&EPA
          United States
          Environmental Protection
          Agency
          Office of Emergency and
          Remedial Response
          Washington, DC 20460
EPA/600/K-93/004
May 1993
Seminar on Regional
Considerations for Dense
Nonaqueous Phase
Liquids at Hazardous
Waste Sites:
Implementation and
Enforcement Issues

Presentation Slide
Hardcopy

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                 Disclaimer
Any mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
                                      Printed on Recycled Paper

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                         Table of  Contents
Acronym List
 Dense Nonoqueous Phase Liquid  (DNAPL)
 Site Assessment Study  ...............................  M
   Randall W. Breeder
   Hazardous Site Control Division
   Office of Emergency and Remedial Response

 Ground-Water Remediation Policy Directive and
 Superiund Accelerated Cleanup Model (SACM)  Discussion .........  . 2-1
   Kenneth A. Lovelace, P.E.; P.G.
   Hazardous Site Control Division
   Office of Emergency and  Remedial Response

Technical  Impracticability Project ......................... 3-1
   Peter R. Feldman
   Hazardous Site Control Division
   Office of Emergency and  Remedial  Response

Enforcement Concerns  ............................... 4-1
  Matthew J. Charsky
  CERCLA Enforcement Division
  Office of Waste Programs Enforcement

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                                       Acronym  List
ACL
AM
ARAR
DNAPL
EA
EE/CA
EIS
FS
GW
HSCD
LNAPL
MCL
NCP
NEPA
NPL
OE
OERR
ORD
OSW
OSWER
OWPE
POC
PRP
RD/RA
RED
Rl
ROD
SACM
SAP
SE
SOW
Tl
Alternate Concentration Limits
Action Memorandum
Applicable or Relevant and Appropriate Requirements
Dense Nonaqueous  Phase  Liquids
Environmental Assessments
Engineering Evaluation/Cost Analysis
Environmental Impact Statements
Feasibility Study
Ground Water
Hazardous Site Control Division
Light Nonaqueous Phase Liquids
Maximum Contaminant Levels
National Contingency Plan
National  Environmental Policy Act
National  Priority  List
Office of  Enforcement
Office of  Emergency and Remedial Response
Office of  Research and  Development
Office of Solid Waste
Office of Solid Waste and Emergency Response
Office of Waste Programs Enforcement
Points of Compliance
Potentially Responsible Parties
Remedial Design/Remedial Action
RCRA Enforcement Division
Remedial Investigation
Record of  Decision
Superfund Accelerated Cleanup Model
Sampling and Analysis  Plan
Site Evaluation
Statement of Work
Technical Impracticability
                             A-l

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                   DNAPL  Site  Assessment Study
                                Randall  W. Breeden
                                      Geohydrologist
                               Hazardous Site Control Division
                         Office of Emergency and Remedial Response
                     U.S. Environmental Protection Agency, Washington, DC
Randall  W. Breeden is  a geohydrologist with  the  Hazardous  Site  Control Division of  the Office of
Emergency and  Remedial Response  (Superfund).   He received a  B.S. in soil  science  from  Purdue
University and an M.S.E.S. in water resources from Indiana University.  His technical expertise is in the
assessment of the  design and  operation of CERCLA  and RCRA  ground-water  monitoring systems,
characterization of subsurface hydrostratigraphy, and evaluation of field sampling and analysis programs.
He has been a project manager for all aspects of field  operations for site characterization efforts, and
has performed technical evaluations of more than 40  ground-wafer monitoring and remediation systems.

Prior to joining EPA, Mr, Breeden  was  a vice president and senior  project manager for a major
environmental consulting firm where he provided support to private and public clients for ground-water
remediation projects.
                                           1-1

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       DNAPL Site
   Assessment Study
        Randall W. Breeden
  Office of Emergency and Remedial Response
          Outline
 1. Background
 2. DNAPL Study Approach
 3. Methods of Data Collection
 4. DNAPL Study Results
 5. Conclusions
       Background
Reason for the study:
•Analysis of pump & treat
 technology
•Nineteen Case Study (1989)
• Twenty-Four Case Study (1991)
•Published reports
                             1-2

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                       Background
    Goal of this Study

 Estimate pervasiveness of
 DNAPL contamination in
 subsurface at Superfund
 sites nationwide
                       Background
          Purpose

 Provide technical basis for
 evaluating ground-water
 remediation policy for
 Superfund program
                       Background

Possible Extent of DNAPLs

 • U.S. Solvent Production (in
  pounds):
  a 15 billion— 1986
  n 29 billion — 1990
 • NPL Characterization Database:
  H 85% of Superfund sites have ground-
    water contamination
  • Solvents reported as waste materials at
    66% of sites
                             J.
                                1-3

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                           Background
Possible Extent of DNAPLs
             (Continued)


  • 7 of the top 10 chemicals
   detected in ground water at
   183 hazardous waste sites
   were DNAPL chemicals

             (Plumb and Pitchford, 1985)
     Frequency of Detection of Most Common Organic Contaminants at Hazardous Waste Sites
     (USEPA. tO/tWU and Plumb and Pitchford. 1985).
KAMCCtG BASED
ONNCMBOtOF
SUES AT WHICH
ORGANIC
CO.VTA.MINA.VT
WAS DETECTED
W AW MEDIUM
(VSEM. 1C.17.-JI)
•1
2
3
4
5
6
7
8
9
10
11
12
13
14
IS
16
17
18
19
20
23
40
ORGANIC
CONTAMINANT
Toluene
Trichloroeihenc
Melhylene Chloride
Benzeee
Tetrachloroethene
Ethylbcnzene
1.1.1-Trichtoroethane
Chloroform
Xytenes
bis(2eihyihecyl)
phlhalaie
Acetone
1.1-Dfchtoroeihane
Phenol
trans-1.2-
Dichtoroethene
Napthatene
1,1-Dichloroethene
1.2-Dtchloroethane
Vinyl Chloride
2-Buunone
Chlorobenzenc
Dibutyl Phthalate
Chtorocihanc
DNAPL?
No
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
Yes
No
Yes
No
Yes
Yes
No
No
Yes
Yes
No
FERCEfTACE
OF U«0 SITES
AT 'WHICH
CONTAMINANT
WAS
DETECTED IN
ANY MEDIUM
(USEPA,
1007/91)
6O5
573
54.7
53.2
51.8
47.5
47.1
45.4
443
41.8
40.0
39.7
39.4
38.4
35.5
33.2
32.7
3Z1
31.8
31.4
30.3
18.1
RANKLNG BASED
ON NUMBER OF
STIES AT WHICH
ORGANIC
CONTAMINANT
WAS DETECTED
Df
GHOUNDWATEZ
(FLUME AND
PITCHFORD, 19*5)
2
1
3
7
4
11
9
10
_
6
20
5
14
8
18
13
12
15
_
16
17
19
PERCENTAGE
OF t«3 SITES AT
WHICH
CONTAMINANT
WAS DETECTED
IN
GBODNDWATER
(PLUMB AND
PrTCHFOBD,
19*5)
31.15
34.43
31.15
2732
31.15
25.14
26.78
25.14
_
28.42
12.02
28.42
19.13
2732
1Z57
20.22
21.31
16.39
„
1639
15.30
12.57
                                     1-4

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   DNAPL Study Approach

• Informal surveys indicate DNAPLs
  directly observed at <10% of Superfund
  sites nationwide.
• DNAPLs usually observed accidentally
  and not considered in many
  investigations.
• Study used indirect indicators of DNAPL
  presence from site history and field
  investigations.
                            Approach

   Data Collection Strategy

  • Consistent site information for
   comparative analysis
  • Information from broad spectrum of
   sites, those with high & low DNAPL
   probability
  • Enough detailed information  on
   known DNAPL sites to test
   assumptions regarding indirect
   indicators
                            Approach
   Data Analysis Strategy


  • Develop system to estimate
   DNAPL probability at each
   site.
  • Evaluate the usefulness of
   indirect indicators.
                                     1-5

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                            Approach
    Data Analysis Strategy
              (Continued)
• Evaluate relationship of:
  • site use type
  • site contamination
  • hydrogeological setting

  to the likelihood of DNAPL presence.

• Extrapolate results to entire group of
  Superfund sites.
 Methods of Data Collection


  • Regions Selected: 1, 3, 5, 6,
    and 9
    • Geographic diversity
    • Range of geological settings
    • Range of site uses and
      contaminant types
                                  J
 Methods of Data Collection
              (Continued)


  • Site Selection within Region

   » Remedial investigation complete
      or equivalent amount of site data

   H Organic contamination of ground
      water

   n Site use profile representative of
      region
                                    1-6

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   Hydrogeological Regions   Methods
     of the United States
        Columbia
         Lava Western
           Mountain
           RltlRtS
                        Superior
                        Uplands •.
                            Methods
Number of Sites Evaluated

Region
I
3
5
6
9
# of Sites
Studied
84
162
266
74
126
# of Sites
Evaluated
79 (94%)
92 (57%)
74 (28%)
23 (31%)
42 (33%)
   Total
712
310 (44%)
                            Methods
  Information Collected

 Standardized survey format
  based on EPA Fact Sheet
 • Site History Information
  • Historical site use and industrial or
    waste disposal practices
  • Substances and chemicals on site
    historically
  « Known releases of nonaqueous
    chemicals
                                    1-7

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                             Methods
    Information Collected
 	(Continued)	

 > Site Contamination Information

  • Observations of NAPLs

  • Concentrations of DNAPL-related
    compounds in ground water

  • Patterns of ground-water
    contamination suggesting
    subsurface, nonaqueous source
                             Methods
    Information Collected
              (Continued)


   « Geological Information

     • DeptH to water table

     • Depth to bedrock

     • Detailed descriptions of
      unconsolidated materials and
      bedrock
    DNAPL Study Results

 Ground-Water Contamination Profile
                    # Sites
                   in Regions    # Sites
	1, 3, S,6,&9 Evaluated
No organic contaminants
in ground water
Organic contamination of
ground water with no direct
77
0(0%)
observation of DNAPL
DNAPL observed below
water table
Totals
591
44
712
270 (46%)
40(90%)
310 (44%)
                                     1-8

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          Site Use Profile
                                    Results
 How representative are sites studied?

 Site use In Regions 1, 3, 5, 6,   Site use for sites studied
 and 9
Xof
Sites
X of
Sites
    cat Mut todW If Fed Wood box Met Oh

         Site Use
    Ox Han todw IP Fed WMd bcvxKet Oth

         Site Use
                                    Results
    DNAPL Indications from
             Site History
                             # Sites  % Sites
 Industrial facilities
 associated with use or
 disposal of DNAPLs
 DNAPL-related
 substances and chemicals
 (>5 drums/yr)
 Operations and industrial
 and waste management
 practices with likelihood
 of DNAPL release
        198     64%
       233


       281
75%


90%
           Site History
                (Continued)
                                    Results
                            # Sites   % Sites
 Known releases of               191    62%
 DNAPLs

 Known releases of               124    40%
 DNAPLs in nonaqueous form
                                            1-9

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                             Results
Site History Ranking Method
UkeUhoodof
aubiurfjcc DNAPL:

QHI



i
GHJ




('"LOW"*)
v*— _ — s
•v_


5
4

3
2

1

Known releases or DNAPL
substances or chemicals hi a
nonaqueous form
Combinations of positive
indicators

No known DNAPL-related
practices, substances and
chemicals, or releases
^x

     Site History Ranking
                             Results
A. Known DNAPL Sites (40)  B. Remaining Sites (270)
wun.
Sin
    	ndBUsJL
                             Results
   Summary of Findings from
    Site History Information

  • Ranking system adequately
   predicts high probability of DNAPL
   release for known DNAPL sites

  • Based on site history information,
   about 80% of sites have medium to
   high probability of DNAPL release
                                   1-10

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                               Results
     DNAPL Indications from
        Ground-Water Data	

   Maximum concentrations of DNAPL
   chemicals in ground water
   expressed as percentage of their
   solubilities might be more indicative
   of problem.
     TCE @ 20 mg/l =2% solubility (Sol = 1,000 mg/L)

     PCE @ 20 mg/l = 13% solubility (Sol = 150 mg/L)
    Percentage Solubilities
       Observed for TCE
  # Sites            % Sol   Cone. (ng/L)
                              Results
                         1,000,000
                         500,000

                         100,000

                          30,000

                          10,000
                       MCL
                          1,000
                  0.0005S6
                              Results
DNAPL Chemicals Observed at
 Highest Percentage Solubility


Percent
of
Sites
40
30

20
10
n




nnH
^~






Irun
                Chemical
                                     1-11

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                             Results
    Ranges of Maximum Percent
  Solubilities for DNAPL Chemical in
           Ground Water
M
or
Sites
19
•—
—
Maximum
% Sol # Sites %
Sites
1 11 LI 1 >50% 37 14
X Solubility
•^ ^

     Ground-Water Contamination
         Ranking Method
  Likelihood of
           Results
subuuface DNAPL;
X^VEBTX
V^HIOH.^/
Cjj^yD
i

^MED"^
j
i

(^LovT^

6
5
4
3
2
1

Concentrations of DNAPL chemicals:
50% sol. or
Two @ >25% sol. or
Three @ > 15% sol.

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                             Results
   Summary of Findings from
       Ground-Water Data

 • Most useful indicator is maximum
   percentage solubility of DNAPL
   chemicals detected in ground water.
 • Based on ground-water concentration
   data, ~60% have medium to very high
   probability of DNAPL.
                              Results
   Comparison of Ranking
             Factors
A. Site History Rank
B. Ground-Water
 Contamination Rank
                  Percent 30
                   of
                   SUcs
   Combining the Site History &
 Ground-Water Contamination Ranks
                              Results
Site Hist
Rank
6
5
4
3
2
1
Ground-Water Contam Rank
65432 1
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Hi
Med
Med
Med
Med
Med
Med
Med
Med
Med
Med
Med
Med
Lo
Lo
Lo
Lo
Med
Lo
Lo
Lo
Lo
Lo

                                    1-13

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                                 Results
 Summary of Combined Ranks
Likelihood
of Subsurface
DNAPL
Definite
High
Medium
Low
^
Number
of Sites
40
109
66
95
Percent
of Sites
13%-
3596
21%
31%
_X

                                 Results
 Relationship of Hydrogeological Setting
   to Likelihood of Subsurface DNAPL

A. Site History Rank         B. Ground-Water
                        Contamination Rank
       as* tfxx rmx wcr WAU
                         tfsa ctot tKai not Acer WAU

                           HyiiroieoloiJciI SttflJU
                                 Results
    Relationship of Site Use to
 Likelihood of Subsurface DNAPL
A. Site History Rank
B. Ground-Water
  Contamination Rank
L
f
[-,




[1





nfl
•

ow 6
uk
5
4
3
2
1

1
£j
J-f
   O* Mm MM V PN| v»«4 IM«V KM Otb
                                        1-14

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           Effect of       Results
  Hydrogeological Setting

• No distinguishable difference in
  DNAPL likelihood based on
  geological setting
• Implication: if DNAPLs are suspected
  based on site history, their presence
  should be investigated in all cases,
  regardless of geological setting

                          (Heath)
     Site Use Findings

  • Uses with a higher
    likelihood of subsurface
    DNAPL:
    • Wood treatment
    • Organic chemical production
    • General manufacturing
    • Industrial waste disposal
                            Results
 r,..  TT    T-"   -i-          Results
 Site Use Findings (continued)


 • Uses with a lower likelihood
   of subsurface DNAPL:
   • Combination landfills
   • Primary metals mdustty/mming
   • Inorganic chemical production
                                   1-15

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 f*.  TT    1-"  J-
 Site Use Findings
   > Uses for which site use
    relationship is not clear from
    our study:
    • Federal facilities (high based on
     site history and low based on
     ground water data)
                              Results
Relationship of Contaminant Type to
  Likelihood of Subsurface DNAPL
A. Site History Rank
   tnsr MKmv ojoty FCBOLV t*

       GmUm&uitf Tyyt
B. Ground-Water
  Contamination Rank
                     ireT MXKXV CUOLV KKOLV OfflO OAR OTHER
         Distribution of
       Contaminant Type
                              Results
      Percent
                M.V CUOLV 7CBIQLV OLIO  CTAR

                 Contaminant Type
                                     1-16

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      Summary for Site  Results
     Contaminant Type

• Creosote, Coal Tar, and PCB Sites:
  • Small proportion of sites in Superfund
  • Easily linked with specific site uses
  • High likelihood of subsurface DNAPL
  • Relatively small impact in terms of
   volume of subsurface contaminated
      Summary for Site  Results
 Contaminant Type (continued)

• Chlorinated Solvent & Mixed
  Solvent Sites:
  B Majority of sites in Superfund
  • Associated with wide range of site uses
  • Range in likelihood of subsurface DNAPL
  • Relatively large impact hi terms of
   volume of subsurface contaminated
                             Results
 Average Plume Dimensions
     by Contaminant Type
C      Mixed     N.
     Solvents	/
L = 4,500 ft
W = 1,500 ft
D = 92 ft


L = 2,800 ft
W = 1,000 ft
D = 70 ft
                                    1-17

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                             Results
   Average Plume Dimensions
  by Contaminant Type (continued)
                    L = 1,500 ft
                    W= 1,200 ft
                    D = 26 ft
                    L = 600 ft
                    W = 250ft
                    D = 20 ft
     Regional Distribution  Results
     of DNAPL Probability
  Average
   Rank
                Region
                             Results
    Estimated Scope of the
	DNAPL Problem	
 Extrapolation to 712 NPL sites in Regions 1,
 3, 5, 6, & 9.
 Known DNAPL sites       5% >^
 High (very likely)
 Medium (warrant further
  investigation
 Low DNAPL likelihood
 No organics in ground
  water
35%

20%

30%

10%
40%
                                   1-18

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      Conclusions
• Potential for subsurface DNAPL
 will be consideration at majority
 of Superfund sites.
• May have underestimated
 DNAPL potential because data
 not specific to DNAPLs.
  Conclusions
(Continued)
> Future research efforts should
 focus on chlorinated solvent
 and mixed solvent sites, as
 these constitute the majority of
 Superfund sites and present the
 greatest challenge with respect
 to site characterization and
 remediation.
                                1-19

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       Ground-Water  Remediation  Policy Directive  and
Superfund Accelerated  Cleanup Model (SACM)  Discussion
                               Kenneth  A. Lovelace
                                 Environmental Engineer
                              Hazardous Site Control Division
                         Office of Emergency and Remedial Response
                      U.S. Environmental Protection Agency, Washington, DC
    Kenneth A. Lovelace is an environmental engineer with Superfund's Hazardous Site Control Division.
    He received a B.S. in geology from the University of California, Davis, and an M.S. in civil engineering
    from Colorado State University.

    Mr. Lovelace has more than  14 years of professional experience in hydrology, as a consultant and as
    a senior engineer for an oil pipeline company. His primary area of responsibility at EPA is developing
    national policy  for characterization, cleanup, and  management of ground-water contamination at
    hazardous waste sites.
                                        2-1

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        Ground-Water
     Remediation Policy
     Directive and SACM
         Discussion
      Kenneth A. Lovelace, P.E., P.G.
  Office of Emergency and Remedial Response
Ground-Water Remediation
      Policy Directive

 • Background
 • Site Investigation
 • DNAPL Characterization
 • Early Actions
 • Remedy Design
 	Background	

 > Ground-water contamination is
 present at:
 • 85% of Superfund National Priority
   List (NPL) sites
 • 50% of permitted RCRA land
   disposal fatalities
                               2-2

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     Background
(Continued)
  > Subsurface NAPLs, especially
   DNAPLs, will significantly
   impact ground-water
   remediation
   • Are long-term sources of
    contaminants
   • Control of sources needed to
    achieve cleanup standards
     Background
(Continued)
  • OSWER Policy Directive, May 27,
   1992
  • "Considerations in Ground-Water
   Remediation at Superfund Sites
   and RCRA Facilities - Update"
  • Affects CERCLA Remedial Action,
   RCRA Corrective Action
     Site Investigation

• Evaluate likelihood of NAPL
 occurrence early
  • Use DNAPL fact sheet
  • Historical and existing field data
  • During pre-remedial work, if possible
  • Needed for planning site
   investigation
                                  2-3

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 Site Investigation
(Continued)
 •If NAPLs likely, further
   characterization should:
   • Suggest areas where LNAPLs or
    DNAPLs might be present
   • Confirm NAPL presence
   • Estimate NAPL extent, to extent
    possible
 Site Investigation
(Continued)
 •Why is characterization
   needed?
   • Define sources of contaminants
   • Estimate flow paths and
    travel time
   • Identify possible remedial
    strategies
DNAPL Characterization

• Locate geologic DNAPL traps
  • Topographic valleys in bedrock
   surface
  • Traps formed by geologic features
• Focus efforts on DNAPL
  accumulations
  • More likely to be found
  • Depends on site conditions,
   exploration methods
                                 2-4

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DNAPL Characterization
           (Continued)

  • Locating DNAPL in small
   discontinuities is very
   difficult
  • Caution should be exercised
  • Can be combined with other
   investigation efforts
      Early Actions

 > Actions initiated before remedial
  investigation (RI) is completed.
  Removal or remedial actions.
 > Focus of early actions is to:
  • Reduce site risks
  • Prevent exposure to contaminants
  • Minimize further migration
  • Control sources
   Early Actions
(Continued)
 Directive recommends
 • Early plume containment
 • Early extraction of free-
   phase NAPLs
                               2-5

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    Early Actions
(Continued)
•Why are these actions
  important?
  • Protect surrounding aquifer
  • Protect wells or ecological resources
  • Free-phase is mobile fraction and is
   extractable
  •Much more effective to remove NAPL
   sources
      Remedy Design

   • Actions should be
    implemented in a phased
    approach
   • Information gained from
    earlier phases is used to
    refine later phases (also
    "smart approach")
  Remedy Design
 (Continued)
 • Why is phased approach useful?
  • Integrates data collection with site
    conceptual model
  • Integrates investigation and remedial
    activities
  • Integrates early actions with, long-term
    actions
  • Provides flexibility to respond to new
    information
  • Minimizes uncertainty between phases
                                   2-6

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 Remedy Design
 • Design should include
  monitoring to:
  • Determine effectiveness of action
  • Suggest remedy improvements
  • Refine predicted cleanup time
 Remedy Design
(Continued)
 • Design should allow for
  modification of remedy after
  implementation to:
  • Improve effectiveness
  • Reduce remediation time
  • Respond to new information
      Ground-Water
Remediation and SACM
 • Key SACM elements
 • Long-term actions
 • Early actions
 • SACM and Policy Directive
 • Remedial/removal actions
                              2-7

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   Key SACM Elements


 • Superfund Accelerated Cleanup
  Model (SACM)

 • Regional Decision Team used to:
  • Integrate investigation, and assessment
    activities
  • Coordinate Superfund program elements
  • Coordinate early state and community
    involvement
   Key SACM Elements
	(Continued)	

 • Combine early and long-term actions

 Time Frame      Site Response
 Under 5 years +/-  Early actions to expediently
              reduce site risks. Integration
              of early actions, with site
              investigation.
 Over 5 years +/-
Long-term actions for longer
or more complex remediation,
such as environmental
restoration.
    Long-Term Actions


  •Types of action:

    •Restoration to cleanup
      levels

    •Complex source control
    •Maintaining plume and/or
      source containment
    •Monitoring
                                  ,2-8

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        Early Actions
 • Types of action:
   • Preventing exposure to
    contaminants
   • Preventing further migration
   • Controlling sources - soils, NAPLs
   • Field testing of restoration
    technologies
 SACM and Policy Directive
 • Use of early actions is a key
  recommendation of Policy
  Directive.
 • Integration of early and long-term
  actions follows "phased approach"
  recommended.
 • Early actions include CERCLA
  remedial or removal actions.
Remedial/Removal Actions
• Remedial actions
  • Sites must be on National Priorities
   List (NPL)
  • No statutory time or cost limitation
  • Early actions are generally interim
   actions
  • ARARs must be met or waived
  • Fund/state cost share required
                                  2-9

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   Remedial/Removal Actions
               (Continued)
  > Removal actions
   • Sites can be pre-NPL or NPL
   • Three types: emergency, time critical,
    non-time critical
   • limited to 12 months and $2 million,
    some exemptions
   • ARARs must be met to extent practicable
    or waived
   • Fund/state cost share not required, but
    recommended
 Remedial/Removal Actions
               (Continued)
Removal


(Removal) Site Evaluation
  (SE)
Sampling and Analysis
  Plan (SAP)*
Engineering
  Evaluation/Cost
  Analysis (EE/CA)*
Action Memorandum (AM)
Remedial Investigation
  (Rl)
Sampling and Analysis
  Plan (SAP)
Feasibility Study (FS)
Record of Decision (ROD)
" Non-Mine critical removals only.
                                        2-10

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                Technical  Impracticability  Project
                                 Peter R. Feldman
                                  Environmental Scientist
                              Hazardous Site Control Division
                         Office of Emergency and Remedial Response
                    U.S. Environmental Protection Agency, Washington, DC
Peter  R. Feldman is an environmental scientist  in Superfund's Hazardous Site Control Division.  Mr.
Feldman received a B.A.  in geology from Wesleyan  University and an M.S. in hydrology from the
University of Arizona.

Prior to joining EPA in 1991, Mr. Feldman worked in the consulting field on environmental impact and
engineering studies, water-supply development projects, and hazardous waste investigations. His current
responsibilities at EPA include development of policy and guidance related to ground-water remediation
for the Superfund program in addition to site-specific consultations at various NPL sites.
                                           3-1

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       Technical
   Impracticability
         Project

         Peter R. Feldman
 Office of Emergency and Remedial Response
Purpose and Overview

 • Background and goals
 • Technology limitations and
  role of XI
 • Specifics of draft guidance
 • Discuss issues; get feedback
      Background

 > Technical studies
  »19 and 24 site studies
  • Ongoing research on pump &
   treat
  • DNAPL site survey
                             3-2

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     Background
(Continued)
 Use of TI waivers discussed in:
 • NCP, NCP preamble
 • 1988 OERR ground-water guidance
 • 1989 Cannon ground-water remediation
  memo
 • 1990 OERR/OWPE ROD language memo
 • 1992 Clay ground-water remediation
  memo
      NCP Expectation for
     Ground-Water Cleanup

 "... EPA expects to return usable
 ground waters to their beneficial
 uses wherever practicable,
 within a timeframe that is
 reasonable given the particular
 circumstances of the site."
                     §300.430(aXD(iii)(F)
 CERCLA ARAR Waivers

• Interim action
• Greater risk
• Technical impracticability
• Equivalent standard of performance
• Inconsistent state application
• Fund balancing
                  (See CERCLA 121(d)(4)(c))
                                  3-3

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   Existing Guidance on TI

 NCP criteria:

 "— engineering feasibility and
   reliability, with cost generally
   not a major factor unless
   compliance would be
   inordinately costly."
  Definition of "Impracticable"

 Impracticable: incapable of being
  performed or accomplished by the
  means employed or at command.

 Impractical: not wise to put into or
  keep in practice or effect; not
  pleasing to common sense or
  prudence.
            (bom Webster's 3rd International Dictionary, 1971)
  Existing Guidance
(Continued)
On "reasonable time frame":

NCP Preamble: Very rapid (1 to 5
years) to extended (several
decades)

OERR Guidance (1988): "Less than
100 years"
                                  3-4

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  Existing Guidance
(Continued)
 On "engineering feasibility," 1988
  Guidance considers:
 • Widespread plumes/unidentified
  sources
 • Hydrogeologic constraints (e.g.,
  fractured rock, karst, low permeability)
 • Contaminant characteristics (e.g.,
  DNAPLs)
 • Sorption/desorption kinetics
    Past Use of TI Waivers

• Waiver in ROD
  • Used 13 times
• Contingency TI waiver in ROD
  • Used 24 times
• Post-ROD waivers/contingencies
  • 3 cases
      Use of TI Waivers
           (through 1992)
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                                    3-5

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      Reasons for TI
   DNAPLs

   Extent of
Contamination

    Karst

   LNAPLs

 ARAR Lower
  ThanPQJ.
              Ntunber of RODs
  Status of TI Guidance

   • Draft stage only
   • Regional/state review
    Summer '93
   • Followed by EPA senior
    management review, final
    revisions
     Goals of Guidance

 • Consistency across regions
   and programs
 •Address growing volume of
   H decisions
 • Clarify decision criteria and
   data requirements
                                3-6

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 Goals of Guidance
(Continued)
• Encourage better site
 characterization and remedy
 performance monitoring
• Clarify legal and
 administrative issues
• Develop approach for
 selecting alternative remedial
 strategies
 Ground-Water Remedy
  Decision Framework
    Uncertainty in GW
    Remedy Decisions

   • Remediation outcome
    difficult to predict
   • NCP provides flexibility
    needed to reduce
    uncertainty
                              3-7

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   Uncertainty in GW Remedy
	Decisions (Continued)	
 Can resolve uncertainty through:
 • Thorough site characterization (NAPLs)
 • Phased approach to characterization
  and remediation
 • Early and interim actions (SACM)
 • Monitor and analyze data
 • Base final cleanup decisions on more
  complete knowledge
  Uncertainty and Decision
_ Documents _
Available Options:
Little to no r\ ARAR-Compliant ROD or
uncertainty L/ Tl Waiver in ROD
Moderate  r\ Contingent TI waiver
uncertainty |_/ in ARAR-Compliant ROD
High
uncertainty
             Interim Action ROD
             (no ARARs, or interim
             action waiver)
        Approach for
        Evaluating TI
                                   3-8

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  71 ^Waiver AppCication

  Site	needs a TI waiver
  because:

D It will be REALLY REALLY
  expensive to clean it up, or

D It will take a REALLY long
  time to clean it up
                            ~\
     Demonstrating TI:
    Factors to Consider

1. Adequacy of site conceptual
  model
2. Hydrogeologic constraints
3. Contamination-related
  constraints
4. Degree and effectiveness of
  source control
     Demonstrating TI:
 Factors to Consider (continued)
 5. Remedial action performance
  appraisal
 6. Applicability of other
  technologies
 7. Predictions of restoration
  timeframes
 8. Cost estimate
                              3-9

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 1. Site Conceptual Model

Develop using iterative approach
• Contaminant sources, properties,
 distribution
• Geology and hydrology
• Assumptions and hypotheses
 regarding transport, fate,
 remediation
 Examples of Activities
   Providing Data for
  Model Development
                             3-10

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     Site  Conceptual Model
           Development
 > Site background
 and history
 • PreUininary site
 investigations
   Identify
  Sources and
   Receptors
                          9 Model used to
                           scope detailed site
                           investigation
    Site Conceptual Model
         Development
• Early action/
 removal
• Site
 characterization
 (RI/FS, RFI, etc.)
• Removal of
 subsurface
 sources
  DNAPL
 Removal
 Drum
Removal
          Excavation and
            Capping
                 Monitoring
                       • Model used to design
                        pilot studies and
                        subsurface actions
                  3-11

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   Site Conceptual Model
        Development
•Pilot
  studies
•Interim
  actions
A
-/
Pilot
Studies
                 Interim Action
                  Hydraulic
                  Containment
                   Model used to:
                   • Evaluate potential for
                    restoration (or TI)
                   • Develop treatment tram
                    concept/design
   Site Conceptual Model
         Development
•Full-scale
 treatment
•Performance
 monitoring
 and
 evaluations
          • Continued
           enhancement of
           conceptual model
          • Enhancement or
           augmentation of
           remediation system,
           if required
          9 Further evaluation of
           restoration potential
           (or TI), if required
                 3-12

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      2. Hydrogeologic
         Constraints
  Examples
  •Heterogeneity
  •Hydraulic conductivity
  •Fracturing/solution features
  •Depth
   3. Contaminant-Related
        Constraints

• Phase (i.e., aqueous, nonaqueous)
• Distribution
• Physical properties (e.g., viscosity,
 density)
• Transport and fate (e.g., retardation,
 biodegradability)
      4. Source Control

  • Includes residual and free-
    phase NAPLs
  • Removal, stabilization,
    isolation
  • Monitoring to assess
    effectiveness
                                3-13

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  5. Remedy Performance
	Appraisal	
 • Suitability of technology or
  design
 •Adequacy of monitoring
 • Operational history;
  enhancements
 • Trends in ground-water
  concentration
  Trends in Ground-Water
	Concentration	
 • Aqueous plume
  contained/reduced?
 • Rate of concentration decline?
 • Dilution or natural attenuation
  responsible?
 • Rebound during shutdown?
  6. Applicability of Other
        Technologies

  • Use of innovative
   technologies encouraged by
   statute
  • Burden on PRP to
   demonstrate none applicable
                              3-14

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 7. Restoration Timeframes

»Not explicit TI decision criterion
> Predicted through modeling -
 inherent uncertainty
> Deemphasize threshold value for
 "reasonable" timeframe
> Useful for alternatives comparison
 or to indicate possible constraints
           8. Cost


• Subordinate to protectiveness
• Legitimate consideration in
  "engineering feasibility"
• ARARs may not be subject to
  cost/benefit analysis
   TI Evaluation Tools

 • Literature
 • Treatability studies and pilot
  systems
 • Modeling
 • Remedy performance
  appraisals
                               3-15

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 TI Evaluation Tools
(Continued)
 Other factors to consider
 • Accurate evaluation might
  require installation of system
 • Restoration potential might
  vary across site
 • Use of treatment trains might
  be necessary
      TI Review Process
  • Decisions made by Regional
   Administrator
  •HQ. consultation at Division
   Director level
  • Regional or ORD technical
   support role critical
    Possible Outcomes of
	Review Process	

• Decision, package inadequate
• Install/enhance system to reach ARARs
• Install/enhance system to reach non-
  ARAR standard
• Maintain existing system to reach non-
  ARAR standard
• Use source control, institutional
  controls, natural attenuation
                                  3-16

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    Alternative Remedial
           Strategies

    NCP expectations
    • Prevent further migration
    • Prevent exposure
    • Evaluate further risk
     reduction
     Alternative Remedy
	Selection
 • Nine criteria analysis of
  alternatives
 Also consider:
 • Current and future use
 • Likelihood of exposure
 • Availability of alternate supplies
   Alternative Remedial
          Strategies _
 Suggested Approach
       1- Less strmgent ARAR
       2. Waive portion of site only
       3. Site-specific cleanup levels
       4. Remediate to extent
        practicable; focus on source
        control, containment, and
        exposure control
 preferable
                                3-17

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       CERCLA ACLs
 Alternate Concentration Limits can
   be used where:
 • Contaminated ground-water
   discharges to surface water
 • No statistically significant
   concentration increase
 • Can prevent exposure to
   contaminated ground water
    NCP Policy on ACLs

• ACLs not an entitlement, but a
 limitation on use of higher
 limits
• Remediation to ARARs must
 also be impracticable (nine
 criteria analysis)
• Where ACLs used, TI waivers
 not necessary
	Summary	
»Reduce uncertainty through
 phased approach
(Emphasize source control
»Detailed site characterization
 and performance monitoring
 needed
                                3-18

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      Summary
(Continued)
• TI Waivers used only where
 justified on engineering basis
• Distinguish between poorly
 designed systems and real
 problems
• Alternative remedial strategy
 must be established
     Summary
(Continued)
   • Assess protectiveness and
    reliability
   • Take further action if
    warranted
                               3-19

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                           Enforcement  Concerns
                                 Matthew  J. Charsky
                                          Geologist
                                 CERCLA Enforcement Division
                            Office of Waste Programs Enforcement
                     US. Environmental Protection Agency, Washington, DC
Matthew J. Charsky is a geologist in the Office of Waste Programs Enforcement.  Mr. Charsky was
responsible for the Oversight Guidance on PRP RI/FS which was issued in 1991 and for conducting the
regional training to  promote this  guidance.   He currently is completing a risk assessment evaluation
to determine who will conduct future Superfund risk assessments.  Mr. Charsky also has participated
as the  enforcement representative  on numerous work groups and reviewed many guidance documents
associated with ground-water and treatment technologies, particularly on technical impracticability, multi-
source  ground water, and available and potential treatment technologies for  ground water.

Prior to joining EPA, Mr. Charsky worked  at the  Federal Energy  Regulatory Commission where he
developed and reviewed Environmental Impact Statements (EISs) and Environmental Assessments (EAs)
under the National  Environmental Policy  Act (NEPA) for natural-gas pipeline construction  projects
nationwide.
                                           4-1

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     Enforcement
        Concerns
        Matthew J. Charsky
   Office of Waste Programs Enforcement
         Contacts

      Matt Charsky, OWPE
   CERCLA Enforcement Division
         (703) 603-8931

      Trish Gowland, OWPE
   CERCIA Enforcement Division
         (703) 603-8975

       Kurt Lamber, OWPE
   CERCIA Enforcement Division
         (703) 603-8986
        Overview


1. Program Consistency
2. Categories of Uncertainty
3. Available Options
4. What's Important
5. Current Technologies
                               4-2

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      Communication
  Program Consistency

  I. Superfund Delegation on
    TI Waivers for DNAPLs
  2. Fund vs. Enforcement-
    Lead
  3. Superfund vs. RCRA
  4. OSWER vs. OE
  Superfund Delegation

•Proposed remedies for sites
 warranting consultation concerning
 TI waivers for DNAPLs in ground
 water and soil is delegated at the
 Division Director's level in
 Headquarters
      (Twenty-fourth Remedy Delegation Report -
      FY 1993, February 18, 1993)
                              4-3

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 Fund vs. Enforcement-Lead

• More enforcement-lead known or
 suspected DNAPL sites than fund-lead
• More enforcement-lead RODs with
 contingency language for TI than
 fund-lead
• Perception that ARAR waiver for TI
 gives a "greater advantage" to PRPs
   Superfund vs. RCRA


    1. Proposed Subpart S
    2. Current Projects
    3. Contacts
     RCRA Framework

 The proposed RCRA Corrective
 Action Rule "Subpart S"
   Corrective Action for Solid Waste
   Management Units (SWMUs) at
   hazardous waste management
   facilities; (proposed Subpart S
   Rule 40 CFR 264.540, (a) and (b))
   [FR July 27,1990, Volume 55,
   Number 145]
                                 4-4

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  RCRA Framework
(Continued)
   • Currently used as guidance
   • Provides only the published
    discussion of TI in the RCRA
    program
   Current Status of RCRA
	Program

 RED &  Working on TI (technical and
 OSW    process issues) via OERR
        work group and RCRA
        subgroup
 OSW    Drafting a policy strategy for
        Tluse

        Planned completion: FY93
          Contacts	

          Rose Lew, OWPE
      RCRA Enforcement Division
          (202) 260-6720

        Guy Tomassoni, OSW
   Permits & State Programs Division
          (703) 308-8622

       Dave Bartenfelder, OSW
   Permits & State Programs Division
          (703) 308-8629
                                 4-5

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   Consent Decree Language
    Addressing TI Waivers

 Provide guidance regarding the use
 of TI language in Remedial
 Design/Remedial Action (RD/RA)
• consent decrees and statements of
 work (SOWs) involving remediation
 of ground water.
      Focused Purpose

  Address situations where well-
  designed ground-water extraction
  systems might not be able to
  reduce the levels of one or more
  contaminants to the required
  performance standards hi a
  timeframe that EPA deems
  reasonable given the particular
  circumstances of the site.
        Current Draft -
       Dated August 1992

 Current Status
 • Sample language, not model
  language
 • No official inference
 • Regional/HQ. staff input in order to
  achieve all inclusive language
 • Work group presently disbanded
                                  4-6

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        Current Draft -
   Dated August 1992 (continued)

     • Outstanding issues:
      • Technical requirements
      • Judicial review
          Contact:
        Mary Andrews
      Attorney - Advisor
     Office of Enforcement
        (202) 260-3109
    Relating Timeframe of
Identified/Suspected DNAPL to
   Categories of Uncertainty

  1. During Negotiations
  2. During Site Characterization
  3. At Decision Document Stage
  4. Performance Data
                               4-7

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   Available Options for
DNAPLs at Superfund Sites

 1. Waive ARAR Due to TI in
   ROD
   • State standard
   • Chemical-specific standard
   • Entire/portion of aquifer
 Available Options (continued)

2. Contingency Language for TI
  in ROD
  €> Aim for remediation
  « Back off to another level of
    protection
  « No waiver of ARARs
  €» Delay waiver to later stage
    (i.e., RD/RA)
  Available Options (continued)

 3. Interim Actions
   4» Issue removal order to
    contain as interim remedy
   * Gather additional data
    outside area of containment
                               4-8

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     What's Important?

 • Build defensible data package
 • Contact available resources
 • Verify remedy performance
  data
 • Justify which MCLs are
  unachievable and the basis for
  other standards
  Current Technologies

• Current technologies might be able
  to contain DNAPL sources
• Current technologies might be able
  to remediate DNAPL in the aqueous
  phase
• Need to promote development of
  innovative technologies to do a
  better job than current
  technologies
 	Summary

 > The Enforcement Program's
  DNAPL policy is evolving.
 > The Enforcement Program
  favors a cautious and
  conservative approach when
  DNAPLs are known or
  suspected.
                               4-9

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    Summary
  Tlie Enforcement Program
  aims to set achievable
  DNAPL goals and, when
  appropriate, justify the
  need for an ARAR waiver
  due to XL
Conservative Approach
                             4-10
                                    j.S.GOVERNMENT PRINTING OFFICE: i 1993 - 750-063/60010

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