Hazard Ranking System Issue Analysis:
Options for Revising the Air Pathway
MITRE
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Hazard Ranking System Issue Analysis:
Options for Revising the Air Pathway
Thomas F. Wolfinger
August 1987
MTR-86W53
SPONSOR:
U.S. Environmental Protection Agency
CONTRACT NO.:
EPA-68-01-7054
The MITRE Corporation
Civil Systems Division
7525 Colshire Drive
McLean, Virginia 22102-3481
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Department Approval:
MITRE Project Approval:
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ABSTKACT
This report presents two options for revising the air pathway
of the EPA Hazard Ranking System (HRS). The HRS is used by EPA to
rank uncontrolled wastes sites based on their relative threat to
human health and the environment. Highly ranked sites are placed on
the National Priorities List for further investigation and possible
remedial action. The options focus on the incorporation of a
"potential-to-release" option within the HRS air pathway. Inclusion
of such an option would make the air pathway consistent with the
other HRS migration pathways. The options also include recommended
changes to other components of the air pathway to increase the
ability of the HRS to discriminate the threat between sites. These
changes arise from an analysis of weaknesses in the HRS and advances
in the science of air emissions from hazardous wastes sites.
Suggested Keywords: Superfund, Hazard ranking, Hazardous waste, Air
emissions.
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TABLE OF CONTENTS
Page
LIST OF ILLUSTRATIONS vii
LIST OF TABLES viil
1.0 INTRODUCTION 1
I.I Background 1
1.2 Issue Description 3
1.3 Organization of Report 5
2.0 OVERVIEW OF AIR POLLUTION FROM HAZARDOUS WASTES SITES 7
2.1 Emission Processes 7
2.2 Factors Determining Emission Rates and Duration 9
2.3 Contaminant Transport and Transformation 13
3.0 ISSUES IN THE HRS AIR PATHWAY 19
3.1 Background on the Hazard Ranking System 19
3.2 Issues in the Current HRS Air Pathway 22
3.3 Options for Revising the HRS Air Pathway 30
4.0 MULTIPLE SOURCE, PROBABILISTIC APPROACHES 31
(OPTIONS 1 AND 1A)
4.1 Release Category 33
4.1.1 Observed Release 34
4.1.2 Potential to Release 41
4.2 Waste Characteristics Category 78
4.3 Targets Category 81
4.4 The Overall Pathway Score 86
5.0 SINGLE, "WORST" SOURCE APPROACH (OPTION 2) 89
5.1 The Option 2 Potential to Release Evaluation Mechanism 90
5.1.1 Emission Source Descriptors 93
5.1.2 Contaminant Mobility 97
5.1.3 Containment 99
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TABLE OF CONTENTS (Concluded)
Page
6.0 IMPLICATIONS 105
6.1 Improvements in the HRS and the NPL 105
6.2 Cost Implications 107
6.3 Potential Implications for Other HRS Pathways 109
7.0 SUMMARY AND CONCLUSIONS 111
8.0 REFERENCES AND BIBLIOGRAPHY 113
8.1 Selected References on Emission Processes 113
8.2 Selected References Addressing Air Monitoring Guidance 114
8.3 Principal References Used in Developing Containment 115
Factors
8.4 General Bibliography 116
APPENDIX A - SUMMARY OF AIR MONITORING DATA AT SELECTED 141
WASTES SITES
APPENDIX B - DISCUSSION OF REJECTED OPTIONS 147
APPENDIX C - STEP-BY-STEP INSTRUCTIONS AND EXAMPLES 181
APPENDIX D - ADDITIONAL TABLES 229
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LIST OF ILLUSTRATIONS
Figure Number Page
1 Basic HRS Structure 23
2 Map of PE Index for State Climatic Divisions 70
vii
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LIST OF TABLES
Table Number
1 Ambient Air Monitoring Results for Selected 10
Wastes Sites
2 Atmospheric Residence Times for Selected 16
Contaminants Detected at Hazardous Wastes
Sites
3 Ranges of Estimated Levels of Organic Vapors 17
in Ambient Air of Household Basements in
Niagara Falls, NY
4 HRS Scoring Factors 21
5 Overview of Important Features of Air 32
Pathway Options 1 and LA
6 Site Conditions That Make It Difficult to 40
Demonstrate an Observed Release
7 Time Needed for 75 Percent of Selected Compounds 44
to Volatilize for Various Disposal Methods
8 Data on Mobility of Phenol and Dichloroethylene 46
9 Option 1 Emission Source Descriptors 50
10 Option 1A Emission Source Descriptors 52
11 Option 1 Size Ranges 55
12 Option LA Size Ranges 57
13 Option 1 Emission Source Descriptors and Values 60
14 Option 1A Emission Source Descriptors and Values 62
15 Gas Mobility Values 64
16 Method for Evaluating Gas Mobility 66
17 Alternate Metnod for Assigning Particulate 71
Mobility Factor Values
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LIST OF TABLES (Concluded)
Table Number Page
18 Combined Mobility Factor Matrix 73
19 Examples of Containment Factors and Values 75
20 Combined Containment Factor Matrix 76
21 Method of Calculating Overall Site Release 79
Value
22 Combined Toxicity-Mobility Factor Matrix 82
23 Current HRS Target Population Factor Matrix 84
24 Method of Calculating Air Pathway Score 87
25 Illustration of Option 2 Potential to Release 92
Evaluation Procedure
26 Option 2 Emission Source Descriptors and 94
Definitions
27 Option 2 Minimum Size Requirements 95
28 Option 2 Emission Source Descriptor Values 96
29 Option 2 Particulate Mobility Factor 98
30 Option 2 Particulate Containment Factors 100
31 Option 2 Gas Containment Factors 102
32 HRS Scoring Distribution for "Marginal" Sites 108
Lacking Observed Air Releases
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1.0 INTRODUCTION
1.1 Background
The Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA) (PL 96-510) requires the President to
identify national priorities for remedial action among releases or
threatened releases of hazardous substances. These releases are to
be identified based on criteria promulgated in the National
Contingency Plan (NCP). On July 16, 1982, EPA promulgated the
Hazard Ranking System (HRS) as Appendix A to the NCP (40 CFR 300;
47 FR 31180). The HRS comprises the criteria required under CERCLA
and is used by EPA to estimate the relative potential hazard posed
by releases or threatened releases of hazardous substances.
The HRS is a means for applying uniform technical judgment
regarding the potential hazards presented by a release relative to
other releases. The HRS is used in identifying releases as national
priorities for further investigation and possible remedial action by
assigning numerical values (according to prescribed guidelines) to
factors that characterize the potential of any given release to
cause harm. The values are manipulated mathematically to yield a
single score that is designed to indicate the potential hazard posed
by each release relative to other releases. This score is one of
the criteria used by EPA in determining whether the release should
be placed on the National Priorities List (NPL).
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During the original NCP rulemaking process and the subsequent
application of the HRS to specific releases, a number of technical
issues have been raised regarding the HRS. These issues concern the
desire for modifications to the HRS to further improve its
capability to estimate the relative potential hazard of releases.
The issues include:
• Review of other existing ranking systems suitable for
ranking hazardous waste sites for the NPL.
• Feasibility of considering ground water flow direction and
distance, as well as defining "aquifer of concern," in
determining potentially affected targets.
• Development of a human food chain exposure evaluation
methodology.
• Development of a potential for air release factor category
in the HRS air pathway.
• Review of the adequacy of the target distance specified in
the air pathway.
• Feasibility of considering the accumulation of hazardous
substances in indoor environments.
• Feasibility of developing factors to account for
environmental attenuation of hazardous substances in ground
and surface water.
• Feasibility of developing a more discriminating toxicity
factor.
• Refinement of the definition of "significance" as it relates
to observed releases.
• Suitability of the current HRS default value for an unknown
waste quantity.
• Feasibility of determining and using hazardous substance
concentration data.
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• Feasibility of evaluating waste quantity on a hazardous
constituent basis.
• Review of the adequacy of the target distance specified in
the surface water pathway.
• Development of a sensitive environment evaluation
methodology.
• Feasibility of revising the containment factors to increase
discrimination among facilities.
• Review of the potential for future changes in laboratory
detection limits to affect the types of sites considered for
the NPL.
Each technical issue is the subject of one or more separate but
related reports. These reports, although providing background,
analysis, conclusions and recommendations regarding the technical
issue, will not directly affect the HRS. Rather, these reports will
be used by an EPA working group that will assess and integrate the
results and prepare recommendations to EPA management regarding
future changes to the HRS. Any changes will then be proposed in
Federal notice and comment rulemaking as formal changes to the NCP.
The following section describes the specific issue that is the
subject of this report.
1.2 Issue Description
Several issues relevant to the HRS air pathway have been raised
by Congress and by public comments on the NPL and NPL rulemaking
actions. Some of these issues have been the subject of discussions
in Congress as it debates extending and revising CERCLA. Because of
these comments and discussions, EPA has decided to re-examine the
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desirability and feasibility of including an option within the air
pathway release category that would allow sites lacking data
documenting a release of contaminants into the air, to be scored
based on their "potential to release". Currently, the air pathway
is scored only when a release of air contaminants into the atmosphere
can be documented. The inclusion of such an option would make the
structure of the air pathway consistent with both the ground water
and surface water pathways.
The principal purpose of this report is to define alternate
mechanisms for scoring sites for the air pathway. The principal
emphasis is on modifications to allow sites to be scored based on
their potential to release CERCLA contaminants into the air, in the
absence of observed releases. The approach embodied in the options
is different from that used in the other HRS migration pathways.
The approach is based on the use of subjective probability to assess
the potential of a site to release a significant quantity of
contaminant as indicated by selected physical characteristics of the
site. Additional modifications were investigated that arose either
as logical extensions of the potential to release modifications or
from perceived weak points in the HRS as discussed by commenters.
Overall, the intent is to provide options that would generally
improve the degree to which the HRS reflects the potential threat
from uncontrolled waste sites. This report also addresses the
additional costs that would be associated with the incorporation of
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such a mechanism in the HRS. Additionally, the report addresses
limited testing of the options for validity, feasibility and
completeness.
The report presents the options and supporting documentation to
EPA to assist the Agency in determining if and how it would modify
the air route of the HRS.
1.3 Organization of Report
The body of the report is organized in six main sections with
accompanying appendices. Section 2 presents an overview of the
phenomena of air pollution from waste sites. Section 3 presents an
overview of the HRS and discusses the principal air pathway issues
addressed by the options. Section 4 discusses two multiple source,
probabilistic approaches to evaluating potential to release, as well
as other proposed revisions to the air pathway. The options
discussed in this chapter constitute alternate air pathways. A
simple, single-source potential to release option is discussed in
Section 5. Section 6 discusses the implications for the HRS and NPL
as well as program costs that might arise if the revision options
are adopted. Section 7 presents a summary of the options and
recommendations on revising the HRS air pathway.
Appendix A presents summaries of the limited data available
on air contaminant emissions from waste sites. A discussion of
revision options that were rejected during the study is presented
in Appendix B. Appendix C presents step-by-step instructions for
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employing the most complex option (Option 1), as well as an example
of its application to a hypothetical site. This appendix also
contains an example of the application of the simpler option
(Option 2) to the same site. Appendix D contains definitions of the
basic emission source descriptors used in the options, as well as
detailed containment factor descriptors for Options 1 and 1A.
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2.0 OVERVIEW OF AIR POLLUTION FROM HAZARDOUS WASTES SITES
A review of the processes that could result in the release of
air contaminants from waste disposal sites leads to the conclusion
that nearly all disposal facilities either currently emit, have
emitted, or will emit air pollutants. The exceptions are those
sites whose containment is such that it forms (and will continue to
form) an impermeable barrier between the contaminants and the
atmosphere. Whether the pollutants are emitted in sufficient
concentration to merit concern, or even be detected, depends on
numerous site-specific factors.
The following discussion presents an overview of current
knowledge about emissions from uncontrolled hazardous wastes sites.
The discussion is intended to provide background information
pertaining to the options presented in Sections 4 and 5. A list of
the principal references supporting this discussion is presented in
Section 8.1.
2.1 Emission Processes
Once wastes are deposited in a site, they become subject to
numerous physiochemical processes. Some of these processes result
in the creation of new contaminants. Other processes, arising from
the pressure within the waste system to achieve equilibrium with the
environment, can cause contaminants to migrate through pores in
the soil, or diffuse through liquids, resulting in a release of
contaminants from the site. The contaminants may then escape into
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the atmosphere, if conditions are suitable, through processes such as
volatilization or particle suspension. Emissions can occur directly
from the site itself or after transport off-site in ground water or
surface water.
Two general types of air contaminants are emitted from waste
disposal sites: gases and participate matter. Gases may be organic,
such as methane or chloroform, or inorganic, such as hydrogen
sulfide. Gaseous emissions may arise as a result of volatilization
of liquids such as benzene or toluene, or from reactions involving
chemicals disposed of on the site (e.g., the formation of hydrogen
sulfide). A less common source of gaseous emissions is gas
containers disposed of on the site. In general, the volatilization
of organic liquids is the most common source of gaseous emissions
from disposal sites, although at least one death has occurred from
exposure to gases generated as a result of the interaction of
improperly co-disposed chemicals.
Like gases, particulate contaminants may be either organic or
inorganic. The particulate matter itself may pose a hazard, as in
the case of asbestos particles. Alternately, a hazardous compound
can be absorbed or adsorbed onto the particle. The principal
factors responsible for particulate emissions from wastes sites are
wind and atmospheric turbulence. They can result in resuspension of
surface soil and particulate wastes, and the release of liquid
aerosols. Escaping gases may also carry contaminated particles
with them.
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Table 1 summarizes the result of ambient air monitoring studies
conducted around several wastes disposal sites. Additional
monitoring data are summarized in Appendix A. As can be seen from
Table 1, ambient concentrations of many hazardous substances are
elevated in the areas surrounding major wastes sites. These elevated
hydrocarbon concentrations indicate that uncontrolled wastes sites
may have an adverse impact on the surrounding atmospheric
environment. Further, they indicate, as well, the potential hazard
associated with air emissions from wastes sites. As an example, the
benzene concentrations listed for Love Canal are equivalent to a
_3
lifetime probability of about 10 that a continuously exposed
individual will develop cancer due to the exposure.*
2.2 Factors Determining Emission Rates and Duration
The rate and duration of particulate and gaseous emissions are
influenced by many factors. The importance of each factor differs
from site to site. Two general categories of factors can be
identified: the physical characteristics of the site and the nature
of the wastes in the site. Within the first category, the most
important and easily assessed factors that distinguish the relative
*The benzene risk values are based on a benzene potency factor of
7.4 x 10 per (ug/m ). This value assumes that the exposed
individual weighs 70 kilograms, breathes 20 cubic meters of
contaminated air per day continuously for 70 years. These
assumptions are derived taken from the approach suggested for use
in CERCLA public health evaluations (U.S. Environmental Protection
Agency, 1986). The risk value is intended solely to illustrate
the degree of risk that may be associated with exposure to the
concentrations of certain waste site contaminants.
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TABLE 1
AMBIENT AIR MONITORING RESULTS FOR SELECTED WASTES SITES
Site
Type of Kin Buc
Contaminant (ng/m3)
Benzene
Carbon 111-13687
Tetrachloride
Chlorobenzene T-1127
Chloroform T-6389
Chi oro toluene
Dichloro- T-33783
benzene
(o,m,p)
Love Canal Sylvester Midco I BKK
(ug/m3) (ppb) (ppb) (ppb)
522.7 0.03-3.56 10-2000*
270.0 3.0-4.8
5.0
0.1-172 ND-500*
240.0
0.5-24.0 10.0 5100
0.2-1.0
0.008-7650
0.3-100.5
Chem Dyne
(ppb)
19.2
*ppm
**ug/m3
T: Trace.
ND: Not detected.
Source: Adapted from James, Kinman, and Nutini, 1985,
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TABLE 1 (Continued)
Type of
Contaminant
Kin Buc
(ng/m3)
Site
Love Canal
(ug/m3)
Sylvester
(ppb)
Midco I
(ppb)
BKK
(ppb)
Chem Dyne
(ppb)
1,1-Dichloro-
ethane
1,2-Dichloro-
ethane
1,2-Dichloro-
ethylene
Ethlybenzene
Methylene
Chloride
Tetrachloro-
ethane
Tetrachloro-
ethylene
364-470
T-2173
T-5263
T-1000
32-54
T-2896
334
0.7-11.6
1140
0.2-52
95.0
0.03-0.43
0.03-4.89
0.04-0.24
1.4-3.7
ND-5000*
0.4-3.0
ND-1500*
0.62
*ppm
**ug/m3
T: Trace.
ND: Not detected.
Source: Adapted from James, Kinman, and Nutini, 1985.
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TABLE 1 (Concluded)
Type of
Contaminant
Toluene
Kin Buc
(ng/m3)
Love Canal
(ug/m3)
0.1-6.2
570
Site
Sylvester
(ppb)
Midco I
(ppb)
BKK
(ppb)
Chem Dyne
(ppb)
Trichloro-
ethanes
Trichloro-
ethylene
Vinyl
Chloride
Vinylidene
Chloride
Xylenes
T (1,1,1)
294-357
(1,1,2)
T-10052
15-48.75**
454-555
73
73
1.54
0.05-0.58
ND-1000
0.2-1.8
83-12800*
2-7.3
RD-1200*
0.3-1.3
140
73
1.8
*ppm
**ug/m3
T: Trace.
ND: Not detected.
Source: Adapted from James, Kinman, and Nutini, 1985,
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propensity of sites to emit contaminants are: the type of site
(e.g., landfill, surface impoundment), the size of the site
(including both the quantity of waste deposited and the surface area
of the site), the characteristics of the soil on the site, and the
containment provided by natural and manmade barriers to emissions.
The age of the site is also very important but cannot usually be
readily assessed. Older sites with poor containment have probably
released nearly all of their contaminants while newer sites with
poor containment are probably currently emitting. Additional site
characteristics of lesser importance include: wind speed,
surrounding topography, precipitation, temperature, humidity,
and atmospheric pressure.
The most important factors relating to the nature of the waste
are the contaminant concentrations in the waste and the inherent
physiochemical characteristics of the contaminant that influence its
propensity to migrate through and out of the site to the
atmosphere.
2.3 Contaminant Transport and Transformation
The most common air contaminant release situation is the
emission of contaminants directly into the atmosphere. Once in the
air, the contaminants become subject to atmospheric transport and
transformation processes which dilute the contaminant concentration
as the emissions are "spread out" over an increasing area. The size
of this area effected by an emission is determined by many factors,
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some which simply reduce the contaminant concentration (dilution
and removal) and others that transform the contaminant into other
chemicals (transformation). Together, dilution, removal, and
transformation play a major role in determining the distance from
the site at which the concentration of a contaminant released from
the site into the atmosphere becomes insignificant.
The mechanics of dilution in the atmosphere are generally well
known. There are two principal dilution processes; advection and
diffusion. Advection refers to the transport of contaminants
arising from wind. Diffusion arises as a result of turbulence in
the atmosphere, either thermal or mechanical. These processes are
generally rapid phenomena and are usually modeled in terms of an
exponential function of distance or time (Hanna, Briggs, and Hosker,
1982). The processes that give rise to dilution are also largely
independent of the particular chemicals of concern. The remaining
processes of contaminant removal and transformation in the atmosphere
are more complex and less well known.
One measure of the speed of contaminant removal and
transformation (which in turn would indicate the limit of the
potential exposure area) is the "atmospheric residence time" of the
contaminant of concern. This contaminant-specific parameter is
defined as the amount of time it takes 1-1/e (about 63 percent)
of an initial quantity of a contaminant to be removed from the
atmosphere by physiochemical processes such as photochemical
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oxidation and deposition. Atmospheric residence times for toxic and
hazardous contaminants generally range between 3 and 70 days but may
reach as high as 11,000 days (Cupitt, 1980). Table 2 lists the
atmospheric residence times for typical waste site contaminants.
Many of the common waste constituents, therefore, remain in the
atmosphere for a long period of time and, considering common wind
speeds in the United States, may be transported over long distances.
Because of this, the geographic extent of potential exposure to air
releases from a particular waste site is much greater than that of
any other transport route. However, the magnitude of this exposure
decreases rapidly as the concentration declines due to dilution.
Therefore, although the number of exposed individuals may be large,
the degree of exposure will be low over most of the geographic area
concerned.
A. less common phenomena is the transport of gases through the
soil (sometimes dissolved in ground water) resulting in eventual
emission into the interior of buildings. Once inside the buildings,
these contaminants may become trapped, resulting in the buildup of
contaminant concentrations. Contaminant concentrations in such
instances may reach relatively high levels, as shown in Table 3.
The contaminant concentrations illustrated in this table probably
arose from wastes sites in the Niagara Falls area, such as the Love
Canal disposal site. Thus, situations of low population, high
dosage exposure may occur due to the emissions of air contaminants
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TABLE 2
ATMOSPHERIC RESIDENCE TIMES* FOR SELECTED CONTAMINANTS
DETECTED AT HAZARDOUS WASTES SITES
Compound Residence Time (days)
Carbon Tetrachloride Greater than 11,000
Chlorobenzene 28
Chloroform 120
Dichlorobenzene 39
Dioxane 3.9
Methyl Chloroform 970
Methylene Chloride 83
Nitrobenzene 190
PCB Greater than 11
Toluene 1.9
Trichloroethylene 5.2
Xylenes 0.7
*Time required for a quantity of the individual compound to be
reduced to 1/e of its original value by deposition, chemical
transformation, or similar processes.
Source: Adapted from Cupitt, Larry T., Fate of Toxic and Hazardous
Materials in the Air Environment, (EPA-600/3-80-084), U.S.
Environmental Protection Agency, Research Triangle Park, NC,
August 1980.
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TABLE 3
RANGES OF ESTIMATED LEVELS OF ORGANIC VAPORS
IN AMBIENT AIR OF HOUSEHOLD BASEMENTS
IN NIAGARA FALLS, NY
(ug/m3)
Chemical Concentration Range
Chlorobenzene
Dichlorobenzene Isomers (3)*
Trichlorobenzene Isomers (3)
Tetrachlorobenzene Isomers (2)
Pentachlorobenzene
Chloro toluene Isomers (2)
Dichlorotoluene Isomers (3)
Trichloro toluene Isomers (4)
Tetrachlorotoluene Isomer
Bromotoluene Isomer
Chloronaphthalene Isomer
1,2 - Dichloropropane
Pentachlorobutadlene Isomer
1,3 - Hexachlorobutadiene
Benzene
ND -
0.65 -
0.07 -
0.03 -
T -
1.7 -
0.13 -
0.06 -
0.03 -
T -
0.08 -
1.4
T
0.03 -
T -
4.2
190
33
20
0.49
490
370
0.157
4.1
4.4
3.4
0.41
520
*Values are the sum of the individual isomers detected.
ND: Not detected.
T: Trace.
Source: Pellizzari, Edo D., "Analysis of Organic Vapor Emissions
Near Industrial and Chemical Waste Disposal Sites,"
Environmental Science and Technology, Vol. 16, No. 11,
1982, pp. 781-785.
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from wastes sites. This type of situation is in contrast to the
high population, low dosage exposure situations found as a result of
emissions directly into the atmosphere. This difference in exposure
situation requires differences in scoring mechanisms to account for
the different threats. This phenomenon is not reflected in the
current HRS air pathway, nor in the options discussed in Section 3.
A separate report addresses the situation where building interior
air contamination exists (Wolfinger, I987b).*
*Currently, situations of indoor air contamination are considered
for NPL listing when the contaminated buildings themselves are
considered "sites," (see, for example, Monticello Radiation
Contaminated Properties, NPL Ranking 502, 51 FR 20153).
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3.0 ISSUES IN THE HRS AIR PATHWAY
This chapter presents a discussion of the issues that have been
identified concerning the HRS air pathway. A description of the overall
structure of the HRS and the current air pathway is also provided.
3.1 Background on the Hazard Ranking System
The HRS is designed to assess a site based on the information
compiled in a site inspection. The system is intended to "estimate
the potential hazard presented by releases or threatened releases of
hazardous substances, pollutants and contaminants," and to score the
site based on the risk posed by releases from the site (47 FR 31187).
The HRS addresses three hazard modes: migration, fire and explosion,
and direct contact. The latter two are not used in computing the site
score but are included in the HRS as indicators of the need for
emergency response. The migration mode consists of three potential
migration pathways representing the major routes of environmental
transport common to hazardous wastes sites: ground water, surface
water, and air. Each pathway is structured similarly using three
factor categories: release, waste characteristics, and targets.
The release category reflects the likelihood that the site has,
is, or will release contaminants to the environment. If available
monitoring data indicate that the site is releasing contaminants, then
an "observed release" has been demonstrated.* If no such observed
Information other than ambient monitoring data can be used to
establish an "observed release" in certain situations. These
situations are addressed on a case-by-case basis.
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release can be demonstrated, then the release category is evaluated
using route characteristics and containment factors. These factors
are largely physical characteristics of the sites and their
surrounding environments. It is important to note that the ground
water and surface water routes contain factors for route
characteristics while the air route does not. This permits sites to
be evaluated for their potential to release contaminants to these
two pathways in cases where documentation of a release is lacking.
The current HRS requires that ambient air monitoring data support
the conclusions that the site is, or has been, emitting contaminants
before the site can receive a nonzero air route score.
The waste characteristics category reflects the implicit hazard
of the contaminants that have been or might be released. The
factors included in the waste characteristics categories address
qualitative and quantitative characteristics of the wastes and waste
contaminants found on the sites. The targets category constitutes a
measure of the population and resources that might be adversely
affected by a release. The factor categories and the factors
contained in them are illustrated in Table 4.
Within each pathway, the site is assigned a value for each
applicable factor. The factor values are then multiplied by
weighting factors and summed within factor categories. The resulting
factor category values are then multiplied and normalized to form a
migration route score. Thus, for each site, three migration route
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TABLE 4
HRS SCORING FACTORS
Factor Category
Pathway
Ground Water
Surface
Release Category
Waste
Characteristics
Targets
Monitoring data
or
Depth to aquifer
of concern
Net precipitation
Permeability
Physical state
Containment
Toxicity/persistence
Quantity
Ground water use
Distance/population
Monitoring data
or
Facility slope and
terrain
Rainfall
Distance to receiving
water
Physical state
Containment
Toxicity/persistence
Quantity
Surface water use
Distance/population
Distance to sensitive
environment
Monitoring data
Reactivity/
incompatibility
Toxicity
Quantity
Land use
Distance/population
Distance to sensitive
environment
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scores are produced, each on a scale of 0 to 100. These route
scores are referred to as follows:
• Ground water (S )
gw
• Surface water (S )
sw
• Air (S)
a
The overall site migration score (S ) is then calculated as the
m
root mean square (RMS) of the pathway scores:
7 7 9 1/2
s - (i/i.73)[(s r + (s r + (s r]
m gw sw a
The RMS procedure was chosen to emphasize the highest scoring route
while giving some consideration to secondary and tertiary routes.
This procedure is illustrated in Figure 1.
3.2 Issues in the Current HRS Air Pathway
The principal air pathway issue concerns an apparent
Inconsistency in the release category among the three migration
pathways. Currently, air pathway release category is evaluated
solely on the basis of sampling data, or occasionally other types of
information that indicate contaminants have escaped from the site
into the air (e.g., photographs coupled with soil contamination
samples). If the data indicate that an "observed release" has
occurred, then a release category value of 45 is assigned.
Otherwise, the site is assigned an air pathway release category value
of 0. This latter assignment, combined with the multiplicative
structure of the air pathway, results in the site being assigned an
air route score of 0. In contrast, within the ground water and
22
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Observed Release
0 or 45 pts
or
Route
Characteristics &
Containment*
0-45 pts
GW
SW
A
Waste
Characteristics
— 0-26 pts
— 0-26 pts
— 0-20 pts
*Not Included in Air Pathway
GW = Ground Water Pathway
SW = Surface Water Pathway
A = Air Pathway
Targets
GW —
SW —
A —
0-49 pts
0-55 pts
0-39 pts
Pathway Score
0-100 pts
Normalized
FIGURE 1
BASIC MRS STRUCTURE
-------
surface water pathways, an option Is provided for evaluating the
release category based either on sampling data, ££ on the physical
characteristics of the site and its surrounding environment. These
latter characteristics reflect the potential of the site to release
deposited contaminants.
The inclusion of a potential to release option within the
migration pathways improves the degree to which the HRS score
reflects the relative risk posed by a site. This conclusion is based
on several reasons. First, it is not always possible to determine
that a site is releasing contaminants based on monitoring data. The
contribution of the site to ambient contaminant concentrations may
be masked by the contributions of other sources. Alternately,
adverse environmental conditions (e.g., high wind in the air pathway)
may make the detection of contaminants in the surrounding media
infeasible. Thus, relying solely on monitoring data may result in
sites being assigned scores of zero, even though they pose a threat
(albeit an undetected threat). Second, even if the site is not
currently releasing contaminants, it may begin to release material
in the near future. Relying solely on past information may result
in a site being assigned a zero score, even though that site may
pose a significant threat in the near future. Drum sites are an
example of this possibility. Drums provide adequate, temporary
containment for many wastes but can not generally be relied upon to
contain the wastes over time. Finally, the site may have released
24
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contaminants in the past that were undetected in the site
investigation, that still pose a threat to the surrounding population
and environment. Examples of this possibility are large air emitting
facilities that are currently inactive or abandoned but that caused
area wide soil contamination from contaminant deposition.
As a result of the review of current knowledge on air releases
from hazardous wastes sites, known criticisms of the HRS and the
collective years of experience with the implementation of the HRS,
five additional issues were identified within the context of the air
pathway during development of these options. These issues were
deemed to be sufficiently important to be addressed in the
development of the proposed modifications.
First, the air pathway toxicity value for a site is based on the
toxicity characteristics of the single, most toxic contaminant known
to be present on the site and available for migration. In this
context, contaminants are "available for migration" if they are not
contained on the site by some physical barrier (e.g., the containment
factor value for the portion of the site in which the contaminants is
found is nonzero). This approach is employed regardless of whether
the physiochemical characteristics of the contaminant would prevent
it from escaping in a quantity sufficient to pose a significant
threat to the surrounding area.
Second, concern has been raised about the adequacy of the
current approach to assessing the potential of waste materials to
25
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Interact on a site, either Increasing the rate (or probability) of air
releases or causing the formation of more toxic contaminants than were
originally deposited on the site. The air pathway currently employs a
waste reactivity and incompatibility factor to reflect this potential.
This issue is addressed in a separate report (DeSesso et al., 1986).
The third issue arises from the way in which population is
estimated in the air pathway targets category. These population
estimates are developed in two ways. In the first, population data is
acquired from the local governments in the areas surrounding the
site. This method is most commonly employed when the target radii
encompass entire jurisdictions. In the second method, population is
estimated using estimates of the number of houses in the applicable
areas. These house counts may be provided by local governments or may
be made using maps of the area such as USGS topographic maps. The
number of houses is converted to equivalent population using an
estimate of 3.8 persons per house.
This estimation procedure suffers from several weaknesses.
First, the accuracy of the information is degraded in cases where the
target radii do not encompass entire jurisdictions. The problem of
determining the fraction of the population that resides within the
area defined by the target radii is a serious problem. In these
circumstances, emphasis is often placed on the house counts.
The second weakness lies in the way the house counts are
developed. These counts are often provided by local jurisdictions or
26
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developed from recent local planning maps. In such cases, the house
counts themselves may be very accurate. However, in other instances,
they may be based on outdated maps, such as USGS topographic maps,
and hence may be very inaccurate.
The third weakness arises whenever house counts (accurate or
not) are converted into equivalent population. The use of a uniform
value of 3.8 persons per house ignores spatial and other variations
in household demographics. The availability of 1980 Census data as
an alternative to these data source highlights these weaknesses.
The fourth issue concerns the geographic extent of potential
exposure to air contaminants from a site. The current HRS employs
a radial distance limit of four miles in evaluating the population
exposure factor and distance limit of two miles in evaluating the
land use and sensitive environment factors. Given the potential
geographic extent of exposure indicated by the available information
on atmospheric residence times and long-range transport phenomena
(see, for example, National Research Council, 1983), a re-evaluation
of these "target distance" limits is indicated. A separate report
addressing the question of target distance limits is being prepared
(Wolfinger, 1986a).
The final issue arises from the underlying assumptions embedded
in the current air pathway about the nature of air contaminant
migration. The pathway is designed to rank sites based on the
potential hazard they pose through direct emission of contaminants
27
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to the ambient air, subsequent transport, and eventual inhalation. As
stated previously, situations of indoor air contamination are generally
scored using the air pathway only when the buildings in question are
considered the "wastes site". Due to its underlying assumptions, the
HRS air pathway does not address the potential hazard posed by
migration of air contaminants from a wastes site, through the soil,
and into buildings. This is evident in the definition of observed
release used in evaluating monitoring data. The data used to
establish an observed release must be based on outdoor, ambient air
monitoring. Data from monitoring performed indoors can not be used to
establish an "observed release" unless the contaminated building
itself is the site. Situations may arise in which a significant threat
is posed by a site due to the migration and potential inhalation of
air contaminants that, nonetheless, will not receive a nonzero air
pathway score unless those emissions are sufficient to induce an
elevation in outdoor contaminant concentrations above background. Due
to differences in dispersion characteristics between indoor and
outdoor air, it is possible that indoor air concentrations may reach
significant levels while outdoor air concentration remains relatively
unaffected. Thus, the air pathway observed release assumptions
effectively preclude assigning a positive score to many sites
experiencing indoor air contamination problems.
Further, the current HRS air pathway is somewhat biased against
such sites in the approach taken to evaluate the size of the exposed
28
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population. The target population factor approach requires that a
fairly large population reside near the site to achieve a high value.
A population of at least 1,001 persons residing within 1/4 mile of the
site (3,001 within 1/2 mile or 10,001 within 1 mile) is required to
assign 24 out of a possible 30 points for the population target factor.
This is moderated by the medium values assigned to low populations
near the site (e.g., one person residing within 1/4 mile of the site
permits a site to receive at least 18 out of a possible 30 points).
The approach currently employed reflects the perception that the
average dose to the population, will be small, while the exposed
population will be relatively large. This approach is not consistent
with the high dose, low population exposure situation that would be
characteristic of indoor air contamination sites. Because of this
inconsistency, the HRS air pathway score assigned to a site associated
with indoor air contamination may understate the relative risk posed
by the site by underemphasizing the importance of exposures to small
populations. Thus, the current HRS air pathway may not be adequate
for assessing the relative threat of these sites. A scoring mechanism
for indoor contamination sites is presented in Wolfinger, 1987b.
The air pathway options, discussed in Sections 4 and 5, address
the potential to release issue and the first three of the additional
issues discussed above: evaluation mobility as part of the toxicity
factor, use of waste reactivity and incompatibility data, and
population evaluation.
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3-3 Options for Revising the HRS Air Pathway
The following two chapters describe three options for revising
the HRS air pathway, in response to the issues discussed above. The
principal focus of the options is on methods for evaluating the
potential of a site to release contaminants. The first two Options
(1 and 1A) are very similar, they differ only in the particular
descriptors used in evaluating sites. Both of these options employ a
multiple emission source descriptor approach, using probabilistic
combinatorics to combine the values associated with each descriptor
into an overall value for the site. The third option (Option 2) is a
simpler approach, again employing a choice among several emission
source descriptors, although only the highest scoring applicable
descriptor is used to evaluate the site. This latter approach is
similar to that used in the ground water and surface water pathway.
Numerous additional options were developed, discussed with EPA,
and rejected. These options are summarized in Appendix B.
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4.0 MULTIPLE SOURCE, PROBABILISTIC APPROACHES (OPTIONS 1 AND 1A)
Two similar options for revising the HRS air pathway are
presented in this chapter. The options are consistent in structure
with the ground water and surface water migration pathways of the
current HRS. However, these options use a very different approach
to evaluating the overall potential of a site to release contaminants
than is used in the other pathways. The other pathways evaluate the
overall site release potential based on the potential of that portion
of the site that is most likely to release contaminants (i.e., a
single, "worst" source approach). The options described in this
chapter employ probabilistic combinatorics to assess the site
potential as the aggregate potential of up to three source areas on
the site. The important features of the options are summarized in
Table 5. An alternate, single, "worst" source approach, for the air
pathway is presented in Section 5.
In each option, the analyst evaluates available ambient air
monitoring data to determine if an observed release has occurred.
If the data do not demonstrate an observed release, the analyst may
then evaluate the site based on its potential to release. In either
case, the waste characteristics and targets factors are then
evaluated as indicated. The release, waste characteristics and
targets factor evaluations are next multiplied together and
normalized on a scale of 0 to 100 to form the air pathway score.
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TABLE 5
OVERVIEW OF IMPORTANT FEATURES OF
AIR PATHWAY OPTIONS 1 AND 1A
Option 1 Option 1A
RELEASE CATEGORY Observed release Observed release
based on monitoring based on monitoring
data data
Potential to release Potential to release
based on: based on:
- 30 size-dependent - 12 size-dependent
emission source emission source
descriptors descriptors
(3 size classes) (3 size classes)
- gas and particulate - gas and particulate
mobility factors mobility factors
- detailed gas - less detailed gas
and particulate and particulate
containment factors containment factors
WASTE Combined toxicity- Combined toxicity-
CHARACTERISTICS mobility factor mobility factor
Waste quantity Waste quantity
TARGETS Population Population
Sensitive environment Sensitive environment
Land use Land use
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The following sections discuss the three factor categories
(release, waste characteristics, and targets) and the rating factors
contained in them, for the two air pathway options. The relationship
between the categories and the factors is illustrated in Table 5.
Tables for all of the factors, except containment, are provided in
the text. Tables of containment factors are provided in Appendix D.
Step-by-step instructions for employing Option 1, with an example of
its application, can be found in Appendix C.
4.1 Release Category
The release category reflects the likelihood that the waste
site was, is now, or will be, emitting a significant quantity of any
air contaminant or combination of contaminants. If the available
monitoring data indicate that the site has released hazardous
substances to the air (i.e., an observed release has occurred), then
the likelihood that the site is emitting a significant quantity of
an air contaminant is deemed to be 100 percent (47 FR 31188). In
these cases, a maximum release value would be assigned to the site.
The maximum value possible has been set at 45, maintaining
consistency among the pathways in the current HRS.
If no observed release can be documented, then the site is
evaluated based on its "potential to release". The maximum possible
potential to release value is also 45. The potential to release
factor value reflects the likelihood that the site has released
contaminants in the past or will release contaminants sometime in
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the future, as well as the likelihood that the site is currently
emitting undetected contaminants. This likelihood is formally a
subjective probability.* It is "subjective" in that it is based on
information about the site rather than a frequency of occurrence of
releases at other sites with similar characteristics. It represents,
therefore, the judgment of a group of experts rather than the results
of a statistical sampling program. The options for evaluating
potential to release, discussed below, establish a procedure for
translating information about the physical characteristics of a
wastes site into a subjective probability that the site has, is, or
will emit a significant quantity of contaminant.
4.1.1 Observed Release
Several factors contribute to the determination that an
"observed release" has occurred at a site. Given the wide variety
of emission sources contributing to air pollution, it is nearly
always possible to detect air contaminants near a wastes disposal
site. However, the detected contaminants may not have been released
from the site, but may have originated from numerous sources nearby
or even a long distance away. For example, sulfate originating in
the Ohio River Basin has been detected in Upstate New York, while
indium from Ontario has been detected in Rhode Island (National
Research Council, 1983; Rahn, Lowenthal, and Lewis, 1982).
*For detailed discussions on subjective probability, the reader is
directed to Jaynes, 1958; Kyberg and Smokier, 1964; Raiffa, 1970,
and Stael von Holstein and Matheson, 1978.
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It is essential, therefore, to determine that a significant
portion of the detected contamination arose from the site. A sample
of the "background" air is required to make this determination. The
background sample should be taken close enough to the site to
include the contributions of all other major sources of potential
contaminants but far enough away from the site to exclude
contributions from the site itself. This generally implies that the
background sample be taken upwind from the site and that the "site
sample" be taken downwind of the site.
The difference or ratio of the site and background samples can
be used to determine if an observed release has occurred. If the
ratio or difference is "significant," then the site is considered to
be emitting and an observed release value of 45 is assigned.
Otherwise, an observed release value of 0 is assigned and the
potential to release rating factors are evaluated.
4.1.1.1 Definition of Significant Difference. The question of
"significance" in the context of the HRS air pathway is complex. It
is complicated by the highly variable nature of the atmospheric
environment and the effects of such variations on site emission
characteristics. A release is considered significant if it results
in an elevation in the ambient concentration of any contaminant
above that which would occur if the site were not present.
Furthermore, there must be a reasonable certainty that any elevation
in concentration indicated by the data arose from the site and is
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not simply the result of factors Independent of the site, e.g.,
meteorological conditions and nearby sources. Significance is thus
defined in terms of demonstrating that a release has occurred, not
in terms of the degree of hazard posed by the release. A complete
discussion of the question of significance in the context of the HRS
can be found in Brown, 1986.
4.1.1.2 Implications for Sampling. These considerations place
requirements on the procedures used in sampling. It is imperative
that the site samples not be taken in such a fashion as to
artificially elevate the measured concentrations. This imperative
precludes, for example, the use of samples taken inside of drums or
vents, or samples taken immediately above pools of liquid wastes, as
site samples. The overriding principle concerning a site sample is
that it represent the concentration that an individual might
reasonably be exposed to from the site. In practice, this principle
leads to an operational "rule of thumb" that the site sample should
be taken at least 20 feet away from the emission sources on the site
and that the sample be taken "in the breathing zone".
The background and site samples can then be compared and the
release category evaluated. An obvious problem arises in practice,
however, with this approach. Financial constraints usually restrict
the number of air samples taken. In most cases, the emphasis in air
sampling has been placed on investigator safety rather than site
characterization. Typically, only a few ambient samples are
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available for any particular site for use in assessing observed
releases.
An additional problem arises regardless of the thoroughness of
the sampling plan, the sophistication of the sampling equipment
employed and the care taken during actual sampling. Because the
emissions characteristics of many sites generally depend on highly
variable atmospheric conditions (including temperature, pressure,
wind speed, and stability), it is possible that many sites may not be
releasing a sufficient quantity of contaminants to affect an observed
release during the sampling period. Alternately, the sampling
stations may not be in the "emissions plume" due to unforeseeable
meteorological conditions. Thus, it is all too likely that air
sampling will miss an observed release unless the site emissions
rate is high and sustained, or unless the sampling was performed at
an advantageous time and place.
4.1.1.3 Improvements in the Current Approach. The options
presented here envision a somewhat different approach than is
currently used to evaluate whether an observed release has occurred.
The practice in the current MRS is that a statistically significant
difference between contaminant concentrations in background and site
samples, or an order of magnitude difference between background and
site samples, is sufficient, but not necessary, to achieve an
"observed release". There are numerous problems with the statistical
approach. It is problematic whether the samples taken during a site
37
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investigation meet the requirements for statistical hypothesis
testing of significant difference, e.g., representativeness and
independence. The "order of magnitude" approach, as it is currently
employed, is also weak. There is little scientific basis for
requiring a 10-fold difference to demonstrate an observed release
(as opposed to, for example, a 5-fold or 20-fold difference). This
aspect of determining observed releases is discussed in Brown, 1986.
Currently, there are few restrictions on the samples; the only
uniformly binding requirements being that the samples be taken "in
the breathing zone," i.e., at a height of about five feet and that
they be taken with an instrument that will screen out methane. No
other restrictions apply uniformly and no consideration is given to
the conditions under which the samples are taken.
Because of the problems routinely encountered by investigators
in establishing an observed air release based on current sampling
practices, stricter requirements on monitoring data would be imposed
in these options making it more difficult for a site to achieve an
"observed release". However, the atmospheric conditions under which
the monitoring occurred would be considered, potentially reducing
the level at which a difference between the the background and site
samples would be considered significant. This approach is described
below. The approach employs the ratio of the background and site
samples as the measure of interest. A similar approach can be
developed using the difference between the samples. The thresholds
38
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for significance employed below are provided for illustrative
purposes only and will be further evaluated.
Under "normal" atmospheric conditions, the ratio of the
concentration of any CERCLA contaminant in the site and background
samples would be required to exceed a uniform threshold (e.g., 10)
to achieve an observed release. "Normal" atmospheric conditions are
considered to be those that do not suppress emission from the site.
If atmospheric conditions are such that detected concentrations would
be lowered relative to the site's potential to emit, or if emissions
levels would be suppressed relative to average conditions, then
conditions would be considered "abnormal". Under these conditions
a lower significance threshold would be used, for example, a ratio
of 1.5. If either threshold is achieved, as applicable, then a
release value of 45 would be assigned. Information describing the
sampling conditions, including average wind speed and direction
during sampling, must be provided in support of the sampling data.
Identification of other potential, nearby sources of the detected
contaminants is also desirable. Atmospheric conditions deemed to
meet the criteria for a lower threshold value are listed in Table 6.
This list is intended to be fairly exhaustive, although other
circumstances should be treated on a case-by-case basis.
If implemented, this list of conditions would require further
refinement. Consideration must be given to the trade-off between
the increased flexibility in determining an observed release
39
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TABLE b
SITE CONDITIONS THAT MAKE IT DIFFICULT
TO DEMONSTRATE AN OBSERVED RELEASE
High wind speeds
Low temperature
High relative humidity, including precipitation
Flat and open surrounding terrain
Unstable atmosphere
40
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envisioned here, and the increase in difficulty in assuring the
quality of the data that such a subjective approach entails.
Further guidance on site sampling can be found in the reports
listed in Section 8.2.
4.1.2 Potential to Release
As implied in the above discussions, there are numerous reasons
why an observed release from a site may be difficult to demonstrate
even though a release has occurred. The potential to release portion
of the air pathway is intended to provide for the scoring of sites
when no observed release can be demonstrated.
The approach reflected in the options discussed below uses
information on the physical and chemical characteristics of the
site and the wastes in the site to assess the subjective probability
that the site has, is, or will emit a significant quantity of
contaminants. This subjective probability is implicitly translated
into a scale of 0 to 45 in the tables and worksheets. The
characteristics of a site that indicate its potential to release are
evaluated and the resulting values combined in an algorithm that
reflects the probabilistic aspects of the release category. This
algorithm is discussed in detail below.
This approach differs from the approach currently embodied
in the ground water and surface water pathways, although the
potential to release values in these pathways can be interpreted
probabilistically. Currently, in the other pathways, the evaluation
41
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of the release potential of a site employs a single, "worst" source
approach. In these pathways, different areas of the site are
evaluated according to particular criteria (e.g., physical state and
containment) and the value for the highest scoring area (i.e., the
single, "worst" source) is used as the release value. Interpreted
probabilistically, the release category in the ground water and
surface water pathways reflect the maximum probability that some
portion of the site will release contaminants. This "maximum" value
is actually less than the combined probability that some portion of
the site will release contaminants. The combined probability is
employed in Options 1 and 1A discussed below. The option discussed
in Section 4 (Option 2) employs the approach embodied in the current
ground water and surface water pathways.
The overall approach discussed below was chosen for two
fundamental reasons. First, the principal alternate approaches
(those based on emission estimation equations) were deemed to be too
complex and required data that would be impossible to gather in a
site investigation (e.g., mass transfer coefficients for contaminants
in site-specific waste mixtures). Second, this approach is
consistent with the probabilistic nature of the potential to
release component of the pathway and employs most of the principal
factors that determine site emission characteristics. This approach
better reflects the probability that the overall site will emit
contaminants, in comparison to the single maximum approach currently
42
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employed in the other pathways, and hence, results in a site score
that better reflects the risk posed by the site. The principal
negative aspect of the approach taken is its computational
complexity.
This complexity is mitigated, however, by the development and use of
descriptive tables and easily used references (e.g., Versar, 1984).
As indicated in Table 5, four site characteristics are employed
in assessing the potential of a site to emit air contaminants:
• Emission source descriptor
• Size
• Overall contaminant mobility
• Containment
The first two characteristics are combined into a single factor.
The size-dependent emission source descriptors constitute a
simple classification of sites according to type of "disposal"
employed on the site (e.g., landfill or surface impoundment). The
use of these descriptors reflects the belief of the author that the
type of site is important in determining the rate and duration of
emissions. The importance of the type of disposal practice employed
on the site in determining organic compound emissions is indicated
in Table 7. This table indicates that the disposal practice is one
of the principal determinants of the rate of volatilization of
organic compounds from a site. For example, the data indicate that
emission rates from landspreading will be greater for a shorter
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TABLE 7
TIME NEEDED FOR 75 PERCENT OF SELECTED COMPOUNDS
TO VOLATILIZE FOR VARIOUS DISPOSAL METHODS
Contaminant
Phenol
Tetrachloroethylene
Benzene
Ethanol
Methyl Ethyl Ketone
Ethylactetate
Tricolor oethylene
Chloroform
Carbon tetrachloride
Dichloroethane
Dimethylamine
Ethylene
Pentane
Dichloroethylene
Landspreadlng
39 days
*
5 days
16 hours
7 hours
*
7 hours
*
*
3 hours
0.7 hours
*
*
*
Disposal
Method
Surface
Impoundment
*
12.4 days
11.6 days
*
*
*
11.4 days
11.3 days
10.3 days
9.1 days
*
7.4 days
*
*
Covered
Landfill
333 years
*
41 years
*
*
2.6 years
2 years
11 months
*
11.7 months
*
*
7.8 months
4.2 months
*Data not available to calculate rate for this substance.
Source: Scheible et al., 1982.
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period than those of covered landfills, all other characteristics
being the same.
Contaminant mobility refers to the overall propensity of the
contaminants on the site to migrate to the surface and escape into
the atmosphere, based on their physiochemical characteristics.
Contaminant mobility is reflected with separate factors for gaseous
and particulate contaminants. Table 7 also illustrates the
importance of the characteristics of the contaminants in the site.
As indicated in Table 8, phenol is generally less mobile than
dichloroethane. This relative mobility is evident as well in the
longer retention time indicated for phenol in a landfill (333 years)
as compared with dichloroethylene (4.2 months).
Containment refers to the physical characteristics of the site,
either manmade or natural, that act to restrict emissions and
contain the contaminants on the site. Containment is also reflected
with separate gaseous and particulate factors. Containment is the
single most important factor determining potential to release, hence
its employment as a multiplicative rather than an additive factor.
The overall approach to evaluating the potential of a site to
release contaminants is as follows. The emission sources on the
site are identified and classified using the emission source
descriptors. The size of each emission source is assessed and a
size class assigned to each emission source descriptor. From this
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TABLE 8
DATA ON MOBILITY OF PHENOL AND DICHLOROETHYLENE
Contaminant
Phenol
Dichlorethylene (1,1)
VP*
0.62
630.1
AQ*
1.3 E-6
1.5 E-2
RS*
2.0 E-l
202
*VP: Vapor pressure In units of mmHg at 25° C.
AQ: Henry's constant in units of atm-m^/mol.
RS: Relative soil volatility as defined in Versar,
46
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information, a size-dependent emission source descriptor value is
assigned to up to three of the selected descriptors.
The contaminants present in the areas represented by the
descriptors are identified and used to calculate a gaseous
contaminant mobility value for each descriptor. The particulate
mobility value for each selected descriptor is calculated based on
characteristics of the climate surrounding the site (primarily wind
speeds, precipitation, and temperature). The two mobility values
are combined and added to the emissions source descriptor value, for
each descriptor selected.
The gas and particulate containment aspects of the areas
represented by each of the three selected descriptors are evaluated
and their values combined into a single containment value for each
selected descriptor.
The sum of the descriptor and mobility values are then
multiplied by the containment value to form an overall value for
each of the three selected descriptors. This value represents the
probability that the sources represented by the selected descriptor
has, is, or will emit a significant amount of contaminant. The
three descriptor-specific values are then combined into an overall
potential to release value for the site using the appropriate
probability formula (see Section 4.1.2.4).
The relationship of the potential to release value to the
probability that a site will emit a significant quantity of air
47
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contaminants (i.e., the emissions probability) is as follows. The
size-dependent site descriptor value reflects the subjective
probability that an uncontained site (containment value equivalent
to 3) with relatively immobile contaminants (mobility value equivalent
to 0) could release a significant quantity of air contaminants. The
emission probability is equal to the value divided by 15. For
example, the emission source descriptor value assigned to a small
landfarm is 6.* Thus, the probability that such a source, poorly
containing relatively immobile contaminants, would emit a significant
quantity of air contaminants is estimated at 6/15 (or, equivalently,
18/45).
The mobility factor serves to increase the emission probability
based on the overall mobility of the contaminants associated with the
emission source descriptor in question. Continuing the example, the
emission probability for a similar landfarm with very mobile
contaminants (mobility value of 5) would be 11/15 (or [6 + 5]/15).
The containment value serves to decrease the probability based
on the degree to which physical barriers present on the site would
reduce emissions. Thus, the emission probability for a small,
relatively uncontained (containment value of 2) landfarm with very
mobile contaminants would be 22/45 (or 11/15 x 2/3). This corresponds
to an overall value for the landfarm of 22 on a scale of 0 to 45.
*This example employs the value given in Table 13 for a small
landfarm.
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Values based on any other scale can be readily developed by
multiplying the probabilities by the desired scale.
The following discussion describes the factors and this approach
in greater detail.
4.1.2.1 Size-Dependent Emission Source Descriptors. A list of
emission source descriptors and associated definitions was developed
based on the results of the literature review, an examination of the
descriptors used by investigators in describing candidate NPL sites
and a review of the definitions promulgated under RCRA. Lists of
the descriptors for Option 1 and 1A are provided in Table 9 and
Table 10, respectively. Complete definitions are provided in
Appendix D. The differences in the number and definitions of the
emission source descriptors listed in Tables 9 and 10 constitute the
principal differences between the options.*
The selection of emission source descriptor is generally left
up to the investigator evaluating the site. However, there are
necessary restrictions in the selection process. First, the
descriptors selected should be the ones that best describe the site.
It contravenes the system to call a puddle of water a "surface
impoundment," for example, simply to achieve a higher site score.
Second, in order to use a descriptor, information indicating that
hazardous contaminants have been located or deposited in the area
*The only remaining differences between the options lie in the
containment factor definitions. These differences arise largely
from the differences in emission source descriptors, as well.
49
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TABLE 9
OPTION 1 EMISSION SOURCE DESCRIPTORS
Code Descriptor
Aboveground or Iaground Tanks:
01 • Tanks intact
02 • Tanks broken
03 Active Fire Site
04 Belowground Injection
05 Belowground Tanks
Contaminated Surface Soil:
• Background at or above analytical detection limit;
06 - Contamination level at or below background
07 - Contamination level above background but not
significantly above background
08 - Contamination level significantly above background
• Background below analytical detection limit;
09 - Contamination level below analytical detection limit
10 - Contamination level above analytical detection limit
Exposed Drum Site:
11 • Drums broken
12 • Drums intact
Inactive Aboveground Fire Site:
13 • Re-ignition expected
14 • Re-ignition not expected
Inactive Belowground Fire Site:
15 • Re-ignition expected
16 • Re-ignition not expected
17 Landfarm/Landtreatment
50
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TABLE 9 (Concluded)
Code Descriptor
Landfill:
13 • With both biodegradable material and exposed drums
19 • With biodegradable material but without exposed drums
20 • All other situations
21 Open Pit
Spill Site:
.22 • Spill dry
23 • Spill wet
Surface Impoundment:
24 • Dry; evidence of waste contamination near surface
25 • Dry; all other situations
26 • Wet; evidence of waste contamination near surface
27 • Wet; all other situations
28 Surface Water Body or Outfall
29 Waste Pile
30 Emission Sources Not Elsewhere Specified
51
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TABLE 10
OPTION 1A EMISSION SOURCE DESCRIPTORS
Code Descriptors
01 Active Fire Site
02 Belowground/Buried Containers
03 Contaminated Soil
04 Dry Surface Impoundment
05 Inactive Fire Site
06 Intact Exposed/Aboveground Containers
07 Landfarm
08 Landfill
09 Nonintact Exposed/Aboveground Containers
10 Waste Pile
11 Wet Surface Impoundment
12 Emission Sources Not Elsewhere Specified
52
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covered by that descriptor is required before that descriptor can
be used. Third, generally a descriptor can be used only once in
describing a site. This principle applies unless it can be
established that two different areas described by the same descriptor
received different wastes or are otherwise dissimilar. Further, the
area described by a selected descriptor should be as homogenous as
possible. For example, if a site contains two different landfills
with similar waste and containment characteristics, then the
landfill descriptor may be used once, referring to both landfills
simultaneously. However, if two dissimilar landfills are present on
the site, the "landfill" descriptor should be employed twice. A
fourth restriction associated with the size of the source described
by the selected descriptor is discussed below.
Three size categories are defined for emission source
descriptors using data developed in 0'Sullivan, 1982 and Vogel and
0*Sullivan, 1983. Size category definitions were developed, for
convenience, both in units of surface area and equivalent volume, as
applicable. Different values of depth were employed following the
assumptions in the aforementioned references. The size categories
were developed using the percentiles of the distribution of RCRA
Part A volume and surface area data as presented in the references.
The RCRA Part A data was the only information source that could be
identified for size-related data. The applicability of the data to
CERCLA sites is problematic.
53
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For the purposes of evaluating the size of the area covered by
a particular emission source descriptor, only the total area
containing waste materials should be included. When two areas are
covered by the same descriptor, then the sum of their respective
areas is used in evaluating the overall area. For example, if a site
contains two similar landfills (similar in waste and containment
characteristics), the size associated with the "landfill" descriptor
is the sum of the sizes of the landfills. If the "landfill"
descriptor is used twice to reflect the presence of two dissimilar
landfills, then the size associated with each use of the descriptor
is the size of the applicable landfill. Size categories for the
Option 1 and 1A emission source descriptors are presented in
Tables 11 and 12, respectively.
The use of these size categories places an additional
restriction on the investigator's selection of emission source
descriptors. In general, the areas covered by the descriptors
selected must be larger than the minimum size in the "Small" size
category. If this constraint cannot be met, then the investigator
must use only the descriptor whose size is greatest relative to the
minimum size in its "Small" category.
A set of values were developed for the various size-dependent
emission source descriptors based on the judgment of the author
concerning the subjective probability that a generic emissions
source of specified description and size would emit a significant
54
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TABLE 11
OPTION 1 SIZE RANGES
Descriptor
Belowground Tanks (cubic feet)
Small
Medium
Large
Contaminated Surface Soil (square feet)
Small
Medium
Large
Exposed Drum Site (number of drums)
Small
Medium
Large
Inground or Aboveground Tanks (cubic feet)
Small
Medium
Large
Inactive Aboveground Fire Site (square feet)
Small
Medium
Large
Inactive Belowground Fire Site (square feet)
Small
Medium
Large
Landfarm/Landtreatment (square feet)
Small
Medium
Large
Landfill (cubic feet)
Small
Medium
Large
Size Range
1,000 - 8,900
8,900+ - 470,000
greater than 470,000
11,000 - 200,000
200,000+ - 2,600,000
greater than 2,600,000
1 - 250
251 - 10,000
greater than 10,000
1,000 - 8,900
8,900+ - 470,000
greater than 470,000
11,000 - 200,000
200,000+ - 2,600,000
greater than 2,600,000
74,000 - 190,000
190,000+ - 21,000,000
greater than 21,000,000
11,000 - 200,000
200,000+ - 2,600,000
greater than 2,600,000
74,000 - 190,000
190,000+ - 21,000,000
greater than 21,000,000
55
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TABLE 11 (Concluded)
Descriptor
Landfill (square feet)
Small
Medium
Large
Open Pit (cubic feet)
Small
Medium
Large
Open Pit (square feet)
Small
Medium
Large
Spill Site (square feet)
Small
Medium
Large
Surface Impoundment (cubic feet)
Small
Medium
Large
Surface Impoundment (square feet)
Small
Medium
Large
Surface Water Body or Outfall (square feet)
Small
Medium
Large
Waste Pile (cubic feet)
Small
Medium
Large
Waste Pile (square feet)
Small
Medium
Large
Size Range
11,000 - 28,300
28,300+ - 790,000
greater than 790,000
74,000 - 190,000
190,000+ - 21,000,000
greater than 21,000,000
11,000 - 28,300
28,300+ - 790,000
greater than 790,000
11,000 - 200,000
200,000+ - 2,600,000
greater than 2,600,000
1,000 - 8,900
8,900+ - 470,000
greater than 470,000
300 - 2,700
2,700+ - 71,000
greater than 71,000
300 - 2,700
2,700+ - 71,000
greater than 71,000
130 - 1,300
1,300+ - 88,000
greater than 88,000
36 - 360
360 - 10,600
greater than 10,600
56
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TABLE 12
OPTION 1A SIZE RANGES
Descriptor
Belowground/Buried Containers (cubic feet)
Small
Medium
Large
Exposed/Aboveground Containers (cubic feet)
Small
Medium
Large
Contaminated Soil (square feet)
Small
Medium
Large
Inactive Fire Site (square feet)
Small
Medium
Large
Landfarm/Landtreatment (square feet)
Small
Medium
Large
Landfill (cubic feet)
Small
Medium
Large
Landfill (square feet)
Small
Medium
Large
Open Pit (cubic feet)
Small
Medium
Large
Size Range
1,000 - 8,900
8,900+ - 470,000
greater than 470,000
6 - 1,400
1,401 - 56,000
greater than 56,000
11,000 - 200,000
200,000+ - 2,600,000
greater than 2,600,000
74,000 - 190,000
190,000+ - 21,000,000
greater than 21,000,000
11,000 - 200,000
200,000+ - 2,600,000
greater than 2,600,000
74,000 - 190,000
190,000+ - 21,000,000
greater than 21,000,000
11,000 - 28,300
28,300+ - 790,000
greater than 790,000
74,000 - 190,000
190,000+ - 21,000,000
greater than 21,000,000
57
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TABLE 12 (Concluded)
Descriptor
Open Pit (square feet)
Small
Medium
Large
Spill Site (square feet)
Small
Medium
Large
Surface Impoundment (cubic feet)
Small
Medium
Large
Surface Impoundment (square feet)
Small
Medium
Large
Surface Water Body or Outfall (square feet)
Small
Medium
Large
Waste Pile (cubic feet)
Small
Medium
Large
Waste Pile (square feet)
Small
Medium
Large
Size Range
11,000 - 28,300
28,300+ - 790,000
greater than 790,000
11,000 - 200,000
200,000+ - 2,600,000
greater than 2,600,000
1,000 - 8,900
8,900+ - 470,000
greater than 470,000
300 - 2,700
2,700+ - 71,000
greater than 71,000
300 - 2,700
2,700+ - 71,000
greater than 71,000
130 - 1,300
1,300+ - 88,000
greater than 88,000
36 - 360
360 - 10,600
greater than 10,600
58
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amount of air contaminants. The author's opinion is based on the
literature review and a review of the limited air monitoring data
available in the NPL site files and remedial investigation reports.
The quality and coverage of the available monitoring data preclude
the calculation of "objective," frequency-based probabilities.
The initial values were modified, as necessary, after
consultation with personnel from the EPA Environmental Response
Team, Hazardous Waste Engineering Research Laboratory, and Office
of Air Quality Planning and Standards. Values for Option 1 and 1A
emission source descriptors are presented in Tables 13 and 14,
respectively. Values on any other desired scale can be developed by
dividing the listed value by 15 and multiplying by the maximum of
the desired scale. For example, the value for a small landfarm,
evaluated on a scale of 0 to 20, would be 6/15 x 20 or 8.*
4.1.2.2 Contaminant Mobility. Contaminant mobility is
evaluated using the combination of two mobility factors, one
addressing gaseous contaminants, the other addressing particulate
matter. The gas mobility factor reflects the potential of the
contaminants in a site to migrate through the site to the surface/
air interface and escape as a gas. The factor is based on three
physiochemical characteristics of the contaminants: vapor pressure,
Henry's constant, and dry relative soil volatility. Vapor pressure
*Such changes of scale would require adjustments in the mobility
factor value scales and in the conversion factors used on the
worksheets (i.e., 45 and 2,025).
59
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TABLE 13
OPTION 1 EMISSION SOURCE DESCRIPTORS AND VALUES
Values
ode Descriptors
01 Aboveground or Iaground Tanks:
Tanks intact
02 Aboveground or Inground Tanks:
Tanks broken
03 Active Fire Site
04 Belowground Injection
05 Belowground Tanks
06 Contaminated Surface Soil:
Background at or above
analytical detection limit;
contamination level at or
below background
07 Contaminated Surface Soil:
Background at or above
analytical detection limit;
contamination level above
background but not significantly
above background
08 Contaminated Surface Soil:
Background at or above
analytical detection limit;
contamination level significantly
above background
09 Contaminated Surface Soil:
Background below analytical
detection limit; contamination
level below analytical
detection limit
10 Contaminated Surface Soil:
Background below analytical
detection limit; contamination
level above analytical
detection limit
11 Exposed Drum Site: Drums broken
12 Exposed Drum Site: Drums intact
13 Inactive Aboveground Fire Site:
Re-ignition Expected
14 Inactive Aboveground Fire Site:
Re-ignition Not Expected
Medium
8
10
10
10
60
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TABLE 13 (Concluded)
Values
Code Descriptors Small Medium
15 Inactive Belowground Fire Site: 4 6
Re-ignition Expected
16 Inactive Belowground Fire Site: 2 4
Re-ignition Not Expected
17 Landfarm/Landtreatment 6 8
18 Landfill: 6_ 8_
With both biodegradable material
and exposed drums
19 Landfill: 4_ 6_
With biodegradable material but
without exposed drums
20 Landfill: All other situations 1_ 3_
21 Open Pit 5 7_
22 Spill Site: 4 6_
Spill dry
23 Spill Site: 6_ 8_
Spill wet
24 Surface Impoundment: 6 8
Dry; evidence of waste
contamination near surface
25 Surface Impoundment: 2 4 6
Dry; all other situations
26 Surface Impoundment: 5 7 9
Wet; evidence of waste
contamination near surface
27 Surface Impoundment: 1 3 5_
Wet; all other situations
28 Surface Water Body or Outfall 3_ 5_ 7_
29 Waste Pile 5_ 7_ 9_
30 Emission Sources Not Elsewhere: 3 3 3_
Specified
61
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TABLE 14
OPTION 1A EMISSION SOURCE DESCRIPTORS AND VALUES
Code Descriptors
01 Active Fire Site
02 Belowground/Buried Containers
03 Contaminated Soil
04 Dry Surface Impoundment
05 Inactive Fire Site
06 Intact Exposed/Aboveground
Containers
07 Landfarm
08 Landfill
10 Nonintact Exposed/Aboveground
Containers
10 Waste Pile
11 Wet Surface Impoundment
12 Emission Sources Not Elsewhere
Specified
Values
Small
10
1
6
5
5
1
6_
5
8
5
5
3
Medium
10
3
8
7
7
1
8_
7
9
7
7
3
Large
10
5
10
9
9
1
10
9
10
10
9
3
62
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provides a measure of the propensity of a contaminant to escape from
a pure liquid or solid. Henry's constant (defined as the ratio of
the partial pressure of a gas in solution to the mole fraction of
the gas in solution) provides a measure of the propensity of a
contaminant to escape from a solution. Relative soil volatility is
a measure of the tendency of a gas to move through and escape from
soil. The derivation of this complex factor is described in Versar,
1984.
A vector of values for each of these characteristics can be
assigned to a contaminant using the evaluation techniques developed
by Versar and summarized in Table 15. Versar ranked wastes and
contaminants based on their vapor pressures, Henry's constant and
relative soil volatility in order to identify, for example, highly
volatile wastes. The associated values were assigned by the author.
Referring to the data presented in Table 8, the vector of mobility
values for phenol would be (2,1,2), while that of dichloroethylene
would be (3,3,3).
An average of the three values for five contaminants present on
the site is used in evaluating the gas mobility value. An average
is used as an attempt to address the effects of co-disposal and
resulting mixing of wastes and waste contaminants. In theory, the
average of several contaminants characteristics would be a better
estimator of the mobility of contaminants mixed in a matrix than the
characteristics of any single contaminant. The value of five was
63
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TABLE 15
GAS MOBILITY VALUES
Level
High
Medium
Low
Very Low
Vapor Pressure Mobility (VP)
Definition
Above 10 torr*
Above 10" 3 - 10 torr
10"5 - 10~3 torr
Less than 10"^ torr
Value
3
2
1
0
Level
High
Medium
Low
Very Low
Aqueous Volatility (AQ)
Definition**
Above 10~3
Above ID"5 - 10"3
10~7 - 10~5
Less than 10~7
Value
3
2
1
0
Level
High
Medium
Low
Very Low
Relative Soil Volatility (RS)
Definition***
Above 1
Above 10~3 - 1
10-6 _ 10-3
Less than 10~"6
Value
3
2
1
0
*Torr is a unit of pressure equal to 1/760 of an atmosphere.
**Based on Henry's constant.
***flased on dry relative soil volatility as defined in Versar, Inc.,
Physical-Chemical Properties and Categorization of RCRA Wastes
According to Volatility, Final Draft Report, Versar, Inc.,
Springfield, VA, September 28, 1984.
64
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chosen as being large enough to meet the objective of better
estimating overall mobility and as being small enough to be useable
at most sites.
Since different contaminants are found in different areas of a
site, the choice of contaminants to be used in evaluating gas
mobility should be consistent with the choice of emission source
descriptor for the portion of the site in question to the extent
possible given information about the site. For example, when
evaluating the landfill portion of a site, only those contaminants
found in the landfill portion should be used in evaluating the gas
mobility value. As many contaminants as possible (up to five) should
be used in this calculation. The methodology will accommodate less
than five contaminants without penalizing the site, since the average
of the nonzero values is used. The approach for evaluating gas
mobility is summarized in Table 16. An example calculation of the
gas mobility factors value for a hypothetical site is given in
Appendix C (Table C-12).
Particulate mobility reflects the potential for particles on
the surface of a site to be formed and entrained in the atmosphere,
escaping from the site. These particles may be contaminated soil,
dry hazardous substances (such as asbestos), or liquid aerosols.
The approach taken in the particulate mobility factor is based on
the equation for fugitive dust emissions from a limited particle
reservoir developed by Cowherd et al. (1985). The limited reservoir
65
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(1)
(2)
(3)
(4)
(5)
TABLE 16
METHOD FOR EVALUATING GAS MOBILITY
Emission Source Descriptor Code
Contaminant VP AQ RS
Code Value Value Value Sum
(6) Average of nonzero values in last column of
lines 1 through 5
GAS MOBILITY TABLE
Range of Average Value
Greater than
or equal to Less than Value
0 30
3 5 1
5 7 2
7 10 3
66
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equation was chosen after consultation with Gregory Muleski (a
co-author of the above report) as being most applicable to CERCLA
sites. In simplifying this equation for use in these HRS options,
the assumption is made that the three controlling factors in fugitive
emissions (erosion force, threshold wind speed, and Thornthwaite
PE Index) are equally applicable to both "solid" waste materials
and liquid aerosols.
The approach taken is a simplification of the Cowherd et al.
equations. Other factors included in the equations but excluded here
are frequency of disturbance and vegetative cover. The frequency of
disturbance is not included as (1) not generally differentiating
among CERCLA sites and (2) too difficult to estimate. Vegetative
cover is addressed in the containment factor.
Using the reduced form of the Cowherd et al. equation, the
following particulate mobility index (I) is defined:
I = (u+ - ut)/(PE)2
where: u = Fastest mile at nearest airport (meters per second)
u = Threshold wind speed at 7 meters (meters per second)
PE = Thornthwaite PE Index
The fastest mile (u ) is defined as the velocity of the
fastest wind the duration of which was equivalent to a travel
distance of one mile. For example, in order for a wind speed of
120 miles per hour to be a fastest mile, the duration of the
associated wind would have to exceed 30 seconds. In this equation,
67
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it is a measure of the force that the wind applies In eroding soil.
For the purpose of determining site particulate mobility, the average
of the monthly, historical fastest miles is used as u . This
average is used rather the historical maximum, since the average is
a better measure of the wind erosion force that would be routinely
applied to the site. The historical fastest mile is simply the
maximum of the monthly fastest miles and is potentially very
sensitive to very rare events, e.g., tornados. As such, it is not
as good a measure of routine wind erosion force as the average of
the monthly fastest miles.
Data on the fastest mile can be obtained from the Local
Climatological Data Annual Summaries (LCD) for the latest available
year, listed under the Normals, Means, and Extremes. Data for the
weather station that is closest to the site and listed in the LCD
should be used.
The threshold wind speed (u ) is the minimum speed required
to entrain particles. It can be estimated using the procedure in
Cowherd et al. or it may be assumed to be 12.5 meters per second.
This latter, worst-case value is based on a threshold friction
velocity of 75 centimeters per second (the lowest for which the
limited reservoir equation is applicable) and a roughness height
of 1 centimeter (corresponding to a plowed field). Cowherd et al.
describes the procedure for deriving the default threshold wind
speed.
68
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The Thornthwaite PE Index is a surrogate measure of the relative
moisture content of the soil. It can be read from Figure 2, or
calculated as follows (Thornthwaite, 1931):
12
PE = 115 x [P/d - 10)]10/9
where: PE = Thornthwaite PE Index
P. = Mean precipitation for month i in inches
T. = Mean temperature for month i in degrees F
Data on the mean precipitation and temperatures for each month
can also be found in the LCD. Again, data for the weather station
nearest to the site and listed in the LCD should be used.
Once the particulate mobility index I has been calculated, the
particulate mobility factor value is calculated as follows:
Particulate Mobility Value = 4 + log1Q I
rounded-off to the nearest whole number. If log,Q I exceeds 4,
the factor is assigned a value of 0. If log-,Q I is less than 0.5
(i.e., the calculated value would exceed 3) then the factor is
assigned a value of 3. The value of 4 in the formula is a scaling
factor needed to adjust the value to a scale of 0 to 3. Table 17
provides an equivalent way to determine the particulate mobility
value from the index without requiring the calculation o'f log,Q I.
The alternate is derived directly from the above equation. An
example of the calculation of the particulate mobility index,
69
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Source: Cowherd et al., 1985
FIGURE 2
MAP OF PE INDEX FOR STATE CLIMATIC DIVISIONS
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TABLE 17
ALTERNATE METHOD FOR ASSIGNING
PARTICULATE MOBILITY FACTOR VALUES
Particulate Particulate
Mobility Index (I) Mobility Value
Less than 3.16 x 10~4 0
3.17 x 10~4 - 3.16 x 10~3 1
3.17 x 10~3 - 3.16 x 10~2 2
Greater than 3.17 x 10~2 3
71
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employing the equation for the Thornthwaite PE Index, is presented
in Appendix C (Table C-13).
The expected distribution of locations in the United States
according to particulate mobility value is indicated below:
Value Percent of Sites
0 6
1 47
2 31
3 16
This distribution was developed using data from a random selection
of 30 airports across the country. To the extent that the geographic
distribution of airports is indicative of the distribution of sites,
this distribution of particulate mobility values reflects the
distribution of hazardous wastes sites particulate mobility values,
as well.
The combined mobility value is calculated from the gas and
particulate mobility values using Table 18. If a scale other than 0
to 5 is desired, it can be calculated by multiplying the values by
the ratio of the maximum of the desired scale and 5.*
4.1.2.3 Containment. Containment refers to the physical
characteristics of a site that inhibit or reduce emissions. It is
generally the most important determinant of the emission rate at a
site. Containment-related characteristics range from natural factors
*In such cases, adjustments would also have to be made to the
emission source descriptor and containment values as well as to the
conversion factors employed on the worksheets.
72
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TABLE 18
COMBINED MOBILITY FACTOR MATRIX
Gas Mobility Value
0 1 2 3
Particulate 0: 0 1 23
Mobility 1:1 2 34
Value 2: 2 3 45
3: 3 4 55
73
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such as vegetative cover to artificial, synthetic covers. Separate
containment factors were developed for gas and particulate containment.
There are also sufficient differences among the containment factors
that might be associated with different types of sites to require that
different containment descriptors be developed for each emission
source descriptor. Many emission source descriptors share the same or
similar containment descriptors. Numerous sources were examined to
develop containment factors. The most important sources are listed in
Section 8.3.
Once the containment descriptors were developed, a subjective
assessment of their efficiency in reducing potential emissions was made
and values assigned. The descriptors and values were then reviewed in
conjunction with the emission source descriptors and values and changes
made as necessary. Table 19 lists examples of the gas and particulate
containment factors and values. The combined containment value is
calculated from the gas and particulate containment values using
Table 20. Complete lists of containment factors for both options can
be found in Appendix D.
The choice of an applicable containment descriptor depends on the
judgment of the analyst evaluating the site. Containment should be
evaluated, however, in the area of the hazardous contaminants. It
should reflect the barriers to contaminant migration present on the
site. For example, assume a site contains two tanks; one containing
hazardous waste, the other containing liquids of unknown composition.
74
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TABLE 19
EXAMPLES OF CONTAINMENT FACTORS AND VALUES
Particulate C oatainment—Landfill Value
• Site covered with an essentially impermeable and 0
maintained cover or heavily vegetated with no exposed
soil or waste-bearing liquids (e.g., paved-over).
• Site substantially vegetated or totally covered 1
with a maintained nonwater-based dust suppressing
fluid. Little exposed soil or waste-bearing liquids.
• Site lightly vegetated or partially covered with a 2
maintained nonwater-based dust suppressing fluid.
Much exposed soil or waste-bearing liquids.
• Site substantially devoid of vegetation with a large 2
percentage of exposed soil or waste-bearing liquids.
No other cover. Facility slope less than 10 degrees
or unknown.
• Site substantially devoid of vegetation with a large 3
percentage of exposed soil or waste-bearing liquids.
No other cover. Facility slope greater than 10 degrees.
Gas Containment—Landfill Value
• Uncontaminated soil cover in excess of six inches. 0
• Uncontaminated soil cover greater than one inch and 1
less than six inches; cover soil resistant to gas
migration.
• Uncontaminated soil cover less than six inches; cover 1
soil type unknown.
• Uncontaminated soil cover greater than one inch and 2
less than six inches; cover soil not resistant to gas
migration.
• Uncontaminated soil cover less than one inch; cover soil 2
resistant to gas migration.
• Uncontaminated soil cover less than one inch; cover soil 3
not resistant to gas migration.
• Covering soil contaminated with waste contaminants at 3
surface and no synthetic cover between surface and bulk
of waste materials.
75
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TABLE 20
COMBINED CONTAINMENT FACTOR MATRIX
Gas Containment Value
0 1 2 3
Particulate 0: 0 1 2 3
Containment 1:1 1 2 3
Value 2: 2 2 2 3
3: 3 3 33
76
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Assume also that the tank with known contents is structurally intact
while the other tank is not. The containment for the tanks should be
evaluated based on the intact, known-waste tank, not the nonintact
tank.
4.1.2.4 Potential to Release Scoring Algorithm. The algorithm
used to combine the size-dependent emission source descriptor,
mobility, and containment values is complex. In general, several
emission source descriptors will apply to a given site. Given this
consideration and the differences between emission source descriptor
values, several descriptors are needed to adequately evaluate the
potential of a site to release contaminants. Both Option 1 and 1A
provide for the use of up to three descriptors for a site. The use
of more than three descriptors would introduce a level of complexity
into the resulting calculations that is not commensurate with
possible gains in the site assessment results. The descriptors
selected by the person evaluating the site, therefore, should be
the three that best describe the emission potential of the site.
Mobility and containment values are evaluated for each descriptor
selected based on the characteristics of the site and its
contaminants to which the descriptor applies. A total value for
each descriptor is calculated as the sum of the size-dependent
emission source descriptor value and the combined mobility value
multiplied by the combined containment value. The three resulting
values are then combined, using the equation for the probability of
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the union of three independent events,* to form a site potential to
release value. This method of calculating site potential to release
values is illustrated in Table 21. This approach is recommended
since it is the only approach consistent with the underlying
assumption that the release category reflects the probability that
some portion of the site has, is, or will release a significant
quantity of air contaminants.
4.2 Waste Characteristics Category
The waste characteristics category reflects the degree of hazard
posed by the contaminants that are, or might be, released from the
site. In both Option 1 and 2, three waste characteristics are
included in this category: contaminant toxicity, contaminant
mobility, and waste quantity. The reactivity/incompatibility factor
currently in the HRS is not included in these options. This factor
was not included in the options pending the results of a separate
analysis (DeSesso et al., 1986).
It would be desirable to include a fourth characteristic,
contaminant concentration. The incorporation of this factor is not
feasible at this time and awaits completion of an independent review
of the overall waste concentration issue.
*The probability (Pr) of the union of three independent events (A, B,
and C) is given by the following equation:
Pr(A U B U C) - Pr(A) + Pr(B) + Pr(C) - Pr(A)Pr(B) -
Pr(A)Pr(C) - Pr(fl)Pr(C) + Pr(A)Pr(B)Pr(C)
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TABLE 21
METHOD OF CALCULATING OVERALL SITE RELEASE VALUE
Descriptor
Code
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(D+
(1) x
(1) x
(2) x
(1) x
(4) -
Des. Mobility Containment
Size Value Value Sum Value Product
(A) (B) (A+B) (C) ([A+B]xC)
(2)+ (3)
(2) / 45
(3) / 45
(3) / 45
(2) x (3) /2025
(5) - (6) - (7) + (8)
Site Release Value
Note: The values of 45 and 2025 used in this method arise from the
conversion of the combined probability to a value on a scale of
0 to 45. If another scale is used, alternate values must be
developed and employed.
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The current HRS uses the single most toxic contaminant on the
site, available for migration, in assessing toxicity. Availability
is based primarily on containment considerations. If the contaminant
is not contained by a physical barrier, it is considered available.
Both options presented here envision using the single most mobile
and toxic contaminant on the site. To achieve this, a combined
toxicity-mobility evaluation approach is used. This approach weighs
toxicity and mobility nearly equally, although a slightly greater
emphasis is placed on toxicity in the evaluation. The contaminant
mobility evaluation approach used in this factor is similar to that
used in the potential-to-release mobility factor. In the release
category, however, mobilities of several contaminants were combined
to form an overall site mobility value. Here, the Individual
contaminant mobilities are used to identify and evaluate the most
toxic, most mobile contaminant.
In these options, contaminant toxicity is assessed using the
same methods as the current HRS (47 FR 31219-31243). The proposed
method can be readily modified to accommodate other methods of
assessing toxicity, such as are proposed in OeSesso et al., 1986.
Contaminant mobility is assessed as follows. If the contaminant
has been identified as being emitted from the site in an observed
release, it is assigned a mobility value of 3. If the contaminant
has not been identified as part of an observed release, its mobility
factor value is assigned differently. Mobility values for
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particulate contaminants that have not been identified as being
emitted from the site are evaluated using the particulate mobility
factor discussed previously. The assumption is made, therefore,
that the particulate mobility factor value for the overall site
applies to all particulate contaminants. The mobility value for a
nonemitted gaseous contaminant is calculated as the average of its
vapor pressure, Henry's constant and dry relative soil volatility
values according to Table 15. The mobility value for a contaminant
present as both a gas and a particle is the greater of the applicable
gas and particle mobility values. The combined toxicity-mobility
value for a particular contaminant is calculated using Table 22.
The combined toxicity-mobility value for the site is the maximum of
the combined toxicity-mobility values for the contaminants identified
on the site.
The waste quantity factor is identical to the factor in the
current HRS (47 FR 31219-31243).
The overall waste characteristics value is the sum of the
toxicity-mobility value and the waste quantity value.
4.3 Targets Category
The targets category reflects the extent of the population and
resources potentially at risk from contaminants that might be
released from the site. Three factors are included: population,
land use, and sensitive environment. The tables used to assign
values for each factor, in each option, are the same as are
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TABLE 22
COMBINED TOXICITY-MOBILITY FACTOR MATRIX
Mobility Value
0 1 _2 _3
0: 0 0 0 0
Toxicity 1: 0 2 4 6
Value 2: 2 4 8 12
3: 4 6 12 18
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currently used in the HRS (47 FR 31219-31243). The changes
envisioned in these options address the selection of location for
the center of the circles used in evaluating population, the size of
the radii of these circles, and the use of 1980 (or later, as
available) Census data to determine population. The current HRS
employs a simplistic approach to population estimation. As
discussed previously, it relies routinely on house counts in the
area surrounding the site and coverts these data into equivalent
population assuming persons per household. The number of households
is frequently derived from outdated maps of the area. The current
HRS also calculates the target distance from the location of the
wastes, or if that information is not available, from the site
boundary, using fixed target distances. This approach is illustrated
in Table 23, the current HRS air pathway population factor matrix.
If, for example, 50 people live within 1/4 mile of a site (value = 18),
while 2,000 people live within 1/2 mile of the site (value = 21), the
site would be assigned a population factor value of 21.
Improvements of this overall approach is embedded in both
options. The improvements do not address the way the population
factor is evaluated, rather they address the way the size of the
target population is determined. The options envision that the
following approach would be employed unless the local governmental
authority can provide better data. The approach is based on the
Bureau of the Census computer program, called RADII5. This publicly
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TABLE 23
CURRENT HRS TARGET POPULATION FACTOR MATRIX
Distance to Population From
Hazardous Substance (mile)
Population
1
101
1,001
3,001
10,
0
- 100
- 1,000
- 3,000
- 10,000
000+
0-4
0
9
12
15
18
21
0-1
0
12
15
18
21
24
0-1/2
0
15
18
21
24
27
0-1/4
0
18
21
24
27
30
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available computer program calculates the population reported in the
1980 Census in circles of user specified radii around any location
in the United States. Both Options 1 and 1A envision that EPA. would
acquire these programs, modify them as necessary, and provide results
to persons evaluating sites as needed.
The use of this data source would require a change in the way
target distance is calculated in the air pathway. The easiest
approach consistent with the requirements of the RADII5 program is
to employ circles of varying radii, defined in terms of an effective
source radius plus a target distance, centered at the "center of
gravity" of the site. The effective source radius is defined as
1/2 of the greatest distance between any two identifiable emissions
sources on the site.* Thus if the site contains only two
identifiable sources, the effective source radius equals 1/2 of the
distance between them. If the site contains more than two sources,
then the radius equals 1/2 of the distance between the two that are
furthest apart.
Neither of these two modifications would affect the way targets
are evaluated in the air pathway. The overall targets category
value would remain the sum of the population, land use, and
sensitive environment values in both Option 1 and 2.
*ln evaluating the distance between identifiable emission sources,
the distance should be calculated from the respective centers of
the sources.
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4.4 The Overall Pathway Score
As discussed previously, the overall pathway score is the
product of the release category, waste characteristics category
and targets category scores, normalized to a scale of 0 to 100.
The calculation of the release category score is discussed la
Section 4.1. The waste characteristics category score is the sum of
the toxicity-mobility value and the waste quantity value. Similarly,
the targets category score is the sum of the population, land use
and sensitive environment values. This approach is Illustrated in
Table 24.
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TABLE 24
METHOD OF CALCULATING AIR PATHWAY SCORE
1. OBSERVED RELEASE VALUE3
2. POTENTIAL TO RELEASE VALUEb
3. TOXICITY-MOBILITYC
4. HAZARDOUS WASTE QUANTITYd
5. WASTE CHARACTERISTICS VALUE (Lines 3+4)
6. TARGETS
7. Population
8. Land Used
9. Sensitive Environment
10. TARGETS VALUE (Lines 7+8+9)
11. If line 1 is not equal to 0.0,
multiply lines 1 x 5 x 10
If line 2 is not equal to 0.0,
multiply lines 2 x 5 x 10
12. Divide line 11 by 351 S
aFrom Worksheet 1.
^From Worksheet 2.
cFrom Worksheet 7.
dFrom HRS User's Manual.
a
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5.0 SINGLE, "WORST" SOURCE APPROACH (OPTION 2)
The principal purpose of this section is to describe a simple
mechanism for evaluating hazardous wastes sites based on their
potential to release CERCLA contaminants into the air, in the absence
of an observed release. The mechanism is closely related to the
approach described in Section 4. This simple approach is designed
to be consistent with the assumptions and approaches embodied in the
current HRS. It is designed to be implemented with a minimum of
change to the other components of the air pathway, as they currently
exist. As such, it does not address any issues in the HRS other
than the absence of a potential to release option in the current air
pathway. Alternately, this mechanism can be integrated with the
suggested revisions to the waste characteristics and targets
categories discussed in Section 4 to form another overall revision
option.
The approach described in this section follows the same general
approach as is used in the ground water and surface water pathways.
If an observed release can not be demonstrated, then the site release
category is evaluated based on the characteristics of that portion
of the site that is most likely to release contaminants to the
applicable medium. Thus, the Option 1 multiple source approach
employing probabilistic combinatorics is replaced in Option 2 by a
simpler, "worst" source approach. Additionally, in Option 2 the
list of emission source descriptors is simplified with resulting
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simplifications in the containment descriptors. Further, size is
reflected as a constraint on the selection of descriptors and does
not affect the emissions source descriptor values.
The following sections described this alternate approach to
assessing potential to release in more detail. An example of the
application of this approach to a hypothetical site is presented in
Appendix C.
5.1 The Option 2 Potential to Release Evaluation Mechanism
The approach reflected in the simplified mechanism discussed
below uses information on the physical characteristics of the site
and the waste in the site. Four site characteristics are employed
in assessing the potential of a site to emit air contaminants:
• Emission source descriptor
• Size
• Overall contaminant mobility
• Containment
The first two characteristics are reflected into a single factor,
although in a somewhat different fashion than is used in Options 1
and 1A. These characteristics are discussed in detail in
Section 4.1.2.
The overall approach to evaluating the potential of a site to
release contaminants using Option 2 is similar to that of Options 1
and 1A discussed previously. The emission sources on the site are
classified using emission source descriptors. The size of each
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emission source is also assessed. From this information, a emission
source descriptor factor value is calculated for each descriptor
meeting the applicable minimum size requirement.
Up to five contaminants present in the site are used to calculate
a gaseous contaminant mobility value for each applicable emission
source descriptor. This value is based on the average physiochemical
characteristics of the contaminants associated with each descriptor.
A particulate mobility value for the site is then calculated based on
the Thornthwaite PS Index (Thornthwaite, 1931) for the area surrounding
the site. The combined mobility value is the sum of the gaseous and
particulate mobility values. This causes the mobility factor to play
a slightly greater role, relative to the emission source descriptors,
in determining the potential to release value in Option 2 than in
Option 1.
The gas and particulate containment aspects of the area
represented by the selected descriptors are then assessed and evaluated
separately. A combined containment value is then evaluated from the
gas and particulate containment values.
The sum of the descriptor and mobility values is then multiplied
by the containment value to form the potential to release value for
the selected descriptor. This procedure is illustrated in Table 25.
The highest of the calculated descriptor factor values is taken as the
potential to release value in the air pathway for the site. Thus,
this approach employs the "worst" source in evaluating potential to
release.
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TABLE 25
ILLUSTRATION OF OPTION 2 POTENTIAL TO
RELEASE EVALUATION PROCEDURE
A) Emission Source Descriptor Value
B) Gas Mobility Value
C) Particulate Mobility Value
D) Subtotal (A + B + C)
E) Particulate Containment Value
F) Gas Containment Value
G) Combined Containment Value Maximum of
E and F
H) Emission Source Potential to Release
Value (D x G)
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5.1.1 Emission Source Descriptors
A basic list of emission source descriptors is presented in
Table C-l. The relationship between the reduced list used in this
simpler option and the original list is presented in Table 26.
The choice of emission source descriptor is left up to the
investigator evaluating the site. The restrictions to descriptor
selection are generally the same as those discussed for Options 1
and 1A (see Section 4.1.2.1). However, since the emission source
descriptor values do not vary according to size in Option 2, size is
employed as a constraint on the selection of descriptors.
Minimum size requirements were adapted from the three size
categories defined in Section 4.1.2.1. These requirements are listed
in Table 27. The size constraint imposed on the selection of
emission source descriptors in Option 2 is similar to that used in
the other options. Generally, the size of the source described by
a selected descriptor must equal or exceed the minimum listed in
Table 27, if that descriptor is to be used in evaluating the site.
The sole exception to this rule applies when this constraint can not
be met by any descriptor. In this case, the "largest" descriptor
(relative to the size requirement) is used to evaluate the site, as
in done in Options 1 and 1A.
The emission source descriptors values presented in Table 28
are adapted from the larger list of size-dependent emission source
descriptor values listed in Table 13.
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TABLE 26
OPTION 2 EMISSION SOURCE DESCRIPTORS AND DEFINITIONS
Option 2 Emission Option 1 Emission
Source Descriptor Source Descriptor
Containers Aboveground or Inground:
Tanks (All variations)
Belowground Tanks
Exposed Drum Site:
(All variations)
Contaminated Soil Contaminated Surface Soil:
(All variations)
Spill Site
Fire Site Active Fire Site
Inactive Aboveground Fire Site:
(All variations)
Inactive Belowground Fire Site:
(All variations)
Landfill Belowground Injection
Landfarm/Landtreatment
Landfill: (All variations)
Open Pit
Surface Impoundment Surface Impoundment:
(All variations)
Surface Water Body or Outfall
Waste Pile Waste Pile
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TABLE 27
OPTION 2 MINIMUM SIZE REQUIREMENTS
Descriptor
Containers
Belowground Tanks
Drum Site
Inground or Aboveground Tanks
Contaminated Soil
Fire Site
Aboveground Fire Site
Belowground Fire Site
Landfill
Surface Impoundment
Waste Pile
Minimum Size
1,000 cubic feet
1 drum
1,000 cubic feet
11,000 square feet
11,000 square feet
74,000 square feet
11,000 square feet
74,000 cubic feet
1,000 cubic feet
300 square feet
130 cubic feet
36 square feet
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TABLE 28
OPTION 2 EMISSION SOURCE DESCRIPTOR VALUES
Code Descriptors Value
01 Containers 4
02 Contaminated Soil 7
03 Fire Site 5
04 Landfill 6_
05 Surface Impoundment 8
06 Waste Pile 3
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5.1.2 Contaminant Mobility
As in Options 1 and 1A (see Section 4.1.2.2), contaminant mobility
is reflected using the combination of two mobility factors, one
addressing gaseous contaminants, the other addressing particulate
matter. The value for the gas mobility factor is determined in the
same manner as in Option 1.
The particulate mobility factor in Option 1 is based on the
equation for fugitive dust emissions from a limited particle reservoir.
Three factors were retained for tne Option 1 mechanism: erosion force,
threshold wind speed, and Thornthwaite PE Index. An analysis of the
values for the particulate mobility factor in Option 1, based on data
from randomly selected airports, indicated that the Thornthwaite PE
Index dominates the particulate mobility evaluation. Thus, a
simplified, single variable factor employing the PE index alone can be
used, sacrificing only some of the resolution provided by the more
complex approach. This simpler approach is summarized in Table 29.
The PE index for a site can be determined from Figure 2, or from the
complex equation described in Section 4.1.2.2. This simpler approach
yields nearly the same result as the more complex approach in
Option 1. The values for only 7 of the over 30 sites examined were
significantly affected by the erosion force and wind speed values.
The approach presented in Table 29 results in the same particulate
mobility factor value for all but these 7 sites, and higher values for
5 of these 7.
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TABLE 29
OPTION 2 PARTICULATE MOBILITY FACTOR
Paniculate
Thornthwaite PE Index Mobility Value
Greater than 100 0
70 to 100 1
34 to 69 2
Less than 34 3
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5.1.3 Containment
The factor value for containment is determined in Option 2 the
same way as in Option 1 (see Section 4.1.2.3). The list of Option 2
containment descriptors is also adapted from the more extensive list
prepared for Option 1. These descriptors are listed in Tables 30
and 31. The combined containment value is determined from the gas
and particulate containment values using the Option 1 approach
(Table 20).
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TABLE 30
OPTION 2 PARTICULATE CONTAINMENT FACTORS
CONTAINERS
C001P Belowground/buried containers: (see Landfill,
etc.)
C002P Intact, sealed aboveground containers;
containers protected from the weather by
a maintained cover
C003P Intact, sealed aboveground containers;
containers not protected from the weather by
a maintained cover
C004P Open, unsealed, or nonintact aboveground
container; waste totally covered with an
essentially impermeable, maintained cover
C005P Open, unsealed, or nonintact aboveground
container; waste partially covered with an
essentially impermeable, maintained cover
C006P Open, unsealed, or nonintact aboveground
container; waste totally covered with an
essentially impermeable, unmaintained cover
C007P Open, unsealed, or nonintact aboveground
container; waste otherwise covered or uncovered
C008P Aboveground containers; other
LANDFILL, CONTAMINATED SOIL, FIRE SITE, AND WASTE PILES
LD01P Site covered with an essentially Impermeable
and maintained cover or heavily vegetated
with no exposed soil or waste-bearing liquids
(e.g., paved-over)
LD02P Site substantially vegetated or totally covered
with a maintained nonwater-based dust
suppressing fluid. Little exposed soil or
waste-bearing liquids
LD03P Site lightly vegetated or partially covered
with a maintained nonwater-based dust
suppressing fluid. Much exposed soil or
waste-bearing liquids
LD04P Site substantially devoid of vegetation with
a large percentage of exposed soil or
waste-bearing liquids. No other cover
LD05P Totally enclosed in a structurally intact
building
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TABLE 30 (Concluded)
LANDFILL, CONTAMINATED SOIL, FIRE SITE, AND WASTE PILES (Concluded)
LD06P Partially enclosed in a structurally intact 2_
building
LD07P Totally enclosed in an nonintact building 2_
LD08P Partially enclosed in an nonintact building 3_
LD09P Substantially surrounded with windbreak 2_
(e.g., mesh or other fence, trees, etc.)
LD10P Active fire site 3_
LD11P Other 1
SURFACE IMPOUNDMENT
SI01P Enclosed* impoundment; impoundment totally
covered with a maintained cover
SI02P Enclosed impoundment; impoundment totally
covered with an unmaintained cover
SI03P Enclosed impoundment; impoundment partially
covered with a maintained cover
SI04P Enclosed impoundment; impoundment partially
covered with an unmaintained cover
SI05P Enclosed impoundment; uncovered, surface
completely open to atmosphere
SI06P Nonenclosed impoundment; impoundment totally
covered with a maintained cover
SI07P Nonenclosed impoundment; impoundment totally
covered with an unmaintained cover
SI08P Nonenclosed impoundment; impoundment partially
covered with a maintained cover
SI09P Nonenclosed impoundment; impoundment partially
covered with an unmaintained cover
SHOP Nonenclosed impoundment; uncovered, surface
completely open to atmosphere
SHIP Other
*An enclosed impoundment is one with a freeboard exceeding two feet
in height or one that is substantially surrounded by a wall, fence,
trees, or other adequate windbreak.
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TABLE 31
OPTION 2 GAS CONTAINMENT FACTORS
CONTAINERS
C001G
C002G
C003G
C004G
C005G
C006G
C007G
C008G
FIRE SITE
FS01G
FS02G
FS03G
FS04G
Belowground/burled containers: (see
Landfill, etc.)
Intact, sealed aboveground containers;
containers protected from the weather by
a maintained cover
Intact, sealed aboveground containers;
containers not protected from the weather by
a maintained cover
Open, unsealed, or nonintact aboveground
container; waste totally covered with an
essentially impermeable, maintained cover
Open, unsealed, or nonintact aboveground
container; waste partially covered with an
essentially Impermeable, maintained cover
Open, unsealed, or nonintact aboveground
container; waste totally covered with an
essentially impermeable, unmaintalned cover
Open, unsealed, or nonintact aboveground
container; waste otherwise covered or uncovered
Aboveground containers; other
Inactive fire site: (see Landfill, etc.)
Active aboveground fire site
Active belowground fire site: Uncontamlnated*
soil cover in excess of two feet
Active belowground fire site: Uncontamlnated*
soil cover less than two feet, soil resistant
to gas migration**
^Lacking contrary evidence, covering soils are assumed to be
uncontamlnated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL, and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
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TABLE 31 (Continued)
FIRE SITE (Concluded)
FS05G Active belowground fire site: Uncontaminated*
soil cover less than two feet, soil not
resistant to gas migration**
LANDFILL. CONTAMINATED SOIL, AND WASTE PILES
LD01G Functioning gas collection system
LD02G Existing, malfunctioning gas collection system
LD03G Intact synthetic cover plus uncontaminated soil
cover over 0.5 inches in depth*
LD04G Totally covered with an intact synthetic
cover; surface soil contaminated*
LD05G Totally covered with a nonintact synthetic
cover; surface soil contaminated*
LD06G Uncontaminated soil cover* in excess of six
inches
LD07G Uncontaminated soil cover* greater than one
inch and less than six inches; cover soil
resistant to gas migration**
LD08G Uncontaminated soil cover* less than six inches;
cover soil type unknown
LD09G Uncontaminated soil cover* greater than one
inch and less than six inches; cover soil not
resistant to gas migration**
LD10G Uncontaminated soil cover* less than one inch;
cover soil resistant to gas migration**
LD11G Uncontaminated soil cover* less than one inch;
cover soil not resistant to gas migration**
LD12G Covering soil contaminated* with waste
contaminants at surface and no synthetic
cover between surface and bulk of waste
materials
*Lacking contrary evidence, covering soils are assumed to be
uncontaminated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL, and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
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TABLE 31 (Concluded)
LANDFILL, CONTAMINATED SOIL, AND WASTE PILES (Concluded)
LD13G Totally enclosed in a structurally Intact
building
LD14G Totally enclosed in an nonintact building
LD15G Waste uncovered or exposed
LD16G Other
SURFACE IMPOUNDMENTS
SI01G Dry surface impoundment (see Landfill, etc.)
SI02G Wet enclosed* impoundment; impoundment totally
covered with a maintained, essentially
impermeable cover
SI03G Wet enclosed impoundment; impoundment totally
covered with an unmaintained, essentially
impermeable cover
SI04G Wet enclosed impoundment; impoundment partially
covered with a maintained, essentially
impermeable cover
SI05G Wet enclosed impoundment; impoundment partially
covered with an unmaintained, essentially
impermeable cover
SI06G Wet enclosed impoundment; uncovered, surface
completely open to atmosphere
SI07G Wet nonenclosed impoundment; impoundment
totally covered with a maintained, essentially
impermeable cover
SI08G Wet nonenclosed impoundment; impoundment
totally covered with an unmaintained,
essentially Impermeable cover
SI09G Wet nonenclosed impoundment; impoundment
partially covered with a maintained,
essentially impermeable cover
SI10G Wet nonenclosed impoundment; impoundment
partially covered with an unmaintained,
essentially impermeable cover
SI11G Wet nonenclosed impoundment; uncovered,
surface completely open to atmosphere
SI12G , Other
0
*An enclosed Impoundment is one with a freeboard exceeding two feet
in height or one that is substantially surrounded by a wall, fence,
trees, or other adequate windbreak.
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6.0 IMPLICATIONS
This section discusses the potential implications of adopting
the proposed revisions to the HRS air pathway. Implications for the
cost of using the HRS and the listing of sites on the National
Priorities List (NPL) are discussed. The testing and refinement of
these options is expected to reveal further issues and may resolve
some identified below.
6.1 Improvements in the HRS and the NPL
The basic purpose in revising the HRS is to improve the
capability of the HRS in identifying sites suitable for inclusion on
the National Priorities List. This purpose is achieved whenever the
scores for sites calculated using the HRS better reflect the risk
posed by the sites. Such improvements in the quality of HRS scores
serves to improve the NPL, ensuring that the sites identified as
National Priorities are the sites that should be further
investigated and, if necessary, cleaned up.
The proposed revisions to the HRS air pathway improves the HRS
in three ways. First, the revisions address the potential of a site
to release air contaminants, a characteristic currently lacking in
the HRS. The options account for many of the important factors that
determine the potential to release, although some important
characteristics of a site (e.g., age) are not included. The
important factors included in the options are the type of emission
source, size, overall contaminant mobility, and containment. As a
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result, the risks from potentially important sites at which air
monitoring was not conducted, or proved equivocal, can now be
reflected in a reasonable fashion by the HRS air route score.
Second, these options resolve a criticism of the waste
characteristics category of the current HRS. In the current system,
a very toxic contaminant can be used to assign a toxicity value,
whenever there are no physical barriers to contain it on the site,
regardless of whether that contaminant is unable to migrate due to
its chemical properties. The current approach does not address the
physiochemical characteristics of the contaminant that determine
whether it can migrate, irrespective of containment. The options
presented propose a method of assigning a value for toxicity that
includes an evaluation of the migration potential of the contaminant.
Finally, the proposed revision in the approach used in
estimating population should result in the use of more current and
accurate population estimates, improving the quality of the target
factor values.
The adoption of any of the air pathway options would also
affect the number of sites listed on the NPL. The inclusion of a
potential to release option is expected to raise the average air
pathway score since many sites that otherwise would receive a zero
air pathway score under the current riRS (those lacking an observed
release) would receive a positive score for potential to release
under the options discussed previously. Thus, if the requirement
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that the site score equal or exceed 28.50 is maintained, then a
greater number of sites would meet this requirement using the options
than would under the current HRS. This would increase the size of
the NPL.
It is not possible to determine the fraction of sites that would
be affected. However, it is possible that most if not all of the
sites that received HRS scores marginally below the cut-off (e.g.,
those scoring between 25.0 and 28.49) may qualify for listing using
the revised HRS. Table 32 provides the distribution of these
marginal sites and the air pathway scores needed to achieve the 28.50
cut-off. This table illustrates that at least 58 sites currently not
listed are potential candidates for listing using a revised HRS, if
the cut-off is not changed.
6.2 Cost Implications
The air pathway revision options were generally developed with
the intent that their adoption would not add significantly to the
costs of using the HRS. The inclusion of a potential to release
option in the air pathway requires no additional monitoring data. A
detailed site and containment description, supplemented by site
photographs, should be sufficient to evaluate the site's potential
to release. Whether this would result in an increase in site
investigation costs is problematic. However, such a cost increase
would likely be small.
107
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TABLE 32
HRS SCORING DISTRIBUTION FOR "MARGINAL" SITES
LACKING OBSERVED AIR RELEASES
Range of Maximum Points Needed Number of Sites
Current Scores To Equal or Exceed 28.5 in Given Range
25.00 - 25.49 23.67 9
25.49 - 25.00 22.05 6
26.00 - 26.49 20.19 14
26.49 - 27.00 18.19 6
27.00 - 27.49 15.79 7
27.49 - 28.00 13.01 9
28.00 - 28.49 9.20 7
Total 58
Source: Based on scores for final and proposed NPL sites that lack
observed air releases, proposed through Update 5.
108
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Further, the addition of the mobility factor in the waste
characteristics category should have a negligible cost impact as
it also requires no new data development. The recommended changes
to the targets category may result in an increase in scoring costs
as they require new data. If the RADI15 program is adopted,
appropriately modified and made available to the analysts, the cost
for providing population estimates should be no more than $100 per
site. The costs of modifying the RAD1I5 program will also be small
as the EPA Office of Air Quality Planning and Standards has already
implemented a version of the program on EPA's computer. Thus, the
only potentially significant program cost increase that might arise
from incorporating the air revision is the additional analyst costs.
This cost should not exceed the equivalent of 8 person-hours per
site. These costs may be minimized by developing tables that would
facilitate scoring, eliminating some of the worksheets described in
the appendices.
6.3 Potential Implications for Other HRS Pathways
Some of the changes to the air pathway envisioned in these
options raise issues for the ground water and surface water pathways,
In general, if the HRS is to remain internally consistent, should
the other pathways be revised in the same fashion as suggested for
the air pathway? For example, should the potential to release
options currently employed in the other pathways be revised to
reflect the presence of multiple potential sources using an approach
109
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based on probabilistic combinatorics? The following aspects of the
revisions are of particular importance in this context:
• Criteria for observed release
• Use of multiple descriptors
• Probabilistic scoring algorithm
• Use of Census data in targets category
• Combined toxicity-mobility factor
• Multi-contaminant mobility factor in potential to release
The nature and extent of changes in the other pathways that might
arise from adoption of the air pathway options are unknown.
110
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7.0 SUMMARY AND CONCLUSIONS
This paper has presented three options for revising the HRS air
pathway. The suggested revisions include a potential to release
option in the release category, a combined toxicity-mobility factor
in the waste characteristics category, and revisions in the target
distance and population estimation procedures in the targets
category. Adoption of the suggested revisions would improve the HRS
and the NPL by increasing the degree to which HRS scores reflect the
potential risks from hazardous wastes sites and, as a result, by
providing better discrimination among potential NPL sites.
Since these options would constitute an improvement in the HRS,
one of the options should be proposed, as modified after testing, as
a formal revision to the HRS in the National Contingency Plan. Of
the options, Option 1 is preferred. This option employs more
descriptors and should, therefore, provide greater discrimination
among sites. Option 2 is simpler, consistent with the approach used
in the other pathways, and would be an adequate procedure for
evaluating potential to release. However, the use of Option 2 would
discriminate against sites with multiple sources. Hence, it would
understate the potential for such sites to release contaminants and
would thus understate their relative risks. Regardless, if Option 2
were adopted, the adoption of the recommended changes to the waste
characteristic category and targets estimation procedures would be
indicated.
Ill
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8.0 REFERENCES AND BIBLIOGRAPHY
8.1 Selected References on Emission Processes
Anderson, David C. and Stephen G. Jones, "Fate of Organic Liquids on
Soil," Proceedings of the National Conference and Exhibition on
Hazardous Waste and Environmental Emergencies, Held on March 12-14,
1984 in Houston, TX, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1984, pp. 384-388.
Bennett, Gary F. "Fate of Solvents in a Landfill," Proceedings of
the National Conference on Hazardous Wastes and Environmental
Emergencies, Held on May 14-16, 1985 in Cincinnati, OH, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1985,
pp. 199-210.
Brown, Kirk W., Gordon B. Evans, Jr., and Beth D. Frentrup, eds.,
Hazardous Waste Land Treatment, Butterworth Publishers, Woburn, MA,
1983.
Cowherd, Chatten Jr. et al., Rapid Assessment of Exposure to
Particulate Emissions from Surface Contamination Sites, Midwest
Research Institute, Kansas City, MO, September 1984.
Hwang, Seong T., "Toxic Emissions from Land Disposal Facilities,"
Environmental Progress, Vol. 1, No. 1, February 1982, pp. 46-52.
James, S. C., R. N. Kinman, and D. L. Nutini, "Toxic and Flammable
Gases," Contaminated Land; Reclamation and Treatment, Michael A.
Smith, ed., Plenum Press, New York, NY, 1985.
Kinman, Riley N. and David L. Nutini, "Production, Migration, and
Hazards Associated with Toxic and Flammable Gases at Uncontrolled
Hazardous Waste Sites," Land Disposal of Hazardous Waste:
Proceedings of the Tenth Annual Research Symposium, (EPA-600/
9-84-007), U.S. Environmental Protection Agency, Cincinnati, OH,
August 1984, pp. 52-60.
Shen, Thomas T., "Air Quality Assessment for Land Disposal of
Industrial Wastes," Environmental Management, Vol. 6, No. 4, 1982,
pp. 297-305.
Shen, Thomas T., "Estimating Hazardous Air Emissions from Disposal
Sites," Pollution Engineering, Vol. 13, No. 8, August 1981,
pp. 31-371
Shen, Thomas T., "Estimation of Organic Compound Emissions from
Waste Lagoons," Journal of the Air Pollution Control Association,
Vol. 32, No. 1, January 1982, pp. 79-82.
113
-------
Shen, Thomas T. and Granvllle H. Sewell, "Air Pollution Problema of
Uncontrolled Hazardous Waste Sites," Proceedings of the National
Conference on Management of Uncontrolled Hazardous Waste Sites, Held
on November 29-December 1, 1982 In Washington, DC, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1982,
pp. 76-80.
Shen, Thomas T. and James Tofflemire, "Air Pollution Aspects of Land
Disposal of Toxic Waste," Journal of the Environmental Engineering
Division of ASCE, Vol. 106, No. EE1, February 1980, pp. 211-226.
Thibodeaux, Louis J., "Estimating The Air Emissions of Chemicals
from Hazardous Waste Landfills," Journal of Hazardous Materials,
Vol. 4, 1981, pp. 235-244.
8.2 Selected References Addressing Air Monitoring Guidance
Ford, P. J., P. J. Turlna, and D. E. Seeley, Characterization of
Hazardous Sites, A Methods Manual. Volume 2. Available Sampling
Methods, (EPA-600/4-83-040), U.S. Environmental Protection Agency.
Las Vegas, NV, September 1983.
Hanlsch, Robert C. and Maureen A. McDevitt, Protocols for Sampling
and Analysis of Surface Impoundments and Land Treatment/Disposal
Sites for VOCs: Technical Note, (DCN 84-222-078-11-12), Radian
Corporation, Austin, TX, September 28, 1984.
Plumb, R. H., Jr., Characterization of Hazardous Sites, A Methods
Manual. Volume 3. Available Laboratory Analytical Methods,
(EPA-600/4-84-038), U.S. Environmental Protection Agency, Las Vegas,
NV, May 1984.
Rlggin, R. M., Compendium of Methods for the Determination of Toxic
Organic Compounds in Ambient Air, (EPA-600/4-84-041), U.S.
Environmental Protection Agency, Research Triangle Park, NC,
April 1984.
U.S. Environmental Protection Agency, Field Standard Operating
Procedures for Air Surveillance F.S.O.F. 8, (Draft), U.S.
Environmental Protection Agency, Environmental Response Team,
Washington, DC, 1985.
U.S. Environmental Protection Agency, Standard Operating Safety
Guides, U.S. Environmental Protection Agency, Washington, DC,
November 1984.
114
-------
U.S. Environmental Protection Agency, Technical Assistance for
Sampling and Analysis of Toxic Organic Compounds in Ambient Air,
CEPA-600/ 4-83-027), U.S. Environmental Protection Agency, Research
Triangle Park, NC, 1983.
8.3 Principal References Used in Developing Containment Factors
Brown, D. et al., Techniques for Handling Landborne Spills of
Volatile Hazardous' Substances, (EPA-600/ 2-81-207), U.S.
Environmental Protection Agency, Cincinnati, OH, September 1981.
Brown, Kirk W. , Gordon B. Evans, Jr., and Beth D. Frentrup, eds.,
Hazardous Waste Land Treatment, Butterworth Publishers, Woburn, MA,
Ehrenfeld, John R. and Joo Hooi Ong, Evaluation of Emission Controls
for Hazardous Waste Treatment, Storage, and Disposal Facilities,
(EPA-450/ 3-84-017), U.S. Environmental Protection Agency, Research
Triangle Park, NC, November 1984.
Ehrenfeld, John R. and Joo Hooi Ong, "Control of Emissions from
Hazardous Waste Treatment Facilities," (85-70.1), Presented at the
78th Annual Meeting of the Air Pollution Control Association, Held
on June 16-21, 1985 in Detroit, MI, Air Pollution Control
Association, Pittsburgh, PA, 1985.
Farmer, Walter J. et al., Land Disposal of Hexachlorobenzene Waste -
Controlling Vapor Movement in Soil, (EPA-600/2-80-119) , U.S.
Environmental Protection Agency, Cincinnati, OH, August 1980.
Genetelli, Emil J. and John Cirello, eds., Gas and Leachate from
Landfills; Formation, Collection and Treatment, (EPA-600/ 9-76-004)
U.S. Environmental Protection Agency, Cincinnati, OH, 1976.
James, S. C. , R. N. Kinman, and D. L. Nutini, "Toxic and Flammable
Gases," Contaminated Land; Reclamation and Treatment, Michael A.
Smith, ed., Plenum Press, New York, NY, 1985.
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
Lutton, R. J., G. L. Regan, and L. W. Jones, Design and Construction
of Covers for Solid Waste Landfills, (EPA-600/ 2- 79-165), U.S.
Environmental Protection Agency, Cincinnati, OH, 1979.
Moore, Charles A., "Landfill Gas Generation, Migration and Controls,"
CRC Critical Reviews in Environmental Control, Vol. 9, No. 2,
November 1979, pp. 157-184.
115
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Patry, G. D. R. and R. M. Bell, "Covering Systems," Contaminated
^aud; Reclamation and Treatment, Michael A. Smith, ed.,
Plenum Press, New York, NY, 1985.
Roabury, Keith D. and Stephen C. James, "The Control of Fugitive
Dust Emissions at Hazardous Waste Cleanup Sites," Proceedings of the
Fifth National Conference on Management of Uncontrolled Hazardous
Waste Sites, Held on November 7-9, 1984 in Washington, DC, Hazardous
Materials Control Research Institute, Silver Spring, MD, 198A,
pp. 265-267.
Ihibodeaux, Louis J., Charles Springer, and Rebecca S. Parker,
"Design for Control of Volatile Chemical Emissions from Surface
Impoundments," Hazardous Waste and Hazardous Materials, Vol. 2,
No. 1, 1985, pp. 99-106.
Vogel, Gregory A. and Denis F. 0'Sullivan, Air Emission Control
Practices at Hazardous Waste Management Facilities, (MTR-83W89),
The MITRE Corporation, McLean, VA7 June 1983.
Walsh, Gary, "Control of Volatile Air Emissions from Hazardous Waste
Land Disposal Facilities," Proceedings of the National Conference on
Hazardous Wastes and Environmental Emergencies, Held on May 12-14,
1984 in Houston, TX, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1984, pp. 146-153.
8.4 General Bibliography
Amoore, John E. and Earl Hautala, "Odor as an Aid to Chemical Safety:
Odor Thresholds Compared with Threshold Limit Values and Volatilities
for 214 Industrial Chemicals in Air and Water Dilution," Journal of
Applied Toxicology, Vol. 3, No. 6, 1983, pp. 272-290.
Amster, Michael B., Nasrat Hijazi, and Rosalind Chan, "Real Time
Monitoring of Low Level Air Contaminants from Hazardous Waste Sites,"
Proceedings of the National Conference on Management of Uncontrolled
Hazardous Waste Sites, Held on October 31-November 2, 1983 in
Washington, DC, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1983, pp. 98-99.
Anderson, David C. and Stephen G. Jones, "Fate of Organic Liquids on
Soil," Proceedings of the National Conference and Exhibition on
Hazardous Waste and Environmental Emergencies, Held on March 12-14,
1984 in Houston, TX, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1984, pp. 384-388.
Arthur D. Little, Inc., Proposed Revisions to MITRE Model,
Arthur D. Little, Inc., Cambridge, MA, September 23, 1981.
116
-------
Arthur D. Little, Inc., An Analysis of the Hazard Ranking System and
the National Priority List. (Reference No. 88922), Arthur D. Little,
Inc., Cambridge, MA, February 1983.
Astle, Alice D., Richard A. Duffee, and Alexander R. Stankuas,
Ph.D., "Estimating Vapor and Emission Rates from Hazardous Waste
Sites," Proceedings of the National Conference on Management of
Uncontrolled Hazardous Waste Sites, Held on November 29-December 1,
1982 in Washington, DC, Hazardous Materials Control Research
Institute, Silver Spring, MD, 1982, pp. 326-330.
Baker, Lynton W., An Evaluation of Screening Models for Assessing
Toxic Air Pollution Downwind of Hazardous Waste Landfills, Masters
Thesis, Office of Graduate Studies and Research, San Jose State
University, San Jose, CA, May 1985.
Baker/TSA, Tyson's Dump Site, Montgomery County, PA, Draft Remedial
Investigation Report, Baker/ISA, Beaver, PA, August 1984.
Balfour, W. David and Charles E. Schmidt, Sampling Approaches for
Measuring Emission Rates from Hazardous Waste Disposal Facilities,
(EPA-600/D-84-140), U.S. Environmental Protection Agency, Cincinnati,
OH, May 1984.
Balfour, W. D., R. G. Wetherold, and D. L. Lewis, Evaluation of Air
Emissions from Hazardous Waste Treatment, Storage, and Disposal
Facilities, (EPA-600/2-85-057), U.S. Environmental Protection
Agency, Cincinnati, OH, May 1985.
Balfour, W. D. et al., "Field Verification of Air Emission Models
for Hazardous Waste Disposal Facilities," Land Disposal of Hazardous
Waste; Proceedings of the Tenth Annual Research Symposium, (EPA-600/
9-84-007), U.S. Environmental Protection Agency, Cincinnati, OH,
August 1984, p. 197.
Battye, William et al., Preliminary Source Assessment for Hazardous
Waste Air Emissions from Treatment, Storage and Disposal Facilities
(TSDFs), (Draft Final Report), GCA Corporation, Bedford, MA,
February 1985.
Bell, R. M. and G. D. R. Parry, "The Upward Migration of Contaminants
Through Covering Systems," Proceedings of the Fifth National
Conference on Management oflJncontrolled Hazardous Waste Sites, Held
on November 7-9, 1984 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1984, pp. 588-591.
117
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Bennett, Gary F., "Fate of Solvents in a Landfill," Proceedings of
the National Conference on Hazardous Wastes and Environmental
Emergencies, Held on May 14-16, 1985 in Cincinnati, OH, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1985,
pp. 199-210.
Bilsky, I. L., "Air Pollution Aspects of Hazardous Waste Disposal in
Texas," (85-79.3), Presented at the 78th Annual Meeting of the Air
Pollution Control Association, Held on June 16-21, 1985 in Detroit,
MI, Air Pollution Control Association, Pittsburgh, PA, 1985.
Bradstreet, Jeffrey W., Richard A. Duffee, and James J. Zoldak,
"Quantification of Odors from Waste Sites," (85-79.4), Presented at
the 78th Annual Meeting of the Air Pollution Control Association,
Held on June 16-21, 1985 in Detroit, MI, Air Pollution Control
Association, Pittsburgh, PA, 1985.
Breton, Marc et al., Assessment of Air Emissions from Hazardous
Waste Treatment, Storage, and Disposal Facilities (TSDFs) -
Preliminary National Emissions Estimates, (Draft Final Report),
(GCA-TR-83-70-G), GCA Corporation, Bedford, MA, August 1983.
Breton, Marc et al., Evaluation and Selection of Models for
Estimating Air Emissions from Hazardous Waste Treatment, Storage,
and Disposal Facilities, (FJPA-450/3-84-020), U.S. Environmental
Protection Agency, Research Triangle Park, NC, December 1984.
Brodzinsky, Richard and Hanwant B. Singh, Volatile Organic Chemicals
in the Atmosphere; An Assessment of Available Data, (EPA-600/
3-83-027a), U.S. Environmental Protection Agency, Research Triangle
Park, April 1983.
Brown, D. et al., Techniques for Handling Landborne Spills of
Volatile Hazardous Substances, (EPA-bOO/2-81-207), U.S. Environmental
Protection Agency, Cincinnati, OH, September 1981.
Brown, Kirk W., Gordon B. Evans, Jr., and Beth D. Frentrup, eds.,
Hazardous Waste Land Treatment, Butterworth Publishers, Woburn, MA,
TSBT:
Brown, Richard D., Hazard Ranking System Issue Analysis; Use of
Significance in Determining Observed Release, (MTR-86W101), The
MITRE Corporation, McLean, VA, July 1986.
Burkuard, Lawrence P., Anders W. Andren, and David K. Armstrong,
"Estimation of Vapor Pressures for Polychlorinated Biphenyls: A
Comparison of Eleven Predictive Methods," Environmental Science and
Technology, Vol. 19, No. 6, 1985a, pp. 50CPW1: ~~
118
-------
Burkhard, Lawrence P., Anders W. Andren, and David E. Armstrong,
"Henry's Law Constants for the Polychlorinated Biphenyls,"
Environmental Science and Technology, Vol. 19, No. 7, 1985b,
pp. 590-596.
Caldwell, Steve, Kris W. Barrett, and S. Steven Chang, "Ranking
System for Releases of Hazardous Substances," Proceedings of the
National Conference on Management of Uncontrolled Hazardous Waste
Sites, Held on October 28-30, 1981 in Washington, DC, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1981,
pp. 14-20.
Caravanos, Jack and Thomas T. Shen, "The Effect of Wind Speed on the
Emission Rates of Volatile Chemicals from Open Hazardous Waste Dump
Sites," Proceedings of the Fifth National Conference on Management
of Uncontrolled Hazardous Waste Sites, Held on November 7-9, 1984 in
Washington, DC, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1984, pp. 68-71.
Caravanos, Jack, Granville H. Sewell, and Thomas T. Shen, "Validation
of Mathematical Models Predicting the Airborne Chemical Emission
Rates from Saturated Soils," (85-73.4), Presented at the 78th Annual
Meeting of the Air Pollution Control Association, Held on June 16-21,
1985 in Detroit, MI, Air Pollution Control Association, Pittsburgh,
PA, 1985.
CH2M Hill, Ecology and Environment, Draft Remedial Investigation
Report, Mid-State Disposal Site, Stratford, Wisconsin, CH2M Hill,
Reston, VA, July 8, 1905.
CH2M Hill, Ecology and Environment, Final Remedial Investigation
Report, City of Coshocton Landfill, Coshocton, Ohio, CH2M Hill,
Reston, VA, May 24, 198b.
CH2M Hill, Ecology and Environment, Remedial Investigation Report;
Bayou Sorrel, Louisiana, Draft, Volume 1, CH2M Hill, Reston, VA,
July 12, 1965.
CH2M Hill, Ecology and Environment, Remedial Investigation Report;
Volume 1 of 2, Cleve Reber Site Ascension Parish, Louisiana, CH2M
Hill, Reston, VA, May 30, 1905.
Chang, S. and R. Holberger, National Priority List Technical Data
Base, (WP-83W239), The MITRE Corporation, McLean, VA, May 1983.
Chiou, Gary T., David W. Schmedding, and Milton Manes, "Partitioning
of Organic Compounds in Octanol-Water Systems," Environmental Science
and Technology, Vol. 16, No. 1, 1982, pp. 4-10.
119
-------
Clement Associates, Inc., The Risk Assessment Procedure as Applied
to Hazardous Waste Sites; An Introductory Manual, Clement
Associates, Inc. Washington, DC, August 5, 1980.
Committee on Appropriations, U.S. Senate, Selection of Hazardous
Waste Sites for Superfund Funding; Workshop, U.S. Government
Printing Office, Washington, DC, 1982.
Committee on Finance, U.S. Senate, Superfund Issues; Hearings,
September 19 and 21, 1984, U.S. Government Printing Office,
Washington, DC,
Conway, R. A., ed., Environmental Risk Analysis for Chemicals,
Van Nostrand Reinhold Co., New York, NY, 1982.
Cowherd, Chatten, Jr., "Measurement of Fartlculate Emissions from
Hazardous Waste Disposal Sites," (85-73.3), Presented at the 78th
Annual Meeting of the Air Pollution Control Association, Held on
June 16-21, 1985 in Detroit, MI, Air Pollution Control Association,
Pittsburgh, PA, 1985.
Cowherd, Chatten Jr. et al., Rapid Assessment of Exposure to
Particulate Emissions From Surface Contamination Sites, (EPA-600/
8-85-002), U.S. Environmental Protection Agency, Washington, DC,
February 1985.
Cox, Geraldine V., David F. Zoll, and Richard G. Stoll, Jr., CMA's
Comments on the Proposed Revisions to the National Contingency Plan,
Chemical Manufacturers Association, Washington, DC, April 28, 1982.
Cupitt, Larry T. , Fate of Toxic and Hazardous Materials in the Air
Environment, (EPA-600/ 3-80-084 ), U.S. Environmental Protection
Agency, Research Triangle Park, NC, August 1980.
D'Appolonia/GDC, Final Report Remedial Investigation Phase One -
Element I, Old Inger Abandoned Hazardous Waste Site, Darrow,
Louisiana, D'Appolonia/GDC, Baton Rouge, LA, October 1982.
Davidson, J. M. et al., Adsorption, Movement, and Biological
Degradation of Large Concentrations of Selected Pesticides in Soils,
(EPA-600/ 2-80-124)7 U.S. Environmental Protection Agency, Cincinnati,
OH, August 1980.
DeSesso, John et al., Hazard Ranking System Issue Analysis; Toiicity
as a Ranking Factor, (MTR-86W128) , The MITRE Corporation, McLean, VA,
September 1986.
120
-------
Drivas, P. "Calculation of Evaporative Emissions from Multicomponent
Liquid Spills," Environmental Science and Technology, Vol. 16,
No. 10, October 1982, pp. 726-728.
Durham, James P., "Quantification of Atmospheric Emissions from
Hazardous Waste Sites: A Status Report," Presented at the 78th
Annual Meeting of the Air Pollution Control Association, Held on
June 16-21, 1985 in Detroit, MI, Air Pollution Control Association,
Pittsburgh, PA, 1985.
Dynamac Corp., Methods for Assessing Exposure to Windblown
Particulates, (EPA-600/4-83-007), uTs. Environmental Protection
Agency, Washington, DC, March 1983.
Eckel, William P, Donald P. Trees, and Stanley P. Kovell,
"Distribution and Concentration of Chemicals and Toxic Materials
Found at Hazardous Waste Dump Sites," Proceedings of the National
Conference on Hazardous Wastes and Environmental Emergencies, Held
on May 14-16, 1985 in Cincinnati, OH, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1985, pp. 250-257.
Ehrenfeld, John and Jeffrey Bass, Handbook for Evaluating Remedial
Action Technology Plans, (EPA-600/2-83-076), U.S. Environmental
Protection Agency, Washington, DC, August 1983.
Ehrenfeld, John R. and Joo Hooi Ong, Evaluation of Emission Controls
for Hazardous Waste Treatment, Storage, and Disposal Facilities,
(EPA-450/3-84-017), U.S. Environmental Protection Agency, Research
Triangle Park, NC, November 1984.
Ehrenfeld, John R. and Joo Hooi Ong, "Control of Emissions from
Hazardous Waste Treatment Facilities," (85-70.1), Presented at the
78th Annual Meeting of the Air Pollution Control Association, Held
on June 16-21, 1985 in Detroit, MI, Air Pollution Control
Association, Pittsburgh, PA, 1985.
Environmental Law Institute, Economic Analysis and Risk Management;
An Application to Hazardous Wastes, (EPA-600/2-82/001), U.S.
Environmental Protection Agency, Washington, DC, January 1984.
Ess, Terry and Chia Shun Shih, "Perspectives of Risk Assessment for
Uncontrolled Hazardous Waste Sites," Proceedings of the National
Conference on Management of Uncontrolled Hazardous Waste Sites,
Held on November 29-December 1, 1982 in Washington, DC, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1982,
pp. 390-395.
121
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Falco, James W., Lee A. Mulkey, and John Schaum, "Multimedia Modeling
of Transport and Transformation of Contaminants," Environment and
Solid Wastes Characterization, Treatment and Disposal, Francis, C. W.
and S. E. Auerbach, eds., Proceedings of the Fourth Life Sciences
Symposium, Environment and Solid Wastes, Held on October 4-8, 1981
in Gatlinburg, TN, Butterworth Publishers, Woburn, MA, 1983,
pp. 223-238.
Farmer, Walter J. et al., Land Disposal of Hexachlorobenzene Waste -
Controlling Vapor Movement in Soil, (EPA-6QO/2-80-119), U.S.
Environmental Protection Agency, Cincinnati, OH, August 1980.
Fellows, Charles R. and James H. Sullivan, "Refined Strategies for
Abandoned Site Discovery and Assessment," Proceedings of the National
Conference on Management of Uncontrolled Hazardous Waste Sites, Held
on October 31-November 2, 1983 in Washington, DC, Hazardous Materials
Control Research Institute, Silver Spring, MD, 1983, pp. 37-42.
Flynn, Norman W. et al., Trace-Chemical Characterization of
Pollutants Occurring in the Production of Landfill Gas from Shoreline
Regional Park Sanitary Landfill, Mountain View, California,
(DOE/CS/20291—2), U.S. Department of Energy, Washington, DC,
October 1982.
Ford, Karl L. and Paul Gurba, "Methods of Determining Relative
Contaminant Mobilities and Migration Pathways Using Physical-Chemical
Data," Proceedings of the Fifth National Conference on Management of
Uncontrolled Hazardous Waste Sites, Held on November 7-9, 1984 in
Washington, DC, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1984, pp. 210-212.
Ford, P. J., P. J. Turina, and D. E. Seeley, Characterization of
Hazardous Sites, A Methods Manual. Volume 2. Available Sampling
Methods, (EPA-60Q/4-83-040). U.S. Environmental Protection Agency.
Las Vegas, NV, September 1983.
Francis, Chester W., Stanley I. Auerbach, and Vivian A. Jacobs,
eds., Environment and Solid Wastes Characterization, Treatment and
Disposal, Proceedings of the Fourth Life Sciences Symposium,
Environment and Solid Wastes, Held on October 4-8, 1981 in
Gatlinburg, TN, Butterworth Publishers, Woburn, MA, 1983.
Friedman, Paul H. et al., "Construction of a Data Base from Hazardous
Waste Site Chemical Analyses," Proceedings of the Fifth National
Conference on Management of Uncontrolled Hazardous Waste Sites, Held
on November 7-9, 1984 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1984, pp. 49-52.
122
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Genetelli, Emil J. and John Cirello, eds., Gas and Leachate from
Landfills; Formation, Collection and Treatment, (EPA-600/9-76-004)
U.S. Environmental Protection Agency, Cincinnati, OH, 1976.
Hanisch, Robert C. and Maureen A. McDevitt, "Protocols for Sampling
and Analysis of Surface Impoundments and Land Treatment/Disposal
Sites for VOCs," (85-73.1), Presented at the 78th Annual Meeting of
the Air Pollution Control Association, Held on June 16-21, 1985 in
Detroit, MI, Air Pollution Control Association, Pittsburgh, PA, 1985.
Hanisch, Robert C. and Maureen A. McDevitt, Protocols for Sampling
and Analysis of Surface Impoundments and Land Treatment/Disposal
Sites for VOCs; Technical Note, QDCN 84-222-078-11-12), Radian
Corporation, Austin, IX, September 28, 1984.
Hanna, Steven B., Gary A. Briggs, and Rayford P. Hosker, Jr.,
Handbook on Atmospheric Diffusion, (DE82002045), U.S. Department of
Energy, Washington, DC, 1982.
Hazardous Materials Control Research Institute et al., Proceedings
of the National Conference on Hazardous Wastes and Environmental
Emergencies, Held on May 12-14, 1984 in Houston, TX, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1984.
Hazardous Materials Control Research Institute et al., Proceedings
of the National Conference on Hazardous Wastes and Environmental
Emergencies, Held on May 14-16, 1985 in Cincinnati, OH, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1985.
Horgan, Liam, Daniel Lillian, and Peter Franconeri, "Determining
Volatile Organic Vapor Emissions from Hazardous Waste Sites,"
Presented at the American Institute of Chemical Engineers, 1984
Summer National Meeting, Philadelphia, PA, August 19-21, 1984.
Hunt, Gary T. and Bruce A. Egan, "Air Toxics Update," Pollution
Engineering, Vol. XVII, No. 6, June 1985, pp. 46-52.
Hwang, Seong T., "Model Prediction of Volatile Emissions,"
Environmental Progress, Vol. 4, No. 2, May 1985, pp. 141-144.
Hwang, Seong T., "Toxic Emissions from Land Disposal Facilities,"
Environmental Progress, Vol. 1, No. 1, February 1982, pp. 46-52.
Hwang, Seong T. and Louis J. Thibodeaux, "Measuring Volatile
Chemical Emission Rates from Large Waste Disposal Facilities,"
Environmental Progress, Vol. 2, No. 2, May 1983, pp. 81-86.
123
-------
IMS Engineers - Architects, P. C., Remedial Investigation -
Feasibility Study, Moyer Landfill Site, Collegeville, Pennsylvania,
Volume 1, IMS Engineers - Architects, P. C., Rochester, NY,
July 16, 1985.
Iverson, Christine et al., Site Assessment System (SAS) for the
Michigan Priority Ranking System under the Michigan Environmental
Response Act (Act 307, P"A. 1982), Michigan Department of Natural
Resources, Lansing, MI, November 1983.
James, S. C., R. N. Kinman, and D. L. Nutini, "Toxic and Flammable
Gasv-s," Contaminated Land; Reclamation and Treatment, Michael A.
Smith, ed., Plenum Press, New York, NY, 1985.
Jarke, Frank H., "Odorous Emissions from Waste Disposal Sites
Owner/Operator Concerns," (85-79.1), Presented at the 78th Annual
Meeting of the Air Pollution Control Association, Held on June 16-21,
1985 in Detroit, MI, Air Pollution Control Association, Pittsburgh,
PA, 1985.
Jaynes, E. T., "Probability Theory in Science and Engineering,"
Colloquium Lectures in Pure and Applied Science, No. 4, Field
Research Laboratory, Socony Mobil Oil Co., Inc., February 1958.
JRB Associates, Guidance on Remedial Investigations Under CERCLA,
(EPA-540/G-85-002), U.S. Environmental Protection Agency,
Cincinnati, OH, June 1985.
Jubach, Robert W. et al., "An Atmospheric Field Program Conducted at
a Hazardous Waste Site," (85-69.3), Presented at the 78th Annual
Meeting of the Air Pollution Control Association, Held on June 16-21,
1985 in Detroit, MI, Air Pollution Control Association, Pittsburgh,
PA, 1985.
Kelly, Kathryn E., "Comparisons of Metals Emissions Data From
Hazardous Waste Incineration Facilities," (85-72.8), Presented at
the 78th Annual Meeting of the Air Pollution Control Association,
Held on June 16-21, 1985 in Detroit, MI, Air Pollution Control
Association, Pittsburgh, PA, 1985.
Kim, C. Stephen et al., "Love Canal: Chemical Contamination and
Migration," Proceedings of the National Conference on Management of
Uncontrolled Hazardous Waste Sites, Held on October 15-17. 1980 in
Washington, DC, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1980, pp. 212-219.
124
-------
Kinman, Riley N. and David L. Nutini, "Production, Migration, and
Hazards Associated with Toxic and Flammable Gases at Uncontrolled
Hazardous Waste Sites," Land Disposal of Hazardous Waste;
Proceedings of the Tenth Annual Research Symposium, (EPA-600/
9-84-007)7 U.S. Environmental Protection Agency, Cincinnati, OH,
August 1984, pp. 52-60.
Klee, Albert J. and Michael U. Flanders, "Classification of
Hazardous Wastes," Journal of the Environmental Engineering
Division, Proceedings of the American Society of Civil Engineers,
Vol. 106, No. EE1, February 1980, pp. 163-175.
Kyberg, Henry E. and Howard E. Smokier, Studies in Subjective
Probability, John Wiley and Sons, New York, NY, 1964.
LaRegina, J. E. et al., "Volatile Organic Compounds at Hazardous
Waste Sites and Sanitary Landfills in New Jersey," Presented at the
American Institute of Chemical Engineers, 1984 Summer National
Meeting, Philadelphia, PA, August 19-21, 1984.
Leo, Albert, Corwin Hansch, and David Elkins, "Partition
Coefficients and Their Uses," Chemical Reviews, Vol. 71, No. 6,
December 1971, pp. 525-616.
Lipsky, David, "Buried Waste Characterization Using Air Monitoring
Instrumentation," Proceedings of the National Conference on
Environmental Engineering, sponsored by the Environmental Engineering
Division, ASCE, Boulder, CO, July 6-8, 1983.
Lipsky, David and Brian Jacot, "Hazardous Emissions from Sanitary
Landfills," (85-69.4), Presented at the 78th Annual Meeting of the
Air Pollution Control Association, Held on June 16-21, 1985 in
Detroit, MI, Air Pollution Control Association, Pittsburgh, PA, 1985.
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
Lutton, R. J., G. L. Regan, and L. W. Jones, Design and Construction
of Covers for Solid Waste Landfills, (EPA-600/2-79-165), U.S.
Environmental Protection Agency, Cincinnati, OH, 1979.
Lytwynsyshyn, G. R et al., Landfill Methane Recovery Part II; Gas
Characterization, Final Report, (ANL/CNSV-TM-118). Argonne National
Laboratory, Argonne, IL, December 1982.
Mackay, Donald, "Environmental and Laboratory Rates of Volatilization
of Toxic Chemicals from Water," Hazard Assessment of Chemicals, I,
1981, pp. 303-322. —
125
-------
Mackay, Donald and Yoram Cohen, "Prediction of the Volatilization
Rate of Pollutants in Aqueous Systems," Presented at the National
Bureau of Standards Symposium on Non-biological Transport and
Transformations of Pollutants on Land and Water, National Bureau of
Standards, Gaithersburg, MD, May 1976.
Mackay, Donald and Andrew T. K. Yeun, "Mass Transfer Coefficient
Correlations for Volatilization of Organic Solutes from Water,"
Environmental Research and Technology, Vol. 17, No. 4, April 1983,
pp. 211-217.
Mackay, Donald, "Finding Fugacity Feasible," Environmental Research
and Technology, Vol. 13, No. 10, October 1979, pp. 1218-1223.
Mackay, Donald and Paul J. Leinonen, "Rate of Evaporation of
Low-Solubility Contaminants from Water Bodies to Atmosphere,"
Environmental Science and Technology, Vol. 9, No. 13,
December 1975, pp. 1178-1180.
Mackay, Donald and Sally Paterson, "Calculating Fugacity,"
Environmental Research and Technology, Vol. 15, No. 9,
September 1981, pp. 1006-1014.
Mackay, Donald and Sally Paterson, "Fugacity Revisited,"
Environmental Research and Technology, Vol. 16, No. 12,
December 1982, pp. 654A-660A.
Mackay, Donald and Sally Paterson, "Spatial Concentration
Distributions," Environmental Research and Technology, Vol. 18,
No. 7, July 1984, pp. 207A-214A.
Mackay, Donald et al., "Vapor Pressure Correlations for
Low-Volatility Environmental Chemicals," Environmental Science and
Technology, Vol. 16, No. 10, 1982, pp. 645-649.
Mayer, R., J. Letey, and W. J. Farmer, "Models for Predicting
Volatilization of Soil-Incorporated Pesticides," Soil Sci. Soc.
Amer. Proc., Vol. 38, No. 4, 1974, pp. 563-568.
McClure, Vance E., "Transport of Heavy Chlorinated Hydrocarbons in
the Atmosphere," Environmental Science and Technology, Vol. 10,
No. 13, December 1976, pp. 1223-1229.
McCord, Andrew T., "A Study of the Emission Rate of Volatile
Compounds from Lagoons," Proceedings of the National Conference
on Management of Uncontrolled Hazardous Waste Sites, Held on
October 28-30, 1981 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1981, pp. 129-135.
126
-------
Michigan Department of Natural Resources, Evaluation of the MITRE
Model as a Prioritization Method for Ranking Hazardous Waste Sites,
Michigan Department of Natural Resources, Lansing, MI, 1982.
Michigan Department of Natural Resources, Michigan Air Priority
Chemicals List, 1980, Michigan Department of Natural Resources,
Lansing, MI, 1980.
Miller, John M., ed., The Potential Atmospheric Impact of Chemicals
Released to the Environment; Proceedings of Four Workshops,
(EPA-560/5-80-001), U.S. Environmental Protection Agency,
Washington, DC, 1981.
Miller, Joseph J. and Mark B. Beizer, "Air Quality in Residences
Adjacent to an Active Hazardous Waste Disposal Site," (85-72.7),
Presented at the 78th Annual Meeting of the Air Pollution Control
Association, Held on June 16-21, 1985 in Detroit, MI, Air Pollution
Control Association, Pittsburgh, PA, 1985.
Miller, Michele M. et al., "Relationships Between Octanol-Water
Partition Coefficients and Aqueous Solubility," Environmental
Science and Technology, Vol. 19, No. 6, 1985, pp. 522-529.
Mingelgrin, U. and Z. Gerstl, "Reevaluation of Partitioning as a
Mechanism of Nonionic Chemicals Absorption in Soils," Journal of
Environmental Quality, Vol. 12, No. 1, 1983, pp. 1-11.
Moore, Charles A., "Landfill Gas Generation, Migration and Controls,"
CRC Critical Reviews in Environmental Control, Vol. 9, No. 2,
November 1979, pp. 157-184.
Morrill, L. G., B. C. Mahilum, and S. H. Mohiuddin, Organic Compounds
in Soils; Sorption, Degradation and Persistence, Ann Arbor Science,
Ann Arbor, MI, 1982.
Morgan, R. Charles et al., "Endangerment Assessments for Superfund
Enforcement Actions," Proceedings of the Fifth National Conference
on Management of Uncontrolled Hazardous Waste Sites, Held on
November 7-9, 1984 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1984, pp. 213-216.
Murphy, Brian L., "Abandoned Site Risk Assessment Modeling and
Sensitivity Analysis," Proceedings of the National Conference on
Management of Uncontrolled Hazardous Waste Sites, Held on
November 29-December 1, 1982 in Washington, DC, Hazardous Materials
Control Research Institute, Silver Spring, MD, 1982, pp. 396-398.
127
-------
Napier, B. A. and K. A. Hawley, "A Ranking System for Mixed
Radioactive and Hazardous Waste Sites," Proceedings of the Fifth DOE
Environmental Protection Information MeeTTng, (CONF-841187), Held on
November 6-8, 1984 in Albuquerque, MM, U.S. Department of Energy,
Washington, DC, April 1985.
National Research Council, Acid Deposition Atmospheric Processes in
Eastern North America, National Academy Press, Washington, DC, 1983.
Neely, N. et al., Remedial Action at Hazardous Waste Sites; Survey
and Case Studies, (EPA 430/9-81-005), U.S. Environmental Protection
Agency, Cincinnati, OH, 1981.
NUS Corporation, Remedial Investigation Report (Phase III); Drake
Chemical Site, Lock Haven, Clinton County, Pennsylvania, NUS
Corporation, Pittsburgh, PA, January 1985.
NUS Corporation, Remedial Investigation Report, Beacon Heights
Landfill Site, Beacon Falls, Connecticut, NUS Corporation,
Pittsburgh, PA, April 1985.
NUS Corporation, Remedial Investigation Report. Volume 1. Taylor
Borough Site, Lackawanna County, Pennsylvania, NUS Corporation,
Pittsburgh, PA, May 1985.
NUS Corporation, Remedial Investigation Report/Feasibility Study of
Alteroatives. Volume 1. Berks Associates Douglassville Disposal
Site, Union Tovnship, Berks County, Pennsylvania, NUS Corporation,
Pittsburgh, PA, June 1985.
NUS Corporation, Remedial Investigation/Feasibility Study Report,
Volume 1, Millcreek Site, Erie County, Pennsylvania, NUS
Corporation, Pittsburgh, PA, August 1985.
NUS Corporation, Remedial Investigation/Feasibility Study Report,
Volume 1, Tybouts Corner Landfill, New Castle County, Delaware,
NUS Corporation, Pittsburgh, PA, June 1985.
NUS Corporation, Remedial Site Investigation Report; D'Imperio
Property Site, Township of Hamilton, Atlantic County, New Jersey,
NUS Corporation, Pittsburgh, PA, October 1984.
0'Sullivan, Denis, Construction Costs for Run-On/Run-Off Control at
Hazardous Waste Facilities. (WP-82W16), The MITRE Corporation,
McLean, VA, January 31, 1982.
128
-------
Office of Technology Assessment, Habitability of the Love Canal
Area: An Analysis of the Technical Basis for the Decision on the
Habitability of the Emergency Declaration Area, Office of Technology
Assessment, Washington, DC, June 1983.
Office of Technology Assessment, Nonnuclear Industrial Hazardous
Waste Classifying for Hazard Management A Technical Memorandum,
Office of Technology Assessment, Washington, DC, November- 1981.
Office of Technology Assessment, Testimony for the Record by the
Office of Technology Assessment, Hearing of House Energy and Commerce
Subcommittee on Oversight and Investigations, November 16, 1981.
Onishi, Y et al., "Computer-Based Environmental Exposure and Risk
Assessment Methodology for Hazardous Materials," (Draft), Submitted
to the Journal of Hazardous Materials, 1985.
Panaro, John, "Air Monitoring and Data Interpretation During Remedial
Action at a Hazardous Waste Site," Proceedings of the National
Conference on Hazardous Wastes and Environmental Emergencies, Held
on May 12-14, 1984 in Houston, TX, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1984, pp. 160-164.
Parry, G. D. R. and R. M. Bell, "Covering Systems," Contaminated
Land; Reclamation and Treatment, Michael A. Smith, ed., Plenum
Press, New York, NY, 1985.
Pellizzari, Edo D., "Analysis of Organic Vapor Emissions Near
Industrial and Chemical Waste Disposal Sites, Environmental Science
and Technology, Vol. 16, No. 11, 1982, pp. 781-785.
Pellizzari, Edo D., Measurement of Carcinogenic Vapors in Ambient
Atmospheres, (EPA-600/7-78-062), U.S. Environmental Protection
Agency, Research Triangle Park, NC, April 1978.
Pellizzari, E. D., et al., Interim Report on the Total Exposure
Assessment Methodology (TEAM) Study; First Season, Northern New
Jersey, (Draft), U.S. Environmental Protection Agency, Washington,
DC, June 1985.
Plumb, R. H., Jr., Characterization of Hazardous Sites, A Methods
Manual. Volume 3. Available Laboratory Analytical Methods,
(EPA-6UO/4-84-U38), U.S. Environmental Protection Agency, Las Vegas,
NV, May 1984.
Popendorf, William J., "Vapor Pressure and Solvent Vapor Hazards,"
American Industrial Hygiene Association Journal, Vol. 45, No. 10,
October 1984, pp. 719-726.
129
-------
Popendorf, William J., "Reply to G. A. Saunders," Americaa Industrial
Hygiene Association Journal, Vol. 46, No. 6, June 1985, p. B22,
Prasad, Surya S. and James S. Whang, "Partitioning Analysis of
Chemical Substances as a Tool for Managing Hazardous Waste Studies,"
Proceedings of the International Conference on New Frontiers for
Hazardous Waste Management, Held on September 15-18, 1985 in
Pittsburgh, PA, U.S. Environmental Protection Agency, Cincinnati,
OH, September 1985, pp. 377-385.
Priznar, Francis J. and Lucy P. Sibold, "Site Inspection Sampling
Strategy to Support the Hazard Ranking System Scoring," Proceedings
of the Sixth National Conference on Management of Uncontrolled
Hazardous Waste Sites, Held on November 4-6, 1985 in Washington, DC,
Hazardous Materials Control Research Institute, Silver Spring, MD,
1985, pp. 74-79.
Puskar, Mark A. and Steven P. Levine, "Characterization of Bulk
Materials on Remedial Action Sites: A Preliminary Comparison of
Compatibility Testing, FTIR-ATR and GS-MS," Proceedings of the
National Conference on Hazardous Wastes and Environmental
Emergencies, Held on May 14-16, 1985 in Cincinnati, OH, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1985,
pp. 111-114.
Rahn, Kenneth A., Douglas H. Lowenthal, and Noelle F. Lewis,
Elemental Tracers and Sources of Pollution Aerosols in Narragansett,
Rhode Island, Center for Atmospheric Studies - URI, Narragansett, RI,
October 1, 1982.
Raiffa, Howard, Decision Analysis; Introductory Lectures on Choices
under Uncertainty, Addison-Wesley, Menlo Park, CA, 1970.
Rich, Gerald, "Techniques for Air Pollution Analysis," Pollution
Engineering, Vol. XVII, No. 6, June 1985, pp. 43-44.
Riggin, R. M., Compendium of Methods for the Determination of
Tozic Organic Compounds in Ambient Air, (EPA-600/4-84-041), U.S.
Environmental Protection Agency, Research Triangle Park, NC, April
1984.
Rosbury, Keith D. and Stephen C. James, "The Control of Fugitive
Dust Emissions at Hazardous Waste Cleanup Sites," Proceedings of the
Fifth National Conference on Management of Uncontrolled Hazardous
Waste Sites, Held on November 7-9" 1984 in Washington. DC. Hazardous
Materials Control Research Institute, Silver Spring, MD, 1984,
pp. 265-267.
130
-------
R. E. Wright Associates, Inc., Draft Remedial Investigation Report
and Feasibility Study of Alternatives, Helen Kramer Landfill Site,
Mantua Township, Gloucester County, New Jersey, R. E. Wright
Associates, Inc., Middleton, PA, July 1985.
Rowe, William D., An Anatomy of Risk, John Wiley & Sons, New York,
NY, 1977.
Ryan, Robert M., Texas Experience in Ambient Air Sampling for Toxic
Wastes," Proceedings of the Sixth National Conference on Management
of Uncontrolled Hazardous Waste Sites, Held on November 4-6, 1985 in
Washington, DC, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1985, pp. 125-127.
Saari, Sharon and Alan Goldfarb, Hazard Ranking System Issue
Analysis; Classification of Hazardous Substances for Potential to
Accumulate in the Food Chain, (MTR-85W300), The MITRE Corporation,
McLean, VA, September 1986.
Saunders, G. A., "Comments on Popendorf, 'Vapor Pressure and Solvent
Vapor Hazards,'" American Industrial Hygiene Association Journal,
Vol. 46, No. 6, June 1985, pp. B20-B22.
Scheible, Mike et al., An Assessment of the Volatile and Toxic
Organic Emissions from Hazardous Waste Disposal in California,
Background Material for a Public Meeting, February 24, 1982, State
of California Air Resources Board, Sacramento, CA, February 1982.
Schultz, H. Lee et al., Superfund Exposure Assessment Manual (Final
Draft), Versar Inc., Springfield, VA, August 17, 1984.
Schweitzer, Glenn E., "Risk Assessment Near Uncontrolled Hazardous
Waste Sites: Role of Monitoring Data," Proceedings of the National
Conference on Management of Uncontrolled Hazardous Waste Sites, Held
on October 28-30, 1981 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1981, pp. 238-247.
Sedefian, Leon, Screening Procedures for Determining Ambient Impacts
of Toxic Contaminants, (Draft), New York Department of Environmental
Contamination, Albany, NY.
Sehmel, G.A., "Particle Resuspension: A Review," Environment
International, Vol. 4, 1980, pp. 107-127.
Shen, Thomas T., "Control Techniques for Gas Emissions from Hazardous
Waste Landfills," Journal of the Air Pollution Control Association,
Vol. 31, No. 2, February 1981, pp. 132-135.
131
-------
Sneu, Thomas T., "Estimating Hazardous Air Emissions from Disposal
Sites," Pollution Engineering, Vol. 13, No. 8, August 1981,
pp. 31-371
Shen, Thomas T., "Air Quality Assessment for Land Disposal of
Industrial Wastes," Environmental Management, Vol. 6, No. 4, 1982,
pp. 297-305.
Shen, Thomas T., "Estimation of Organic Compound Emissions from Waste
Lagoons," Journal of the Air Pollution Control Association, Vol. 32,
No. 1, January 1982, pp. 79-82.
Shen, Thomas T. and Granville H. Sewell, "Air Pollution Problems of
Uncontrolled Hazardous Waste Sites," Proceedings of the National
Conference on Management of Uncontrolled Hazardous Waste Sites, Held
on November 29-December 1, 1982 in Washington, DC, Hazardous
Materials Control Research Institute, Silver Spring, KD, 1982,
pp. 76-80.
Shen, Thomas T. and James Tofflemire, "Air Pollution Aspects of Land
Disposal of Toxic Waste," Journal of the Environmental Engineering
Division of ASCE, Vol. 106, No. EE1, February 1980, pp. 211-226.
Sims, Ronald and Jeffrey Baas, Review of In-Place Treatment
Techniques for Contaminated Surface Soils - Volume 1. Technical
Evaluation, (EPA-540/2-84-003a). U.S. Environmental Protection
Agency, Cincinnati, OH, September 1984.
Sims, Ronald et al., Review of In-Place Treatment Techniques for
Contaminated Surface Soils - Volume 2. Background Information for
In Situ Treatment, (EPA-540/2-84-003b), U.S. Environmental Protection
Agency, Cincinnati, OH, November 1984.
Skidmore, E. L. and N. P. Woodruff, Wind Erosion Forces in the United
States and Their Use in Predicting Soil Loss, (Agriculture Handbook
No. 346), U.S. Department of Agriculture, Washington, DC, April 1968.
Skipa, Kenneth J., Donald F. Elias, and Jeffrey D. Gram, "Monitoring
and Evaluating Multiple Source Emissions at Hazardous Waste Sites,"
(85-69.1), Presented at the 78th Annual Meeting of the Air Pollution
Control Association, Held on June 16-21, 1985 in Detroit, MI, Air
Pollution Control Association, Pittsburgh, PA, 1985.
Smith, Al J., Jr., et al., Atmospheric Emergencies: Existing
Capabilities and Future Needs, (TRB/TRR-902), Transportation Research
Board, National Academy of Sciences, Washington, DC, 1983.
132
-------
Smith, Michael A., ed., Contaminated Land; Reclamation and
Treatment, Plenum Press, New York, NY, 1985, pp. 407-417-
Southworth, George R., "The Role of Volatilization in Removing
Polycyclic Aromatic Hydrocarbons from Aquatic Environments," Bull.
Environm. Contam. Toxicol., Vol. 21, 1979, pp. 507-514.
Springer, Charles et al., "Secondary Emissions from Hazardous Waste
Disposal Lagoons: Field Measurements," Land Disposal of Hazardous
Waste; Proceedings of the Ninth Annual Research Symposium,
(EPA-600/9-83-018), U.S. Environmental Protection Agency,
Cincinnati, OH, September 1983, pp. 58-69.
Springer, Charles, Louis J. Thibodeaux, and Shrikrisna Chatrathi,
"Simulation Study of the Volatilization of Polychlorinated Biphenyls
from Landfill Sites," Environment and Solid Wastes Characterization,
Treatment and Disposal, Francis, C. W. and S. E. Auerbach, eds.,
Proceedings of the Fourth Life Sciences Symposium, Environment and
Solid Wastes, Held on October 4-8, 1981 in Gatlinburg, TN,
Butterworth Publishers, Woburn, MA, 1983, pp. 209-222.
Stael von Holstein, Carl-Axel S., and James E. Matheson, A Manual
for Encoding Probability Distributions, (Final Report), SRI
International, Menlo Park, CA, September 1978.
State of California Air Resources Board, An Assessment of the
Volatile and Toxic Organic Emissions from Hazardous Waste Disposal
in California, Background Material for a Public Meeting, February 24,
1982, State of California Air Resources Board, Sacramento, CA,
February 1982, p. 31.
State of New Jersey, Comments on Proposed Revisions of the National
Contingency Plan, (NCP) 47 FR 10972, State of New Jersey, Department
of Law and Public Safety, Trenton, NJ, April 26, 1982.
Stoner, Ken M., A Decision Model for Evaluating Land Disposal of
Hazardous Wastes, School of Systems and Logistics, Air Force
Institute of Technology, Wright-Patterson Air Force Base, OH, 1982.
Sullivan, David A. and Jerome 3. Strauss, "Air Monitoring of a
Hazardous Waste Site," Proceedings of the National Conference on
Management of Uncontrolled Hazardous Waste Sites, Held on
October 28-30, 1981 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1981, pp. 136-142.
Thibodeaux, Louis J., Chemodynamics Environmental Movement of
Chemicals in Air, Water, and Soil, John Wiley and Sons, Inc.,
New York, NY, 1979.
133
-------
Thibodeaux, Louis J., "Estimating The Air Emissions of Chemicals
from Hazardous Waste Landfills," Journal of Hazardous Materials,
Vol. 4, 1981, pp. 235-244.
Thibodeaux, Louis J. et al. , "Air Emission Monitoring of Hazardous
Waste Sites," Proceedings of the National Conference on Management
of Uncontrolled Hazardous Waste Sites, Held on November 29-
December 1, 1982 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1982, pp. 70-75.
Thibodeaux, Louis J. et al., "Chemical Volatilization Mechanisms
from Surface Impoundments in the Absence of Wind," Land Disposal of
Hazardous Waste: Proceedings of the Eighth Annual Research
Symposium, (EPA-600/9-82-002), U.S. Environmental Protection Agency,
Cincinnati, OH, March 1982, pp. 161-173.
Thibodeaux, Louis and B. Becker, "Chemical Transport Rates Near the
Sediment in Wastewater Impoundments," Environmental Progress,
Vol. 1, No. 4, November 1982, pp. 296-3D1E
Thibodeaux, Louis J. and Seong T. Hwang, "Landfarming of Petroleum
Wastes - Modeling the Air Emission Problem," Environmental Progress,
Vol. 1, No. 1, February 1982, pp. 42-46.
Thibodeaux, Louis J., David C. Parker, and Howell H. Heck, "Chemical
Emissions from Surface Impoundments," Environmental Progress,
Vol. 3, No. 2, May 1984, pp. 73-78.
Thibodeaux, Louis J., Charles Springer, and Guadalupe Hildebrand,
"Air Emissions of Volatile Organic Chemicals from Landfills: A
Pilot Study," Land Disposal of Hazardous Waste; Proceedings of the
Tenth Annual Research Symposium, (EPA-600/9-84-QQ7), U.S.
Environmental Protection Agency, Cincinnati, OH, August 1984,
pp. 172-180.
Thibodeaux, Louis J., Charles Springer, and Rebecca S. Parker,
"Design for Control of Volatile Chemical Emissions from Surface
Impoundments," Hazardous Waste and Hazardous Materials, Vol. 2,
No. 1, 1985, pp. 99-106.
Thibodeaux, Louis J., Charles Springer, and L. M. Riley, "Models of
Mechanisms for the Vapor Phase Emission of Hazardous Chemicals from
Landfills," J. Hazardous Materials, Vol. 7, No. 1, 1982, pp. 63-74.
Thornthwaite, C. Warren, "An Approach Toward Rational Classification
of Climate," Geophysical Review, Vol. 38, 1948, pp. 55-94
134
-------
Thornthwaite, C. Warren, "The Climates of North America According to
a New Classification," Geographical Review, Vol. 21, 1931,
pp. 633-655.
Todd, David and Ralph Propper, "Methods to Determine Emissions and
Possible Health Effects of Organic Compounds from California
Landfills," (85-73.2), Presented at the 78th Annual Meeting of the
Air Pollution Control Association, Held on June 16-21, 1985 in
Detroit, MI, Air Pollution Control Association, Pittsburgh, PA, 1985.
Turpin, Rodney D., "ERT's Air Monitoring Guides for Uncontrolled
Hazardous Waste Sites," Proceedings of the National Conference on
Management of Uncontrolled Hazardous Waste Sites, Held on October 31-
November 2, 1983 in Washington, DC, Hazardous Materials Control
Research Institute, Silver Spring, MD, 1983, pp. 82-84.
Turpin, Rodney D., "On-site Air Monitoring Classification by Use of
the ERT Two-Stage Collection Tube," Proceedings of the National
Conference on Management of Uncontrolled Hazardous Waste Sites, Held
on October 31-November 2, 1983 in Washington, DC, Hazardous Materials
Control Research Institute, Silver Spring, MD, 1983, p. 85.
U.S. Department of. Commerce, National Oceanic and Atmospheric
Administration, Local Climatological Data; Annual Summaries for
1983, U.S. Department of Commerce, National Oceanic and Atmospheric
Administration, Washington, DC, 1984.
U.S. Environmental Protection Agency, Damages and Threats Caused by
Hazardous Material Sites, (EPA-430/9-80-004), U.S. Environmental
Protection Agency, Washington, DC, May 1980.
U.S. Environmental Protection Agency, Field Standard Operating
Procedures for Air Surveillance F.S.O.P. 8, (Draft), U.S.
Environmental Protection Agency, Environmental Response Team,
Washington, DC, 1985.
U.S. Environmental Protection Agency, Guidance Document for Subpart F
Air Emission Monitoring Land Disposal Toxic Air Emissions Evaluation
Guideline, U.S. Environmental Protection Agency, Washington, DC,
December 1980.
U.S. Environmental Protection Agency, Guidance on Remedial
Investigations Under CERCLA, (EPA-540/G-85-002), U.S. Environmental
Protection Agency, Washington, DC, June 1985.
U.S. Environmental Protection Agency, Land Disposal of Hazardous
Waste; Proceedings of the Seventh Annual Research Symposium,
(EPA-600/9-81-002b), U.S. Environmental Protection Agency,
Cincinnati, OH, March 1981.
135
-------
U.S. Environmental Protection Agency, Land Disposal of Hazardous
'.iaste; Proceedings of the Eighth Annual Research Symposium,
TEPA-600/9-82-002), U.S. Environmental Protection Agency,
Cincinnati, OH, March 1982.
U.S. Environmental Protection Agency, Uncontrolled Hazardous Waste
Site Ranking System: A Users Manual, (HW-10), U.S. Environmental
Protection Agency, (FR 47 31219-31243, July 16, 1982).
U.S. Environmental Protection Agency, Land Disposal of Hazardous
Waste; Proceedings of the Ninth Annual Research Symposium,
(EPA-600/9-83-018), U.S. Environmental Protection Agency,
Cincinnati, OH, September 1983.
U.S. Environmental Protection Agency, Land Disposal of Hazardous
Waste; Proceedings of the Tenth Annual Research Symposium,
(EPA-600/9-84-007), U.S. Environmental Protection Agency,
Cincinnati, OH, August 1984.
U.S. Environmental Protection Agency, Standard Operating Safety
Guides, U.S. Environmental Protection Agency, Washington, DC,
November 1984.
U.S. Environmental Protection Agency, Subtitle C, Resource
Conversation and Recovery Act of 1976 Final Environmental Impact
Statement - Part I Final Draft, (SW - 188c), U.S. Environmental
Protection Agency, Washington, DC, 1980.
U.S. Environmental Protection Agency, Superfund Public Health
Evaluation Manual, (EPA-540/1-86/060, OSWER Directive 9285 4-1),
U.S. Environmental Protection Agency, Washington, DC, October 1986.
U.S. Environmental Protection Agency et al., Proceedings of the
National Conference on Management of Uncontrolled Hazardous Waste
Sites, Held on October 15-17. 1980 in Washington. DC. Hazardous
Materials Control Research Institute, Silver Spring, MD, 1980.
U.S. Environmental Protection Agency et al., Proceedings of the
National Conference on Management of Uncontrolled Hazardous Waste
Sites, Held on October 28-30. 1981 in Washington. DC. Hazardous
Materials Control Research Institute, Silver Spring, MD, 1981.
U.S. Environmental Protection Agency et al., Proceedings of the
National Conference on Management of Uncontrolled Hazardous Waste
Sites, Held on November 29-December 1, 1982 in Washington, DC,
Hazardous Materials Control Research Institute, Silver Spring, MD,
1982.
136
-------
U.S. Environmental Protection Agency et al., Proceedings of the
National Conference on Management of Uncontrolled Hazardous Waste
Sites, Held on October 31-November 2, 1983 in Washington, DC,
Hazardous Materials Control Research Institute, Silver Spring, MD,
1983.
U.S. Environmental Protection Agency et al., Proceedings of the
Fifth National Conference on Management of Uncontrolled Hazardous
Waste Sites, Held on November 7-9, 1984 in Washington, DC, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1984.
U.S. Environmental Protection Agency et al., Proceedings of the
Sixth National Conference on Management of Uncontrolled Hazardous
Waste Sites, Held on November 4-6, 1985 in Washington, DC, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1985.
U.S. Environmental Protection Agency et al., Proceedings of the
International Conference on New Frontiers for Hazardous Waste
Management, (EPA/6UU-9-85-U25), Held on September 15-18, 1985 in
Pittsburgh, PA, U.S. Environmental Protection Agency, Cincinnati,
OH, September 1985.
Vaught, Charles C., "A Basic Programming Technique for the
Estimation of VOC Emissions from Hazardous Waste Treatment, Storage,
and Disposal Facilities," (85-73.8), Presented at the 78th Annual
Meeting of the Air Pollution Control Association, Held on June 16-21,
1985 in Detroit, MI, Air Pollution Control Association, Pittsburgh,
PA, 1985.
Versar, Inc., Physical-Chemical Properties and Categorization of
RCRA Waste According to Volatility, Versar Inc., Springfield, VA,
September 28, 1984.
Vogel, Gregory A. and Denis F. 0'Sullivan, Air Emission Control
Practices at Hazardous Waste Management Facilities, (MTR-83W89), The
MITRE Corporation, McLean, VA, June 1983.
Vogt, W. Gregory and James J. Walsh, "Volatile Organic Compounds in
Gases from Landfill Simulators," (85-73.5), Presented at the 78th
Annual Meeting of the Air Pollution Control Association, Held on
June 16-21, 1985 in Detroit, MI, Air Pollution Control Association,
Pittsburgh, PA, 1985.
Wallace, Lance A., et al., "Personal Exposures, Indoor-Outdoor
Relationships, and Breath Levels of Toxic Air Pollutants Measured
for 355 Persons in New Jersey," Atmospheric Environment, Vol. 19,
No. 10, 1985, pp. 1651-1661.
137
-------
Wallace, Lance A., et al., "Personal Exposures, Outdoor
Concentrations, and Breath Levels of Toxic Air Pollutants Measured
for 425 Persons in Urban, Suburban and Rural Areas," Presented at
the 77th Annual Meeting of the Air Pollution Control Association,
Held on June 25, 1984 in San Francisco, CA, Air Pollution Control
Association, Pittsburgh, PA, 1984.
Walsh, Gary, "Control of Volatile Air Emissions from Hazardous Waste
Land Disposal Facilities," Proceedings of the National Conference on
Hazardous Wastes and Environmental Emergencies, Held on May 12-14,
1984 in Houston, TX, Hazardous Materials Control Research Institute,
Silver Spring, MD, 1984, pp. 146-153.
Walsh, James F. and Kay H. Jones, "The Air Quality Impact Risk
Assessment Aspects of Remedial Action Planning," Proceedings of the
National Conference on Management of Uncontrolled Hazardous Waste
Sites, Held on November 29-December 1, 1982 in Washington, DC,
Hazardous Materials Control Research Institute, Silver Spring, MD,
1982, pp. 63-66.
Watson, J. and K. Barrett, Uncontrolled Hazardous Waste Site Ranking
System - A Sensitivity Analysis, (WP-82W211), The MITRE Corporation,
McLean, VA, February, 1982.
Weast, Robert C., ed., CRC Handbook of Chemistry and Physics, 58th
Edition, CRC Press, Inc., 1977.
Wetherold, Robert G., Donald D. Rosebrook, and E. W. Cunningham,
"Assessment of Hydrocarbon Emissions from Land Treatment of Oily
Sludges," Land Disposal of Hazardous Waste: Proceedings of the
Seventh Annual Research Symposium, (EPA-600/9-81-002b)7 U.S.
Environmental Protection Agency, Cincinnati, OH, March 1981,
pp. 213-223.
Whelan, G. and B. L. Steelman, "Development of Improved Risk
Assessment Tools for Prioritizing Hazardous and Radioactive-Mixed
Waste Disposal Sites," (PNL-SA-12708), Presented at the 5th DOE
Environmental Protection Information Meeting, Albuquerque, NM,
November 6-8, 1984, Pacific Northwest Laboratory, Richland, WA,
October 1984.
Wiegand, Claudia et al., A Characterization of Hazardous Waste
Materials Disposed Of in California, (ARB/R-84/233). State of
California Air Resources Board, Sacramento, CA, September 30, 1984.
Wolfinger, Thomas F., Hazard Ranking System Issue Analysis;
Carcinogenic Risk Analysis of the Air Pathway Target Distance Limit.
(MTR-86W140), The MITRE Corporation, McLean, VA, September 1986a.
13d
-------
Wolfinger, Thomas F., Hazard Ranking System Issue Analysis;
Indoor Air Contamination Arising from Uncontrolled Wastes Site,
(MTR-86W132;, The MITRE Corporation, McLean, VA, August 1987b.
Zegel, William C., "An Overview of Hazardous Waste Issues," Journal
of the Air Pollution Control Association, Vol. 35, No. 1, January
pp. 50-54.
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APPENDIX A
SUMMARY OF AIR MONITORING DATA AT SELECTED WASTES SITES
This appendix presents a compilation of available data on the
ambient air contaminant concentrations arising from selected wastes
sites. The data are limited in scope and are presented to indicate
the magnitude of the air contamination problems that might arise
from wastes sites.
141
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TABLE A-i
PCB CONCENTRATIONS AT SELECTED SITES
Site Concentration (ug/mr)
Caputo 0.05 - 3 (winter)
246 - 300 (summer)
Lehigh Elect 0.0075
New Bedford 0.021 (winter)
0.41 - 1.5 (summer)
Source: Adapted from Smith, Michael A., ed., Contaminated Land:
Reclamation and Treatment, Plenum Press, New York, NY,
1985, pp. 407-417.
142
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TABLE A-2
AMBIENT AIR CONCENTRATIONS OF SELECTED COMPOUNDS AT
THREE CALIFORNIA HAZARDOUS WASTES DISPOSAL FACILITIES
(ppb Carbon)
BKK
Kettleman Hills
IT-Martinez
Compound
Upwind Downwind Upwind Downwind Upwind Downwind
n-Hexane
Benzene
n-Heptane
Toluene
n-Octane
Ethyl Benzene
Xylenes
Dichloro-
benzene
Total
12
10
8
52
5
10
46
0
143
139
115
86
952
158
37
157
0
1644
11
13
6
25
3
3
15
0
76
75
106
185
123
84
64
239
0
876
10
8
7
22
2
3
11
3
66
12
16
15
30
3
9
19
2
106
Note: Monitoring conducted by Illinois Institute of Technology for
EPA during November and December 1979.
Source: Scheible et al., 1982.
143
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TABLE A-3
AMBIENT AIR CONCENTRATIONS OF SELECTED COMPOUNDS AT
THREE CALIFORNIA HAZARDOUS WASTES DISPOSAL FACILITIES
(ppb Carbon)
BKK
Kettleman Hills
IT-Martinez
Compound
Ethane
Ethene
Propane
Acetylene
1-Butane
n-Butane
Propene
Propadiene
i-Pentane
n-Pentane
1-Butene
i-Butene
Total
Upwind Downwind Upwind Downwind Upwind Downwind
15
29
19
35
23
50
10
53
31
4
11
280
76
100
370
48
730
440
49
4
800
650
35
48
3350
28
18
29
18
11
26
5
30
19
8
192
27
15
27
14
11
67
4
170
140
2
11
488
28
23
88
20
80
93
11
110
56
7
16
532
15
18
13
14
86
21
5
23
14
209
Note: Monitoring conducted by State of California Air Resources
Board during November and December 1979.
Source: Scheible et al., 1982.
144
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TABLE A-4
POTENTIALLY CARCINOGENIC, TOXIC, MUTAGENIC, OR
TERATOGENIC COMPOUNDS MEASURED AT THE BKK SITE
(Maximum Detected Concentrations)
Compound
Benzene
Vinyl Chloride
Chloroform
Carbon Tetrachloride
Dioxane
Tetrachlorethane
Tetrachloroethylene
Methyl Chloroform
Trichloroethylene 36.0
Note: Monitoring conducted by University of Southern California
during November 1979-June 1980; January 1981; and February
1981. Facility was in operation at this time.
Source: State of California Air Resources Board, An Assessment of
the Volatile and Toxic Organic Emissions from Hazardous
Waste Disposal in California, Background Material for a
Public Meeting, February 24, 1982, State of California Air
Resources Board, Sacramento, CA, February 1982, p. 31.
145
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TABLE A-5
AVERAGE CONCENTRATIONS OF CONTAMINANTS DETECTED AT
SELECTED NEW JERSEY DISPOSAL SITES
(ppb volume)
Compound
Vinylidene Chloride
Methylene Chloride
Chloropyrene
Chloroform
1-2 Dichloroethane
1-1-1 Trichl or oe thane
Benzene
Carbon Tetrachloride
I richlor oe thylene
Dioxane
1-1-2 Trichloroe thane
Toluene
1-2 Dibromoethane
Tetrachloroe thylene
Chlorobenzene
Ethylbenzene
m&p Xylene
Styrene
o-Xyiene
1-1-2-2 Tetra-
chloroe thane
o-Chlorotoluene
p-Chlorotoluene
p-Dichlorobenzene
o-Di chlorobenzene
Nitrobenzene
Naphthalene
Site A
0
0.09
0
0.33
0.01
0.38
4.98
0.06
0.39
0
0.02
42.09
0.25
0.92
0.53
3.56
9.95
0.62
3.09
0.24
0.4
0.71
0.24
0.35
1.38
0.88
Site B
0.39
0.49
0
0.64
0
0.51
2.55
0.12
0.36
0
0.02
11.52
0.25
1.03
0.09
0.78
2.18
0.27
0.93
0.05
0.06
0.06
0.1
0.11
0.23
0.2
Site C
36.44
11.34
0.01
0.91
0.28
3.04
7.66
0.1
2.86
0.01
1.26
51.91
0.36
2.03
0.78
3.91
7.72
1.3
2.27
0.59
0.43
0.39
0.51
0.77
0.48
0.27
Site D
3.46
0.9
0
0.21
0.03
0.84
1.33
0.04
0.21
0
0.32
15.16
0.06
0.38
0.32
0.61
1.52
0.11
0.42
0.02
0.05
0.07
0.08
0.11
0.12
0.11
Site E
1.6
1.14
0
0.08
0
0.57
0.6
0.03
0.08
0
0.29
3.28
0.05
0.12
0.09
0.13
0.37
0.13
0.15
0.01
0.02
0.04
0.04
0.06
0.01
0.1
Landfill
2.61
1.58
0
0.12
0
1.29
3.33
0.02
0.34
0
0.11
27.79
0.02
1.53
0.15
1.53
3.35
0.41
0.9
0.01
0.01
0.03
0.06
0.06
0
0.08
Note: Detection limit of 0.01 substituted for values below detection limit.
Source: Adapted from LaRegina, J. E. et al., 1984.
146
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APPENDIX B
DISCUSSION OF REJECTED OPTIONS
This appendix presents discussions of the scoring options that
were developed and rejected. A short description of each option is
presented, followed by the reasons for its rejection.
B.I Evaluating Ambient Monitoring Data for Observed Releases
Two basic options for evaluating ambient monitoring data for
observed release were developed. These options would employ ambient
measurements that might not "significantly" exceed background or may
be surrogates for ambient air measurements in assigning an observed
release value. This option would maintain the current approach:
existence of data showing concentrations significantly above
background results in a maximum value, 45. Other monitoring results
would be evaluated as in Table B-l. The following relationship
would hold between the values
0 < A < B < C < 45
Thus, a zero value would be assigned if and only if a comprehensive
monitoring program showed no detectable levels of contamination.
An alternate, similar option developed would allow data other
than ambient air data to be used. For example, evidence of surface
soil contamination, relative to background levels, could be utilized
in a process similar to that for ambient air data suggested above.
A minimum acceptable area of contamination would have to be set as
well.
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TABLE fl-1
EVALUATING MONITORING RESULTS
Monitoring Result Value
No Contaminants Detected
• Comprehensive monitoring program* 0
• Limited monitoring program* A
Contaminants Detected
• Background above analytical** detection limit B
- Contamination level below analytical detection limit
- Contamination level above analytical detection limit C
but not significantly above background
- Contamination level significantly above background 45
• Background below analytical detection limit C
- Contamination level below analytical detection limit
- Contamination level above analytical detection limit 45
*Guidance would be provided as to the definition of comprehensive
and limited monitoring programs.
**The analytical detection limit reflects the combination of
instrument and laboratory detection limits. These differ for
different instruments and laboratory methods.
148
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Further minor variations might be developed using alternate
values and data categories such as vegetation injury.
The above options were rejected since in the interest of
maintaining simplicity in the observed release category and as
placing too much emphasis on data of questionable quality and
meaning. The basic concept led to the development of the also
rejected "inconclusive monitoring" emission source descriptors (see
Section B.2.2) and the adopted exceptions in the mobility factor
(see Section 3.3.2).
B.2 Potential to Release Options
B.2.1 Emissions Estimation Approach
The principal alternative to the engineering factors approach
adopted in the two options discussed previously is the emissions
estimation approach. In this approach, emissions equations would be
used to estimate the emissions from a site and a value assigned
based on the magnitude of the emissions estimate. Several emissions
equations are available for generic waste disposal and treatment
processes. Breton, et al. (1984) and Balfour, Wetherold and Lewis
(1985) present fairly comprehensive discussions and evaluations of
the emissions models currently available. Durham (1985) presents a
discussion of ongoing EPA efforts to improve these models. Some of
the models have been verified in field studies with good success
(Balfour, W. D., et al., 1984, Caravanos, Sewell, and Shen, 1985).
Many of these models have also been employed by EPA in policy
149
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studies (Breton, et al., 1983; Battye, et al., 1985). A review of
this and related literature indicates that an emissions estimation
approach would probably be feasible. The approach, however, was
rejected for several reasons.
First, many of tne equations are complex and require a fairly
high level of sophistication to employ them properly. It was
believed that the requisite high level of expertise would not be
readily available in the field. Further; the equations require data
that are not generally available. Some of the data are available in
standard references, for standard conditions. The principal data of
this type are the mass transfer coefficients, which are available
for only a limited number of chemicals in idealized environments.
It is possible to incorporate methods to calculate tnese factors
from readily available data (e.g., vapor pressure) in many cases.
However, these methods further complicate the calculations, do not
always account for important, difficult to evaluate site
characteristics, and generally lower the confidence in the final
result. Of particular importance in this context is the effect of
waste mingling on equation parameter values. Additional data that
are necessary in many of the equations include site-specific data on
detailed soil characteristics and meteorological factors.
Second, the equations are not available addressing many of the
situations encountered in CERCLA sites. Of particular importance
are sites containing broken drums or tanks, either exposed or
150
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buried. Equations applicable to this common circumstance are not
currently available. Further, the equations are idealized and do
not reflect the deviations from design that are encountered in
uncontrolled sites.
Finally, many of the emissions estimation approaches require
air monitoring data to back-calculate emissions rates. If such data
were available, then the potential to release option would not have
to be employed at all.
In summary, the emissions estimation approach is probably
technically feasible, but would be very difficult to implement.
B.2.2 Inconclusive Monitoring Descriptors
During the course of refining Options 1 and 2, five emission
source descriptors were developed for monitoring results that did
not indicate an observed release. The idea behind these
"inconclusive monitoring" descriptors was to make use of monitoring
results that, even though they did not indicate an observed release,
would affect a subjective judgment of the probability that the site
was or would soon release a significant amount of contaminants.
These descriptors are listed in Table B-2.
After much discussion, these five descriptors were deleted for
two reasons. First, it was believed that if the air data collected
at the site do not indicate an observed release, then they are also
not of sufficient quality to use as emission source descriptors.
Second, the information contained in these data would be better used
151
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TABLE B-2
"INCONCLUSIVE MONITORING" EMISSION SOURCE DESCRIPTORS
Code Descriptor
Ambient air monitoring results:
Background at or above analytical detection limit:
30 - Contamination level below analytical detection limit
31 - Contamination level at or above analytical detection limit but
not significantly above background
32 - Contamination level significantly above background but of
insufficient quality to constitute an observed release
Background below analytical detection limit:
33 - Contamination level below analytical detection limit
34 - Contamination level significantly above background but of
Insufficient quality to constitute an observed release
152
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in assessing contaminant mobility and, hence, the exceptions to the
contaminant mobility factor discussed in Section 3.3.
B.2.3 Site Age
A review of the processes that lead to air releases indicates
that the dominant factors in determining release potential are the
nature (e.g., mobility) and quantity of the waste in the site and
the site containment. Since the processes that determine emission
levels are continuous, the duration of time these processes have
been in operation determines the quantity of waste remaining on the
site and to a lesser extent, the nature of the waste. Thus, the
time between disposal and site investigation, or the site age, is a
crucial factor in determining emission potential that is not
addressed in Options 1 and 2. There are two reasons for this
apparent omission. First, no viable measure of the time between
investigation and disposal could be defined. It is generally not
possible to determine the date at which wastes were deposited at a
site. Further, wastes were often deposited at different times and
in different amounts and mixtures over a long period of time.
Surrogate measures, such as years since site opening and years since
site closing, suffer from similar information collection problems
and may differ significantly from the actual years since disposal.
Second, the interaction between site age and contaminant mobility is
very complex and could not be simplified enough to allow both to be
incorporated in the options.
153
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B.2.4 Mobility Factors
Two alternate approaches to the Versar approach for evaluating
contaminant mobility were investigated: partition coefficients and
fugacity. Partition coefficients (Leo, Hansch and Elkins, 1971;
Chiou, Schmedding, and Manes, 1982; Mingelgrin and Gerstl, 1983;
Miller, et al., 1985) reflect the propensity of a compound to
distribute between two other compounds or solution phases. For
example, the octanol-water partition coefficient of a compound
reflects the propensity of that compound to distribute between
octanol and water within a combined solution. The octanol-water
partition coefficient has been suggested as a measure of
bioaccumulation (Saari and Goldfarb, 1986). They are also
potentially useful in managing waste disposal, as an indication of
the mobility of contaminants in various solutions (Prasad and Whang,
1985).
The fugacity of a compound is somewhat similar to a partition
coefficient (Mackay, 1979; Mackay and Paterson, 1981, 1982, and
1984). However, fugacity reflects the long-term propensity of a
compound to distribute among environmental media rather than between
two solutes such as octanol and water, for example. The media of
concern, for example, can include air, water, sediment, aquatic
biota, and soil. Fugacity can be used to calculate the long-term
equilibrium distribution of a chemical in the environment.
154
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The use of partition coefficients were rejected for several
reasons. In both Options 1 and 2, contaminant mobility reflects the
ability of a contaminant to move offsite due to the contaminant
physiochemical characteristics. Partition coefficients measure the
propensity of the contaminant to distribute among solutions. They
do not reflect the propensity of a contaminant to volatilize, only
the possibility to migrate to the air-surface interface. These
coefficients are applicable to mobility only to the extent that the
distribution between solutions indicate ability to migrate. This,
in turn, depends on the migration potential of the solute, which is
generally unknown. Further, the partition coefficient depends on
the contaminant in question and the two solutes. The same compound
may have very different octanol-water and organic carbon partition
coefficients. The choice of the best applicable coefficient at a
site depends on the actual site waste composition, information that
is generally unavailable. Finally, only octanol-water partition
coefficients are available for the contaminants generally
encountered at wastes sites.
The use of fugacity was rejected primarily because of a lack of
available fugacity data for the contaminants of interest and the
complexity of the fugacity calculation approaches. It was felt that
these calculations were too complex to be employed in the field.
Less important reasons include the concern that fugacity reflects
long-term equilibrium behavior rather that short-term transport
155
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phenomena. Fugacity would be a misleading measure of mobility
whenever the long-term distribution of a chemical differed
significantly from its short-term local distribution.
B.2.5 Alternate Methods for Combining Containment Values
Several alternate methods for combining containment values were
considered. The first option developed employs a single containment
factor approach, combining the particulate matter and gas containment
aspects of a site. The containment descriptors and values are
listed in Table B-3. This approach was rejected as being inferior
to the two-factor approach presented in Options 1 and 2, while not
really representing a significant simplification (see the matrix
approaches in Table B-3).
Additional options for combining the two containment values are
as follows:
• Three-level containment scale (0-2) for gases and particulate
matter, combined value is the sum of the two values with a
maximum value of 3.
• Four-level containment scale (0-3) for gases and particulate
matter, combined value is the maximum of the two values.
• Four-level containment scale (0-3) for gases and particulate
matter, combined value is the sum of the two values with a
maximum value of 3.
• Three-level containment scale (0-2), the combined value is
the maximum of the two values unless both are equal to two,
in which case the combined value is J.
The adopted approach, which reflects the viewpoint that emissions
are determined by the least restrictive containment, was deemed
superior to these alternatives.
156
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TABLE B-3
SINGLE CONTAINMENT FACTOR APPROACH
ACTIVE FIRE SITE 3_
BURIED TANKS
• Depth to tanks at least six inches; soil resistant 1_
to gas migration
• Depth to tanks at least six inches; soil not 2_
resistant to gas migration
• Other 0_
CONTAMINATED SURFACE SOIL
See Matrix Procedure 1
EXPOSED DRUMS
Drums intact 1
Drums broken 3
EXPOSED TANKS
• Open Roof Tanks
- Dome intact; seals intact 0_
- Dome intact; seals broken; waste covered with 1_
a stable immiscible fluid
- Dome intact; seals broken; waste covered with 1_
floating spheres
- Undomed or dome not intact; waste covered with 2_
a stable immiscible fluid
- Undomed or dome not intact; waste covered with 2_
floating spheres
- Other 0_
• Fixed and Floating Roofs
- Structurally intact; seals intact
— Conservation vents intact and functioning 0_
— Conservation vents intact but not functioning 1
157
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TABLE B-3 (Continued)
EXPOSED TANKS (Concluded)
- Structurally intact; seals intact (Concluded)
— Waste covered with a stable inert gas
— Waste covered with floating spheres
— Insulated
— Waste covered with a stable immiscible fluid
— Other
- Structurally intact; seals broken
— Conservation vents intact and functioning
— Conservation vents intact but not functioning
— Waste covered with a stable inert gas
— Waste covered with floating spheres
— Insulated
— Waste covered with a stable immiscible fluid 2
— Other ?
- Structurally not intact
— Conservation vents intact and functioning 0
— Conservation vents intact but not functioning 1
— Waste covered with a stable inert gas 1
— Waste covered with floating spheres 1
— Insulated 2
— Waste covered with a stable immiscible fluid
— Other
- Other
INACTIVE ABOVEGROUND FI&E SITE
See Matrix Procedure 2
LANDFARM/LANPTREATMENT
See Matrix Procedure 3
LANDFILL
See Matrix Procedure 4
OPEN PIT
SPILL SITE
See Matrix Procedure 5
158
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TABLE B-3 (Continued)
SURFACE IMPOUNDMENTS
• Enclosed Impoundment*
- Synthetic cover intact
- Impoundment covered with floating spheres
- Stable surfactant layer covering impoundment
Synthetic cover torn 2_
Unstable or incomplete surfactant layer 2
Other D~
• Open impoundment (not enclosed)
- Impoundment covered with floating spheres
- Stable surfactant layer covering impoundment
- Synthetic cover intact
- Synthetic cover torn
- Other
SURFACE WATER BODY OR OUTFALL
UNDERGROUND INJECTION
• Depth of injection at least x inches
• Depth of injection less than x inches
WASTE PILE
See Matrix Procedure b
*An enclosed impoundment is one with a freeboard exceeding two feet
in height or one that is substantially surrounded by a wall, fence,
trees or other adequate windbreak.
159
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TABLE B-3 (Continued)
MATRIX PROCEDURE 1
CONTAMINATED SURFACE SOIL
Evaluate the site separately for the following containment factors:
Particulate Containment (choose applicable characteristic with
lowest value):
• Site covered with an essentially impermeable cover 0_
or heavily vegetated. No exposed soil or liquids
(e.g., paved-over)
• Enclosed in an intact building 1_
• Site substantially vegetated or covered with a 1_
nonwater based dust suppressing fluid. Little
exposed soil or liquids
• Enclosed in an nonintact building 2_
• Site lightly vegetated or lightly covered with a 2_
nonwater dust suppressing fluid. Much exposed soil
or liquids
• Slope average less than 10 degrees 2_
• Substantially surrounded with mesh fence 2
• Site substantially devoid of vegetation. Large 3
percentage of exposed soil or liquids
• Other 0
Gas Containment:
• Enclosed in an intact building 1
• Covered with an intact synthetic cover 1
• Covered with a nonintact synthetic cover 2
• Enclosed in a nonintact building 2
• Other 0
160
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TABLE B-3 (Continued)
Combine the two containment values as follows:
Level of Gas Containment
Level of
Particulate
Containment
0:
1:
2:
3:
0
0
1
2
3
1
1
1
2
3
2
2
2
2
3
,3
3
3
3
3
161
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TABLE B-3 (Continued)
MATRIX PROCEDURE 2
INACTIVE ABOVEGROUND FIRE SITE
Evaluate the site separately for the following containment factors:
Particulate Containment (choose applicable characteristic with
lowest value):
• Site covered with an essentially impermeable cover 0_
or heavily vegetated. No exposed soil or liquids
(e.g., paved-over)
• Enclosed in an intact building 1
• Site substantially vegetated or covered with a 1_
nonwater-based dust suppressing fluid. Little
exposed soil or liquids
• Enclosed in a nonintact building 2_
• Site lightly vegetated or lightly covered with a 2_
a nonwater dust-suppressing fluid. Much exposed
soil or liquids
• Slope average less than 10 degrees 2
• Substantially surrounded with mesh fence 2
• Site substantially devoid of vegetation. Large 3
percentage of exposed soil or liquids
• Other 0
Gas Containment:
• Enclosed in an intact building 1
• Enclosed in a nonintact building 2
• Other 0
162
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TABLE B-3 (Continued)
Combine the two containment values as follows:
Level of Gas Containment
0 1 2 3
Level of 0: 0 1 23
Particulate 1:1 1 2 3
Containment 2: 2 2 2 3
3: 3 3 33
163
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TABLE B-3 (Continued)
MATRIX PROCEDURE 3
LANDFARM/LANDTREATMENT
Evaluate the site separately for the following containment factors:
Particulate Containment (choose applicable characteristic with
lowest value):
• Site covered with an essentially impermeable cover 0_
or heavily vegetated. No exposed soU or liquids
(e.g., paved-over)
• Site substantially vegetated or covered with a 1_
nonwater—based dust-suppressing fluid. Little
exposed soil or liquids
• Site lightly vegetated or lightly covered with a 2_
nonwater dust-suppressing fluid. Much exposed soil
or liquids
• Slope average less than 10 degrees 2_
• Substantially surrounded with mesh fence 2
• Site substantially devoid of vegetation. Large
percentage of exposed soil or liquids 3
• Other 0
Gas Containment:
• Synthetic cover with soil cover over 0.4 inches 0
• Soil cover in excess of one inch; soil resistant 1
to gas migration
• Soil cover in excess of one inch; soil not resistant 2
to gas migration
• Other 0
164
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TABLE B-3 (Continued)
Combine the two containment values as follows:
9
Level of Gas Containment
Level of
Particulate
Containment
0:
1:
2:
3:
0
0
1
2
3
1
1
1
2
3
2
2
2
2
3
3
3
3
3
3
165
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TABLE B-3 (Continued)
MATRIX PROCEDURE 4
LANDFILL
Evaluate the site separately for the following containment factors:
Particulate Containment (choose applicable characteristic with
lowest value):
• Site covered with an essentially impermeable cover 0
or heavily vegetated. No exposed soil or liquids
(e.g., paved-over)
• Site substantially vegetated or covered with a
nonwater based-dust-suppressing fluid. Little
exposed soil or liquids 1
• Site lightly vegetated or lightly covered with a 2
nonwater dust-suppressing fluid. Much exposed soil
or liquids
• Slope average less than 10 degrees 2
• Substantially surrounded with mesh fence 2
• Site substantially devoid of vegetation. Large 3
percentage of exposed soil or liquids
• Other 0
Gas Containment:
• Functioning gas collection system 0
• Depth to waste at least six inches; soil cover 1
resistant to gas migration
• Depth to waste at least six inches; soil cover not 1
resistant to gas migration ——
• Nonfunctioning gas collection system 3
• Other 0
166
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TABLE B-3 (Continued)
Combine the two containment values as follows:
Level of Gas Containment
0123
Level of 0: 0 1 23
Particulate 1:1 1 2 3
Containment 2: 2 2 2 3
3: 3 3 33
167
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TABLE B-3 (Continued)
MATRIX PROCEDURE 5
SPILL SITE
Evaluate the site separately for the following containment factors:
Particulate Containment (choose applicable characteristic with
lowest value):
• Site covered with an essentially impermeable cover 0_
or heavily vegetated. No exposed soil or liquids
(e.g., paved-over)
• Enclosed in an intact building 1_
• Site substantially vegetated or covered with a 1_
nonwater-based-dust suppressing fluid. Little
exposed soil or liquids
• Enclosed in an nonlntact building 2_
• Site lightly vegetated or lightly covered with a 2_
nonwater-dust-suppressing fluid. Much exposed soil
or liquids
• Slope average less than 10 degrees 2
• Substantially surrounded with mesh fence 2
• Site substantially devoid of vegetation. Large 3_
percentage of exposed soil or liquids
• Other 0_
Gas Containment:
• Synthetic cover with soil cover over 0.4 inches 0
• Covered with an intact synthetic cover; surface 1
contamination
• Soil cover in excess of one inch 1
• Covered with a nonlntact synthetic cover; surface 2
contamination
• Other 0
168
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TABLE B-3 (Continued)
Combine the two containment values as follows:
Level of Gas Containment
0123
Level of 0: 0 1 23
Particulate 1:1 1 2 3
Containment 2: 2 2 2 3
3: 3 3 33
169
-------
TABLE B-3 (Continued)
MATRIX PROCEDURE 6
WASTE PILE
Evaluate the site separately for the following containment factors:
Particulate Containment (choose applicable characteristic with
lowest value):
• Site covered with an essentially impermeable cover 0_
or heavily vegetated. No exposed soil or liquids
(e.g., paved-over)
• Enclosed in an intact building 1_
• Site substantially vegetated or covered with a 1_
nonwater-based-dust-suppressing fluid. Little
exposed soil or liquids
• Enclosed in an nonlntact building 2_
• Slope average less than 10 degrees 2_
• Substantially surrounded with mesh fence 2_
• Site lightly vegetated or lightly covered with a 3
nonwater-dust-suppressing fluid. Much exposed soil
or liquids
• Site substantially devoid of vegetation. Large 3_
percentage of exposed soil or liquids
• Other 0_
Gas Containment: ,
• Covered with an intact synthetic cover 1
• Covered with a nonintact synthetic cover 2
• Enclosed in an intact building 2
• Other 0
170
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TABLE B-3 (Concluded)
Combine the two containment values as follows:
Level of Gas Containment
Level of
Particulate
Containment
0:
1:
2:
3:
0
0
1
2
3
1
1
1
2
3
2
2
2
2
3
3
3
3
3
3
171
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B.2.6 Alternate Release Potential Algorithms
Options 1 and 1A use an algorithm to evaluate a site's release
potential that combines values based on three emission source
descriptors using probabilistic combinatorics. In Option 2, the
single emission source descriptor that best describes the entire
site is chosen and the site evaluated accordingly, considering size,
mobility, and containment. Numerous alternate algorithms were
considered as follows:
• Assign a minimum nonzero value (e.g., 5) to each site
lacking an observed release.
• Choose the emission source descriptor with the highest
overall value considering descriptor values, size, mobility
and containment.
• Choose all the applicable emission source descriptors and
sum the resulting values, considering size, mobility and
containment, using the minimum of this sum and 45 as the
site value.
• Choose all the applicable emission source descriptors and
sum the resulting values, considering size, mobility and
containment, truncating the sum of the size dependent
emission source descriptor and mobility values to 15 before
multiplying by the containment value. The minimum of this
sum and 45 would be the site value.
These options were rejected in favor of the probabilistic
combinatorics since the latter approach better reflects the
probabilistic nature of the potential-to-release option. A
potentially viable alternative, however, may be to use two rather
than three emission source descriptors.
172
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B.3 Targets Category Options
These options envision alterations in the target distance limit
used in the HRS, currently four miles. As stated previously, the
actual target distance limit is yet to be chosen for Options 1 and 2,
pending completion of a special analysis. The options are listed in
Tables B-4 through B-ll. Further options can be defined employing a
minimum value of 3 (for example).
B.4 Alternate Air Pathways
A total of six complete air pathway options were developed and
presented to EPA for consideration. Four of these options were
rejected in favor of the two options presented in Section 3. The
remaining options are simplifications of the first two. Successive
simplifications were made in the release category addressing
emission source descriptors, containment factors, and mobility
factors. The waste characteristics and targets categories were
unchanged from Option 1. These four options are summarized in
Table B-12.
173
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TABLE fl-4
ALTERNATE POPULATION-AT-RISK FACTOR MATRIX
(Variation 1)
Distance (miles)
Population 0-50 0-15 0-4 0-1
1,
1
101
001
3,001
1,
3,
10
Popi
1
101
001
001
10,
0 6666
- 100 6 9 12 15
- 1,000 9 12 15 18
- 3,000 12 15 18 21
- 10,000 15 18 21 24
,000+ 18 21 24 27
TABLE B-5
ALTERNATE POPULATION-AT-RISK FACTOR MATRIX
(Variation 2)
Distance (miles)
ilation 0-15 0-4 0-1 0-1/2
0 6666
- 100 9 12 15 18
- 1,000 12 15 18 21
- 3,000 15 18 21 24
- 10,000 18 21 24 27
000+ 21 24 27 30
0-1/2
6
18
21
24
27
30
174
-------
TABLE B-6
ALTERNATE POPULATION-AT-RISK FACTOR MATRIX
(Variation 3)
Distance (miles)
Population
1
101
1,001
3,001
10
0
- 100
- 1,000
- 3,000
- 10,000
,000+
0-15
6
6
9
12
15
18
0-4
6
9
12
15
18
21
0-1
6
12
15
18
21
24
0-1/2
6
15
18
21
24
27
0-1/4
6
18
21
24
27
30
175
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TABLE 3-7
ALTERNATE VALUES FOR LAND USE
(Variation 1)
ASSIGNED VALUE -
Distance (miles) to
Commercial/Industrial
Distance (miles) to Nat./
State Parks, Forests
Wildlife Preserves
and Residential Areas
Distance (miles) to
Agricultural Lands:
Ag Land
Prime Ag Land
Distance to Historic/
Landmark Sites
0
5+
10+
5+
10+
1-5 1/2-1
5-10 2-5
1-5
5-10
1/2 - 1
2-5
0 - 1/2
0-2
0 - 1/2
0-2
3, if within view of site or if site is
subject to significant impacts.
176
-------
TABLE B-8
ALTERNATE VALUES FOR LAND USE
(Variation 2)
ASSIGNED VALUE -
Distance (miles) to
Commercial/Industrial
Distance (miles) to Nat./
State Parks, Forests
Wildlife Preserves
. and Residential Areas
Distance (miles) to
Agricultural Lands:
Ag Land
Prime Ag Land
Distance to Historic/
Landmark Sites
0
5+
15+
5+
15+
1-5 1/2-1
10-15 5-10
0 - 1/2
0-5
1-5
10 - 15
1/2 - 1
5-10
0 - 1/2
0-5
3, if within view of site or if site is
subject to significant impacts.
177
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TABLE B-9
ALTERNATE VALUES FOR SENSITIVE ENVIRONMENT
(Variation 1)
ASSIGNED VALUE -
STANCE (MILES) TO
TLANDS
Coastal
Fresh Water
STANCE (MILES) TO
5+
2+
2+
2 -
1/2 -
1 -
5
2
2
1 -
1/4 -
1/2 -
2
1/2
1
0 -
0 -
0 -
1
1/4
1/2
CRITICAL HABITAT
TABLE B-10
ALTERNATE VALUES FOR SENSITIVE ENVIRONMENT
(Variation 2)
ASSIGNED VALUE -
STANCE (MILES) TO
TLANDS
Coastal
Fresh Water
STANCE (MILES) TO
1+
1/4+
1/2+
1/2 - 1
100 ft - 1/4
1/4 - 1/2
0 -
0 -
0 -
1/2
100 ft
1/4
CRITICAL HABITAT
178
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TABLE B-ll
ALTERNATE VALUES FOR SENSITIVE ENVIRONMENT
(Variation 3)
ASSIGNED VALUE - 1 2 3
DISTANCE (MILES) TO
WETLANDS
Coastal 2+ 1-2 0-1
Fresh Water 1/2+ 1/4 - 1/2 0 - 1/4
DISTANCE (MILES) TO 1+ 1/2-1 0 - 1/2
CRITICAL HABITAT
179
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TABLE B-12
OVERVIEW OF IMPORTANT FEATURES OF REJECTED AIR PATHWAY OPTIONS
Release
Category
00
o
Waste
Characteristics
Targets
Option 3
Seven-level observed
release
5 descriptors
Size not included
Mobility* factor
(3 measures)
(5 contaminants)
Simplified gas
containment
Probabilistic
combinatorics
Combined toxicity-
mobility factor
Waste quantity
Population
Sensitive environment
Land use
Based on a to-be-
determined distance
limit
Option A
Five-level observed
release
5 descriptors
Size not included
Mobility* factor
(3 measures)
(5 contaminants)
Simplified gas
containment
Probabilistic
combinatorics
Combined tozicity-
mobility factor
Waste quantity
Population
Sensitive environment
Land use
Based on a to-be-
determined distance
limit
Option 5
Five-level observed
release
5 descriptors
Size not included
Mobility factor not
included
Simplified gas
containment
Probabilistic
combinatorics
Combined toxicity-
mobility factor
Waste quantity
Population
Sensitive environment
Land use
Based on a to-be-
determined distance
limit
Option 6
Five-level observed
release with a
nonzero minimum
value for potential
to release
Combined toxicity-
mobllity factor
Waste quantity
Population
Sensitive environment
Land use
Based on a to-be-
determined distance
limit
•Applicable to gases only.
under investigation.
Particulates are assumed to be mobile. Particulate mobility is currently
-------
APPENDIX C
STEP-BY-STEP INSTRUCTIONS AND EXAMPLES
This appendix provides step-by-step instructions for using
Option 1, including worksheets to facilitate calculations.
Substantially the same instructions are used for all of the options.
The differences lie primarily in the tables and worksheets used.
Many of the required tables can be found in Sections 4 and 5, as
applicable. Additional tables can be found in Appendix D.
This appendix also included two examples illustrating the
application of Options 1 and 2 to a hypothetical wastes site.
C.I Step-By-Step Instructions
This section provides step-by-step instructions for evaluating
a site using Option 1.
Step 1; For each CERCLA contaminant detected in the ambient
atmosphere, calculate the ratio between the concentration detected
in the site samples and the concentration detected in the background
samples.* If the background samples are below the detection limit,
then the detection limit should be substituted for the background
concentration. Select the CERCLA contaminant with the greatest
*These instructions are based on the use of the ratio of background
to site sample concentrations. As stated in Section 4, a similar
approach can be developed using the difference between the
concentrations. A discussion of the use of differences in
determining an observed release can be found in Brown, 1986.
181
-------
ratio ^s the reference conta-nlaan'- and record its Chemical Abstracts
Service (CAS) code, the concentrations detected, and the detection
limit on Worksheet 1: Observed Release Worksheet (Table C-l). If
the ratio of the site sample concentration to the background sample
concentration is above 10.J, assign an observed release value of 45.*
If the ratio is above 1.5 and suppressive conditions prevailed during
sampling, assign an observed release value of 45. Assign a potential
to release value of 0. Record the release values on Worksheet 1 and
go to Step 9. Otherwise, record an observed release value of 0 on
Worksheet 1 and go to Step 2.
Step 2; Select up to three emission source descriptors from
the list of emission source descriptors (Table 9) that apply to
the site and record the codes for the descriptors selected on
Worksheet 2: Potential to Release Worksheet (Table C-2). If more
than three apply, select the three that best describe the site.
Calculate the size of the areas described by the selected
descriptors, including only those applicable areas which contain
waste materials. In general, the areas covered by the descriptors
selected must be larger than the minimum size in the "Small" size
category. If this constraint cannot be met, then select only the
descriptor whose size is greatest relative to the minimum size in
its "Small" category. Emission source descriptor definitions are
*The reader is reminded that tne values of 10 and 1.5 used in Step 1
are provided for illustrative purposes only.
132
-------
TABLE C-l
WORKSHEET 1:
OBSERVED RELEASE WORKSHEET
Units
REFERENCE CONTAMINANT CAS NUMBER
MLMIMUM DETECTION LEVEL
BACKGROUND CONCENTRATION
SITE SAMPLE CONCENTRATION
RATIO
VALUE (0 or 45)
183
-------
TABLE C-2
WORKSHEET 2:
POTENTIAL TO RELEASE WORKSHEET
Mobility
Descriptor Value Value Sum Containment Product
Code Size (A) (B) (A+B) Value (C) t(A+B)zC]
(1)
(2)
(3)
(4) (1)+ (2)+ (3)
(5) (1) x (2) / 45
(6) (1) x (3) / 45
(7) (2) x (3) / 45
(8) (1) x (2) x (3) /2025
(9) (4) - (5) - (6) - (7) + (a)
(10) Potential to Release Value*
*Round-off to nearest whole number.
Descriptor Code: From Table 9.
Size: From Table 11.
Des. Value: From Table 13.
Mooility Value: From Worksheet 5.
Containment Value: From Worksheet 6.
164
-------
provided in Appendix D (Table D-l). Using the table of size ranges
(Table 11), record the sizes selected on Worksheet 2. Determine the
emission source descriptor values from the emission source descriptor
table (Table 13) and record the values on Worksheet 2.
Step 3; Calculate the gas mobility as follows. For each
emission source descriptor, determine up to five contaminants
identified at the applicable portion of the site from the list of
CERCLA contaminants. Contaminants whose locations on the site were
not determined cannot be used to evaluate mobility for any descriptor.
Record the CAS codes for the identified contaminants on Worksheet 3:
Gas Mobility Worksheet (Table C-3). Using the information provided
in the gas mobility tables (Table 15), assess the mobility of each
contaminant and record the results on Worksheet 3. For R.CRA wastes
and contaminants, the information required can be found in Versar,
1984. Standard references such as Weast, 1977 contain information on
vapor pressure and Henry's constants for other contaminants. Versar,
1984 describes the derivation of the dry relative soil volatility
index. Supplemental information on PCBs can be found in Burkhard,
Andren and Armstrong; 1985a, 1985b.
Step 4; Calculate the particulate mobility value as follows.
Estimate the threshold wind speed for the site as indicated in
Cowherd et al., 1985, or use the default value of 12.5 meters per
second. Record the appropriate value as indicated on Worksheet 4:
Particulate Mobility Worksheet (Table C-4). Identify the airport
185
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TABLE C-3
WORKSHEET 3:
GAS MOBILITY WORKSHEET
First Emission Source Descriptor Code
CAS Number VP Value AQ Value RS Value Sum
(1)
(2)
(3)
(4)
(5)
(6) Average of positive values in lines 1 through 5
(7) Gas Mobility Value for First Emission Source
Descriptor (see table below)
Second Emission Source Descriptor Code
CAS Number VP Value AQ Value RS Value Sum
(1)
(2)
(3)
(4)
(5)
(6) Average of positive values in lines 1 through 5
('/) Gas Mobility Value for Second Emission Source
Descriptor (see table below)
VP Value:From Table 15.
AQ Value: From Table 15.
RS Value: From Table i5.
186
-------
(1)
(2)
(3)
(4)
(5)
TABLE C-3 (Concluded)
Third Emission Source Descriptor Code
CAS Number VP Value AQ Value RS Value
(6) Average of positive values in lines 1 through 5
(7) Gas Mobility Value for Third Emission Source
Descriptor (see table below)
Sum
GAS MOBILITY FACTOR TABLE
Range of Average Value
Greater than
or equal to Less than
0
3
5
7
3
5
7
10
Value
0
1
2
3
VP Value: From Table 15.
AQ Value: From Table 15.
RS Value: From Table 15.
187
-------
TABLE C-4
WORKSHEET 4:
PARTICULATE MOBILITY WORKSHEET
Weather Station:
Threshold wind speed8: meters per second (ut)
Fastest Precip. Temp.b
Month Mile (F) (P) (T) (T-10) P/(T-lO) [P/(T-lO)]10/9
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Sum = Sum
divide by 12 x 115
u D PE Index -
188
-------
TABLE C-4 (Concluded)
Mobility Index (I) = (u+ - ut)/PE2
Particulate Mobility Value (4 - log-,0I)c
aDefault value of 12.5 may be used.
^Methodology is valid in the temperature range 28.5 to 90.0 degrees
Fahrenheit. If average monthly temperature is below 28.5 degrees,
set T-10 equal to 18.5. If average monthly temperature is above
90.0 degrees, set T-10 equal to 80.0.
cRound off to nearest whole number. If logio1 exceeds 4, value = 0.
If log10I is less than 0.5, value = 3. The following table provides
alternate, equivalent way to determine the particulate mobility value.
ALTERNATE PARTICULATE MOBILITY VALUE TABLE
Range of Values for I Value
Less than 3.16 x 10~4 0
3.17 x 10~4 - 3.16 x 10~3 1
3.17 x 10~3 - 3.16 x 10~2 2
_2
Greater than 3.16 x 10 3
189
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closest to the site and listed in the Local Climatological Data
Summary. Calculate the average of the monthly fastest miles recorded
at that airport as indicated on the worksheet. Calculate the PE Index
as indicated on the worksheet or as estimated from Figure 2. Record
the PE Index as indicated. Combine these three estimates as indicated
and record the particulate mobility value.
Step 5; Record the gas mobility values for each emission source
descriptor as indicated on Worksheet 5: Combined Mobility Worksheet
(Table C-5). Record the particulate mobility value (assumed to be
the same for each descriptor) as indicated on the worksheet.
Calculate the combined mobility values for each descriptor using the
table on the worksheet and record the values as indicated and on
Worksheet 2.
Step 6: Evaluate the gas and particulate containment aspects of
the site corresponding to the selected emission source descriptors
using the lists of gas and particulate containment factors (Tables D-3
and D-4). If more than one containment descriptor corresponds to the
selected emission source descriptor, select the one that best applies.
Record the containment values for each descriptor on Worksheet 6:
Containment Worksheet (Table C-6).
Step 7; Combine the site containment values using the combined
containment factor matrix (Table 20) and record the results on
Worksheet 6 and Worksheet 2.
190
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TABLE C-5
WORKSHEET 5:
COMBINED MOBILITY WORKSHEET
Descriptor
Code
Gas Mobility
Value*
Particulate Mobility Combined
Value** Value
(1)
(2)
(3)
COMBINED MOBILITY FACTOR MATRIX
Gas Mobility Value
0123
0: 0 1 23
1: 1 2 34
2: 2 3 45
Particulate
Mobility
Value
3:
*From Worksheet 3.
**From Worksheet 4.
191
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TABLE C-6
WORKSHEET 6:
CONTAINMENT WORKSHEET
First Descriptor Code
Particulate Containment Code
Gas Containment Code
Second Descriptor Code
Particulate Containment Code
Gas Containment Code
Third Descriptor Code
Particulate Containment Code
Gas Containment Code
Descriptor Particulate Containment Gas Containment Combined
Code Value Value Value
(1)
(2)
(3)
Descriptor Code: From Table 9.
Particulate Containment Code: From Table D-3.
Gas Containment Code: From Table D-4.
Combined Value: From Table 20.
192
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Step 8; Combine the values calculated previously as indicated
on Worksheet 2. This step concludes the calculation of the potential
to release value.
Step 9; Select up to five contaminants identified at the site
and calculate the toxicity value as indicated in the Tables 4, 6,
and 7 of the HRS User's Manual (47 FR 31219-31243). Record these
values on Worksheet 7: Toxicity-Mobility Worksheet (Table C-7).
Evaluate the mobility of the contaminants as follows. If the
contaminant has been identified as being emitted from the site in an
observed release, its mobility value is set equal to 3. If the
contaminant has not been identified as part of an observed release,
then its mobility value is assessed differently. Mobility values
for particulate contaminants that have not been identified as being
emitted from the site are evaluated using the particulate mobility
factor discussed previously. The mobility value for a nonemitted
gaseous contaminant is calculated as the average of its vapor
pressure, Henry's constant and dry relative soil volatility values
according to Table 15. The mobility value for a contaminant present
as both a gas and a particle is the greater of the applicable gas
and particle mobility values. Combine the toxicity and mobility
values as indicated on the combined toxicity-mobility factor matrix
(Table 22). Record the highest contaminant toxicity-mobility value
as indicated.
193
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TABLE C-7
WORKSHEET 7:
TOXICITY-MOBILITY WORKSHEET
Toxicity Mobility
CAS Number Value Value
Combined
Value
(1)
(2)
(3)
(4)
(5)
(6) Maximum Combined Value
Level of
Toxicity
COMBINED FACTOR MATRIX
Level of Mobility
0 1 _2 _3
0: 0 0 00
1: 0 2 46
4 8 12
2:
3:
12 18
VP Value: From Table 15.
AQ Value: From Table 15.
RS Value: From Table 15.
Toxicity Value: From MRS User's Manual.
194
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Step 10; Record the Observed Release Value (Worksheet 1),
Potential to Release Value (Worksheet 2) and Toxicity-Mobility Value
(Worksheet 7) as indicated on Worksheet 8: Summary Air Route Score
(Table C-8).
Step 11; Evaluate the hazardous waste quantity as indicated in
the HRS User's Manual (47 FR 31219-31243) and record the result on
Worksheet 8.
Step 12; Add lines 3 and 4 on Worksheet 8 as indicated to
determine the waste characteristics value.
Step 13; Evaluate the targets, as indicated in the HRS User's
Manual (47 FR 31219-31243) employing the effective source radius, as
applicable. Add lines 7, 8, and 9 as indicated.
Step 14; Calculate the air migration route score as indicated
on Worksheet 8, lines 11 and 12.
C.2 Hypothetical Examples; The Clean River Site
This section presents a hypothetical example of the application
of Options 1 and 2. It is adapted from the Clean River problem
currently used in HRS training. It is intended to be realistic but
the data do not represent a known hazardous wastes site.
C.2.1 Description of the Site
The site is a closed chemical manufacturing facility that
was in operation between 1945 and 1968. It was engaged in the
manufacture of a wide variety of organic and inorganic chemicals.
The facility is located on 20 acres of mostly low-lying land with a
195
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TABLE C-8
WORKSHEET 8:
SUMMARY AIR ROUTE SCORE
1. OBSERVED RELEASE VALUE8
2. POTENTIAL TO RELEASE VALUEb
3. TOXICITY-MOBILITYC
4. HAZARDOUS WASTE QUANTITY*1
5. WASTE CHARACTERISTICS VALUE (Lines 3 + 4)
6. TARGETS
7. Population
8. Land Used
9. Sensitive Environment
10. TARGETS VALUE (Lines 7+8+9)
11. If line 1 is not equal to 0.0,
multiply lines 1 x 5 x 10
If line 2 is not equal to 0.0,
multiply lines 2 x 5 x 10
12. Divide line 11 by 351 S
aFrom Worksheet 1.
bFrom Worksheet 2.
cFrom Worksheet 7.
dFrom HRS User's Manual.
a
196
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few hills of low elevation along the Clean River, as depicted in
Figure C-l. The Clean River flows through the southwest section of
Charles County, and into Union Lake, before reaching the Major River.
Charles County is approximately 50 square miles in area and includes
the incorporated cities of Catsville and Maryville.
A large portion of the area in Charles County is undeveloped
land. This undeveloped land consists mainly of agricultural and
marsh land (more than 5 acres) along the Clean River, and also
includes some wooded areas. The agricultural land and marsh land
are within 1,000 feet of the site fence, but the wooded areas are at
least 5 miles away from the site.
The developed land is divided among residential and industrial
use. Both residential and industrial areas are concentrated in
Catsville (population 2,957) and Maryville (population 5,258). Near
the site there are many privately owned farms which cultivate
vegetable crops with the nearest farm house located approximately
1,000 feet from the site fence (Figure C-2). A new subdivision of
50 houses, called River View Estates, was built in 1980 approximately
one mile from the site fence along Suburban Road (Figure C-2).
Construction of 100 additional houses is planned over the next
three years. The chemical manufacturing facility has recently been
purchased by a housing developer and the old plant is slated for
demolition.
197
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Key:
D Sediment Sampling Location
• Surface Water Intake
Catsvllle
n
t
\
r
Scale
2 Miles
Irrigation
Pond
Charles County
FIGURE C-1
CLEAN RIVER SITE LOCATION
198
-------
Key:
A Monitoring Well
IN
t
Scale
1/8
1/4 Miles
Farm
House
Farm
House
River View Estimates
<50 Houses)
FIGURE C-2
CLEAN RIVER SITE PLAN
199
-------
The site investigation team found several disposal areas on the
site. A discussion with the previous owners of the facility revealed
that processing wastes were disposed of on the site. In particular,
the off-specification products and undesirable by-products of the
processes were disposed of in an abovegrade landfill (30 percent
slope) along the Clean River (Figure C-2). The landfill has not
been maintained and signs of erosion are everywhere. When a storm
came through the area in late 1979, the Clean River flooded and a
section of the landfill was eroded away, leaving a portion of the
waste in the landfill exposed. The land was purchased by the housing
developer in 1980, but the present owner did not take any measures
to secure the landfill from further erosion. An examination of the
site map reveals that the landfill measures about 245 x 245 feet or
about 60,000 square feet.
In addition, wastes of an unspecified origin were disposed of
In two settling ponds. The ponds are approximately 125 feet in
diameter and 2-1/2 feet deep. The site investigation team also
located an underground tank (between Buildings B & C), and a drum
storage area located near the landfill. The underground tank has a
capacity of 50,000 gallons and was half full at the time of the
investigation. The drums were allegedly removed in 1975 by the
former owners.
The site Investigation team also found 67 drums in various
degrees of decay inside Building B, with liquid oozing from some of
200
-------
the drums and contaminating the grassy area behind the building, but
the team did not locate any liner or containment structure in the
grassy area upon searching.
A summary of the sampling results from the site investigation
is provided in Table C-9. Samples taken around the top perimeter of
the landfill showed concentrations of arsenic and cadmium, while
leachate from the south toe showed high concentrations of arsenic,
phenol, toluene and benzene. Wet sludge samples (50 percent water)
from the ponds showed concentrations of heavy metals including
arsenic and cadmium as well as benzene. A sampling of the contents
of the tank revealed toluene and phenol as its contents. A sample
of the liquid found leaking from the drums inside Building B
indicated the presence of phenol and toluene. The various detection
limits were all less than one part per million.
C.2.2 Step-by-Step Application of the Option 1 Methodology
This section illustrates the step-by-step application of the
Option 1 air pathway evaluation method to the hypothetical Clean
River site. The step numbers corresponds directly to the steps in
Section C.I.
Step 1 (Observed Release Value); No air monitoring was
conducted on the site, hence an observed release value of 0 is
assigned (see Table C-10).
Step 2 (Emission Source Descriptor Values); The following
Option 1 emission source descriptors can potentially be used in
scoring this site:
201
-------
TA3LE C-9
SUMMARY OF SAMPLING RESULTS. CLEAN RIVER SITE
(ppm)
Location
Landfill
Cover Soil
Background
Soil
Leachate
Sludge
Drum Liquid
Arsenic
41
15
120
200
ND
Cadmium
19
ND
ND
150
ND
Phenol
ND
NA
250
ND
750
Toluene
ND
NA
350
ND
1550
Benzene
ND
NA
990
0.1
ND
NA: Not available.
ND: Not detected.
202
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TABLE C-10
CLEAN RIVER EXAMPLE
WORKSHEET 1: OBSERVED RELEASE WORKSHEET
Units
REFERENCE CONTAMINANT CAS NUMBER
MINIMUM DETECTION LEVEL
BACKGROUND CONCENTRATION
SITE SAMPLE CONCENTRATION
RATIO
VALUE (0 or 45) 0
203
-------
• flelowground Tanks—5
• Contaminated Surface Soil: Background below analytical
detection limit; contamination level above analytical
detection limit—10
• Exposed Drums: Drums broken—11
• Landfill: All other situations—20
• Surface Impoundment: Wet; evidence of waste contamination
near surface—26
The principal consideration in selecting a descriptor is whether
there is evidence that hazardous materials have been placed in the
area covered by the selected descriptor. The sampling data and site
investigation Indicated that hazardous materials have been found, or
were known to be disposed of, in the tanks, drums, landfill and
ponds. The materials have either been disposed of on the surface or
have migrated to the surface.
The acceptability of the belowground tanks and exposed broken
drums is straightforward. The contaminated surface soil is
acceptable given the increased cadmium soil level in the cover soil
of the landfill. The fact that cadmium was found in the soil on the
landfill and not in the landfill would indicate that the cover soil
is contaminated with a material other than that disposed of in the
landfill. Hence, it can be considered a separate source, distinct
from the landfill.
No information is provided on the presence of biodegradable
material in the landfill, hence the selection of that descriptor.
204
-------
The wet surface impoundment descriptor was selected for the ponds
reflecting the water content of the sludge samples and the presence
of contaminants in the sludge.
The sizes of the areas covered by each descriptor also meet the
minimum size requirements:
• Belowground Tanks: 50,000 gallons or about 7,000 cubic feet
• Contaminated Surface Soil: About 245 x 245 feet or about
60,000 square feet
• Exposed Drums: 67 drums
• Landfill: About 245 x 245 feet or about 60,000 square feet
• Surface Impoundment: 125 in diameter x 2.5 feet in-depth
each or about 61,000 cubic feet in total
Of the applicable descriptors, the following three descriptors
best describe the site:
• Contaminated Surface Soil: Background below analytical
detection limit; contamination level above analytical
detection limit—10
• Landfill: All other situations—20
• Surface Impoundment: Wet; all other situations—26
The use of the exposed, broken drum descriptor in place of any
of these three would be acceptable. The use of the underground tank
descriptor, while acceptable, would not be indicated since its
containment value would be 0.
The size data indicated that the landfill and ponds would be
considered "medium" while the contaminated surface soil would be
considered "small". The resulting values are listed on Table C-ll.
205
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TABLE C-ll
CLEAN RIVER EXAMPLE
WORKSHEET 2: POTENTIAL TO RELEASE WORKSHEET
Des. Mobility
Descriptor Value Value Sum Containment
Code Size (A) (B) (A+B) Value (C)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
20
26
10
(1)H
(1)
(1)
(2)
(1)
(4)
M 3 4 7 3
M 7 4 11 3
S 6 1 7 3
H (2H (3)
x (2) / 45
x (3) / 45
x (3) / 45
x (2) x (3) /2025
- (5) - (6) - (7) + (8)
Potential to Release Value*
Product
[(A+B)rC]
21
33
21
75
15.4
9.8
15.4
7.19
41.59
42
*Round-off to nearest whole number.
Descriptor Code: From Table 9.
Size: From Table 11.
Des. Value: From Table 13.
Mobility Value: From Worksheet 5 (Table C-14).
Containment Value: From Worksheet 6 (Table C-15).
206
-------
Step 3 (Gas Mobility Value); An examination of the site
information shows that the landfill contains three potentially
gaseous contaminants; phenol, toluene and benzene, while the surface
impoundment contains only one; benzene. The area covered by the
contaminated surface soil descriptor shows no gaseous contaminants.
The gas mobility value for the contaminated surface soil, therefore,
is 0. The following values for the three identified gaseous
contaminants were calculated using Table 15 and Versar, 1984:
• Phenol (CAS Number 00108-95-2);
- VP value: 2
- AQ value: 1
- RS value: 2
• Toluene (CAS Number 00108-88-3);
- VP value: 3
- AQ value: 3
- RS value: 3
• Benzene (CAS Number 00071-43-2);
- VP value: 3
- AQ value: 3
- RS value: 3
Phenol, toluene and benzene can be used to evaluate the gas mobility
factor for the landfill, while benzene can also be used in the
evaluation for the surface impoundments. The gaseous mobility values
for each descriptor are, therefore, as follows (see Table C-12):
Landfill~3, Surface Impoundment—3, Contaminated Surface Soil—0.
207
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TABLE C-12
CLEAN RIVER EXAMPLE
WORKSHEET 3: GAS MOBILITY WORKSHEET
First Emission Source Descriptor Code 20
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
CAS Number VP Value AQ Value
00108952 2 1
00071432 3 3
00108883 3 3
Average of positive values in lines 1
Gas Mobility Value for First Emission
Descriptor (see table below)
Second Emission Source Descriptor
CAS Number VP Value AQ Value
00071432 3 3
RS Value
2
3
3
through 5
Source
Code 26
RS Value
3
Average of positive values in lines 1 through 5
Gas Mobility Value for Second Emission Source
Descriptor (see table below)
VP Value:From Table 15.
AQ Value: From Table 15.
RS Value: From Table 15.
Sum
5
7.7
•(•BM^MMH
3
Sum
9
208
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TABLE C-12 (Concluded)
Third Emission Source Descriptor Code 08
CAS Number VP Value AQ Value RS Value Sum
(1)
(2)
(3)
(4)
(5)
(6) Average of positive values in lines 1 through 5
(7) Gas Mobility Value for Third Emission Source 0
Descriptor (see table below)
GAS MOBILITY TABLE
Range of Average Value
Greater than
or equal to Less than Value
030
351
5 7 2
7 10 3
VP Value: From Table 15.
AQ Value: From Table 15.
RS Value: From Table 15.
209
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Step 4 (Particulate Mobility Value); The Charles County Airport
is the closest weather station to the site that is listed in the
Local Climatological Data Annual Summaries (LCD). The applicable
data for this airport taken from the LCD are given in Table C-13.
The default threshold friction velocity of 12.5 was employed since
the site investigation does not provide the data needed to calculate
a site-specific value. The average of the monthly fastest miles is
40.25 miles per hour or 17.99 meters per second. The PE index for
the site is 90. This results in a Particulate Mobility Index of
-4
6.78 x 10 . Using the equation for the partlculate mobility
value results in a value of 1 for the site (see Table C-13). This
value also applies to any particulate contaminant in calculating the
toxicity-mobility value for that contaminant.
Step 5 (Combined Mobility Value): The gas and particulate
mobility values are recorded on Worksheet 5 (Table C-14) and the
combined mobility values for each descriptor calculated as
indicated.
Step 6 and Step 7 (Containment Values); The site description
indicates that the landfill cover has been eroded and that waste
material is exposed to the atmosphere. Also, the slope of the
landfill is estimated to be 30 percent. Thus, the particulate
containment descriptor LF05P: "Site substantially devoid of
vegetation with a large percentage of exposed soil or waste-bearing
liquids. No other cover. Facility slope greater than 10 degrees
210
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TABLE C-13
CLEAN RIVER EXAMPLE
WORKSHEET 4: PARTICULATE MOBILITY WORKSHEET
Weather Station:
Charles County Airport
Threshold wind speeda:
Fastest Precip.
Month Mile (F) (P)
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
40
30
47
46
41
41
43
45
46
40
31
33
2.83
2.64
3.43
3.14
3.62
4.23
3.75
4.16
3.26
3.01
2.99
3.29
12
Temp.b
(T)
31.4
33.6
42.4
43.3
62.4
70.7
75.5
74.3
67.4
55.3
44.8
35.1
.5 meters per secc
(T-10)
21.4
23.6
32.4
33.3
52.4
60.7
65.5
64.3
57.4
45.3
34.8
25.1
P/CT-10)
0.1322
0.1119
0.1059
0.0725
0.0691
0.0697
0.0573
0.0647
0.0568
0.0664
0.0859
0.1311
jnd (ut)
[P/(T-10)]10/9
0.1056
0.0877
0.0825
0.0542
0.0513
0.0518
0.0417
0.0477
0.0413
0.0491
0.0654
0.1046
Sum = 483
divide by 12
u+ - 40.25
17.99 meters per second
Sum
0.7829
x 115
PE Index = 90
211
-------
TABLE C-13 (Concluded)
Mobility Index (I) - (u+ - ut)/PE2 6.78 x 10
Particulate Mobility Value (4 - log10Dc 1
aDefault value of 12.5 may be used.
Methodology is valid in the temperature range 28.5 to 90.0 degrees
Fahrenheit. If average monthly temperature is below 28.5 degrees,
set T-10 equal to 18.5. If average monthly temperature is above
90.0 degrees, set T-10 equal to 80.0.
cRound off to nearest whole number. If logiQl exceeds 4, value " 0.
If log^o1 is less than 0.5, value " 3. The following table provides
alternate, equivalent way to determine the particulate mobility value.
ALTERNATE PARTICULATE MOBILITY VALUE TABLE
Range of Values for I Value
-4
Less than 3.16 x 10 0
3.17 x 10~4 - 3.16 x 10~3 1
3.17 x 10~3 - 3.16 x 10"2 2
Greater than 3.16 x 10 3
212
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TABLE C-14
CLEAN RIVER EXAMPLE
WORKSHEET 5: COMBINED MOBILITY WORKSHEET
(1)
(2)
(3)
Descriptor
Code
20
26
08
Gas Mobility
Value*
3
3
Particulate Mobility
Value**
Combined
Value
4
4
1
COMBINED MOBILITY FACTOR MATRIX
Particulate
Mobility
Value
Gas Mobility Value
0 ill
0: 0 123
1:1 234
2: 2 345
3: 3 455
*From Worksheet 3.
**From Worksheet 4.
213
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was selected as the best containment descriptor. The value for this
descriptor is 3. Similarly, since the waste material is exposed,
tne gas containment descriptor LF15G: "Waste uncovered or exposed"
was selected as the best gas containment descriptor. The value for
this descriptor is 3. Therefore, the combined containment descriptor
value for the landfill is 3 (see Table C-15).
There is little information provided on the state of the ponds.
Since the impoundments do not contain liquids (only a wet sludge
resting at the bottom), the depth of the impoundment can be taken
as the freeboard. Therefore, the impoundment can be considered
"enclosed". The information provided on the impoundment indicates
that the descriptor WSI05P: "Enclosed impoundment; uncovered,
surface completely open to atmosphere" is the best applicable
descriptor. Its value is 3. The best gas containment descriptor
for tne impoundment is WSI05G: "Wet enclosed impoundment; uncovered,
surface completely open to atmosphere" with an associated value of 3.
Therefore, the combined value for the surface impoundment is 3 (see
Table C-15).
The containment descriptors in Option 1 are the same for the
contaminated surface soil descriptors as they are for the landfill
descriptors. There is also little information provided for the
surface of the landfill, the area of known soil contamination.
Given the information provided, except that signs of erosion are
everywhere, the best particulate containment descriptor is LF05P:
214
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TABLE C-15
CLEAN RIVER EXAMPLE
WORKSHEET 6: CONTAINMENT WORKSHEET
First Descriptor Code
Particulate Containment Code
Gas Containment Code
20
LF05P
LF15G
Second Descriptor Code
Particulate Containment Code
Gas Containment Code
26
WSI05P
WSI05G
Third Descriptor Code
Particulate Containment Code
Gas Containment Code
10
LF05P
LF08G
Descriptor Particulate Containment Gas Containment Combined
(1)
(2)
(3)
Code
20
26
08
Value
3
3
3
Value
1
3
_1
Value
3
3
3
Descriptor Code: From Table 9.
Particulate Containment Code: From Table D-3.
Gas Containment Code: From Table D-4.
Combined Value: From Table 20.
215
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"Site substantially devoid of vegetation with a large percentage of
exposed soil or waste-bearing liquids. No other cover. Facility
slope greater than 10 degrees" with an associated value of 3.
Similarly, since the soil type is unknown, the best gas containment
descriptor is LF08G: "Uncontaminated soil cover less than six
inches; cover soil type unknown" with an associated value of 1.
Therefore, the combined containment value for the contaminated
surface soil is 3 (see Table C-15)-
Step 8 (Potential To Release Value); The preceding data are
recorded on Table Oil. This table also illustrates the calculation
of the potential to release value for the site. Thus, the overall
site potential to release value is 42, based on the Option 1
methodology.
Step 9 (Toxicity-Mobility Value): Since none of the
contaminants have been detected in an observed release, the mobility
value for each is calculated using the gas or particulate mobility
value as applicable. Therefore, the mobility values for the gaseous
contaminants are as follows:
• Phenol (CAS Number 00108-95-2): 2
• Benzene (CAS Number 00071-43-2): 3
• Toluene (CAS Number 00108-88-3): 3
Arsenic (CAS Number 07440-37-1) and cadmium (CAS Number 07440-43-9)
would appear as particulates and, therefore, their mobility values
are set equal to the site particulate mobility value of 1.
216
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The HRS (47 FR 31219-31243) indicated the following air
toxicity values for the contaminants:
• Phenol: 3
• Toluene: 2
• Benzene: 3
• Cadmium: 3
• Arsenic: 3
These values and the combined toxicity-mobility values for each
contaminant are indicated in Table C-16. These values indicate that
benzene has the largest combined toxicity-mobility value and thus the
site toxicity-mobility value is 18.
Step 10; The Observed Release Value (Worksheet 1), Potential
to Release Value (Worksheet 2), and Toxicity-Mobility Value
(Worksheet 7) are recorded on Worksheet 8: Summary Air Route Score
(Table C-17).
Step 11 (Waste Quantity Value); The site description provides
the following data pertinent to the calculation of hazardous waste
quantity:
• 67 drums in Building B
• Volume of ponds is about 61,000 cubic feet
• Belowground tank contains about 25,000 gallons of phenol and
toluene
• Contaminated surface area of the landfill is about 60,000
square feet
• All of the above contained hazardous materials
217
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TABLE C-16
CLEAN RIVER EXAMPLE
WORKSHEET 7: TOXICIIY-MOBILITY WORKSHEET
(1)
(2)
(3)
(4)
(5)
CAS Number
00108952
00108883
00071432
07440371
07440439
Toxicity
Value
3
2
3
3
3
Mobility
Value
2
3
3
1
1
Combined
Value
12
12
18
6
6
(6) Maximum Combined Value
18
Level of
Toxicity
COMBINED FACTOR MATRIX
Level of Mobility
0 1 _2 _3
0: 0 0 00
1:0 246
2: 2 4 8 12
3: 4 6 12 18
VP Value: From Table 15.
AQ Value: From Table 15.
RS Value: From Table 15.
Toxicity Value: From HRS User's Manual.
218
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TABLE C-17
CLEAN RIVER EXAMPLE
WORKSHEET 8: SUMMARY AIR ROUTE SCORE
1. OBSERVED RELEASE VALUE3 0_
2. POTENTIAL TO RELEASE VALUEb 42
3. TOXICITY-MOBILITYC 18
4. HAZARDOUS WASTE QUANTITY*1 7
5. WASTE CHARACTERISTICS VALUE (Lines 3+4) 25
6. TARGETS
7. Population 18
8. Land Used 3_
9. Sensitive Environment 3
10. TARGETS VALUE (Lines 7+8+9) 24
11. If line 1 is not equal to 0.0,
multiply lines 1 x 5 x 10
If line 2 is not equal to 0.0,
multiply lines 2 x 5 x 10 25200
12. Divide line 11 by 351 Sa = 71.79
aFrom Worksheet 1.
bFrom Worksheet 2.
cFrom Worksheet 7.
HRS User's Manual.
219
-------
Current practice in the HRS allows the inclusion of the 67 drums and
the once-filled volume of the ponds in computing hazardous waste
quantity.
No information is given in the site description that would allow
the analyst to determine if the material in the tank is available for
migration. Thus, current HRS practice would not allow the inclusion
of the 25,000 gallons in the tank.
Additionally, no information is provided about the volume of the
landfill or the fraction of the volume that is hazardous. Similarly,
data are lacking on the depth (and hence, volume) of the contaminated
soil on the surface of the landfill (although concentration data are
available in this case). Therefore, no hazardous waste quantity can
be associated with either the landfill or the contaminated surface
soil.
Based on these considerations, the total hazardous waste
quantity is 67 drums plus 9,090 drums (the equivalent volume of the
ponds) for a total of 9,157 drums. This yields a waste quantity
value of 7.
Step 12 (Waste Characteristics Value): Add lines 3 and 4 on
Worksheet 8 as indicated to form the waste characteristics value.
Step 13 (Targets Value); Building il and the landfill are the
two identifiable potential sources of air releases that are the
furthest apart (see Figure C-2). The distance between then is
220
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1/4 mile, according to the site map. Thus, the effective source
radius is 1/8 mile or 660 feet.
The map of the site (Figure C-2) indicates that one farmhouse
is located within 3/8 (1/4 + 1/8) miles of the site. No additional
houses lie within 5/8 (1/2 + 1/8) miles of the site. All of
Riverview Estates (50 houses) lies within 1-1/8 (1 + 1/8) miles of
the site, as do the three identified farm houses. The town of
Catsville lies within 4-1/8 miles of the site as does a small portion
of the town of Maryville.
The value for the population residing within 3/8 miles of the
site is 18. The number of people residing within 1-1/8 miles of the
site cannot be determined from the data presented but can be seen to
be undoubtedly less than the 3,001 persons needed to achieve a value
greater than 18. The population of Catsville and the small portion
of Maryville located within 4-1/8 miles of the site is less than the
10,000 persons required to achieve a value greater than 18, as well.
Therefore, the population targets value for this site is 18.
The distance to the nearest wetland is less than 1,000 feet but
may be more than 100 feet (the information provided is not specific).
The wetland lies along the Glean River and is a fresh water wetland.
No critical habitats of Federal endangered species have been
identified near the site. Therefore, the sensitive environment
value is 2.
221
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No national or state parks, forests, or wildlife preserves have
been identified within two miles of the site. No historic or
landmark sites have been identified as being within view of the
site, either.
The nearest residential area is the River View estates, one mile
from the site. Agricultural land has been found within 1,000 feet
of the site but it is unknown whether this land is prime or not.
The distance to the nearest industrial/commercial area is also
unknown. Based on the distance to the nearest agricultural land,
the land use value is 3.
These values are recorded on Table C-17-
Step 14 (Overall Air Pathway Value); Table C-17 illustrates
the calculation of the overall air pathway score of 71.19 for the
Clean River site.
C.2.3 Application of the Option 2 Methodology
The steps taken in evaluating the site using the Option 2
methodology are very similar to those taken in the Option 1
methodology. The principal differences are in the tables of factors
used and the worksheets.
Step 1 (Observed Release Value); No air monitoring was
conducted on the site, hence an observed release value of 0 is
assigned (see Table C-10).
Step 2 (Emission Source Descriptor Values); The following
Option 2 emission source descriptors can potentially be used in
scoring this site:
222
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• Containers—1
• Contaminated Soil—2
• Landfill—4
• Surface Impoundment—5
The justifications for employing these descriptors has been
discussed previously (see Section C.2.2). Note, the descriptor
"containers" can refer to either the underground tanks and the
exposed drums. However, the sources are not similar in containment.
Hence, they must be evaluated separately.
The sizes of the areas covered by each descriptor are as
follows:
• Containers (underground tanks): 50,000 gallons or about
7,000 cubic feet.
• Contaminated Soil: About 245 x 245 feet or about 60,000
square feet.
• Containers (drums): 67 drums.
• Landfill: About 245 x 245 feet or about 60,000 square feet.
• Surface Impoundment: 125 in diameter x 2.5 feet in depth
each or about 61,000 cubic feet in total.
All of the area meet the minimum size requirement and thus can be
used in evaluating the site's potential to release. The values
for the remaining emission source descriptors are indicated on
Worksheet 1: Potential to Release Worksheet (Table C-18).
Step 3 (Gas Mobility Value); The gas mobility values for each
descriptor have been discussed previously and are as follows:
223
-------
TABLE C-18
WORKSHEET 1:
POTENTIAL TO RELEASE WORKSHEET
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
Descriptor
Code
01*
02
04
05
01**
Potential
Des.
Value
(A)
4
7
6
8
4
Mobility
Value
(B)
4
1
4
4
4
Sum
(A+B)
8
8
10
12
8
Containment
Value
(C)
3
3
3
3
1
to Release Value
Product
[(A+B)xC]
24
24
30
36
8
36
*Drums.
**Underground tanks.
224
-------
• Containers—3
• Contaminated Soil—0
• Landfill—3
• Surface Impoundment—3
Step 4 (Particulate Mobility Value); The evaluation discussed
previously indicated that the PE index for the site is 90. Thus,
the particulate mobility value for all descriptors is 1.
Step 5 (Combined Mobility Value); The gas and particulate
mobility values are summed from the applicable mobility factors for
each descriptor, yielding the following results:
• Containers (both types)—4
• Contaminated Soil—1
• Land fin—4
• Surface Impoundment—4
These values are recorded on Worksheet 1 (Table C-18).
Step 6 and Step 7 (Containment Values); Based on the site
investigation and the previous discussion, the containment descriptors
indicated on Worksheet 2; Containment Worksheet (Table C-19) were
selected. The combined containment values were determined using
Table 20 and the results recorded on Worksheet 1 (Table C-18).
Step 8 (Potential To Release Value); The preceding information
is used to determine the potential to release values for each
descriptor. The potential to release value for the site, as a whole,
225
-------
TABLE C-19
WORKSHEET 2:
CONTAINMENT WORKSHEET
First Descriptor Code
Participate Containment Code
Gas Containment Code
Second Descriptor Code
Particulate Containment Code
Gas Containment Code
Third Descriptor Code
Particulate Containment Code
Gas Containment Code
Fourth Descriptor Code
Particulate Containment Code
Gas Containment Code
Fifth Descriptor Code
Particulate Containment Code
Gas Containment Code
Sixth Descriptor Code
Particulate Containment Code
Gas Containment Code
Seventh Descriptor Code
Particulate Containment Code
Gas Containment Code
Eighth Descriptor Code
Particulate Containment Code
Gas Containment Code
C007P
COTF7G
LD04P
LD15G
LD04P
LD15G
SI05P
SI06G
LD11P
LD08G
01
02
04
05
01
226
-------
TABLE C-19 (Concluded)
Particulate Gas
Descriptor Containment Containment Combined
Code Value Value Value
(1) 01 3 3 3
(2) 02 3 1 3
(3) 04 3 3 3
(4) 05 3 3 3
(5) 01 1 1 1
(6)
(7)
(8)
227
-------
is the largest of the calculated values. Thus, using the Option 2
methodology, the site potential to release value is 36.
228
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APPENDIX D
ADDITIONAL TABLES
This appendix presents the additional tables needed to implement
the proposed revision options. The tables include the fundamental
definitions of the emission source descriptors (Table D-l), as well
as the particulate and gas containment factor definitions and values
for both Options 1 and 1A.
229
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TABLE D-l
EMISSION SOURCE DESCRIPTOR DEFINITIONS
Active Fire; A wastes site that is presently burning or smoldering
and, without remedial action, will continue to do so for an extended
period of time.
Belowground Injection; Belowground injection is a liquid waste
disposal method in which the wastes are emplaced belowground using a
bored, drilled, driven, or dug well to a depth significantly below
the surface. The well rigs may or may not be present on the site.
If they are missing evidence of the injection, holes should still be
present. If the disposal method is a dug well, then its depth must
exceed its width, otherwise it is considered to be a surface
impoundment.
Belowground Tank; A tank is any stationary device, designed to
contain an accumulation of waste, which is constructed primarily of
nonearthen materials (such as wood, concrete, steel, or plastic)
which provide structural support. A belowground tank is a tank the
entire surface area of which is situated completely below the plane
of ground level. Belowground tanks are not externally viewable.
The descriptors "Inground or Aboveground Tanks" should be used
whenever the tanks are at least partially exposed.
Contaminated Surface Soil; Contaminated surface soil is soil taken
from the surface of a site that contains detectable concentrations
of a hazardous substance. Evidence that the substance detected is
related to the site must be provided to substantiate use of this
descriptor.
Emission Sources Not Elsewhere Specified; This descriptor refers
to situations not adequately handled by the other descriptors. A
complete, written description of the site must be provided as support
for the decision to use this descriptor.
Exposed Drum Site; A drum is any portable device in which waste is
stored or otherwise handled. An exposed drum site is a site in
which drums are placed or stacked on the surface of the land without
a soil cover. It also covers the situation in which drums are
buried but partially exposed. The individual drums may be broken or
intact. Sites with completely buried drums are considered landfills.
230
-------
TABLE D-l (Continued)
Inactive Aboveground Fire; A wastes site that is located aboveground
and was at one time significantly inflamed but is not presently
burning.
Inground or Aboveground Tanks; A tank is any stationary device,
designed to contain an accumulation of waste, which is constructed
primarily of nonearthen materials (such as wood, concrete, steel, or
plastic) which provide structural support. Any tank situated in
such a manner that the bottom of the tank is at or above the plane
of ground level is considered to be aboveground. A tank is
considered to be inground if its base is to any degree situated
below the plane of ground level and is in direct contact with the
ground (ignoring liners) such that a portion of the tank wall of
tank top is above the ground and a portion of the tank wall is
belowground (not externally viewable).
Landfarm/Landtreatment; Landfarming or landtreatment is a method of
waste disposal in which liquid wastes or sludges are spread over
land and tilled, generally to a depth of about six inches. It also
applies to the shallow (i.e., of insufficient depth) injection of
liquids if the depth of injection exceeded six inches but did not
qualify as belowground injection. The wastes are reduced or
detoxified through a combination of evaporation, volatilization and
microbiological activity. Landfarm/landtreatment areas are
frequently revegetated after the wastes have decomposed. The
distinguishing characteristic of landfarms and landtreatment
facilities is the shallow injection or tilling of the soil. In
those cases where tilling was not performed or when the depth of
injection was less than six inches, the site should be considered a
spill site.
Landfill; A landfill is a manmade or natural hole in the ground,
containing wastes, that has been backfilled with soil either after
or contemporary with the waste disposal, covering the wastes from
view. The landfill may have been formed either by excavating the
hole or by forming earthen walls around a cleared area. The
characteristics of a landfill that distinguish it from an open pit
or a pile are that the wastes must be co-mingled with soil and that
the wastes must be, or have been, covered with soil. Due to
weathering, erosion and similar phenomena, however, once-buried
wastes in a landfill may become exposed, e.g., partially buried
drums. The contents of a landfill may include nearly any or all
types of wastes including buried drums.
231
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TABLE D-l (Continued)
Open Pit; An open pit has many of the characteristics of a landfill,
the critical differences being that the wastes are not necessarily
belowground level, soil is not intentionally co-mingled with the
wastes and the wastes are not intentionally covered with soil. As
a result, the wastes are exposed to the elements, vectors and
scavengers. As in the case of landfills, the contents of an open
pit may include nearly any or all types of wastes. However, for
purposes of scoring, disposed or stored drums are considered
separately (see exposed drum site definition).
Spill Site; A spill site is a site at which a significant amount
(i.e., at least a "reportable quantity") of liquid wastes or sludges
has been intentionally or unintentionally deposited over the ground
and left otherwise untouched. This descriptor also applies to
landfarms/landtreatment facilities where either tilling was not
performed or the wastes were tilled to a depth less than six Inches.
Similarly, this descriptor applies to sites where shallow injection
of wastes to a depth less than six Inches was performed.
Surface Impoundment; A natural topographic depression, manmade
excavation or diked area, primarily formed from earthen materials
(lined or unlined) which was designed to hold an accumulation of
liquid wastes, wastes containing free liquids, or sludges that were
not backfilled or otherwise covered. If the impoundment has been
backfilled, it is considered a landfill. The intention of a surface
impoundment is to provide temporary storage or to allow the deposited
liquid to be treated and rendered harmless in the future or
volatilize and/or evaporate eventually leaving a "dry" residue to be
covered as in a landfill. The distinguishing characteristics of a
surface impoundment are the emphasis on liquid waste and the general
lack of a cover. Two types of surface impoundments are distinguished
in the air pathway: those with exposed liquid (wet) or those at
which the deposited liquid has evaporated, volatilized or leached
(dry). Synonymous terms include lagoon, pond, aeration pit,
settling pond, and tailings pond.
Surface Water Body or Outfall; A surface water body is an open
expanse of water restricted only by natural topography, e.g.,
rivers, lakes, streams, etc. A surface water outfall is the area of
interface between a waste discharge stream and a surface water body.
This descriptor is for use in those situations where water sampling
indicates the presence of volatile compounds in the water.
Waste Pile; Any noncontalnerlzed accumulation of solid, nonflowing
wastes. Waste piles include tailings piles but exclude tailings
ponds.
232
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TABLE D-2
RELATIONSHIP BETWEEN OPTION 1 AND 1A
EMISSION SOURCE DESCRIPTORS
Option 2 Emission
Source Descriptor
Active Fire Site
Belowground/Buried
Containers
Contaminated Soil
Option 1 Emission
Source Descriptor
Dry Surface Impoundment
Inactive Fire Site
Intact Exposed/Aboveground
Containers
Active Fire Site
Belowground Tanks
Contaminated Surface Soil:
• Background at or above
analytical detection limit
- Contamination level at or
below background
- Contamination level above
background but not
significantly above background
- Contamination level
significantly above background
• Background below analytical
detection limit
- Contamination level below
analytical detection limit
- Contamination level above
analytical detection limit
Surface Impoundment:
• Dry; evidence of waste
contamination near surface
• Dry; all other situations
• Spill Site: spill dry
Inactive Aboveground Fire Site:
• Re-ignition expected
• Re-ignition not expected
Inactive Below Ground Fire Site
• Re-ignition expected
• Re-ignition not expected
Exposed Drums: Drums intact
Aboveground or Inground Tanks:
Tanks intact
233
-------
TABLE D-2 (Continued)
Option 2 Emission Option 1 Emission
Source Descriptor Source Descriptor
Landfarm Landfarm/Landtreatment
Belowground Injection
Landfill Landfill:
• With both biodegradable material
and exposed drums
• With biodegradable material but
without exposed drums
• All other situations
Open Pit
Belowground Tanks
Nonintact Exposed/ Exposed Drums: Drums broken
Aboveground Containers: Aboveground or Inground Tanks:
Tanks broken
Wet Surface Impoundment Surface Impoundment:
• Wet; evidence of waste
contamination near surface
• Wet; all other situations
Spill Site: spill wet
Emission Sources Not Surface Water Body or Outfall
Elsewhere Specified Emission Sources Not Elsewhere
Specified
234
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TABLE D-3
OPTION 1 PARTICULATE CONTAINMENT FACTORS
(CHOOSE CHARACTERISTIC THAT BEST APPLIES)
ACTIVE FIRE SITE (AFS01) 3_
BELOWGROUND INJECTION (BGI01) 0_
BELOWGROUND TANKS (see Landfill)
CONTAINERS (Aboveground or Inground Tanks and Exposed Drums)
C001P Intact, sealed containers protected from the 0_
weather by a maintained cover
C002P Intact, sealed containers not protected from 1_
the weather by a maintained cover
C003P Open, unsealed, or nonintact containers; waste 0_
totally covered with an essentially impermeable,
maintained cover
C004P Open, unsealed, or nonintact containers; waste 1_
partially covered with an essentially
impermeable, maintained cover
C005P Open, unsealed, or nonintact containers; 2_
wastetotally covered with an essentially
impermeable, unmaintained cover
C006P Open, unsealed, or nonintact containers; waste 3_
waste otherwise covered or uncovered
C007P Other 1_
CONTAMINATED SURFACE SOIL (see Landfill)
DRY SURFACE IMPOUNDMENT (see Landfill)
EMISSION SOURCES NOT ELSEWHERE SPECIFIED
NES01P Totally covered with a maintained covered
NES02P Partially covered with a maintained covered
NES03P Totally covered with an unmaintained covered
NES04P Partially covered with an unmaintained covered
NES05P Uncovered
NES06P Other
INACTIVE ABOVEGROUND FIRE SITE (see Landfill)
235
-------
TABLE D-3 (Continued)
INACTIVE BELOW GROUND FIRE SITE (see Landfill)
LANDFARM/LANUTREAIMENT (see Landfill)
LANDFILL
LF01P Site covered with an essentially impermeable
and maintained cover or heavily vegetated
with no exposed soil or waste-bearing liquids
(e.g., paved-over)
LF02P Site substantially vegetated or totally covered
with a maintained nonwater-based dust-
suppressing fluid. Little exposed soil or
waste-bearing liquids
LF03P Site lightly vegetated or partially covered
with a maintained nonwater-based dust-
suppressing fluid. Much exposed soil or
waste-bearing liquids
LF04P Site substantially devoid of vegetation with
a large percentage of exposed soil or
waste-bearing liquids. No other cover.
Facility slope less than 10 degrees or unknown
LF05P Site substantially devoid of vegetation with
a large percentage of exposed soil or
waste-bearing liquids. No other cover.
Facility slope greater than 10 degrees
LF06P Totally enclosed in a structurally intact
building
LF07P Partially enclosed in a structurally intact
building
LF08P Totally enclosed in an nonintact building
LF09P Partially enclosed in an nonintact building
LF10P Substantially surrounded with windbreak
(e.g., mesh or other fence, trees, etc.)
LF11P Active fire site
LF12P Other
OPEN PIT (see Landfill)
SPILL SITE
Spill dry (see Landfill)
Spill wet (see Wet Surface Impoundment)
236
-------
TABLE D-3 (Concluded)
SURFACE WATER BODY OR OUTFALL (see Wet Surface Impoundments)
WASTE PILE (see Landfill)
WET SURFACE IMPOUNDMENTS
WSI01P Enclosed* impoundment; impoundment totally
covered with a maintained cover
WSI02P Enclosed impoundment; impoundment totally
covered with an unmaintained cover
WSI03P Enclosed impoundment; impoundment partially
covered with a maintained cover
WSI04P Enclosed impoundment; impoundment partially
covered with an unmaintained cover
WSI05P Enclosed impoundment; uncovered, surface
completely open to atmosphere
WSI06P Nonenclosed impoundment; impoundment totally
covered with a maintained cover
WSI07P Nonenclosed impoundment; impoundment totally
covered with an unmaintained cover
WSI08P Nonenclosed impoundment; impoundment partially
covered with a maintained cover
WSI09P Nonenclosed impoundment; impoundment partially
covered with an unmaintained cover
WSI10P Nonenclosed impoundment; uncovered, surface
completely open to atmosphere
WSI11P Other
*An enclosed impoundment is one with a freeboard exceeding two feet
in height or one that is substantially surrounded by a wall, fence,
trees, or other adequate windbreak.
237
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TABLE D-4
OPTION 1 GAS CONTAINMENT FACTORS
(CHOOSE CHARACTERISTIC THAT BEST APPLIES)
ACTIVE FIRE SITE
AFS01G Active aboveground fire site 3_
AFS02G Active belowground fire site: Uncontaminated* 1_
soil cover in excess of two feet
AFS03G Active belowground fire site: Uncontaminated* 2_
soil cover less than two feet, soil resistant
to gas migration**
AFS04G Active belowground fire site: Uncontaminated* 3_
soil cover less than two feet, soil not
resistant to gas migration**
BELQWGROUND INJECTION (see Landfill)
BELOWGROUND TANKS (see Landfill)
CONTAINERS (Aboveground or Inground Tanks and Exposed Drums)
C001G Intact, sealed containers protected from the 0_
weather by a maintained cover
C002G Intact, sealed containers not protected from 1_
the weather by a maintained cover
C003G Open, unsealed, or nonintact container; waste 0_
totally covered with an essentially impermeable,
maintained cover
C004G Open, unsealed, or nonintact container; 1_
waste partially covered with an essentially
Impermeable, maintained cover
C005G Open, unsealed, or nonintact container; 2_
waste totally covered with an essentially
impermeable, unmaintained cover
*Lacking contrary evidence, covering soils are assumed to be
Uncontaminated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
238
-------
TABLE D-4 (Continued)
CONTAINERS (Concluded)
C006G Open, unsealed, or nonintact container; waste
otherwise covered or uncovered
C007G Aboveground containers; other
CONTAMINATED SURFACE SOIL (see Landfill)
DRY SURFACE IMPOUNDMENTS (see Landfill)
EMISSION SOURCES NOT ELSEWHERE SPECIFIED
NES01G Totally covered with a maintained covered
NES02G Partially covered with a maintained covered
NES03G Totally covered with an unmaintained covered
NES04G Partially covered with an unmaintained covered
NES05G Uncovered
NES06G Other
INACTIVE ABOVEGROUND FIRE SITE (see Landfill)
INACTIVE BELOWGROUND FIRE SITE (see Landfill)
LANDFARM/LANDTREATMENT (see Landfill)
LANDFILL
LF01G
LF02G
LF03G
LF04G
LF05G
Functioning gas collection system
Existing, nohfunctioning gas collection system
Intact synthetic cover plus uncontaminated soil
cover over 0.5 inches in depth*
Totally covered with an intact synthetic cover;
surface soil contaminated*
Totally covered with a nonintact synthetic
cover; surface soil contaminated*
JL_
2
*Lacking contrary evidence, covering soils are assumed to be
uncontaminated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September, 1980.
239
-------
TABLE D-4 (Continued)
LANDFILL (Concluded)
LF06G Uncontaminated soil cover* in excess of six
inches
LF07G Uncontaminated soil cover* greater than one
inch and less than six inches; cover soil
resistant to gas migration**
LF08G Uncontaminated soil cover* less than six inches;
cover soil type unknown
LF09G Uncontaminated soil cover* greater than one
inch and less than six inches; cover soil not
resistant to gas migration**
LF10G Uncontaminated soil cover* less than one inch;
cover soil resistant to gas migration**
LF11G Uncontaminated soil cover* less than one inch;
cover soil not resistant to gas migration**
LF12G Covering soil contaminated* with waste
contaminants at surface and no synthetic
cover between surface and bulk of waste
materials
LF13G Totally enclosed in a structurally intact
building
LF14G Totally enclosed in an nonintact building
LF15G Waste uncovered or exposed
LF16G Other
OPEN PIT (OP01)
SPILL SITE
Spill Dry (see Landfill)
Spill Wet (see Wet Surface Impoundment)
SURFACE WATER BODY OR OUTFALL (see Wet Surface Impoundment)
WASTE PILE (see Landfill)
_1_
3
*Lacking contrary evidence, covering soils are assumed to be
Uncontaminated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL, and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
240
-------
TABLE D-4 (Concluded)
WET SURFACE IMPOUNDMENTS
WSI01G Wet enclosed* impoundment; Impoundment totally 0_
covered with a maintained, essentially
impermeable cover
WSI02G Wet enclosed impoundment; impoundment totally 1_
covered with an unmaintained, essentially
impermeable cover
WSI03G Wet enclosed impoundment; impoundment partially 1_
covered with a maintained, essentially
impermeable cover
WSI04G Wet enclosed impoundment; impoundment partially 2_
covered with an unmaintained, essentially
impermeable cover
WSI05G Wet enclosed impoundment; uncovered, surface 3_
completely open to atmosphere
WSI06G Wet nonenclosed impoundment; impoundment 0_
totally covered with a maintained, essentially
impermeable cover
WSI07G Wet nonenclosed impoundment; impoundment 1_
totally covered with an unmaintained, essentially
impermeable cover
WSI08G Wet nonenclosed impoundment; impoundment 2_
partially covered with a maintained, essentially
impermeable cover
WSI09G Wet nonenclosed impoundment; impoundment 3_
partially covered with an unmaintained,
essentially impermeable cover
WSI10G Wet nonenclosed impoundment; uncovered, surface 3_
completely open to atmosphere
WSI11G Other 1
*An enclosed impoundment is one with a freeboard exceeding two feet
in height or one that is substantially surrounded by a wall, fence,
trees, or other adequate windbreak.
241
-------
TABLE D-5
OPTION 1A PARTICULATE CONTAINMENT FACTORS
(CHOOSE CHARACTERISTIC THAT BEST APPLIES)
ACTIVE FIRE SITE (AFSOl)
BELOWGROUND/BURIED CONTAINERS (see Landfill)
CONTAINERS (Intact Exposed/Aboveground Containers and
Nonlntact Exposed/Aboveground Containers)
C001P Intact, sealed containers protected from the
weather by a maintained cover
C002P Intact, sealed containers not protected from
the weather by a maintained cover
C003P Open, unsealed, or nonlntact containers; waste
totally covered with an essentially Impermeable,
maintained cover
C004P Open, unsealed, or nonlntact containers; waste
partially covered with an essentially
impermeable, maintained cover
C005P Open, unsealed, or nonintact containers; waste
totally covered with an essentially
impermeable, unmalntained cover
C006P Open, unsealed, or nonintact containers;
waste otherwise covered or uncovered
C007P Other
CONTAMINATED SOIL (see Landfill)
DRY SURFACE IMPOUNDMENT (see Landfill)
EMISSION SOURCES NOT ELSEWHERE SPECIFIED
NES01P Totally covered with a maintained covered
NES02P Partially covered with a maintained covered
NES03P Totally covered with an unmaintalned covered
NES04P Partially covered with an unmaintained covered
NES05P Uncovered
NES06P Other
INACTIVE FIRE SITE (see Landfill)
LANDFARM (see Landfill)
242
-------
TABLE D-5 (Continued)
LANDFILL
LF01P Site covered with an essentially impermeable
and maintained cover or heavily vegetated
with no exposed soil or waste-bearing liquids
(e.g., paved-over)
LF02P Site substantially vegetated or totally covered
with a maintained nonwater-based dust
suppressing fluid. Little exposed soil or
waste-bearing liquids.
LF03P Site lightly vegetated or partially covered
with a maintained nonwater-based dust
suppressing fluid. Much exposed soil or
waste-bearing liquids.
LP04P Site substantially devoid of vegetation with
a large percentage of exposed soil or
waste-bearing liquids. No other cover.
Facility slope less than 10 degrees or unknown
LF05P Site substantially devoid of vegetation with
a large percentage of exposed soil or
waste-bearing liquids. No other cover.
Facility slope greater than 10 degrees
LF06P Totally enclosed in a structurally intact
building
LF07P Partially enclosed in a structurally intact
building
LF08P Totally enclosed in an nonintact building
LF09P Partially enclosed in an nonintact building
LF10P Substantially surrounded with windbreak
(e.g., mesh or other fence, trees, etc.)
LF11P Active fire site
LF12P Other
WASTE PILE (see Landfill)
WET SURFACE IMPOUNDMENTS
WSI01P Enclosed* impoundment; impoundment totally
covered with a maintained cover
WSI02P Enclosed impoundment; impoundment totally
covered with an unmaintained cover
JL_
2
3
1
0
-^—-,
1
*An enclosed impoundment is one with a freeboard exceeding two feet
in height or one that is substantially surrounded by a wall fence
trees, or other adequate windbreak. '
243
-------
TABLE D-5 (Concluded)
WET SURFACE IMPOUNDMENTS (Concluded)
WSI03P Enclosed Impoundment; Impoundment partially
covered with a maintained cover
WSI04P Enclosed Impoundment; Impoundment partially
covered with an unmalntalned cover
WSI05P Enclosed Impoundment; uncovered, surface
completely open to atmosphere
WSI06P Nonenclosed Impoundment; Impoundment totally
covered with a maintained cover
WSI07P Nonenclosed impoundment; Impoundment totally
covered with an unmaintained cover
WSI08P Nonenclosed impoundment; Impoundment partially
covered with a maintained cover
WSI09P Nonenclosed impoundment; impoundment partially
covered with an unmaintained cover
WSI10P Nonenclosed impoundment; uncovered, surface
completely open to atmosphere
WSI11P Other
J
3
244
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TABLE D-6
OPTION 1A GAS CONTAINMENT FACTORS
(CHOOSE CHARACTERISTIC THAT BEST APPLIES)
ACTIVE FIRE SITE
AFS01G Active aboveground fire site ;
AFS02G Active belowground fire site: uncontaminated* J
soil cover in excess of two feet
AFS03G Active belowground fire site: uncontaminated* \
soil cover less than two feet, soil resistant
to gas migration**
AFS04G Active belowground fire site: uncontaminated* '.
soil cover less than two feet, soil not
resistant to gas migration**
BELOWGROUND/BURIED CONTAINERS (see Landfill)
CONTAINERS (Intact Exposed/Aboveground Containers and
Nonintact Exposed/Aboveground Containers)
C001G Intact, sealed containers protected from C
the weather by a maintained cover
C002G Intact, sealed containers not protected J
from the weather by a maintained cover
C003G Open, unsealed, or nonintact container; (
waste totally covered with an essentially
impermeable, maintained cover
C004G Open, unsealed, or nonintact container; J
waste partially covered with an essentially
impermeable, maintained cover
C005G Open, unsealed, or nonintact container; /
waste totally covered with an essentially
impermeable, unmaintained covet
C006G Open, unsealed, or nonintact container; ',
waste otherwise covered or uncovered
C007G Aboveground containers; other ;
*Lacking contrary evidence, covering soils are assumed to be
uncontaminated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL, and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
245
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TABLE D-6 (Continued)
CONTAMINATED SOIL (see Landfill)
DRY SURFACE IMPOUNDMENTS (see Landfill)
EMISSION SOURCES NOT ELSEWHERE SPECIFIED
NES01G Totally covered with a maintained covered
NES02G Partially covered with a maintained covered
NES03G Totally covered with an unmaintained covered
NES04G Partially covered with an unmaintained covered
NES05G Uncovered
NES06G Other
INACTIVE FIRE SITE (see Landfill)
LANDFARM (see Landfill)
LANDFILL
LF01G Functioning gas collection system
LF02G Existing, nonfunctioning gas collection system
LF03G Intact synthetic cover plus uncontaminated soil
cover over 0.5 inches in depth*
LF04G Totally covered with an intact synthetic
cover; surface soil contaminated*
LFO.DG Totally covered with a nonintact synthetic
cover; surface soil contaminated*
LF06G Uncontaminated soil cover* in excess of six
inches
LF07G Uncontaminated soil cover* greater than one
inch and less than six inches; cover soil
resistant to gas migration**
LF08G Uncontaminated soil cover* less than six inches;
cover soil type unknown
LF09G Uncontaminated soil cover* greater than one
inch and less than six inches; cover soil not
resistant to gas migration**
*Lack.ing contrary evidence, covering soils are assumed to be
uncontaminated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL, and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-867c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
246
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TABLE D-6 (Continued)
LANDFILL (Concluded)
LF10G Uncontaminated soil cover* less than one inch;
cover soil resistant to gas migration**
LF11G Uncontaminated soil cover* less than one inch;
cover soil not resistant to gas migration**
LF12G Covering soil contaminated* with waste
contaminants at surface and no synthetic cover
between surface and bulk of waste materials
LF13G Totally enclosed in a structurally intact
building
LF14G Totally enclosed in an nonintact building
LF15G Waste uncovered or exposed
LF16G Other
WASTE PILE (see Landfill)
WET SURFACE IMPOUNDMENTS
WSI01G Wet enclosed*** impoundment; impoundment
totally covered with a maintained, essentially
impermeable cover
WSI02G Wet enclosed impoundment; impoundment totally
covered with an unmaintained, essentially
impermeable cover
WSI03G Wet enclosed impoundment; impoundment partially
covered with a maintained, essentially
impermeable cover
WSI04G Wet enclosed impoundment; impoundment partially
covered with an unmaintained, essentially
impermeable cover
*Lacking contrary evidence, covering soils are assumed to be
Uncontaminated. Soil cover contaminants must be attributable to
the underlying waste materials and gaseous in origin.
**USGS soil types GC, ML, CL, and CH. Source: Adapted from
Lutton, R. J., Evaluating Cover Systems for Solid and Hazardous
Wastes, (EPA-530/SW-S67c), U.S. Environmental Protection Agency,
Washington, DC, September 1980.
***An enclosed impoundment is one with a freeboard exceeding two feet
in height or one that is substantially surrounded by a wall,
fence, trees, or o trier adequate windbreak.
247
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TABLE D-6 (Concluded)
WET SURFACE IMPOUNDMENTS (Concluded)
WSI05G Wet enclosed impoundment; uncovered, surface 3_
completely open to atmosphere
WSI06G Wet nonenclosed impoundment; impoundment 0_
totally covered with a maintained, essentially
impermeable cover
WSI07G Wet nonenclosed impoundment; Impoundment 1_
totally covered with an unmalntained,
essentially impermeable cover
WSI08G Wet nonenclosed impoundment; impoundment 2_
partially covered with a maintained,
essentially impermeable cover
WSI09G Wet nonenclosed impoundment; impoundment 3
partially covered with an unmaintained,
essentially impermeable cover
WS110G Wet nonenclosed Impoundment; uncovered, 3_
surface completely open to atmosphere
WSI11G Other 1
248
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