  gas displacement  bladder
               pump for volatile analysis,  pumping  rates should not exceed
               100 milliliters/minute.  Higher rates can increase the loss of  volatile
               constituents and can cause fluctuation  in pH and pH  sensitive analytes.
               Once the portions of the sample reserved for the analysis  of volatile
               components has  been  collected,  the owner/operator may  use  higher pumping
               rates particularly if a large sample volume must be  collected.
                    4.2.5  In-Situ  or  Field Analyses
                    Several parameters are  physically  or chemically unstable and must be
               tested  either in the borehole using  a probe (in-situ)  or immediately
               after collection using  a field  test  kit.  Examples of  several unstable
               parameters include pH,  redox potential,  chlorine, dissolved oxygen,  and
               temperature.  Although  specific conductivity (analogous to electrical
               resistance)  is  relatively  stable,  it is recommended  that this
               characteristic  be determined in the  field.   Most conductivity instruments
               require temperature  compensation,  therefore temperatures of the sample
               should  be  measured at the  time conductivity is determined.   If  the
               owner/operator  uses  probes (pH electrode, specific ion electrode,
               thermistor)  to  measure  any of the above parameters,  it is  important  that
               this is done after well  evacuation and  after any samples for chemical
                                                  4-9

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analysis have been collected so that the probe(s) do not contaminate the
sample designated for laboratory analysis.  Similarly, if the unstable
parameters are to be determined in a sample withdrawn from a well, the
owner/operator should  split the sample into at least two separate
portions, one for field testing and the other for laboratory analysis.
Monitoring probes should not be placed in containers containing
ground-water for laboratory analysis.
     The owner/operator should complete the calibration of any in-situ
monitoring equipment or field test probes and kits before each use
according to the manufacturers specifications and consistent with sw-846.
     4.3  Sample Preservation and Handling
     Many of the constituents and parameters that are included in
ground-water monitoring programs are not stable, and therefore, sample
preservation is required.  Test Methods for Evaluating Solid Waste -
Physical Chemical Methods (sw-846, Section 1.4.6.2.3) has a discussion
for each analytical technique on the choice sample preservation
procedures.  In addition, SW-846 (Section 1.2.2) specifies the sample
containers that the owner/operator should use for each constituent or
common set of parameters.  The owner/operator should identify in the S&A
plan which preservation methods and sample containers will be employed.
Each sampling and analysis plan should also detail all procedures and
techniques for transferring the samples to either a field or off-site
laboratory.
     Improper sample handling may lead to loss of contaminant
constituents in the sample.  Samples should be transferred in the field
from the sampling equipment directly into to the container that has been
specifically prepared for that given parameter or set of compatible
parameters.  It is not an acceptable practice for samples to be
composited in a common container in the field and then split in the
laboratory, nor poured first into a wide mouth container then transferred
                                   4-10

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into smaller jars.  In regard to volatile organics, the S&A plan should
specify how the samples will be transferred from the sample collection
device to the sample container to reduce loss through volatilization.
When using a bailer to collect samples for the analysis of volatiles, the
sample may be transferred to a beaker which will facilitate the filling
of a volatile organics analysis (VGA) vial.  The water should be poured
from the beaker to the VOA vial so that the vial overflows and no bubbles
or headspace is left in the vial.
     4.3.1  Sample Containers
     The owner/operator's S&A plan should identify the type of sample
containers to be used to collect samples as well as procedures the
owner/operator will use to ensure that sample containers are free of
contaminants prior to use.
     When metals are the analytes of interest, polyethylene containers
with polypropylene caps should be used.  When organics are the analytes
of interest, glass bottles with Teflon-lined caps should be used.  Glass
bottles may be used to store samples for metals analysis providing the
caps are Teflon-lined and the appropriate preservative has been used.
The plan should refer to the specific analytical method (in SW-846,
Section 1.2.2) which designates an acceptable container.
     Containers should be cleaned to suit the type of analysis the sample
will be subjected to.  When samples are to be analyzed for metals
(SW-846, Method 6010), the sample containers as well as the laboratory
glassware should be thoroughly washed with nonphosphate detergent and tap
water, and rinsed with (1:1) nitric acid, tap water, (1:1) hydrochloric
acid, tap water, and finally Type II water, in that order.  Chromic acid
may be useful to remove organic deposits from glassware; however, the
analyst should be cautioned that the glassware must be thoroughly rinsed
with water to remove the last traces of chromium.  The use of chromic
acid can cause a contamination problem for the determination of chromium
                                   4-11

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if the glassware is not rinsed properly.  If it can be documented through
an active analytical quality control program using spiked samples and
reagent blanks that certain steps in the cleaning procedure are not
required for routine samples, those steps may be eliminated from the
procedure.
     Similarly, an EPA-approved procedure (SW-846, Method 8080) is
available for cleaning containers used to store samples for organics
analysis.  The sampling container should be emptied of any residual
materials followed by washing with a nonphosphate detergent in hot
water.  Rinse with tap water, distilled water, acetone, and finally
pesticide-quality hexane.  Heavily contaminated glassware may require
treatment in a muffle furnace at 400°C for 15 to 30 minutes.  Glassware
should be sealed/stored in a clean environment immediately after drying
or cooling to prevent any accumulation of dust or other contaminants.
Store inverted or capped with aluminum foil.
     The cleanliness of a batch of precleaned bottles should be verified
by the use of a trip blank.  Each time a group of bottles is prepared for
use in the field, one bottle of each type (e.g., glass, Teflon,
polyethylene) should be selected from the batch and filled with deionized
water.  The bottles filled with the blank should be transported to the
sampling location and returned to the laboratory in a manner identical to
the handling procedure used for the samples.  Trip blanks should be
subjected to the same analysis as the ground water.  Any contaminants
found in the trip blanks could be attributed to (1) interaction between
the sample and the container, (2) contaminated deionized water, or (3) a
handling procedure which alters the sample.  The concentration levels of
any contaminants found in the trip blank should not be used to correct
the ground-water data.  The contaminant levels should be noted and if the
levels are significant compared to the field sample results, the owner/
operator should resample the ground water.
                                   4-12

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     4.3.2  Sample Preservation
     The owner/operator's S&A plan should identify sample preservation
methods that the owner/operator plans to use.  Methods of sample
preservation are relatively limited and are generally intended to
(1) retard biological action, (2) retard hydrolysis, and (3) reduce
absorption effects.  Preservation methods are generally limited to pH,
control, chemical addition, refrigeration, and freezing.  The
owner/operator should refer to the specific preservation method in
SW-846, Section 1.4.6.2.3 that will be used for the constituent in the
sample.  A summary of adequate sample containers and sample preservation
measures is presented in Table 4-1.
     4.3.3  Special Handling Considerations
     Organics
     Samples requiring analysis for organics should not be filtered.
Samples should not be transferred from one container to another because
losses of organic material onto the walls of the container may occur.
Total organic halogens (TOX) and total organic carbon (TOC) samples
should be handled and analyzed as materials containing volatile
organics.  No headspace should exist in the sample containers to minimize
the possibility of volatilization of organics.  Field logs and laboratory
analysis reports should note the headspace in the sample container(s) at
the time of receipt by the laboratory as well as at the time the sample
was first transferred to the sample container at the wellhead.
     Metals
     Metals which migrate through the unsaturated (vadose) and saturated
zones and arrive at a ground-water monitoring well are typically in a
dissolved state.  Particles (e.g., silt, clay) which may be present in
the well even after well evacuation procedures may absorb or adsorb
various metals species to effectively lower the dissolved metal content
                                   4-13

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                                           TABLE 4-1

                 SAMPLING AND PRESERVATION PROCEDURES FOR DETECTION MONITORING3
Parameter

PH
Specific conductance
TOC

TOX


Chloride
Iron
Manganese
Sodium
Phenols
Sulfate

Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Selenium
Silver
Minimum Volume
Recommended Maximum Required for
Container^ Preservative Holding Time Analysis
Indicators of Ground-Water Contamination0
T, P, G Field determined 2 hours
T, P, G f eld determined None
G, Teflon-lined Cool 4°C, HC1 to 28 days
cap pH <2
G, amber, Teflon- Cool 4°C, add 1 ml of 7 days
lined cap 1. 1M sodium sulfite
Ground-Water Quality Characteristics
T, P, G 4°C 28 days
T, P Field Acidified*1 6 months
to pH <2 with HNC^

G 4°C/H0SO, to pH <2 28 days
i 4
T, P, G Cool, 4°C 28 days
EPA Interim Drinking Water Characteristics
T, P Total Metals 6 months
Field acidified to
pH <2 with HN03
6 months
Dissolved Metals
1. Field filtration
(0.45 micron)
2. Acidify to pH <2

25 ml
100 ml
4 x 15 ml

4 x 15 ml


50ml
200 ml


500ml
50 ml

1,000 ml


1,000 ml




Fluoride
Nitrate
T, P


T, P, G
   with HN03

Field acidified to
 pH <2 with HN03
                                           (Continued)
28 days


48 hours
300 ml


1 ,000 ml
                                              4-14

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                                      TABLE 4-1  (Continued)

                  SAMPLING AND PRESERVATION PROCEDURES FOR DETECTION MONITORING


Parameter
Endrin
Lindane
Hethoxychlor
Toxaphene
2,4 0
2,4,5 TP Silvex
Radium
Gross Alpha
Gross Beta
Col i form bacteria

Recommended
Container1* Preservative
T, G Field acidified to
pH <2 with HN03




P, G Field acidified to
pH <2 with HN03

PP, G (sterilized) Cool, 4°C

Maxinun
Holding Time
24 hours





6 months


6 hours
Minimum Volume
Required for
Analysis
1,000 ml





1 gallon


200 ml
Cyanide


Oil and Grease
Other Ground-Water Characteristics of Interest

P, G                Cool, 4°C, NaOH to       14 days
G only
Hazardous constituents   G only
 (§261, Appendix VIII)
Cool, 4°C, NaOH to       14 days         500 ml
 pH >12

Cool, 4°C H2S04 to       28 days         100 ml
 pH <2

Cool, °4C                7 days          1 gallonf
References:  Test Methods for Evaluating Solid Waste - Physical/Chemical Methods. SW-846
              (2nd edition, 1982).
              Methods for Chemical Analysis of Hater and Wastes. EPA-600/4-79-020.
              Standard Methods for the Examination of Hater and Wastewater. 16th edition (1985).

''Container Types:
     P = Plastic (polyethylene)
     G = Glass
     T = Teflon
    PP = Polypropylene

cBased on the requirements for detection monitoring (§265.93), the owner/operator must collect
 a sufficient volume of ground water to allow for the analysis of four separate replicates.

                                             (Continued)
                                              4-15

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                                       TABLE 4-1  (Continued)

                   SAMPLING AND PRESERVATION PROCEDURES FOR DETECTION MONITORING
dln the event that HN03 cannot be used because of shipping restrictions,  the sample should be
 refrigerated to 4°C, shipped immediately,  and acidified on receipt at the laboratory.
     samples from nonchlorinated drinking water supplies concentrated ^$04 should be added
 to lower sample pH to less than 2.   The sample should be analyzed before 14 days.

fy)r as required by the procedures (SW-846) for the specific hazardous constituents being
 assessed.
                                              4-16

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in the well water.  Ground-water samples on which metals analysis will be
conducted should be split into two portions.  One portion should be
filtered through a 0.45 micron filter (glass fiber or membrane),
transferred to a bottle, preserved with nitric acid to a pH less than 2
(Table 4-1) and analyzed for dissolved metals.  The remaining portion
should be transferred to a bottle, preserved with nitric acid and
analyzed for total metals.  Any difference in concentration between the
total and dissolved fractions may be attributed to the original metal
content of the particles and any migration of dissolved metals to the
particles.
     Blanks
     Various types of blanks should be used to verify that the sample
collection and handling process has not affected the quality of the field
samples (see Section 4.6 for more information on field and laboratory
QA/QC programs).  The owner/operator should prepare each of the following
field blanks and analyze them for all of the required monitoring
parameters:
     Trip Blank - Fill one of each type of sample bottles with deionized
     water, transport to the site, handle like a sample, and return to
     the laboratory for analysis.  One trip blank per sampling event is
     recommended.
     Equipment Blank - To ensure the sampling device has been effectively
     cleaned (in the laboratory or field), fill the device with deionized
     water or pump deionized water through the device, transfer to sample
     bottle(s) and return to the laboratory for analysis.  One equipment
     blank each day ground-water monitoring wells are sampled is
     recommended.
     The results of the analysis of the blanks should not be used to
correct the ground-water data.  If contaminants are found in the blanks,
the source of the contamination should be identified and corrective
action, including resampling, should be initiated.  Other quality control
samples (e.g., standards, spikes, performance evaluation samples) should
be prepared and analyzed as part of the laboratory operation (see
                                   4-17

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Section 4.6.1).  The owner/operator's S&A plan should include provisions

for the use of trip blanks and equipment blanks as well as other QA/QC

activities.

     4.4  Chain of Custody

     The owner/operator must describe a chain-of-custody program in the
S&A plan.  An adequate chain-of-custody program will allow for the

tracing of possession and handling of individual samples from the time of
field collection through laboratory analysis.  An owner/operator's chain-
of-custody program should include:

     •  Sample labels which prevent misidentification of samples;

     •  Sample seals to preserve the integrity of the sample from the
        time it is collected until it is opened in the laboratory;

     *  Field logbook to record information about each sample collection
        during the ground-water monitoring program;

     •  Chain-of-custody record to establish the documentation necessary
        to trace sample possession from the time of collection to
        analysis;

     •  Sample analysis request sheets which serve as official
        communication to the laboratory of the particular analysis(es)
        required for each sample and provide further evidence that the
        chain of custody is complete; and

     •  Laboratory logbook which is maintained at the laboratory and
        records all pertinent information about the sample.

     4.4.1  Sample Labels

     To prevent misidentification of samples, the owner/operator should

affix legible labels to each sample container.  The labels should be
sufficiently durable to remain legible even when wet and should contain
the following type of information:

        Sample identification number
        Name of collector
        Date and time of collection
        Place of collection
        Parameter(s) requested (if space permits)
                                   4-18

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     4.4.2  Sample Seal

     In cases where samples may leave the owner/operator's immediate
control, such as shipment to a laboratory by a common carrier (e.g., air
freight), a seal should be provided on the shipping container or

individual sample bottles to ensure the samples have not been disturbed
during transportation.

     4.4.3  Field Logbook

     An owner/operator or the individual designated to perform

ground-water monitoring operation should keep an up-to-date field logbook

which documents the following:

        Identification of well
        Well depth
        Static water level depth and measurement technique
        Presence of immiscible layers and detection method
        Well yield - high or low
        Collection method for immiscible layers and sample identification
        numbers
        Well evacuation procedure/equipment
        Sample withdrawal procedure/equipment
        Date and time of collection
        Well sampling sequence
        Types of sample containers used and sample identification numbers
        Preservative(s) used
        Parameters requested for analysis
        Field analysis data and method(s)
        Sample distribution and transporter
        Field observations on sampling event
        Name of collector

     4.4.4  Chain-of-Custody Record
     To establish the documentation necessary to trace sample possession
from time of collection, a chain-of-custody record should be filled out
and accompany every sample.  The record should contain the following type
of information:

     •  Sample number
     •  Signature of collector
     •  Date and time of collection
     •  Sample type (e.g., ground water, immiscible layer)
                                   4-19

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        Identification of well
        Number of containers
        Parameters requested for analysis
        Signature of person(s) involved in the chain of possession
        Inclusive dates of possession
     4.4.5  Sample Analysis Request Sheet
     This document should accompany the sample(s) on delivery to the
laboratory and clearly identify which sample containers have been
designated (e.g., use of preservatives) for each requested parameter.
The record should include the following type of information:
     •  Name of person receiving the sample
     •  Laboratory sample number (if different than field number)
     •  Date of sample receipt
     •  Analyses to be performed
     4.4.6  Laboratory Logbook
     Once the sample has been received in the laboratory, the sample
custodian and/or laboratory personnel should clearly document the
processing steps which are applied to the sample.  All sample preparation
techniques (e.g., extraction) and instrumental methods must be identified
in the logbook.  Experimental conditions such as the use of specific
reagents (e.g., solvents, acids), temperatures, reaction times and
instrument settings should be noted.  The results of the analysis of all
quality control samples should be identified specific to each batch of
ground-water samples analyzed.  The laboratory logbook should include the
time, date, and name of the person who performed each processing step.
     4.5  Analytical Procedures
     The owner/operator's S&A plan should describe in detail the
analytical procedures that will be used to determine the concentrations
of constituents or parameters of interest.  These procedures should
include suitable analytical methods as well as proper quality assurance
and quality control protocols.  The required precision, accuracy,
                                   4-20

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detection limits and percent recovery (if applicable) specifications
should be clearly identified in the plan.
     The S&A plan should identify one method that will be used for each
specific parameter or constituent.  Generally, the plan should specify a
method in SW-846 or an EPA-approved method and clearly indicate if there
are going to be any deviations from the stated method.
     Records of ground-water analyses should include the methods used,
extraction date and date of actual analysis.  Data from samples which are
not analyzed within recommended holding times should be considered
invalid.  Any deviation from an EPA-approved method (SW-846) should be
adequately tested to ensure that the quality of the results meets the
performance specifications (e.g., detection limit, sensitivity,
precision, accuracy) of the reference method.
     4.6  Field and Laboratory Quality Assurance/Quality Control
     One of the fundamental responsibilities of the owner/operator is the
establishment of continuing programs to ensure the reliability and
validity of field and analytical laboratory data gathered as part of the
overall ground-water monitoring program.
     The owner/operator's S&A plan must explicitly describe the QA/QC
program that will be used in the field and  laboratory.  Many
owner/operators use commercial laboratories to conduct analyses of
ground-water samples.  In these cases, it is the owner/operator's
responsibility to ensure that his laboratory of choice is exercising a
proper QA/QC program.  The QA/QC program described in the
owner/operator's S&A plan must be used by the laboratory analyzing
samples for the owner/operator.
     4.6.1  Field QA/QC Program
     The owner/operator's S&A plan should provide for the routine
collection and analysis of two types of QC  blanks:  trip blanks and
                                   4-21

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equipment blanks.  Trip blanks are used to determine if contamination is
introduced from the sample containers (see Section 4.3.3).  Equipment
blanks are used to determine if contamination is introduced by the sample
collection equipment (see Section 4.3.3).
     All field equipment the owner/operator will use should be calibrated
prior to field use and recalibrated periodically.  The owner/operator's
S&A plan should describe a program for ensuring proper calibration of
field equipment.  Other QA/QC practices such as sampling equipment
decontamination procedures and chain of custody procedures should also be
described in the owner/operator's S&A plan.
     4.6.2  Laboratory QA/QC Program
     The owner/operator's S&A plan should provide for the use of
standards, laboratory blanks, duplicates, and spiked samples for
calibration and identification of potential matrix interferences.  The
owner/operator should use adequate statistical procedures (e.g., QC
charts) to mon1 or and document performance and implement an effective
program to resolve testing problems (e.g., instrument maintenance,
operator training).  Data from QC samples (e.g., blanks, spiked samples)
should be used as a measure of performance or as an indicator of
potential sources of cross-contamination but should not be used to alter
or correct analytical data.  These data should be submitted to the Agency
with the ground-water monitoring sample results.
     4.7  Evaluation of the Quality of Ground-Water Data
     A ground-water sampling and analysis program produces a variety of
geohydrological, geophysical, and ground-water chemical constituent
(GWCC) data.  This section pertains primarily to the evaluation of GWCC
data because these data are specifically required by the regulations, are
evaluated in the statistical tests, provide the fundamental evidence used
to determine whether the facility is contaminating the ground water, and
                                   4-22

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are used to determine the extent of plume migration during assessment
monitoring.  Also, details regarding how to obtain and identify quality
geohydrological and geophysical data have been discussed in Chapters One
through Three.  The GWCC data may be initially presented by the
laboratory on reporting sheets; these data then must be compiled and then
analyzed by the owner/operator prior to submission to the state or EPA in
order to evaluate the degree of ground-water contamination.
     It is essential for owner/operator to make sure that during chemical
analysis, compilation, laboratory reporting, computer automation, and
report preparation that data are generated and processed to avoid
mistakes and that data are complete and fully documented.  Data must be
accurately reported to have accurate analyses and valid results.  If data
errors do occur, statistical analyses cannot discover, correct, or
ameliorate the errors.
     The following discussion considers aspects of data quality that may
indicate to the enforcement officer that the data acquisition,
processing, and evaluation were executed poorly or incorrectly.
     The specific areas that are addressed include:
     •  Reporting of low and zero concentration values;
     •  Number of significant digits;
     •  Missing data values;
     •  Outliers; and
     •  Units of measure.
     4.7.1  Reporting of Low and Zero Concentration Values
     A critical concern is the interpretation, reporting, and analysis of
GWCCs that are measured at less than (LT) a detection limit of an
analytical procedure.  These values, which are referred to as LT
detection  limit values, result for a variety of reasons, and enforcement
officers, during  the review of data submissions, may confront a variety
of codes which indicate that GWCC concentrations are below a value which
can be measured with certainty.
                                   4-23

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     Values that are LT a limit of detection can result when:
     •  GWCCs are present at extremely low concentrations;
     •  An insensitive analytical technique has been used; and
     •  The chemical matrix of the ground water interferes with the
        analytical technique.
     Low GWCC concentrations may be reported using various conventions
depending on the chemical constituent that was measured, the machine and
method used, the chemical analyst, or the data base/computer manager that
was responsible for automating the data in preparation for analysis and
reporting.  Enforcement officers may confront owner/operator data
submissions where the convention was to report a code for LT a limit of
detection with no accompanying number.  Alternately, the owner/operator
may submit data where the LT designation accompanies a number that is
consistent throughout the data for that analyte.  In otrier instances,
data submissions include LT designations which accompany numbers that
vary among samples.  Furthermore, some analytical results may
differentiate between GWCCs present but at concentrations that are LT a
limit of detection and GWCCs that are not present in the sample at all.
It is also possible that the enforcement officer will review data
submissions where the values that accompany a LT designation are
quantification limits rather than LT detection limit values.
Quantification limits are generally some multiple larger (5 or 10 times)
than the smallest concentration that can be measured.  It is clear that
the codes used to designate low GWCC concentrations may assume many forms
and may indicate different results; Table 4-2 provides a listing of some
low concentration codes that the enforcement officer is likely to
encounter in data submissions.  The purpose of Table 4-2 is not to
endorse particular reporting formats, but to prepare enforcement officers
for a variety of data submissions where low concentrations of GWCC are
reported with different codes  that may have different meanings.
                                   4-24

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                                          TABLE 4-2
              A LISTING AND DESCRIPTION OF CODES USED TO INDICATE THAT POLLUTANT
               CONCENTRATIONS WERE BELOW A CONCENTRATION WHICH CAN BE MEASURED
                      ACCURATELY OR THAT THE POLLUTANTS WERE NOT PRESENT
Definition of
P/yJpc
^^ the Acronyms
LOO-t- Limit of detection
LOQ+ Limit of quantifi-
cation
MDLf+ Method detection
limit
LT Less than
BDL Below detection
limit
<
Negative
signs
Trace*
K
ND* Not detected
Dashes*
Large
numbers*
Zeros*
Blanks*
Examples
of Use
LOD 0.421
LOQ 2.234
MDL 0.631
LT, LT 0.01
LT 0.148
BDL, BDL 0.01,
BDL 0.148
<0.01, <0.148
-0.01, -0.148
Trace, T
K0.01, K0.148
ND
—
999999
0

Used to Indicate
That the Pollutant
Was Less Than a
Limit of Detection
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Used to Indicate
That the Pollutant
Was Not Present
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
NOTES:

1.  The codes, marked with a +, are the codes used when the American Chemical  Society
    methodology is applied.

2.  The code, marked with a »•+, is the code that is used when the 40 CFR 136 methodology
    is applied.

3.  The Codes column lists examples of low concentration designations that may be included
    in data submissions.

4.  Several codes, marked with a *, have potential for being ambiguous.  Their meaning
    depends on laboratory reporting protocols and could either indicate that the value was
    LT a limit of detection or not present.
                                                4-25

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          The following guidelines should help the enforcement officer
identify problems associated with the reporting of LT detection limit
values and prescribe remedies for future owner/operator submissions:

     •  GWCC should be given close attention if the LT detection limit
        values appear to increase over time.  Increasing detection limits
        may be used to conceal an increasing concentration trend.
        Table 4-3 illustrates how changing detection limits make data
        interpretation difficult.

     •  Similarly, if background data are reported without a LT
        designation at low concentrations and comparison downgradient
        data are presented at higher concentrations with a LT
        designation, then it is possible that LT detection limit values
        are being used to conceal larger downgradient concentrations.

     •  It is unacceptable to report only qualitative information such as
        LT for values that were measured below a limit of detection.  The
        enforcement officer must ensure that numerical values accompany
        the LT designation so that data are available for analysis.

     •  LT detection limit values that are high or that vary should be
        reduced in future work by laboratory procedures that remove
        interfering constituents.

     •  The owner/operator must explain and follow the protocol for
        determining and reporting low concentration values. Enforcement
        officers should not allow the use of highly variable reporting
        formats.  Instead, the protocol used for determining and reporting
        GWCC data at low concentrations should conform with the technique
        described in Appendix B of 40 CFR §136 titled "Definition and
        Procedure for the Determination of the Method Detection Limit-
        Revision 1.11."  This method is similar to the methods proposed
        by the American Chemical Society.

     •  LT values should not be deleted from the analysis.  Instead,
        LT values may be analyzed at half their reported value.  This
        technique is simple to use and has been presented for use in
        the following references:

          Gilbert, R.O. and Kinnison, R.R.  1981.  Statistical Methods
          for Estimating the Mean and Variance from Radionuclide Data
          Sets Containing Negative, Unreported, or Less than Values.
          Health Physics 40:377-390.

          Nehls, G.J. and Akland G.G.  1973.  Procedures for Handling
          Aerometric Data.  Journal of the Air Pollution Control
          Association 23:180-184.
                                   4-26

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                           TABLE  4-3

     AN  EXAMPLE OF  A  DATA  SUBMISSION WHICH MAY  BE CONCEALING
       AN INCREASING CONCENTRATION TREND AND/OR WHERE THE
           UNITS OF MEASURE WERE REPORTED INCORRECTLY
    GROUND-WATER ARSENIC CONCENTRATIONS IN PARTS PER BILLION

   •  August, 1982                    1.54

   •  August, 1983                   <6

   •  November,  1983                 <11.000*


*Reported as 11  ppm.
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     4.7.2  Significant Digits
     All digits in a reported result that have been measured,  except for
the last right-hand digit (which may have been estimated visually), are
said to contain only significant digits.  Table 4-4 lists examples of data
values with their associated number of significant digits and identifies
instances in which the number of significant digits is ambiguous.
     Data values for each GWCC must be reported with consistent numbers
of significant digits.  Using the same number of significant digits
suggests that the constituents were measured with equal precision, subject
to the same round-off rules, and were generated and analyzed with care
and attention to detail,  several extra digits should be carried through
any statistical computations that are performed.
     Three ways that the number of significant digits can decrease is:
     •  With an order of magnitude decrease in the concentration of a
        chemical species;
     •  Reduced precision of the analytical methodology; and
     •  Rounding of the values.
     It is acceptable for the number of significant digits to decrease
if there has been an order of magnitude decrease in concentration, but
it is not acceptable to have a decrease in the number of significant
digits because a new analytical method with less precision has been
adopted or because significant digits have been rounded off.  Sometimes
it is possible to determine that data have been rounded off by comparing
data from one sampling episode with data from another sampling episode.
Rounding should not be allowed because the number of significant digits
that are reported is related to the precision of the measurement.  Round-
ing techniques should not be used to alter the apparent precision of a
measurement.  Similarly, if the laboratory, chemist, data base manager,
method, or units of measure change, then the number of significant digits
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                      TABLE  4-4
 EXAMPLES OF DATA VALUES AND THEIR ASSOCIATED NUMBER
                OF SIGNIFICANT DIGITS
                               Number of Significant
        Data Value                     „, .2
                                       Digits
        23,000*                          2

         3,437                           4

           567.31                        5

            25.01                        4

             1.67                        3

             0.30*                       2

             0.001**                     1

             0.128                       3

             0.120*                      3
 *The number of significant digits in the values with
  right-hand zeros is ambiguous and without the other
  values in the data set it is not possible to determine
  whether the right-hand zeros were measured.   In these
  examples the 23,000 value is assumed to be reported to
  the nearest 1000, the 0.30 is measured to the nearest
  100th, and 0.120 to the nearest 1000th.

**Left hand spacing zeros in values less than one are
  normally not considered as significant digits.
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may decrease.  Again, a decease in precision is unacceptable and should
be corrected,  correction and verification of this problem requires that
the owner/operator trace data to their earliest form which should be the
original laboratory records and laboratory technician who performed the
measurements.  If rounding occurred during data processing, the data can
be corrected.  However, if the chemical analysis method changed and
caused a reduction in precision, the owner/operator should be advised to
resume use of the prior methodology.
     The absolute number of significant digits should be sufficient to
provide reasonable accuracy.  A general rule to follow is that all of the
indicator parameters should be reported with at least three significant
digits.  The importance of measuring and retaining as many significant
digits as possible is illustrated in the following example.  For example,
if methylene chloride values are measured in vg/8, with two significant
digits and range from 65 to 73 then an error of plus or minus 1 yg/9.,
which is an error of one in the last significant digit, is an 11 percent
error.  In contrast, if the values were measured to the tenths of a
yg/8,, that is with three significant digits, and the values ranged
from 65.1 vg/8- to "73.1 V9/1- then an error of 0.1 in the last significant
digit of 65.1 would be only about a 1 percent error.  If it is difficult
operationally to measure a GWCC concentration with three significant
digits then, using the evaluation methodology described above in the
example, no more than a 10 percent error should be allowed with a one
unit change in the last significant digit of a data value.
     4.7.3  Missing Data Values
     Owner/operators incur a substantial risk of missing an extreme
environmental event and measurement of particularly large or small values
if they fail to collect all of the data required for a monitoring program.
This may result in an incomplete measure of environmental variability and
an increased likelihood of falsely detecting contamination.  Also, if
assessment monitoring data are missing there is a danger that the full
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extent of contamination may not be characterized,  owner/operators must
take extreme care to ensure that concentration measurements result from
all samples that are taken.  Nevertheless, the enforcement officer is
likely to confront situations where complete detection or assessment
monitoring data have not been collected.  The enforcement officer should
have the owner/operator perform the t-test despite incomplete data
collection, provided that the following criteria have been met:
     •  If there are data from one upgradient well and one downgradient
        well, statistical comparisons should still be made.  If data
        exists for three quarters at a well, statistical comparisons
        should be made after applying the rule described in the next
        bullet.
     •  If only one quarter of data is missing, values should be assigned
        for the four missing replicates.  These values should be obtained
        by averaging the values obtained during the other three quarters.
     •  If there are missing replicate measurements from a sampling
        event, then assign values obtained by averaging the replicate(s)
        which are available for that sampling event.
These guidelines have been described previously in the November 1983 EPA
memorandum on statistical analyses of indicator parameter data.  The
intent of this methodology is to force use of the t-test, despite prior
noncorapliance with the data collection requirements in the regulations,
so that a determination can be made as to whether assessment monitoring
should begin.  Regardless of whether there are sufficient data for
performing the t-test, the enforcement officer should consider taking
enforcement action to compel additional sampling on an accelerated
schedule (see Chapter Five of the RCRA Ground-Water Monitoring Compliance
Order Guidance).  The enforcement officer must minimize delays in the
evaluation of a facility's ground water because of prior incomplete data
collection.
     4.7.4  Outliers
     A GWCC value that is much different than most other values in the
data for the same GWCC maybe referred to as an "outlier."  The reasons
for outliers can be due to:

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     •  A catastrophic unnatural occurrence such as a spill;
     •  Inconsistent sampling or analytical chemistry methodology;
     •  Errors in the transcription of data values of decimal points;
        and
     •  True but extreme GWCC concentration measurements.
     The enforcement officer should attempt to have owner/operators
correct outlying values if the cause of the problem can be documented and
corrected by the owner/operator without delay.  The data should be
corrected if outliers are caused by incorrect transcription and the
correct values can be obtained and documented from valid owner/operator
records.  Also, if an unnatural catastrophic event or methodological
problem occurred, which can be documented, then data values should be
from calculations with clear reference to this deletion at all relevant
stages.  Documentation and validation of the cause of outliers must
accompany any attempt to correct or delete data values, because true but
extreme values must not be altered.  The enforcement officer should not
accept the mere presence of an extreme value in data or the effect of an
extreme value on the statistical analysis as a valid reason for the
continuation of detection monitoring.
     4.7.5  Units of Measure
     Associated with each GWCC value is a unit of measure which must be
reported accurately.  Mistakes in the reporting of the units of measure
can result in gross errors in the apparent concentrations of GWCCs.  For
example, a lead value of 30.2 might have a unit of measure of parts per
billion (ppb).  Alternately, the same lead value of 30.2 might have been
incorrectly reported with a unit of measure in parts per million  (ppm).
The reported value would transform to a concentration with the units of
measure in ppb as 30,200 ppb of lead or three orders of magnitude larger
than it was measured.  Table 4-3 presents an example of a data submission
which  included a value that was probably reported with incorrect  units of
measure.
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     The following guidelines should help the enforcement officer ensure

that data values are reported consistently and unambiguously:

     •  The units of measure should accompany each chemical parameter
        name.   Laboratory data sheets that include a statement "values
        are reported in ppm unless otherwise noted" should generally be
        discouraged but at least reviewed in detail by the enforcement
        officer.  It is common to find errors in reporting the units of
        measure on this type of data reporting sheet.

     •  The units of measure for a given chemical parameter must be
        consistent throughout the report.

     •  Finally, reporting forms for detection monitoring, as specified
        in the EPA November 1983 memorandum, and the data presentation
        methods described in Chapter Five should help to reduce problems
        associated with the reporting of units of measure.
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                               CHAPTER FIVE
             STATISTICAL ANALYSIS  OF DETECTION MONITORING DATA

     Owner/operators of hazardous waste facilities must implement a
ground-water monitoring program capable of determining if a facility has
had a significant effect on the quality of the ground water.  This deter-
mination is based on the results of a statistical test.  This chapter
discusses the data that should be collected to perform the statistical
test, and what actions should be taken based on the results of the
statistical test.  A general description of statistical techniques is
described below.  A more specific description, which includes the
computational details and an example, appears in Appendix B.
     5.1  Methods for Presenting Detection Monitoring Data
     Data reporting sheets such as  those presented in the November 30,
1983, EPA memorandum titled "Guidance on Implementation of Subpart F
Requirements for Statistically Significant Increases in Indicator
Parameter Values" should be used when owner/operators present data as
required by §265.94(a).  The enforcement official should make sure that
owner/operators are aware of and use standardized data reporting sheets.
     The enforcement official should have in  the file all of the ground-
water data that have been collected to date from the facility.  An
explicit presentation of the statistical test methodology should also
be in the file for the  facility.
     5.2  Introductory  Topics:  Available t-Tests, Definition of Terms,
          and Components of variability
     Several introductory topics are discussed in this section which
pertain to the statistical analysis of detection monitoring data.  First,
the statistical tests that the owner/operator can use to analyze detection
monitoring data are discussed.  Then definitions of the terms background,
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upgradient, and downgradient are presented.  Finally,  the measurement of
environmental variability and its relationship to the number of upgradient
wells, analytical replicates, and the statistical test that should be
used is reviewed.
     The interim status regulations specify that a students t-test be
used to determine whether there has been a significant increase in any
ground-water contamination indicator parameter (IP) in any well.  The
§265 regulations do not, however, require a specific students t-test.
The owner/operator has the latitude within the regulations to choose a
t-test which will accommodate the data that have been collected.  One
reason that interim status facilities frequently adopt the Cochran's
Approximation to the Behrens-Fisher (CABF) t-test is that the §264 permit
regulations require the use of the CABF t-test, unless an equivalent
statistical test is accepted by the Regional Administrator.  Other
t-tests are available for the owner/operators to use in th  malysis of
their interim status detection monitoring data.  One alternative t-test,
which has been recommended for use in public comment and in the November
1983 memorandum on interim status statistical analyses, is referred to as
the averaged replicate  (AR) t-test.  The AR t-test is a reasonable test
for owner/operators to apply to their interim status detection monitoring
data because it removes the excessive weight that the analytical or split
sample replicates have on the background variability and may help reduce
statistically caused false positives.  The owner/operator may perform the
t-test of choice, but the results must be presented and action  taken
based on the results of only one type of t-test.
     It should be noted that although owner/operators have  latitude with
respect to  the statistical  test  that is used,  there is much less choice
with  regard to the data collection requirements.  Also, despite which
t-test is used the comparisons which are required to be made must not
change.  A  general example of the  last two points is  that,  regardless of
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'              the t-test the owner/operator has decided to use, a background data set
              should be collected and compared to the data from each well individually
              each time they are sampled.
i                   Three terms which are used frequently in discussions regarding
|              the interim status detection monitoring statistical analysis are:
:              background, upgradient, and downgradient.  The terms upgradient and
;              downgradient describe well locations (e.g., with respect to the ground-
              water hydraulics) and performance (e.g., downgradient wells must be able
'              to immediately detect contamination).  The terms upgradient and down-
;              gradient also describe the data collected from those wells.  The term
:              background refers to a special set of upgradient data that should have
i              been collected beginning in November 1981 and ending in November 1982
'              from all the wells upgradient and unaffected by the facility.  In
              addition, unlike references to upgradient or downgradient data which
'              are well specific, references to background data concern all data
              collected from all upgradient wells during the period when background
              levels are being established.  It may also be necessary, during the
              administration of enforcement cases when background data have not been
              collected properly, to require accelerated data collection and have
              background data collected concomitantly with the data collected from the
              downgradient wells.
                   The issue of the components of variability in background ground-
              water data have been of concern to enforcement officials.  The concern
              has been that some owner/operators historically have had a tendency to
              install the minimum of one upgradient well.  The result is a background
              data set which includes no component of spatial variability because only
              one upgradient well has been sampled.  Also, the background data are
              influenced heavily by analytical variability because of the requirement
              to obtain four measurements per sample.  The split sample replicates are
              valuable for ensuring that owner/operator laboratories are operating with
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a degree of quality control.  However, the background data set should
also include a component of spatial variability and not be influenced
heavily by the typically small component of analytical variability.
Many owner/operators have installed a minimum, but not necessarily
acceptable, number of upgradient wells (e.g., one upgradient well).  Two
recommendations are provided to help with this problem.  First, the
owner/operator should install additional upgradient wells to ensure
measurement of spatial variation in the ground waters in the upgradient
area.  Second, the AR t-test can be used by owner/operators to
essentially remove the excessive influence that the analytical replicate
variability has on the CABF t-test.
     5.3  Statistical Analysis of the First Year's Data
     As described above, owner/operators should have measured the back-
ground concentrations of ground-water parameters within one year of the
effective date of the interim status Subpart F regulations.  The initial
background concentrations of the Appendix III parameters in §265.92(b)(1),
the ground-water quality parameters in §265.92(b)(2), and the ground-water
contamination (or indicator) parameters in §265.92(b)(3) should have been
established by monitoring upgradient wells quarterly for a year.  Four
replicate measurements should have been obtained from each well during
each sampling episode for the indicator parameters.
     The background mean and variance should have been determined using
all of the data obtained for the §265.92(b)(3) parameters during the
first year of sampling from the wells that were upgradient of the
facility.  It should be noted that one primary difference between the
CABF t-test and the AR t-test is the method used to determine the
background mean and variance.  These summary statistics, which describe
the background concentrations, form the basis against which all subsequent
upgradient and downgradient concentration measurements will be compared.
The methods used to estimate the background mean (X, ) and variance (s. )
                                                   b                 b
for the CABF and AR t-tests are described in Appendix B.
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     5.4  statistical Analysis of Detection Monitoring Data After the
          First Year
     Detection monitoring data collected after the first year should be
used to compare with the background data to determine if there is a
suggestion that contamination may have occurred.  A t-test is used to
make this determination.  A significant increase in the mean concentration
of any IP in any downgradient well, that is statistically larger than the
background concentration, suggests that contamination may have occurred.
(NOTE:  In the case of pH, the t-test is conducted such that an increase
or decrease is detected.  All future references to significant statistical
increases imply in the case of pH that a significant statistical change
is being evaluated.)
     All of the upgradient and downgradient wells must be sampled after
the first year.  The ground-water quality parameters in §265.92(b)(2)
must be measured at  least annually but are not analyzed statistically.
The IPs in §265.92(b)(3) must be measured in at least four replicate
measurements from each sample from each well in the detection monitoring
network at least semi-annually.
     The data collected must be used to calculate an arithmetic mean
and variance at least semi-annually for each IP from each well.  The
methodology for computing the mean and variance from data collected after
the first year is the same methodology used to compute  the background
mean and variance.
     5.4.1  Comparison of Background Data Collected the First Year With
            Upgradient Data Collected in Subsequent Years
     When the t-test for an upgradient well as required by §265.93(c)(1)
shows a significant  increase in the concentration of an IP,  there is a
suggestion that IP concentrations  in the upgradient ground water may be
increasing.  There are several reasons why  the statistical test may
indicate that the upgradient concentrations have increased.  These
include:
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     •  Ground-water flow direction was determined incorrectly and
        hazardous waste constituents have migrated into the upgradient
        wells.

     •  Ground-water flow direction was determined correctly,  but
        hazardous waste constituents are moving in a direction that is
        opposite of the ground-water flow.

     •  Upgradient wells were located in a mound caused by the facility.

     •  A source of contamination unrelated to the facility was detected.

     •  An inconsistent methodology (e.g., well construction materials,
        sampling and analysis techniques) has been used which resulted in
        concentration differences that are unrelated to any change in the
        concentration of IPs in the ground water.

     •  The t-test falsely indicated a difference between the background
        data and upgradient data when actually there was no difference.

     The cause of the increase in upgradient concentrations will be

important to the enforcement official if the owner/operator establishes

successfully during the first determination under assessment that no

contaminants have entered the ground water.  Prior to reinstating the

detection monitoring program the owner/operator may request that, because

of the increase in background concentrations identified with the back-

ground versus upgradient comparisons, the historical data are unrepre-

sentative of background conditions and should be modified.

     Several recommendations are presented which will help the enforcement
officer decide whether and how the background data set can be corrected:

     •  The enforcement officer should require that the owner/operator
        perform the following prior to modification of the background
        data.  First, it must be explained exactly why the background
        data set should be modified.  These demonstrations must be based
        upon data and considerations which are documented thoroughly.
        The owner/operator must also indicate specifically how the
        background data set will be modified.  Finally, it must be shown
        that changes in the background data will not delay  the
        ground-water sampling and  anlaysis program.
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     •  Before any modifications are made to the data the enforcement
        official should make sure that it is not possible to conduct the
        statistical comparisons using existing data.   Although some data
        sets have a sparse amount of data, it may be  possible to use the
        recommendations in the section on missing data to impute the
        values that were not collected and still make a statistical
        comparison of background versus downgradient  data.  It may also
        be possible to use data that were collected from upgradient
        wells after the first year.

     •  Many data sets will be unusable because of unacceptable
        analytical chemistry, hydrogeological considerations, or the
        physical construct of the well system, for example, when
        wells have been located in an area affected by the facility.
        Modification of the background data set may require installation
        and sampling of a new well system.  In this case, it may be
        necessary to require that background data from upgradient wells
        be collected on an accelerated schedule concomitantly with
        downgradient data.

     5.4.2  Comparison of Background Data Collected During the First Year
            With Downgradient Data Collected in Subsequent Years

     When the t-test for a downgradient well shows a significant increase
this suggests that the facility may be affecting the ground water.  The

owner/operator must immediately resample and collect  multiple ground-water
samples from those downgradient wells where a significant increase in
concentration was detected as required by §265.93(c)(2).  The additional
ground-water samples are to be split in two and analyzed to determine by
reapplying the t-test using the resampling data whether the significant

increase was a result of laboratory error or the result of ground-water
contamination,  if the initial results are due to laboratory error and no
significant increase has occurred, the detection program may continue.

     If the additional analyses performed under §265.93(c)(2) confirm the

significant increase, the owner/operator's facility is in interim status
assessment monitoring and must, without exception, begin immediately the
requirements of assessment monitoring.  Ground-water contamination cannot
be evaluated satisfactorily with a continuation of detection monitoring.
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     It is essential that the enforcement official determine that all
data collected from the site hydrogeologic characterization is adequate
to define the vertical and horizontal extent of the saturated zone of
potential contamination.  The reliability of all phases of the site
ground-water monitoring program and the efficacy of any subsequent
corrective action efforts hinge upon the quality of the owner/operator's
site hydrogeologic characterization.
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                                CHAPTER  SIX

                           ASSESSMENT MONITORING


     Once the owner/operator has detected contaminant leakage via his
detection monitoring efforts, the owner/operator must undertake a more

aggressive ground-water program called assessment monitoring.  Specifi-

cally, the owner/operator must determine the vertical and horizontal

concentration profiles of all the hazardous waste constituents in the
plume(s) escaping from waste management areas.  In addition, the owner/
operator must establish the rate and extent of contaminant migration.
The blueprint for an assessment monitoring program is the owner/operator's
written assessment monitoring plan.  This is an extremely important

document, serving several purposes:

     1.  It presents a detailed procedure for determining the rate of
         migration, extent, and hazardous waste constituent composition
         of the release.

     2.  It provides a mechanism for obtaining data necessary to the
         permit application process, principally the §270.14(c)
         information requirement.

     3.  It provides a mechanism for obtaining data necessary for
         subsequent corrective actions at facilities.

     The Agency has observed a number of problems in the way owner/
operators prepare and/or implement their assessment monitoring plans.

     •  Many owner/operators lack satisfactory knowledge of site
        hydrogeologic conditions.  As a result these owner/operators
        cannot make informed decisions on how to carry out their
        assessment programs.  The owner/operator should have collected
        abundant site hydrogeologic information prior to the installation
        of the detection monitoring system in the site characterization
        phase.

     •  Many owner/operators fail to provide enough information in
        their assessment plans to allow the Agency to scrutinize their
        decision-making or to evaluate their assumptions.
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     •  Some owner/operators fail to implement their assessment programs
        quickly enough or they implement programs that will take too long
        to provide information on plume extent and migration.

     •  Some owner/operators do not support geophysical investigation
        with a sufficient monitoring well network.  Geophysical methods
        are valuable in confirmation of conclusions through sampling and
        as in interpolative tool between wells, but they are insufficient
        at present by themselves.

     •  Many owner/operators greatly underestimate the level of effort
        the Agency expects of them in characterizing plume migration.
        In most cases, assessment monitoring is an intensive effort that
        will require the owner/operator to install numerous monitoring
        wells.  The owner/operator must track and characterize both the
        horizontal and vertical components of the plume (i.e., a three
        dimensional characterization).

     •  Many owner/operators do not follow their written plans or fail to
        update their plan on the basis of information gained through
        assessment programs.

     For facilities in assessment monitoring the enforcement official's

main emphasis should be on (1) scrutinizing the adequacy of the owner/

operator's written assessment monitoring plan; and (2) reviewing the

owner/operator's implementation of the plan in the field.

     There are a number of elements that the owner/operator should

include in the assessment monitoring plan.

     •  narrative discussion of the hydrogeologic conditions at the
        owner/operator's site: identification of potential contaminant
        pathways (Section 6.1);

     •  description of the owner/operator's detection monitoring system
        (Section 6.2);

     •  description of the approach the owner/operator will use to make
        the first determination (false positives rationale) (Section 6.3);

     •  description of the investigatory approach the owner/operator
        will use to fully characterize rate and extent of contaminant
        migration; identification and discussion of investigatory phases
        (Section 6.4);
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     •  discussion of number, location and depth of wells the owner/
        operator will initially install as well as strategy for
        installing more wells in subsequent investigatory phases
        (Section 6.5);
     •  information on well design and construction (Section 6.6);
     •  a description of the sampling and analytical program the
        owner/operator will use to obtain and analyze ground-water
        monitoring data (Section 6.7);
     •  description of data collection and analysis procedures the
        owner/operator plans to employ (section 6.8); and
     •  a schedule for the implementation of each phase of the assess-
        ment program (Section 6.9);
     6.1  Description of Hydrogeologic Conditions
     An owner/operator cannot conduct an adequate assessment monitoring
program without a thorough understanding of site hydrogeologic
conditions.  A thorough understanding of hydrogeologic conditions,
garnered through site characterization activities (refer to Chapter One),
allows the owner/operator to identify likely contaminant pathways.
Identification of these pathways allows the owner/operator to focus
efforts on tracking and characterizing plume movement.  It is important
to note that the initial site characterization carried out by the owner/
operator should provide enough hydrogeologic information to allow the
owner/operator to not only design a detection monitoring system but also
plan and carry out an assessment monitoring program.  Except for cases
where some additional site information is needed (see §6.5.1), the
owner/operator should not, as part of the assessment monitoring program,
conduct hydrogeologic site characterization.  This characterization
should have been completed prior to the design of detection monitoring
systems.
     The owner/operator's assessment plan should describe in detailed
narrative form what hydrogeologic conditions exist at the owner/operator's
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site.  The plan should describe the potential pathways of constituent
migration at the site including depth to water in aquifer, aquifer
connections to surface water and/or deeper aquifers, flow rate and
direction, and any structions such as fractures and faults which could
affect migration.  The owner/operator's plan should also describe how
hydrogeologic conditions have influenced the type of assessment effort
that will be used to characterize plume migration.  This portion of the
owner/operator's assessment plan should recapitulate the hydrogeologic
investigatory program the owner/operator undertook prior to installing a
detection monitoring system (see Chapter One).  It should describe the
investigatory approach the owner/operator used to characterize subsurface
geology and hydrology, the nature and extent of field investigatory
activities, the results of the investigation, and explicit discussion as
to how those results have guided decisions the owner/operator has made in
regards to the planning and implementation of his assessment monitoring
program.  As part of the plan, the owner/operator should append various
supporting documentation such as those described in Table 1-1.
     6.2  Description of Detection Monitoring System
     The owner/operator's assessment plan should describe the detection
monitoring system in place at the owner/operator's facility.  Of key
concern is that the existing well system is capable of detecting all
contaminant leakage that may be escaping from the facility.  If the
owner/operator's detection monitoring system is deficient either in
design or operation, plumes may escape the notice of the owner/operator.
This portion of the owner/operator's assessment plan should describe the
physical layout of the owner/operator's detection monitoring well system
(e.g., horizontal and vertical orientation of individual wells) and
identify assumptions the owner/operator used in designing the detection
monitoring system (particularly how hydrogeologic condition affected
decision making).
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     6.3  Description of Approach for Making First Determination -
          False Positives
     Chapter Five described requirements that owner/operators must meet
in terms of statistical analysis of detection monitoring data.  Once an
owner/operator has verified a statistically significant increase in
contaminant concentration in a well(s), the owner/operator must shift
from detection to assessment monitoring.  Figure 6-1 illustrates the
sequence of events that occur once an owner/operator shifts to assessment
monitoring.  Of particular interest are those situations where the
owner/operator feels that contamination may have been falsely indicated
and describes in his assessment plan a short term program to substantiate
or disprove the false positive claim (i.e., false positive investigation
is focus of first determination - §265.93(d)(5)).
     Assessment plans focusing on substantiating a false positive claim
should only be entertained when an owner/operator's detection monitoring
system is properly designed.  If an owner/operator's detection monitoring
system is inadequate, it is difficult to evaluate whether leakage has
occurred by sampling for specific constituents in the existing monitoring
network.  Substantiation of a false positive claim would be a lengthy
process potentially involving hydrogeologic work, the installation of a
new detection well network and additional sampling.  In those cases,
officials should reject a false positive analysis as the focus of the
first determination when the existing system is inadequate and instead
require the owner/operator to (1) correct deficiencies in the detection
monitoring system; and (2) concurrently initiate a comprehensive
assessment program downgradient from the triggering well(s).
     If, however, an owner/operator's detection monitoring system is
adequately designed, the owner/operator may propose as his first
determination a short-term sampling program—generally no longer than
30 days- that will investigate whether the statistical change noted in
Part 265 indicator parameters truly represents migration of leachate into
                                    6-5

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                             OWNER/OPERATOR CONDUCTS
                          STATISTICAL ANALYSIS - SIGNIFICANT
                          INCREASE INDICATED (CHANGE FOR pH)
                       OWNER/OPERATOR IMMEDIATELY RESAMPLES •
                           SIGNIFICANT INCREASE VERIFIED
                                        T
                           FACILITY SHIFTS FROM DETECTION
                             TO ASSESSMENT MONITORING
                         OWNER/OPERATOR NOTIFIES REGIONAL
                           ADMINISTRATOR WITHIN 7 DAYS OF
                                VERIFYING INCREASE
                                        i
                          OWNER/OPERTOR SUBMITS ASSESSMENT
                           PLAN WITHIN 15 DAYS OF VERIFYING
                           INCREASE; OWNER/OPERATOR MAKES
                       FALSE POSITIVE CLAIM IN ASSESSMENT PLAN
                           BEGINS IMMEDIATE IMPLEMENTATION
                               OF SHORT TERM (30 DAYS)
                              SAMPLING PROGRAM AS FIRST
                                   DETERMINATION
                               REGIONAL ADMINISTRATOR
                            ENTERTAINS OWNER/OPERATOR'S
                               FALSE POSITIVE CLAIM IF:

                           • OWNER/OPERATORS DETECTION
                             MONITORING SYSTEM IS PROPERLY
                             DESIGNED; AND

                           • OWNER/OPERATOR ADVANCES A
                             SHORT TERM SAMPLING PROGRAM
                             WHICH FOCUSES ON APPENDIX VIII
                             CONSTITUENTS
                        f
          t
             CONTAMINATION CONFIRMED;
              OWNER/OPERATOR BEGINS
          FULL CHARACTERIZATION OF PLUME(S)
FALSE POSITIVE INDICATED;
OWNER/OPERATOR RETURNS
TO DETECTION MONITORING
FIGURE 6-1. PROCEDURE FOR EVALUATING FALSE POSITIVE CLAIMS BY OWNER/OPERATORS
                                     6-6

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the uppermost aquifer.  For units subject only to the Part 265 standards,
the short-term sampling program must, at a minimum, confirm that no
hazardous waste constituents (Appendix VII) have migrated into the
uppermost aquifer.  For units subject to the Part 270 requirements
(because they are seeking an operating permit or the Agency has called
in their post-closure permit), the owner/operator should include
constituents selected from Appendix VIII in the sampling program.
     After conducting the short-term sampling program (constituting the
first determination), the owner/operator must submit to the Regional
Administrator a written report describing the ground-water quality.  If
the sampling program confirms that leakage has not occurred, the
owner/operator may reinstate the detection monitoring program or enter
into a consent agreement with the Agency to follow a revised detection
protocol designed to avoid future false triggers.  If, however, the
short-term sampling confirms that leakage has in fact occurred, the
owner/operator must immediately begin implementation of assessment
activities to characterize rate and extent of contaminant migration.
     6.4  Description of Approach for Conducting Assessment
     A variety of investigatory techniques are available for use during
a ground-water quality assessment.  They can be broadly categorized as
either direct or indirect methods of investigation.
     All assessment programs should be designed around the direct method
of actual collection of a sample with subsequent chemical analysis to
determine actual water quality (i.e., installation of monitoring wells).
Other methods of investigation may be used when appropriate to choose the
locations for well construction.  For certain aspects of an assessment,
such as defining plume location, the use of both direct and indirect
methods may be the most efficient approach.
     The methods planned for use in an assessment should be clearly
specified and evaluated to ensure that the performance standard
                                    6-7

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established for assessments can be met.  Evaluating the use of direct
and indirect methods are discussed separately below.
     6.4.1  Use of Direct Methods
     Ground-water monitoring wells, either existing or newly installed,
are necessary to provide sampling data to establish the concentration of
hazardous constituents released from the hazardous waste management, and
the rate and extent of their migration.  The owner/operator should
construct assessment monitoring wells and conduct sampling and analysis
in a manner that provides reliable data.  Chapters Three and Four,
respectively,  present guidance in these areas.
     At facilities where it is known or suspected that volatile organics
have been released to the uppermost aquifer, organic vapor analysis of
soil gas from shallow holes may provide an initial indication of the
areal extent of the plume.  To this end, the owner/operator may use an
organic vapor analyzer (OVA) to measure the volatile organic constituents
in shallow hand-augered holes.  Alternatively, the owner/operator may
extract a sample of soil gas from a shallow hole and have it analyzed in
the field using a portable gas chromatograph.  These techniques are
limited to situations where volatile organics are present.  Further, the
presence of intervening, saturated, low permeability sediments strongly
interferes with the ability to extract a gas sample.  Although it is not
necessarily a limitation, optimal gas chromatography results are obtained
when the analyte is matched with the highest resolution technique, e.g.,
electron capture/halogenated species.
     Descriptions of the direct methods that will be employed during
assessment monitoring should be included in the assessment plan.  These
descriptions should be sufficiently detailed to allow the method to be
evaluated and to ensure that the method will be properly executed.
     6.4.2  Use of Indirect Methods
     A variety of methods are currently available for identifying and,  to
a limited extent, characterizing contamination in the uppermost aquifer.
                                    6-8

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There are several geophysical techniques of potential use to an owner/
operator including electrical resistivity, electromagnetic conductivity,
ground penetrating radar, and borehole geophysics.  Remote sensing and
aerial photography are additional indirect methods an owner/operator may
find useful.  These techniques, with the exception of aerial photographic
methods, operate by measuring selected physical parameters in the
subsurface such as electrical conductivity, resistivity, and temperature.
     The value of indirect methods is not the provision of detailed,
constituent-specific data for which they presently are clearly limited,
but rather for demarcating the general areal extent of the plume.  This
is extremely important to the owner/operator for two reasons:
     1.  Knowing the outline of the plume before additional wells are
         constructed reduces the need for speculative wells.  The
         assessment monitoring program therefore becomes more efficient
         since well placement is guided by analytical data.
     2.  As the plume migrates and its margins change, the owner/operator
         may track its motion and see where new wells may be needed.
     There are drawbacks to the exclusive use of geophysical techniques
in assessment monitoring relating to the high level of detail necessary
to characterize the chemical composition of a ground-water plume.  For
these methods to be successful in this way the contaminant(s) of interest
must induce a change in the subsurface parameter measured.  This change,
in turn, must be distinguishable from ambient conditions.  For example,
the electrical properties of organic hazardous constituents are generally
attenuated or masked by subsurface material properties.  Unless these
constituents are present in a thick, immiscible layer, they generally
will not register during resistivity or conductivity surveys.  Moreover,
nonuniform subsurface conditions may obscure low levels of certain
contaminants in ground water.  Another drawback to the exclusive use of
geophysical methods at present is their inability to measure specific
concentrations of individual constituents or provide good vertical
resolution of constituent concentration.  In addition, man-made struc-
tures such as powerline towers, buried pipelines,  roads, and parking lots
                                    6-9

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may interfere with the performance and reliability of may geophysical
methods.  The owner/operator should therefore only use indirect methods
to guide the installation of an assessment monitoring system and to
provide an ongoing check of the extent of contaminant migration.
     6.4.3  Mathematical Modeling of Contaminant Movement
     Mathematical and/or computer modeling may provide information useful
to the owner/operator during assessment monitoring.  The owner/operator
should not, however,  depend solely on mathematical models to guide the
placement of assessment monitoring wells.  The high spatial and temporal
variability of conditions encountered in the field do not lend themselves
to the simplification and assumptions necessary to model something as
highly site-specific as an assessment of the extent and rate of migration
of a contaminant plume.  Furthermore, such extensive initial data is often
required as to render unclear what benefit is derived from modeling as
opposed to using direct or indirect methods.
     Where a model is to be used, the owner/operator should make site-
specific measurements to verify the parameters to be used in the model.
The hydrologic parameters required to describe saturated flow include:
hydraulic conductivity (vertical and horizontal); hydraulic gradient;
specific yield (unconfined aquifer) or specific storage (confined
aquifer).  The parameters required to describe contaminant flow include
the apparent velocity of the pollutant, dispersion and diffusion coeffi-
cients of the pollutants in the medium, the adsorbtion of pollutants in
the medium (retardation), and factors necessary to describe degradation
of pollutants.  The dispersion coefficient is a function of the apparent
velocity and dispersivity, and cannot be directly measured unless an
extensive test with tracers Is performed.  Retardation calculations are
based on soil bulk density, effective porosity and cation exchange
capacity.  Retardation can also be determined from the octanol-water
partition coefficient and fractional portion of organic matter in
                                   6-10

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representative volumes of soil.  Degradation of pollutants depend upon
the type of constituents and the probability for chemical and biological
decay.
     Background ground-water quality (e.g., indicator parameters plus
               +         +    +     -     =
Cl ,  Fe, Mn, Na ,  804, Ca ,  Mg , NC>3 ,  PO$ , silicate, ammonium,
alkalinity or acidity) is important to determine the reactivity and
solubility of hazardous constituents in ground water and therefore is
useful in predicting their mobility under actual site conditions.  The
physical and chemical characteristics of the site-specific wastes (e.g.,
density, solubility, vapor pressure, viscosity, and octanol-water
partition coefficient) and hazardous waste constituents should also be
known to reliably model constituent movement.
     Mathematical models can be analytical equations by which the
hydraulic head or concentration of a contaminant at any location are
calculated.  The phrase "mathematical models" is more often used to refer
to algorithms that represent the governing equations of water flow and
mass transport that can only be solved with computers.  The use of
computer models enables an analysis of complex conditions that better
describe the actual environment.  Any model requires the recognition of
inherent assumptions, the application of appropriate boundary conditions,
and the selection of a coherent set of input parameters.
     Required parameters that can be measured directly should be
determined with consideration of selecting representative samples and
with an understanding of how input of a parameter will influence the
output (e.g., affect of assuming homogeneous conditions in a heterogeneous
environment).  All parameters measured or assumed and adjusted during
model calibration should be reasonable and varied within reasonable
ranges.  Modeling is not only useful in guiding direct measurements, but
can also be useful in predicting future events.  When applying all
models, emphasis should be placed on the usefulness of the model to the
                                   6-11

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specific problem at the site, calibration and verification with past and
present data, and careful application in the predictive mode.
     A partial list of computer models that could be employed at a site
include:  Modular 3-Dimensional Finite Difference Groundwater Flow Model
(USGS), to evaluate complex hydrologic conditions; computer Model of
Two-Dimensional Solute Transport and Dispersion in Ground Water (USGS) or
the Illinois State Water Survey Random Walk Solute Transport Model, to
predict contaminant transport; the AT123D model to calculate concentra-
tions isopleths for transient contaminant flow in one, two, or three
dimensions under hydraulic flow conditions; and the FEMWASTE model,
developed by Oakridge National Laboratory,  which can predict contaminant
migration in both the saturated and unsaturated zones.
     If an owner/operator plans to use a model to guide an assessment
monitoring program, the owner/operator must be able and willing to
describe how the model works as well as explain all assumptions used in
applying the model to the site in question.
     6.5  Description of Sampling Number, Location, and Depth
     The regulations require that the assessment plan specify the number,
location and depth of wells that will be installed as part of the
assessment.  As the discussion on assessment methodology provided in
Section 6.4 has indicated, the owner/operator may use other sampling
techniques (e.g., indirect methods and coring) in addition to the
installation of permanent monitoring wells to augment the data generated
by wells during assessment.  The owner/operator's assessment plans
should, however, specify the number, location, and depth of wells that
will be installed to characterize rate and extent of migration, and
constituent concentrations, and present explanations for the decisions.
     It may not always be possible for the owner/operator to identify at
the outset of an assessment the exact number, location, and depth of all
sampling that will be required to meet the goals of an assessment.  In
                                   6-12
4

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many cases the investigations undertaken to characterize contamination
during an assessment will proceed in phases in which data gained in one
round of sampling will guide the next round of sampling.  For example,
surface geophysical techniques can be effectively used in tandem with the
installation of monitoring wells as a first phase in the assessment
program to obtain a rough outline of the contaminant plume.  Based on
these findings, a sampling program may subsequently be undertaken to more
clearly define the three-dimensional limits of the contaminant plume.  In
the third phase, a sampling program to determine the concentrations of
hazardous waste constituents in the interior of the plume may be under-
taken.  In this case, a detailed description of the approach that will be
used to investigate the site should be included in the assessment plan.
This description should clearly identify the number, location, and depth
of any sampling planned for the initial phase of the investigation.  In
addition, the outline should clearly identify what basis will be used to
select subsequent sampling locations, including the geologic strata that
are likely to be sampled and the anticipated density of sampling.  In
general, a minimum of seven well clusters should be installed to define
the extent of contamination and concentration of contaminants in the
horizontal plane (see Section 6.5.2).  Each well cluster should consist
of a minimum of five wells at varing depths to profile the vertical
extent of migration (see Section 6.5.3).
     6.5.1  Collection of Additional Site Information
     The hydrogeologic site characterization requirements for the
detection monitoring program include:
     •  The subsurface geology below the owner/operator's hazardous waste
        facility.
     •  The vertical and horizontal components of flow in the uppermost
        saturated zone below the owner/operator's site.
     •  The hydraulic conductivity of the uppermost aquifer.
     •  The vertical extent of the uppermost aquifer down to the first
        confining layer.
                                   6-13

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If this characterization does not include all the hydrogeologic infor-
mation necessary to characterize the rate of contaminant movement, the
owner/operator should obtain this additional information for the assess-
ment phase.  Examples of the additional information that may be needed to
determine the rate of contaminant movement include:  mineralogy of the
materials in the migration pathway; ion exchange capacity of the material;
organic carbon content of the materials; background water quality of the
pathway (e.g., major cations and anions); the temperature of ground water
in the migration pathway; and the effective porosity of the material in
the pathway.  This information will help define the transport mechanisms
which are most important at the site.  All information collected during
the investigation of the plume (i.e., boring logs, core analysis, etc.)
should be recorded and the hydrogeologic descriptions of the site updated
when appropriate.
     Prior to assessment well placement, a good estimation of plume
geometry can be determined from a review of current and past site charac-
terizations.  For example, piezometer readings surrounding the contami-
nated detection well can be taken to determine the current hydraulic
gradient.  When these values are compared to the potentiometric surface
map developed during the site investigation, the general direction of
plume migration can be approximated.  Any seasonal or regional fluctua-
tions should be considered during this comparison.  A review of the
facility's subsurface geology may also identify preferential pathways of
contaminant migration.
     To limit drilling speculative wells, geophysical and modeling
methods can also be employed to yield a rough outline of the plume.  This
expedites the assessment monitoring program.  Monitoring wells can then
be strategically placed to precisely define the plume geometry.
     6.5.2  Sampling Density
     The program of sampling undertaken during the assessment should
clearly identify the full extent of hazardous waste constituent migration


                                   6-14                                        *
C

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and establish the concentration of individual constituents throughout
the plume.  In the initial phase of the assessment program the owner/
operator's well installation/sampling should concentrate on bounding
those areas that have been contaminated by the facility.  A minimum of
seven well clusters should be installed to define the extent of contami-
nation and concentration of contaminants in the horizontal plane as
illustrated in Figure 6-2.  Three well clusters should be installed in
a line downgradient from the triggering well  cluster.  Two of these
clusters should be installed in the plume; one cluster should be
installed beyond the plume.  Four well clusters should be installed in a
line that is perpendicular to the direction of contaminant flow.  Two of
these clusters should be installed in the plume, and two of these
clusters should be installed beyond the plume.  This network of
monitoring wells, with a minimum of seven wells, will thoroughly define
the horizontal boundaries of the plume, and will identify and quantitate
contaminants.
     The well density or amount of sampling undertaken to completely
identify the furthest extent of migration should be determined by the
variability in subsurface geology present at the site.  Formations such
as unconsolidated deposits with numerous interbedded lenses of varying
permeability or consolidated rock with numerous fracture traces will
require a greater amount of sampling to ensure that all contamination is
detected.
     Sampling is also required to characterize the interior of any plume
detected at the site.  This is important because the migration of many
constituents will be retarded by natural attenuative processes,  sampling
at the periphery of the plume may not identify all the constituents from
the facility that are reaching ground water and the concentration of
waste constituents detected at the periphery of the plume may be
significantly less than in the interior of the plume.  Patterns of
concentration of individual constituents can be established throughout
                                   6-15

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              ——i  WASTE DISPOSAL UNIT BOUNDARY

              	  CONTAMINANT PLUME

              (J?)  DETECTION SYSTEM WELL CLUSTER (CONTAMINATED)

              X  ASSESSMENT WELL CLUSTER (INITAIL)

              - -  FUTURE TRANSECTS OF THE PLUME (USED TO LOCATE WELL CLUSTERS
                  FOR FUTURE PLUME CHARACTERIZATION)

              X  UP GRADIENT WELL CLUSTER
FIGURE 6-2.  INITIAL PLACEMENT OF WELL CLUSTERS TO DEFINE THE EXTENT OF
             CONTAMINATION IN THE HORIZONTAL PLANE
                                  6-16

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the plume by sampling along several lines that perpendicularly transect
the plume.  The number of transects and spacing between sampling points
should be based on the size of the plume and variability in geology
observed at the site.  Sampling locations should also be selected so as
to identify those areas of maximum contamination within the plume.  In
addition to the expected contaminants, the plume may contain constituent
degradation products as well as reaction products.
     6.5.3  Sampling Depths
     The owner/operator should specify in the assessment plan the depth
at which samples will be taken at each of the planned sampling locations.
These sampling depths should be sufficient to profile the vertical distri-
bution of hazardous waste constituents at the site.  Vertical sampling
should identify the full extent of vertical constituent migration.
Vertical concentration gradients including maximum concentration of each
hazardous waste constituent in the subsurface should similarly be
identified.  The amount of vertical sampling required at a specific site
will depend on the thickness of the plume and the vertical variability
observed in the geology of the site.  All potential migration pathways
should be sampled.  The sampling program should clearly bound the
vertical extent of migration by identifying those areas on the periphery
of the plume that have not been contaminated.
     In order to establish vertical concentration gradients of hazardous
waste constituents in the plume, the owner/operator must obtain a
continuous sample of the plume, which means well clusters should be
employed.  The owner/operator, however, cannot know the vertical extent
of the plume; therefore, the first well in the cluster should be screened
at the horizon contamination was discovered, bearing in mind the 10-foot
screen length guidance.  Additional wells in the cluster should be
screened, where appropriate, above and below the initial well's sampling
interval until the margins of the plume are established.  In general,
five wells per cluster are suggested, three within the plume and one each
                                   6-17

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above and below its vertical margins.  Care must be taken in placing
contiguously screened wells close together since one's drawdown may
influence the next and thus change the horizon from which its samples are
drawn.  Alternation of lower and higher screens should reduce this effect
(see Figure 6-3).
     The specifications of sampling depths included in assessment plans
should clearly identify the interval over which each sample will be
taken.  It is important that these sampling intervals be sufficiently
discrete to permit vertical profiling of constituent concentrations in
ground water at each sampling location.  Sampling will only provide
measurements of the average contaminant concentration over the interval
from which that sample is taken.  Samples taken from wells screened over
a large interval will be subject to dilution effects from uncontaminated
ground water lying outside the plume limits.  Except for certain condi-
tions described in Chapter Two, the screened interval should be kept at
a maximum of ten feet, and in cases in which small vertical concentration
gradients are expected, smaller sampling intervals are appropriate.
     A series of five wells per cluster is suggested to completely
profile the vertical boundaries of the plume.  This will also enable the
identification of vertical concentration gradients and maximum
concentrations of contaminants.
     As part of the progressive assessment monitoring program, the
owner/operator can use geophysical techniques to help verify the adequacy
of the placement of his assessment monitoring network.  Adjustments to
the assessment monitoring program may be needed to reflect plume
migration and changes in direction.
     6.6  Description of Monitoring Well Design And Construction
     The monitoring well design and construction requirements for
assessment monitoring well networks are equivalent to the detection
requirements presented in Chapter Three.
                                   6-18

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WELL
CLUSTER
NO. 1
A D8 E C
r
V
1 ^x

•IIHIIIIItMllllQI
•
" — — _ — 7Q'r-




tl

•

1

M
I
10'

•
•
1
•

II

^



s*'
1 1 1 1 1 1 1 1 • • ijj^i1 •
^^ ^*
CONTA
PL


•10' <--.
i r»'
                                    WASTE
                                   DISPOSAL
                                     UNIT

                                          GROUND-WATER
                                             FLOW
                                            LEGEND
                                            WELL AND SCREEN
                                        10'   SCREEN LENGTH
                                       IIIIH'WATER TABLE
FIGURE 6-3. VERTICAL WELL CLUSTER PLACEMENT
                      6-19

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     6.7  Description of Sampling and Analysis Procedures
     The owner/operator's sampling and analysis plan should be updated to
reflect the different analytical requirements of assessment monitoring.
Otherwise, the sampling and analysis plan used by the owner/operator in
his detection monitoring program (see Chapter Four) should suffice for
assessment monitoring.
     The assessment plan should identify the parameters the owner/
operator will monitor for and should describe why these parameters are
suitable for determining the presence and concentration of hazardous
waste or hazardous waste constituents migrating from the facility in the
ground water.  At a minimum, the owner/operator's assessment plan should
include monitoring for all hazardous waste constituents that are in the
facility's waste.  Hazardous waste constituents, as defined in §260.10,
include all constituents listed in Appendix VII of Part 261, all
constituents included in Table 1 of §261.24, and any constituent listed
in Section 261.33.
     Facilities that are seeking an operating permit, also have
additional plume characterization responsibilities pursuant to Part 270.
Section 270.14(c)(4) requires permit applicants to expand their
monitoring from hazardus waste constituents (primarily Appendix VII) to
the full complement of Appendix VIII constituents (Note:  Appendix VII is
a subset of Appendix VIII).  Therefore, when a unit is subject to the
Part 270 requirements (either because they are seeking an operating
permit or because the Agency has called in their post-closure permit),
the Agency recommends that an owner/operator's assessment plan includes
parameters that will satisfy the requirements of both Part 265 and
Part 270.
     Figure 6-4 illustrates in greater detail the sampling protocol that
the Agency recommends for units that are subject to both Part 265 and
Part 270.  First, the owner/operator should perform an Appendix VIII scan
€
                                   6-20

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                       IDENTIFY HAZARDOUS
                        CONSTITUENTS IN
                       TRIGGERING WELLS
                       (APPENDIX VIII SCAN)
              SELECT HAZARDOUS CONSTITUENTS USEFUL
               IN DETERMINING RATE OF CONTAMINANT
              MIGRATION AND VERTICAL AND HORIZONTAL
                EXTENT OF CONTAMINANT MIGRATION
               CONDUCT SAMPLING EFFORT DESCRIBED IN
               ASSESSMENT PLAN, ESTABLISH GEOMETRIC
               OF CONTAMINANT PLUME(S) AND RATE OF
               MIGRATION OF SELECTED CONSTITUENTS
               CONDUCT SAMPLING EFFORT DESCRIBED IN
             ASSESSMENT PLAN; ESTABLISH VERTICAL AND
              HORIZONTAL CONCENTRATION GRADIENTS OF
          HAZARDOUS CONSTITUENTS IN CONTAMINANT PLUME(S)
FIGURE  6-4.  SELECTION OF PLUME CHARACTERIZATION PARAMETERS
            FOR UNITS SUBJECT TO PART 265 AND PART 270
                               6-21

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of samples from triggering detection monitoring wells.  This scan will
provide the owner/operator with a list of hazardous constituents in the
wells which may be migrating into the uppermost aquifer.  The
owner/operator should select constituents for inclusion in a sampling
program to establish geometric dimensions of the contaminant plume(s) and
the rate of migration of the plume(s).  Once the owner/operator has
established the geometric dimensions of the contaminant plume(s), he
should sample for additional Appendix VIII constituents to establish
vertical and horizontal concentration gradients in the plume(s).
     6.8  Procedures for Evaluating assessment Monitoring Data
     The assessment plan must stipulate and document procedures for the
evaluation of assessment monitoring data.  These procedures vary in a
site-specific manner but must all result in determinations of the rate of
migration, extent, and hazardous constituent composition of the contami-
nant plume.  In some cases, where the release is obvious and/or chemically
simple, it may be possible to characterize it readily from a descriptive
presentation of concentrations found in monitoring wells and geophysical
characterization.  In other cases, where contamination is less obvious or
the release is chemically complex, the owner/operator should employ a
statistical inference approach.  Owner/operators should plan initially to
take a descriptive approach to data analysis in order to broadly delineate
the extent of contamination.  Statistical comparisons of assessment moni-
toring data between wells and/or over time may subsequently be necessary
should the descriptive approach provide no clear resolution of the rate
of migration, extent, and hazardous constituent composition of the
release.
     The objective of assessment monitoring is to estimate the rate and
extent of migration and the concentration of constituents in the plume.
Data are therefore collected from a set of assessment monitoring wells
that will allow characterization of the dimensions and concentrations of
€
                                   6-22

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ground-water constituents (GWCCs) in the plume.  In addition, compared to
detection monitoring, the number of chemical species that are analyzed in
assessment increases.  Because the amount of data collected in assessment
is more voluminous than detection monitoring, the methods used to analyze
assessment monitoring data emphasize organization, data reduction,
simplification, and summary.
     Assessment monitoring will include the measurement of many more
GWCC in a more extensive well network than detection monitoring.  These
requirements necessitate the collection of large amounts of data during
the assessment monitoring program.  Consequently, it is extremely
important for the enforcement officer to make sure that the owner/
operators specify in their assessment plans the data evaluation
procedures required by 265.93(d)(3)(iii).
     Specific evaluation and reporting procedures are presented below
which the owner/operator should follow when recording and evaluating
assessment monitoring data.  These procedures are used to structure,
analyze, simplify and present the ground-water monitoring data to help
the enforcement officer evaluate the extent and concentration of
ground-water contaminants.  There are four evaluations or reporting
procedures that should be described in the assessment plan and that
should be used to record data in the on-site archives required by
265.94(b):
     •  Listing of Data
     •  Summary Statistics Tables
     •  Data Simplification
     •  Plotting of Data
     6.8.1   Listing of the Data
     A list of all the detection monitoring data and the assessment
monitoring data that have been collected should be available to
                                   6-23

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enforcement officers when they review on-site records.  First, data as
originally reported and verified by the analytical laboratory for those
measures requiring laboratory evaluation or as recorded in the field for
those measures collected at the time of sampling should be available to
the enforcement officer.  These reporting forms should include informa-
tion which indicates that quality control samples (e.g., field and filter
blanks) were obtained in the field.  Also the laboratory reporting should
indicate that both the field quality control samples were analyzed and
that the laboratory has performed and reported standard quality control
procedures performed in the laboratory (e.g., recovery analyses,
analytical replicates etc.).
     The listing of GWCC concentration data should follow a format
similar to Table 6-1.  The variables which should be included in the
listing are codes that identify the GWCC, well, date, unit of measure,
whether the value was LT a limit of detection and the concentration of
the GWCC.  Also the listing should include the results of and codes
identifying the quality control analyses that were performed.  GWCC
concentrations measured as LT a limit of detection should be indicated
and if possible the GWCC concentration that was measured should be
reported with the LT designation.  Otherwise, the value that accompanies
the LT designation should be the accepted detection limit for the method
that was used.  Documentation that describes the meaning of the codes
used in the listing is required to eliminate ambiguity (e.g.  Pb=lead,
ppm=parts per million).  The listing of GWCC data must include all
measurements from all wells since  the facility began sampling, including
samples obtained during detection monitoring.
     The listing should be organized to allow quick reference to specific
data values.  One categorization would be to first group by GWCC, then
well code, and finally the date, as shown in Table 6-1.  For example, all
lead measurements should be together, followed by all chromium measure-
ments, etc.  The values for each GWCC from one well should be grouped and
f
                                   6-24

-------
                                               TABLE 6-1
                    AN EXAMPLE  OF  HOW ASSESSMENT MONITORING DATA SHOULD BE LISTED
GUCC
                           WELL
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD IUG/L)
LEAD (UG/L)
LEAD (UG/L)
LEAD (UG/L)
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLEHE
TRICHLOROETHYLEHE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE
TRICHLOROETHYLENE

















( UG/L )
I UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
( UG/L I
( UG/L I
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
( UG/L )
(UG/L)
(UG/L)
( UG/L )
( UG/L 1
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
(UG/L)
( UG/L )
( UG/L )
(UG/L)
( UG/L )
( UG/L )
I IBM
7A
7A
7A
7A
7A
9A
9A
9A
9A
9A
98
9B
9B
98
9B
9B
98
1A
U
1A
1A
1A
1A
1A
1A
1A
U
1A
10A
10A
10A
10A
10A
10A
10A
10A
10A
IDA
IDA
10A
10A
10A
10A
10A
10B
10B
10B
10B
108
10B
10B
10B
io-t
REPLICATE

    1
    1
    1
    Z
    Z
    1
    1
    Z
    1
    Z
    I
    1
    Z
    1
    Z
                                               ALIQUOT
                                                          DATE
                                                                    LT DETECTION
                                                                                    CONCENTRATION    UNITS
A
A
B
A
B
A
B
A
A
A
A
B
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B
A
A
A
A
A
A
A
A
A
A
A
B
A
B
A
B
A
A
A
A
A
A
A
A
12JAN85
17FEB85
17FEB85
17FEB85
17FEB85
26APR84
26APR84
26APR84
05MAY84
05MAY84
26APR84
26APR84
26APR84
05MAY84
05MAY84
15JUN84
15JUL84
26APR84
05MAY64
15JUN84
15JUL64
15AUG84
15SEP84
160CT84
18NOV84
20DEC84
12JAN85
17FEB85
26APR84
26APR84
26APR84
05HAY84
05MAY84
1SJUN84
15AUG84
15SEP84
160CT84
18NOV84
20DEC84
12JAN85
17FEB85
17FEB8S
17FEB85
17FEB85
26APR84
26APR84
26APR84
05MAY64
05MAY84
15JUN84
15JUL84
15AUG84
t^
4
29.62
28.43
28.29
23.17
28.30
10.00
10.00
20.60
21.20
21.60
67.20
67.80
64.10
38.90
39.60
57.22
20.12
10.00
10.00
10.00
11.10
10.00
10.10
10.70
10.00
10.00
10.00
10.00
17.00
17.30
17.60
21.00
21.40
Z1.20
22.90
19.40
19.60
30.10
31.60
33.60
27.80
27.80
26.40
26.50
65.10
65.80
65.40
84.00
83.70
69.00
68.40
93.40
8:28
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
PPB
                                                  6-25

-------
ordered by date followed by the data from the next well and so on for all
wells in the ground-water monitoring system.  Alternate sortings of the
data listing may also be useful to the enforcement officer.
     The data listing is not intended to function alone as an analytic
tool but the enforcement officer can use the data listing to assist in
the review of the GWCC data.  First, the ordered list of data will allow
the enforcement officer quick reference to every GWCC concentration
measurement if. for example, a spurious result was found in a supporting
data analysis or report.  Also, the enforcement officer can, by requiring
a consistent and orderly data listing, encourage the owner/operator to
correct many of the data quality problems, which occur frequently on
"raw" laboratory reporting sheets.  Finally, data can be placed more
easily onto a State or regional computer if the data are organized and
reported consistently in a listing rather than on laboratory reporting
sheets which may have only the sample number identification rather than
well codes, dates of sampling, etc.
     6.8.2   Summary Statistics Tables
     The ground-water monitoring data should be summarized and presented
in tabular formats.  Eight summary statistics should be calculated and
used in each of four summary tables.  The eight summary statistics are:
     •  Number of LT detection limit values
     •  Total number of values
     •  Mean
     •  Median
     •  Standard deviation
     •  Coefficient of variation
     •  Minimum value
     •  Maximum value
The methodology used to estimate  these summary statistics can be  found in
many statistical textbooks.
                                   6-26

-------
     The four tables of summary statistics should include summaries by:
     •  GWCC summary (e.g., Table 6-2)
     •  GWCC summary by well (e.g., Table 6-3)
     •  GWCC summary by well and date (e.g., Table 6-4)
     •  quality control data
     The tables should be formatted so that there are from one to three
columns on the left side of each table which provide data identifying,
where applicable, the GWCC, well, and date.  Eight columns, one for each
summary statistic, should be to the right of the identifying columns.
There will be one row for each category that is being summarized.  A
summary statistics table by GWCC, for example, will have a number of rows
equal to the number of GWCC that have been sampled.  The GWCC-well table
will have a number of rows which equals the number of GWCCs measured
times the number of wells in the monitoring system (provided that each
GWCC was measured at least once in each well).  The GWCC-well-date table
will be the largest table and each row should be prefixed with a GWCC,
well, and date code.  The statistics in the GWCC-well-date table should
summarize all replicate sampling that was performed for each GWCC, from
each well, during each sampling.
     The sample sizes, ranges, minimum, and maximum values will provide a
rapid means for checking whether errors appear in the data.  It will also
facilitate rapid evaluation of GWCC concentrations over the entire
ground-water monitoring system.  In addition, the summary statistics will
allow evaluation of spatial change in GWCC concentrations which include
identifying the rate and extent of migration of the GWCC plume.
     The quality control data should be provided whenever assessment
monitoring data are submitted by an owner/operator.  The quality control
data can be submitted in the format they are received from the laboratory
provided that all data are clearly documented.  The quality control
samples taken in the field (e.g., field and sampling equipment blanks)
                                   6-27

-------
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may not be identified when the samples are supplied to the laboratory,
but should be identified in assessment monitoring data submissions.
Owner/operators should ensure that the laboratories provide the quality
control data that accompanies the data resulting from the analysis of
field samples.
     6.8.3  Data Simplification
     Ranking procedures which are described in this section are useful
for simplifying and interpreting spatial trends in GWCC concentrations by
allowing rapid determination of which wells have the overall highest and
lowest GWCC concentration.  Table 6-5 presents an example of a data set
analyzed by a ranking procedure.
     The ranking can be performed using the mean, median, maximum, or
minimum concentration values in the summary statistics table which
describes the values from each GWCC-well combination.  For example, the
mean concentration from each well is ranked from lowest to highest for
each GWCC.  The well with the lowest mean concentration of a GWCC will
receive a value of 1; the well with the next highest concentration of the
same GWCC will receive a value of 2, and so on.  If two or more wells
have the identical mean concentration then the ranks for these wells will
be averaged and applied to all wells with the same mean concentration.
This procedure should be repeated for each GWCC which was detected at
least once at every well in the monitoring system.  The pH values may be
ranked from highest to lowest rather than from lowest to highest
depending on whether the ground-water contamination is likely to result
in an increase or decrease in pH.  It is also useful to calculate an
overall average rank for each well by averaging the ranks for each GWCC
associated with the well.  These ranks should be presented in a table
using GWCCs as column headings and well codes as row headings.  It is
advisable to group GWCCs with similar chemistry (e.g., volatile organics,
metals, salts, etc.) and order the rows based on the wells with spacial
                                   6-31

-------
                               TABLE 6-5
      AN EXAMPLE OF HOW RANKS OF THE MEAN CONCENTRATIONS FOR EACH
GWCC/WELL COMBINATION CAN BE USED TO SIMPLIFY AND PRESENT CONCENTRATION
 DATA COLLECTED FOR A VARIETY OF QWCCs IN A NUMBER OF MONITORING WELLS
WELL RANK OF MEAN
CHROMIUM
CONCENTRATION
17A
2A
4A
11A
3A
9A
1A
98
ISA
13A
10A
14A
7A
1ZA
16A
10B
3
3
3
5
1
6
2
4
8
7
12
9
11
14
10
13
RANK OF MEAN
LEAD
CONCENTRATION
3
3
3
3
6
3
8
7
9
12
10
16
11
15
14
13
RANK OF MEAN
TCE
CONCENTRATION
1
•
•
4
2
5
3
12
6
10
11
7
9
a
1<4
13
RANK OF MEAN
MC
CONCENTRATION
3
•

3
6
3
7
8
11
9
10
12
15
14
13
16
AVERAGE WELL
RANK ACROSS
GWCC
2.50
3.00
3.00
3.75
3.75
4.25
5.00
7.75
8.50
9.50
10.75
11.00
11.50
12.75
12.75
13.75
                               6-32

-------
proximity (e.g., upgradient, downgradient in plume, downgradient out of
plume, shallow screen depth).  This will facilitate identification of
specific groups of wells where high concentrations of GWCC were detected.
     6.8.4  Graphic Displays of Data
     6.8.4.1  Plotting Data Over Time
     Ground-water data should be plotted to allow evaluation of temporal
changes in GWCC concentrations over time.  Each plot should consist of a
X or horizontal axis which represents time with year and month identified
at intervals.  The Y or vertical axis should represent the concentrations
of GWCCs.  The plots may be constructed using the mean values from the
GWCC-well-date summary statistics table and one plot could be presented
for each GWCC/well combination as in Figure 6-5.  Alternately, it may be
more insightful to plot the data from several wells or GWCCs on one graph
provided the lines do not overlap excessively as in Figure 6-6.
     Data plotting will allow the enforcement officer to evaluate changes
in GWCC concentration over time that might be due to surface hydrological
events, hydrogeology, or facility releases.  In addition, insights
regarding geochemical interactions may also be revealed by examining
whether changes in some GWCCs result in expected changes in other GWCCs.
     6.8.4.2  Plotting Data on Maps
     It may also be useful to plot data on facility maps so that trends
in GWCCs both vertically and horizontally can be evaluated.  The summary
statistics from the GWCC-well table can be used to provide data for
plotting.  A map of the facility, which identifies well locations, should
be used to depict horizontal trends in concentrations.  Geological cross
sections and/or facility map may be usefulfor plotting vertical trends in
GWCC concentrations.  The mean concentrations can be placed near each
well location similar to the construction of potentiometric maps described
in earlier chapters.  It may also be useful to plot isopleth contours of
concentration on the maps.
                                   6-33

-------
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                                             6-35

-------
     6.9  Rate of Migration
     An assessment plan should specify the procedures the owner/operator
will use to determine the rate of constituent migration in ground water.
A rapid approach will generally be required for determining the rate of
migration during interim status assessments.  Migration rates can be
determined by monitoring the concentration of GWCCs over a period of time
in monitoring wells aligned in the direction of flow.  If these wells are
located both at the edge of the plume and in the interior of the plume,
subsequent analysis of the monitoring data can then provide an accurate
determination of the rate of migration both of the contaminant front as a
whole and of individual constituents within the plume.  This approach
does not necessarily provide a reliable determination of the migration
rates that will occur as the contaminant plume continues to move away
from the facility in light of potential changes in geohydrologic
conditions.  More importantly, this approach requires the collection of a
time series of data of sufficient duration and frequency to gauge the
movement of contaminants.  Such a delay is normally inappropriate during
initial assessment of ground-water contamination since a relatively quick
determination or at least an estimate of migration rates is required to
deduce the impact of ground-water contamination and to formulate an
appropriate reaction.  Estimates of migration rates can be obtained from
aquifer properties obtained during the site investigation, and knowledge
of the physico-chemical properties of contaminants known to be present.
By recognizing the various factors which can effect transport processes
of the GWCCs, the owner/operator can obtain approximate potential
migration rates during an initial assessment phase.  Continued monitoring
of the plume to verify rates of migration during assessment monitoring
established at a facility should serve as a basis for identifying
additional monitoring well locations.
     Initial approximations of contaminant migration rates based on
ground-water flow rates are not reliable without verification because of
                                   6-36

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potential differential transport rates among various classes of chemical
constituents.  Differential transport rates are caused by several factors
including:
     •  Dispersion due to diffusion and mechanical mixing
     •  Retardation due to adsorption and electrostatic interactions
     •  Transformation due to physical, chemical, and/or biological
        processes
Dispersion results in the overall dilution of the contaminant; however,
chromatographic separation of the contaminant constituents and
differential dispersal effects can result in a contaminant arriving at a
particular location before the arrival time computed solely on average
ground-water flow rates.  Alternately, retardation processes can delay
the arrival of contaminants beyond that calculated by the average
ground-water flow rates.  Local geology will also affect constituent
migration rates.  Relating constituent migration rates to ground-water
flow rates is appropriate for a quick approximation during the initial
assessment phase, but this should be followed by a more comprehensive
study of migration rates.
     Simple slug tests are not the preferred method for determining the
rate of contaminant migration.  The slug test is limited to the immediate
vicinity where it is performed and its results often cannot be projected
across an entire site.
     At those facilities where sufficient immiscible contaminants have
leaked to form and migrate as a separate immiscible phase (see
Figure 6-7), additional analysis will be necessary to evaluate the
migration of these contaminants away from the facility.  Chapter Five
contains a discussion of the ground-water monitoring techniques that can
be used to sample multi-phased contamination.  The formation of separate
phases of immiscible contaminants in the subsurface is largely controlled
                                   6-37

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                          6-38

-------
by the rate of infiltration of the immiscible contaminant and the
solubility of that contaminant in ground water,  immiscible contaminants
generally have some limited solubility in water.  Thus, some amount of
immiscible contaminant leaking from the facility will enter into solution
in groundwater and migrate away from the facility as dissolved
constituents.  However, if the amount of immiscible reaching ground water
exceeds the ability of ground water to dissolve it, the ground water in
the upper portion of the water-table aquifer will become saturated and
the contaminant will form a separate immiscible phase.
     At this point the behavior and migration of the contaminants present
in the immiscible phase will be strongly influenced by its density
relative to ground water.  If the immiscibles are less dense than ground
water, the immiscibles will tend to coalesce on the surface of the water
table and form and migrate as a separate immiscible layer floating on
ground water.  If the density of the immiscible contaminants is similar
to that of ground water, the immiscible will tend to mix and flow as a
separate phase with the ground water, creating a condition of multiphase
flow.
     If the density of the immiscibles is greater than ground water, the
immiscibles will tend to sink in the aquifer (see Figure 6-7).  As the
immiscibles sink and reach unaffected ground water in a deeper portion of
the aquifer, more of the immiscible contaminant will tend to enter into
solution in ground water and begin to migrate as dissolved constituents.
However, if enough of the dense immiscible contaminants are present, some
portion of these contaminants will continue to sink as a separate
immiscible phase until a formation of reduced permeability is reached.
At this point, these contaminants will tend to coalesce and migrate as a
layer of dense immiscibles resting on the geologic barrier.
     In each of these cases, the contaminants present in the separate
immiscible phase may migrate away from the facility at rates different
                                   6-39

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than that of ground water.  In many cases, they will migrate at rates
slower than or equivalent to ground water, but in some cases migration
rates can be greater.  In addition, migration of the immiscibles may not
be in the direction of ground-water flow.  However, it is important to
reemphasize that some amount of these contaminants will invariably
dissolve in ground water and migrate away from the facility as dissolved
constituents.
     Light immiscible contaminants will migrate downgradient to form a
floating layer above the saturated zone (see Figure 6-7).  The slope of
the water table and the direction of ground-water flow will dictate the
movement of this light immiscible layer.  Important factors involved in
its migration rate include the intrinsic permeability of the medium and
the density and viscosity of the contaminants.  With time, an ellipsoidal
plume develops overlying the saturated zone as depicted in Figure 6-7.
While it is possible to analyze the behavior of the light immiscible
layer using analytical or numerical models, the most practical approach
for determining the rate and direction of migration of such a light
immiscible layer during an assessment may be to observe its behavior over
time with appropriately located monitoring wells.
     The migration of a layer of dense immiscibles resting on a confining
layer may be strongly influenced by gravity.  Depending on the slope of
the confining layer, the immiscible layer may move with or against the
flow of ground water.  Consequently, the evaluation of the rate and
direction of migration of a dense immiscible layer is best determined by
clearly identifying the configuration of the barrier on which the layer
is migrating.  The direction of migration and estimates of migration
rates can then be obtained by including the gravitational forces induced
by the slope of the confining layer in the gradients used to calculate
flow rates.  A program of continued monitoring of the dense immiscible
layer should always be included in the assessment plan to verify
direction and rate of flow.
                                   6-40

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     6.10  Reviewing Schedule Of Implementation
     The assessment plan should specify a schedule of implementation.
When reviewing schedules the particulars of each assessment program will
have to be considered, including the amount of work involved in the
assessment and other local factors such as weather and availability of
equipment and personnel.  The schedule should include a sufficient number
of milestones so that the Agency can Judge whether sufficient progress is
being made toward the completion of the assessment during its
implementation.  Any continued monitoring undertaken during the
maintenance phase of assessment should be scheduled at least on a
quarterly basis.
     Activities planned to initially determine if contamination has
actually occurred should not unnecessarily delay the implementation of a
comprehensive assessment.  When an extensive program to collect additional
data to remedy inadequacies in currently available data is to be under-
taken these activities should require only a short period for completion.
Additional analysis of water quality data should require no more than
fifteen days to thirty days.  Sampling to determine actual concentrations
of HWC's should require only time enough for sample collection and
analysis followed by a brief period for subsequent analysis of the data.
     A thorough discussion of monitoring well placement, and monitoring
well design and construction can be found in Chapters Two and Three,
respectively.  A discussion of the ground-water monitoring techniques
necessary to effectively characterize a multi-phase containment migration
is also given in Chapter Four of this document.
                                   6-41

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GLOSSARY

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                                 GLOSSARY
Annular Space - The open space formed between the borehole and the well
casing.

Anticline - A fold, usually from 100 meters to 300 kilometers in width,
that is convex upward with the oldest strata at the center.

Appendix VIII Constituents - A list of 297 toxic constituents (§Part 261)
which if present in a waste may make the waste hazardous if the waste
poses a substantial hazard to human health or the environment when
improperly treated, stored, transported or disposed.

Aquiclude - A geologic formation which may contain ground water but is
incapable of transmitting significant quantitites under normal hydraulic
gradients.

Aquitard - A geologic formation of low permeability which can store or
transmit ground water in significant quantities but typically at a very
slow rate.

Assessment Monitoring - A program of monitoring under interim status
after a release to ground water has been determined wherein the rate of
migration extent and hazardous constituent concentration gradients of the
contamination must be identified.

Assessment Plan - The written detailed plan drawn up by an owner/operator
which describes and explains the procedures the owner/operator intends to
take to perform assessment monitoring.

Background Concentrations - A schedule of sampling and analysis that is
completed during the first year of monitoring.  All wells in the
monitoring system must be sampled on a quarterly basis for the drinking
water suitability, ground-water quality, and contamination indicator
parameters.  For each upgradient well, at least four replicate
measurements must be made for the contamination indicator parameters.
These replicate measurements must be posted and the initial background
arithmetric mean and variance calculated.

Basement - The oldest rocks recognized in a given area, a complex of
metamorphic and igneous rocks that underlies all the sedimentary
formations.

Bentonite - A sedimentary rock largely comprised of clay minerals that
have a great ability to absorb water and swell in volume.
                                   G-l

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Borehole Geophysics  (Geophysical Borehole Logging) - A general terra that
encompasses all techniques in which a sensing device is lowered into a
borehole for the purpose of characterizing the associated geologic
formations and their fluids.  The results can be interpreted to determine
lithology, geometry  resistivity, bulk density, porosity, permeability,
and moisture content and to define the source, movement, and physical/
chemical characteristics of ground water.

Coefficient of Variation - The standard deviation divided by the mean of
a set of data.  (Note:  the coefficient of variation can be expressed as
a percentage by multiplying the number obtained by 100).

Confined Aquifer - An aquifer under greater than atmospheric pressure
bounded above and below by impermeable layer or layers of distinctly
lower permeability (aquitard) than the aquifer itself.

Confining Layer - A geologic stratum formation exhibiting low
permeability having  little or no intrinsic permeability.

Core - A continuous columnar sample of the lithologic units extracted
from a borehole.   Such a sample preserves stratigraphic contacts and
structural features.

Direct Methods for Hydrogeological Investigations - Methods (e.g,
boreholes and monitoring wells) which entail the excavation or drilling,
collection, observation, and analysis of geologic materials and water
samples.

Dispersivity - Ability of a contaminant to disperse within the ground
water due to molecular diffusion and mechanical mixing.

Disposal Facility - A facility or part of a facility complex at which
hazardous waste is intentionally placed into or on any land or water,
and at which waste will remain after closure of the facility.

Downgradient - Direction of decreasing hydrostatic pressure.

Downgradient Well - A well which has been installed hydraulically
downgradient of the site,  and is capable of detecting the migration of
contaminants from a regulated facility.  Regulations require the
installation of three or more downgradient wells depending upon the site-
specific hydrogeological conditions and potential zones of contaminant
migration.

Drilling Mud - Fluids which are used during the drilling of a borehole or
well to wash soil  uttings away from the drill bit and adjust the
specific gravity oc the liquid in the borehole so that the sides of the
hole do not cave in prior to installation of a casing.
                                    G-2

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Electrical Resistivity  (ER) - A surficial geophysical method whereby
known current is applied to spaced electrodes in the ground and  the
resulting electrical resistance used to detect changes in earth  materials
between and below the electrodes.  ER is particularly useful for
facilities receiving electrically conductive wastes (e.g., inorganic) at
sites characterized by  settings having minimal quantities of high
resistance materials.

Electromagnetic Conductivity (EM) - A surficial geophysical method
whereby induced currents are produced and measured in conductive
formations from electromagnetic waves generated at the surface.  EM is
used to define shallow  ground water zones characterized by high  dissolved
solids content.

Floaters - Light phase  organic liquids in ground water capable of forming
an immiscible layer which can float on the water table.

Flow Net - A set of intersecting equipotential lines and flow lines
representing a two-dimensional steady flow through porous media.

Fluvio-Glacial Depositional Environment - A complex melange of glacially
borne and riverine sediments deposited at the head of a melting  glacier.
The sediments range in  grain size from clays to boulders, and in places
are typically unsorted.

Geophysical Borehole Logging - See Borehole Geophysics.

Ground Penetrating Radar (GPR) - A geophysical method used to identify
surface formations which will reflect electromagnetic radiation.   GPR
is useful for defining  the boundaries of buried trenches and other
subsurface installations on the basis of time-domain reflectrometry.

Ground-Water Detection Monitoring Program - A monitoring well system
capable of yielding groundwater samples for analysis.  Upgradient wells
must be installed to obtain representative background ground-water
quality in the uppermost aquifer and be unaffected by the facility.
Downgradient wells must be placed immediately adjacent to the hazardous
waste management area(s) to detect hazardous waste or hazardous waste
constituents migrating from the facility.

Hazardous Waste Constituent - A constituent listed as hazardous by EPA
based upon the criteria cited in Part 261, Subpart D,  or a constituent
listed in Table 1 of §261.24.

Hazardous Waste Management - The systematic control of the collection,
source separation,  storage, transportation,  processing, treatment,
recovery,  and disposal of hazardous waste.
                                   G-3

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Hazardous Waste Management Area - The area within a facility's property
boundary which encompasses one or more hazardous waste management units
or cells.  Detection monitoring wells should be placed on the immediate
perimeter of this area and spaced based upon the site-specific
hydrogeological characteristics.

Hydraulic Conductivity - A coefficient of proportionality which describes
the rate at which a fluid can move through a permeable medium.  It is a
function of the media and of the fluid flowing through it.

Indicator Parameters - pH, specific conductance, total organic carbon
(TOC), total organic halogens (TOX).

Indirect Methods for Hydrogeological Investigations - Methods which
include the measurement or remote sensing of various physical and/or
chemical properties of the earth (e.g., electromagnetic conductivity,
electrical resistivity, specific conductance, geophysical logging, aerial
photography).

Intrinsic Permeability - Relates to the relative ease of a porous medium
to transmit liquid under a hydraulic gradient, and is independent of the
liquid itself.

Ion Exchange Capacity - Measured ability of a formation to adsorb charged
atoms or molecules.

Karst Topography - A topographic area which has been created by the
dissolution of a carbonate rock terrain.  This type of topography is
characterized by sinkholes, caverns, and lack of surface streams.

Landfill - A disposal facility or part of a facility where hazardous
waste is placed in or on the land and which is not a land treatment
facility, a surface impoundment, or an injection well.  A landfill should
not be used to store materials containing free liquids.

Leachate - A liquid including any suspended components in the liquid that
has percolated through or drained from hazardous waste.

Less Than Detection Limits - A phrase meaning that a chemical constituent
was either not identified or not quantified at the lowest level of
sensitivity of the analytical method being employed by the laboratory.
Therefore, the chemical constituent either is not present in the sample,
or is present but in such a small concentration it could not be measured
by the analytical procedure.
                                    G-4

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Liner - A continuous  layer of natural or man-made materials beneath or on
the sides of a surface impoundment,  landfill, or  landfill cell, which
restricts the downward or lateral escape of hazardous waste, hazardous
waste constituents, or leachate.

Litholoqy - The systematic description of rocks,  in terms of mineral
composition and texture.

Maximum Value - In a  set of data, the measurement having the highest
numerical value.

Mean - The sum of all measurements collected over a statistically
significant period of time (e.g., one year) divided by the number of
measurements.

Median - The middle point in a set of measurements ranked by numerical
value.  If there are  an even number  of measurements, the medium is the
mean of the two central measurements.

Minimum Value - In a  set of data, the measurement having the lowest
numerical value.

Mounding - A phenomenon usually created by the recharge of ground water
from a manmade structure into a permeable geologic material.  Associated
ground-water flow will be away from  the manmade structure in all
directions.

Number of LT Dtection Limit Values - The number of times a chemical
parameter was not detected by a given analytical procedure over a
statistically significant period of  time (e.g., one year).

Octanol-Water Partition Coefficient  - A coefficient representing the
ratio of solubility of a compound in octanol to its solubility in water.
As the octanol-water partition coefficient increases, water solubility
decreases.

PVC - Polyvinyl chloride.

Petrographic Analysis - Systematic description and classification of
rocks.

Phreatic Zone - See Saturated Zone.

Piezometers - Generally a small diameter, non-pumping well used to
measure the elevation of the water table or potentiometric surface.
                                    G-5

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Potentiometrie Surface (Piezometric surface) - The surface that
represents the level to which water from a given aquifer will rise by
hydrostatic pressure.  When the water-bearing zone is the uppermost
unconfined aquifer, the potentionmetric surface is identical to the water
table.

Pump Test - A test made by pumping a well for a period of time and
observing the change in hydraulic head in adjacent wells.  A pump test
may be used to determine degree of hydraulic interconnection between
different water-bearing units as well as the recharge rate of a well.

Qualified Geologist - A professional (e.g., degree, experience, or
certified) specializing in the study of the earth material science.

Regional Administrator - The Regional Administrator of the appropriate
Regional Office of the Environmental Protection Agency, or the authorized
representative.

Regulated Unit - Hazardous waste management unit.  The number of
regulated units will define the extent of the hazardous waste management
area.

Sampling and Analysis Plan - A detailed document describing the
procedures which will be used to collect, handle, and analyze ground-
water samples for detection or assessment monitoring parameters.  The
plan should detail all quality control measures which will be implemented
to ensure sample collection, analysis, and data presentation activities
meet the prescribed requirements.

Saturated Zone (Phreatic Zone) - A subsurface zone below in which the
interstitial space of a porous medium is completely filled with water.

Seismic Prospecting - Any of the various geophysical methods for
characterizing subsurface properties based on the analysis of elastic
waves artificially generated at the surface (e.g., seismic reflection,
seismic refraction).

Shelby Tube or Split Spoon Sampler - Devices used in conjunction with a
drilling rig to obtain an undisturbed core sample of the strata.

Significant Digits - The number of digits reported in the result of a
calculation or measurement (exclusive of following zeroes).

Sinkers - Dense phase organic liquids which coalesce in an immersible
layer at the bottom of the saturated zone.
                                    G-6

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Slug Test - An aquifer  test made by either pouring a small charge of
water into a well or by withdrawing a slug of water from  the well and
monitoring the length of time the well requires to return to static water
level conditions.  This test is often employed to determine hydraulic
conductivity.

Standard Deviation - The positive square root of the variance.   (The
variance is the average of the squares of the differences between the
actual measurements and the mean.)

Surface impoundment - A facility or part of a facility which is  a natural
topographic depression, man-made excavation, or diked area formed
primarily of earthen materials (although it may be lined  with man-made
materials), which is designed to hold an accumulation of  liquid  wastes or
wastes containing free  liquids, and which is not an injection well.
Examples of surface impoundments are holding, storage, settling, and
aeration pits, ponds, and lagoons.

T-Test - The t-test is  a statistical method used to determine the
significance of difference or change between sets of initial background
and subsequent parameter values.

TOG - Total organic carbon (SW-46, Method 9060).

TOX - Total organic halogens (SW-846, Method 9020).

Teflon - Tradename for  polyperfluorethylene.

Total Number of Values  - The number of measurements (including less than
detection values) made  for a chemical parameter over a statistically
significant period of time (e.g., one year).

Tremie Method - Method  whereby bentonite/cement slurries  are pumped
uniformly within the annular space of a well.

Unsaturated Zone - A subsurface zone above the water table in which the
interstices of a porous medium are only partially filled  with water.
Also referred to as Vadose Zone.

Upgradient - Direction of increasing hydrostatic pressure.

Upgradient Well - One or more wells which are placed hydraulically
upgradient of the site and are capable of yielding ground-water samples
that are representative of regional conditions and are not affected by
the regulated facility.
                                   G-7

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Uppermost Aquifer - The geological formation nearest the natural ground
surface that is an aquifer, as well as all lower water-bearing units that
are hydraulically interconnected with it, and overlying or perched water-
bearing zones.

Vadose Zone - See Unsaturated Zone.

Volatile Constituents - Solid or liquid compounds which are relatively
unstable at standard temperature and pressure and undergo spontaneous
phase change to a gaseous state.

Water Table - The water level surface below the ground at which the
vadose zone ends and the phreatic zone begins.  It is the level to which
a well screened in the unconfined aquifer would fill with water.

Well - A shaft or pit dug or bored into the earth, generally of a
cylindrical form, and often walled with tubing or pipe to prevent the
earth from caving in.

Well Cluster - A well cluster consists of two or more wells completed
(screened) to different depths in a single borehole or a series of
boreholes in close proximity to each other.  From these wells, water
samples that are representative of the different horizons within one or
more aquifers can be collected.

Well Evacuation - Process of removing stagnant water from a well prior to
sampling.

X-Ray Diffraction - An analytical technique used to determine the
inorganic constituent content in solid materials.  The sample is exposed
to x-ray radiation and the x-rays are refracted in patterns which are
characteristic of the individual inorganic constituents  (e.g., NaCl).

Zone of Potential Contaminant Migration - Any subsurface formation or
layer which is permeable and would preferentially channel the flow of
contaminants away from a regulated facility.
                                    G-8

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     APPENDIX A




EVALUATION WORKSHEETS

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                                  APPENDIX A.I
                 CHARACTERIZATION OF SITE HYDROGEOLOGY WORKSHEET
     The following worksheets have been designed to assist the enforcement
official in evaluating the program the owner/operator used in characterizing
hydrogeologic conditions at his site.  This series of worksheets has been
compiled to parallel the information presented in Chapter 1 of the TEGD.
I.  Review of Site Hydrogeologic Investigatory Techniques
     A.  Was the site investigation and/or data collection
        performed by a qualified geologist?                           (Y/N)_
     B. Did the owner/operator survey the following existing
        regional data:

        1.  U.S.G.S. Maps?                                            (Y/N).
        2.  Water supply well logs?                                   (Y/N).
        3.  Other (specify) 	
    C.  Did the owner/operator use the following direct
        techniques in the hydrogeologic assessment:

        1.   Soil borings/rock corings?                                (Y/N)_
        2.   Materials tests (e.g., grain size analyses,
            standard penetration tests, etc.)?                        (Y/N)_
        3.   Piezometer installation for water level
            measurements at different depths?                         (Y/N)_
        4.   Slug tests?                                               (Y/N)
        5.   Pump tests?                                               (Y/N)]
        6.   Geochemical analyses of soil samples?                     (Y/N)_
        7.   Other (specify) 	
    D.   Did the owner/operator use the following indirect
        techniques to supplement direct techniques data:

        1.   Geophysical well logs?                                    (Y/N).
        2.   Tracer studies?                                           (Y/N)[
        3.   Resistivity and/or electromagnetic conductance?           (Y/N)
        4.   Seismic Survey?                                           (Y/N)
        5.   Hydraulic conductivity measurements of cores?             (Y/N)
                                   Al-1

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    6.  Aerial photography?
    7.  Ground penetrating radar?
    8.  Other (specify) 	
E.  Did the owner/operator document and present the
    raw data from the site hydrogeologic assessment?

F.  Did the owner/operator document methods (criteria)
    used to correlate and analyze the information?

G.  Did the owner/operator prepare the following:

    1.  Narrative description of geology?
    2.  Geologic cross sections?
    3.  Geologic and soil maps?
    4.  Boring/coring logs?
    5.  Structure contour maps of aquifer and aquitard?
    6.  Narrative description of ground-water flows?
    7.  Water table/potentiometric map?
    8.  Hydrologic cross sections?

H.  Did the owner/operator obtain a regional map of the
    area and delineate the facility?

I.  If yes, does this map illustrate:

    1.  Surficial geology features?
    2.  Streams, rivers, lakes, or wetlands near the facility?
    3.  Discharging or recharging wells near the facility?

J.  Did the owner/operator obtain a regional
    hydrogeologic map?

K.  If yes, does this hydrogeologic map indicate:

    1.  Major areas of recharge/discharge?
    2.  Regional ground-water flow direction?
    3.  Potentiometrie contours which are consistent with
        observed water level elevations?

L.  Did the owner/operator prepare a facility site map?

M.  If yes, does the site map show:

    1.  Regulated units of the facility (e.g., landfill
        areas, impoundments)?
    2.  Any seeps, springs, streams, ponds, or wetlands?
(Y/N).
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N).




(Y/N)
(Y/N).

(Y/N).

(Y/N).
(Y/N)
(Y/N)
                               Al-2

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            Location of monitoring wells,  soil borings,
            or test pits?                                             (Y/N).
            How many regulated units does the facility have?  	
            If more than one regulated unit then,
            •  Does the waste management area encompass all
               regulated units?                                       (Y/N).
               Or
            •  Is a waste management area delineated for each
               regulated unit?                                        (Y/N).
II.   characterization of Subsurface Geology of site

    A.   Soil boring/test pit program:

        1.  Were the soil borings/test pits performed under
            the supervision of a qualified professional?              (Y/N).
        2.  Were the borings placed 300 feet apart?                   (Y/N).
        3.  If not, did the owner/operator provide documentation
            for selecting the spacing for borings?                    (Y/N)_
        4.  Were the borings drilled to the depth of the first
            confining unit below the uppermost zone of
            saturation or ten feet into bedrock?                      (Y/N).
        5.  Indicate the method(s) of drilling:
            •  Auger (hollow or solid stem)                    	
            •  Mud rotary                                      	
            •  Air rotary                                      	
            •  Reverse rotary                                  	
            •  Cable tool                                      	
            •  Jetting                                         	
            •  Other (specify) 	
        6.  Were continuous sample corings taken?                     (Y/N)
        7.  How were the samples obtained (check method[s])
            •  Split spoon                                  	
            •  Shelby tube, or similar                      	
            •  Rock coring                                  	
            •  Ditch sampling                               	
            •  Other (explain)                              	
        8.   Were the continuous sample corings logged by a
            qualified geologist?                                      (Y/N).
        9.   Does the field boring log include the following
            information:
            •  Hole name/number?                                      (Y/N).
            •  Date stared and finished?                              (Y/N)]
            •  Geologist's name?                                      (Y/N)_
                                   Al-3

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           Driller's name?                                        (Y/N).
           Hole location (i.e., map and elevation)?               (Y/N)_
           Drill rig type and bit/auger size?                     (Y/N).
           Gross petrography (e.g., rock type) of
           each geologic unit?                                    (Y/N).
           Gross mineralogy of each geologic unit?                (Y/N).
           Gross structural interpretation of each                (Y/N).
           geologic unit and structural features
           (e.g., fractures, gouge material, solution
           channels, buried streams or valleys,
           identification of depositional material)?              (Y/N).
           Development of soil zones and vertical extent
           and description of soil type?                          (Y/N).
           Depth of water bearing unit(s) and vertical
           extent of each?                                        (Y/N).
           Depth and reason for termination of borehole?          (Y/N)
           Depth and location of any contaminant encountered
           in borehole?                                           (Y/N).
           Sample location/number?                                (Y/N).
           Percent sample recovery?                               (Y/N).
           Narrative descriptions of:
           — Geologic observations?                              (Y/N).
           -- Drilling observations?                              (Y/N).
    10. Were the following analytical tests performed on the
        core samples:
        •  Mineralogy (e.g., microscopic tests and x-ray
           diffraction)?                                          (Y/N).
        •  Petrographic analysis:
           - degree of crystallinity and cementation of
             matrix?                                              (Y/N).
          - degree of sorting,  size fraction (i.e.
             sieving),  textural variations?                       (Y/N)_
           - rock type(s)?                                        (Y/N)_
           - soil type?                                           (Y/N)_
           - approximate bulk geochemistry?                       (Y/N)
           - existence of microstructures that may effect
             or indicate fluid flow?                              (Y/N)_

           Falling head tests?                                    (Y/N).
           Static head tests?                                     (Y/N).
           Settling measurements?                                 (Y/N).
           Centrifuge tests?                                      (Y/N)_
           Column drawings?                                       (Y/N)_

B.  Verification of subsurface geological data

    1.  Has the owner/operator used indirect geophysical methods
        to supplement geological conditions between borehole
        locations?                                                (Y/N)
                               Al-4

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    2.  Does the number of borings and analytical data indicate
        that the confining layer displays a low enough
        permeability to impede the migration of contaminants
        to any stratigraphically lower water-bearing units?
    3.  Is the confining layer laterally continuous across
        the entire site?
    4.  Did the owner/operator consider the chemical
        compatibility of the site-specific waste types
        and the geologic materials of the confining layer?        (Y/N)
    5.  Did the geologic assessment address or provide
        means for resolution of any information gaps of
        geologic data?                                            (Y/N)
    6.  Does the laboratory data corroborate the field
        data for petrography?                                     (Y/N)
    7.  Does the laboratory data corroborate the field
        data for mineralogy and subsurface geochemistry?          (Y/N)

C.  Presentation of geologic data

    1.  Did the owner/operator present at least four
        geologic cross sections of the site?                      (Y/N)
    2.  Do each of these cross sections:
        •  identify the types and characteristics of
           the geologic materials present?
        •  define the contact zones between different
           geologic materials?
        •  note the zones of high permeability or
           fracture?
        •  give detailed borehole information including:
           — location of borehole?                               (Y/N)
           — depth of termination?                               (Y/N)
           — location of screen (if applicable)?                 (Y/N)
           — depth of zone of saturation?                        (Y/N)
    3.  Did the owner/operator provide a topographic map which
        was constructed by a licensed surveyor?                   (Y/N)
    4.  Does the topographic map provide:
        •  contours at a maximum interval of two-feet?            (Y/N)
        •  locations and illustrations of man-made
           features (e.g., parking lots, factory
           buildings, drainage ditches, storm drains,
           pipelines, etc.)?                                      (Y/N)
           descriptions of nearby water bodies?                   (Y/N)
           descriptions of off-site wells?                        (Y/N)
           site boundaries?                                       (Y/N)
           individual RCRA units?                                 (Y/N)
           delineation of the waste management area(s)?           (Y/N)
           well and boring locations?                             (Y/N)
                               Al-5

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        5.  Did the owner/operator provide an aerial photo-
            graph depicting the site and adjacent off-site
            features?                                                 (Y/N).
        6.  Does the photograph clearly show surface water
            bodies, adjacent municipalities, and residences
            and are these clearly labelled?                           (Y/N)_
III.  Identification of Ground-Water Flowpaths

    A.  Ground-water flow direction

        1.  Was the well casing height measured by a
            licensed surveyor to the nearest 0.1 feet?
        2.  Were the well water level measurements taken
            within a 24 hour period?
        3.  Were the well water level measurements taken
            to the nearest 0.1 feet?
        4.  Were the well water levels allowed to stabilize
            after construction and development for a
            minimum of 24 hours prior to measurements?                (Y/N)_
        5.  Was the water level information obtained
            from (check appropriate one):
            •  multiple piezometers placement in single
               boreholes?                                             	
            •  vertically nested piezometers in closely spaced
               separate boreholes?                                    	
        6.  Did the owner/operator provide construction
            details for the piezomete's?                              (Y/N).
        7.   How were the static water levels measured (check
             method(s).
                  Electric water sounder                    	
               -  Wetted tape                               	
               -  Air line                                  	
               -  Other (explain)                           	
            Was the well water level measured in wells
            drilled to an equivalent depth below the
            saturated zone,  or screened at an equivalent
            depth below the  saturated zone?                           (Y/N).
            Has the owner/operator provided a site water table
            (potentiometric) contour map?  If yes,                    (Y/N)_
            •  Do the potentiometric contours appear logical
               based on topography and presented data?
               (Consult water level data)                             (Y/N).
            •  Are ground-water flowlines indicated?                  (Y/N).
            •  Are static water levels shown?                         (Y/N).
            •  Can hydraulic gradients be estimated?                  (Y/N).
                                   Al-6

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    10. Did the owner/operator develop two, or more,
        hydrologic cross sections of the vertical flow
        component across the site?                                (Y/N)
    11. Do the owner/operator's flow nets include:
        •  piezometer locations?                                  (Y/N).
        •  depth of screening?                                    (Y/N)_
        •  width of screening?                                    (Y/N)_

B.  Seasonal and temporal fluctuations in ground-water level

    1.  Do fluctuations in static water levels occur?             (Y/N)
        •  If yes, are the fluctuations caused by any of
           the following:
           — Off-site well pumping                               (Y/N).
           — Tidal processes or other intermittent natural
              variations (e.g., river stage, etc.)                (Y/N).
           — On-site well pumping                                (Y/N)
           — Off-site, on-site construction or changing
              land use patterns                                   (Y/N).
           — Deep well injection                                 (Y/N).
           — Seasonal variations                                 (Y/N)
           — Other (specify) 	
    2.  Has the owner/operator documented the source and
        patterns that contribute to or affect the ground-water
        patterns below the waste management                       (Y/N)
    3.  Do the water level fluctuations alter the general
        ground-water gradients and flow directions?               (Y/N).
    4.  Based on water level data, do any head differ-
        entials occur that may indicate a vertical flow
        component in the saturated zone?                          (Y/N).
    5.  Did the owner/operator implement means for gauging
        long term effects on water movement that may result
        from on-site or off-site construction or changes
        in land-use patterns?                                     (Y/N).

C.  Hydraulic conductivity

    1.  How were hydraulic conductivities of the subsurface
        materials determined?
        •  Single-well tests (slug tests)?                        (Y/N).
        •  Multiple-well tests (pump tests)?                      (Y/N).
    2.  If single-well tests were conducted, was it done
        by:
           -  Adding or removing a known volume of water,         (Y/N)
              Or
           -  Pressurizing well casing                            (Y/N)_
                               Al-7

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    3.  IE single well tests were conducted in a highly
        permeable formation, were pressure transducers
        and high-speed recording equipment used to
        record the rapidly changing water levels?                 (Y/N)_
    4.  Since single well tests only measure hydraulic
        conductivity in a limited area, were enough
        tests run to ensure a representative measure
        of conductivity in each hydrogeologic unit?               (Y/N)_
    5.  Is the owner/operator's slug test data
        (if applicable) consistent with existing
        geologic information (e.g., boring logs)?                 (Y/N).
    6.  Were other hydraulic conductivity properties
        determined?                                               (Y/N).
    7.  If yes, provide any of the following data, if
        available:
        •  Transmissivity                            	
        •  Storage coefficient
        •  Leakage
        •  Permeability                              	
        •  Porosity                                  	
        •  Specific capacity                         	
        •  Other (specify) 	

D.  Identification of the uppermost aquifer

    1.  Has the extent of the uppermost saturated zone
        (aquifer) in the facility area been defined?  If yes,     (Y/N).
        •  Are soil boring/test pit logs included?                (Y/N).
        •  Are geologic cross-sections included?                  (Y/N).
    2.  Is there evidence of confining (competent,
        unfractured, continuous, and low permeability)
        layers beneath the site?                                  (Y/N).
        •  If yes, was continuity demonstrated through the
           evidence of lack of drawdown in the upper well
           when separate, closely-spaced wells (one screened
           at the uppermost part of the water table, and
           the other screened on the lower side of the
           confining layer) are pumped simultaneously?            (Y/N).
    3.  Was hydraulic conductivity of the confining unit
        determined to be less than 10~7 cm/sec through
        direct field measurements?                                (Y/N).
    4.  Does potential for other hydraulic interconnect-
        tion exist (e.g., lateral incontlnuity between
        geologic units, facies changes, fracture zones,
        cross cutting structures, or chemical corrosion/
        alteration of geologic units by leachate)?                (Y/N).
                               Al-8

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IV.   Conclusions

    A.   Subsurface geology

        1.  Has sufficient data been collected to adequately
            define petrography and petrographic variation?            (Y/N)
        2.  Has the subsurface geochemistry been adequately
            defined?                                                  (Y/N).
        3.  Was the boring/coring program adequate to define
            subsurface geologic variation?                            (Y/N)
        4.  Was the owner/operator's narrative description
            complete and accurate in its interpretation
            of the data?                                              (Y/N).
        5.  Does the geologic assessment address or provide
            means to resolve any information gaps?                    (Y/N)_

    B.   Ground-water flowpaths

        1.  Did the owner/operator adequately establish the
            horizontal and vertical components of ground-
            water flow?                                               (Y/N).
        2.  Were appropriate methods used to establish
            ground-water flowpaths?                                   (Y/N)
        3.  Did the owner/operator provide accurate
            documentation?                                            (Y/N)
        4.  Are the potentiometric surface measurements
            valid?                                                    (Y/N).
        5.  Did the owner/operator adequately consider the
            seasonal and temporal effects on the ground-
            water?                                                    (Y/N).
        6.  Were sufficient hydraulic conductivity tests
            performed to document lateral and vertical
            variation in hydraulic conductivity in the
            entire hydrogeologic subsurface below the
            site?                                                     (Y/N)_

    C.   Uppermost aquifer

        1.  Did the owner/operator adequately define the
            uppermost aquifer?                                        (Y/N)_
                                   Al-9

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                                  APPENDIX A.2

                PLACEMENT OF DETECTION MONITORING WELLS WORKSHEET
     The following worksheets are designed to assist the enforcement officer's
evaluation of an owner/operator's approach for selecting the number, location,
and depth of all detection phase monitoring wells.  This series of worksheets
has been compiled to closely track the information presented in Chapter 2 of
the TEGD.  The guide for the evaluation of an owner/operator's placement of
monitoring wells is highly dependent upon a thorough characterization of the
site hydrogeology as described in Chapter 1 of the TEGD and Appendix A.I
worksheets.
I.   Placement of Downgradient Detection Monitoring Wells

    A.  Are the ground-water monitoring wells or clusters located
        immediately adjacent to the waste management area?            (Y/N)_
    B.  How far apart (i.e., what is the spacing?) between detection
        monitoring well locations?
        Does the owner/operator provide a rationale for the
        location of each monitoring well or cluster?                  (Y/N)
        Does the owner/operator provide an explanation for the
        spacing of the ground-water monitoring wells?                 (Y/N)
        Has the owner/operator identified the vertical sampling
        interval(s) of each monitoring well or cluster, i.e.,
        depth and thickness?                                          (Y/N).
        Does the owner/operator provide an explanation for the
        depth and thickness of the vertical sampling interval(s)
        for each monitoring well or cluster?                          (Y/N)
        What length screens has the owner/operator employed in
        the ground-water monitoring wells on site?
    H.   Does the owner/operator provide an explanation for the
        screen length(s) chosen?                                      (Y/N)_
    I.   Do the actual locations of monitoring wells or clusters
        correspond to those identified by teh owner/operator?         (Y/N)_
                                   A2-1

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II.  Placement of Upgradient Monitoring Wells

    A.  Has the owner/operator documented the location of each
        upgradient monitoring well or cluster?                        (Y/N)
    B.  Does the owner/operator provide an explanation for the
        location(s) of the upgradient monitoring wells?               (Y/N)
    C.  Has the owner/operator provided a rationale for the
        depth and thickness of the vertical sampling interval
        for each background monitoring well or cluster?               (Y/N)_
    D.  What length screens has the owner/operator employed in
        the background monitoring well(s)?
    E.  Does the owner/operator provide an explanation for the
        screen length(s) chosen?                                      (Y/N)
    F.  Does the actual location of each background monitoring
        well or cluster correspond to that identified by the
        owner/operator?                                               (Y/N).
III.  Conclusions

    A.  Downgradient Wells

        Do the location,  spacing,  and vertical sampling interval(s)
        of the ground-water monitoring wells or clusters in the
        detection monitoring system allow the immediate detection
        of a release of hazardous  waste or constituents from the
        hazardous waste management area to the uppermost aquifer?     (Y/N)

    B.  Upgradient Wells

        Do the location and vertical sampling interval(s) of the
        upgradient (background) ground-water monitoring wells
        ensure the capability of collecting ground-water samples
        representatiave of upgradient (background) ground-water
        quality including any ambient heterogeneous chemical
        characteristics?                                              (Y/N)
                                   A2-2

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                                  APPENDIX A.3

                MONITORING WELL  DESIGN AND CONSTRUCTION WORKSHEET
     The following worksheets have been designed to assist the enforcement
officer in evaluating the techniques used by an owner/operator for designing
and constructing monitoring wells.  This series of worksheets has been
compiled to parallel the information presented in Chapter 3 of the TEGD.
I.  Monitoring Well Design

     A. Complete the attached well construction summary sheet for the
        monitoring well unless similar documentation is already available
        from the owner/operator.  Include the locations where the well
        intercepts changes in geological formation.
II.  Drilling Methods

    A.  What drilling method was used for the well?
        •  Hoilow-stem auger
        •  Solid-stem auger
        •  Mud rotary
        •  Air rotary
        •  Reverse rotary
        •  Cable tool
        •  Jetting
        •  Air drill with casing hammer
        •  Other (specify) 	
    B.   Were any cutting fluids (including water) or additives
        used during drilling?                                         (Y/N).
        If yes,  specify
        Type of  drilling fluid 	
        Source of water used 	
        Foam 	
        Polymers 	
        Other 	

    C.   Was the  cutting fluid, or additive,  analyzed?                 (Y/N)_

    D.   Was the  drilling equipment steam-cleaned prior to drilling
        the well?                                                     (Y/N)_

    E.   Was compressed air used during drilling?                      (Y/N)
        1.  If yes,  was the air treated to remove oil (e.g.,
            filtered)?                                                (Y/N)
                                      A3-1

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  MOJCCT
  sire   _
  DATE  COMPLETED

               BY _
                                       WELL NO.


                                       AOUIFIE* -
  ELEVATION
X
&
«
c
«t
                                      Elevation of  reference point
                                      Height of reference point
                                             Mirfac*
                                      tkpth of »wrf«c«

                                      Type of  »urf«et M«1
                                      1.0.  of  »wrf«e« C«tin9
                                      Type  of  turfact easing:
                                      Depth of  »urf«e« casing
                                      l.O. of  ris«r pipt
                                      Typ« of  riMr pipt:
I •    0i«««t«r of bortholt
                              -\m - Typt of  fill.r:
       CltV*tiOA /
       Type of M«l:
                                                       of tOP Of M«l
                                      Typ* of  grav* I pack
                                      Cl«v./4«ptn of top of
                                      Elevation  / tftpth of top of tcr»«n
                                      Description of screen  _______
                                      I.S. of  screen section

                                      Elevation  / depth of bottom of screen
                                          . /depth of bottom of gravel  pack
                                      E lev. /depth of bottom of plugged
                                      blank section

                                      Type  of  filler below plugged
                                      section
                                      Elevation of DOT cor* of
                                             Well  Construction  Suasary.
                                               A3-2

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    F.  Did the owner/operator document procedure for establishing
        the water table?                                              (Y/N),
        1.  If yes, how was the location established?
    G.  Formation samples
        1.  Were continuous formation sample cores collected during
            drilling?                                                 (Y/N).
        2.  How were the samples obtained?
            •  Split spoon                                     	
            •  Shelby tube                                     	
            •  Core drill                                      	
            •  Other (specify) 	
        3.  Indicate the frequency at which formation samples were
            collected                         	
        4.  Identify if any physical and/or chemical tests were per-
            formed on the formation samples (specify) 	
III.   Monitoring Well Construction Materials

    List of Potential Construction Materials for the Saturated Zone

    1.  Stainless steel (316)
    2.  Teflon

    A.  Identify construction  materials (by number)  and diameters
        (ID/OD)
                                                         Diameter
                                          Material        (ID/OD)

        1.   Primary Casing                	        	
        2.   Secondary or  outside casing   	        	
            (double construction)
        3.   Screen
    B.   How are  the  sections  of  casing and  screen connected?
            •  Pipe  sections  threaded
            •  Couplings  (friction) with  adhesive or  solvent
            •  Couplings  (friction) with  retainer screws
            •  Other (specify) 	
    C.  Were  the materials  steam-cleaned  prior  to  installation?        (Y/N)_
                                     A3-3

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IV.  Well Intake Design and Well Development

    A.  Was a well intake screen installed?                            (Y/N)_
        1.  What is the length of the screen for the well?
        2.  Is the screen manufactured?                                (Y/N).
    B.  Was a filter pack installed?                                   (Y/N).
        1.  Has a turbidity measurement of the well water ever
            been made?                                                 (Y/N)_
    C.  Well development
        1.  What technique was used for well development?
            •  Surge block                                   	
            •  Bailer                                        	
            •  Air surging                                   	
            •  Water pumping                                 	
            •  Other (specify) 	
V.  Annular Space Seals

    A.  Is the annular space in the saturated zone directly above
        the filter pack filled with?
            •  Sodium bentonite (specify type and grit)

            •  Cement (specify neat or concrete) 	
            •  Other (specify) 	
        1.  Was the seal installed by?
            •  Dropping material down the hole and tamping
            •  Dropping material down the inside of
               hollow-stem auger
            •  Tremie pipe method
            •  Other (specify) 	
    B.  Was a different seal used in the unsaturated zone?             (Y/N)
        If yes,
        1.  Was this seal made with?
            •  Sodium bentonite (specify type and grit) 	

            •  Cement (specify neat or concrete) 	
            •  Other (specify) 	
        2.  Was this seal installed by?
            •  Dropping material down the hole and tamping
            •  Dropping material down the inside of
               hollow-stem auger
            •  Tremie pipe method
            •  Other (specify) 	
    C.  Is the upper portion of the borehole sealed with a concrete
        cap to prevent infiltration from the surface?                 (Y/N)
                                      A3-4

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    D.  Is the well fitted with an above-ground protective device?     (Y/N)
    E.  Has the protective cover been installed with locks to
        prevent tampering?                                             (Y/N)
VI.  Field Tests/Field Demonstration

    A.  Do field measurements of the following agree with
        reported data:
        1.  Casing diameter?                                           (Y/N).
        2.  Well depth?                                                (Y/N).
        3.  Water level elevation?                                     (Y/N).

    B.  If the existing well is being field demonstrated, complete
        Questions 1 through 7.
        1.  Is the location of the demonstration well hydraulically
            equivalent to the existing well?                           (Y/N).
        2.  Was the demonstration well installed using EPA-approved
            methods and materials?                                     (Y/N)_
        3.  How were the wells evacuated (e.g., bailer or bladder
            pump)?
            existing well: 	
            demonstration well: 	
        4.  Were the wells sampled concurrently?                       (Y/N)
        5.  Were the wells each sampled using the appropriate EPA
            methodology?                                               (Y/N).
        6.  What parameters were the ground water samples analyzed
            for?
        7.  Are the values for these parameters equivalent for each
            well (i.e., within the acceptable standard deviations)?   (Y/N).
VII.  Conclusions

    A.  Do the design and construction of the owner/operator's
        ground-water monitoring wells permit depth discrete ground-
        water samples to be taken?                                    (Y/N)

    B.  Are the samples representative of ground-water quality?       (Y/N).

    C.  Are the ground-water monitoring wells structurally stable?    (Y/N).

    D.  Does the ground-water monitoring well's design and con-
        struction permit an accurate assessment of aquifer
        characteristics?                                              (Y/N)
                                      A3-5

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                                  APPENDIX A.4

                         SAMPLING AND ANALYSIS WORKSHEET
     The following worksheets have been designed to assist the enforcement
officer in evaluating the techniques an owner/operator uses to collect and
analyze ground-water samples.  This series of worksheets have been compiled
based on the information provided in Chapter 4 of the TEGD.
I.  Review of Sample Collection Procedures

     A.  Measurement of well depths elevation:

        1.  Are measurements of both depth to standing water
            and depth to the bottom of the well made?                 (Y/N)_
        2.  Are measurements taken to the nearest centimeter
            or 0.1 feet?                                              (Y/N).
        3.  What device is used?
        4.  Is there a reference point established by a licensed
            surveyor?                                                 (Y/N).

    B.   Detection of immiscible layers:
        1.  Are procedures used which will detect light phase
            immiscible layers?                                        (Y/N).
        2.  Are procedures used which will detect heavy phase
            immiscible layers?                                        (Y/N).

    C.   Sampling of immiscible layers:
        1.  Are the immiscible layers sampled separately prior to
            well evacuation?                                          (Y/N).
        2.  Do the procedures used minimize mixing
            with water soluble phases?                                (Y/N)_

    D.   Well evacuation:
        1.  Are low yielding wells evacuated to dryness?              (Y/N)
        2.  Are high yielding wells evacuated so that at least
            three casing  volumes are removed?                         (Y/N).
        3.  What device is used to evacuate the wells?

        4.  If any problems are encountered (e.g.,  equipment
            malfunction)  are they noted in a field logbook?           (Y/N)_
    E.   Sample withdrawal:
        1.  For low yielding wells,  are samples for volatiles, pH,
            and oxidation/reduction potential drawn first  after
            the well recovers?                                        (Y/N)
                                      A4-1

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   10.
   11,
   12.
   13.

   14.
Are samples withdrawn with either Teflon or stainless
steel (316) sampling devices?                              (Y/N)_
Are sampling devices either bottom valve bailers
or positive gas displacement bladder pumps?                (Y/N)
If bailers are used, is "Teflon"-coated wire, single
strand stainless steel wire, or monofilament used to
raise and lower the bailer?                                (Y/N).
If bladder pumps are used, are they operated in a
continuous manner to prevent aeration of the sample?       (Y/N)_
If bailers are used, are they lowered slowly to
prevent degassing of the water?                            (Y/N)
If bailers are used, are the contents transferred
to the sample container in a way that will minimize
agitation and aeration?                                    (Y/N)
Is care taken to avoid placing clean sampling equipment
on the ground or other contaminated surfaces prior to
insertion into the well?                                   (Y/N).
If dedicated sampling equipment is not used, is
equipment disassembled and thoroughly cleaned between
samples?                                                   (Y/N).
If samples are for inorganic analysis, does the clean-
ing procedure include the following sequential steps:
a.  Dilute acid rinse (HNO3 or HC1)?                       (Y/N).
b.  Distilled/deionized water rinse?                       (Y/N).
If samples are for organic analysis, does the cleaning
procedure include the following sequential steps:
a.  Nonphosphate detergent wash?                           (Y/N).
b.  Tap water rinse?                                       (Y/N).
c.  Distilled/deionized water rinse?                       (Y/N).
d.  Acetone rinse?                                         (Y/N)
e.  Pesticide-grade hexane rinse?                          (Y/N)_
Is sampling equipment thoroughly dry before use?           (Y/N).
Are equipment blanks taken to ensure that sample
cross-contamination has not occurred?                      (Y/N).
If volatile samples are taken with a positive gas
displacement bladder pump, are pumping rates below
100 ml/min?                                                (Y/N)
F.  In-situ or field analyses:
    1.  Are the following labile (chemically unstable) parameters
        determined in the field:
        a.  pH?                                                   (Y/N).
        b.  Temperature?                                          (Y/N).
        c.  Specific conductivity?                                (Y/N).
        d.  Redox potential?                                      (Y/N).
        e.  Chlorine?                                             (Y/N).
        f.  Dissolved oxygen?                                     (Y/N).
        g.  Turbidity?                                            (Y/N).
        h.  Other (specify) 	
                                  A4-2

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            For in-situ determinations, are they made after well
            evacuation and sample removal?                            (Y/N)
            If sample is withdrawn from the well, is parameter
            measured from a split portion?                            (Y/N)
            Is monitoring equipment calibrated according to
            manufacturers' specifications and consistent with
            SW-846?                                                   (Y/N).
            Is the date, procedure, and maintenance for equipment
            calibration documented in the field logbook?              (Y/N).
II.   Review of Sample Preservation and Handling Procedures

    A.   Sample containers:
        1.   Are samples transferred from the sampling device
            directly to their compatible containers?                  (Y/N).
        2.   Are sample containers for metals (inorganics) analyses
            polyethylene with polypropylene caps?                     (Y/N)
        3.   Are sample containers for organics analysis glass
            bottles with Teflon-lined caps?                           (Y/N).
        4.   If glass bottles are used for metals samples are
            the caps Teflon-lined?                                    (Y/N).
        5.   Are the sample containers for metal analyses cleaned
            using these sequential steps?
            a.  Nonphosphate detergent wash?                          (Y/N)
            b.  1:1 nitric acid rinse?                                (Y/N).
            c.  Tap water rinse?                                      (Y/N).
            d.  1:1 hydrochloric acid rinse?                          (Y/N).
            e.  Tap water rinse?                                      (Y/N).
            f.  Distilled/deionized water rinse?                      (Y/N)_
        6.   Are the sample containers for organic analyses cleaned
            using these sequential steps?
            a.  Nonphosphate detergent/hot water wash?                (Y/N)_
            b.  Tap water rinse?                                      (Y/N)_
            c.  Distilled/deionized water rinse?                      (Y/N)_
            d.  Acetone rinse?                                        (Y/N)_
            e.  Pesticide-grade hexane rinse?                         (Y/N)_
        7.   Are trip blanks used for each sample container type
            to verify cleanliness?                                    (Y/N)_

    B.   Sample preservation procedures:
        1.   Are samples for the following analyses cooled to 4°C:
            a.  TOC?                                                  (Y/N)_
            b.  TOX?                                                  (Y/N)~
            c.  Chloride?                                             (Y/N)_
            d.  Phenols?                                               (Y/N)_
            e.  Sulfate?                                               (Y/N)~
            f.   Nitrate?                                               (Y/N)
                                     A4-3

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        g.  Coliform bacteria?
        h.  Cyanide?
        i.  Oil and grease?
        j.  Hazardous constituents (§261, Appendix VIII)?
    2.  Are samples for the following analyses field acidified
        pH <2 with HNO3:
        a.  Iron?
        b.  Manganese?
        c.  Sodium?
        d.  Total metals?
        e.  Dissolved metals?
        f.  Fluoride?
        g.  Endrin?
        h.  Lindane?
        i.  Methoxychlor?
        j.  Toxaphene?
        k.  2,4 D?
        1.  2,4,5, TP Silvex?
        m.  Radium?
        n.  Gross alpha?
        o.  Gross beta?
    3.  Are samples for the following analyses field acidified
        to pH <2 with H2SO4:
        a. Phenols?
        b. Oil and grease?
    4.  Is the sample for TOC analyses field acidified to
        pH <2 with HC1?
    5.  Is the sample for TOX analysis preserved with
        1 ml of 1.1 M sodium sulfite?
    6.  Is the sample for cyanide analysis preserved with
        NaOH to pH >12?
C.  Special handling considerations:
    1.  Are organic samples handled without filtering?
    2.  Are samples for volatile organics transferred to
        the appropriate vials to eliminate headspace over
        the sample?
    3.  Are samples for metal analysis split into two
        portions?
    4.  is the sample for dissolved metals filtered
        through a 0.45 micron filter?
    5.  Is the second portion not filtered and analyzed
        for total metals?
    6.  Is one equipment blank prepared each day of
        ground-water sampling?
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
to
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N)
   (Y/N).

   (Y/N).

   (Y/N).

   (Y/N).


   (Y/N).


   (Y/N).

   (Y/N).

   (Y/N).

   (Y/N).

   (Y/N)
                                  A4-4

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III.  Review of Analytical Procedures

    A.  Laboratory analysis procedures:
        1.  Are all samples analyzed using an EPA-approved
            method (SW-846)?                                           (Y/N).
        2.  Are appropriate QA/QC measures used in laboratory
            analysis (e.g., blanks, spikes, standards)?                (Y/N).
        3.  Are detection  limits and percent recovery  (if
            applicable) provided for each parameter?                   (Y/N)
        4.  If a new analytical method or laboratory is used,
            are split samples run for comparison purposes?             (Y/N)
        5.  Are samples analyzed within specified holding
            times?                                                     (Y/N).

    B.  Laboratory logbook:
        1.  Is a laboratory logbook maintained?                        (Y/N)
        2.  Are experimental conditions (e.g., temperature,
            humidity,  etc.) noted?                                     (Y/N)_
        3.  If a sample for volatile analysis is received
            with headspace, is this noted?                             (Y/N)_
        4.  Are the results for all QC samples identified?             (Y/N)]
        5.  Is the time, date, and name of person noted
            for each processing step?                                  (Y/N)_
IV.   Review of Chain-of-Custody Procedures

    A.   Sample labels:
        1.   Are sample  labels used?                                   (Y/N).
        2.   Do they provide the following information:
            a. Sample identification number?                          (Y/N).
            b. Name of  collector?                                     (Y/N).
            c. Date and time of collection?                           (Y/N).
            d. Place of collection?                                   (Y/N)]
            e. Parameter(s) requested and preservatives used:          (Y/N)
        3.   Do they remain legible even if wet?                       (Y/N)
    B.   Sample seals:
        1.   Are sample  seals placed on those containers to
            ensure the  samples are not altered?                       (Y/N)
    C.   Field  logbook:
        1.   Is a field  logbook maintained?                            (Y/N).
        2.   Does it  document  the following:
            a.  Purpose  of  sampling (e.g.,  detection or
               assessment)?                                            (Y/N)
            b.  Location of well(s)?                                   (Y/N)
            c.  Total  depth of each well?                               (Y/N)]
            d.  Static water  level  depth and  measurement
               technique?                                              (Y/N)
                                     A4-5

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        e. Presence of immiscible layers and
           detection method?
        f. Collection method for immiscible layers
           and sample identification numbers?
        g. Well evacuation procedures?
        h. Sample withdrawal procedure?
        i. Date and time of collection?
        j. Well sampling sequence?
        k. Types of sample containers and sample
           identification numbers?
        1. Preservative(s) used?
        m. Parameters requested?
        n. Field analysis data and method(s)?
        o. Sample distribution and transporter?
        p. Field observations?
           •  unusual well recharge rates?
           •  Equipment malfunction(s)?
           •  Possible sample contamination?
           •  Sampling rate?
        q. Field team members?

D.  Chain-of-custody record:
    1.  Is a chain-of-custody record included with
        each sample?
    2.  Does it document the following:
        a. Sample number?
        b. Signature of collector?
        c. Date and time of collection?
        d. Sample type?
        e. Station location?
        f. Number of containers?
        g. Parameters requested?
        h. Signatures of persons involved in the
           chain-of-possession?
        i. Inclusive dates of possession?
E.  Sample analysis request sheet:
    1.  Does a sample analysis request sheet accompany
        each sample?
    2.  Does the request sheet document the following:
        a. Name of person receiving the sample?
        b. Date of sample receipt?
        c. Laboratory sample number (if different than
           field number)?
        d. Analyses to be performed?

F.  Laboratory logbook:
    1.  Is a laboratory logbook maintained?
    2.  If so,  does it document the following:
        a. Sample preparation techniques (e.g., extraction)?
        b. Instrumental methods?
        c. Experimental conditions?
(Y/N).

(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N).

(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N).

(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N).

(Y/N)
(Y/N)
(Y/N).

(Y/N)
(Y/N).

(Y/N)
(Y/N).


(Y/N).

(Y/N)
(Y/N)
(Y/N)
                                  A4-6

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V.  Review of Quality Assurance/Quality Control

    A.  Is the validity and reliability of the laboratory and
        field generated data ensured by a QA/QC program?              (Y/N)

    B.  Does the QA/QC program include:
        1.  Documentation of any deviations from approved
            procedures?                                               (Y/N).
        2.  Documentation of analytical results for:
            a. Blanks?                                                (Y/N).
            b. Standards?                                             (Y/N).
            c. Duplicates?                                            (Y/N).
            d. Spiked samples?                                        (Y/N).

    C.  Are approved statistical methods used?                        (Y/N)

    D.  Are QC samples used to correct data?                          (Y/N)

    E.  Are all data critically examined to ensure it
        has been properly calculated and reported?                    (Y/N)
VI.  Review of Indicators of Data Quality

    A.  Reporting of low and zero concentration values:
        1.  Do specific concentration values accompanying
            measurements reported as less than a limit of
            detection?                                                (Y/N).
        2.  is the magnitude of detection limits consistent
            throughout the data set for each parameter?               (Y/N)
        3.  Have techniques described in Appendix B of
            40 CFR §136 been used to determine the detection
            limits?                                                   (Y/N).
        4.  Has the method for using less than detection
            limit data in presentations and statistical
            analysis been documented?                                 (Y/N)_

    B.  Significant digits:
        1.  Are constituent concentrations reported with
            a consistent number of significant digits?                (Y/N)_
        2.  Are all indicator parameters reported with
            at least three significant  digits?                        (Y/N)_

    C.  Missing data values:
        1.  Is the monitoring data set  complete?                      (Y/N)
        2.  Are t-test  comparisons between upgradient  and
            downgradient wells attempted despite missing
            data provided that:
            a. At least one upgradient  and one downgradient
               well were sampled?                                     (Y/N)
                                      A4-7

-------
            b. In the case of a missing quarterly
               sampling set, values are assigned by
               averaging corresponding values for
               the other three quarters?                               (Y/N)_
            c. In the case of missing replicate values
               from a sampling event, values are assigned
               by averaging the replicate(s) which are
               available for that sampling event?                      (Y/N).
    D.  Outliers:
        1.  Have extreme values (outliers) of constituent
            concentrations deleted or otherwise modified
            because of:
            a. Incorrect transcription?                                (Y/N).
            b. Methodological problems or an unnatural
               catastrophic event?                                     (Y/N).
            c. Are these above occurrences fully
               documented?                                             (Y/N).
        2.  Are true but extreme values unaltered and
            incorporated in the analysis?                              (Y/N)_
    E.  Units of measure:
        1.  Are all units of measure reported accurately?              (Y/N)
        2.  Are the units of measure for a given chemical
            parameter used consistently throughout the
            report?                                                    (Y/N),
        3.  Do the reporting formats clearly indicate
            consistent units of measure throughout so that
            no ambiguity exists (i.e., do the units
            accompany each parameter instead of a
            statement, "all values are ppm unless
            otherwise stated")?                                        (Y/N)
VII.  Conclusions

    A.  Does the sampling and analysis plan permit the owner/
        operator to detect and, where applicable, assess the
        nature and extent of a release of hazardous constituents
        to ground water from the monitored hazardous waste
         management facility?                                          (Y/N).
                                      A4-8

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                                  APPENDIX A. 5

                 PRESENTING DETECTION MONITORING DATA WORKSHEET
     The following worksheets have been designed to assist the enforcement
official in evaluating the method an owner/operator uses in presenting and
statistically analyzing detection monitoring data.  This series of worksheets
has been compiled to parallel the information provided in Chapter 5 of the
TEGD.
I.  Presenting Detection Monitoring Data

    A.  Is the owner/operator using the reporting sheets
        as described in the TEGD (Chapter 5)?                         (Y/N).
    B.  Have all the detection monitoring data collected by the
        facility been obtained and reviewed?                          (Y/N).
II.  T-test and Number of Wells

    A.   Which t-test is in use:
        1.  Cochran's approximation to the Behrens-Fisher
            (CABF t-test)?
        2.  Averaged replicate t-test (AR t-test)?
        3.  Other,  describe:   	 	
    B.   Does the facility have more than one upgradient monitoring
        well?                                                         (Y/N)
III.   First Year's Data

    A.   Have upgradient wells been monitored to establish background
        concentrations of the following data on a quarterly basis for
        one year:
        1.   Appendix III parameters (§265.92(b)(1))?                  (Y/N)_
        2.   Ground-water quality parameters (§265.92(b)(2))?          (Y/N).
        3.   Ground-water contamination indicator parameters
            (S265.92(b)(3)>?                                          (Y/N).

    B.   Were four  replicate measurements obtained from each
        upgradient well during the first year of quarterly  detec-
        tion monitoring for indicator  parameters [§265.92(b)(3)]?     (Y/N)

    C.   Have the background mean and variance been determined for
        the §265.92(b)(3)  parameters using all the data obtained
        from the upgradient wells during the first year of  sampling?  (Y/N)_
                                   A5-1

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IV.  Subsequent Year's Data

    A.  Is monitoring data collected after the first year being
        compared with background data to determine possible
        groundwater contamination?                                     (Y/N)
    B.  Is the identified approved t-test being used properly to
        determine possible ground-water contamination?                 (Y/N)
    C.  Are the ground-water quality parameters in §265.92(b)(2)
        being measured at least annually?                              (Y/N)

    D.  Are the indicator parameters in §265,92(b)(3) being
        measured in at least four replicate samples from each
        well in the detection monitoring network at least
        semi-annually?                                                 (Y/N).
    E.  Are the indicator parameters collected on a semi-annual
        basis being used to estimate the mean and variance?            (Y/N)_
    F.  Is the elevation of the water table at each monitoring
        well determined each time a sample is collected?               (Y/N).
V.  Conclusions

    A.  Is the owner/operator adequately reporting and statis-
        tically analyzing the facility's monitoring well data?        (Y/N).

    B.  If the t-test indicated a significant incease in IP's for
        downgradient wells, were they resampled and reanalyzed?       (Y/N).

    C.  If the resampling still indicated a significant increase,
        was assessment monitoring begun?                              (Y/N).
                                   A5-2

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                                  APPENDIX A.6

                              ASSESSMENT MONITORING
     The following worksheets have been designed to assist the enforcement
officer in evaluating an owner/operator's assessment phase ground-water
monitoring program.  This series of worksheets has been compiled to parallel
the information presented in Chapter 6 of the TEGD.
I.   Review of Hydrogeologic Descriptions

    A.  Has the site's hydrogeologic setting been well characterized
        (refer to Appendix A.I of TEGD)?                              (Y/N).
        1.  Has the regional and local hydrogeologic setting
            been thoroughly described?                                (Y/N).
        2.  Is there sufficient direct field information?             (Y/N).
        3.  Is the information accurate and reliable?                 (Y/N).
        4.  Was the evaluation performed by a hydrogeologist?         (Y/N)_
        5.  Did indirect investigatory methods correlate with
            direct methods?                                           (Y/N).
        6.  Have all possible migration pathways been identified?     (Y/N).
        7.  Will the description of the hydrogeologic setting aid
            in characterizing the rate and extent of the plume
            migration?                                                (Y/N).
II.  Review of Detection Monitoring System Description

    A.  Is the detection monitoring system capable of detecting
        all contaminant leakage that may be escaping from the
        facility (refer to Appendix A.2 of TEGD)?                     (Y/N).
        1.  Are the well designs and construction parameters
            fully documented?                                         (Y/N).
        2.  Have the downgradient wells been strategically
            located so as to intercept migrating contaminants?        (Y/N)
        3.  Are upgradient wells positioned so that they are
            not effected by the facility?                             (Y/N),
        4.  Are the screened intervals 10 feet or less?               (Y/N)"
        5.  Are the well construction materials (e.g., casing,
            screen, seals, pacxing) comprised of material that
            will not affect the ground-water quality?                 (Y/N).
III.  Review of Description of Approach for Making First Determination

    A.  Did the detection monitoring system consistently yield
        statistically equivalent concentrations for all indicator
        parameters?                                                   (Y/N).

                                   A6-1

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        If no:
        1.  Were the results based on the Student's t-test at the
            0.01 level of significance?  (Single-tailed t-test for
            testing significant increases and two-tailed t-test
            for testing significant differences in pH values.)        (Y/N)
        2.  Were the calculations performed correctly?                (Y/N)
        3.  If the results are deemed as a false positive, did
            the owner/operator fully document the reasoning?          (Y/N).
        4.  Is there any reasonable cause to believe that faulty
            data are responsible for the false positive claim?        (Y/N)
        5.  Can or will deficiencies in well design, sample
            collection, sample preservation, or analysis be
            corrected?                                                (Y/N).
        6.  If the owner/operator intends to collect additional
            data to remedy any inadequacies, will this collection
            result in an acceptable delay in assessing the extent
            of contamination at the site?                             (Y/N).
        7.  will positive results of these determinations initiate
            a drilling program for assessment monitoring?             (Y/N)
IV.  Review of Approach for Conducting Assessment

    A.   Have the assessment monitoring objectives been clearly
        defined in the assessment plan?
        1.  Does the plan include analysis and/or re-evaluation
            to determine if significant contamination has occurred
            in any of the detection monitoring wells?
        2.  Does the plan provide for a comprehensive program of
            investigation to fully characterize the rate and
            extent of contaminant migration from the facility?
        3.  Does the plan call for determining the concentrations
            of hazardous wastes and hazardous waste constituents
            in the ground water?
        4.  Does the plan employ a quarterly monitoring program?

    B.   Does the assessment plan identify the investigatory
        methods that will be used in the assessment phase?
        1.  Is the role of each method in the evaluation fully
            described?
        2.  Does the plan provide sufficient descriptions of the
            direct methods to be used?
        3.  Does the plan provide sufficient descriptions of the
            indirect methods to be used?
        4.  Will the method contribute to the further characteri-
            zation of the contaminant movement?
(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N)
                                   A6-2

-------
    C.  Are the investigatory techniques utilized in the assess-
        ment program based on direct methods?                          (Y/N)
        1.  Does the assessment approach incorporate indirect
            methods to further support direct methods?                 (Y/N)
        2.  Will the planned methods called for in the assessment
            approach ultimately meet performance standards for
            assessment monitoring?                                     (Y/N)
        3.  Are the procedures well defined?                           (Y/N).
        4.  Does the approach provide for monitoring wells similar
            in design and construction as the detection monitoring
            wells?                                                     (Y/N).
        5.  Does the approach employ taking samples during drill-
            ing or collecting core samples for further analysis?       (Y/N)

    D.  Are the indirect methods to be used based on reliable
        and accepted geophysical techniques?                           (Y/N).
        1.  Are they capable of detecting subsurface changes
            resulting from contaminant migration at the site?          (Y/N).
        2.  Is the measurement at an appropriate level of
            sensitivity to detect ground-water quality changes
            at the site?                                               (Y/N).
        3.  Is the method appropriate considering the nature
            of the subsurface materials?                               (Y/N)
        4.  Does the approach consider the limitations of
            these methods?                                             (Y/N).
        5.  Will the extent of contamination and constituent
            concentration be based on direct methods and sound
            engineering judgment?  (Using indirect methods to
            further substantiate the findings)                         (Y/N).

    E.  Does the assessment approach incorporate any mathematical
        modeling to predict contaminant movement?                      (Y/N)
        1.  Will site specific measurements be utilized to
            accurately portray the subsurface?                         (Y/N)_
        2.  Will the derived data be reliable?                         (Y/N)"
        3.  Have the assumptions been identified?                      (Y/N).
        4.  Have the physical and chemical properties of the
            site-specific wastes and hazardous waste constituents
            been identified?                                           (Y/N)
V.  Review of Assessment Monitoring Wells

    A.  Does the assessment plan specify:
        1.  The number, location, and depth of wells?                 (Y/N)
        2.  The rationale for their placement and identify the
            basis that will be used to select subsequent sampling
            locations and depths in later assessment phases?          (Y/N)
                                   A6-3

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B.  Does the assessment period consist of a phased investiga-
    tion so that data gained in initial rounds may help guide
    subsequent rounds?
    1.  Do initial rounds incorporate geophysical techniques
        to approximate the limits of the contaminant plume?
    2.  Has information from the triggering well (well show-
        ing elevated contaminant concentrations) been incor-
        porated in the initial design and specifications?
    3.  Is the sampling program designed adequately to portray
        a three dimensional plume configuration?

    4.  Are evaluation procedures in place that will provide
        further guidance for subsequent monitoring?

C.  Does sufficient hydrogeologic data exist in the direction
    of the contaminant plume?
    1.  Does the subsurface setting provide any information
        on possible transport mechanisms and attenuation
        processes?
    2.  Are provisions made to secure additional data as
        needed?
    3.  Are hydrogeologic descriptions updated as additional
        data become available?

D.  Sampling density:
    1.  Are a minimum of seven well clusters installed?
    2.  Are the well clusters placed both perpendicular and
        parallel to plume migration from the triggering well?
    3.  Are the well clusters placed both inside and outside
        the contaminant plume to identify its horizontal
        boundaries?
    4.  Are sampling locations situated so as to identify
        areas of maximum contaminant concentration within
        the plume?
    5.  Does the sampling density correlate with the size
        of the plume and the geologic variability?

E.  Sampling depths:
    1.  Are the intervals over which the samples are collected
        clearly identified?
    2.  Are the well screens within each cluster positioned
        to sample the full extent of the predicted vertical
        distribution of hazardous waste constituents?
    3.  Are the well screens depth discrete to the extent
        possible to minimize dilution effects?
    4.  Are there a minimum of five wells per cluster?
        •  Are at least three wells screened within the plume?
        •  Are at least two wells screened above and below
           the plume, respectively?
(Y/N).

(Y/N).



(Y/N).

(Y/N).



(Y/N).


(Y/N).



(Y/N).

(Y/N).

(Y/N).


(Y/N).

(Y/N).



(Y/N).


(Y/N).

(Y/N).



(Y/N).



(Y/N).

(Y/N)
(Y/N)
(Y/N).

(Y/N)
                               A6-4

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            Are the wells placed alternating lower and higher
            screened wells to reduce the effect of drawdown on
            the sampling horizons?                                    (Y/N)
            Are there high fluctuations in ground-water levels,
            or is the subsurface characterized by fractured
            consolidated formations that may otherwise require
            screen lengths greater than 10 feet?                      (Y/N).
            Are the wells screened to identify vertical concen-
            tration gradients and maximum concentrations of the
            contaminants?                                             (Y/N)
VI.  Review of Monitoring Well Design and Construction

    A.  Are the well design and construction specification require-
        ments equivalent to the detection requirements detailed in
        Chapter 3?                                                    (Y/N).
    B.  Are well design and construction details provided for:
        1.  Drilling methods?                                         (Y/N).
        2.  Well construction materials?                              (Y/N).
        3.  Well diameter?                                            (Y/N).
        4.  Well intake structures and procedures for well
            development?                                              (Y/N).
        5.  Placement of annular seals?                               (Y/N).

    C.  Are all these details approved and recommended considering
        the characteristics of the site?                              (Y/N)
VII.  Review of Sampling and Analysis Procedures

    A.  Does the list of monitoring parameters include all
        hazardous waste constituents from the facility?               (Y/N).
        1.  Does the water quality parameter list include other
            important indicators not classified as hazardous
            waste constituents?                                       (Y/N).
        2.  Does the owner/operator provide documentation for
            the listed wastes which are not included?                 (Y/N).
    B.  Have the procedures been detailed for sample collection?      (Y/N).
        1.  Do the procedures include evacuation of the borehole
            prior to sample collection?                               (Y/N).
        2.  Are special procedures delineated for collection of
            separate phase immiscible contaminants?                   (Y/N).
        3.  Has the equipment been identified?                        (Y/N).
        4.  Do the procedures include decontamination of equipment?   (Y/N)
        5.  Have pumping rates, duration, and position in the well
            from which water will be evacuated been specified?        (Y/N)_
                                   A6-5

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C.  Do the procedures include provisions for sample preser-
    vation and shipment?

D.  Do the procedures specify:
    1.  Type of sample containers?
    2.  Filtering procedures?
    3.  Preservation techniques?
    4.  Storage and time elements involved?
    5.  Proper documentation?
E.  Do these procedures correspond to recommended procedures
    (SW-846 or EPA-approved procedures) for sampling and
   1 preservation?

F.  Do the sampling and analysis procedures identify analyti-
    cal procedures for each of the identified monitoring
    parameters?

G.  Do the analytical procedures include:
    1.  Detailed description and reference of approved
        analytical methods?
    2.  QA/QC procedures?
    3.  Location of laboratory performing analysis?
    4.  Proper documentation?
    Does the sampling and analysis plan establish procedures
    for chain of custody control?

    Do these procedures include:
    1.  Sample labels?
    2.  Sample seals?
    3.  Field logbook?
    4.  Chain of custody record?
    5.  Sample analysis request sheet?
    6.  Laboratory logbook?

J.  Do the procedures specify how assessment monitoring data
    will be evaluated to determine if contamination has
    actually occurred?
    1.  Will the evaluation delineate the full extent of
        contaminant migration?
    2.  Will significant changes in containment concentration
        or movement be identified?
    3.  Are the evaluation procedures suitable and objective?

K.  Does the assessment plan clearly describe the procedures
    that will be used for evaluating monitoring data during
    the assessment?

L.  Does the plan provide for evaluation of its methodologies
    to ensure each method is properly executed during the
    assessment period?
H.
I.
                                                                  (Y/N).


                                                                  (Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N).


(Y/N).


(Y/N)
(Y/N)
(Y/N)
(Y/N)
(Y/N).
(Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
                                                                  (Y/N)
                               A6-6

-------
    M.  Is a list of all detection monitoring and assessment monitor-
        ing (if applicable) data available  from  the owner/operator?    (Y/N)
        1.  Do these lists include:
            •  Field quality control samples  (e.g., sample container
               and equipment blanks)?                                  (Y/N).
            •  Laboratory quality control samples (e.g.,  replicates,
               spiked samples, etc.)?                                  (Y/N).
        2.  Are the lists prepared using a  format which presents:
               Codes that identify GWCCs?                              (Y/N).
               Well number?                                            (Y/N).
               Date?                                                   (Y/N).
               Units of measure?                                       (Y/N).
               Less than (LT) detection limit values?                  (Y/N).
               Concentrations of GWCCs?                                (Y/N).

    N.  Has the owner/operator prepared summary  statistics tables
        of the GWCC data?                                              (Y/N).
        1.  Do the summary statistics  tables  include:
               Number of LT detection  limit values?                    (Y/N).
               Total number of values?                                (Y/N).
               Mean?                                                   (Y/N).
               Median?                                                 (Y/N).
               Standard deviation?                                     (Y/N).
               Coefficient of variation?                               (Y/N).
               Minimum value?                                          (Y/N).
               Maximum value?                                          (Y/N).
             re there summary statistics tables  that present:
               GWCC?                                                   (Y/N).
               GWCC by well number?                                    (Y/N).
               GWCC by well number and date?                           (Y/N)_
               Quality control data?                                   (Y/N).
    O.  Has the owner/operator simplified the statistical data?        (Y/N).
        1.  Was the data simplified using a ranking procedure  for
            each GWCC-well combination?                                (Y/N).
        2.  Has the ranking procedure  been applied to each GWCC
            which was detected at least once at  every well in  the
            monitoring system?                                         (Y/N)

    P.  Did the owner/operator display the data  graphically?           (Y/N)
        1.  Were the data plotted graphically to evaluate
            temporal changes?                                          (Y/N)_
        2.  Were the data plotted on facility maps to evaluate
            spacial trends?                                            (Y/N).
VIII.  Review of Migration Rates

    A.  Did the owner/operator's assessment plan specify the pro-
        cedures to be used to determine the rate of constituent
        migration in the ground-water?
(Y/N)
                                   A6-7

-------
    B.  Do the procedures incorporate a periodic re-evaluation of
        sampling data to continually monitor the rate and extent
        of contaminant migration?                                     (Y/N)
        1.  Do the procedures clearly establish ground-water flow
            rates and direction downgradient from the detection
            wells?                                                    (Y/N).
        2.  Are the methods employed suitable for these determina-
            tions?                                                    (Y/N).
        3.  Are the limitations of these methods known and
            documented?                                               (Y/N).
        4.  Do the evaluations incorporate chemical and physical
            characteristics of the contaminants and the media?        (Y/N).
        5.  Are adsorptive and degradative processes considered
            in determining any retardation of contaminant movement?   (Y/N).
        6.  Have the assumptions been identified and documented?      (Y/N).

    C.  Does the assessment plan evaluate the presence of
        immiscible phase layers?                                      (Y/N).
        1.  Do the procedures specify detection and collection
            of light and dense phase immiscibles prior to well
            evacuation?                                               (Y/N).
        2.  Has the owner/operator used the slope of the water
            table and the velocity of ground-water flow to estimate
            light phase immiscible migration?                         (Y/N).
        3.  Has the owner/operator defined the configuration of
            the confining layer to predict dense phase immiscible
            migration?-                                                (Y/N).
IX.  Reviewing Schedule of Implementation

    A.   Has the owner/operator specified a schedule of implementa-
        tion in the assessment plan?                                  (Y/N).
    B.   Does the schedule for implementing assessment monitoring
        data include a timetable for a comprehensive site evalua-
        tion for contamination?                                       (Y/N).
    C.   Does the timetable include:
        1.  A number of milestones used to judge if sufficient
            progress is being made toward the completion of the
            assessment during implementation?                         (Y/N).
        2.  The determination if contamination has occurred?          (Y/N).
        3.  Completing an initial comprehensive assessment of
            contamination at the site?                                (Y/N).
        4.  Implementing a program for continued monitoring after
            fully characterizing contamination at the site?           (Y/N).
    D.   Does this represent an acceptable time frame?                 (Y/N),
                                   A6-8

-------
X.  Conclusions

    A.  Has the owner/operator adequately characterized site
        hydrogeology to determine contaminant migration?              (Y/N)

    B.  Is the detection monitoring system adequately designed
        and constructed to immediately detect any contaminant
        release?                                                      (Y/N).

    C.  Are the procedures used to make a first determination of
        contamination adequate?                                       (Y/N)

    D.  Is the assessment plan adequate to detect, characterize,
        and track contaminant migration?                              (Y/N)

    E.  Will the assessment monitoring wells, given site hydro-
        geologic conditions, define the extent and concentration
        of contamination in the horizontal and vertical planes?       (Y/N)
    F.  Are the assessment monitoring wells adequately designed
        and constructed?                                              (Y/N).
    G.  Are the sampling and analysis procedures adequate to
        provide true measures of contamination?                       (Y/N).

    H.  Do the procedures used for evaluation of assessment
        monitoring data result in determinations of the rate of
        migration, extent of migration, and hazardous constituent
        composition of the contaminant plume?                         (Y/N)

    I.  Are the data collected at sufficient duration and frequency
        to adequately determine the rate of migration?                (Y/N)

    J.  Is the schedule of implementation adequate?                   (Y/N)

    K.  Is the owner/operator's assessment monitoring plan adequate?  (Y/N).
        1.  If the owner/operator had to implement his assessment
            monitoring plan, was it implemented satisfactorily?       (Y/N)
                                   A6-9

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                         APPENDIX B

METHODOLOGY AND EXAMPLE APPLICATIONS THAT DESCRIBE THE USE OF
      COCHRAN'S APPROXIMATION TO THE BEHRENS-FISHER AND
               THE AVERAGED REPLICATE T-TESTS

-------
BACKGROUND
     This appendix presents t-test methodologies that may be used by
owner/operators to analyze interim status detection monitoring ground-
water data.  The 40 CFR §265 Subpart F regulations require that owner/
operators use a students t-test to determine whether individual wells in
the monitoring network contain any indicator parameter concentrations
which are statistically greater than background concentrations measured
during the first year of sampling.  Several different t-tests can be
constructed to analyze interim status detection monitoring data and
during interim status, an owner/operator may choose a t-test which is
found to be most applicable to the data being analyzed.  However, owner/
operators must understand that for interim status facilities enforcement
officers will only accept one t-test methodology, which must be documented
with explicit examples and technical references.
     Two suggested t-test methodologies are presented in this appendix.
Cochran's Approximation to the Behrens-Fisher (CABF) t-test and a t-test
termed the Averaged Replicate (AR) t-test.  These tests are described
with the following organization: an introduction, methodology used to
analyze the first year's data, and methodology used to analyze data
collected after the first year.  After presentation of the methods an
example is analyzed using the CABF and AR methods.
COCHRAN'S APPROXIMATION TO THE BEHRENS-FISHER T-TEST
Introduction
     The methodology  for the CABF is presented for several reasons.
First, the CABF test  is referenced explicitly in  the 40 CFR §264 permit
regulations.  Prior guidance has directed use of  the CABF t-test.  The
CABF t-test is also widely documented and presented in many statistical
textbooks as a t-test  for use when two groups of  unpaired data with
different variances are under comparison.  Although the CABF  t-test has
been criticized widely because it may not match well with the ground-
water data collected  by interim status facilities, it will be described
because it is presently being used by interim status facilities.
                                    B-l

-------
Methodology Used to Analyze the First Year's Data
     Data collected during the first year from the upgradient wells are
used to estimate the background mean and variance.  All of the data
collected from the upgradient wells must be used.  If sampling were more
frequent than quarterly or if multiple upgradient wells yielded data then
all of these data should be included in the background mean and variance.
     The background mean (Xb) for the CABF t-test is:
                           "b   °b   Pb
                      Xb "  I    I    I   Xijk/Nb
                           i=l  j=l  k=l
          = Background concentration measurement from the ith well,
            the jth sampling period, and the kth replicate measurement,
            Where 1=1 to nb, j=l to ob, and k=l to pb.
     Nb   = Number of background measurements.

                               2
     The background variance (s ) for the CABF t-test is:

                  2   nb   °b   Pb             2
                 s  =  I    I    I  (Xijk - Xb) /Nb-l
                  b   i=l  j=l  k=l
Methodology Used to Analyze Data Collected After the First Year
     The data for each parameter from each monitoring well, from each
sampling event (upgradient and downgradient wells) after the first year
must be compared individually with the background data collected during
the first year.  Four replicate measurements should be taken from each
well for each indicator parameter (IP) during every semi-annual sampling
event.  These monitoring data are used to calculate a mean and variance
for every IP at every monitoring well each time the well system is sampled.
                                    B-2

-------
     The mean (Xm)  for monitoring well m for the CABF test is:





                                   Pm



                                   k=l
     where:   X^ = the kth replicate measurement from the mth

                   monitoring well.   Where k=l to pm.



             Nm  = number of replicate measurements from

                   monitoring well m.
                    2
     The variance (s )  for monitoring well m for the CABF test is:
                    m



                         2   P">          _  2

                        s  =  £   
-------
The critical t-statistic (tr) is calculated as follows:
where:  V.  = s. /N.
         b    b  b
                             W.  t.  + W  t
                           _  b  b T  m  m


                         C      W.  + W
                                 b *  m
        W  = s /N
         m    mm


        tfc = The critical value from Table B-l with (N^-l) degrees

             of freedom.



        tra = The critical value from Table B-l with (Nm-l) degrees

             of freedom.



(NOTE:  If pH is being tested use the two-tailed critical values,

otherwise use the one-tailed critical values).
The t* is then compared with t  using the following decision rules:



•  If specific conductivity, TOC, and TOX are being evaluated and  if


   t* is less than t  then there is no statistical indication that
                    c

   the IP concentrations are larger in the well under comparison than


   in the background data.  If t* is larger than t  then there  is  a


   statistical indication that IP concentrations are larger in  the


   well under comparison.



•  If pH is being evaluated and if  |t*|  (which is the absolute


   value of t* or t* without a + or - sign) is less than t  then


   there is no statistical indication that pH has changed.  If


   |t*| is larger than t  then there is  an indication that pH


   has changed statistically.  If t* is  negative then pH increased  if


   t* is positive pH decreased.
                               B-4

-------
                     TABLE B-l

    ONE AND TWO TAILED CRITICAL t VALUES AT THE
             .01 LEVEL OF SIGNIFICANCE

Degrees of
 Freedom            One Tailed          Two Tailed

    1                31.821              62.657
    2                 6.965               9.925
    3                 4.541               5.841
    4                 3.747               4.604
    5                 3.365               4.032
    6                 3.143               3.707
    7                 2.998               3.499
    8                 2.896               3.355
    9                 2.821               3.250
   10                 2.764               3.169
   11                 2.718               3.106
   12                 2.618               3.055
   13                 2.650               3.012
   14                 2.642               2.977
   15                 2.602               2.947
   16                 2.583               2.921
   17                 2.567               2.898
   18                 2.552               2.878
   19                 2.539               2.861
   20                 2.528               2.845
   21                 2.518               2.831
   22                 2.508               2.819
   23                 2.500               2.807
   24                 2.492               2.797
   25                 2.485               2.787
   26                 2.479               2.779
   27                 2.473               2.771
   28                 2.467               2.763
   29                 2.462               2.756
   30                 2.457               2.750
   40                 2.423               2.704
   60                 2.390               2.660
  120                 2.358               2.617
                      2.326               2.576
Adapted from Table III, Statistical Tables for
Biological, Agricultural, and Medical Research,
Fisher and Yates, 1949.
                       B-5

-------
AVERAGED REPLICATE T-TEST
Introduction
     The averaged replicate  (AR)  t-test methodology is presented for
several reasons.   First, the AR  t-test has been suggested for use in
public comment and was  recommended subsequently for use in a memorandum
from Skinner in November,  1983.   Also, the AR t-test removes the heavy
influence that split  sample or replicate variability exerts on the overall
estimate of variability in the background data.  It has been suggested
that the AR t-test may  help alleviate statistical contributions to the
problem of incorrect  indication  of contamination.
Methodology Used  to Analyze  the  First Year's Data
     Similar to the CABF t-test  the  background mean and variance must be
calculated.  This is  done  by first averaging the replicate measurements
and then using these  replicate averages to calculate the background mean
and variance as described  below.
Background Mean:

                                 Pb
                                ^    *,   
-------
Methodology Used to Analyze Data Collected After the First Year
     The requirements and objectives of sampling after the first year are
the same regardless of the test being applied.  For the AR t-test only the
average concentration for each well (xm) is used in the calculation of
the t-test.  A description of the sampling requirements and method for
calculating Xm are described in the prior section for the CABF test.  No
variance is computed for the monitoring data collected after the first
year when using the AR test.
     The AR t-statistic is calculated as follows:
                                    x
                            t* =     ra
     Instead of calculating the critical  t-statistic as described for  the
CABF t-test, the critical t-statistic  (t  ) is obtained directly from
                                        c
Table B-l.  The t   is  the value from Table B-l which corresponds to
                 c
M  - 1 degrees of freedom.  The t* and t  values are compared  using
the same decision rules  that  are described above for the CABF  t-test.
AN EXAMPLE OF APPLYING THE CABF AND AR T-TESTS TO A SET OF  DETECTION
MONITORING DATA COLLECTED FROM AN  INTERIM STATUS FACILITY
     This section presents statistical analyses of data collected from a
properly designed and  sampled interim  status detection monitoring system.
Table B-2 presents  an  example of total organic halide  (TOX) values
measured in parts per  billion (ppb) collected from upgradient  wells during
the first year of detection monitoring.   This detection monitoring system
consists of four upgradient wells  that were sampled bimonthly.  Four
replicate samples were taken  from  each upgradient well at each sampling.
The array of wells,  sampled bimonthly,  allows spatial and temporal
evaluation of the upgradient  ground-water quality.  The statistics
describing the first years background  data are presented in Table B-3  and
were computed using the  CABF  and AR methodology described above.
                                    B-7

-------
                           TABLE B-2

AN EXAMPLE OF TOX DATA COLLECTED DURING THE FIRST YEAR FROM AN
  UPGRADIENT  WELL SYSTEM.   THE  OVERALL  MEAN IS  65.2  ppb.   THE
 VALUE IN PARENTHESIS WAS MISSING AND WAS ESTIMATED USING THE
             METHOD DESCRIBED FOR MISSING VALUES.


Well
Month Code Replicate
1 1 A
B
C
D
REPLICATE MEAN =
2 A
B
C
D
REPLICATE MEAN =
3 A
B
C
D
REPLICATE MEAN =
4 A
B
C
D
REPLICATE MEAN =
3 1 A
B
C
D
REPLICATE MEAN =
2 A
B
C
D
REPLICATE MEAN =


TOX
Value
(ppb)
67.4
67.2
68.0
67.1
67.43
66.6
67.1
65.9
66.3
66.48
68.0
67.5
67.6
67.6
67.68
60.1
59.1
58.7
62.1
60.0
65.2
63.0
62.7
64.0
63.73
60.9
61.7
62.8
62.2
61.9
B-8
Difference
Between the
Overall Mean
and the Value
- 2.2
- 2.0
- 2.8
- 1.9
- 2.23
- 1.40
- 1.90
- 0.70
- 0.10
- 1.28
- 2.80
- 2.30
- 2.40
- 2.40
- 2.48
5.10
6.10
6.50
3.10
5.20
0.0
2.20
2.50
1.20
1.47
4.30
3.50
2.40
3.00
3.30



Squared
Difference
4.84
4.00
7.84
3.61
4.97
1.96
3.61
0.49
1.21
1.64
7.84
5.29
5.76
5.76
6.15
26.01
37.21
42.25
9.61
27.04
0.0
4.84
6.25
1.44
2.16
18.49
12.25
5.76
9.00
10.89


-------
TABLE B-2 (Continued)


Well
Month Code Replicate
3 A
B
C
D
REPLICATE MEAN =
4 A
B
C
D
REPLICATE MEAN =
5 1 A
B
C
D
REPLICATE MEAN =
2 A
B
C
D
REPLICATE MEAN =
3 A
B
C
D
REPLICATE MEAN =
4 A
B
C
D
REPLICATE MEAN =


TOX
Value
(ppb)
63.2
63.0
62.7
62.9
62.95
57.8
58.2
58.0
58.7
58.18
65.0
65.2
66.8
66.3
65.83
60.9
61.3
62.0
61.7
61.48
63.0
63.2
62.7
61.9
62.7
56.3
57.8
57.9
58.1
57.53
(Continued)
Difference
Between the
Overall Mean
and the Value
2.00
2.20
2.50
2.30
2.25
7.40
7.00
7.20
6.50
7.02
0.20
0.0
- 1.60
- 1.10
- 0.63
4.30
3.90
3.20
3.50
3.72
2.20
2.00
2.50
3.50
2.50
8.90
7.40
7.30
7.10
7.67



Squared
Difference
4.00
4.84
6.25
5.29
5.06
54.76
49.00
51.84
42.25
49.28
0.04
0.0
1.56
1.21
0.40
18.49
15.21
10.24
12.54
13.84
4.84
4.00
6.25
10.89
6.25
79.21
54.76
53.29
50.41
58.83

        B-9

-------
TABLE B-2 (Continued)


well



Month Code Replicate
"7 1



REPLICATE
2



REPLICATE
3



REPLICATE
4



REPLICATE
9 1



REPLICATE
2



REPLICATE
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =

TOX
Value
(ppb)
63.2
63.2
63.8
63.8
63.5
64.0
63.6
63.8
64.0
63.85
65.6
67.9
70.2
68.1
67.95
64.8
64.0
65.2
(64.7)
64.68
65.7
65.9
64.2
66.0
65.45
63.8
64.2
64.7
64.0
64.18
Difference
Between the
Overall Mean
and the Value
2.00
2.00
1.40
1.40
1.70
1.20
1.60
1.40
1.20
1.35
- 0.40
- 2.70
- 5.00
- 2.90
- 2.75
0.40
1.20
0.0
0.5
1.52
- 0.50
- 0.70
1.00
0.80
- 0.25
1.40
1.00
0.50
1.20
1.20


Squared
Difference
4.00
4.00
1.96
1.96
2.89
1.44
2.56
1.96
1.44
1.82
0.16
7.29
25.00
8.41
7.56
0.16
1.44
0.0
0.25
0.27
0.25
0.49
0.64
0.64
0.06
1.96
1.00
0.25
1.44
1.04
      (Continued)
        B-10

-------
TABLE B-2 (Continued)


Well



Month Code Replicate
3



REPLICATE
4



REPLICATE
11 1



REPLICATE
2



REPLICATE
3



REPLICATE
4



REPLICATE
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =
A
B
C
D
MEAN =

TOX
Value
(ppb)
65.0
65.1
65.9
66.3
65.58
61.8
61.4
61.3
51.1
61.4
69.7
72.0
71.5
70.6
70.95
73.4
75.2
76.0
75.4
75.0
71.1
74.0
72.3
73.7
72.78
72.7
74.9
73.0
73.6
73.55
Difference
Between the
Overall Mean
and the Value
0.20
0.10
- 0.70
- 1.10
- 0.38
3.40
3.80
3.90
4.10
3.80
- 4.50
- 6.80
- 6.30
- 5.40
- 5.75
- 8.20
-10.00
-10.80
-10.20
- 9.80
- 5.90
- 8.80
- 7.10
- 8.50
- 7.58
- 7.50
- 9.70
- 7.80
- 8.40
- 8.35


Squared
Difference
0.04
0.01
0.49
1.21
0.14
11.56
14.44
15.81
16.81
14.44
20.25
46.24
39.69
29.16
33.06
67.24
100.00
116.64
104.04
96.04
34.81
77.44
50.41
72.25
57.46
56.25
94.09
60.84
70.56
69.72
        B-ll

-------
                                 TABLE  B-3
     SUMMARY STATISTICS DESCRIBING THE FIRST YEAR'S BACKGROUND TOX DATA
       PRESENTED  IN  TABLE  B~2 USING  THE  COCHRAN'S  APPROXIMATION  TO THE
              BEHRENS-FISHER AND  THE AVERAGED  REPLICATE  t-TESTS
Cochran's Approximation of the
    Behrens-Fisher t-Test
Average Replicate t-Test
Total number of replicate
measurements:
         Nb = 96
Total number of replicate
averages:
         Mb = 24
Degrees of freedom:
       Nb - 1 = 95
Degrees of freedom:
       Mb - 1 = 23
Background Mean:
     nb   °b   Pb
      I    I    I  Xijk/Nb
      =l  j=l  k=l   J
Background Mean:
     nb   °b
X,. =
     (67.4 + 67.2 + 68.0 +
      67.1 + 66.6 + ... +
      73.6)/96
   = (67.43 + 66.48 + 67.68 +
       	 + 73.55)/24
Background Variance:
Background Variance:
   =  [(67.4 - 65. 2)  +
        (68.0 - 65. 2)2 +  ..
        (73.6 - 65.2)2]/95
   =  20.38
   =  [(67.43 - 65.2)  +
        (66.48 - 65.2)2 +  	
        (73.55 - 65.2)2]/23
   =  20.48
                                   B-12

-------
     After the first year four replicate measurements are collected from
each upgradient and downgradient well.  The measurements from each well
are evaluated individually by the t-test.  In this example the TOX data
from a single semiannual sampling event are presented in Table B-4.  Data
from the four background wells (1-4) which were sampled during the first
year and from the six downgradient wells (5-10) are compared using the
CABF and AR methods.
     Table B-5 presents the statistics used in conducting the CABF t-test
and Table B-6 presents the statistics used in conducting the AR t-test.
It is apparent from the comparison of these tables that there is less
computational effort required to conduct the AR t-test.  Also, notice in
Table B-5 that the CABF test indicated that well 5 had significantly
larger concentrations than the background data (because t* > t ), but
that the results of the AR test presented in Table B-6 indicated no
significant difference.  The reason that the CABF test indicated a
significant difference is because the variance among the replicate samples
in well 5 as shown in Table B-4 was larger than any other well.
     Table B-7 describes specifically, using data from well 6, how to
perform the calculations for the CABF and AR t-tests for data that are
collected after the first year.
                                   B-13

-------
                         TABLE B-4

AN EXAMPLE OF TOX DATA,  TAKEN DURING A SEMI-ANNUAL SAMPLING
 EVENT,  THAT  WILL BE  USED TO  COMPARE WITH THE BACKGROUND TOX
            DATA MEASURED DURING THE FIRST YEAR.


Location of
the Well
Upgradient























Downgradient






Well
Code Replicate
1 A
B
C
D

REPLICATE MEAN =
2 A
B
C
D

REPLICATE MEAN =
3 A
B
C
D

REPLICATE MEAN =
4 A
B
C
D

REPLICATE MEAN =
5 A
B
C
D
REPLICATE MEAN =

TOX
Value
(ppb)
64.8
64.2
65.0
64.7

64.68
65.7
65.3
65.6
65.1

65.43
64.8
65.2
64.9
65.0

65.43
65.3
65.3
65.3
65.2

65.28
68.4
69.7
68.6
67.7
68.6
Difference
Between the
Overall Mean
and the Value
- 0.12
0.48
- 0.32
- 0.02


- 0.27
0.13
0.17
0.33


0.18
0.22
0.08
0.02


- 0.02
- 0.02
- 0.02
0.08


0.20
- 1.10
0.0
0.90



Squared
Difference
0.0625
0.1225
0.2025
0.0225
2
s = 0.3476
0.0729
0.0169
0.0289
0.1089
2
S2 = 0.2276
0.0324
0.0484
0.0064
0.0004
2
S3 = 0.0876
0.0004
0.0004
0.0004
0.0064
2
s. = 0.0076
4
0.0400
1.2100
0.0
0.8100
s^ = 2.0600
                             (Continued)
                           B-14

-------
TABLE B-4 (Continued)


Location of Well
the Well Code Replicate
Downgradient 6 A
B
C
D

REPLICATE MEAN =
7 A
B
C
D

REPLICATE MEAN =
8 A
B
C
D

REPLICATE MEAN =

9 A
B
C
D

REPLICATE MEAN =

10 A
B
C
D

REPLICATE MEAN =

TOX
Value
(ppb)
66.3
66.2
65.7
66.8

66.25
64.7
65.3
65.0
65.1

65.03
64.2
64.5
64.3
64.3

64.33

66.7
63.4
65.2
65.7

65.25

62.8
63.4
63.3
63.2

63.18
Difference
Between the
Overall Mean
and the Value
- 0.05
0.05
0.55
- 0.55


0.33
0.27
0.03
0.07


0.13
- 0.17
0.03
0.03



1.45
1.85
0.05
- 0.45



0.38
- 0.22
- 0.12
- 0.02




Squared
Difference
0.0025
0.0025
0.3025
0.3025
2
s, = 0.6100
D
0.1089
0.0729
0.0009
0.0049
2
s? = 0.1876
0.0169
0.0289
0.0009
0.0009
2
s* = 0.0476
8
2.1025
3.4225
0.0025
0.2025
2
s. = 0.1876
9
0.1444
0.0484
0.0144
0.0004
2
SIQ = 0.2076
         B-15

-------



























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B-16

-------
                      TABLE B-6

  A SUMMARY OF THE  AVERAGED REPLICATE  t-TEST  APPLIED
   TO THE TOX DATA PRESENTED IN TABLES B-2 AND B-4
Location of
the Well
Upgradient



Downgradient





Well
Code
1
2
3
4
5
6
7
8
9
10
xra ~ xb
- 0.65
0.23
- 0.22
0.08
3.40
1.05
- 0.17
- 0.87
0.05
- 2.02
t*
- 0.117
0.052
-0.050
0.018
0.767
0.237
- 0.038
- 0.196
0.011
0.456
tc (o = .01,23)  = 2.500
      - l/Mb = 4.526-^1-1/24 = 4.431
                         B-17

-------
                                 TABLE  B-7
    A COMPARISON OF THE  COCHRAN'S APPROXIMATION OF  THE  BEHRENS-FISHER AND
    THE  AVERAGED REPLICATE  t-TEST METHODS  APPLIED TO  DATA  COLLECTED AFTER
      THE FIRST YEAR OF MONITORING FROM DOWNGRADIENT MONITORING WELL 6
Cochran's Approximation of the
    Behrens-Fisher t-Test
 Average Replicate t-Test
The mean (Xm) is:
The mean (Xm) is:
_
X  =  I   X.  /N
 m    _    km  m
     K "~ L
_     m
X  =  I   X,/N
 m    ^    km  m
   = 66.3 + 66.2 + 65.7 + 66.8/4
   = 66.25
   = 66.3 + 66.2 + 65.7 + 66.8/4
   = 66.25
The variance (s ) is:
               m
      m
                 -  2
           (Xkm ' V /Nm
No variance is computed for the
monitoring data collected after
the first year when using the AR
t-test
   =  (66.3 - 66.25)2 + (66.2 - 66.25)2 +
      (65.7 - 66.25)2 + (66.8 - 66.25)2/4-l
   =  0.6100
The test statistic  (t*) is:
The test statistic  (t*)  is:
t* =
         Nm   Nb
t* =
                                                        - 1/M
       1.05
      0.6040
             =  1.738
           1.05
                      =  0.237
      4.526
                                 (Continued)
                                   B-18
                                                          -  1/24

-------
                            TABLE  B-7  (Continued)
Cochran's Approximation of the
    Behrens-Fisher t-Test
                                Average Replicate t-Test
The critical t value (tc) is:

     W t  + W.t.
      mm    b b
 c     W  + Ww
        m    b

   _ (.15525H4.541) + (2.123)(2.371)
               .1525 + .2123
                               The critical t value (tc) is
                               obtained from the one-tailed
                               t-table (Table B-l) with Mb~l
                               degrees of freedom.
                               t  =2.500
     1.1959
     0.3648
= 3.278
Decision of whether significantly
larger concentrations have been
measured in the monitoring well
under evaluation.
                               Decision of whether significantly
                               larger concentrations have been
                               measured in the monitoring well
                               under evaluation.
One-tailed:
                               One-tailed:
•  If t* > tc then significantly
   larger concentrations are
   indicated.
                                  If t* > tc then significantly
                                  larger concentrations are
                                  indicated.
   t* = 1.738 < tc = 3.278 there-
   fore no significant differences
   were indicated.
                               •  t* = 0.237 < tc = 2.500 there-
                                  fore no significant differences
                                  were indicated.
                                   B-19

-------
                APPENDIX C

DESCRIPTION OF SELECTED GEOPHYSICAL METHODS
        AND ORGANIC VAPOR ANALYSIS

-------
                                APPENDIX C
          SELECTED GEOPHYSICAL METHODS AND ORGANIC VAPOR ANALYSIS
     This Appendix is a presentation of several investigative techniques
capable of augmenting data gathered from boreholes and ground-water
monitoring wells.  The five methods are:
     1.  Ground Penetrating Radar (GPR)
     2.  Electromagnetic Conductivity (EM)
     3.  Resistivity
     4.  Seismic Refraction/Reflection
     5.  Organic Vapor/Soil Gas Analysis
     The summaries of EM and resistivity focus on surficial and not
borehole methods.  Although surficial and borehole techniques operate
under the same physical principles, the reader should be aware that
surficial and borehole techniques have different characteristics.
Surficial methods can be undertaken without regard to the number of
location or boreholes therefore providing a great deal of flexibility
to the investigation without disturbing the subsurface.  Borehole EM and
resistivity, however, offer a much higher degree of resolution at depth
in the vicinity of a single borehole or between two or more.
     The effectiveness of geophysical methods and organic vapor/soil
gas analysis increases if several techniques are used conjunctively.
For instance, EM, resistivity and organic vapor analysis are highly
correlative in the field where organic contamination exists.
                                   C-l

-------
GROUND PENETRATING RADAR (GPR)*
     Ground penetrating radar (GPR) uses high frequency radio waves to
acquire subsurface information.  From a small antenna which is moved
slowly scross the surface of the ground, energy is radiated downward into
the subsurface, then reflected back to the receiving antenna, where
variations in the return signal are continuously recorded; this produces
a continuous cross-sectional "picture" or profile of shallow subsurface
conditions.  These responses are caused by radar wave reflections from
interfaces of materials having different electrical properties.  Such
reflections are often associated with natural geohydrologic conditions
such as bedding, cementation, moisture and clay content, voids, fractures,
and intrusions, as well as man-made objects.   The radar method has been
used at numerous HWS to evaluate natural soil and rock conditions, as
well as to detect buried wastes.
     Radar responds to changes in soil and rock conditions.  An interface
between two soil or rock layers having sufficiently different electrical
properties will show up in the radar profile.  Buried pipes and other
discrete objects will also be detected.
     Depth of penetration is highly site-specific, being dependent upon
the properties of the site's soil and rock.  The method is limited in
depth by attenuation, primarily due to the higher electrical conductivity
of subsurface materials.  Generally, better overall penetration is
achieved in dry, sandy or rocky areas; poorer results are obtained in
moist, clayey or conductive soils.  However,  many times data can be
obtained from a considerable depth in saturated materials, if the
specific conductance of the pore fluid is sufficiently low.  Radar
penetration from one to ten meters is common.
*GPR has been called by various names:  ground piercing radar, ground
 probing radar and subsurface impulse radar.  It is also known as an
 electromagnetic method (which in fact it is); however, since there are
 many other methods which are also electromagnetic, the term GPR has come
 into common use today, and will be used herein.
                                    C-2

-------
     The continuous nature of the radar method offers a number of
advantages over some of the other geophysical methods.  The continuous
vertical profile produced by radar permits much more data to be gathered
along a traverse, thereby providing a substantial increase in detail.
The high speed of data acquisition permits many lines to be run across a
site, and in some cases, total site coverage is economically feasible.
Reconnaissance work or coverage of large areas can be accomplished using
a vehicle to tow the radar antenna at speeds up to 8 KPH.  Very high
resolution work or work in areas where vehicles cannot travel can be
accomplished by towing the antenna by hand at much slower speeds.
Resolution ranges from centimeters to several meters depending upon the
antenna (frequency) used.
     Initial in-field analysis of the data is permitted by the picture-
like quality of the radar results.  Despite its simple graphic format,
there are many pitfalls in the use of radar, and experienced personnel
are required for its operation and for the interpretation of radar data.
     Radar has effectively mapped soil layers, depth of bedrock, buried
stream channels, rock fractures, and cavities in natural settings.
     Radar applications to HWS assessments include:
     •  Evaluation of the natural soil and geologic conditions.
     •  Location and delineation of buried waste materials, including
        both bulk and drummed wastes.
     •  Location and delineation of contaminant plume areas.
     •  Location and mapping of buried utilities (both metallic and
        non-metallic).
     The radar system discussed in this document is a readily available
impulse radar system.  Continuous wave (CW) or other impulse systems
exist,  but they are generally one of a kind, being experimental instru-
ments,  and are not discussed here.
                                    C-3

-------
     Figure C-l shows a simplified block diagram of a radar system.
The system consists of a control unit, antenna, graphic recorder, and
an optional magnetic tape recorder.  In operation, the electronics are
typically mounted in a vehicle.  The antenna is connected by a cable by
hand.  System power is usually supplied by a small gasoline generator.
Various antennas may be used with the system to optimize the survey
results for individual site conditions and specific requirements.
                                     C-4

-------
                                                 GRAPHIC  RECORDER
ANTENNA
CONTROLLER
           5-300 Meter
              Cable
  Radar
  Waveform
                                    O
                                    O
                                                   TAPE RECORDER
                                           GROUND SURFACE
                       SOIL
           i    I    \
                     ROCK
                          FIGURE C-l

       BLOCK DIAGRAM OF GROUND PENETRATING RADAR SYSTEM.
      RADAR WAVES ARE REFLECTED FROM SOIL/ROCK INTERFACE.
                              C-5

-------
ELECTROMAGNETICS (EM)*
     The electromagnetic (EM) method provides a means of measuring the
electrical conductivity of subsurface soil, rock and ground water.
Electrical conductivity is a function of the type of soil and rock, its
porosity, its permeability, and the fluids which fill the pore space.  In
most cases, the conductivity (specific conductance) of the pore fluids
will dominate the measurement.   Accordingly, the EM method is applicable
both to assessment of natural geohydrologic conditions and to mapping of
many types of contaminant plumes.  Additionally, trench boundaries,
buried wastes and drums, as well as metallic utility lines can be located
with EM techniques.
     Natural variations in subsurface conductivity may be caused by
changes in soil moisture content, ground water specific conductance,
depth of soil cover over rock,  and thickness of soil and rock layers.
Changes in basic soil or rock types,  and structural features such as
fractures or voids may also produce changes in conductivity.  Localized
deposits of natural organics, clay, sand, gravel, or salt rich zones will
also affect subsurface conductivity.
     Many contaminants will produce an increase in free ion concentration
when introduced into the soil or ground water systems.  This increase
over background conductivity enables detection and mapping of contaminaed
soil and ground water at HWS, landfills, and impoundments.  Large amounts
*The term electromagnetic has been used in contemporary literature as a
 descriptive term for other geophysical methods, including GPR and metal
 detectors which are based on electromagnetic principles.  However, this
 document will use electromagnetic (EM) to specifically imply the measure-
 ment of subsurface conductivites by low-frequency electromagnetic induc-
 tion.  This is in keeping with the traditional use of the term in the
 geophysical industry from which the EM methods originated.  While the
 authors recognize that there are many electromagnetic systems and manu-
 facturers, the discussion in this section is based solely on instruments
 which are calibrated to read in electrical conductivity units and which
 have been effectively and extensively used at hazardous waste sites.
                                    c-6

-------
of organic fluids such as diesel fuel can displace the normal soil
moisture, causing a decrease in conductivity which may also be mapped,
although this is not commonly done.  The mapping of a plume will usually
define the local flow direction of contaminants.  Contaminant migration
rates can be established by comparing measurements taken at different
t imes.
     The absolute values of conductivity for geologic materials (and
contaminants) are not necessarily diagnostic in themselves, but the
variations in conductivity, laterally and with depth, are significant.
It is this variation which enables the investigator to rapidly find
anomalous conditions.
     Since the EM method does not require ground contact, measurements
may be made quite rapidly.  Lateral variations in conductivity can be
detected and mapped by a field technique called profiling.  Profiling
measurements may be made to depths ranging from 0.75 to 60 meters.
Instrumentation and field procedures have been developed recently which
make it possible to obtain continuous EM profiling data to a depth of
15 meters.  The data is recorded using strip chart and magnetic tape
recorders.  This continuous measurement allows increased rates of data
acquisition and improved resolution for mapping small geohydrologic
features.  Further, recorded data enhanced by computer processing has
proved invaluable in the evaluation of complex hazardous waste sites.
The excellent lateral resolution obtained from EM profiling data has been
used to advantage in efforts to outline closely-spaced burial pits, to
reveal the migration of contaminants into the surrounding soil, or to
delineate fracture patterns.
     Vertical variations in conductivity can also be detected by the EM
method.  A station measurement technique called sounding is employed for
this purpose.  Data can be acquired from depths ranging from 0.75 to
60 meters.  This range of depth is achieved by combining results from
                                   C-7

-------
a variety of EM instruments, each requiring different field application
techniques.  Other EM systems are capable of sounding to depths of
1,000 feet or more, but have not yet been used at HWS and are not
adaptable to continuous measurements.
     Profiling is the most effective use of the EM method,  continuous
profiling can be used in many applications to increase resolution, data
density, and permit total site coverage at critical sites.
     At HWS  applications of EM can provide:
     •  Assessment of natural geohydrologic conditions;
     •  Locating and mapping of burial trenches and pits containing drums
        and/or bulk wastes;
     •  Locating and mapping of plume boundaries;
     •  Determination of flow direction in both unsaturated and saturated
        zones;
     •  Rate of plume movement by comparing measurements taken at
        different times; and
     •  Locating and mapping of utility pipes and cables which may affect
        other geophysical measurements, or whose trench may provide a
        permeable pathway for contaminant flow.
     This document discusses only those instruments which are designed
and calibrated to read directly in units of conductivity.
     The basic principle of operation of the electromagnetic method is
shown in Figure C-2.  The transmitter coil radiates an electromagnetic
field which induces eddy currents in the earth below the instrument.
Each of these eddy current loops, in turn, generates a secondary electro-
magnetic field which is proportional to the magnitude of the current
flowing within that loop.  A part of the secondary magnetic field from
each loop is intercepted by the receiver coil and produces an output
voltage which (within limits) is linearly related to subsurface
                                    C-8

-------
                                                   Coil
                                       SECONDARY FIELDS
                                      FROM CURRENT LOOPS
                                          SENSED BY
                                         RECEIVER COIL
                    FIGURE  C-2

BLOCK DIAGRAM SHOWING EM PRINCIPLE OF OPERATIONS
                        C-9

-------
conductivity.  This reading is a bulk measurement of conductivity; the
cumulative response to subsurface conditions ranging all the way from the
surface to the effective depth of the instrument.
     The sampling depth of EM equipment is related to the instrument's
coil spacing.  Instruments with coil spacings of 1, 4, 10, 20, and
40 meters are commercially available.  The nominal sampling depth of an
EM system is taken to be approximately 1.5 times the coil spacing.
Accordingly, the nominal depth of response for the coil spacings given
above is 1.5, 6, 15, 30, and 60 meters.
     The conductivity value resulting from an EM insruraent is a
composite, and represents the combined effects of the thickness of soil
or rock layers, their depths, and the specific conductivities of the
materials.  The instrument reading represents the combination of these
effects, extending from the surface to the arbitrary depth range of the
instrument.  The resulting values are influenced more strongly by shallow
materials than by deeper layers,  and this must be taken into
consideration when interpreting the data.  Conductivity conditions from
the surface to the instrument's nominal depth range contribute about
75 percent of the instrument'~ response.   However, contributions from
highly conductive materials lying at greater depths may have a
significant effect on the reading.
     EM instruments are calibrated to read subsurface conductivity in
millimhos per meter (mm/m).  These units are related to resistivity units
in the following manner:
                   1000/(millimhos/meter) = 1 ohm-meter
                   1000/(millimhos/meter) = 3.28 ohm-feet
                      1 millimho/meter    = 1 siemen
     The advantage of using millimhos/meter is that the common range of
resistivities from 1 to 1000 ohm-meters is covered by the range of
conductivities from 1000 to 1 millimhos/meter.  This makes conversion of
units relatively easy.
                                   C-10

-------
     Most soil and rock minerals, when dry, have very low conductivities
(Figure C-3).  On rare occasions, conductive minerals like magnetite,
graphite and pyrite occur in sufficient concentrations to greatly
increase natural subsurface conductivity.  Most often, conductivity is
overwhelmingly influenced by water content and the following soil/rock
parameters:
     •  The porosity and permeability of the material;
     •  the extent to which the pore space is saturated;
     •  the concentration of dissolved electrolytes and colloids in the
        pore fluids; and
     •  the temperature and phase state (i.e., liquid or ice) of the pore
        water.
A unique conductivity value cannot be assigned to a particular material,
because the interrelationships of soil composition, structure and pore
fluids are highly variable in nature.
     In areas surrounding HWS, contaminants may escape into the soil and
the ground-water system.  In many cases, these fluids contribute large
amouns of electrolytes and colloids to both the unsaturated and saturated
zones.  In either case, the ground conductivity may be greatly affected,
sometimes increasing by one to three orders of magnitude above background
values.  However, if the natural variations in subsurface conductivity
are very low, contaminant plumes of only 10 to 20 percent above
background may be mapped.
     In the case of spills involving heavy nonpolar,  organic fluids such
as diesel oil, the normal soil moisture may be displaced, or a sizeable
pool of oil may develop at the water table.  In these cases, subsurface
conductivites may decrease causing a negative EM anomaly.  (A negative
anomaly will occur only if substantial quantities of nonconductive
contaminants are present.)
                                   C-ll

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                                 Conductivity  (millimhos /meter)
ID'
Cloy and Marl
Loam
Top Soil
Clayey Soils
Sandy Soils
Loose  Sands
River Sand and Gravel
Glacial  Till
Chalk
Limestones
Sandstones
Basalt
Crystalline Rocks
                                 I0
10'
10'
10
                                                                  2
////////


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                                 FIGURE C-3

           RANGE OF ELECTRICAL CONDUCTIVTIBS  IN NATURAL SOIL AND ROCK.
                        (Modified After Culley et al.)
                                   C-12

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RESISTIVITY
     The resistivity method is used to measure the electrical resistivity
of the geohydrologic section which includes the soil, rock, and ground
water.  Accordingly, the method may be used to assess lateral changes and
vertical cross sections of the natural geohydrologic settings.  In
addition, it can be used to evaluate contaminant plumes and locate buried
wastes at hazardous waste sites.
     Application of the method requires that an electrical current be
injected into the ground by a pair of surface electrodes.  The resulting
potential field (voltage) is measured at the surface between a second
pair of electrodes.  The subsurface resistivity can be calculated by
knowing the electrode separation and geometry of the electrode positions,
applied current, and measured voltage.  (Resistivity is the reciprocal of
conductivity, the parameter directly measured by the EM technique.)
     In general, most soil and rock minerals are electrical insulators
(highly resistive); hence the flow of current is conducted primarily
through the moisture-filled pore spaces within the soil and rock.
Therefore, the resistivity of soils and rocks is predominantly controlled
by the porosity and permeability of the system, the amount of pore water,
and the concentration of dissolved solids in the pore water.
     The resistivity technique may be used for "profiling" or "sounding."
Profiling provides a means of mapping lateral changes in subsurface
electrical properties.  This field technique is well suited to the
delineation of contaminant plumes and the detection and location of
changes in natural geohydrologic conditions.  Sounding provides a means
of determining the vertical changes in subsurface electrical properties.
Interpretation of sounding data provides the depth and thickness of
subsurface layers having different resistivities.   Commonly up to four
layers may be resolved with this technique.
                                   C-13

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     Applications of the resistivity method at hazardous waste sites
include:
     •  Locating and mapping contaminant plumes;
     •  Establishing direction and rate of flow of contaminant plumes;
     •  Defining burial sites by
        - locating trenches,
        - defining trench boundaries,
        - determining the depths of trenches; and
     •  Defining natural geohydrologic conditions such as
        - depth to water table or to water-bearing horizons,
        - depth to bedrock, thickness of soil, etc.
     Most dry mineral components of soil and rock are highly resistive
except for a few metallic ore minerals.  Under most circumstances, the
amount of soil/rock moisture dominates the mesurement greatly reducing
the resistivity value.   Current flow is essentially electrolytic, being
conducted by water contained within pores and cracks.  A few minerals
like clays actually contribute to conduction.  In general,  soils and
rocks become less resistive as:
     •  Moisture or water content increases;
     •  Porosity and permeability of the formation increases;
     •  Dissolved solid and colloid (electrolyte) content increases; and
     •  Temperature increases (a minor factor, except in areas of
        permafrost).
     Figure C-4 illustrates the range of resistivity found in commonly-
occurring soils and rocks.  Very dry sand, gravel, or rock as encountered
in arid or semi-arid areas will have very high resistivity.   As the empty
pore spaces fill with water, resistivity will drop.  Conversely, the
resistivity of earth materials which occur below the water table but lack
pore space (such as massive granite and limestone) will be relatively
high and will be primarily controlled by current conduction along cracks
                                   C-14

-------
                                     Resistivity (ohm-meters)
                                                  's     I04     I09
Cloy and Marl
Loam
Top Soil
Clayey  Soils
Sandy  Soils
Loose Sands
River Sand and Gravel
Glacial  Till
Chalk
Limestones
Sandstones
Basalt
Crystalline Rocks
                                  FIGURE C-4

            RANGE OF RESISTIVITIES IN COMMONLY-OCCURRING SOILS AND ROCKS
                         (Modified  after Culley et  al.)
                                    C-15

-------
and fissures in the formation.  Clayey soils and shale layers generally
have low resistivity values, due to their inherent moisture and clay
mineral content.  In all cases, an increase in the electrolyte, total
dissolved solids (TDS) or specific conductance of the system will cause a
marked increase in current conduction and a corresponding drop in
resistivity.  This fact makes resistivity an excellent technique for the
detection and mapping of conductive contaminant plumes.
     It is important to note that no geologic unit or plume has a unique
or characteristic resistivity value.  Its measured resistivity is
dependent on the natural soil and rock present, the relative amount of
moisture, and its specific conductance.  However, the natural resistivity
value of a particular formation or unit may remain within a small range
for a given area.
     Figure C-5 is a schematic diagram showing the basic principles of
operation.  The resistivity method is inherently limited to station
measurements, since electrodes must be in physical and electrical contact
with the ground.  This requirement makes the resistivity method slower
than a noncontract method such as EM.
     Many different types of electrode spacing arrays may be used to
make resistivity measurements; the more commonly used include wenner,
Schlumberger, and dipole-dipole.  Due to its simple electrical geometry,
the Wenner array will be used as an example in the remainder of this
section; however, its use is not necessarily recommended for all site
conditions.  The choice of array will depend upon project objectives and
site conditions and should be made by an experienced geophysicist.
     Using the Wenner array, potential electrodes are centered on a line
between the current electrodes; and equal spacing between electrodes is
maintained.  These "A" spacings used during HWS evaluation commonly range
from 0.3 meter to more than 100 meters.  The depth of measurement is
related to the "A" spacing and may vary depending upon the geohydrology.
                                   C-16

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                                          Current Meter
               Current  Flow
               Through  Earth
                                       	Current
                                       	Voltage
                                                               Surface
     Apparent  resistivity values using the Wenner array are calculated
from the measured voltage and current and the spacing between electrodes
as shown in the  following equation:

                              a = 2  A V/I

where  a = apparent resistivity (ohm-meters or ohm-feet)
       A = "A" spacing (meters or feet)
       V = potential (volts)
       I = current (arapers)
                               FIGURE C-5

         DIAGRAM SHOWING BASIC CONCEPT OF RESISTIVITY MEASUREMENT
                                  C-17

-------
     Current is injected into the ground by the two outer electrtodes
which are connected by cables to a DC or low-frequency AC current source.
(If true DC is used, special nonpolarizing electrodes must be used.)  The
distribution of current within the earth is influenced by the relative
resistivity of subsurface features.  For example, homogenous subsurface
conditions will have the uniform current flow distribution and will yield
a resistivity value characteristic of the sampled section.  On the other
hand, current distribution may be pulled downward by a low-resistivity
(lower than that of the surface layer, due to the influence of the lower
resistivity material at depth.
     The current flow within the subsurface produces an electric field
with lines of equal potential, perpendicular to the lines of current
(Figure C-5).  The potential field is measured by a voltmeter at the two
inner electrodes.
                                   C-18

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SEISMIC REFRACTION
     Seismic refraction techniques are used to determine the thickness
and depth of geologic layers and the travel time or velocity of seismic
waves within the layers.  Seismic refraction methods are often used to
map depths to specific horizons such as bedrock, clay layers, and water
table.  In addition to mapping natural features, other secondary
applications of the seismic method include the location and definition of
burial pits and trenches at HWS.
     Seismic waves transmitted into the subsurface travel at different
velocites in various types of soil and rock and are refracted (or bent)
at the interfaces between layers.  This refraction affects their path of
travel.  An array of geophones on the surface measures the travel time of
the seismic waves from the source to the geophones at a number of
spacings.  The time required for the wave to complete this path is
measured, permitting a determination to be made of the number of layers,
the thicknesses of the layers and their depths, as well as the seismic
velocity of each layer.  The wave velocity in each layer is directly
related to its material properties such as density and hardness.
     A seismic source, geophones, and a seismograph are required to make
the measurments.  The seismic source may be a simple sledge hammer with
which to strike the ground.  Explosives and any other seismic sources may
be utilized for deeper or special applications.  Geophones implanted in
the surface of the ground translate the received vibrations of seismic
energy into an electrical signal.  This signal is displayed on the
seismograph,  permitting measurement of the arrival time of the seismic
wave,  since the seismic method measures small ground vibrations, it is
inherently susceptible to vibration noise from a variety of natural and
cultural sources.
     At HWS,  seismic refraction can be used to define natural geohydro-
logic conditions,  including thickness and depth of soil and rock layers,
                                   C-19

-------
their composition and physical properties, and depth to bedrock or water
table.  It can also be used for the detection and location of anomalous
features, such as pits and trenches, and for evaluation of the depth of
burial sites or landfills.  (In contrast to seismic refraction, the
reflection technique, which is common in petroleum exploration, has not
been applied to HWS.  This is primarily because the method cannot be
effectively utilized at depths of less than 20 meters.)
     Although a number of elastic waves are inherently associated with
the method, conventional seismic refraction methods that have been
employed at HWS are concerned only with the compressional wave (primary
or P-wave).  The compressional wave is also the first to arrive which
makes its identification relatively easy.
     These waves move through subsurface layers.  The density of a layer
and its elastic properties determine the speed or velocity at which the
seismic wave will travel through the layer.  The porosity, mineral
composition, and water content of the layer affect both its density and
elasticity.  Table C-l lists a range of compressional wave velocities in
common geologic materials.  It can be seen from these tables that the
seismic velocities for different types of soil and rock overlap, so
knowing the velocities of these layers alone does not permit a unique
determination of their composition.   However,  if this knowledge is
combined with geologic information,  it can be used intelligently to
identify geologic strata.
     In general, velocity values are greater for:
     •  dense rocks than light rocks.
     •  older rocks than younger rocks.
     •  igneous rocks than sedimentary rocks.
     •  solid rocks than rocks with cracks or fractures.
                                   C-20

-------
                         TABLE C-l

RANGE OF VELOCITIES FOR COMPRESSIONAL WAVES IN SOIL AND ROCK
                    (After Jakosky,  1950)
Material
Weathered surface material
Gravel or dry sand
Sand (wet)
Sandstone
Shale
Chalk
Limestone
Salt
Granite
Metamorphic rocks
Velocity
305
465
610
1,830
2,750
1.830
2,140
4,270
4,380
3,050
(Meters/sec)
610
915
- 1,830
- 3,970
- 4,270
- 3,970
- 6,100
- 5,190
- 5,800
- 7,020
                            C-21

-------
     •  unweathered rocks than weathered rocks.
     •  consolidated sediments than unconsolidated sediments.
     •  water-saturated unconsolidated sediments than dry unconsolidated
        sediments.
     •  wet soils than dry soils.
     Figure C-6 shows a schematic view of a 12-channel seismic system in
use and the compessional waves traveling through a two-layered system of
soil over bedrock.  A seismic source produces seismic waves which travel
in all directions into the ground.  The seismic refraction method,
however, is concerned only with the waves shown in Figure C-6.  One of
these waves, the direct wave, travels parallel to the surface of the
ground.  A seismic sensor (geophone) detects the direct wave as it moves
along the surface layer.  The time of travel along this path is related
to the distance between the sensor and the source and the material
composi;., the layer.
     If a denser layer with a higher velocity, such as bedrock, exists
below the surface soils, some of the seismic waves will be bent or
refracted as they enter the bedrock.  This phenomenon is similar to the
refraction of light rays when light passes from air into water and is
described by Snell's law.  One of these refracted waves, crossing the
interface at a critical angle, will move parallel to the top of the
bedrock at the higher velocity of the bedrock.  The seismic wave
travelling along this interface will continually release energy back into
the upper layer by refraction.  These waves may then be detected in the
surface at various distances from the source (Figure C-6).
     Beyond a certain distance (called the critical distance), the
refracted wave will arrive at a geophone before the direct wave.  This
happens even though the refraction path is longer, because a sufficient
portion of the wave's path occurs in the higher velocity bedrock.
                                   C-22

-------
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C-23

-------
Measurement of these first arrival times and their distances from the
source permits calculation of layer velocities, thicknesses and bedrock
depth.  Application of the seismic method is generally limited to
resolving three to four layers.
     The preceding concepts are based upon the fundamental assumptions
that:
     1.  Seismic velocities of geologic layers must increase with depth.
         This requirement is generally met at most sites.
     2.  Layers must be of sufficient thickness to permit detection.
     3.  Sesimic velocities of layers must be sufficiently different to
         permit resolution of individual layers.
There is no way to establish from the seismic data alone whether a hidden
layer (due to 1 and 2 above) is present; therefore, correlation to a
boring log or geologic knowledge of the site must be used to provide a
cross check.  If such data is not available, the interpreter must take
this into consideration in evaluating the data.
     Variations in the thickness of the shallow soil zone, inhomo-
geneities within a layer, or irregularities between layers will often
produce geologic scatter or anomalies in the data.  This data scatter
is useful information, revealing some of the natural variability of the
site.  For example, a zone containing a number of large boulders in a
glacial till deposit will yield inconsistent arrival times, due to
variable seismic velocities between the boulders and the clay matrix.
An extremely irregular bedrock surface as is often encountered in karst
limestone terrain, likewise, will produce scatter in the seismic data.
     The seismic refraction technique uses the equipment shown in
Figure C-6.  The seismic source is often a simple ten-pound sledge hammer
or drop weight which strikes the ground, generating a seismic impulse.
Explosives and a variety of other excitation sources are also used for
the greater energy levels rquired for information at deeper layers.
                                   C-24

-------
     Seismic waves are detected by geophones implanted in the surface of
the ground at various distances from the source.  The geophone converts
the seismic wave's mechanical vibration into an electrical signal in a
manner similar to that of a microphone.  This signal is carried by cable
to the seismograph.
     The seismograph is an instrument which electronically amplifies and
then displays the received seismic signal from the geophone.  The display
may be a cathode ray tube, a single-channel strip chart, or a thermal
printer, commonly used on multi-channel systems.  The identification and
measurement of the arrival time of the first wave from the seismic source
is obtained from this presentation.  The time is measured in milliseconds,
with zero time or start of trace intitiated by the source, which provides
a trigger signal to the seismograph.
     Travel time is plotted against source-to-geophone distance producing
a time/distance (T/D) plot.
     •  The number of line segments indicates the number of layers.
     •  The slope of each line segment is inversely proportional to the
        seismic velocity in the corresponding layer.
     •  Break points in the plot (critical distance, X) are used with the
        velocities to calculate layer depth.
     The seismic line must be centered over the required information area
and overall line length must be three to five times the maximum depth of
interest.  Resolution is determined by the geophone spacing.  Spacings of
3 to 15 meters are commonly used;  however, closer spacings may be
necessary for very high resolution of shallow geologic sections.
                                   C-25

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ORGANIC VAPOR/SOIL GAS ANALYSIS
     Organic contaminant vapors present in the vadose zone may be
assessed using a variety of techniques.  One method is the use of organic
vapor detectors such as OVAs, explosimeters and Draeger tubes to detect
volatile organics.  Two major strategies may be adopted, jointly or
separately, depending on whether wells are in place at the time of
investigation:
     1.  Monitoring the well head space.
     2.  Monitoring the vadose zone directly by lowering a probe into
         shallow, hand-augurred holes.
     Gaseous sample constituents can be identified in detail using a
portable gas chromatograph.  An alternative methodology is an analysis of
soil gas.  Under this methodology, a ten-liter sample of soil gas is
drawn through a probe which is mechanically driven into the ground to a
depth of about ten feet.  Two cubic centimeters of gas are injected into
a portable gas chromatograph to ascertain its organic constituents.  It
is useful to know what class of organics is present in order to choose
the gas chromatography method which provides the highest resolution,
i.e., photoionization/aromatics, electron-capture/halogenated hydro-
carbons.  The 2 cc sample is injected by syringe to the gas chromatograph
through a dewatering napthalon tubing.  This method is limited in two
major ways:
     1.  Coarse, pebbly/cobbly strata prevent penetration of the probe,
         in which case holes may be hand-augured.
     2.  The presence of shallow, saturated zones, especially low
         permeability formations severely restricts the development of a
         gas envelope and thus limits the applicability of the method.
         Soil gas analysis is a vadose zone monitoring technique and
         cannot be used effectively where the water table or saturation
         is shallow.
     Organic vapor/soil gas analysis is most effective when used in
conjunction with other investigative methods.  Although it provides an
                                   C-26

-------
analysis of the volatile organics and thus provides a preliminary
characterization of the subsurface contamination, it is limited to a
fraction of the total hazardous constituents and needs augmentation.
                                   C-27

-------
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-------
                         CHAPTER 3

                       GROUND WATER
DRAFT
 I.  INTRODUCTION

     The essential objective of the PA/SI in relation to ground
 water is to determine for each solid waste management unit at the
 RCRA facility whether or not the unit has released or is likely to
 have released hazardous wastes or constitutents to the uppermost
 aquifer.  For units which have identified releases/ or for which
 there is a substantial likelihood of a release, further investigations
 will be required of the owner/operator to actually determine the
 extent of a release(s) and/or to characterize the release and begin
 the development of a program of corrective measures.

     The determination as to the need for further ground water
 investigations at a unit must be made on a case-by-case basis,
 considering the various relevant factors which are unique to each
 unit.  For some units the potential for ground water contamination
 will not be difficult to assess, and the determination of need for
 further investigations will be relatively straightforward.  For
 other units, however, the potential for contamination will be less
 than obvious, and the determination will necessarily be based on
 judgement of the individuals conducting and reviewing the results
 of the PA/SI, combined in some cases with actual sampling and
 analysis.

     In making determinations from the PA/SI as to the need for
 additional ground water investigations, it must be recognized that
 comprehensive ground water investigations will typically require a
 considerable investment of time and resources for both the owner/
 operator in conducting the actual investigations,  and for the
 reviewing agency in reviewing technical plans, hydrogeologic data
 and analytical results.  This economic and resource concern must be
 balanced against the essential mandate of protecting human health
 and the environment;  i.e.., the need to identify ground water
 contamination and begin the process of cleaning up that contamination.

    It is therefore the dual function of the PA/SI to conservatively
 identify situations which merit additonal ground water investigations,
 and at the same time to avoid requiring unnecessary investigations.


 II.  UNITS OF CONCERN

     Each solid waste managment unit at the facility should be
 evaluated for its potential to be causing or to have caused ground
water contamination.   The exception to this is for "regulated
 units";  i.e., landfills,  surface impoundments,  waste piles and land
 treatment units which received wastes after July 26, 1983.  Releases
 to ground water from regulated units must be addressed in permits
 according to the requirements of Subpart F of Part 264 (or cor-

-------
responding State regulations), rather than through the §3004(u)
authority.  Thus, investigation of ground water contamination  from
regulated units will not be"part of the PA/SI.


III.  EXISTING GROUND WATER MONITORING SYSTEMS

     An assessment should be made in the preliminary assessment and
the site investigation of any existing ground water monitoring
systems at the facility which may be capable of detecting releases
from solid waste management units (swmus) at the facility.  Some
swmus may have a monitoring system installed specifically for  the
unit.  In other cases a monitoring system placed at a regulated
unit(s) or other units may also be capable of monitoring the swmu.
An example of this might be a closed landfill cell surrounded  by
several active cells.

     If it is determined from the preliminary assessment that  an
existing system is installed at a swmu, that system should be
carefully examined for its technical adequacy [i.e., to what extent
does it meet the general performance standard in §264.97(a)].
Information required to assess the adequacy of an existing monitoring
would include:  detailed information on geology and hydrogeology at
the unit, waste characteristics, background and downgradient water
quality data, boring logs, well design information, and sampling and
analytical procedures.

     In evaluating whether a monitoring system which was installed
at another unit(s) (such as a regulated unit) may be capable of
also detecting releases from a swmu, particular attention must be
paid to such features as proximity of the swmu to the regulated
unit, the direction of ground water flow, well locations in relation
to the swmu, and whether or not the appropriate constituents are
being monitored for the wastes in the swmu.  Figure 3-1 provides a
graphic illustration of three different situations in which existing
monitoring systems at regulated units may or may not also adequately
monitor a swmu.

     I fan existing ground water monitoring system and program of
sampling and analysis is determined to be adequate to detect releases
to ground water from the solid waste management unit, and recent
analytical data (e.g., within the past three months) indicate that
there have been no releases, no further investigations should be
required of the owner/operator.  If the existing system is not
adequate, and the investigator determines that there is a likelihood
of ground water releases from the unit (see below), the owner/operator
should be required to conduct additional investigations as necessary,
and install additional monitoring wells and/or analyze for more or
different constituents, as part of the remedial investigation phase.
Phase II of the technical guidance will address design of appropriate
monitoring systems and analytical programs for solid waste management
units.

     There may be situations where existing monitoring systems are
adequate to detect contamination from the unit and no contamination

                             -2-

-------
                       FIGURE  3-1

                   MONITORING WELL  LOCATION
Case One
\U
V O WMA
° (* ~^\
1 RU 	 RU T
SWMU • T
1 r I
1 RU RU 9
1 t
v X
No new wells may be
neaded for SWMU if all
units are closely spaced.
Case Three
/ WMA
\ f~\ 1 1 — — — ^^
' CL'MTT ' ^-J 1 ' 1
• 5UMU ^ . 	 I
' / ' 	 •-,
\ 	 	 / / . '
----- /o : w, t
u/ \ '"' *
^*^»_GW / r
Case Two
O
/
1
\
Wei
no t
for
to
rem
\
	 	 -> \ GW .
SWMU ' il O
	 | * WMA
* u f •
Is for RUs ' ' ' j
adequate 1 f A
SWMU due | RU ^
geographic 	 [ *
o teness . '
1 RU
--•
Key
SWMU -
RU -
WMA -
O-
• -
->vGW
^s^-^ m
solid waste manage-
ment unit
regulated unit
waste management
area
background monitoring
well
downgradient moni-
tor ing well
ground-water flow
d i rec tion
New wells needed for SWMU  due
to presence of a ground-wter
d Ivide.
                                  Note:   Drawings not to scale
                         -3-

-------
has yet been evidenced, but based on the type of unit, its design,
the wastes managed or other factors, there is a likelihood of a
ground water release in the future.  In such situations, the owner/
operator should be required (as a permit condition, if -the facility
is permitted) to maintain the system and carry out an appropriate
sampling/analysis program.


IV.  UNIT ASSESSMENT FOR GROUND WATER

     Each swmu at the facility which is not adequately monitored by
an existing ground water monitoring system, and which contains or
has contained wastes capable of releasing hazardous constituents to
ground water, must be assessed to determine the likelihood of
ground water releases, and thus the need for further ground water
investigations.  This unit assessment will be based on the information
gathered in the preliminary assessment, inspection of the unit
during the site inspection, and other information generated as
necessary.  The unit assessment should be made based on the following:

     o An understanding of the overall potential of the unit to
       cause ground water releases;

     o An understanding of the primary mechanisms by which releases
       may occur from the unit;

     o An assessment of unit-specific factors which, singly or in
       combination, indicate the relative likelihood of ground water
       releases from the unit; and

     o Exposure potential.

     A discussion of each of these elements of the unit assessment
follows.
V.  POTENTIAL FOR AND MECHANISMS OF GROUND WATER RELEASES

     The general potential for ground water contamination from a
swmu is, to a great extent, dependent upon the nature and function
of the unit.  This is reflected in RCRA hazardous waste regulations.
For example, ground water monitoring is not a requirement for
container storage units, while with few exceptions monitoring is
required for landfills.  It is thus necessary, in making an assessment
of the likelihood of ground water releases from a unit, to first
consider the relative potential of the unit to release.  Table 3-1
presents a generalized ranking, in rough descending order, of the
different types of swmus and their overall potential for causing
ground water contamination, and a listing of the most common mechanisms
by which ground water releases can occur from each unit type.
Section VIII of this chapter also provides for each type of unit
examples of units which would and which would not merit further
ground water investigations.
                              -4-

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         TABLE 3-1.  UNIT POTENTIAL FOR GROUND WATER

            RELEASES AND MECHANISMS OF RELEASE
Unit Type

Class IV Injection
  Well
Surface Impoundment
Landfill
Land Treatment Unit
Class I Injection
  Well
Underground Tank
Waste Pile
In-ground Tanks
Release Mechanism

o Wastes are injected directly into the sub-
  surface
o Escape of wastes from well casing
o Spillage or other releases from waste handling
  operations at the well head

o Migration of wastes/constituents through liners
  (if present) and soils
o Damage to liners
o Overflow events and other spillage outside the
  impoundment
o Seepage through dikes to surface and/or sub-
  surface

o Migration of leachate through liners (if present)
  and soils
o Precipitation runoff to surrounding surface
  and subsurface
o Spills and other releases outside the containment
  area from loading/unloading operations

o Migration of constituents through the unsatur-
  ated zone
o Precipitation runoff to surrounding surface
  and subsurface

o Migration of wastes from the injection zone
  through confining geologic strata to upper
  aquifers
o Escape of wastes from well casings
o Spillage or other releases from waste handling
  operations at the well head

o Tank shell failure
o Leaks from piping and ancillary equipment
o Spillage from coupling/uncoupling operations
o Overflow

o Leachate migration through liner (if present)
  and soils
o Precipitation runoff to surface/subsurface

o Overflow
o Tank wall failure
o Leaks from ancillary equipment
o Spillage from coupling/uncoupling operations
                            -5-

-------
Container Storage
  Unit
Above Ground Tank
Incinerator
o Spills from containers/container failure and
  subsequent migration through liners (if any)
  and soils
o Precipitation runoff from stora'ge areas

o Overflow
o Shel1 failure
o Leaks from ancillary equipment
o Coupling/uncoupling operations

o Spillage or other releases fro waste handling/
  preparation activities
o Spills due to mechanical failure
                               -6-

-------
     It should be understood that Table 3-1 is intended only to
provide a very theoretical sense of the relative potential of units
to cause ground water releases.  Unit-specific factors (as described
below) must be evaluated in determining whether further, ground
water investigations are needed for a particular unit.


VI.  EVALUATION OF UNIT-SPECIFIC FACTORS

     The following unit-specific factors should be evaluated in
assessing a swmu for ground water releases:

     A.  Unit design
     B.  Site geology/hydrogeology
     C.  Waste characteristics
     D.  Operational history
     E.  Physical integrity of the unit
     F.  Evidence of contamination

     In making a unit assessment attention should be paid to how
two or more of the above factors may combine to suggest whether or
not releases are have occurred.  For example, examination of an
above ground tank may reveal evidence of soil contamination ("F"
above) adjacent to the unit.  However, the operational history of
the unit ("D") reveals that the tank has been in operation for only
six months, the tank is in good condition ("E"), and records indicate
that the contamination occurred as a single, relatively small
overflow event.  In addition, the waste ("C") is known to be relatively
non-mobile, and clay soils underlie the facility, with an uppermost
aquifer that is quite deep ("B").  In this situation, the likelihood
of a release to ground water is very remote, and further investigations
would not be indicated.

    The factors listed above are discussed in more detail, as
follows:

     A.  Unit Design.  Focus of evaluation:

         o Does the unit have engineered features designed to
           prevent releases to ground water?

         o Are such features adequate?

         o Capacity and dimensions

     Examples of design features of concern for specific types
of units are given in Section VIII of this chapter.

     B.  Site Geology/Hydrogeology.  Focus of evaluation:

         o What is the potential for releases of any wastes or
           constituents from the unit to contaminate ground water,
           based on soil characteristics,  geologic formations,
           climate, aquifer location, subsurface drainage patterns,
           seasonal variations and other factors?

                             -7-

-------
     This evaluation should rely on standard geologic and hydrogeologic
principles, using whatever information  is available on the subsurface
characteristics of the site.   If information on subsurface character-
istics indicates that the potential for contamination of ground
water is very low (e.g., facility overlying thick  formation of low
permeability clay, in an arid  area with a very deep aquifer),
further ground water investigations would be needed only for units
for which other factors indicate a very high potential for causing
contamination (e.g., a Class IV injection well).   Likewise, if
ground water is particularly vulnerable (e.g., facility overlies
sandy soils and a shallow aquifer in a high recharge area), a
correspondingly low threshold  would be applied in  determining the
need for additonal ground water investigations.

     Where very little is known of a facility's subsurface
characteristics, other unit-specific factors will  need to be weighed
more heavily in making the ground water assessment.  In many cases,
evaluation of unit design and  waste characteristics alone may be
sufficient to determine that ground water investigations are
necessary, even though very little may be known about subsurface
characteristics.  An example of this could be a large, unlined
surface impoundment.

     C.  Waste Characteristics.  Focus of evaluation:

         o What is the potential for wastes managed in the unit
           to migrate to the uppermost aquifer, based on their
           concentration, physical/chemical properties, and
           behavior in water and soils?

     There is considerable variation in the relative likelihood
of different hazardous constituents to actually migrate from a
given unit through the unsaturated zone and into and through ground
water.  Many of the constituents in Appendix VIII  are essentially
insoluble in water (at neutral pH)  and/or bind tightly to soil
particles, reducing the likelihood of contamination of ground water.
The investigator should consider the potential mobility of the
waste(s)  in a unit,  in combination with other unit-specific factors.

    The relative mobility of waste constituents can be expressed by
the sorption equilibrium constant (K^).  The K
-------
where a number of wastes are present  in a unit  (e.g., in a commercial
landfill), the values given in Appendix 3-1 will have little
application.
                             •
     D.  Operational History of the Unit.  Focus of evaluation:

         o To what extent, and how, does the operational history
           of the unit indicate that  a release  to ground.water from
           the unit may have occurred?

     Operational factors which may influence the likelihood of
ground water releases may include:

     —Service life of the unit.  Units which have been managing
       wastes for long periods of time will usually have a greater
       likelihood of releases than units which  have been operating
       for short periods of time.  For example, an underground tank
       which has been in service for  six months will have a much
       smaller likelihood of leakage  due to corrosion than will a
       twenty-year old underground tank.

     —Operational status.  In some cases, the  operational status
       of a storage unit (e.g., closed, inactive, decomissioned) may
       have an effect on the relative likelihood of a ground water
       release.

     —Operating procedures.  Proper maintenance, regular inspections,
       and procedures for ensuring waste compatibility with the unit
       may provide indication that a  unit is unlikely to have released
       (this is particularly true for storage units such as tanks
       and container storage areas).  Evidence  of good operational
       practices may be available from owner/operator records,
       and/or visual observation or historical  inspection reports.
       Conversely, poor operating practices (e.g., underground
       tanks which are never leak tested or inspected internally,
       storage of open containers of wastes) may indicate relatively
       greater potential for ground water releases.

     E.'~- Physical Condition of Unit.  Focus of  evaluation:

         o Does the physical condition of the unit indicate a likeli-
           hood of releases that may contaminate ground water?

     Examples of how physical condition of certain types of units
may indicate potential for releases are given in Section VIII of
this chapter.

     F.   Evidence of Release.  Focus of evaluation:

         o Is there evidence, either visual or  from existing sampling
           data of soils and/or ground water,  which indicates that
           a release to ground water has or is  likely to have
           occurred?

         o Is additional sampling data necessary to determine the

-------
           need for further ground water investigations at the unit?
           If so, how should such sampling/analysis be conducted?

     In some cases, visual examination of a unit or the area
surrounding the unit may reveal substantial soil contamination
(e.g., discolored soil, lack of or distressed vegetation), as an
indication of possible contamination.  An organic sheen on nearby
surface water may similarly provide indication of contamination-

     At some facilities, ground water sampling data from existing
monitoring wells at the facility, or from wells or springs near the
facility may be available and may indicate the presence of hazardous
constituents which could have migrated from a unit(s) at the facility,
Such data may not be conclusive evidence of a release from any
unit, due to the variabilities inherent in ground water flow,
background ground water quality, errors or deficiencies in sampling
and analysis, and other factors.  However, if existing ground water
data does exist from nearby wells or springs, and suggests contam-
ination, even though wells may not have been placed for the purpose
of monitoring the unit(s) and relatively little may be known of
subsurface characteristics, such data should be considered a very
strong indication of the need for further, more intensive ground
water investigations for the facility.

     If, from an evaluation of all of the above factors—unit
design, site geology/hydrogeology, waste characteristics, operational
history, physical condition, and existing evidence of contamination—
it is not possible to make a reasonably assured determination as to
whether a ground water release from the unit has or is likely to
have occurred, the investigation should consider whether additional
sampling and analysis of soils and/or ground water, should be done
to enable the determination to be made.  The following are examples
of situations where additional sampling might be indicated;

     o Evaluation of unit-specific factors indicates that a release
       has probably not occurred, but there is need for an extra
       measure of certainty before a determination can be made that
       no ground water investigations are necessary.

     o The evaluation indicates a likelihood of releases to ground
       water from the unit, but more definitive evidence is necessary
       to establish the need for extensive remedial investigations
       (or immediate corrective measures).

     An illustration of a situation in which sampling would be called
for is as follows:  An outdoor, unsurfaced area at a facility was
used as a container storage area for a number of years,  but has
not been used since 1980.  The facility is located in an area with
sandy soils.   Inspection of the area reveals vegetation growing on
the area, with no visible signs of contamination.  However, a
review of the operating history of the facility indicates that
the volume of wastes stored in this location was very large, and a
number of enforcement actions for serious interim status violations
have been initiated against the facility, and State inspection
records from the late 1970's indicate generally poor housekeeping

                             -10-

-------
practices.  Because of  these uncertainties,  soil  sampling  of  the
area would be recommended.
                             «
     In some cases, sampling and,analysis of  soils may yield
sufficient evidence to  enable the investigator  to determine•the
likelihood of a release to ground water.  In  other situations,
sampling of ground water from existing nearby wells or springs
would be advisable if there is reason to believe  that constituents
from the unit could migrate to such wells or  springs.

     For any sampling of soils or ground water  conducted as part of
the site investigation, the constituents to  be  analyzed should be
those which would be expected to migrate from the unit, based on
what is known of the wastes managed in the unit.  When little is
known of the wastes managed in the unit, the  investigator  will have
to exercise judgement as to the appropriate  parameters and constit-
uents to be analyzed.

     Appendix 3-2 provides three different lists  which may be used
in determining which parameters and constituents  should be analyzed
for in ground water.  Each of the lists has been  developed using
data from monitoring data at CERCLA sites, and  as such reflects the
experience of the Agency as to the types of compounds which are
most typically found in contaminated ground water at various  types
of sites.  List A in Appendix 3-2 is a list of  basic parameters
which may be useful in providing a general indication of the  exis-
tence of contamination.  The list is analogous  to, but an  expansion
of, the four basic monitoring parameters required under interim
status.  List B provides three more specific  listings of constituents
which have typically been detected at specific  industries-metal
finishing, iron and steel manufacturing, and pesticides manufacturing.
These industry-specific lists may be used in combination with List
A if the facility is engaged in one of these  three industries.
Additional lists for specific industries are being developed.  List
C is a more complete listing of the most commonly detected constit-
uents from CERCLA sites.  This list may be used,  if necessary, as a
supplement to List A,  in situations where little  is known  of  the
wastes in the unit, and the facility is not engaged in any of the
three industries listed above.

     Actual installation of new ground water monitoring wells as
necessary will typically take place during trhe remedial investigation
phase, and will not normally be done as part of the site investigation.
The determination as to the need for additional ground water  invest-
igations at a unit should be able to be made without having to
install new wells.  However, installation of new  monitoring wells
and ground water sampling and analysis is not precluded as a part
of a site investigation.  An example of a situation in which  instal-
lation of new wells might be done is as follows:

     o Evaluation of unit-specific factors reveals that a release
       has probably not occurred, but an extra degree of certainty
       is desirable,  due to the presence of down  gradient drinking
       water wells (see Section VII on exposure potential); and

                             -11-

-------
     o A sufficient amount of  information is available on site
       hydrogeology to enable  reasonably well designed and located
       wells to be installed without substantial preliminary sub-
       surface investigations'; and

     o The wells can be installed, sampled and analyses obtained
       within a relatively short period of time.


VII. EXPOSURE POTENTIAL

     The potential for exposure of human populations to hazardous
constituents in ground water which may be occurring or could
potentially occur from releases to ground water from the facility
should be considered by the investigator in making determinations
of the need for further ground water investigations.  If the
potential for exposure to ground water contamination from a facility
is high, a greater degree of certainty will be necessary in making
determinations that further investigations are not needed at the
facility.  Likewise, if potential for exposure is low, fewer or
less extensive investigations may be required of the owner/operator.
To illustrate, information available to the investigator may reveal
that drinking water wells are  located within a relatively short
distance from the facility (e.g., 1/4 mile), and that these wells
are located down gradient from the facility and ground water flow
is relatively rapid.  In this situation, the potential for exposure
to the drinking water well users is relatively high, and a substantial
degree of certainty would therefore be needed in determining that
ground water releases are unlikely at the facility.  Thus, for an
underground tank at the facility which stores highly mobile and
toxic wastes but which would otherwise be judged unlikely to be
causing contamination (based on design, age, etc.), it may be
prudent to require in the remedial investigation phase installation
of some type of monitoring system for the tank.  Conversely,
there may be some situations in which the potential for human
exposure to ground water contamination from a unit would be
extremely low, and would thus suggest that ground water investi-
gations-for a unit might be unnecessary.


     viii.   ILLUSTRATIONS'

     As a means of illustrating and summarizing the foregoing
discussion, Table 3-2 is intended to provide specific examples of
the kinds of units which would and which would not merit remedial
ground water investigations,  based on the general potential for
contamination, unit specific factors, and exposure potential.
This table is not intended to be a complete listing of the types
of units and situations which are expected to be encountered at
RCRA-regulated facilities.   It is rather meant to give a sense of
the types of unit scenarios in which remedial investigations
generally would and would not be needed.
                              -12-

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                            TABLE 3-2.   UNIT  ILLUSTRATIONS
Unit Type
 Further Investigation
 Needed
 Further Investigation
 Not Needed
Class IV
 Injection Wells

Surface
 Impoundments
Landfills
o All  Class  IV wells
o Unlined/ active  impoundments

o Impoundments which  closed with
  wastes  in-place

o Inactive or active  clay-lined
  impoundments which  held wastes
  for more than a  very  short
  period  of time (e.g.,  >1 month)

o Small,  synthetic lined impound-
  ments with evidence or records
  of liner deterioration and/or
  rupture

o Unlined impoundments which closed
  by removal of wastes,  but at
  which no ground  water  monitoring
  system, or an inadequate system,
  is installed

o Closed/inactive  commercial land-
  fill units

o Landfill units containing sub-
  stantial quantities of municipal-
  type solid waste

o Unlined monofills of wastes with
  relatively non-mobile  constituents,
  in areas with high water tables

o Closed, clay-lined  landfill units
  containing relatively mobile
  and/or toxic containerized or
  non-containerized wastes

o Areas.of facilities with heavily
  contaminated soils resulting from
  routine, systematic and deliberate
  placement of wastes on the soil
  (e.g., wood preservative "kick-back"
  areas
                       -13-
o  None
 o  Units which  closed by removal  of
  wastes  ("clean closed")  in
  accordance with §265.228(b) or
  §264.228(a)(l) (see footnote  #1)

o Small, clay or synthetic lined
  impoundments  which held relatively
  non-mobile wastes (e.g., certain
  fly ashes) for a short period of
  time

o Impoundments  which were synthetic-
  ally or concrete lined, whose
  liners have been removed, and where
  adequate soil sampling and physical
  evidence conclusively demonstrates
  that no leakage occurred from the
  unit
o Small rubbish dumps

o Monofills of wastes having very low
  potential for migration of con-
  stituents to ground water (e.g.,
  insoluble metal salts, certain fly
  ashes), and which have been
  adequately capped or covered by
  structures, in locations where the
  uppermost aquifer would never come
  in direct contact with the wastes

o Small units containing wastes with
  relatively non-mobile constituents
  in arid areas with deep aquifers,
  which are constructed with well-
  designed liners and leachate col-
  lection systems and/or which are
  situated over relatively imperm-
  eable natural geologic formations
  (e.g., clay deposits)

-------
^Ri
 Treatment
ts
 Class  I
  Injection Wells

 Underground Tanks
Waste Piles
o Active or inactive land treatment
  units in non-arid areas on which
  substantial amounts of wastes
  have been placed
                o See footnote #2
o Units on which wastes were placed
  only once, in very small amounts,
  in an area wi'th a deep water table

o A very small (e.g., 0.1. hectare)
  experimental land treatment plot
  which was operated for a limited
  period of time, in an area with
  a deep water table, where results
  of soil testing indicate complete
  biological degradation

o See footnote #2
                o Old steel tanks (e.g., >10
                  years old)  installed without
                  external or internal coatings
                  or cathodic protection,  which
                  have not recently been leak-
                  tested or had an internal in-
                  spection by a qualified inspector

                o Steel tanks which have been in
                  frequent or constant contact with
                  ground water for a relatively
                  long period of time

                o Steel or fiberglass tanks for
                  which recent internal inspection
                  and/or leak test indicates lack
                  of tank integrity

                o Relatively new,  well designed
                  tank (e.g., cathodically protected)
                  storing highly corrosive and/or
                  highly mobile or toxic wastes, in
                  an area with high water table and
                  nearby downgradient drinking
                  water wells

                o Outdoor pile containing  relatively   o Indoor pile with no free liquids
                  mobile wastes,  not situated on a
                  liner or base,  in area with porous   o
                  soils and/or shallow aquifer
                                       o Relatively new, well designed tank
                                         (e.g., external and internal epoxy
                                         coating and cathodic protection)
                                         storing non-corrosive and/or
                                          relatively non-mobile wastes/con-
                                         stituents, not likely to come in
                                         direct contact with ground water

                                       o Tank with full secondary contain-
                                         ment (e.g., vaulted tank with
                                         leak detection system)

                                       o Tank with recent internal in-
                                         spection and/or "state of the art"
                                         leak test which indicates that the
                                         tank is sound

                                       o Relatively new (e.g., <10 years)
                                         metal tank storing compatible
                                         wastes (e.g., solvents)  in an
                                         arid area with clay soils
                    o Large outdoor pile containing wastes
                      with particularly toxic constituents,
                      with physical evidence of sub-
                      stantial migration of wastes outside o
                      the containment structure, in area
                      with nearby downgradient drinking
                      water wells
                                         Covered outdoor pile situated on
                                         impermeable (e.g.,  well engineered
                                         synthetic or concrete)  base with
                                         adequate containment system for
                                         run-on and run-off
                                                        Outdoor pile  containing  relatively
                                                        non-mobile wastes  (e.g.,  certain
                                                        fly ashes) situated  on clay  soils
                                                        in area of deep  water  table
                                           -14-

-------
     round Tanks
Container Storage
 D^t
Above Ground
 Tanks
 o Relatively old concrete tank con-
   taining  large volumes  of wastes,
   with  visible  and substantial
   deterioration of exposed walls, or
   for which  recent internal inspection
   indicates  serious cracking
   of walls or other signs of
   serious  deterioration  of
   concrete

 o Large concrete tank with no
   protective internal coating
   or liner,  holding highly toxic
   and/or mobile wastes in area
   of high  water table and
   downgradient  drinking  water
   wells

 o Tank  with  visible evidence of
   extensive  soil contamination
   fron  apparent (or recorded)
   overflow events or other oper-
   ational  or structural  failures,
   in area  with  porous soils

 o Containers  stored outdoors on
   bare  soil,  with visible  signs of
   substantial soil contamination,
   in area  of  porous soils  and/or
   shallow  aquifer

 o Outdoor  area  on which  very large
   volumes  of waste containers  have
   been  stored for relatively long
   periods  of  time (e.g., >10 years)
   with  improper  storage practices
   (e.g., open containers)  and/or
   inadequate containment structures,
   with downgradient  drinking water
  wells  and/or highly toxic/mobile
  wastes

 o Large, outdoor metal tanks
   situated on soil  surface with
   visible  structural deterioration,
  holding highly mobile and/or
   toxic wastes,  in area with shallow
   aquifer  and downgradient drinking
  water_ wells

o  Old,  outdoor tank with visible
  evidence of massive soil con-
  tamination due  to  apparent (or
   recorded) overflow events, in
  area of porous  soils
 o Relatively small  tank  with
   adequate  liner/coating,  with
   record  of  frequent  inspections
   and maintenance schedule

 o Relatively new, lined/coated
   tank  in good condition,  with no
   evidence of releases
o Indoor container area with adequate
  containment structure

o Outdoor storage area with adequate
  containment system, with no
  visible" evidence of contamination

o Relatively small outdoor area
  where waste containers were placed
  for only a short period of time,
  with no evidence of serious
  contamination
o Small, indoor tanks with secondary
  containment

o Outdoor tanks elevated above soil
  surface, with secondary containment
  structures

o Outdoor tank in good condition
  situated on concrete pad, with no
  visible or recorded evidence of
  substantial release
                                            -15-

-------
                    o Large tank situated on soil
                      surface, for which recent  internal
                      inspection indicates severe
                      corrosion on bottom,'in area of
                      vulnerable hydrogeology

Incinerators        o Outdoor incinerator with             o  Indoor  incinerator with no
                      visible evidence of surrounding         apparent evidence of significant
                      massive soil contamination              releases to outside environment
                      resulting from apparent system/
                      operation malfunction
Footnotes:

I/  For such units, monitoring data should be carefully examined for evidence of ground
    water contamination; this is of particular concern for units which stored only
    characteristic waste.

2/  Class I wells inject hazardous wastes beneath the lowermost formation containing
    an underground source of drinking water (USDW) within one quarter mile of the well
    bore.  The Agency realizes that there are concerns associated with installing
    monitoring wells (often deep into the earth's crust) to detemine whether Class I
    injections are adversely affecting USDWs, including the uppermost aquifer.  Such
    concerns include:  the length of time (e.g., hundreds or thousands of years) it
      Cy take to detect a release frcm the injection zone to the monitoring wells; and
      e risks associated with installing deep monitoring wells which could later serve
       conduits for the rise of injected waste into useable aquifers.  Therefore, the
    Agency has provided discretionary authority to the State underground injection
    control (UIC) Director to require monitoring wells only when he beieves them to
    be necessary.  In such cases the Director will prescribe the number and location
    of monitoring wells and the parameters to be analyzed.

         The Agency is gathering additional information on the fate of Class I
    injections.  For example, an evaluation will be made to develop procedures that
    can be used to identify when Class I injections have migrated  beyond their
    permitted injection zones.  Until such procedures can be developed, the Agency
    will continue to limit the circumstances under which monitoring wells will
    be required.
                                         -16-

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                         APPENDIX 3-1.   SORPTION  EQUILIBRIUM CONSTANT AS

                     EXPRESSED BY  WATER-OCTANOL  PARTITION  COEFFICIENT  (Kow)*
 WEB «BST   KAflE OF KAS7E HATERIAL
  SYS t
 75-15-0     CARBON BISULFIDE

 103-90-7    CHLOROSENZEME

 1319-77-3   CRfSOLS

 95-50-1     1,2-DICHLORDBENZENE

 75-09-2     BE7HYLENE CHLORI3E

 75-69-4     TRIWLCR3MNOFLUOROBE7HME

B-S3-1      ISOBUTYL ALCOHOL .

78-93-3     BE7HYI  E7KYL KE7CNE  •

93-95-3   ' «I7fiC8E«:E,'c

110-S6-1    FVRJDiKE'
     r
54-23-3
     TETRACHLQflOETHYLENE .

     CASS3JI TETKiCriLflfiiCE
                                      106 K CK
                                            2.S7
1.26

2.52

0.74

0.30

1.90

O.o3

Z.QZ
                 CHEM «3S7   NAKE OF KAS7E «A7ERIAL .
                  SYS t
                                                                                             LG5 K Ci
                                                            1327-53-3
                                                            13C3-23-2
542-62-1

593-31-2

502-01-3

107-20-0

544-92-3

57-12-5

460-19-5

506-77-.4

69i-23-4

492-42-2
                                                                ARSENICIVJOIIBE

                                                                AfiSENICIIIIiailDE

                                                                BARIUM CYfiMIDE

                                                                BRCflOACETOSE

                                                                CALCI'JB CYANIDE

                                                                CHLORMCETALDEHYDE

                                                                COPPER CYAK1DES

                                                                SDLUBiE CYANIDE SALTS K.C.S.

                                                                CYAN05EN  .

                                                                CHL3RINE CVhMJE
                           DIETn'ilnRSJ'iE
                                                                                                    0.40
                                                                --       r.
79-Jl-i

95-9S-4

es-Oo-2
    TRICHLDSJE'HvlESE
    "2,4,6-TRICHLOROFHE.WL

    FENTACHLQSdFKESOL
 -   ETHYLEE.'uEN'E

3-3  ALLMIflUH FHOSPHJIE

-4   ARSENIC ACID
                                            3.53

                                            5,06

                                            3.10

                                            3,34
                 10102-43-9  NITRIC CrlC;

                 10102-44-0  NI7R02EN .'13., IDE

                 1C544-72-6 "KlTRSSEfJ IIKIIE

                 75-44-5    FHCS3E,\E

                 7SQ3-51-2  FHCSPH1NE

                 15L-50-3.   FGTA3SILTI CYAMIE

                 506-61-6 -  F07AESILT1 SILVER CYflNIDE

                 536-64-9   SILVER CYANIDE
          *  Note:   Low value  indicates greater  mobility;  high  value
                       indicates  lesser  mobility

                       Expressed  in log  values

-------
CHEK  CBST    NAKE  OF  HASTE  MATERIAL
  SYS  I
 143-33-9    SODIL'n CYANIDE

 57-24-9     STRYCHNINE AND SALTS

 557-21-1    IINC CYANIDE

 75-3i-5     ACETYL CHLGSIDE

 79-10-7     ACRYLIC ACID

 93-09-9     BEHZEKEs'JLFGJIYL CHLCSIDE

-353-50-4    CARBC'IYL FL'JCRIJE

 3165-93-3    4-CHLORG-G-TCLUI2INE, HYCRSCHLGnlSE

 64-13;6"
                                                 LOS K CM
                                                 -0.05



                                                 0.39

                                                 0.19

                                                  1.93
    -04-4   HYDP.CSEN SL'LFIDE
/j
                                » T r
  -»J~fc. **t   •< i n i w  i •
636-21-5    O-T;-::':::;,E  HV:RC:HL:S

;06-t;-3    CVAfiCSEN CAO.IIIE

 7t • ^ -" ^   • * "•il T P
 TiWwa-i   nriiiiilL

3l-3i-2     Bh'.FARIM

309-uv-2    ALJSIN

ic7-:s-s    ALLYL ALCCH:L

7440-41-7   EEr.YLLI!J!1 DUST
                                                    2.05
                                                    -0.22
CHEN  A3ST    KAflE  CF  HASTE  HATERIAL
  SYS  I                     •


542-23-1     BIS- (CHLORQflETHYL) ETHER

357-57-3     BRUCINE

33-35-7     DINC3EB

60-57-1     D1ELDRIN

293-04-4     DISULFOT3N

311-45-5     DIETHYL-P-WITROPHENYL FKCSFHATE

•51-23-5     2,4-DINITF,CFK£NOL

 115-29-7     ENDOSULFAN

62-74-8-    "FLliaRSACSTjQ.ACID.KDiaa.SALT

 60-34-4 "    J1ETKYL MuRAIINE
116-06-3    AL5ICAF.S

2*3-00-0    RETKVL FAFATHIuH
                                                                           20cia-12-v   Giillufl  TE.r.uiUE
 62-32-4     FHENYL r-F.CliSIC ACETATE

 52-35-7     FAIPK'.R

 107-19-7    P5GFARSYL ALC2HOL

 2-6623-22-3  S3DIUH AZICE

 73-00-2     TETRAETHYL LEAD
                                                LQG.K.CH



                                                1.06

                                                0.10

                                                4.07
                                                                                                                            1.92
                                                                                                                            -0.71

                                                                                                                            -O.II

                                                                                                                            i.;:
                                                  1.95

                                                  -i.o?

-------
       AS5T   mi OF HASTE IWTERIAL

     S I
  7446-18-6   THALLJUHUJSUlfATE




  1314-62-1   VANADIUH  PENTOIIDE




  1314-84-7   ZINC PHOSPHIDE




  79-06-1      ACRYLAflUE




 107-13-1    ACRYLONITRJ1E




 30-07-7     HITOMYCIN  C




 62-33-3     ANILINE




 223-31-4     BENZ(C)ACRIDINE




36-53:3    "BEKZiAJASTHRACENE




50-32-3 '   c£N'ZC(A;PYR£?i£  ' _




74-33-9"    KETHYL BROMIDE



            . «MIT«».«I
            i OVi iHiiul
         .     •••«,«i.«tifcir., t  r.cinn.  ;incn



 •.•a-'/!-*     (.rinfsE'iE




 123-73-9    ;."OT3SALD£HV:-£



 so-:?-3  .   ;DT       ~-




 33-70-3     2IS£'u"CiA,H!A?iTHf!AC£N£




 139-55-?'    l.:,7,3IIBEWOPYRESE




 ?4-i:-3      i,:-DiBRcaa-:-£HLD«OFF.:FssE



 106-93-4    ETHYLEHE DItRGflllE




764-41-0    l,4-DICHLORu-2-3UT£N£




1415-30-1   N,N'-D1ETH/LHYDRAZINE
                                             O.SS




                                             0.07




                                             -:.42




                                             0.93
                                             6.16.




                                             1.09




                                             O.S7
                                          L42
                                          4.33
                                         '2.13"
1.63




1.73
                                                                     DO ABST   NAflE CF WASTE HATERIAL

                                                                      SYS t
                          36-33-1      DIETHYLSTILBESTROL




                          77-73-1      DIMETHYL SULFATE




                          123-91-1     1,4-DIGIANE




                          75-21-3      ETHYLENE OI2DE




                          110-00-9    FURAN




                         302-01-2    HYDRAZIKE




                         193-39-5    IHDENCn,2,3-CD}PYREKE




                         7439-97-6   HERCuRY




                         67-36-1    "  KETHANOL  -




                         91-SO-5      flETHAPY'RILENE "




                         56-49-5     3-flETHVtCHuLANTKSENE




                         101-14-4     4,_4-!!£THYLE.'lE-3I3-i:-DiLCWANlLIKE)



                         79-46-9  '
 930-53-2    n-N!Tf;:£";i;L;;;fiE




 82-=s-3     PEMTACHLCSCSITSOEEB:



 2355'J-S2-5  PRC-'^lCe



 30-55-3     ft£SEF.F!.'i£    '




 62-36-6     THICL'?:£A




 66-75-1      URALlL .TuSTARJ




 31-J9-6      EIHTL CAS2A3ATE  -




 13931-37-8   NI^EL




616-23-9    2,3-51CHLGRCPRu?AffCL
                                                           LOG.K.OK









                                                           3.04




                                                           0.06




                                                           -0.03




                                                           -0.77




                                                           1.34









                                                           6.62
                                                          6.93




                                                          3.?6
                                                                                                                          .4.39
                                                                                                                          4.31
                                                                                                                          -0.15
                                                                                                                         0.30

-------
CHE,". AB3T   NAJ1E OF HASTE MATERIAL
 SYS I
96-18-4     1,2,3-TRICHLOROFR3PANE

7440-36-0   ANTIrtONY

203-96-3    ACENAPHTHYLENE

2C5-97-2    BENZO(B)FLUCRANTHENE

12002-48-1  TRICHLOROBENZENE

122-39-4    DIFHENYLAfllNE

1C8-45-2    H-PHENYLENEDIAKINE

118-96-7    TNT  ..

551-C3-2   " flCEIWUBE, JJ-!AfilNOTHI3I3flETHYLl-
                                                       L36 K
    :-96-4   5-(A,1IHCr>£THYL)-3-I30:A;:LCL

504-14-5    <-AHINO?YRIEISE
1.85

3.30


3.65
-0.30
2.40
-0.87
0.88.
-0.20
-0.36
757-58-4
16752-77-5
75-55-3
86-38-4
152-16-9
298-02-2
1314-96-1
107-49-3
509-14-3
1314-32-5
12039-52-0
8001-35-2
5344-51-1    i-.3—3HLG?.urKE:i'i'L) T4iIu;j?.£A
277-97-2     C.3-DIETHYL  C-PYFAZINYL FHQSFHCS3THI3ATE

55-91-4      DIISCFRQFYL  FLU3RuPH33?HATE

60-51-5     "DI.^ETHuATE  -

541-53-7     2,4-DITH!:SIuRET

15L-56-4     A::RIDI»E

64C.-19-7.    ACETA.11JE.  :-FLL13Ra-       .  .

76-44-3      HErTACHLOR

JiC.^^.L     TC"nOTU
^8J  iw  0     4•UyrtiH
                                                        .1.15

                                                        3.33

                                                         -1.00

                                                        -0.35

                                                        .-1.10

                                                         -i.12



                                                         4.77
                                                                           CHE.1 ABST   HAflE  DF  «A2TE  MATERIAL
                                                                            SYS t
            KEIAETHYL-TETRA-FHQ3PHATE

            HETHOflYL

            2-KETHYLAZ1RIBINE

            ALPHA-NAPHTHYLTHICUREA

            OCTATITHYLFYROPHOSPHCRAfllDE

            PHORATE

            STRGNTIUil 3ULFIDE

            TETRAETHYLFYR3PHOSPHATE

            TETF.ANITRQBETHANE-

            THALLIC CHSE  "

            T»ALLIL'ntl;S£LEfJITE

            TDXftFhENE
                                               136 K CM
                                                                                         il'J^i 1C, IL1
at-a-i

75-05-3'

:3--s-3

L i  ^^_jc     * w * wf>f*\ r
61-3i~3     HHiinuLt

492-80-3    AUP.ASIHE

115-02-6    AZASEF.I.NE   '

71-43-2     BENZENE

92-S7-5     SENZID1NE   '

9B-i7r7 .    BENZOTRICHLCSIDE. -

111-44-4 .   DICHLCROETHYL ETHER

494-03-1    CHLCRNAPHAZ1NE
                                                                                                                           -0.57
                                                                                                                           1.95
                                                                                                                           6.23
                                                                                                                           0.79
4,14

1.04

-------
CHEJ1 AB5T
SYS *
117-31-7
13745-19-0
305-03-3
37-74-9
75-01-4
67-64-3
91-58-7
108-94-1
50-18-0
20830-81^3
!:<-!
W- •• i
Twvw-iO"*
91-94-1"
HAKE OF HASTE MTERIAL LOSJ.W '

BI3(2-ETHYLHEIYL)PHTHALATE *4.00
CAIC1UH CHR5HATE
CKLQRAKSaCIL
CHLOR2ANE, TECHNICAL
VINYL CHLCRIDE 1.38
CHLOROFORB 1.94
BETA-CHLGRNAPHTHALENE 4. OS
CVCLOHEIA-'iOSE 0.84
'CYCL3PJ10SPH*1IDE
OA!»s.mn • ' -
DSD .
DIALLSTE
^ Ti «»/*•'» rt^^^PiifTW**!?* * f*
J|W *^AWnCUI\UvCi^4Ai/il^C W«J™
CHE.1 S8ST
SYS 1

105-47-9
121-14-2
404-20-2
117-84-0
122-44-7
142-84-7
-421-44-7
111-54-4
96-45~-7
42-3C-0 '
50-00-0
113-74-1

KAKE OF HASTE KATERIAL

2,4-DI«ETHYLPHENOL
2,4-OINITROTOLUENE
2,6-DIKITROTOLL'EKE
CI-H-CCTVL PHTHALATE
1,2-DIPHEHYLHYORfiIIME
CIFRaPYLAHIfiE
OI-M-PftOFYLJiITRC3A«lNE
ETHYLENE-BI3-(DITHIOCASBAf!IC ACID)
'.ETRYLLH: THKMEA
ETHVL BEffiSaESiKr-BSKTE .
FORMLDEHYIE
nc« HL^Uflth.6..E

LCG.K.

2.31
2.30
2.30
"4.00
3. CO
1.47
1.42

• 0.31
0,09

s.4:
4.i7

78-37-5
40-11-7     JlBETKYLnBINGAZOBENZENE




57-97-6     7,12-DIKETHYLBENZtA)ANTHRACENE




117-73-7    3,3>-01.tE;HYLB£NZIDIM




7?-44-7     CinETHYLCARBABOtL  CHLOFISE




57-14-7.    1,1-DinETHVLHYSRAZINE   "




540-73-3    1,2-DIJiETHVLHYDRAZINE
1.94
                                               7.02





                                               2.3u"





                                               l.Gi





                                               -1.47
47-72-1     n£AACrL:=:rH^E




74-38-4     flETHTL Iu::ii




143-50-0    KEFCiE









30L-04-2    LEAD ACETATE









109-77-3    f!AO!SGNlTSILE




148-82-3    MELPHALAN




108-10-1    .1ETHYL I:3BUTYL  KETCNE
                                                                                                                      i.. "3
                                                                       -i.n
                                                                                                                      1.25

-------
   AEST   NA!1E OF HASTE flATERlAL

   t
 SO-42-4     KETHYL HETHACRYLATE



 70-25-7     N-HETHYL-H-NITRO-N-NITRaSCSUASIBINE



 56-04-2     KETHYLTHIOURAC1L



 91-20-3     NAPHTHALENE



 91-59-3     2-NAPHTHYLAMINE




 100-02-7    P-HITR3FHENDL



.924-16-3    N-NITROSC-DI-N-BUTVLA.IINE




 1116-54-7   N-HJTRQSC-SI-ETHftNCLABiNE
--
 18-
            ' K-NITR.OSG-Sr-ETHiLAHINE
 759-73-9"    N-NlTRCSO-N-ETKYLi;?,EA



 615-53-2'    N-NlTRCSG-N-flETHYLDr.ETHANE







                         -y'LF ILE
 7433'5i-4   SELE.'lIiJH Si;jL"I2E




 13E33-QO-*  STREFT:::^








 79-34-5 "    1,1,2,2-TETRACHLGRCETHANE








 rt^_'" 3    ^U5! f TP» i * l <"
-------
,cfl ASST   NAflE OF HASTE JIATER1AL             LCS K QV

SYS 4                                                  ,
72-20-8     ENDR1N



624-83-9    BETHYL ISQCYANATE                   0.39



628-34-4    HEfiCURY FULKINATE



13463-37-3  NICKEL CARBSNYL



54-11-5     NICOTINE ANB SALTS                  l.i;



100-01-6    P-NITRCAMILINE                      1.32



145-73-3    ENDOTHALL



103-S5-5    N-PHENYLTHIOUREA                    0.77



107-12-0  " PROPANENITF.ILE                  .    Q.16



630-10-4    SELErJOURcA



3oe?-24-5-   TEiRncTHfiHITHIuFYRur'KCSPKATE








514-42-3    Tr.ICHLCr.unETnni'iETHIiL               l,ai












98"36-2     nCETuFHEIfC.'iE                        1.61



09.57-T     C'CM'il  T2!nBf-r                     •*• 11
/o c/ w     fikiiiML tnL..>i«c                     ^.24



lll-il-l    EIS(2-CHL2RuETKCAt)fi£THnHE         ' 0,-SQ



1C3-60-1    EIS12-CHLCRGIS3PROPYL)  ETKES        1.43








75-^7r6 .    CHLCRAL    .  .                 -      L.66



510-15-6 -   ETHYL-4,4'-DICHL2R3BENZILATE        4.41



59-50-7     4-tHLQF.O-fl-CrE3QL                   3.16
CHE.1 A£ST   KAHE CF HASTE RATERIAL

 SYS t
                                                                       110-75-3



                                                                       74-37-3



                                                                       95-57-3



                                                                       92-B2-3



                                                                       110-92-7



                                                                       74-95-3



                                                                       84-74-2



                                                                       541-73-1



                                                                       106-46-7



                                                                       75-71-8 .



                                                                       75-I4-3  .



                                                                       156-60-5



                                                                       1IO-E3-2
            2-CHLQROETHYL 9INYL ETHER



            HETHYL CKLORJSE



            0-CHLCRCFHENOL



            CUKENE



            CYCLCHEIANE



            HETHA.NE,  DISRMO



            DIBuTYL PHTHALATE



            1,3-lICHLOROBENZENE
            CICHLK'CDIFLuuR'OKEThhiiE



            ETHANE,  L,1-D1CHLOR3-



            1,2-DICHLOROETHYLENE



            2,4-uICHL.RjrHeNuL
                                                                       1464-53-5    2.2'-3ICJ;RANE



                                                                      3235-53-2    0,0-31£ThVL-S-f;£THVL-;iTK::?HC£.:r.;:E



                                                                      84-66-2      DIETHYL  FHTHALATE



                                                                      94-53-6      OIHYDRCSAFRGIE








                                                                      S0-J5r9  .    ALPHA,Ai.FHfi-SIKETHYL£ESL-:y:SjrEftGSIlE



                                                                      131-11-3     [METHYL FHTHALATE



                                                                      141-78-6    ETHYL ACETATE
2.25




C.75



? ^?




3.77




1.42




1.54
2.08.
1  0*
1 . u«
                                                    2.?!




                                                   . i.73



                                                    t " ^
                                                    *~*v




                                                    1.56




                                                    0.71

-------
CHEH  ABST    NAUE  CF HASTE HATERIAL
  SYS  t
 140-33-5    ETHYL ACRYLATE

 60-29-7     ETHYL ETHER

 97-63-2     ETHYLflETHACRYLATE

 2C4-44-0    FLUGRANTrOE

 98-01-1     FURFURAL

 763-34-4    6LYCIDYLALIEHYDE

77-47-4     HEIACHLORQCiCLOPENTALiENE

 70-30-4     HEIACHLCRCFHENE

90C4-66-4  "IRCN DEITRAJf

    33-1  '  ISuSAFRjLE

    -27-7   LEAD PHC3FHATE    '

 103-31-8    «AL£Ii AWitDSIii
LOS K CM
1.32
0.92
1.64
4.93
1.00

4.27
*6.00

:.45

0.14
B3-44-9
109-06-3
107-10-3
104-51-4
103-46-3
81-07-2
•95-94-3
75-25-2
99-35-4
72-57-1 "
94-73-7
1333-71-7
CHEfl ABST   NAflE OF ilASTE SATERIAL  '
 SYS t
                                    PHTHALIC  ANHYDRIDE

                                    2-FICGLIIlE

                                    1-PROPANAHINE

                                    F-SEN205UINONE

                                    RE30RC1XAL

                                    SACCHARIN AND SALTS

                                    1,2,4,3-TETRACHLCROEENIENE

                                    BRGUCFCSn

                                   '.SKn-TRINITRCBENIENE

                                    TRYPAN_SLJ£



                                    HEIACKLSRSFRCFESE
LCG.K.



1.32

1.34

0.43

-0.61

•\ r^
C.Ci



5.00

2.33

1.33
134-32-7 •  1-MAPHThiLAflIKE

97-55-3     5-KITRO-Q-TDLUIDi;i£

123.-63-7    PARALIEHYIs



76-01-7     PEMTACHLC.vSETHANE

304-60-9    1,3-FENTA:;EKE

62-44-2     PHENACETIN
1.12

2.11

1.93

1.06
                                              1.S4
•4:?-;:-i   LEAD
         -   FE^RI: FE-?.:CVANI:E

-------
                 APPENDIX  3-2







LISTS OF GROUND-WATER MONITORING  PARAMETERS







              LISTS A,  B,  C

-------
                              LIST A
      Parame ter
sodium
calc i urn
ma gnes i urn
sulfa te
chloride
pH
total organic carbon
total organic halogen
total p henols
1»1,1-trichloroethene
lead
cadmi urn
Chemical Abstract System Number

           7440-23-5
           7400-70-2
           7439-95-4
           71-55-6
           7439-97-6
           7440-43-9

-------
                             LIST  Bl

                   INDUSTRY SPECIFIC PARAMETERS
                          METALFINISHING
      Parame ter
chromi urn
copper
cyan Ide
iron
zinc
trichloroethene
tetrachloroethylene
vinyl chloride
phenan threne
nickel
Chemical Abstract System Number

           7440-47-3
           7550-50-8
           57-12-5
           7439-89-6
           7440-66-6
           79-01-6
           127-18-4
           75-01-4
           85-01-8

-------
                              LIST B3

                             PESTICIDES
           Parame ter
Chemical Abstract System Number
   arsenic
   cyanide
   copper
   benze ne
   carbon tetrachloride
   chlordane
   chlorobenzene
   chloroform
   1,4-dIchlorobenzene
   2,4-dichlorophenol
   hep tachlor
   hexachlorocyclopentadiene
   methyl chloride
   methylene chloride
   4-nitrophenol
   phenol
   tetrachloroethylene
   toluene
   Manufactured pesticides*
          7440-
            57-
          7550-
            71-
            56-
            57-
            67-
           108-
           106-
           120-
            76-
            77-
            74-
            75-
           100-
           108-
           127-
           108-
•38-2
•12-5
50-8
•43-2
•23-5
•74-9
66-3
•90-7
46-7
•83-2
44-8
•47-4
87-3
•09-2
02-7
95-2
18-4
88-3
*Any specific pesticides,  residues,  off-specification products,
 or other slmiliar Items known  to  have .been  disposed of  at the
 site,  or, in the case  of  a  dedicated  facility,  known to have been
 manufactured at the site.

-------
                         LIST B2

                      IRON AND STEEL
     Parame ter
arsenic
ch romi urn
cyan ide
tin
zinc
benzene
benzo(a)pyrene
tetrachloroethylene
Chemical Abstract System Number

           7440-38-2
           7440-47-3
             57-12-5
           7440-31-5
           7440-66-6
             71-43-2
             50-32-8
            127-18-4

-------
         Parameter
bis(2-ethylhexyl)phthalate
PCB-1016
PCB-1221
PCB-1232
PCB-1248
PCB-1254
PCB-1260
PCB-1242
a rsenlc
benzene
chlorobenzene
ethyl benzene
toluene
chromium
copper
cyanide
tetrachloroethylene
vinyl chloride
trichoroe thylene
iron
ma nga ne se
naph thalene
nickel
phenan threne
phenol
zinc
                              LIST C
Chemical Abs trac t Sys tern Number

          117-81-7
          12674-11-2
          11104-28-2
          11141-16-5
          12672-29-6
          11097-69-1
          11096-82-5
          53469-21-9
          7440-38-2
          71-43-2
          108-90-7
          100-41-4
          108-88-3
          7440-47-3
          7550-50-8
          57-12-5
          127-18-4
          75-01-4
          79-01-6
          7439-89-6
          7439-96-5
          91-20-3
          7440-02-0
          85-01-8
          108-95-2
          7440-6-6

-------
                           SECTION ONE

                   PLANNING AND CONDUCTING THE
                        SITE INVESTIGATION
I.   INTRODUCTION

     The site investigation (SI) is the second phase in evaluating

SWMU's for releases to the environment.  The SI builds upon the

data collected during the preliminary assessment (PA) and in

general involves collecting new information through visual observa-

tion.  Where appropriate/ the SI can also involve sample collection

and analysis.

     The purpose of an SI is to:  (1) identify units/facilities

that pose no problem, (2) prioritize facilities for further in-

vestigation, and (3) identify the scope of subsequent remedial

investigations or immediate corrective action.  This will be

accomplished by evaluating the potential for exposure to humans

and the environment via surface water, ground water, air, soil,

and subsurface gas.

     As a rule, the SI takes considerably more time than the PA

to complete.  Unlike the PA which involves mostly desk work, the

SI involves both desk and field work.

     The scope of the SI involves collecting additional data

through a comprehensive visual survey and, at some facilities,

sample collection.
                               1-1

-------
      This chapter of the Corrective Action Guidance will address



 the overall process involved in conducting a SI—beginning with



 supplementary background data collection through writing a final



 SI report.   Each section of this Chapter will discuss the various



 steps involved in performing an SI.  These steps are identified



 in Figure 1.   The evaluation stage will not be discussed in



 this chapter.  It is the subject of the succeeding chapters.





II.   BACKGROUND DATA COLLECTION



      The purpose of this step in the site investigation process



 is to gather  the data necessary to prepare a work plan, safety



 plan and sampling plan (if required) for the facility and possibly



 collect site  data not developed during the PA.  Most of the



 time, if the  PA was performed properly, it should not be necessary



 to collect additional site data.  However, if there are significant



 gaps between  the time the PA is completed and the SI begins then



 it may be necessary to update PA information.  In another instance,



 the background data simply may be lacking in some relevant data



 that should have been collected during the PA.  If additional site



 specific data must be collected, this should not take a lot of



 time, on the  average.



      The more thoroughly this stage of SI is done the more focused



 the field activities will be and the less field time and resources



 it should take.  If key data is missing in the four categories



 identified in the guidance on preliminary assessments especially



 (1) waste charcterization (2) designated operational characteris-



 tics, and (3) migration pathways characterization, the reviewer



 should determine if all possible sources of the information have
                                1-2

-------
                  FIGURE 1

STEP-BY-STEP BREAKDOWN OF A SITE INSPECTION
       Background Data Collection
   Work Plan/Sample Plan/Safety Plan
              Development
   Work Plan/Safety Plan/Safety Plan
           Review Procedures
              Mobilization
       Access/Community Relations
   Comprehensive Visual Inspection

   Sampling Inspection (if required)
Sample Analysis/Analytical Data Review
            Data Evaluation
              Write Report
             Report Review

-------
been considered.  These pieces of information are perhaps the
most important data needed to conduct an effective and efficient
site inspection.  Information on the nature of waste disposed
in each unit is essential to determine if it is even necessary to
pursue evaluating a unit or facility.  If there are no wastes
of concern, then it is not necessary to proceed further.   Waste
data will guide the inspector in what to look for if sampling is
performed.  The design and operational data and physical  geography/
geology of the site is essential to identifying whether there is
a possibility for a release from a unit, how quickly materials
will release and, if so, where to look for the release.
     This information is invaluable in focusing SI field  efforts,
especially sampling if it is necessary.  For example, certain
types of compounds tend to preferentially migrate via surface
water sediments or ground water; i.e., heavy metals and higher
molecular weight organics.  Where this occurs, it would be
unfruitful to look for releases of such constituents in the
aqueous phase of surface water.  Other materials tend to  bind
extremely well to certain soil types and are essentially  contained
in the site.  Others do not bind well in certain soils or photo-
degrade.  These materials are not likely to be observed away from
the surface.
     At this stage, if gaps in data remain or the data collected
is not sufficiently detailed to be of use, then the owner/operator
should be directed to provide this information.  For example,
USGS maps may not be sufficiently detailed to understand  where
contaminants may migrate, or information previously submitted by
the owner/operator may be too general.  The inspector should

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develop a list of data gaps and request, by letter, the owner/operator
to submit the information.  The letter should be as specific as
possible, identifying the type of information requested, the
source (or possible sources) of the information, and the due date
for the response.
     After all sources have been exhausted, it is possible that
gaps in data may persist especially data on old abandoned SWMUs
that have changed ownership a number of. times.  Where these data
are absent or inadequate then the SI field work will tend to be
larger and broader in scope, generally involve more sampling, and
require the more comprehensive full priority pollutant analyses.
Data gaps may also 'lead the inspector to decide that all further
investigations should be conducted by the owner/operator as part
of an RI—the purpose of which is to obtain the data to decide
if a release of concern is likely.
     After all available information describing facility-specific
units, features, and waste types is collected, the reviewer will
need to consider technical/non-site specific data that will de-
tail the chemical, physical properties of waste and the physical
environment.  This information is necessary to determine:
     (1) what the characteristics of the waste type indicate
         about the route via which the waste will preferentially
         migrate (i.e. via air, surface water, soils, ground
         water, subsurface gas or some combination of these)

     (2) what the characteristics of the surrounding environment
         —soils, geology, hydrogeology, weather, indicate about
         the rate of contaminant migration (i.-e. will soil typee,
         geology, hydrogeology, or weather contain, slow, or
         facilitate the migration of contaminants),

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     There are two prime sources of information describing waste
and physical environment characteristics—reference materials and
periodicals.  At the end of this chapter are some useful reference
materials.
     Appendix A is a list of the more volatile and hazardous
     constituent associated with certain industry's wastes.
     This will assist the reviewer in identifying which volatiles
     to look for with the portable field instruments (Hnu, OVA,
     detector tubes) and what gases to use in calibrating the
     instruments.
     Appendix B^ List B is a list of ground water monitoring
     parameters for a handful of industry types.  This list
     will identify the contaminant characteristics of certain
     industries which one Is likely to detect and, therefore,
     analyze for in ground water.
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       Appendix ^. is a list of commonly identified pollutants  and
       where one might expect to find the contaminants if they have
       been released into the surface water route.
                                                                 r
       Also attached as Appendix J-L-is a list of other standard    " ,->
  reference manuals too large to be included in this  guidance  that
  are also useful in characterizing the waste and physical environ-
  ment and a cryptic identification of the type of information the
  reference material provides.
       Most of this information will be used in the development of
  the sampling and safety plans as well as data interpretation.
  For the sample plan development, the reference material will aid
  in locating optimum sampling locations and determining which
  constituents to analyze for.   For the safety plan development,
  the reference material coupled with prior experience with the
  facility, will aid in identifying the type of protective clothing
  needed and the appropriate respiratory protection.

III.   PREPARATION OF WORK PLANS,  SAFETY PLANS, AND SAMPLING PLANS
       After all the necessary data has been collected, work plans
  and safety plans must be prepared.  If sampling is  required, a
  sampling plan must be developed.  The plans document the proce-
  dures to be used, the resources  needed and the rationale for the
  activities to be undertaken.   These documents insure that all the
  necessary planning, preparation  and review has been done before
  field work begins.  They provide a basis for later  interpreting
  the results of the site inspection and documentation of the
  procedures and technical approach used in the event of future
  enforcement action.

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A.   Work Plan
     The work plan is the umbrella plan that pulls all three plans
together.  The work plan provides for the efficient scheduling of
resources such as manpower, equipment and laboratory services. •
The work plan should include the following:

     o  Introduction.  This section should briefly describe (a.
        few paragraphs) the facility and the objectives of the
        SI—i.e.  conduct visual inspection, collect samples,  etc.
        This section is for the benifit of the person reviewing
        the plan and to document the rationale in the event of
        future enforcement action.

     o  Investigation procedures.  This includes identifying the
        specific standard operating procedures (SOPs) and field
        quality control (QC) procedures to be used.  Appendix  3>
        contains an example check-off list of SOPs and QA proce-
        dures to be used in during the field work.  Use of a
        check-off list prevents weighting down the work plan with
      "•"- reams of boilerplate SOPs.  If the owner/operator is
        collecting the samples, a copy of the SOPs and QA procedures
        should be provided.
     o  Personnel requirements.  This identifies all persons needed
        to conduct the field activities including support person-
        nel and their specific responsibilities.
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     o  Equipment requirement.  All safety and sampling equipment
        and supplies should be identified plus any other support
        or non-standard equipment and supplies.  Attached in
        Appendix £. is an example equipment list.

     o  Contractual services.  Any contractual services needed to
        accomplish the field work.

     o  Waste disposal procedures.  All waste generated as part
        of the site investigation activities, such as disposable
        suits, gloves, sampling materials, must be disposed of in
        an appropriate manner in accordance with RCRA regulations.
        (In most cases it should be possible to get the owner/
        operator to agree to dispose of the waste material at his
        facility.)

     o  Special training requirements.  If any new equipment or
        procedures are to be use then mini training should be
        arranged.

     Special consideration must be given to aspects of the work
which may vary greatly from site to site.   Each one of the follow-
ing areas can'greatly affect the time, expense, manpower and
equipment needed for the project.

    ' o  hazards - What physical or chemical hazards may be en-
        countered?  Are there open manholes, deep embankments, low
        power lines, methane gas vapors, deteriorating surface
        features, poison ivy, snakes?  Is  the facility especially
        large?
                               1-9

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     o  facility location - How far is the facility from the home



        office?  Will samples need to be shipped by overnight



        courrier to the laboratory?  How far away is the nearest



        overnight shipping office?  How accessible is the facility,



        especially inactive areas?





     o  timing - Can the facility be visually inspected or will



        snow obscure facility features? Will the surface waters



        or ground be frozen such as to limit sampling?  Will work



        performed in the winter be limited by short daylight



        hours?  Will work performed in the summer wear out field



        personnel quickly?  How will the season of the year



        affect water levels?  Will leachate springs be visible



        during the dry season?





B.   Sample Plan



     Not all sites will be sampled during the SI state therefore



in some situations in will not be necessary to prepare a sampling



plan.  If sampling is required, the following is a discussion



of the plan's contents.



     1.  Contents of Sample Plan



    It will always be the responsibility of EPA to prepare the



sampling plan and the investigation procedures portion of the



workplan, regardless of whether EPA or the owner/operator actually



performs the sample collection.  This will minimize or eliminate



the risk of bias that could be introduced by the owner/operator



during the sample collection and analyses.
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     The sample plan is encorporated into the work plan and



identifies the sampling locations, rationale and logistics.  The



following outlines the contents of a sampling plan with a brief



discussion of each component.





     o  Field operation.



     The sampling plan should discuss the sequence for conducting



the field activities.  The specific functions of each individual



should be identified in the work plan.   For example,  specific



individuals need to be identified to take samples, maintain the



field log book, monitor the site with instruments, collect samples.





     o  Sampling locations/rationale.



      As precisely as possible, the location of each  sample



should be identified.  A site map should be prepared  to guide



the inspectors to the appropriate location.  Each sample type



should be identified—soil, sediments,  surface water, VOA, air,



ground water and whether the sample is  collected for  metal,



organics, BOD analysis, etc.  The volume of sample to be collected



and the number of samples collected should be identified.  A



justification for the selection of each sampling location should



be provided.





     o  Analytical requirements.



     The sampling plan should discuss the specific parameters



for which each sample is to be analyzed.





     o  Sample Handling.



     The preservation techniques and material for each sample



should be identified.  If sample filtering is needed, that should





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be identified in this section including an explanation of its



use.  The containers used for each sample collection episode



should be described including the tools, supplies, and equipment



needed to collect the samples.  Any procedure not covered by



SOP's or different from the SOP's should be delineated here.





     o  Quality Assurance Samples.



     The number and type of quality assurance samples should be



identified in the plan—specifically the number of blanks, dupli-



cates, or spikes.  The "rules of thumb" for QA samples are dis-



cussed later in this section.





     o  Sample Decontamination.



     The reageants and any special procedures associated with



sample bottle decontamination should be identified in the sampling



plan.





     o  Sampling reports/documentation.



     The sampling plan should describe all sampling forms that



should be filled out Including chain-of-custody forms, sample



receipt forms, sample traffic reports, sample tags.  If any split



samples are to be collected then instructions as to who should



receive the splits should be identified here.





2.   Quality Assurance/Quality Control Program for Sampling



     All samples should be collected in accordance with the



appropriate quality assurance (QA) and quality control (QC).  QA



is the total program for assuring the reliability of monitoring



and measurement data.  SOP's are the cornerstone to a QA program.



SOP's are the exact, detailed procedures for performing a specific





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task such as purging a shallow well, collecting a surface water
sample, etc.  The SOP's insure that the methods, techniques,
and procedures for collecting technical data are correct and
reproducable.  SOP's are developed by persons with considerable.
experience in the particular activity and represent the best way
to collect the sample for a specific situation.  They also insure
that a person collecting the same type of sample somewhere else
or later on is performing it in the same way.  This becomes
particularly important in interpreting the results of the sample
collection and in the defense of data in court later.
     The field sampling activities should be supported by preparing
and submitting several sets of quality control samples.  These
include blanks, spikes, duplicates, and splits.

     o  Blanks
     There are two kinds of blanks of concern for this type of
work:   trip blanks and field blanks.  Trip blanks are used to
determine if inadvertent contamination is introduced from the
sample containers or from an activity other than sample collection
such as---sample shipment, storage.  Blanks are prepared by the
sampler using distilled d-eionized water of known high purity.
These bottles are then sent with the othe sample bottles to the
field but are not opened.  One set of trip blanks for each
analytical parameter group (e.g., organics, metals, volatiles)
should be prepared and submitted for each day of sampling at a
particular site.
     Field blanks are used to determine if contamination is
introduced by the sample collection activities or sampling

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environment.  They are prepared by bringing a quantity of dis-
tilled deionized water to the field and "preparing" a sample by
pouring the water into the bottles.  They can also be prepared by
pouring the sample through sample collection devices such as
bailers.  A field blank should be generated for each day of
sampling at a particular site.
     Blanks should be submitted in the same manner as the other
field samples, with no distinguishing labeling or markings.

     o  Spikes
     Spikes are samples to which a known amount of a compound has
been added and are used to determine if contamination or error is
introduced into samples as a result of laboratory procedures.
One spiked sample is recommended for every ten field samples.
Spiked samples are prepared by the laboratory performing the
analyses after the samples are received at the laboratory.
Although spikes are generally not handled by field personnel,
they are part of the QA process and should be specified in the
sampling plan.

     o  Duplicates
     Duplicate samples are another method of checking on the
precision of a laboratory's analytical methods.  One duplicate
sample should be taken for every ten samples collected at a
facility.  Duplicates are prepared by collecting one portion of
sample, homogenizing it and dividing the sample into equal
portions.

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     o  Splits
     Splits are identical portions of samples split between EPA
and the ownr/operator.  Splits are required only if the owner/operator
is responsible for collecting and analyzing the samples.  Split.
samples are used to evaluate the accuracy of analyses performed
by a laboratory.  Splits are prepared in the field exactly like a
duplicate, but unlike duplicates, splits are always analyzed by
different laboratories.  The owner/operator should be instructed
to prepare a split of all samples.  The EPA inspector will then
select two samples for EPA to analyze from among all the samples.

C.   Safety Plan
     A safety plan should be prepared for each field visits.  All
safety plans should be prepared in accordance with appropriate
EPA guidance.  (See EPA's Standard Operating Guides (SOSG's) for
specific guidance on selecting the appropriate level of protection
and how to prepare a safety plan.)  The safety plan is usually
prepared last and is tailored to the SI activities.  For some
Sis, the safety plan will be very simple and require few protective
measurs-s.  Other, more problemsome sites, may require use of
higher levels of protection.  For example, if the SI involves
sampling lagoons then the safety requirements will probably be
more involved than an SI that involves simple visual reconnaissance.
     Attached at the end of this section is Chapter 9 from EPA's
SOSG's.  The SOSG's were prepared in accordance with EPA and
other Federal health and safety guideline, regulations and orders
This attachment discusses the steps involved in developing a
safety plan and elaborates on the contents of each section of
                               1-15

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 the plan.   Provided below is a brief outline of the contents of



 the plan.   Refer to the Exhibit at the end of this section for



 more detail.



      o  Describe Known Hazards and Risks



      o  List  Key Personnel and Alternates



      o  Identify Levels of Protection to be Worn



      o  Identify Work Areas



      o  Identify Access Control Procedures



      o  Describe Decontamination Procedures



      o  Describe Site Monitoring Program



      o  Identify Special Training Required



      o  Describe Weather-Related Precautions





IV.    WORK  PLAN/SAMPLING PLAN/SAFETY PLAN REVIEW PROCEDURES



      Once  the work plan, sampling plan and safety plans have been



 prepared,  the plans should be reviewed by





      o  other members of the team,



      o  designated specialists/informal peer review,  and



      o  appropriate decision officials.





      The purpose of this .internal review is to ensure that the



 plans are  complete, that the plans meet the goals of  the site



 inspection and that all the appropriate quality assurance require-



 ments for  the field work are met.  Most importantly,  the internal



 review will assist in eliminating any unnecessary sampling and



 ensuring the  proper focus for the SI.



      The other members of the team review the plans to first



 understand their roles in the field activities and second to make
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sure all the appropriate safety and field equipment they will



need to perform their activity is accounted for.



     The plans should also be circulated to individuals within



the office with specialties in the various disciplines associated



with the field work—geologists, geohydrologist, chemists, botan-



ists, engineers, occupational health specialist (safety officer).



These individuals will provide insights into areas with which the



person preparing the plan may not be well aquainted.  They would



comment on the technical approach described in the plans to



insure that sound technical judgment is applied and double check



for any possible inadvertent mistakes or omissions.



     Lastly, the plans should be reviewed and approved (signed)



by an appropriate decision official—at least a first line super-



visor.  This person would be responsible for insuring that the



plan meets all Agency and internal requirements as well as meets



the goals of the investigation.





V.   MOBILIZATION



     In this stage of the SI all the necessary equipment and



supplies are collected, all the equipment checked to insure



they are functioning properly, all the appropriate pieces



available, and any arrangements for sample analysis are made.



If any additional supplies need to be procured they should be



done at this stage.  Also, if any unique contractual or equipment



rental is required this should be done in this stage.
                               1-17

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      Equipment check-out and callibration is a very important



 task in this stage.  Out in the field is not the time to discover



 that the battery is dead, the OVA carrier gas is empty, or the



 Hnu lamp is broken.  Each instrument should be checked following



 the SOP for that particular instrument.   The day of or before the



 instrument is to be used, the instrument should be callibrated.



 At the completion of the checkout and callibration (1) the date



 of callibration, (2) person checking.out or callibrating the



 instrument, (3) the callibration standards used, and (4) a nota-



 tion of deviation from SOP check out or  callibration procedures



 should all be noted in the field or instrument checkout logbook.



      If the work plan specifies sampling, then it is necessary at



 this stage to confirm the availablity of analytical space in the



 laboratory, especially if samples will be analyzed by the EPA



 Contract Lab Program (CLP).





VI.   ACCESS/COMMUNITY RELATIONS





 A.   Owner/Operator Access



      Prior to conducting the field work, the inspector must



 contact the owner/operator to schedule a time for the SI team



 to enter the site and perform the necessary field activities.



 Although it is possible that there has been considerable contact



 with the owner/operator about impending  field work, the appro-



 priate regional person should contact the owner/operator to



 verify dates and the nature of the field activities—sample



 collection, picture taking, facility inspection, instrument moni-



 toring.
                                1-18

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     If the owner/operator is responsible for collecting and
analyzing the samples, then the EPA official should contact the
owner/operator to schedule a date to oversee the field activi-
ties.  The sampling plan and procedures for performing the sample
collection should be sent to the owner/operator sufficiently
ahead of time for him to obtain the appropriate support.  If EPA
is collecting and analyzing the samples, EPA must offer the
owner/operator a split of all samples collected.  If the owner/
operator wishes to have splits, he should be instructed to pro-
vide analytical sample bottles for the splits.
     All arrangements should be followed with a letter confirm-
ing the dates and field activities.  If access is denied, specific
guidance on what to do is provided at the end of this section in
Appendix £• _.                                                 L"TV
     In some cases it may be necessary to access adjacent or
nearby properties in order to conduct a visual inspection or
collect samples.  This may include industries and residents.
They too should receive verbal as well as written notification
of the dates and nature of the work.
     Although the RCRA inspector is authorized to inspect a
facility and collect samples and photographs, the owner/operator
can require that the inspection and sample collection activities
be conducted to protect his or her rights.  The admissibility of
data in court, should the owner/operator file suit against EPA,
may later be challenged if the data was collected in violation of
the owner/operator rights.  For this reason, the inspector
should not appear or act in a coersive or threating manner.  The
owner/operator is free to observe inspection activities, unless

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the owner/operator is interfering with the safe or technically
sound conduct of the site inspection.

     The owner/operator has the right to request confidential
treatment of certain data.  The inspector should avoid agreeing"
to this to the greatest extent possible since it poses a problem
with later using the information in public proceedings under RCRA
or even under CERCLA.  It also poses a sizable burder on EPA to
control the data.  If data deemed confidential by the owner/operator
is needed to properly evaluate the facility then a precise description
of the confidential data should be identified in the field log
book.  The inspector should instruct the owner/operator to follow
up with a letter identifying the confidential data and and explaning
the reason why the data is business confidential.  EPA regulations
governing treatment and handling of confidential data are delin-
eated in 40 CFR Part 2, Subpart B, Sections 2.201-2.309.
B.   Community Relations
     If it will be necessary to conduct any field activities in
or near residential or non-industrial business areas, then appro-
prlate"local officials should be contacted ahead of time.  It is
difficult to remain unobtrusive while conducting site inspections
particularly if field workers are wearing protective clothing.
Moreover, the presence of "official" people collecting samples
can cause undue alarm.  In some cases, it will be difficult to
prevent this but prior, well handled community contact can mini-
mize the alarm.  Each of the regions has a community relation
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  staff to deal with the public for hazardous waste site investiga-
  tions.  These individuals can assist in identifying appropriate
  local community contact for a particular area.

       The Office of Solid Waste is preparing guidance on community
  relations that will be available later this year.  This document
  will provide specific guidance on when and how to implement a
  community relations program at RCRA facilities.

VII.   COMPREHENSIVE VISUAL INSPECTION
       The scope of the field work can vary depending upon whether
  sample collection will be needed.  The field inspection may involve
  at a minimum conducting a thorough visual inspection at the
  facility to confirm information previously collected and to gather
  more information about a facility where data is  lacking.  If
  sample collection will be required, the SI will  often be broken
  into two stages—the first stage wil be to conduct a comprehensive
  visual inspection to gather data about units and releases and to
  identify prime sampling locations.  The second stage will involve
  collecting samples.  If the owner/operator is collecting samples,
  an EPA'person should be present to observe the activities to
  ensure conformance to the work plan, record field activities
  in the log book, resolve any field related problems that develop,
  and ensure proper field quality control.   In some cases, it may
  be possible to eliminate EPA oversight in this phase of the SI
  if EPA personnel are confident of the integrity  of the owner/
  operator and quality of his work.
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     There are a host of different aspects associated with con-



ducting a field inspection.  This section will discuss the key



aspects of a site inspection that involves both a visual inspec-



tion plus sample collection, the sequence of field activities,



photography, logbook maintenance, and chain-of-custody.






A.   Sequence of Field Activities



     Almost all site investigations will follow the same sequence of



events.   Frequently, the only element that varies is the time



required to perform the event.  The following is a list  of tasks



in sequential order.





     (1)  Site Arrival






     During this step, the team arrives at the site, notifies the



owner/operator of arrival and sets up the command post and decon-




tamination line/access control points.





     (2)  Observation/Field Activity



     During this stage of the field work the inspectors  are:



         o  making visual observations,



         o  maintaining a field logbook of observations,



         o  taking photographs, and



         o  monitoring for vapor emissions.





     (3)  Decontamination/Demobilization



     At this stage all persons and equipment exiting the site are



decontaminated.  This occurs not only at the completion  of all



field work but each time persons exit the site, including rest



breaks.
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     In many cases, decontamination may be very simple—simply



removing disposable coverals and washing field boots.  In other



cases, expecially if sampling is performed, then a more involved



decontamination will be needed.   For example, it will probably"



require decontaminating field persons, sample bottles, and sampling



and field equipment.



     All clothing and support materials that will not be reused




must be containerized either for transport and eventual disposal



or to leave on the site.



     (4)  Site Exit



     At this stage the team leader should check out with the



owner/operator.  If requested, the team leader should provide



the owner/operator with -a receipt describing the photographs



taken.





B.   Photography



     Photographs collected during the SI should be taken with



regular 35mm cameras.  Use of unusual filters should be avoided



as they tend to discolor the picture and may unfairly bias the



result by making leachate seeps or lagoon look worse than real



life.  The exact type of camera (including i.d. number), film



(i.e., Fuji, asa 200), and any unusual lenses used must be identi-



fied in the field logbook.



     If during the performance of the site inspection, the owner/



operator withdraws his consent for EPA to be on his facility then



any data collected up to that point is admissible data.  The
                               1-22

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inspectors may chose after leaving the site to collect visual
information from outsite facility property.  If this occurs, then
the data collected must be in plain view from the facility boundary.
Special lenses such as telephoto lens, and binoculars are not
acceptable to use from off-site; regular 35mm cameras are acceptable
     Photographs should be taken to document the conditions of
the facility and procedures used in-inspection activities.  Two
sets of photographs should be taken in the event one camera does
not function or film processing is poor.
     The following identifies the type of pictures that should be
taken:

     o  representative overall picture(s) of facility,

     o  posted signs identifying ownership of facility,

     o  evidence of releases—leachate seeps, pools, discolored
        water, or strained soils,

     o  individual units—lagoons, drums, landfill, etc.,

     o-_. visual evidence of poor facility maintenance.
     o  adjacent land use, and

     o  area of easy access by unauthorized persons.
C.    Logbook Maintenance
     The logbook is perhaps the most important document generated
during the site inpection.  It will serve as the basis for pre-

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paring the final SI report, interpreting data, describing the



site, and most importantly, defending the work done and results



obtained in any future legal proceedings under RCRA or CERCLA.



     A unique logbook should be assigned for each site and each



visit to the site.  Logbook should be bound and each page sequen-



tially number.  Entries into the logbook should be chronological



—a time notation should introduce each entry.  Mistakes in the



logbook should be lined out and initialed.  The logbooks should



be maintained with indelible ink.





     The following is a list of the types of entries that should



be made in the logbook:







     o  All personnel on site during each phase of the on site



        work;





     o  All instruments used during the field work with unique



        identification numbers;





     o  Description of film used;





     o  Description of the weather and changes in the weather;





     o  Result of field measurements—distances, instrument



        readings, well measurements;





     o  Factual description of structures and features—wells



        and well construction, units, containment structures,



        buildings, roads, topographic and geomorphic features;
                               1-24

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     o  Signs of contamination—oily discharges, discolored sur-
        faces, dead or stressed vegetation;

     o  Sketches of facility layout, structured features and
        points of contamination,;

     o  Map of facility showing point and direction of photo-
        graphs; and

     o  Any other relevant items.

For photographic documentation, the following information should
be noted in the logbook.

     o  The sequence of picture number

     o  If more than one camera is used, identification of camera
        (print or slide)

     o  person taking picture

     o  description of picture

     Each page of the logbook should be signed by the person
keeping the logbook and counter-signed by a person accompanying
the logbook keeper.
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VIII.   SAMPLING INSPECTION



        If sample collection is required, it is sometimes possible



   to combine the sampling effort with the comprehensive visual



   inspection.  This would most likely occur where the inspector(s)



   has recently visited the site, is thoroughly acquainted with the



   facility and is able to identify in advance where samples are to



   be taken.  If it is not possible to combine the comprehensive



   visual inspection with sample collection, the visual inspection



   should be geared towards gathering data 'to develop the sampling



   plan.



        The following is a discussion of activities associated with



   a field visit to collect samples.






   A.   Sequence of Field Activities



        In most instances, the sequence of field activities is the



   same regardless of whether the purpose is to collect samples.or



   conduct comprehensive visual observations.



        (1)  Site Arrival



        This step is the same as previously discussed except that



   the inspector should hold a briefing with the EPA field team or



   owner/operator team to review the days events and ensure that



   each team member understands their responsibilities.





        (2)  Preliminary Site Entry



        The preliminary site entry is the first step of the field



   activity.  The purpose of the initial site entry is to screen the



   facility for situations posing a threat to health, and to support



   logistical needs of the site investigations.  Preliminary site entry
                                  1-25'

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will ensure that there have been no changes on site since the



last visit.  When a formal site entry is necessary, at least two



team members should walk through the areas of the facility where



work is anticipated with portable instruments to determine if



there are any vapor releases or radiation emissions, if there



is adequate oxygen, or if there are any explosive atmospheres.



the site since the last visit.  Depending upon the climate from



one day to the next, the concentration of volatiles, explosive



gases and oxygen can change.  Secondly, it is extremely difficult



for field personnel to screen the site while collecting samples,



taking pictures, and maintaining a field log book.



     At the end of this step the team leader should evaluate



whether any information -collected during the initial site entry



changes any of the plans.  For example, it may be possible to



downgrade the level of protection.



     In some cases, it may not be necessary to conduct an initial



site entry if the inspector has had recent contact with the



facility and is confident that the site conditions have not



changed.  The site inspector may have adequate, first-hand



information on the facility to insure that the facility poses no



threat to the health of the inspector.  Where the inspector has



little data on the facility, or is unsure of the reliability or



completeness of existing data, then an initial site entry to .



screen the site is appropriate.



     This step becomes especially important for sampling inspec-



tions.  It is extremely difficult to monitor a site with portable



instruments while collecting samples, taking pictures and



maintaining a field log book.   If a quick screen is performed






                               1-26

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prior to sampling, then the logistics of field work will be



simplified.





     (3)  Sample Activity



     During this stage of the field work, the following tasks are



occurring:



     o  collecting samples,





     o  photographing sample collection,





     o  maintaining the logbook, and





     o  monitoring for vapor emissions.





     Regardless of who is performing the sample collection,



continuous monitoring for vapor emissions is needed to detect air



releases from sampling activities.  If the owner/operator is



collecting the samples, the EPA field team's prime responsibility



is to document precisely the sequence of sampling activities, the



procedures and instruments used, and a description of the samples



(including location, depth, appearance, etc.).





     The EPA Regional offices have developed SOP's for most SI



sampling tasks under the CERCLA program.  For the most part these



SOP's are applicable to RCRA field activities.  If the SOP's are



not applicable or appropriate for the particular field activity



then a new SOP should be developed.  In some cases, only minor



modifications are necessary.  Were modification to existing SOP's



are made, then the exact modifications must be noted in the field



logbook.
                               1-27

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     (4)  Decontamination/Demobilization
     This stage Is the same for a comprehensive visual SI.  In
addition to personnel and equipment decontamination, all samples
must be decontaminated.  All sample identification forms, sample
shipping forms, chain-of-custody forms, sample receipts, and
sample traffic forms are completed.  Some of the information on
these forms can be filled in prior to the sampling and is in fact
recommended due to the number of forms and time required to
complete these.  Examples of each of these forms are contained in
          .,
Appendix  rr_   All samples are packaged for safe transport.  If
samples are to be shipped by express carriers, then the samples
are packaged in accordance with DOT specifications for shipping
of hazardous materials.

     (5)  Site Exit
     This stage is similar to the procedure discussed previously.
In addition,  the Inspector should deliver a receipt describing
the samples collected.  The inspector should obtain a written
acknowledgement of the receipt of sample form.  If the owner/
operator requested split samples, then the samples would be left
with him at this time.
B.   Photography
     The same principles previously discussed apply to sample
collection tasks.  Photographs should be taken of:

     o   posted signs identifying ownership of facility,

     o   sampling locations, and
                               1-28

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     o  sampling activities.
C.   Logbook Maintenance
     The same principles discussed previously also apply here.
The following is a list of the additional types of entries that
should be made in the logbook for sampling inspections:
     o  description of sample (appearance),

     o  exact depth from which sample taken,

     o  description of location of sample,

     o  map(s) identifying site layout and sampling points

     o  field calculations,

     o  decontamination procedures used between collection of
        each sample,

     o  any deviation from SOPs, and

     o  any other relevant item.

E.   Cnaln-of-Custody
     All samples collected (including blanks and spikes) should
be maintained under chain-of-custody.  The purpose of chain-of-
custody is to insure that data collected during the SI is not
tampered with before it is analyzed.  Chain-of-custody traces the
possession of a sample from the time of collection, through all
transfers of custody, to when it is received in the laboratory,
where internal laboratory chain-of-custody procedures take over.
For samples that are spiked in the laboratory,  chain-of-custody
                               1-29

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 should be maintained from the time the sample is  prepared in the
 laboratory to when it is received in the laboratory for analysis.
      Specific chain-of-custody procedures are included in the SOP
 of chain-of-custody.

IX.   SAMPLE SHIPMENT/ANALYSIS OP SAMPLES

      At this stage of the SI, any samples that were collected by
 the EPA or splits of samples collected by the owner/operator,
 are delivered to the laboratory and the samples analyzed.  If
 the analysis is performed by the EPA Contact Lab  Program (CLP)
 then most samples will have to be shipped by overnight courrier.
 This will involve driving the samples to the closest overnight
 courrier office and completing the appropriate sample shipment  forms.
 Most samples collected at hazardous waste facilities are regulated
 by the Dept. of Transportation requlations governing shipping of
 hazardous materials.  SOP's covering sample shipping are available
 in each of the regional offices or in EPA safety  training manuals.
 The time involved in analyzing samples can vary from 40 days to
 three .to four months.

 X.   ANALYTICAL DATA REVIEW
      Upon receipt of analytical results, the data must be reviewed
 to insure that the results are valid.  This particular step can
 take a considerable amount of time depending upon the backlog of
 data packages requiring review.  The EPA Regional Environmental
 Services Divisions (ESDs) are responsible for quality assurance
 review of analytical data.  In some cases, some or all of the
                                1-30

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 responsibility for data review is delegated to the group respons-
 ible for collecting the samples.
      Some of the data review responsibilities can be delegated to
 the persons collecting the samples and do not require involved .
 training or experience to perform.  Primarily these involve en-
 suring that all deliverables required by the CLP are included
 in the data package, checking that all forms are completed within
 the requirements of the contract, flagging missing data or incom-
 plete forms, and reporting these to the appropriate person for
 follow-up.   Depending upon the arrangements in the particular
 Region, the preliminary data review can also involve completing a
 checklist of questions which summarize key quality assurance items
 in the data package.
      With the results provided by this preliminary data review,
 missing data will be requested and the ESD's will perform a
 qualitative analysis of the data.  Based on the abundance of
 laboratory internal quality assurance data provided in the data
 packages the ESD determines if the data results are valid.
      At the completion of the analytical data review, all the
 data collected to that point is evaluated to determine if a
 release or potential for release has occurred.  The substance of
 the data evaluation stage is contained in the succeeding chapters.

XI.   FINAL REPORT/FILES
      After evaluating all the data, a brief report summarizing
 the results, findings, and recommendations, should be prepared.
 This report should not on average be more than fifteen pages
 long.  In some cases the report may be longer for a particularly

                                1-31

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complicated site.





     The report should identify the areas or units that are



releasing or suspected to be releasing and the basis for these



findings.  The report should also recommend, area (or units)



where no further action, immediate interim corrective action, or



remedial investigation is required.  The basis for these



recommendations should be clearly substantiated in the report.



The relative priority of the facility for follow up investigation



should be explained.  In addition, where further action is recommended,



the report should also describe the scope of further action.



     The following is a recommended outline for a SI report.  It



may not be necessary to discuss all the items identified in the



outline if the discussion is clearly irrelevant to the particular



site.  For example, it may not be necessary to elaborate on the



geology or hydrology of an area if the only unit of concern is an



inactive above ground storage facility with no problem spill,



discharge or overflow problems.





     9  Site Background



     This section should summarize, among other things, the loca-



tion of the facility, the types of hazardous waste handling



practices (by unit), which units are regulated, the layout of the



facility (include a map), how long the facility and units have



been in operation, and the site ownership.  This section is not



intended to repeat detailed data already provided in the Part B



application or CERCLA SI report.  The report should briefly summarize



data found in other documets, and describe new data identified.
                               1-32

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     o  Environmental Setting
     This section should describe, in summary form, the media
surrounding the facility—the relevant climatic, geological,
hydrogeological, and topographical factors.  Maps, sketches, and
selected photographs would be included in this section to further
describe the physical environment.  Also included in this section
would be a discussion of target populations and environments—
including public and private water supply ground and surface
water intakes, protected areas, parks, wetlands, affected irrigated
crops and livestock.

     o  Unit/Waste Description
     This section would discuss the types of units found at the
facility and their tendency to cause releases into the air,
ground water, surface water, soil and subsurface gas.  This
section would discuss the relevant design and operational features
that exist or do not exist to adequately contain hazardous wastes
or releases of hazardous wastes.  This discussion would also
include situations where it is unknown what type of design or
operational features existed to control or contain hazardous
waste.  As part of this-discussion, the types of wastes handled
by each unit would be described.

     o  Laboratory Results
     This section would discuss the results of previous and new
analytical results.  Much of the information in this section
would be presented in tabular form and would be accompanied with
maps locating sample collection points.
                               1-33

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     o  lexicological Characteristics
     This section would discuss toxicological characteristics of
the wastes releasing or suspected to be releasing into the envi-
ronment.  The report would focus only on the most toxic and
persistent chemicals releasing.

     o  Conclusions and Recommendations
     This section would present the findings and conclusions from
those findings.  Documented releases should be discussed in  .
this section as well as findings that releases are soon or likely
to occur.  Areas where insufficient data document a release
should be discussed.  Units that are found not to be releasing
should be identified and discussed.  Recommendations for further
action on units not eliminated from further consideration should
be presented.  Where the facility or some portion of the facility
is recommended for an RI or corrective action, brief and generalized
discussion of the scope of further work should be included.
Recommendation for deferral of further action should also be
explained in this section.

     o  Bibliography
     This section would Identify all sources of information used
in the evaluation and preparation of the SI report.   This portion
would be essential if the facility is referred to the CERCLA
program for consideration for the National Priorities List (NPL).

     o  Appendices
     Any relevant memorandum, reports, pages from reports, maps,
etc. that elaborate upon or further substantiate information in
                               1-34

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the SI report would be attached In this section.
     A copy of the final report plus all memoranda,  photographs,
logbooks, trip reports, workplans, sampling plans,  safety plans,
sample tags, chain-of-custody forms, records of communication,
plus any new reports or documents uncovered in the  course of
conducting the SI, should be entered into the official facility
file.  All this information will be used as evidentiary documentation
In any future court proceedings.
                               1-35

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                           CHAPTER  FIVE

                         ' SURFACE WATER


I.  INTRODUCTION

     The site investlgation •  for  surface water  should  determine

whether solid waste management units at the  facility  have  released

and/or will continue  to release  hazardous  wastes  or  hazardous

constituents to surface water.1  For units with  identified releases,

or for which there  is a substantial likelihood of  a  release,  the

owner or operator will be required  to conduct  further investigations

to actually determine the extent of a release(s)  and/or  to charac-

terize the release and begin developing a  corrective  measures

p rogram.

     Although EPA is  primarily concerned with  releases  to  surface

water, such releases  can also  migrate overlaod and potentially

expose human and environmental receptors.  Releases  to  surface

water and off-site may result  from  point source  discharges,

spills, leaks,  surface  run-off,  or  floods.

     The investigator will need  to  make determinations  regarding

the need for further  lovestigation  at a unit on  a  case-by-case

basis, considering factors that  are unique to  each unit.   For

some units, it may be relatively easy to assess  the  potential for

surface water contamination  and  to  determine the  need to  conduct

further investigations.   For other  units,  it may  be  more  difficult

to make these determinations and the investigator  will  need  to

use judgment in deciding whether farther investigations  are

warran ted.
     1   Surface water  includes  any  stream,  river,  lake,  bay,
wetland, estuary, and  intermittent  stream.

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     Releases that result  la  surface water  or  off-site  contamina-




tion can be difficult  to identify because of  their  intermittent




nature.  For example,  a  surface  impoundment may  regularly  overflow




and release hazardous  constituents  during periods of  heavy  rain-




fall.  However,  unless  the  site  investigation  is  conducted  during




a heavy rainfall, the  investigator  will  not observe  the release.




Therefore, he/she should evaluate each  unit at the  facility for




its potential to cause  surface water releases  and examine  the




site for evidence that  indicates such  releases have  occurred or




occur on a regular basis.   The investigator will  also  need  to



assess whether such  releases  threaten  human health  and  the  envi-




ronment before determining  that  further  investigations  are




necessary.




     The comprehensive  investigations  called  for  in  the second




phase of the corrective  action process  require a  considerable




investaent of time and  resources for both  the  owner  or  operator




in conducting the investigation, and for the  agency  in  reviewing




technical plans and  analytical results.   Therefore,  the PA/SI




should serve the dual  function of identifying  situations which



me r 11-_ f ur ther investigations  for surface water releases, and at




the same time avoiding  unnecessary  investigations.




     This chapter describes  tha  factors  the  investigator should




consider in assessing  specific units and the  site for  their




potential to cause releases  to surface  water.   It also  describes




the kinds of evidence  the  investigator  should  look  for  to  identify




whether or not a release has  taken  place and  fictors  to consider




in assessing the potential  for releases  to  threaten  human  health




and the environment.






                               5-2

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II.  POTENTIAL FOR SURFACE WATER  RELEASES  FROM  THE FACILITY

     Four factors are  important  in  assessing  the potential  for

surface water contamination  from  a  facility.   They are:

     o  the proximity  of 'the  facility  to surface water;

     o  the potential  for releases  to  migrate from the
        facility to surface  water or directly to off-site
        receptors;

     o  the design and physical  condition  of  solid waste manage-
        ment units at  the facility; and

     o  the type of wastes contained  in  these units.

The importance of each of these  factors  is  discussed  below.

Proximity to Surface Water and Release Migration Potential

     The potential for surface water contamination from  a  facility

is directly related to the facility's  proximity to surface  water.

Facilities located along rivers  or  other surface water bodies are

more likely to have surface  water releases  than facilities  located

in arid areas, far from significant surface water bodies.   As the

distance to surface water increases,  it  becomes more  likely  that

hazardous constituents in surface run-off  will  sorb to soils  or

move downward in the unsaturated  zone  and  result in ground  water

con tami na tion.

     The potential for surface run-off from the facility to

migrate overland to nearby receptors  is  only  of concern  when  the

facility is located adjacent  to  populated  areas and no barrier

(e.g., runoff control  system) exists  to  prevent further  overland

migration.

     Proximity is not  the only factor  that  affects the potential

for releases to migrate to surface  water or drain off-site.   The

facility slope indicates the  potential for  run-off or spills  to
                                5-3

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migrate from the facility.  For  example,  releases  from  a  facility




located in a depressed area are  unlikely  to  leave  the  site as




surface run-off.  The composition  of  the  soil  and  the  slope and




vegetation of the terrain between  the  facility  and  the  nearest




surface water body will also  affect  the migration  potential of.




the release.  For example, a  facility  located  close  to  surface




water may have a low potential  for surface water releases if the




intervening terrain is characterized  by sandy  soils  and heavy




vegetation.  In  this case, run-off is  more likely  to migrate down




into the unsaturated and saturated zones  rather than to migrate




laterally overland to surface water.   However,  fac 11ities located




in areas characterized by clayey soil, and where there  is less




extensive vegetation between  the site  and nearby surface  water,




have a greater potential for  releases  to  surface water.




     The level of rainfall and  the frequency of significant storm




events also affect the potential for  run-off from  the  facility to




contaminate surface water.  As  mentioned  earlier in  this  chapter,




surface water releases are often intermittent  and  result  from  run-




off generated during periods  of  heavy  rainfall.  A  facility lo-




cated in an area characterized  by  frequent major storm  events  is




more likely to generate large volumes  of  surface run-off  than  a




facility located in an area where  major storm  events are  less




f req uent.




     The assimilative capacity  of  the  closest  surface  water body




also affects the migration potential  of releases from  a facility.




Large streams with high flow  rates will  tend to degrade or mix




and dilute constituents mora  rapidly  than smaller  streams with




lower flow rates.
                                5-4

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     The investigator will need  to consider all  of  these  factors

— proximity to surface water, soil composition,  slope and

vegetation characteristics of  the facility and  the  intervening

terrain, assimilative capacity of nearby streams, rainfall,  and

the frequency of major storm events --  to determine  how  the

facility's location affects the  potential for releases to surface

water or the movement of surface run-off to off-site  receptors.

Untt Design and Physical Condition

     As with the other media,  the potential for  surface  water  contam-

ination from a solid waste management unit is largely dependent

on the nature and function of  the unit.  For example, open units

that contain liquids (e.g., surface impoundments) have a  greater

potential for surface water releases  than closed  landfill cells

that have been properly capped.

     Table 5-1 ranks types of  solid waste management  units,  in

a loose descending order on the  basis of their  potential  for

having releases that cause surface water contamination or migrate

off-site as surface run-off.   The table is intended  to provide

a general sense of the relative  potential for units  to cause

thesei.types of releases.  The  investigator will  also  need to

evaluate unit-specific factors in determining the potential  for

surface water releases from a  particular unit.

     The major unit-specific factors  the investigator should

evaluate include:

     o  uni t design.   The investigator  should determine  whether
        the unit has  engineered  features (e.g.,  run-off  control
        systems) that are designed to prevent releases to surface
        water.   If such features are  in place,  the  investigator
        should evaluate whether  they  are adequate (in terms  of
        capacity,  engineering, etc.)  to prevent  releases.
                               5-5

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                 Table 5-
Unit Type

Landfill
Surface Impoundment
Waste Pile
Container Storage Area
1.     UNIT POTENTIAL FOR SURFACE WATER
     RELEASES AND MECHANISMS OF RELEASE

  Release Mechanism

  o Migration of run-off outside the unit's
    run-off collection and containment system

  o Migration of spills and other releases
    outside the containment area from loading
    and unloading operations

  o Releases from overtopping

  o Seepage through dikes to surrounding
    areas (i.e., soils, pavement, etc.)

  o Migration of run-off outside the unit's
    run-off collection and containment system

  o Migration of spills and other releases
    outside the containment area from loading
    and unloading operations

  o Migration of run-off outside the con-
    tainment area
Land Treatment Unit
Above-ground Tank
In-ground Tank
Inc inera tor
Class I and V
Injection Well
  o Migration of run-off outside the con-
    tainment area

  o Releases from overflow

  o Leaks through tank shell

  o Spills from coupling/uncoupling opera-
    tions

  o Releases from overflow

  o Spills from coupling/uncoupi ing opera-
    tions

  o Spills or other releases from waste
    handling/preparation activities

  o Spills due to mechanical failure

  o Spills from waste handling operations
    at the well head
*  The two remaining solid waste management  units; waste  transfer
   stations, and waste recycling operations  generally  have  mechanisms
   of release similar to tanks.
                                  5-6

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making these determinations.  To  the  extent  waste  information  is

available, the investigator may be able  to  take  these  factors

into account.  Each factor  is discussed  more fully  below.

     1.  Mas s.  The mass of a contaminant relative  to  the  volume

of the receiving water  body is one of  the primary  factors  governing

the environmental significance of a release.   The  high volumes  of

water present in some rivers and  lakes will  dilute  many contam-

inants so that concentrations are below  levels  that impact human

health or the environment.  Volume and flow  rate govern the

ability of a water body  to  assimilate a  contaminant.   Larger

bodies of water can assimilate higher quantities of pollutants

than smaller ones, and  more turbulent streams  and  rivers expedite

the mixing and dilution process and assimilate  pollutants  more

quickly than slow moving or stagnant  bodies  of  water.

     2.  Transport Mechanisms.  The transport  mechanisms governing

the movement of pollutants  control their ultimate  destination.

The primary transport mechanisms  are  sedimentation,  volatilization,

and downstream transport in the water column.   The  strucutre and

properties of each constituent will govern  which mechanisms

dominate their transport.   While  most constituents  can be  affscte'd

by all three  transport  mechanisms, it  is possible  in most  cases

to partition a constituent  to one primary destination.  This

information can be used to  predict where specific  constituents

will result in potential exposures.   A brief description of each

fate and transport mechanism follows:

     o  sedimentation.   Sed linen ta t ion  refers to  the tendency of a
        constituent to  sorb onto  suspended  organic  sediments
        carried in water bodies.  Sorption  can  be  modeled  using a
        sorption isotherm,  which  predicts  the  relative tendency
        of a constituent to be partitioned  to  suspended particles


                               5-8

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        or to remain dissolved  in  the water.   The  sorption parti-
        tion coefficient, KSW,  describes  the  tendency  of  a con-
        stituent to be dissolved  in  the water phase  or to be
        sorbed onto a particle.   Once a constituent  has  become
        sorbed to a particle  in the  water,  it will usually join
        the bottom sediments  of  the  system.

     o  vola tilization.  Compounds exhibiting a  strong tendency
        to volatilize from water  will pose  little  risk to human
        health or the environment  through  surface  water  exposures.
        Many chlorinated solvents  will almost completely  vola-
        tilize from a moving  stream  within  several miles.  Com-
        pounds with large Henry's  Law constants  will  have the
        greatest potential for  volatilization.   It will  be ac-
        centuated in turbulent  water systems  such  as  fast moving
        streams, where the turbulence speeds  up  the  transfer of
        contaminants from water  to air.

     o  downstream transport.   Relatively  immiscible  organic
        compounds with densities  less than  water (e.g.,  oily
        wastes) will tend to  float on water surfaces  in  slicks,
        where they may pose a significant  threat to  water fowl.
        Other immiscible compounds which  are  heavier  than water
        will tend to sink into  the sediments  where they  will
        remain largely undlssolved in the  water  column.   Dissolved
        constituents will be  transported  downstream  in rivers and
        dispersed in lakes where  they will  be subject  to  natural
        fa te processe s.

     3.  Pers is tence.  Many fate  processes  can combine to degrade

a pollutant to a level below  which there  is no significant risk.

Among  the many fate processes are: hydrolysis, photolysis, oxida-

tion/reduction, biotrans formation, and bioaccumulation.   Many

references will report a value  for a chemical's  half-life in

water""based upon a combination  of  these processes.  In this way,

one can make a general assessment  of a constituent's  persistence

in the environment.  The most persistent  constituents  (e.g., PCBs,

dioxins, etc.) will not be significantly  degraded  by  any  of the

fate processes mentioned above  and should  generally  be considered

to pose a considerable risk.  Bioaccumulation deserves special

mention due to the unusual threat  it poses  to animals  in the food

chain.  Concentrations of constituents that bioaccumulate in fish

and shellfish may be higher in  the fish  than  they  were in the


                                5-9

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original release.  Pollutants  that bioaccumulate  should  be  given

special consideration in water bodies used  for  recreational  or

commercial fishing.

     4.  Toxicity.  The most pertinent  factor  in  assessing  the

significance of a release of hazardous  constituents  to surface

water will often be the intrinsic  toxicity  of  each  individual

contaminant.  Large releases of certain non-carcinogens  may  be

assimilated in streams or lakes without consequence  to human

health or the environment.  However, low  concentrations  of  highly

toxic and/or persistent constituents like dtoxin, PCBs,  arsenic,

and cyanides may pose a significant human health  risk.   Unfor-

tunately, toxicity information for many of  the  Appendix  VIII

constituents is incomplete.  For  this reason,  it  will often  be

advisable to consider highly persistent constituents  to  be  of  the

greatest concern, because exposures can occur  over  a considerable

length of time with unknown consequences.

     While the overall fate and transport of a  constituent  in  a

surface water system will depend  on the specific  characteristics

of the system, it is possible  to  generally  describe  the  likely

fate and transport for certain classes  of contaminants.   If  the

investigator knows the wastes  in  the unit,  this  information  may

help in determining which contaminants  are  of  particular concern

for surface water releases.

     o  metals (e.g., arsenic, chromium,  cyanide, and mercury)
        usually adsorb and accumulate in  sediments  in rivers and
        lakes.  The rate at which  they  concentrate  in the sediments
        will depend on the organic content  of  the suspended
        solids in the system and  on the concentration of clays  in
        the water.  Most metals will exhibit a  tendency  to  bio-
        accumulate in both shellfish and  finfish.   They  will
        therefore pose the greatest threat  to  human  health  in
        waters known to be used for recreational  and  commerical
        fishing.


                               5-10

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     o  chlorinated pesticides  (e.g.,  DDT,  chlordane,  lindane,
        heptachlor, toxaphene,  etc.)  may  be  subject  to several
        fate and  transport  processes  simultaneously.   They have
        been shown to volatilize,  sorb  onto  sediments, biodegrade,
        and bioaccumulate.   In  large  quantities,  chlorinated
        pesticides mmay pose  a  significant  risk  from  exposure
        throughout the water  body.

     o  halogenated alipha tic hydrocarbons  (e.g.,  trichlorethane,
        tetrachlorethene , chloromethane,  etc.)  generally exhibit
        a strong  tendency  to  volatilize from water.   Large quan-
        tities of  these pollutants  can  be stripped  from fast-moving,
        turbulent  streams,  reducing their risk  for  water-associated
        exposures.  Although  they  will  not  tend  to  be  transported
        downstream, they generally  do  not degrade  significantly
        in the environment.   Many  of  these  compounds  may still
        pose a significant  risk at  low  concentrations  due to
      .  their toxicity.

     o  polycyclic aromatic  hydrocarbons  (e.g.,  napthalene,
        phenanthrene, benzo(a)  pyrene,  etc.) will  tend to adsorb
        to bottom  sediments.  These pollutants  are  generally
        susceptible to biodegration and hydrolysis  in  surface
        water systems.  Because they  do not  tend  to  bioaccumulate,
        releases characterized  by  low  concentrations  of these
        pollutants are likely to  be of  little concern.


Summary of Factors Affee ting  the  Potential  for  Release

     The  investigator should  consider  all of the  factors described

above to determine a  unit's  surface water release  potential.   In

addition,  in assessing a unit's potential for surface  water

releases,  the investigator  should  consider  how  the  various factors

affec'-L each other.  For example,  an above ground  tank  containing

relatively toxic,  persistent  waste  and  located  within  1000 feet

of a river may not have a secondary containment  or  other system

in place to collect liquid  waste  that  could  leak  or overflow

from the  tank.  However, the  facility's records  indicate that the

tank is relatively new, well  designed,  and  well  constructed,  and

that it is inspected  regularly  for  evidence  of  leaks.   In this

case, there is only a low potential for a release  to  surface

water, and no further investigation would be necessary.


                                5-11

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Alternatively, the same situation with  an  older  tank  that  shows

signs of deterioration may require further  investigation.


III.  EVIDENCE OF SURFACE WATER RELEASES

     If the investigator determines  that certain  units  at  the

facility have the potential  to cause  releases  to  surface water,

he/she should inspect  the area around  the  units  of  concern and

the area between the unit and the closest  surface water body  for

evidence of a release.  In addition,  if  the  facility  is located

adjacent to surface water, the investigator  should  examine the

surface water for evidence of releases.  The  investigator  should

look for the following types of evidence:

     o  unpermitted discharges to surface  water  that  require
        NPDES or Section 404 permits.   Hazardous  waste  facilities
        may be using certain practices  that  require permits under
        the Clean Water Act.  The investigator should  examine  the
        site for the following types  of  discharges  and  determine
        whether these discharges are  permitted:

        -- discharges  from collection  and  holding facilities
           (e.g., tanks, basins, surface impoundments,  etc.);
        -- discharges  of contaminated  ground  water  from a
           counterpumping activity;
        — discharges  from a leachate  collec tion/trea taien t system;
        -- placement of dredge or fill  material  in  the  water;  and
        — units (including  old fill  material  that  is  now  consi-
           dered hazardous waste) in  surface  water.

     o  visible evidence of  uncontrolled run-off  from  units at
        the facility.  If releases have  occurred  or are occurring
        at a unit there, is likely to  be  evidence  around the unit
        that indicates a release is  taking  place.   Because of  the
        intermittent nature  of most  surface  water  releases, it
        is particularly important to  examine  the  site  and  nearby
        surface water  for physical evidence  of  release. The
        investigator should  look for:

        — observable  contaminated run-off  or  leachate  seeps;
        -- drainage patterns that indicate  possible run-off from
           units at the facility;
        — evidence of wash-outs or  floods,  such  as highly eroded
           soil, damaged trees, etc.;
        -- discolored  soil,  standing  water,  or dead vegetation
           along drainage patterns leading  from  the unit;  and
        — discolored  surface water,  sediment  or  dead  aquatic
           vege ta t ion.

                               5-12

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Use of Sampling  to Support Other  Evidence  Obtained




     Depending on the other evidence  collected,  it  may be  desire-




able to sample run-off, on-site  soils,  standing  water, surface




water,  and/or surface water sediments.   While  the Agency  expects




that in general, it will not be  necessary  to  take samples  duri-ng




the PA/SI, there may be certain  situations  where sampling  can




confirm other evidence that a  release  has  taken  place  at  a unit




or that there is no release from  a  unit.   Sampling  should  only be




conducted to verify or confirm other  evidence  collected.




     For example, inspection of  units  and  the  facility may indi-




cate the potential for surface water  releases  (e.g.,  tanks at the




facility are older and inadequately  designed;  many  have contained




toxic wastes for more than 20  years;  and  the  facility  is  located




adjacent to a relatively small stream).   While there  is ao visible




evidence of leaks or fractures in  the  tanks,  other  evidence




indicates that surface water releases  are  taking place (e.g.,




run-off in drainage channels leading  from  the  units is discolored,




and there is dead vegetation along  the drainage  channels).  In




this case, the investigator may  want  to  sample run-off in  the




chann-els for indications of contamination.




     In general, simple field  tests  or sampling  may be adequate




to obtain a positive confirmation of  surface  water  or  surface




run-off contamination.  More thorough  sampling may  be  necessary




to conflm that  the contamination results  from a particular unit,




but this more detailed sampling  may  be completed as part  of the




next phase of the corrective action  process.   If the  investigator




determines that  sampling is necessary, he/she  should  follow the




procedures that  are provided in  Appendix   .   Procedures  for
                                5-13

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analyzing samples for  hazardous  constituents  described  in 40  CFR

Part 261, Subparts C and  D, can  be  found  in "Test  Methods for

Evaluating Solid Waste, Physical/Chemical  Methods  (SW-846)."


IV.  EXPOSURE POTENTIAL

     If  the investigator  observes  discharges  or  releases  to

surface water or other evidence  that  such  releases  are  taking

place, he/she may choose  to use  exposure  information  (to  the

extent it is available for the facility)  to:   1) determine the

need for further investigations; and/or 2) set priorities for

conducting further investigations.

     The following types  of information are useful  in evaluating

the exposure potential of surface water releases:

     o   information on the use of  the surface  water body  that
        receives the release.  The  investigator  should  determine
         the use of the surface water  body  (e.g., no use,  commer-
        cial or industrial, irrigation, economically  important
        resource (e.g., shellfish,  commercial  food  preparation,
        recreation, or drinking).   A  release  is  more  likely to
        significantly  impact  surface  water that  is  used as a
        drinking water source than  surface water in industrial
        areas that have a commercial  or industrial  use.

     o  information on the location of any drinking or  irrigation
        water intakes  listed  in  public records or  otherwise known
        within a reasonable distance  of the release.

     o  Information on the nature and extent  of  the contact human
        and environmental receptors are likely to  have  with run-
        off from the facility.


V.  SUMMARY AND EXAMPLES

     This chapter has  identified certain  unit-specific  and site-

specific characteristics  that should  be evaluated  to  determine

the potential for surface water  releases  or releases  that migrate

off-site in surface run-off.  These characteristics include:   the

proximity of the facility to  surface  water; factors such  as soil
                               5-14

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type, slope, and vegetation of  the  intervening  terrain  that




affect the migration potential  of a release;  the design and  physi-




cal condition of solid waste management  units at the  facility;




and the type of waste contained  in  the solid  waste management




units.  The Investigator should  examine  each  of  these factors  and




how they relate to each other in determining  the potential for




surface water releases from units at  the  facility.




     Once the investigator determines  that  the  potential  for




surface water releases exists at a  facility,  he/she should examine




areas surrounding the units of  concern and  the  site as a  whole




for evidence that releases have  occurred  or are  occurring at a




facility.  Due to the intermittent  nature of  most surface water




releases, it is important  to look for  physical  evidence such as




drainage patterns, dead vegetation, etc., that  Indicates  that




releases have taken place.  The  investigator  should also  consider




the potential for exposure from  these  releases  before making a




determination that further investigation  is necessary.




     Table 5-2 provides examples of situations  that are likely




to require further investigation and  situations  that  probably




will trot require further investigation.
                               5-15

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                               Table 5-2
                           UNIT ILLUSTRATIONS
 nit Type

Landfills
Vaste Piles
Surface
Impoundmen ts
Container
S torage
Areas
Land Treat-
men t Units
Further Investigation
Needed	

Closed units, inadequate
or deteriorating cover,
no run-off control system;
drainage patterns indicate
contaminant migration  (i.e.,
discolored soil and/or dead
vegetation); near downgrad-
ient surface water/off-site
receptors

Closed units, waste inade-
quately covered, no run-off
control system; drainage
patterns indicate migration
of contaminants; near  sur-
face water

Operating/closed units with
inadequate freeboard or
deteriorating dikes; located
adjacent to stream that has
downstream drinking water
in take s

Operating/closed units with
deteriorating dikes; evidence
of release; near surface
wa te r

Inactive units with leaking
containers; visible evidence
of soil contamination; no
run-off control system,
drainage channels indicate
migration of hazardous
constituents
Inactive/operating units
with visible evidence of
soil contamination; unit
design allows run-off; near
downgradient surface water
and/or off-site receptors
Further Investigation
Not Needed	

Operating units with
adequate run-off
control systems

Closed units with adequate
caps or covers; no evidence
of run-off from the unit
Operating units with run-
off control systems

Closed units with adequate
caps or covers; no evidence
of run-off from the unit

Older operating/closed
units with adequate freeboard
and overtopping controls;
limited potential for off-
site exposure;  more than 3
miles from nearest surface
wa ter
Operating units with new,
well sealed containers; or
adequate run-off controls

Inactive units with well
sealed containers; ade-
quate run-off controls;
limited potential for off-
site exposure, no nearby
downgradient surface water

Inactive/operating units
with adequate run-off
controls; limited potential
for off-site exposure
                                     5-16

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                          Table 5-2 (Continued)
                            UNIT ILLUSTRATIONS
 IP it Type
Tanks
Incin-
era tors
Class I/
IV Inject-
ion Wells
Further Investigation
Needed
Older concrete units with
no secondary containment,
some visible deterioration;
visible evidence suggests
some overland migration of
hazardous constituents;
near surface water

Unit with visible evidence
of soil contamination
from apparent (or recorded)
overflow events or other
operational or structural
failures; unit in area with
clayey soil, near surface
wa ter

Evidence of recurring spills
that result from waste
handling operations;
drainage channels leading
from the unit indicate
contaminant migration;
near surface water

Evidence of recurring spills
that result from waste
handling operations; drainage
channels leading from the
unit indicate contaminant
migration;  near surface water
Further Investigation
Not Needed
Well-designed, construc-
ted units; inspected
regularly; no evidence
of leaks
                                             Older units that shown
                                             signs of deterioration;
                                             no potential for off-
                                             site migration of con-
                                             s tituents
Design ensures containment
of spills that could occur
during waste handling
opera tions
Design ensures containment
of spills that could occur
during waste handling
opera tions
                                      5-17

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                           CHAPTER SIX




                               AIR




I.  INTRODUCTION




     The site Investigation for air should  determine whether  solid




waste management units at the facility have  released or  are




likely to have released hazardous wastes  or  constituents to  the




air.  Owners or operators of units with  identified  releases or




that have a substantial likelihood of a  release  will be  required




to conduct further investigations to actually  determine  the




extent of a release(s) and/or to characterize  the  release  and




begin developing a corrective measures program.




     In general, two  types of air releases  can occur at  solid




waste management units:




     o  releases that are continuous in  nature,  and




     o  releases that are intermittent or catastrophic  In  nature.




This guidance is primarily concerned with evaluating the likelihood




and significance of continuous releases.  It  is  assumed  that  all




units that expose hazardous waste to the  ambient atmosphere have




air releases; the investigator will need  to  use  judgment in




determining whether these releases are significant  enough  to




warrant further investigation.  For some  units it  may be relatively




easy to make these determinations; for other  units,  these  deter-




minations may be more difficult.




     Because the comprehensive investigations  called for in  the




second phase of the corrective action process  require a  considerable




investment of time and resources for both the  owner or  operator




and for the agency, the PA/SI should serve  the dual role of




identifying situations which merit further  investigations  for  air

-------
releases while at the same  time  avoiding  unnecessary  investigations.




     This chapter describes  the  factors  the  investigator  should




consider in evaluating specific  units  and  the  facility  as a whole




for their potential to cause air  releases.   It  then describes  the




kinds of evidence the investigator  should  look  for  to determine




that a release has taken place and  factors  to  consider  in asses-




sing the potential for releases  to  threaten  human health  and the




environmen t.






II.  POTENTIAL FOR AIR RELEASES  FROM THE  FACILITY




     Three factors are important  in assessing  the potential for




significant air releases from a  facility.   They  are:




     o  unit characteristics, such  as  size,  type and  use;




     o  types of wastes/constituents  in  the  unit; and




     o  potential for mitigating  exposure  resulting from  the release




This section describes each  of  these  factors in  greater detail.






Unit Characteris ti^cs  tha t Af f ec t  the go ten tial  f or  Air  Releases




     When conducting  the site investigation  for  air,  Agency




personnel should assess  both RCRA-regulated  and  non-RCRA  units




and should focus the  investigation  on  operating  units.   Operating




units have the greatest  potential for  air  releases  because they




actively expose wastes to the air on a continuous basis.   Wastes




in closed, inactive units are usually  covered.   There may be some




exposure to the air if a cover  has  eroded  or broken down, but  air




releases resulting from  these situations  are likely  to  be




insignificant.




     When assessing the  potential for  releases,  the key factors




to examine include:
                                6-2

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        unit size.  The size of a unit determines  the  mass  of
        potential contaminants available for  release.   In  addi-
        tion, volatilization  rates are  likely  to  be  larger from
        open units (e.g., surface impoundments  and open tanks)
        with large surface areas and shallow  depths.

     0  purpose of the unit (treatment, storage,  or  disposal).
        In general, units in which active  treatment  is  occurring
        have the greatest potential for air releases.   In  many
        cases,   treatment is designed to promote volatilization  of
        constituents.  In other cases,  this is  not the  main
        purpose of the treatment method in use.   However,  the
        resultant mixing and movement of wastes  leads  to high
        volatilization rates.

     o  design of the unit.  Units in which wastes are  in  direct
        Contact with the a tmosphere have a higher potential  for
        releases than closed or covered units.

     o  current operational status.  The nature  of air  releases
        is such that the majority of the mass  available for
        release will be released shortly after  the waste is
        placed  in the unit.  Thus, as mentioned,  operating units
        are of greater concern than closed units.  This is par-
        ticularly true for unit types and wastes  for which vola-
        tilization is important.  Units with  potential  particulate
        releases may continue  to release contaminants  well after
        closure, especially if the unit has been  poorly maintained.

     o  unit specific factors.  There are  specific design  and oper-
        ational factors associated with each  unit type  which are
        useful  in evaluating  the possible  magnitude  of  a potential
        release.  These factors are summarized  in Table 6-1.

In addition  to considering the individual  unit  sizes,  the

investigator should be aware of the to tal  area  used  for solid

waste.management at a facility.  Although  individual units may

have small releases,  the total release  from a  facility  can be

significant.  Table 6-1 lists  specific  considerations  for

particularly important unit types.

     In assessing a unit's potential for air  release,  the  inves-

tigator should be aware of the importance  of  interactions  between

the various unit characteristics listed above  and the  characteris-

tics of the wastes placed in  the unit.  It is  important to

examine how  these two factors  combine to result in an  air  release.

                               6-3

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                             Table 6-1
                 UNIT POTENTIAL FOR AIR RELEASES
                    AND MECHANISMS OF  RELEASE
Unit Type

Operating Surface
Impound men ts
Open Roofed Tanks
Landfills
Land Treatment Units
Waste Piles
Characteristics and Mechanising  of Release

o  Wastes directly exposed  to atmosphere
   promotes vapor phase emissions
o  Large surface areas and  shallow depths
   promote increased volatilization
o  Mechanical  treatment methods  (such  as
   aeration) increase volatilization

o  Wastes directly exposed  to atmosphere
   (promotes vapor 'phase emissions)
o  Mechanical  treatment or  frequent  mixing
   will increase volatilization

o  Volatilization of vapor  phase constituents
   through the sub-surface  and da ily / perrnanen t
   cover
o  Poor or no  daily cover  increases  volatili-
   zation
o  Open trench fill operations allow direct
   exposure of waste to atmosphere
o  Volatile gases transported by convection
   of biogenic gases released via routine
   landfill venting (particularly important
   in sanitary/hazardous mixed fills)
o  Particulate releases generated by machinery
   during filling operations
o  Particulate releases due  to wind  erosion  of
   cover and/or exposed wastes

o  Wastes normally in direct contact with
   atmosphere
o  Application techniques  which  maximize waste
   contact with atmosphere,  such as  surface
   spreading or spray irrigation promote
   increased volatilization
o  Particulate releases due  to wind  erosion

o  Particulate emissions from uncovered
   waste piles
o  Location of waste pile  in open area with
   no erosion  protection promotes particulate
   genera tion
o  Waste handling activities on  and  arounci
   pile increase emissions
o  Volatile emissions are  likely to  be rare,
   but can occur based on  waste  composition
                               6-4

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Table 6-1 continued


Unit type               Characteristics and Mechanisims of Release

Drum Storage Areas      o  Vaporization from drums frequently left
                           open to atmosphere or from poorly sealed
                           drums.
                        o  Vapor emissions from areas containing  leaking
                           drums

Covered Tanks           o  Volatile releases from pressure venting,
                           poorly sealed access ports, or  improperly
                           operated and maintained valves  and seals.

Incinerators            o  Stack emissions of particulates
                        o  Stack emissions of volatile constituents.
                           High temperatures may cause volatilization
                           of low vapor pressure organics  and metals.
                        o  Volatile releases via malfunctioning valves
                           during incinerator charging

Non-RCRA Wastewater     o  Low concentration wastes may volatilize
Treatment Ponds and        due to large surface area and active waste
Tanks                      treatment.  Releases can be significat
                           releases due to generally large treatment
                           capaci ties

Other Design and        o  Inadequate spill collection systems promote
Operating Practices        intermittent air releases
                        o  Lack of vapor collection systems  for use
                           during container/tank cleaning  operations
                        o  Absence of dust suppression or  particulate
                           control measures
                               6-5

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For example, a facility may have  several  large  operating surface




impoundments, suggesting a potential  for  large  air  releases.




However, if  the facility is a  steel manufacturer  treating only




spent pickle liquor in these ponds, it  is  unlikely  any  air




release will occur because the  hazardous  constituents  in the




waste are non-volatile, soluble metals.




     The following section discusses  the  waste  and  constituent-




specific factors the investigator  should  consider  in assessing  a




waste's potential to release airborne  constituents.






Types of Waste Contained in the Unit




     Only certain hazardous constituents  have a significant




potential for air releases.  This  section  identifies  these con-




stituents and the factors  that  affect  the  magnitude of  their




release.




     Volatile constituents of  concern  for  air releases  include




organic vapors and volatile metals  (e.g.,  arsenic  and  mercury).




Table 6-2 lists a select number of  hazardous  chemical  compounds




which EPA's Office of Air Quality  Planning and  Standards (OAQPS)




considers to be of prime concern  with  respect  to  vapor  phase  air




releas'es.  The table also lists the RCRA  waste  codes  for waste




streams that contain these constituents  to aid  in  their




identifica tion.




     Table 6-3 lists hazardous  constituents that  are  of special




concern for particulate air releases.   Particulate  emissions  from




solid waste management units can  contain  organic  material, heavy




metals, or both.  The heavy metals  shown  in Table  6-2  are




predominantly associated with  particulate  releases,  although





                                6-6

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                              Table 6-2
        HAZARDOUS  CONSTITUENTS  OF CONCERN AS VAPOR RELEASES
  Hazardous  Constituent

Ace taldehyde

Ac role in

Acrylon i trlie

Allylchloride

Benzene

Be nzyl chloride

Carbon Tetrachloride

Chlorobenz eae

Chloro fo rm


Chloroprene

Cresols

Cumene (isopropylbenzene)

1,4-dichlorobenzene

1,2-dichloroethane

Dlchlorome thane

Dioxin

Ep ichlorohydrin

E thylbe nzene

Ethylene  oxide

Fo rmaIdehyde

Hexachlorobu tadiene

Hexachlorocyclopentadiene
           RCRA  Waste  Codes
K001 ,U001

K012

K011 .K012.K013,0009

F024.F025

F024.F025 ,K001 , KOI 4,KOI 9,K083,K085,K103,K105

K015,K085,P028

F001,F024,F025,K016,K016,K020,K021,K073,U211

F001,F002,F024,F025,K015,K016,K085,K105

F002,F024,F025,K009,K010 ,K016 ,K019,K020,
£G73,K02l,K029,U044

F024.F025

F004.U052

U055

F002,F024,F025,K016,K085,K105,U072

KOI 8,KOI 9,K020,K029,K030,K096,F024,F025,U077

F001,F002,F024,F025,K009,K010,K021,U080

F020,F021,F022,F023,F023

K017,KO19,K020,U041

F003

Ul 15

K009,KOIO,K038,K040,U122

F024,F025,K040,K016,K018,K030,U128

F024, F025 ,K032 ,K033 ,'<034 /J130
                                 6-7

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                       Table  6-2  (Continued)
        HAZARDOUS CONSTITUENTS  OF  CONCERN AS  VAPOR RELEASES
  Hazardous Constituent

Hydrogen cyanide

Hydrogen flouride

Hydrogen sulfide

Maleic anhydride

Methyl acetate

N-Dlme thylni trosacnine

Naph thalene

Ni tr obenz ene

Nitrosoraorpholine

Phenol

Pho sgene

Phthalic anhydride

 olychlorina ted biphenyls
   Aroclor 1242
   Aroclor 1248
   Aroclor 1254
   Aroclor 1260

Propylene oxide

1 , 1,2,2-te-jrrachloroethane


Tetrachloroethylene


Toluene

1 , 1 , 1-trichloroethane
Trichloroethylene

Vinylchloride

Vinylidenechlorida

 yl enes
           RCRA Waste Codes
F007,F009,FOIO,K013,K060
K023,K093,U147



U100

F024,F025,K001,K035,K060,K087,U165

F004,K025,K083,K103,U169



K001,K022,K087,U188

P095

K016,K023,K024,K093,K094,U190

K085
F024,F025,K016,K019,K020,K021,K030,K095,
K096.U209

F001,F002,F024,F025,K016,K018,K109,K020,
K021 ,U210

F005,F024,F025,K015,K036,K037,U220

F001,F002,F024,F025,K019,K020,K023,K029,
K073,K095,K096,(J226

F001,F002,rC24,F025,K016,K018,K019,K020,'J22S

K019,K020,K023,K029,K:028,F024,F025,U043

F003,F025,K019 ,K020,?024,K029,U078

F020.U239
                                 6-8

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                            Table  6-3
                   HAZARDOUS  CONSTITUENTS  OF
                CONCERN  AS  PARTICULATE RELEASES
Hazardous Constituent
   Arsenic
   Asbes tos
   Be ry 11 i um
   Cad mium
   Chrorai um
   Lead
   Mercury
   Nickle
       RCRA Waste Codes
DOOO,D004,K060,K021,K084,P010,

P011 ,P012


U013


DOOO,D006,P015


DO00,0006,F006,F007,F008,F009,

F061,F062, F064,F065,F067,F068,F069


DOOO.D007,F006,F007,F003,F009,F002,

F064,F069,F086,


DOOO,D008,?006,F009,K003.K044.K048,

K052,K061,K062,K064,K069  KO86, PI 10


D008.K071,K106


F006,F007,F008,F009
                               6-9

-------
both arsenic and mercury may be  present  as  vapor  phase  releases




due to their relatively high vapor  pressures.   Similarly,  the




organic compounds shown in Table  6-2  may  also  be  found  adsorbed




or bound to soil and/or other particulate matter  releases.




     The investigator should examine  all  available  information on




wastes handled at the facility  to determine  the presence  of  any




of the wastes or constituents referenced  above.






Waste Characteristics that Affect the Magnitude of  Release




     The physical form of the waste contained  in  a  solid  waste




management unit will determine  to a great extent  the  potential




for air releases from the unit.   Wastes  may  be  solid, dilute




aqueous solutions, dilute organic solutions, or concentrated




solutions.   Air releases from solid wastes,  such  as  those  placed




in landfills or waste piles, will be  governed  by  different




principles  than govern releases  from  liquid  wastes.   Liquid




wastes will exhibit potentials  for  air  release  that  depend upon




the strength of the solution and  the  type of solvent  (e.g.,  water




or organic compounds such as oil  or chlorinated solvents)  in  the




unit.




     The concentration of specific  constituents in  each unit  is




another factor governing the potential  magnitude  of  air releases.




The higher the concentration of  a particular constituent  present




in a unit,  the greater is its potential  for  significant air




release.  However, the intrinsic  potential  for  a  constituent  to




volatilize  depends on chemical  and  physical  properties  that  very




greatly between different constituents.   Accordingly, a highly




concentrated solution of one constituent  aiay result  in  a  lower re-




lease potential than a dilute concentration  of  another  constituent.






                                6-10

-------
     As indicated earlier,  the  two  types of  emissions  of  greatest

concern are volatiles and particulates.  Each  type of  emission

has its own set of characteristics  which can help  the  Investigator

assess the potential magnitude  of a release.   These characteris-

tics are discussed below and summarized in Table 6-4,  which

outlines the likely unit types  and  appropriate  parameters  to

consider when evaluating airborne releases from different  types

of waste streams.

     Volatile emissions.  Constituent-specific  physical and

chemical parameters are very Important indicators  of  the  potential

magnitude of a vapor-phase  release.  In some situations,  these

parameters can be used  to develop constants  which  can  provide  the

investigator with a useful  means of quantifying relative  release

potential.  The parameters  most important when  assessing  the

volatilization of a constituent include the  following:

     o  water solubility.   The  solubility in water indicates  the
        maximum concentration at which a constituent  can  dissolve
        in water at a given temperature.  This  value  can  help
        the investigator estimate the distribution of  a constituent
        between the dissolved aqueous phase  in  the unit and  the
        undissolved solid or immiscible liquid  phase.  Considered
        in combination  with the constituent's  vapor pressure,  it
        can provide a relative  assessment of the potential magni-
     --- tude of volatilization  of a constituent from  an aqueous
        environment (see discussion of Henry's  Law constant
        below).

     o  vapor pressure.  Vapor  pressure measures the  pressure  of
        vapor in equilibrium with a pur_e liquid.   It  is best  used
        in a relative sense, constituents with  high vapor  pres-
        sures are more  likely to have significant  releases than
        th.ose with low  vapor pressures, depending  on  other factors
        such as relative solubility and concentrations (I.e.  at
        high concentrations significant releases can  occur even
        though a constituents vapor pressure is relatively low).

     o  octanol/water partition coefficient.   The  octanol/water
        partition coefficient indicates th-e  tendency  of an organic
        constituent to  sorb to  organic constituents in the soil
        or waste matrices of a  unit.  Vapors with  high octanol/
        water partition coefficients will adsorb readily  to  organic


                                6-11

-------
                                Table 6-4
              Parameters and Measures for Use  in  Evaluating
          Potential Air Releases of Hazardous  Waste  Constituents
 mission and Waste Type
A. Vapor Phase Emissions

   -- Dilute Aqueous Solution2/
   -- Cone.  Aqueous Solution^/
   -- Immiscible Liquid
   — Solid
                             Units  of
                             Concern!/
                             Surface  Imp. ,
                             Tanks, Containers
                            Tanks,  Containers,
                            Surface Imp.
                             Containers,  Tanks
                            Landfills,  Waste
                            Piles, Land Trt.
                                                    Useful Parameters
                                                    and Measures
.  Particulate Emissions

  — Solid
                                   Landfills, Waste
                                   Piles, Land Trt.
                                                         Solubility,
                                                         Vapor Pressure,
                                                         Partial Pressure,
                                                         Henry's Law

                                                         Solubility,
                                                         Vapor Pressure,
                                                         Partial Pressure,
                                                         Ra ou1ts Law

                                                         Va po r Pressure ,
                                                         Partial Pressure

                                                         Vapor Pressure,
                                                         Partial Pressure,
                                                         Oc tanol/Wa ter
                                                         Partition  Coeff.
                                                    Particle Size
                                                    Distribution,
                                                    Si te Activi ties,
                                                    Management Methods
   II
   21
Incinerators are not  specifically  listed  on  this  table because
of the unique issues  concerning air  emissions  from  these units.
Incinerators can burn all  the  forms  of  waste listed  in this
table.   the potential for  release  from  these units  is  primarily
a function of incinerator  operating  conditions  and  emission
controls, rather than/waste  characteristics.

Although the octanol/water partition coefficient  of  a  constituent
is usually not an important  characteristic  in  these  waste streams,
there are conditions where it  can  be  critical.  Specifically,  in
waste containing high concentrations  of organic particulars,  con-
stituents with high octanol/water  partition  coefficients will
adsorb to the particulates.  They  will  become  part  of  the sludge
or sediment matrix, rather than volatilizing from the  unit.

Applicable to mixtures  of  volatile components.
                                   6-12

-------
        carbon, rather than volatilizing  to  the  atmosphere.   This
        is particularly important  in landfills and  land  treatment
        units, where high organic  carbon  contents  can  significantly
        reduce the release of vapor phase  constituents.

     o  partial pressure.  For constituents  in a mixture,  particu-
        larly in a solid matrix, the partial  pressure  of  a  consti-
        tuent will be more significant  than  the  pure vapor  pressure.
        In general, the greater  the partial  pressure,  the  greater
        the potential significance of  the  release.   Partial
        pressures will be difficult to  obtain.   However,  when
        waste characterization data is  available partial  pressures
        can be calculated using  methods commonly found in  engi-
        neering and environmental  science  handbooks.

     The investigator should examine each  of  the above parameters

in combination with each other and with the  specific characteris-

tics of the unit of interest.  Several  measures  are  available to

help the investigator with this  assessment,  provided  they  are

applied to the appropriate waste types  and units.   These  measures

include:

     o  Henry's Law constant.  Henry's  law constant  is the  ratio
        of the vapor pressure of a constituent and  its aqueous
        solubility (at equilibrium).   It  can  be  used  to  assess
        the relative ease with which the  compound  may  be  removed
        from  the aqueous phase via vaporization.  It  is  accurate
        only when used concerning  low  concentration  wastes  in
        aqueous solution.  Thus  it will be most  useful when the
        unit being assessed is a surface  impoundment or  tank  con-
        taining dilute wastewaters.  Generally,  when the  value  of
        Henry's Law constant is  less than  10E-7  atm-m^ the  consti-
        tuent will not volatilize  from  water.  As  the  value
     "-.-. increases  the potential  for significant  vaporization
        increases, and when it is  greater  than 10E-3 rapid  vola-
        tilization will.occur.   Henry's Law  constants  for  many
        potentially significant  constituents  are listed  in  table
        6-2.

     o  Raoult's Law -  Raoult's Law can  be  used to  predict re-
        leases from concentrated aqueous  solutions  (i.e.  solutions
        over  10% solute).  This  will be most  useful  when  the  unit
        of concern entails container storage,  tank  storage,  or
        treatment of concentrated  waste streams.

     For solid wastes, imiscible liquids,  and  wastes disposed of

in landfills, land treatment, or waste  piles  there  are no  simple

measures that can be used to assess the potential  for  volatilization
                               6-13

-------
of a constituent.  The  investigator will  need  to  consider the

appropriate chemical, physical, and unit  parameters,  and  then  use

his/her best judgment in determining  the  potential  for release.

Table 6-4 summarizes the chemical  parameters  the  investigator

should consider when assessing  the different  waste  physical

form/unit combinations.


     Particulate emissions.  The  likelihood of  particulate  re-

leases at hazardous waste management  facilities  is  generally

associated with landfills, land  treatment units  and/or waste

piles.  The severity of particulate releases  is  governed  by

different parameters than those  that  affect vapor-phase releases.

The primary physical parameter will be  the particle size  distri-

bution.  Incinerators will always  release some  particulates  in

the exhaust stack, and  they may cover a wide  range  of sizes.

Information on the particle size  distribution  can be  helpful  in

assessing the potential risks  to  humans,  as the  primary concern

will be with the smaller, iahalable particulates.

     Three mechanism are particularly important  in  the generation

of particulate releases at hazardous  waste facilities, and  the

investigator should examine the site  for  evidence that these

practices are occurring.  They are:

     o  wind erosion;   In general, the  unit's  location will
        affect the potential for  the  wind to  erode  wastes in  the
        unit.  The unit's location and  orientation  with respect
        to the prevailing winds and large structures  on site  will
        determine the unit's vulnerability to  wind  erosion  and-
        the potential for particulate releases.   Agency personnel
        should determine the location of  SWMUs  of concern with
        respect to prevailing  winds and  the use  of  wind screens
        (both natural and man-made) and daily  covers  to determine
        the unit's vulnerability  to wind  erosion.
                               6-14

-------
     o  reentrainment by moving vehicles  on  soil,  paved,  and
        unpaved roads:  Vehicles moving on site  can  generate
        fugitive dust emissions.   Factors affecting  dust  emissions
        generation include  the amount of  daily vehicular  traffic
        at the site and the average  size  of  the  vehicles.

     o  operational activities: These include  the  movement  of
        soils or hazardous  wastes  by dozers,  loading by  front-.end
        loaders, and other  activities associated with landfilling
        or waste piles may  cause fugitive dust emissions.
Potential for M 1 tigating Exposure

     In assessing  the potential  significance  of  air  releases  from

a solid waste management unit or a  facility with  several  units,

the investigator needs  to consider  several  factors  that act  to

reduce the concentrations of airborne contaminants.   Two  classes

of factors are important:

     o  atmospheric/geographic conditions,  which  are directly
        related to the  amount of atmospheric  dispersion available
        for contaminant dilution; and

     o  contaminant specific factors, such  as  decay  rates  and
        particulate size.

Both of these factors can significantly  reduce the  concentration

of released constituents, thereby reducing  the importance  of  a

release.   However, under some specific conditions,  the  effect  of

these.factors is limited considerably.

     Atmospheric/geographic factors.  Atmospheric dispersion  can

rapidly dilute the mass of a contaminant  released from  a  solid

waste management unit.  In many  cases, a  contaminant's  concentra-

tion decreases as  the distance from  the  source of release  in-

creases.   However, specific atmospheric  conditions  and  geographic

factors can greatly limit the amount of  dispersion.   When  asses-

sing air  releases, the  investigator  needs  to  consider whether  any

of these  conditions are important at the  site  in  question.
                               6-15

-------
Conditions and factors that limit  dispersion  include:

     o  narrow valleys and urban areas containing  large  buildings
        (artificial canyons);

     o  areas dominated by off-shore breezes;

     o  areas with atmospheric conditions  dominated  by neutral
        air stability; and

     o  areas with atmospheric conditions  known  to frequently
        result in inversions (low  average  wind speeds, mountain
        bas ins,  etc.

All of these conditions contribute  to higher  than  normal  concen-

trations,  thus increasing the significance of a  release.   The

investigator may be able  to obtain  some  of this  information  from

local weather data bases as part of  the  preliminary  assessment.

However,  collection of this information  will  probably  require a

site inspection.


Constituent-Specific Factors

     Two  important constituent-specific  factors  can  also  affect

the airborne concentration of a released contaminant.  For vapor

phase contaminants, persistence is  the most  important  factor, and

for particulate  contaminants, particle size  is the principal

conce rn.

     The  persistence of an airborne  contaminant  is primarily

governed  by a constituent's photolysis rate.  Pollutants  with

high photolysis  rates (i.e., those  with  an atmospheric half-life

of 1 day)  will degrade rapidly, resulting  in  a significant

decrease  in concentration and therefore  exposure.

     For  particulate releases, the  size  distribution of  the

particles in the release plays an  important  role in  both  dispersion

and actual exposure.  Large particles will settle  out  of  the air

more rapidly than small particles,  thus  they  will  not  travel as

                               6-16

-------
far off-site or be diluted  as  much  by  dispersion.   Very  small




particles (i.e., those  that are  less  than  5  microns  in  diameter),




are considered  to be  respirable  and  thus  present  a  greater health




hazard than larger particles.  Particulate  releases  containing a




high proportion of small  particles  are  therefore  of  greatest




concern.   The inspector should examine  the  source of the  parti-




culate emissions to obtain  information  on  particle  size.






III.  EVIDENCE OF AIRBORNE  RELEASES




     Positive identification  of  airborne  contaminants  at  a site




is an important part  of determining  whether  a  significant air




release has occurred.   However,  because air  releases are  difficult




to observe and monitor, it  will  generally  be difficult  to make a




positive identification.  In  addition,  it  Is doubtful  that




adequate monitoring data  will  be  readily  available  for  a  specific




site.  The investigator will  most likely  have  to  rely  on




circumstantial evidence based  on  available  data,  or, in  some




cases, on sampling data collected during  the site  investigation.






Available Data Co 1leetion Methods and  Sources




     The most useful  information  for  determining  if  a  release is




or has occurred is on-site  monitoring  data.  As mentioned above,




It is unlikely  that this  type  of  information will  be available




for most sites.  Sources  of  this  information Include the  owner or




operator, EPA regional  offices,  state,  county  or  local  departments




of health, or OSHA.   Even If  this Information  is  available,  the




investigator should carefully  assess  its  usefulness, paying




particular attention  to proper collection  of background  samples




and the time and weather  conditions  when  samples  were  taken.






                               6-17

-------
     Other useful data  includes citizen  complaints  concerning  both




odor and observed particulate emissions.   It  is  important  to note




however, that the absence of odor  does not  imply  the  absence of




vapor releases,  since many constituents  have  high odor  thresholds.




OSHA may have, in addition to air  monitoring  data,  collected




health or personal monitoring data  from  site  workers.   This




information may also  suggest the presence  of  a  release.






The RQ1e o f S a m p 11 n g




     EPA expects that in most cases,  sampling will  not  be  neces-




sary during the PA/SI to determine  whether  to conduct further




investigations at the unit for air  releases.  However,  there may




be situations where  the  investigator  may want to  take samples  or




require the owner or  operator to take samples.   For example,




the investigator may  wish to obtain specific  information on  the




types and concentrations of specific  hazardous  constituents  in




the unit to get a better indication of the  potential  magnitude of




an air release.   Another reason to  conduct  sampling would  be  to




confirm a finding that  a release or a potential  air release  from




the unit warrants further investigation.




     The permit writer  may choose  to  use monitoring equipment,




such as an organic vapor analyzer  or  a forced air particulate




filter, around the perimeter of the unit to  confirm a suspected




release from a unit.  However, without the  proper collection of




background samples as well as time  series  sampling, the use  of




such monitoring equipment during the  course  of  a  site inspection




can not confirm that  a  release is  not taking  place.




     The investigator can require  the owner  or  operator to sample




or monitor in certain situations.   These are  likely to  be  situa-




                               6-13

-------
tions where the Agency can specify  the  number  and  location of




samples, sampling or monitoring  methods,  and  the  procedures  for




analyzing samples.






IV.  POTENTIAL FOR EXPOSURE




     Exposure information, to  the extent  It  Is available  for the




facility, will help in assessing whether  and  to what  extent  air




releases from the facility could affect human  health  and  the




environment.  Again, at this stage  in  the  corrective  action




process, the information and the analysis  will largely  be quali-




tative.   However, this information  can  help  in determining the




need to conduct further investigations, (e.g., depending  on  the




population density around the  site); and  in  setting priorities




for the remedial  investigation stage of the  process.




     Population density and distance from  the  source  are  the pri-




mary factors in determining the  significance  of a  potential




exposure.  Distance should be  measured  from  the unlt(s) containing




the waste rather  than from the facility boundary,  although total




facility emissions from all solid waste management units  must




also be kept in mind.  Most Importantly,  the  investigator should




consider the density of the population  residing within  an approxi-




mately four-mile  radius, as well as transients such as  workers in




factories, offices, restaurants, motels,  or  students.   Travelers




that pass through the area should not  be  included  in  any  count.




     The most significant exposure  potential  will  occur  in situa-




tions when  there  is a high population  density  within  a  1/4 mile




radius of the site.  However,  because  concentrations  can  be  quite




high, even low density populations  in  such close  proximity to   the




site are of concern.  Dispersion can significantly reduce concen-




                                6-19

-------
trations as distance  from a  site  increases.   Thus,  the  signi-

ficance of high population density  at  larger  distances  from  the

site is reduced, particularly  when  the  distance  is  four miles  or

mo re.

     The investigator  needs  to consider  the  relationship between

distance, concentration, and population  density  in  evaluating  the

significance of an exposure  potential.   An additional  factor to

consider is the population located  along  the  line of  the most

predominant wind direction at  a  site.   Because  the  PA/SI is

primarily concerned with continuous  releases,  populations  located

along this line downwind of  the  site are  more likely  to receive

significant exposures  than populations  located along  other  vectors.

     If the investigator determines  that  a solid waste  management

unit is releasing large volumes  of  unsaturated hydrocarbons,

he/she may need to consider  population  density over a  much  larger

area than a four mile  radius.  These constituents contribute to

the  formation of photochemical smog  and  ozone, which,  in combina-

tion with other regional pollutant  releases,  can cause  significant

exposures over a wide  geographic  area.


V.  SUMMARY

     This chapter has.identified  a  number  of  factors  that  affect

a facility's potential  to have significant air releases that

warrant further investigation.   These  factors include:

     o  unit characteristics,  such  as  size,  type and  use;

     o  types and characteristics of wastes  placed  in  the  unit; and

     o  the potential  of locational  factors  and  constituent-specific
        factors to mitigate  the  significance  of  the release.

The first section of  this chapter described  all  of  these factors


                                6-20'

-------
in some detail in order  to give  the  investigator  a  better basis




for determining whether  a release  is significant  or  not.   While




many units can be expected to have air  releases,  most  of  these



releases -- either because of certain unit  characteristics,




concentrations of specific constituents  in  the  waste,  atmospheTic




dispersion characteristics, distance to  receptors,  etc. --



will not be significant  enough  to  warrant  further investigation.




The investigator will need to consider  each  of  the  factors




described In Section I of this  chapter  in  determining  the potential




for significant releases from solid  water  management units at  the




facili ty.




     The investigator should use evidence  (to  the extent  it  is




available) that identifies the  presence  of  releases  and informa-




tion on the potential for human  exposure to  assist  in  making




these determinations.




     Table 6-5 provides  examples of  situations  that  are likely  to




require further Investigation and  situations  that probably will




not require further  Investigation  for air  releases.
                               6-21

-------
                              Table 6-5
                          Uni t Illustrations
Unit Type

Surface
  Impoundmen ts
  (RCRA and non-
   RCRA)
Further Investigation
Needed	

Surface impoundments
that contain large
quantities of highly
volatile wastes listed
in Table 6-2
Further Investigation
Not Needed	

Units closed by removal
of wastes

Units handling waste-
waters containing only
non-volatile metals
Open Roofed
  Tank s
Landfills
Open tanks containing
large, quantities of
highly volatile wastes
listed in Table 6-2

Landfills with inade-
quate daily cover and
compaction operating
procedures in areas
with strong prevailing
winds in close prox-
imity to populations
Units treating or
storing wastewaters
containing only
non-volatile metals

Monofills of wastes
which contain only
non-volatile metals
and which use daily
cover and compaction
to control particulates

Monofills of wastes
containing only organic
constituents having
high oc tanol/wa ter
partition coefficients
and which use daily
cover and compaction
to control particulate
emi s s ions
                                              Small landfills  closed
                                              in  accordance  with
                                              closure provisions
                                              in  §264.310

                                              Units which  have been
                                              closed for a  long
                                              .period of time and
                                              that are being man-
                                              aged using a  stable
                                              cover system
                                  6-22

-------
Table 6-5 cont.


I
Unit Type

Land Treatment
Waste Piles
Drum 3 torage
  Areas
Covered Tanks
Inci nera tors
            II
Further Investigation
Needed	

Land treatmet units
containing large quan-
tities of highly vola-
tile wastes described
in Table 6-2 and located
in areas with strong
prevailing winds and
nearby populations

Outdoor, uncovered waste
piles receiving large
quantities of wastes
described in Table 6-3
Outdoor storage areas
poorly maintained with
evidence of frequent open
drum storage, poorly
sealed drums, and/or
leaking drums containing
wastes described in Table
6-2.
Poorly maintained units
containing cracks,
corrosion, or poorly
sealed access ports
which contain large volumes
of highly volatile wastes
described in Table 6-2

All unpermitted units
Further Investigation
Not Needed	

Closed units which
were used experi-
mentally or for. a
single application
of wa s te and for
which wind erosion
controls are being
used

Most indoor piles

Outdoor piles properly
covered, located in
areas which minimize
wind erosion, and
which contain only
constituents with very
low vapor pressures

Most indoor storage
areas

Well maintained out-
door storage areas
in which was tes
containing low vapor
pressure constituents
are stored

Most covered units
Well maintained and
permitted Incinerators
with inspection
records detailing
proper operation
    By design all  incinerators  release  gases  and  some  particulate matter
    Into the atmosphere.  The  investigator  should thoroughly  investigate
    all units for  improper and  hazardous  releases.
                                  6-23

-------
APPENDIX MATERIAL

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-------
                              LIST  31

                   INDUSTRY SPECIFIC  PARAMETERS
                           METALFINISHING
      Parame ter
ch romi urn
copper
cyanide
Iron
zinc
trichloroe thene
tetrachloroethylene
vinyl c hlor ide
p henan threne
nickel
Chemical Abstract System Number

            7440-47-3
            7550-50-3
            57-12-5
            7439-89-6
            7 44 u-6 6 - 6
            79-01-6
            127-18-4
            75-01-4
            85-01-8

-------
                         LIST B2

                      IRON AND STEEL
     Parame te r
arsenic
ch romi urn
cyan ide
tin
zinc
benzene
benzo(a)pyrene
tetrachloroethylene
Chemical Abstract System Number

           7440-38-2
           7440-47-3
             57-12-5
           7440-31-5
           7440-66-6
             71-43-2
             50-32-3
            127-18-4

-------
                              LIST  B3

                             PESTICIDES
           Pa rame ter	     Chemical  Abstract  System  Number
   arsenic                                 7440-38-2
   cyanide                                   57-12-5
   copper                                  7550-50-8
   benzene         .                          71-43-2
   carbon tetrachloride                      56-23-5
   chlordane                                 57-74-9
   chiorobenzene                             67-66-3
   chloroform                               108-90-7
   1,4-dichlorobenzene                      106-46-7
   2,4-dichlorophenol                       120-83-2
   heptachlor                                76-44-8
   hexachlorocyclopentadiene                 77-47-4
   methyl chloride                           74-87-3
   metbylene chloride                        75-09-2
   4-nitrophenol                            100-02-7
   phenol                                   103-95-2
   tetrachloroethylene                      127-13-4
   coluane                                  103-33-3
   Manufactured oesticides*
* A n y specific pesticides,  residues,  off-specification  products,
 or other sixiliar items known  to  have  been  disposed  ot  at  the
 sit-e,  or, in the case of  a dedicated  facility,  known  to have  been
 manufactured at the site.

-------
                               LIST  C
         Parameter               Chemical  Abstract  System Number

bis(2-ethylhexyl)phthalate                 117-81-7
PCB-1016                                   12674-11-2
PCB-1221                                   11104-28-2
PCB-1232                                   11141-16-5
PCB-1248                                   12672-29-6
PCB-1254                                   11097-69-1
PCB-1260                                   11096-82-5
PCB-1242            '                       53469-21-9
arsenic                                    7440-38-2
benzene                                    71-43-2
ch lorobenzene                              108-90-7
ethyl benzene                              100-41-4
toluene                                    108-88-3
chromium                                   7440-47-3
copper                                     7550-50-8
cyanide                                    57-12-5
tetrachloroethylene                        127-18-4
vinyl chloride                             75-01-4
trichoroethylene                           79-01-6
Iron                   -                    7439-89-6
manganese                                  7439-96-5
naphthalene                                91-20-3
nickel                                     7440-02-0
phananthrene                               is 5 - 0 1 - 3
phenol                                     108-95-2
Tine                                       7440-6-6

-------
         Parame ter
3,3'-dichlorobenzidlne
be nz idene
endrin a Idehyde
bis(2-ethylhexyl)phthalate
bu tylbenzylphthalate
d 1-n-butylphthala te
di-n-octylphthalate
diethylphthala te
dimethylphthalate
hexachlorobutadiene
hexachlorocyclopentadiene
aldrin
M - n i trosodi-n-propylamlne
heptachlor expoxide
dieldrin
endrin
2-bu tanone
i sophorone
ace tone
acrolein
acrylonitrile
hep tachlor
chlordane
alpha-endosulfan
be ta-endosulfan
endosulfan sulfate
fluroene
aeenaphthaline
a cena ph thene
vinyl acetate
aluminum
anthracene
ant itnrony
PCB-1016
PCB-1221
PCB-1232
PCB-1248
PCB-1254
PCB-1260
PCB-1242
arsenic
ba r i urn
benzo(a)anthracene
3 ,4-benzofluoranthene
N-ni trosodiphenyla.nine
benzene
4,4'-DDE
4,4'-DDD
1 , 2,4-trichlorobenzene
1 ,2-dichlorobenzene
                              LIST D
Chemical Abstract System Number

          91-94-1
          92-87-5
          7421-93-4
          117-81-7
          85-68-7
          84-74-2
          117-84-0
          84-66-2
          131-11-3
          87-68-3
          77-47-4
          309-00-2
          621-64-7
          1024-57-3
          60-57-1
          72-20-8
          78-93-3
          78-59-1
          67-64-1
          107-02-8
          107-13-1
          76-44-3
          37-74-9
          115-29-7
          115-29-7
          1031-07-8
          3 o - 7 3 - 7
          ZJ'S-^o-j
          83-32-9
          103-05-4
          7429-90-5
          120-12-7
          7440-36-0
          12674-11-2
          11104-23-2
          11141-16-5
          12672-29-6
          11097-69-1
          11096-32-5
          53469-21-9
          7440-38-2
          7440-39-3
          56-55-3
          205-99-2
          86-30-6
          71-43-2
          72-55-9
          72-54-8
          120-82-1
          95-50-1

-------
                         LIST  D  (Continued)
         Parame ter
1,3-dichlorobenzene
1,4-dichlorobenzene
4,A'-DDT
4-bromophenylphenylether
4-chlorophenylphenylether
2,4-d in i trotoluene
2,6-dinltrotoluene
c hiorobe nzene
e thylbenzene
hexachiorobenzene
toluene
ni trobenzene
benzo(a)pyrene
benzo(ghi)perylene
benzo(k)fluoranthene
beryllium
cadmi urn
caIc i urn
carbon disulfide
chromi urn
ch ry sene
cobalt
copper
cyan ide
alpha-sac
beta-BHC
del ta-3HC
ga.n.-.a-3HC
dibenzo(a,h)anthracene
2,3,7,8-TCDD
bis(2-chloroethoxy)me thane
bis(2-chloroethyl)ether
1,1, 1 "r,trichloroe thene
1,1,2,2-tetrachloroethylene
1,1,2-trIchloroethene
1,1-dichloroethene
1  , 2-dichloroe thene
c hio roe thane
hexachloroethene
2-chloroethylviny1 ether
1, 1-dichloroethylene
1,2-dichloroethylene
vinyl chloride
tetrachloroethylene
t  r ichloroe thene
flouroan thene
1,2-diphenylhydrazine
indeno(l,2,3-cd)pyrene
iron
lead
Chemical Abstra c t System Number

           541-73-1
           106-46-7
           50-29-3
           101-55-3
           7005-72-3
           121-14-2
           606-20-2
           108-90-7
           100-41-4
           118-71-1
           108-88-3
           98-95-3
           50-32-8
           191-24-2
           207-08-9
           7440-41-7
           7440-43-9
           7400-70-2
           75-15-0
           7440-47-3
           213-01-9
           7440-48-4
           7550-50-3
           57-12-5
           319-34-b
           319-85-7
           319-S6-S
           53-3J-S
           53-70-3
           1746-01-6
           11 1-91-1
           111-44-4
           71-55-6
           79-34-5
           79-00-5
           75-34-3
           107-06-2
           75-00-3
           67-72-1
           110-75-8
           75-35-4
           156-60-5
           75-01-4
           127-18-4
           79-01-6
           206-44-0
           122-66-7
           193-39-5
           7439-89-6
           7439-97-6

-------
                        LIST D  (Continued)
         Parameter
ma gne s I urn
manganese
me rcu ry
n-ni trosod ime thylamine
me thyl bromide
dichlorobromomethane
methyl chloride
chlorodibromomethane
methylene  chloride
dichlorodifluoromethane
carbon tetrachloride
bromo fo rm
chloroform
trichloro fluoromethane
naphthalene
2-chloronaphthalene
nickel
phenan threne
phenol
2,4,5-trichloropnenol
2,4,6-trichlorophenol
2,4-dichlorophenol
2 , 4-d i me thylphenol
2 , 4-d in i trophenol
2-chlo rophenol
4,6-dini tro-o-cresol
2-n i t rophenol
p-chloro-m-cresol
4-me thylphenol
4-ni trophenol
pentachlorophenol
po tass i urn
1,2-dichloropropane
bis(2-chloroisopropylether)
1,2-dichloropropylene
p y r e n e
selenium
s ilve r
sodium
thalli urn
tin
toxaphene
va nad iurn
zinc
Chemical Abstract System Number

           7439-95-4
           7439-96-5
           7439-97-6
           62-75-9
           74-33-9
           75-27-4
           74-87-3
           124-48-1
           75-09-2
           75-71-8
           56-23-5
           75-25-2
           67-66-3
           75-69-4
           91-20-3
           91-53-7
           7440-02-0
          -35-01-8
           108-95-2
           95-95-4
           88-06-2
           120-83-2
           105-67-9
           51-2S-5
           95-57-8
           534-52-1
           83-75-5
           59-50-7
           106-44-5
           100-02-7
           87-86-5
           7440-09- 7
           78-87-5
           39633-32-9
           542-75-6
           129-00-0
           7782-49-2
           7440-22-4
           7440-23-5
           7440-28-0
           7440-31-5
           8001-35-2
           7440-62-2
           7440-66-6

-------
             SAMPUNG PRIORITIES FOR ENVIRONMENTAL POLLUTANTS
 Compounds  are characterized on the basis  of persistence,  accumulative capacity and
 volatility.   "X" indicates  the  appropriate  environmental  compartments)  for  initial
 sampling.
                                                  Environmental Compartment
             Compound
Water
Sediment
Biota
METALS AND INORGANICS

Antimony
Arsenic
Asbestos
Beryllium
Cadmium
Chromium
Copper
Cyanides
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc

PESTICIDES

Acrolein
Aldrin
Chlordane
000
DOE
DOT
Dieldrin
Endosulfan and endosulfan sulfate
Endrin and endrin aldehyde
Heptachlor
Heptachlor epoxide
Hexachlorocyclohexane (a,8,5 isomers)
Y-Hexachlorocyclohexane (lindane)
Isophorone
TCDO
Toxaphene
  X

  X
  X
  X
  X
  X
               X
               X
               X
               X

               X
               X
               X
               X
               X
               X
               X
   X
   X
   X
   X
   X
   X
   X
   X
   X
   X
   X

   X
   X
                X
                X
                X
                X

                X
                X
                X
                X
                X
                X
                X
 X
 X
 X
 X
 X
 X
 X

 X
 X
 X
                           X
                           X

-------
                                         D
                                                            WPF 2/1/85
                                                            Page 9 of  11
                   REFERENCED STANDARD OPERATING
                   GUIDELINES FOR PROJECT ACTIVITIES
Please check off the following tasks that will be performed during the course of
the project.  Then, at the bottom of the page and on subsequent pages, describe
fully, for each task, the appropriate procedures and actions that will be taken
to provide both quality assurance and quality control.  If a given task has
standard operating guidance (SOG) that is documented, please refer to that
guidance.  The primary reference  would be State Agency Standard Operating
Procedures.  List others as appropriate.

           Document/Section           Description

         	Ambient Air Sampling (OVA, HNU, etc.)

         	 Ground-Water Sampling

         	 Surface-Water Sampling

         	Soil/Sediment Sampling

         	 Tap Water Sampling

         ___________________ Land Surveying

         	 Electrical Resistivity Survey

         	Electromagnetic Survey

         	 Magnetometer Survey

         	 Metal Detection Survey

         	 Ground Penetrating Radar Survey

         	'    Seismic Survey

         	 Water Level Measurements

         	 Perimeter Survey

         	Site Inspection

         	Soil Borings/Well Installation

         	Bedrock Fracture Analysis

         	 Pump/Permeability Tests

         	Preparation of Water Table  Maps

                             Preparation of Bedrock Contour Maps

-------
                                                            WPF 2/1/85
                                                            Page  11 of 11
                              APPLICABILITY
The folk>wing portions of the NUS Superfund Division Quality Assurance Manual
are applicable to the performance of specific work elements defined in
TDD /MM  i"o StaVe. • The quality assurance procedures recognized in Region II
FIT follow applicable operating guidelines provided in the preeceeding section of  •
this work plan.
       ( )   Number           	Subject	
       	  QAP 2.5         Work Plans
       	  QAP 3.1         Control of Remedial Design Activities
       	  QAP 4.1         Field Data Collection
       	  QAP 4.2         Data Reduction, Validation, and Reporting
       	  QAP 5.1         Preparation of Procurement Documents
       	  QAP 5.2         Subcontractor Quality Assurance Requirements
       	  QAP 6.1         Preparation of Instructions and Procedures
       	  QAP 7.1         Identification of Controlled Evidentiary
                              Documents
       	  QAP 7.2         Issuance and Distribution of Controlled
                              Documents
       	  QAP 7.3         Development, Documentation, Verification, and
                              Retention of Software Programs
       	  QAP 7.4         Technical Reports
       	  QAP 7.5         Interim Document Review  Procedure
       	  QAP 8.1         Control of Procurement Activities
       	  QAP 8.2         Evaluation and Selection of Subcontractors
       	  QAP 9.1.F2       Chain of Custody
       	  QAP 9.2.F2       Sample Control
       	  QAP 10.1         Analysis Techniques
       	   QAP 11.1         Off site Reconnaissance
       	  QAP 11.2         Onsite Inspections
       	  QAP 12.1         Implementation of Measuring and Test Equipment Controls
                              Materials
       	   QAP 13.1         Packaging, Marking, Labeling, and Shipping of
                              Samples  from Hazardous-Waste Sites
       	  QAP 14.1         Nonconformance Reporting, Evaluation, and
                              Disposition
       	   QAP 15.1         Implementation and Documentation of Corrective
                              Actions
       	   QAP 16.1         Storage and Retrieval of Quality Assurance
                              Records
       	   QAP 17.4         Preparation for Audit
       	   QAP 17.6         Quality Notices

-------
 SAMPLING PRIORITIES FOR ENVIRONMENTAL POLLUTANTS
 PAGE THREE
             Compound
   Environmental Compartment
Water      Sediment       Biota
ETHERS (Continued)

8is(2-chloroisopropyl)ether
2-Chloroethyl vinyl ether
4-Chlorophenyl pnenyl ether
4-Sromopheny! phenyl ether
Bis(2-chloroethoxy) methane

MONOCYCUC AROMAT1CS

Benzene
Chlorobenzene
1,2-Dichlorobenzene (o-dichlorobenzene)
1,3-Dichlorobenzene (m-dichlorobenzene)
1,4-Oichlorobenzene (p-dichlorobenzene)
1,2,4-Trichlorobenzene
Hexachlorobenzene
Ethylbenzene
Nitrobenzene
Toluene
2,4-Oinitrotoluene
2.6-Dinitrotoluene

PHENOLS AND  CRESOLS

Phenol
2-Chlbrophenol
2.4-Oichlorophenol
2.4,6-Trichlorophenol
Pentachtorophenol
2-Nitrophenol
4-Nitrophenol
2.4-Oinitrophenol
2.4-Oimethylphenol
p-Chloro-m-cresol
4,6-Dinitro-p-cresol
  X
  X
  X
  X
  X
X
X
X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
               X
                            X
                            X
             X
             X
             X
             X
             X
             X
  These compounds have been removed from the EPA priority pollutant list

-------
                        EXPENDABLE EQUIPMENT


                                   Quantity                 Amount
                                   Packag
Item                               Packaged                 Required
CHEMICALS

Acetone                            5 gal.
Acetone                            1 gal.
Trichloroe thane                      5 gal.
Trichloroethane                      1 gal.
Methylene-chloride                  5 gal.
Methylene-chloride                  1 gai.
Hexane                             1 gal.
Gasoline                            1 gal.
Gasoline                            5 gal.
Nitric Acid                          1 gal.
Nitric Acid                          5 ml.
Sodium Hydroxide                    1 liter
Motor Oil                           I qt.
2-Cycle Oil                          1/2 pt.
Alconox                             1 gal.
Baking Soda                         2 Ib. box
SAMPLE CONTAINERS

*0 ml. VOA Bottles                   1 each
Yt gai. Amber Bottle                  1 each
I liter Amber Bottle                  1 each
S oz. Glass Jars                      1 each
1 liter Plastic Bottles                1 each
Plastic Bags S" x 12"                  100 box
Plastic Bags 10" x 12"                100 box
Plastic Bags 12" x 20"                100 box
Paint Cans w/lid dc snaps              1 gal.
Paint Cans w/lid 
-------
                     EXPENDABLE EQUIPMENT (Conf d)
                                   Quantity                 Amount
 Item                              Packaged                Required


 FILM

 C-13J-36-100-Prints                 I roll                    	
 C-l 35-36- 200-Prints                 1 roll                    ZZHHZ
 C-135-36-400-Prints                 1 roll                       3.
 C-l 35-2*-100-Prints                 1 roll
 C-135-20-200-Prints                 l roll                    H~~'
 C-l35-2*-400-Prints                 1 roll                    HUZZ
 C-135-l2-100-Prints                 i roll                    ZZIZZ
 C-135-l2-200-Prints                 l roll                    ZZZZZ
 C-13M2-*00-Prints                 1 roll                    ZZZZH
 C-135-36-20Q-Slide                  1 roll                    	
 C-135-36-25-SUde                   1 roll                       £j_
 BAW-l35-20-400-Prints              I roll                    	
 SX-70 Polaroid                      I sgl. pack               	
 Kodamatic                          l sgl. pack               	
STATIONERY SUPPLIES

Graph Paper
Manilla Tags
Paper Towels
Felt Tip Markers
Ball Point Pens
Indelible Ink Pens
ROPE

Nylon 3/16"                        600'roll
Nylon \l<4"                         1000' roll
Manila I/*                         100' roll
Manila 1/2                         50' roll
TAPE

Clear Plastic                        l each
Duct                                1 roil
Elec. Vinyl                          l roll
Filament                            1 roll
Flagging                            100' roll
Masking                             1 roll
Transparent                         l each

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                            NON-EXPENDABLE EQUIPMENT


       Equipment                                 Amount Required
CAMERAS

Cannon AEi
Polariod One Step
Polaroid SX70
Camera bag
Binoculars
AIR MONITORING

HNU Photoionization Detector
Draeger Tubes               Type /* <^w -> ^? g       q
Organic Vapor Analyzer                                 /
OVA Chart Recorder                                ____
Explosimeter                                         /
Combination Explosimeter and O? Indicator            	
Oxygen Indicator                                      /
Draeger Tube Hand Pump     '                          /
H2S Gas Indicator                                     /
Mercury Sniffer                                    ______.
Photovac
METERS

Radiation Mini-Alert
Conductivity Meter
pH Meter
Resistivity Meter (Bison)
Resistivity Meter (Soil Test)
Metal Detector
SURVEYING EQUIPMENT

Optical Rangefinder
Level, Hand 2X
Brunton Transit w/case
Compass
200' Fiberglass Measuring Tape
300' Fiberglass Measuring Tape

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                       NON-EXPENDABLE EQUIPMENT (conf d)
       Equipment                               Amount Required
POWER EQUIPMENT

Digger Mobile
3 HP Water Pump w/gas can
Generator w/gas can
Power Auger w/gas can
Extension Cord-Heavy Duty 100"
Extension Cord-Light Duty 25"
Remote Drum Opener
PERSONAL PROTECTION

Hard Hat
Safety Goggles
Safety Glasses
Splash Shield
Full Face Respirator
Respiratory Cartridges
Butyl Rubber Apron
Encapsulated Suits
Life Vests
Rain Jacket
Rain Pants
SELF CONTAINED BREATHING APPARATUS

401 SCBA
Dual Purpose SCBA                                   <*"
CASCADE System                                	~
45 cu. ft. Composite Tanks   :                        / Q
Umbilical Breathing Air Lines (50* Sec)              	
Umbilical Breathing Air System                     	
330 cu. ft. Class "D" Breathing Air Cylinder          	
STANDBY SAFETY EQUIPMENT

20// Fire Extinguishers
Oj Resuscitator
Stretcher
Eye Wash
Trauma Kit

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t
                        UNITED STATEbE-'V-rNMENTAl. PROTECTION AGENCY        Pa'e^M-S
                                    ,V ASH .NO TON  DC 20460


                                        NOV  I 9 JS84
                                               iOUlO WASTE ANO *•."*• -Gc'tC ' *«.'•

MEMORANDUM

SUBJECT:  Standard Operating Safety Guides, November  1984

FROM:     William N. Hedeman, Jr., Director
          Office of Emergency and Remedial R

TO:       Regional Office Addressees

     The enclosed Standard Operating Safety Guides, November  1984
replaces the Interim Standard Operating Guides, Revised
September 1982.  The Guides have been updated  and revised  to
reflect additional experience EPA personnel have gained  in
responding to environmental incidents involving hazardous
substances.

     The Standard Operating Safety Guides are  in accordance and
consistent with the procedures for employee health and safety
contained in EPA's Occupational Health and Safety Manual,
Chapter 9, Hazardous Substances Responses, (1440 TN12).
May 5, 1984.

     The guides are not meant to be a comprehensive safety
manual for incident response.  Rather, they provide information
on health and safety to complement professional judgement  ar.d
experience,  and to supplement existing Regional office safety
procedures.

     If you have any questions or comments concerning the
guides, please contact Mr. Stephen Lingle, Director,  Hazardous
Response Support Division or Mr. J. Stephen Dorrler,  Chief,
Environmental Response Tea™.

Enclosure

Addressees

Director, Ofc. of Emergence & Remedial Resp. ,  Region  II
Director, Hazardous Waste Mgmt. Div., Region III
Director, Air & Waste Management Division,
          Regions IV, VI, VII. VIII
Director, Waste Mgmt. Div., Regions I & V
Director, Toxics & Waste Mgmt. Div., Region IX
Director, Air & Waste Division X

cc: Gene Lucero, OWPE
    John Skinner, OSW

                                  M-3

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                                                                       1/11/85
                                                                 Jew Paqe M-5
      -  Address   emergency  medical  care  for injuries  and toxicological
         problems.

      -  Describe requirements  for  an environmental  surveillance  program..

      -  Specify  any routine and special training required  for  responders.

      -  Establish procedures for protecting  workers  from  weather-related
         problems.


III.   SITE SAFETY PLAN  SCOPE AND DETAIL

      The plan's  scope, detail,  and  length  is  based on:

      -  Information available about  the incident.

      -  Time available to prepare  a  site-specific plan.

      -  Reason for  responding.

      Three general  categories  of response exist - emergencies, character-
      izations and remedial  actions.   Although considerations for personnel
      safety are   generic  and  independent   of the  response  category,  in
      scope, detail, and length  safety  requirements and plans vary consfd-
      erably.  These variations are generally  due  to  the   reason  for
      responding  (or category of response)  ,  information available, and the
      severity of the incident  with  its concomitant.dangers to the respon-
      der.

      A.   Emergencies

          1.  Situation:

              Emergencies  generally   require  prompt  action  to  prevent  or
              reduce undesirable affects.  Immediate hazards of fire, explo-
              sion,  and release  of  toxic  vapors  or  gases are  of  prime
              concern.   Emergencies  vary greatly  in  respect to types  and
              quantities of  material, numbers of responders, type  of work
              required, population affected, and other  factors.   Emergencies
              last from a  few hours to a  few days.

              -   Information available:   Varies from none to much.  Usually
                 information about the chemicals  involved and their associ-
                 ated hazards is quickly obtained in transportation-related
                 incidents,  or incidents involving fixed  facilities.  Deter-
                 mining the  substances  involved in some incidents, such as
                 mysterious  spills,  requires  considerable  time and effort.

              -   Time  available:  Little  time,  generally   requires prompt
                 action to bring the  incident  under control.

              -   Reason for  response:   To  implement  prompt and immediate
                                  9-2
                                  M-5

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                                                                      1/11/85
                                                                New Page M-7
C.  Remedial  Actions

        1.  Situation:
            Remedial  actions are cleanups  which  last over a  long  period
            of time.   They  commence  after more immediate problems at  an
            emergency have been controlled, or they involve the mitigation
            of hazards  and  restoration   of   abandoned   hazardous  waste
            sites.   Numerous activities are required involving many  people
            a logistics and  support  base, extensive equipment, and more
            involved  work  activities.  Remedial actions may require  months
            to years  to completely  accomplish.

            -  Information available:   Much known  about  on-site hazards.

            -  Time available:  Ample  time for  work  planning.

            -  Reason  for  response:    Systematic  and  complete control,
               cleanup, and restoration.

        2.   Effects on Plan:

            Since ample time  is  available  before  work  commences, site
            safety  plan tends  to  be  comprehensive  and  detailed.   From
            prior investigations  much detail  may be  known about the ma-
            terials or hazards at  the  site and extent of  contamination.
IV.  SITE SAFETY  PLAN  DEVELOPMENT

    To develop the plan  as  much background  information  as  possible  should
    be obtained, time permitting, about the incident.  This would  include,
    but not  be limited to:

    -   Incident  location and  name.

  -----   Site  description.

    -   Chemicals and  quantities involved.

    -   Hazards associated with each  chemical.

    -   Behavior  and dispersion of material  involved.
                 •
    -   Types of  containers, storage,  or transportation  methods.

    -   Physical  hazards.

    -   Prevailing weather condition  and forecast.

    -   Surrounding populations and land use.

    -   Ecologically sensitive areas.
                                9-4
                                M-7

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                                                             1/11/35
                                                       New  Paqe  M-9
-  Designate Levels of Protection to be Worn
   The Levels  of  Protection to  be worn  at  locations on-site  or  by
   work functions  must  be  designated.    This  includes the  specific
   types of  respirators and  clothing  to be worn  for  each  level.   No
   one shall  be permitted  in  areas  requiring  personnel  protective
   equipment unless they have been trained in its use and are wearing
   it.

-  Delineate Work Areas

   Work areas  (exclusion   zone,   contamination   reduction  zone,  and
   support zone) need  to  be designated  on  the  site map and  the  map
   posted.  The size  of zones,  zone  boundaries, and  access  control
   points into each  zone  must  be  marked  and  made known to all  site
   workers.

-  List Control Procedures

   Control procedures  must  be  implemented  to  prevent  unauthorized
   access.  Site security  procedures -  fences,  signs,  security  pa-
   trols and check-in  procedures  - must  be  established.   Procedures
   must also be established to  control authorized personnel  into work
   zones where personnel protection is required.

-  Establish Decontamination Procedures

   Decontamination  procedures for personnel  and equipment must be es-
   tablished.  Arrangements must  also be made for the proper disposal
   of contaminated  material, solutions,  and  equipment.

-  Address  Requirements for  an   Environmental   Surveillance  Program

   A program to monitor site hazards must be implemented.   This would
   include air  monitoring  and  sampling, and  other  kinds  of  media
   sampling at  or   around  the  site  that  would  indicate  chemicals
   present, their hazards, possible migration, and  associated safety
   requirements.

-  Specify Any Routine and Special Training  Required

   Personnel must be trained not only  in general safety procedures  and
   use of safety equipment,  but  in any  specialized work they  may  be
   expected te do.

-  Establish Procedures for Weather-Related  Problems

   Weather conditions  can  affect  site  work.  Temperature  extremes,
   high winds, storms,  etc.  impact on personnel  safety.  Work prac-
   tices must be established to  protect  workers from  the effects  of
   weather and  shelters  provided,  when  necessary.  Temperature  ex-
   tremes especially heat  and  its  effect  on people  wearing  protec-
   tive clothing,  must  be  considered and procedures  established  to
   monitor for and  minimize heat  stress.
                             9-6
                            M-9

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                                                                  1/11/85
                                                          New Paae M-ll
     -  Address emergency medical care.
        —  Determine  location  of  nearest  medical  or  emergency  care
            facility.  Determine their capability to handle chemical
            exposure cases.

        --  Arrange  for  treating,  admitting, and transporting  of  injured
            or exposed workers.

        —  Post the medical or emergency care facilities location, travel
            time, directions, and telephone number.

        «  Determine local  physician's office location, travel  directions,
            availability, and post telephone number  if  other medical  care
            is not available.

        --  Determine nearest ambulance service and  post telephone  number.

        —  List responding organization's physicians, safety officers,  or
            toxicologists name and telephone number.  Also include  nearest
            poison control center, if applicable.

        —  Maintain accurate records on any exposure or potential exposure
            of site  workers  during  an  emergency (or  routine  operations).
            The minimum  amount  of   information  needed  (along  with  any
            medical test  results)  for  personnel  exposure records  is  con-
            tained in Annex 8.

     -  Advise workers  of their duties during an emergency.  In  particular,
        it is  imperative that the  site   safety  officers,  standby  rescue
        personnel, decontamination workers, and  emergency medical  techni-
        cians practice emergency  procedures.

     -  Incorporate  into  the  plan,  procedures  for the  decontamination  of
        injured workers and for their transport to medical care facilities.
        Contamination of transport  vehicles, medical  care  facilities,  or
        of medical personnel  may occur  and  should be  addressed   in  the
        plan. Whenever feasible these procedures should  be  discussed  with
        appropriate medical personnel  in  advance of  operations.

     -  Establish procedures in cooperation with local  and state officials
        for evacuating residents  who live near the  site.

                  •
VII. IMPLEMENTATION OF THE SITE SAFETY  PLAN

     The site  safety  plan,   (standard  operating safety procedure  or  a
     generic safety plan for  emergency response) must  be written to avoid
     misinterpretation, ambiguity, and mistakes that verbal  orders  cause.
     The plan must be  reviewed and approved  by qualified personnel.   Once
     the safety plan is implemented, its  needs  to be periodically examined
     and modified, if  necessary,  to  reflect  any  changes in site'-work  and
     conditions.
                                  9-8
                                 M-ll

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 CUSTODY SEAL
 Signature
Exaapl* of EPA Chain-of-Custody S«al
    U.S. Environmental Protection Agency
    Region 5,  Ll^rury (6PL-K-)
    230 S. Dearocrn St'eet, Room 1G70
          ,  1L   60604

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