Hazard Ranking System Issue Analysis:
Review of Existing Ranking Systems
MITRE
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Hazard Ranking System Issue Analysis:
Review of Existing Ranking Systems
Stuart A. Haus
Thomas F. Wolfinger
November 1986
MTR-86W180
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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ABSTRACT
This report presents the results of a review of two types of
ranking systems: hazardous waste site ranking systems and chemical
hazard ranking systems. This effort focused on identifying existing
ranking systems for review and then reviewing the identified systems
to determine whether they have features (e.g., parameters,
methodologies) that warrant further evaluation with regard to
possible modifications to the EPA Hazard Ranking System (HRS).
Where further evaluation appears warranted, that evaluation is being
conducted as part of companion studies to this effort, and the
results of the evaluation will be presented in the reports on these
companion studies, rather than in this report. The purpose of this
report is solely to present an overview of the ranking systems that
were reviewed and to identify those features that were deemed to
warrant further study. Twenty-nine waste site ranking systems were
identified and reviewed. Several of those systems contain features
that should be evaluated in companion studies to this effort for
possible adaptation and use in the HRS. Fifty-six chemical hazard
ranking systems were identified. Twenty-four of these should be
further evaluated in the companion toxicity analysis effort.
Suggested Keywords: Chemical Hazard Ranking Systems, Hazard Ranking
Systems, Superfund, Waste Site Ranking Systems
iii
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TABLE OF CONTENTS
Page
LIST OF TABLES vii
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Issue Description 3
1.3 Scope and Approach 4
1.4 Organization of the Report 6
2.0 RESULTS OF THE REVIEW 7
2.1 Waste Site Ranking Systems 7
2.1.1 Status of Each System 7
2.1.2 Pathways Considered by Each System 12
2.1.3 System Features that Warrant Further Evaluation 14
2.2 Chemical Hazard Ranking Systems 27
3.0 REFERENCES 37
APPENDIX AOVERVIEW OF EPA HAZARD RANKING SYSTEM 43
APPENDIX BWASTE SITE RANKING SYSTEMS 49
APPENDIX CCHEMICAL HAZARD RANKING SYSTEMS 155
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LIST OF TABLES
Table Number Page
1 List of Waste Site Ranking Systems Examined 8
2 Migration and Hazard Pathways Reflected in 13
Each System Examined
3 Summary of the Results of the Review of 15
Existing Waste Site Ranking Systems
4 List of Identified Chemical Hazard Ranking 29
Systems
5 Summary of the Results of the Review of 31
Selected Existing Chemical Hazard Ranking
Systems
vii
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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
Since the enactment of CERCLA in 1980, a variety of ranking
systems have been developed to rate the relative threat posed by
hazardous waste sites or by hazardous substances. Some of these
ranking systems may contain features (e.g., parameters,
methodologies) that could be adapted for use in the HRS to address
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some of the issues identified above. Consequently, these ranking
systems need to be examined as a first step in resolving these
issues. Even where the review does not identify features that could
be adapted for use in the IKS, it may still identify some concepts
from these other systems that could be further developed to resolve
various issues.
1.3 Scope and Approach
This paper presents the results of the review of the existing
ranking systems. Two types of ranking systems were examined: waste
site ranking systems and chemical hazard ranking systems. Waste
site ranking systems rank the relative threat (or risk) posed by
waste sites. Chemical hazard ranking systems rank the relative
hazard (or risk) posed by waste streams or individual waste
constituents, considering the environmental media (e.g., air, water)
in which exposure may occur.
The ranking systems to be examined under this effort were
identified primarily through a literature review and also through
contacts with other Federal agencies (e.g., National Oceanic and
Atmospheric Administration, Department of Defense). In addition,
the ten EPA Regional Offices were contacted to identify ranking
T
systems used by the States within each region. As specified in the
work statement, individual States were not surveyed. However, where
a State system was identified by the above review, the State was
contacted if necessary to obtain a description of the system.
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Each identified waste site ranking system has been reviewed to
determine who is using the system, what it is being used for, who
developed the system, and how it both resembles and differs from the
HRS with regard to such features as parameters, methodologies,
procedures, and applications. The objective of this review is to
identify important differences in the features of these systems that
warrant further evaluation with regard to developing options for
possible modification of the HRS.
Where further evaluation of a feature is warranted, that
evaluation is being conducted as part of the companion HRS issue
analysis task appropriate to the specific feature being examined.
For example, parameters or methodologies applicable to the evaluation
of human food chain effects are being examined as part of the effort
to develop a human food chain exposure evaluation methodology.
Therefore, the results of such evaluations are presented in the
appropriate issue analysis report, rather than in this report. The
purpose of this report is solely to present an overview of these
other waste site ranking systems and to identify those features of
the systems that warrant further study.
Since the chemical hazard ranking systems pertain only to one
issue analysis effort (i.e., the development of a more discriminating
HRS toxicity factor), the intent in this report is just to identify
such systems for review under the toxicity issue analysis effort.
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They are not being examined to identify which of their features
warrant further review under the toxicity issue analysis effort.
1.4 Organization of the Report
Section 2 contains the results of the review of the existing
ranking systems, including recommendations on the features of the
existing systems that warrant further evaluation in the other HRS
issue analyses efforts. Section 3 presents the bibliography.
Appendix A provides an overview of the current HRS. Appendix B
contains the summary reviews of 29 existing waste site ranking
systems. Appendix C presents a brief summary of the 56 chemical
hazard ranking systems identified.
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2.0 RESULTS OF THE REVIEW
This chapter presents the results of the review of the existing
ranking systems. The discussion is divided into two sections: the
first addresses waste site ranking systems, the second addresses
chemical hazard ranking systems. The emphasis in the discussion of
waste site ranking systems is on the overall comparison of these
systems to the HRS and the identification of the features of these
systems that should be evaluated further in various HRS issue
analysis tasks. The emphasis in the discussion of the chemical
hazard ranking systems is on the identification of such systems for
further review.
2.1 Waste Site Ranking Systems
Table 1 presents a list of the 29 waste site ranking systems
examined, together with the system acronyms used in this report.
The following sections discuss the current status of each system,
the migration pathways addressed by each system, and the features of
each system that warrant further evaluation.
2.1.1 Status of Each System
This section discusses the current status of the 29 ranking
systems identified in Table 1. Of the 11 Federal ranking systems,
9 are currently being used by Federal agencies and 2 (DRASTIC and
RAPS) are being tested prior to use.
Two of the EPA systems (RCRA Risk-Cost Analysis Model and the
Liner Location Risk and Cost Analysis Model) are being used by EPA
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TABLE 1
LIST OF WASTE SITE RANKING SYSTEMS EXAMINED
FEDERAL WASTE SITE RANKING SYSTEMS
EPA Waste Site Ranking Systems
- DRASTIC
- Liner Location Risk and Cost Analysis Model (LLRCAM)
- RCRA Risk-Cost Analysis Model (WET Model)
Other Federal Waste Site Ranking Systems
- Centers for Disease Control System for Prevention,
Assessment and Control of Exposures and Health Effects
from Hazardous Sites (S.P.A.C.E. for Health)
- National Oceanic and Atmospheric Administration (NOAA)
- Department of Energy Modified Hazard Ranking System (mHRS)
- Department of Energy Remedial Action Priority System (RAPS)
- Department of the Air Force Hazard Assessment Rating
Methodology (HARM)
- Department of the Air Force Hazard Assessment Rating
Methodology (HARM II)
- Department of the Interior Impact Scoring Methodology (ISM)
- Department of the Navy Confirmation Study Ranking System
(CSRS)
STATE WASTE SITE RANKING SYSTEMS
California Public Health Benefit/Cost Ranking System (PHBCRS)
Connecticut (CT)
Illinois Rating Scheme (IRS)
Massachusetts Prioritization of Environmental Risks and
Control Options (PERCO) System
Michigan Site Assessment System (SAS)
New Hampshire (NH)
New Jersey Severity Index (NJ)
New York Human Exposure Potential Ranking Model (HEPRM)
OTHER WASTE SITE RANKING SYSTEMS
Arthur D. Little, Inc. (ADL)
Dames and Moore Rating and Risk Assessment Methodology (RRAM)
Hagerty, Pavoni, and Herr (HPH)
JRB Associates, Inc. (JRB)
The LeGrand System (LeGrand)
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TABLE 1 (Concluded)
OTHER WASTE SITE RANKING SYSTEMS (Concluded)
Monroe County, NY, Monroe County Methodology (MCM)
Olivier! and Eisenberg Assessment Methodology (OEAM)
Phillips, Nathwani, and Mooij Matrix (PNMM)
Rating Methodology Model (RMM)
TRC Environmental Consultants, Inc. Objective Calculation
Procedure (OCP)
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program offices for various regulatory and policy analysis purposes.
The third EPA system, DRASTIC, is currently being tested prior to
being finalized. (Several EPA program offices are also developing
systems that currently include elements of the draft version of
DRASTIC.)
The three Department of Defense systems (HARM, HARM II, and
GSRS) are used to assign priorities to hazardous substance sites for
further study and possible remedial action under the DOD-wide
Installation Restoration Program. The Centers for Disease Control
(CDC) System (S.P.A.C.E. for Health) was developed for use in public
health assessments of hazardous sites. It is used to assign a
priority to a site based on the potential of the site to endanger
human health. NOAA applies its system to sites that have previously
been scored with the HRS. It is used to identify for further review
the areas under NOAA's purview that are threatened by wastes sites.
The DOI system is used to assist in establishing priorities for
addressing problems associated with abandoned mine land, such as
polluted water, subsidence, dangerous highwalls, and flooding due to
clogging of streams by mine sediments. The DOE modified HRS is
currently being used in ranking waste sites at DOE facilities. RAPS
has recently been completed and will soon be tested by DOE, prior to
use in assigning priorities to DOE mixed (e.g., hazardous
nonradioactive and radioactive) waste sites for further study and
possible remedial action.
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Six of the eight State systems examined are currently in use.
A seventh, PERCO, has recently been completed and is currently being
evaluated by Massachusetts for possible implementation. An eighth,
HEPRM, is still being developed for use in New York. Like the
Federal agencies, the States use their systems to rank sites for
further investigation or for remedial action. This is generally
done to supplement the HRS rankings.
In addition to the Federal and State systems, ten systems
developed and/or used by other governmental and nongovernmental
entities were examined. Of these, only two (Monroe County
Methodology and the Olivieri and Eisenberg Assessment Methodology)
are currently known to be in use and are discussed below. Portions
of two other systems (JRB and LeGrand) have, however, been adapted
for use in several other systems that are also currently in use.
For example, factors contained in the JRB system have been adapted
for use in the HRS, HARM, HARM II, and CSRS. Factors contained in
the LeGrand System have been adapted for use in the Connecticut
System and the Olivieri and Eisenberg Assessment Methodology.
The Monroe County Methodology (MCM) is used by Monroe County,
New York to assist in identifying and prioritizing sites that may
contain hazardous substances for further investigation. It is
intended to be used prior to the application of systems, such as the
HRS, that require site inspection data. The Olivieri and Eisenberg
Assessment Methodology is used by the San Francisco Regional Water
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Quality Control Board to rank wastes sites in terms of their
relative potential for ground water contamination.
2.1.2 Pathways Considered by Each System
Table 2 presents an overview of the migration and hazard
pathways addressed in each system. The HRS addresses three migration
pathways and two additional hazard pathways: ground water, surface
water, air, direct contact, and fire and explosion (see Appendix A).
Only two other systems examined (PERCO and HEPRM) address more
pathways, while most of the other systems address fewer pathways.
Five systems also incorporate one or more migration and hazard
pathways not present in the HRS. These pathways include overland
water flow, flooding, toxic vapors, soil ingestion, and aquatic
biota ingestion.
Additionally, one system (HEPRM), and possibly one other (RAPS),
distinguish between migration pathways and modes of exposure by
considering inter-media transfers of contaminants.* (The available
documentation on RAPS does not, however, describe how this is done.)
One other system (HARM II) considers inter-media transfers from
*The term "migration pathway" generally refers to the medium through
which the contaminants in question migrate, e.g., ground water,
surface water, air. In contrast, the term "mode of exposure" refers
to the pathway through which the contaminants enter the human (or
other) body or otherwise effect the environment. Examples of modes
of exposure include ingestion, inhalation, or dermal contact.
Inter-media transfer refers to the movement of a contaminant from
one medium, through an interface, into another medium (e.g.,
volatilization of a substance from contaminated water into the
atmosphere where it may be inhaled).
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TABLE 2
MIGRATION AND HAZARD PATHWAYS REFLECTED IN EACH SYSTEM EXAMINED*
EPA Waste Site Ranking Systems
HRS
DRASTIC
LLRCAM
WET Model
Other Federal Systems
S.P.A.C.E. for Health
NOAA
mHRS
RAPS
HARM
HARM II
ISM
CSRS
State Waste Site Ranking Systems
PHBCRS
CT
IRS
PERCO
SAS
NH
NJ
HEPRM
Other Waste Site Ranking Systems
ADL
RRAM
HPH
JRB
LeGrand
MCM
OEAM
PNMM
RMM
OCP
Ground
Water
X
X
X
X
X
X
X
X
X
NA
X
X
X
X
X
X
NA
NA
X
X
X
X
X
X
X
X
X
X
X
Surface Direct
Water Air Contact
X
X
X
X
X
X
X
X
X
NA
X
X
X
X
X
NA
NA
X
X
X
X
X
X
X X
X
X
X
X
X
NA NA
X X
X
X X
X X
NA NA
NA NA
X X
X
X
Fire and
Explosion Other
X
X
X
NA NA
X
X X
X
NA NA
NA NA
X
X
*A blank indicates that the system does not address that pathway.
system does not consider migration and hazard pathways.
NA means that
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ground water to surface water in counting ground water targets in
those situations where such a transfer is suspected to occur or can
be confirmed. The other systems, including the HRS, either make no
distinctions at all, or implicitly link migration pathways and modes
of exposure. For example, these latter systems consider only the
ingestion of contaminated water for the ground water pathway. No
provision is made, for example, to reflect any inhalation exposure
arising, in part, from the release of volatile substances during
ground water transport or use. At least one recent study (Foster
and Chrostowski, 1986) has indicated that the inter-media transfer
from water to air could pose a threat to individuals for certain
indoor water uses (e.g., showering).
2.1.3 System Features that Warrant Further Evaluation
Table 3 identifies the major characteristics of each waste site
ranking system reviewed (see Appendix B for a more detailed
description). The table also identifies the features of each system
that warrant further evaluation in the other issue analysis
efforts. These include:
Hydrogeologic factors (such as sorption, conductivity, and
type of media).
Food chain and bioaccumulation factors.
Toxicity factors (including carcinogenicity factors).
Population at risk factors.
Site size factors (such as exposed area).
Potential for flooding factors.
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TABLE 3
SUMMARY OF THE RESULTS OF THE REVIEW OF EXISTING WASTE SITE RANKING SYSTEMS
SYSTEM
EPA Waste Site Ranking Systems
DRASTIC
Liner Location Risk
Ana Cost Analysis
Model
RCRA Risk-Cost
Analysis Model
(WET Model)
MAJOR CHARACTERISTICS
Ranks sites based on their hydrogeologic
potential for ground water contamination
Not a risk ranking system
Employs seven hydrogeologic factors
Designed to estimate chronic risks,
cost/risk and cost/effectiveness
implications of different land disposal
technologies
Intended as a policy analysis model, not a
ranking system
Not meant for site-specific comparisons among
facilities
Designed to evaluate risk and cost aspects
of different waste management practices
applied to different waste streams
Intended as a policy analysis model, not
a ranking system
Not meant for site-specific applications
Other Federal Waste Site Ranking Systems
S.P.A.C.E.
(CDC)
for Health
Designed to aid in preventing and controlling
health problems associated with hazardous
sites
Contains a scheme for assigning priorities
to a site based on the of a site potential
to endanger human health
GENERAL CONCLUSIONS
Evaluate four factors not currently
in HRS:
- Aquifer media
- Soil media
- Topography
- Hydraulic conductivity
Not applicable for ranking the
relative threat posed by CERCLA
sites
If sufficient data were available
for CERCLA sites, some of the
modeling approaches embodied in the
system might be applicable to the
development of a risk-based ranking
system
Not applicable for ranking the
relative threat posed by CERCLA
sites
If sufficient data were available
for CERCLA sites, some of the
modeling approaches embodied in the
system might be applicable to the
development of a risk-based ranking
system
Examine concept of using reports
of human health effects at a site in
the ranking of the site
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TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
GENERAL CONCLUSIONS
Other Federal Waste Site Ranking Systems (Continued)
S.P.A.C.E. for Health
(CDC) (Concluded)
NOAA
Modified Hazard
Ranking Syatea
(HRS) (DOE)
Remedial Action
Priority Syatea
(RAPS) (DOE)
Employs four categories:
- Site characteristics
- Exposure potential (for five migration
pathways)
- Potential for human exposure
- Health effects In the population
Method for combining factor scores to derive
site scores is left up to user
Designed to assign priorities, for further
review, to waste sites that threaten
resources under trusteeship of NOAA
Used after HRS ranking has been completed
Not a risk ranking system
Based on three Indices:
- Proximity Index
- Resource Index
- Chemical Index
Identical to HRS except in method used to
evaluate toxlcity factor for radionuclldes
Risk ranking system based on estimated
exposure concentrations and associated
health risks
Addresses four migration pathways:
- Overland flow
- Ground water
- Surface water
- Air
Review Proximity Index and Resource
Index for possible use in food chain
exposure method
Evaluate method used in rating
radlonuclide toxlcity
Review concept of maximum possible
exposure concentration for use in
evaluating waste characteristics
Review migration pathways to Identify
any factors and approaches that could
be adapted for used in HRS
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TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
GENERAL CONCLUSIONS
Other Federal Waste Site Ranking Systems (Continued)
Remedial Action
Priority System
(RAPS) (DOE)
(Concluded)
Impact Scoring
Methodology (DOI)
Hazard Assessment
Rating Methodology
(HARM) (USAF)
Hazard Assessment
Rating Methodology-II
(HARM II) (USAF)
Addresses four types of exposures:
- Dermal
- External radiation
- Inhalation
- Ingestion
Data requirements substantially exceed
those of HRS
Evaluates relative impacts of problems
associated with abandoned mine land
Used to rank sites for further investigation
based on equivalent of Preliminary Assessment
information
Site score is average of three subscores
(receptors, waste characteristics, and
pathways) multiplied by a management practices
score
Pathways score reflects potential for
migration through ground water, surface
water, or flooding
Subscores are not linked, i.e., surface water
receptors may be averaged with ground water
migration potential
Used to rank sites for remedial investigation
Considers two pathways:
- Ground water
- Surface water
Pathway score based on:
- Potential to release
- Human health and ecological hazard
potential
- Population or resource at risk
No further evaluation warranted
Evaluate concepts embedded in the
following HARM factors:
- Potential for flooding
- Surface soil permeability (for
surface water pathway)
- Data quality/confidence
Evaluate human health and ecological
hazard quotient and travel factors
Evaluate use of weighted root-mean-
square algorithm in determining
overall site score
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TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
GENERAL CONCLUSIONS
00
Other Federal Waste Site Ranking Systems (Concluded)
Hazard Assessment
Rating Methodology-II
(HARM II) (USA?)
(Concluded)
Confirmation Study
Ranking System
(CSRS) (USN)
State Waate Site Ranking Systems
Public Health Benefit/ ,
Cost Ranking System
(California)
Connecticut
Subscores produced for appropriate
combinations of factors, e.g., surface water
migration/human health effects
Site score is weighted root-mean-square
of subscores
Nearly Identical to HARM
Primary differences between CSRS and HARM
are in waste characteristics methodology,
waste management practices scoring, and
in use of product rather than average to
calculate overall score
Designed to rank site remedial action
alternatives in terms of benefit/cost
relationships
Benefit is defined as reduction in sum of
HRS site migration, fire and explosion, and
direct contact scores
Designed to classify sites as:
- Posing no hazard
- Requiring further investigation
- Posing an imminent hazard
Sites are classified as posing an Imminent
hazard whenever any of the following
conditions pertain:
- Improperly disposed liquid PCB wastes
- Asbestos that can become airborne
- Improperly disposed pesticides
- Contaminants disposed within 200 feet
of a drinking water supply
Evaluate concepts embedded In the
following factors not included in
HRS:
- Bloaccumulation potential
- Time factors
- Potential for flooding
- Surface soil permeability (for
surface water pathway)
Identical to HRS, except for cost
factor
No further evaluation is warranted
Evaluate concepts embedded In the
sorption, gradient, and thickness
factors
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TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
GENERAL CONCLUSIONS
State Waste Site Ranking Systems (Continued)
Connecticut (Concluded)
Rating Scheme
(Illinois)
Prioritization of
Environmental Risks
and Control Options
(PEKCO) (Massachusetts)
- Possible fire or explosion
- Fish kills
Discharge of hazardous materials to storm
sewers or surface water
Rating system applies only to potential for
ground water contamination, using factors
based on an adaptation of original LeGrand
system (see below)
Screening tool to assist in regional planning
Evaluates relative human health threat posed
by sites from ground water contamination
Four factors are evaluated, each consisting
of several elements:
- Health risk of waste and handling mode
- Population at risk
- Proximity of waste activity to public water
supply wells or potable aquifer
- Aquifer susceptibility
Site score is normalized sum of factors scores
Designed to rank sites based on chronic and
episodic hazards to human health and the
environment, providing a rationale for
allocating remedial action funds
Four pathways are assessed for chronic hazard:
- Air
- Ground water
- Surface water
- Soil/direct contact
Episodic hazards consist of fire and
explosion, toxic vapor, and floods
Basic measure of interest is the population/
resources exposed to "critical" levels of
contamination
Concentration data (at least one sample) for
the site being rated or from sites similar
to the site being rated must be available in
order to rate the site
Evaluate population at risk factor
Other factors not appropriate for
use in HRS
Evaluate four concepts:
- Use of health effects benchmarks
- Use of data from sites similar to
the site being rated
- Use of simplified air dispersion
equations to specify distance
rings for rating the air target
population
- Use of a flooding factor
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TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
State Waste Site Ranking Systems (Continued)
Site Assessment
System (SAS)
(Michigan)
New Hampshire
Multi-pathway ranking system designed to
reflect the relative risk posed by sites
to public health and environmental
resources
Five exposure pathways are reflected:
- Ground water
- Surface water
- Air
- Direct contact
- Fire and explosion
Site score calculated as the square root of the
sum of the squares of the pathway scores
plus a pathway-Independent chemical hazard
score
Pathway score Is the sum of a potential
exposure score and an existing exposure
score
Chemical hazard score Is evaluated based
on the following factors:
- Toxic!ty (acute, aubchronlc, chronic,
ecological and genotoxlclty)
- Bloaccumulatlon potential
- Persistence
- Flammablllty
- Reactivity
- Data uncertainty
System designed to rank hazardous wastes
sites as high, medium, or low priority
All NPL sites are assigned a high priority
System includes factors for carcinogenic
potential and exposure potential
Presumably, the score Is based on the maximum
carcinogenic potential for the substances at
the site
GENERAL CONCLUSIONS
Evaluate the chemical hazard rating
methodology
Evaluate method for scoring
carcinogenic potential
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TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
State Waste Site Ranking Systems (Continued)
Severity Index
(New Jersey)
Human Exposure Potential
Ranking Model (HEPRM)
(New York)
Tool to assist in ranking sites for site
inspections based on data from a preliminary
assessment
Severity index score is product of a waste
characteristics score and an exposure
potential score
Exposure potential considers six exposure
media (e.g., ground water, air, fire/
explosion), population density/sensitive
environments, and observed exposures
Waste characteristics consider toxicity/
persistence, waste quantity, and
containment
System being developed to prioritize sites
for further investigative and remedial
actions based on their potential to impact
human health
Scores developed for 40 potential human
exposure pathways, e.g., ingestion of surface
water
Each exposure pathway score is the product of
four factors
- Chemical factor
- Target factor
- Probability of release factor
- Weighting factor
GENERAL CONCLUSIONS
No further evaluation warranted.
Evaluate the exposure pathways
not already considered in the
HRS, such as soil Ingestion and
aquatic biota Ingestion
-------
TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
GENERAL CONCLUSIONS
State Waste Site Ranking Systems (Concluded)
Human Exposure Potential
Ranking Model (HEPRM)
(Nev York) (Concluded)
NJ
N>
Other Waste Site Ranking Systems
Arthur D. Little, Inc.
Each of the above four factors are based on
other factors which vary according to pathway
being scored
Exposure pathways are grouped into four
media:
- Air
- Soil
- Ground water
- Surface Water
Score for each medium is the sum of
appropriate exposure pathway scores
Site score is sum of the medium scores
Developed as a modification of the MRS
Addresses three pathways: ground water,
surface water, and air
Site score is the sum of the pathway values
Three factor categories are evaluated within
each pathway:
- Health effects
- Waste reaching pathway
- Population exposed
Health effects category is based on toxicity
of the contaminants on the site
"Waste reaching pathway" category is evaluated
based on evidence of release in all pathways
or, alternately, on "route characteristics"
in ground water and surface water pathways
Population exposed category is very similar
to HRS targets category
Overall pathway score is the product of
category values.
ADL system was assessed during the
development of the HRS
No further evaluation is warranted
-------
TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
Other Waste Site Ranking Systems (Continued)
Rating and Risk
Assessment Methodology
(Dames and Moore)
Hagerty, Pavonl, and
Herr System (HPH)
Methodology for Rating
the Hazard Potential
of Waste Disposal Sites
(JRB model or Rating
Methodology Model)
Adaptation of JRB Associates, Inc. methodology
(see below)
Uses same four rating categories, with some
additions and deletions
Each category Is classified as low or high
risk
Overall site classification based on rating
category classifications
Six site classifications ranging from very
low risk to very high risk
Intended to rate potential ground water
Impacts from landfllllng of wastes
System produces two separate rankings
based on:
- Waste characteristics
- Site and target characteristics
Five factors from the PHL model (see Table 5)
are used to rank waste characteristics
Ten factors are used to rank potential of a
landfill to Impact ground water
Consists of 31 rating factors grouped Into
4 areas:
- Receptors
- Pathways
- Waste characteristics
- Waste management practices
Each rating factor Is scored on a scale of
0 to 3 and then multiplied by a factor-
specific multiplier
Overall site score Is normalized sum of
factor scores
GENERAL CONCLUSIONS
No further evaluation warranted
No further evaluation warranted
JRB model was assessed during
the development of the HRS
No further evaluation Is warranted
-------
TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
Other haste Site Ranking Systems (Continued)
The LeGrand Sye ten
(LeCrand)
NJ
C-
Monroe County
Methodology (MCM)
Designed to evaluate the acceptability of a
proposed disposal site based on the
potential for ground water contamination
at the site
Evaluation process provides for human judgment
System produces a vector of site
characteristics
Site characteristics are based on the
following factors:
- Distance between contamination source
and water supply
- Depth to water table
- Water table gradient
- Permeability-sorption
- Confidence in accuracy of results
- Miscellaneous Identifiers
One additional factor is developed based on:
- Degree of aquifer sensitivity (type of
underlying material)
- Degree of contaminant severity (either
source of the waste or type of waste)
Vector adjusted according to a baseline to
form a situation rating
Situation rating is used to qualitatively
assess the probability of contamination and
the degree of acceptability of the site
Intended as an initial step in identifying
and ranking sites for further investigation
Sites are Identified and classified into
six site activity categories:
- Identifiable
- Possible
- Unspecified
- Lagoons
- Auto junkyards and salvage areas
- Suspicious
GENERAL CONCLUSIONS
Evaluate concepts embedded in the
permeability-sorption factor, the
aquifer sensitivity factors and the
water table gradient factor
Evaluate concept for including a
qualitative assessment of the
accuracy of the rating results
Evaluate geologic ranking system
-------
TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
GENERAL CONCLUSIONS
Other Waste Site Ranking Systems (Continued)
Monroe County
Methodology (MCM)
(Concluded)
NJ
Ln
Olivier! and Elsenberg
Assessment Methodology
Geologic ranking Is prepared, based on the
following factors:
- Overburden geology
- Estimated permeability
- Relief/geomorphology
- Depth to ground water
- Ground water gradient
- Bedrock character
- Soil properties
- Texture and behavior
Sites that could Impact nearby wells are
Immediately referred to authorities for
testing
Other sites are assigned a priority using
a matrix for ranking geologic and land use
impact, size, and type of activity
Ranks organic solvent hazardous wastes
sites in terms of relative potential for
ground water contamination
Corresponds to the HRS ground water pathway
Sites are ranked with regard to two areas:
- Site sensitivity
- Contamination severity
Site sensitivity rates the susceptibility
of the site to ground water contamination
using 14 hydrogeologlc and water use factors
in four factor categories based on LeGrand
Contamination severity rates the severity
and potential for release from the site to
contaminate ground water using nine factors
in three factor categories (four of the
factors are based upon the Michigan Site
Assessment System)
Factors warrant further evaluation
-------
TABLE 3 (Continued)
SYSTEM
MAJOR CHARACTERISTICS
GENERAL CONCLUSIONS
Other Waste Site Ranking Systems (Continued)
Olivier! and Eisenberg
Assessment Methodology
(Concluded)
Phillips, Nathwanl, and
Mooij Matrix
(PNM Matrix)
The scores for each factor are summed to
give site sensitivity and contaminant
severity ratings
Overall site scoring method is user specific,
usually taken as sum of factor scores
Designed to rank potential ground water
impacts from the land disposal of wastes
The PNM matrix produces three types of
rankings:
- Waste hazardousness ranking
- Soil-site ranking
- Combined waste-soil-site ranking
Ten factors (four of which are modified
from the PHL model summarized in Table 5)
are used to rank the relative hazardousness
(in ground water) of wastes that might be
land disposed
The six factors not included in the PNL
model that are used to rank waste
hazardousness are:
- Chemical persistence
- Sorption
- Viscosity
- Solubility
- Acidity/basicity
- Waste application rate
Seven other factors (six of which are
modified from the LeGrand Model) and an
infiltration factor are used to rank the
potential of a land disposal site to result
in impacts to ground water
The 17 factors are combined in a matrix to
rank the waste-soil-site Interaction
Factors in PNM matrix are not
adequately defined for inclusion in
the HRS
No further evaluation is warranted
-------
TABLE 3 (Concluded)
SYSTEM
MAJOR CHARACTERISTICS
Other Waste Site Ranking Systems (Concluded)
Rating Methodology Model
Objective Calculation
Procedure (OCP)
Developed based on the JRB model
Designed to evaluate the risk of hazardous
waste sites and to produce a single score
reflecting this risk
Incorporates four types of factors:
receptors, pathways, waste characteristics,
and waste management practices
Scores are determined for each of several
evaluation parameters then multiplied by
weighting factors to form site parameter
scores
These scores are summed and normalized to
form a site score.
Calculation equation designed to estimate
the total risk from a waste site over a
defined time period
Equation reflects the potency of chemicals
released, the relationship between ambient
concentrations of the chemicals and the
Ingestlon/lnhalatlon rates of the chemicals,
population and the exposure concentration
GENERAL CONCLUSIONS
No further evaluation Is warranted
No further evaluation Is warranted
-------
2.2 Chemical Hazard Ranking Systems
As stated earlier, the principal objective in reviewing chemical
hazard ranking systems is to identify systems for more comprehensive
review in the toxicity issue analysis effort (DeSesso et al., 1986).
A total of 56 chemical hazard ranking systems have been identified
and are listed in Table 4.
Fifty-two of these systems were identified from two
comprehensive reviews of chemical hazard ranking systems (Environ
Corporation, 1984 and Hushon and Kornreich, 1984). These two
reviews examined 23 and 34 systems respectively; 5 systems were
duplicated within the two sets of reviews.
To illustrate the different approaches that have been used to
rate chemical hazards among the various systems and to illustrate
the types of systems that are and are not being recommended for
review in the toxicity issue analysis effort, 7 of the 56 identified
systems are briefly reviewed in this report (see Appendix C). The
major characteristics of these 7 systems and the conclusions from
the review are presented in Table 5.
As indicated in Table 5, four of these seven systems should be
evaluated further:
CERCLA Reportable Quantities (RQ)
Clement Associates, Inc.
RCRA Hazardous Waste Scheduling Methodology
Superfund Public Health Evaluation (SPHE) System
28
-------
TABLE 4
LIST OF IDENTIFIED CHEMICAL HAZARD RANKING SYSTEMS
EPA Chemical Hazard Ranking Systems EC* HK I) C
Action Alert System X X
CERCLA Reportable Quantities (RQ) System X
KCRA Hazardous Waste Scheduling Methodology X
Superfund Public Health Evaluation (SPHE) System X
Selected Criteria Processing X
Assessment of Air Emissions from Hazardous Waste Treatment, Storage and Disposal X
The &CRA Risk-Cost Analysis Model XXX
Toxiclty Scoring System Using RIECS Data Base X
Integrated Environment Management Program X
OTS Chemical Scoring System X
Pesticide Manufacturing Air Prloritization X
Index of Exposure X
System for Rapid Ranking of Environmental Pollutants X
TSCA-ITC Scoring System Workshop X
Scoring of Organic Pollutants X
1TC Scoring for Biological Effects X
1TC Scoring for Exposure X
OECD Ecotoxicology Testing Scheme X
Chemical Scoring System Development X
Environmental Scoring of Chemicals X
Ordering of Commercial Chemicals on NIOSH Suspected Carcinogens List X
Other Federal Chemical Hazard Ranking Systems
U.S. Army Hazard Multi-Media Estimating and Ranking Scheme X
U.S. Army System for Setting Priorities for R&D on Army Chemicals X
U.S. Coast Guard X
Consumer Product Safety Commission (CPSC) X
National Science Foundation X
National Cancer Institute X
OTA X
*EC: Reviewed in Environ Corporation, 1984
HK: Reviewed In Hushon and Kornrelch, 1984
B: Also reviewed in Appendix B
C: Reviewed separately in Appendix C
-------
TABLE 4 (Concluded)
Other Federal Chemical Hazard Ranking Systems (Concluded) EC* M £
NIOSH National Occupational Hazard Survey X
NIOSH Identification of High Risk Occupation Groups and Industrial Processes X
State Chemical Hazard Ranking Systems
Alaska X
California X
California Air Resources Board X
Louisiana X
Maryland X
Michigan X X
Rhode Island X
Washington X
Foreign Chemical Hazard Ranking Systems
EEC Ranking Algorithm for Water Pollutants X X
UNEP X
Federal Republic of Germany X
French Ministere de 1'Environment X
Other Chemical Hazard Ranking Systems
Barring Model XX X
Clement Associates X
PHL Model XX X
Chemical Manufacturers Association X
Dow Chemical X
Soap & Detergent Association X
American Paper Institute and National Forest Products Association X
National Paint and Coatings Association X
Weyerhauser Corporation X
Eastman Kodak Company X
ASTM, Committee D-19 X
Flavor and Extract Manufacturer's Association X
Hooker Chemical X
R. Squire X
*EC: Reviewed in Environ Corporation, 1984
HK: Reviewed in Hushon and Kornreich, 1984
B: Also reviewed in Appendix B
C: Reviewed separately In Appendix C
-------
TABLE 5
SUMMARY OF THE RESULTS OF THE REVIEW OF SELECTED EXISTING CHEMICAL HAZARD RANKING SYSTEMS
SYSTEM
Action Alert Systc
(AAS)
Barring Model
CERCLA Reportable
Quantities (RQ) System
MAJOR CHARACTERISTICS
Developed as a preliminary screening tool
for use in assigning priorities to chemicals
for further study or regulatory action based
on the potential risk they pose to humans and
aquatic life, based upon partial Information
about their presence in the environment and
the associated potential hazards
Screening provides either a qualitative
indication of the degree of concern
warranted for each chemical or a specification
of the additional data required to make such a
determination
Designed to Identify a representative list
of hazardous substances and to rank, the
effects of these substances in terms of
air, water, and land pollution hazards
Total effects rating (TER) calculated as
weighted sum of four factor values:
- Toxic effects to human and other populations
- Flammable hazard
- Explosive hazard
- Reactive hazard
Hazard extent rating (HER) based on annual
production and consumer distribution of the
hazardous substances
Hazard rating - TER x HER
Determines the minimum quantity of a
hazardous substance spill or release that
must be reported to EPA under CERCLA
Substance assigned an interim RQ for each for
the following charateristlcs:
- Reactivity
- Ignitabillty
- Acute toxlcity
- Aquatic toxlcity
- Chronic toxlcity
GENERAL CONCLUSIONS
AAS Is not applicable to ranking the
potential threat posed by hazardous
waste sites
No further evaluation Is warranted
Considered in the development of
more recent ranking models
No further evaluation warranted
System should be evaluated further
-------
TABLE 5 (Continued)
SYSTEM
CtRCLA Reportable
Quantities (RQ) System
(Concluded)
U)
Clement Associates, Inc.
MAJOR CHARACTERISTICS
Statutory RQ is minimum of interim RQs adjusted
to account for persistence of the substance
in the environment
Reactivity la evaluated based on the ability
of the substance to react with water and/or
Itself
Ignltabillty Is evaluated based on the flash
point and boiling point of the substance
Acute toxlcity Is evaluated based on the
or LI>50 of the substance administered by
IngestIon, inhalation or dermal contact, as
applicable
Aquatic toxiclty is evaluated using the LC50
of the substance
Chronic toxiclty Is evaluated based on a
overall minimum effective dose (MED) of the
substance and numerical assessment of the
severity of the effects caused by repeated
or continuous expsoure
The methodology provides a score for a
pollutant that represents the relative
probability that a given hazard will occur
in exposed populations per unit dose of the
pollutant
Effects scored for each pollutant are
carclnogeniclty, teratogenicity, reproductive
toxlcity, mutagenlcity, hepatotoxiclty, renal
toxiclty, neurobehavloral toxicity and effects
In other organ systems
The score Is a product of two measures of risk:
- Probability that the pollutant is toxic
to humans, based on inferences from
animal data, or on direct measures of
human toxiclty
- Probability of occurrence of the toxic
effect in exposed humans per unit dose
of exposure, assuming that the agent
is a human toxicant
GENERAL CONCLUSIONS
System should be evaluated further
-------
TABLE 5 (Continued)
SYSTEM
PHL Model
RCKA Hazardous Waste
Scheduling Methodology
U)
Superfund Public Health
Evaluation (SPHE)
System
MAJOR CHARACTERISTICS
Designed to rank the hazardousness of
substances placed in landfills
The model consists of five ranking factors
that are summed:
- Toxicity (based on Sax)
- Ground water toxicity
- Disease transmission potential
- Biodegradability
- Mobility
Computational equations are used to assign
a value to each factor
Ranks the toxic potential of waste constituents
Incorporates measures of both acute and chronic
toxicity:
- LD^Q is used as a measure of acute toxicity
- Chronic toxicity designated as Equivalent
Dose Estimate (EDE)
EDE based on acceptable daily intakes (ADIs)
for noncarcinogens and unit cancer risks
(UCRs) for carcinogens, modified as
necessary by uncertainty factors
For compounds with extremely limited data
bases, EDEs are assigned by analogy to
structurally similar compounds or are
estimated by applying a large standardization
factor to a measure of acute toxicity
Constituent score is the sum of the chronic
toxicity score (0 to 9) plus the acute toxicity
score (1, if acute toxicity is high, 0
otherwise)
Method for estimating the public health
impacts of NPL sites
Method for selecting indicator chemicals was
examined as a chemical hazard ranking system
GENERAL CONCLUSIONS
Considered in the development of
more recent ranking models
No further evaluation is warranted
System should be evaluated further
Approach to deriving toxicity
constants should be evaluated
further
-------
TABLE 5 (Concluded)
SYSTEM
Superfund Public Health
Evaluation (SPUE)
System (Concluded)
MAJOR CHARACTERISTICS
Uses an "Indicator score" to identify Indicator
chemicals; this Is the product of the measured
(or estimated) concentration of the chemical
at the site times a "toxlclty constant" (In
units of Inverse concentration)
Separate toxlclty constants for carcinogenic
and noncarcinogenlc effects
Acute toxlclty not considered
Noncarcinogenlc toxlclty factors based on
quotient of minimum effective dose (MED) and
severity factor (RVe)
Carcinogenic toxlclty constants based on
effective doae to 10 percent of exposed
population
Other factors considered subjectively include:
- Persistence
- Weight of evidence for carcinogenlcity
- Water solubility
- Vapor pressure
- Henry's constant
- Organic carbon partition coefficient
GENERAL CONCLUSIONS
-------
All of these four systems, except the SPHE system, address acute
toxlclty. All but the RQ system address carcinogenic effects. All
four address chronic noncarclnogenlc effects. The RQ system assigns
a relative ranking value to hazardous substances based on several
hazard characteristics including toxicity, reactivity, and
ignitability. The Clement Associates, Inc. system assigns a relative
risk ranking to chemicals that represents the relative probability
that a given hazard (e.g., cancer) will occur in exposed populations
per unit dose of the chemical. The RCRA system ranks chemicals for
acute toxicity based on their LDc0* and for chronic toxicity based
on their acceptable daily intake or unit cancer risk, as applicable.
The SPHE system assigns an indicator score to chemicals based on
chronic toxicity, distinguishing between carcinogens and
noncarcinogens, using a methodology based in part on the RQ system.
(See Appendix C for more details about these systems.)
The other three systems reviewed (Action Alert, Barring Model,
PHL Model) were found not to warrant further study. The Action Alert
System is designed as a planning tool for qualitatively ranking
chemicals for further study or regulatory action based on the
potential risk they pose to humans and to aquatic organisms. It is
not intended to rank the relative hazard of the various chemicals.
The Barring and PHL Models are very early ranking systems that were
*The LD50 represents the dose of a substance that is lethal to
50 percent of the test population.
35
-------
considered in the development of more recent chemical hazard ranking
models and do not warrant any further evaluation.
In addition, 20 of the 23 systems contained in the Environ
Corporation review (1984) warrant further evaluation. The 3 that do
not warrant further evaluation are those 3 discussed above. None of
the 34 systems contained in the Hushon and Kornreich review (1984)
warrant further evaluation. Many of these latter 34 systems are
designed solely as screening tools for use in assigning priorities
to chemicals, especially new chemicals or suspected carcinogens, for
further study. They are not meant for, nor are they applicable to,
rating the relative hazard of chemicals for use in regulatory
programs. Most of the other systems within this set of 34 are
intended to select or identify chemicals for regulation or control
based on such factors as production rates and use patterns.
It should be noted that many of the waste site ranking systems
reviewed in Appendix B also contain factors to rate chemical hazard.
Those systems whose chemical hazard rating factors warrant further
evaluation (e.g., Michigan Site Assessment System, U.S. Air Force
HARM II System) are identified in Appendix B.
36
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Olivieri, A. W. and D. M. Eisenberg, "A Methodology for Ranking Risk
of Groundwater Contamination from Hazardous Material Sites," ASCE
National Conference on Environmental Engineering, Los Angeles, CA,
June 25-27, 1984.
Rothenstein, Cliff, U.S. Environmental Protection Agency,
Washington, DC, personal communication to Carol Burger, The MITRE
Corporation, September 22, 1986.
Roycroft, Dianne, Michigan Department of Natural Resources,
Groundwater Quality Division, personal communication to Thomas F.
Wolfinger, The MITRE Corporation, August 1985.
Seller, L. and L. Canter, Summary of Selected Ground Water Quality
Impact Assessment Methods, National Center for Ground Water Research,
Report No. NCGWR 80-3, Norman, OK, 1980.
Slimak, Mike, U.S. Environmental Protection Agency, Washington, DC,
personal communication to Carol Burger, The MITRE Corporation,
September 18, 1986.
State of Connecticut 208 Program, Hazardous Waste Site Evaluation
Manual, (1076-J80-80), prepared by TRC, Environmental Consultants,
Wethersfield, CT, 1980.
Tennessee Valley Authority and Oak Ridge National Laboratory,
A National Inventory of Abandoned Mine Land Problem; An Emphasis on
Health, Safety, and General Welfare Impacts, prepared for the
Departments of Interior and Energy, 1983.
41
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Thornhill, Jerry, U.S. Environmental Protection Agency, Ada, OK,
personal communication to Carol Burger, The MITRE Corporation,
September 19, 1986.
U.S. Environmental Protection Agency, DRASTIC; A Standardized
System for Evaluating Ground Water Pollution Potential Using
Hydrogeologic Settings, (EPA-600/2-85/018), Robert S. Kerr
Environmental Research Laboratory, Ada, OK, May 1985.
U.S. Environmental Protection Agency, Liner Location Risk and Cost
Analysis Model, (Draft Report), U.S. Environmental Protection
Agency, January 1985.
U.S. Environmental Protection Agency, An Approach to Prioritization
of Environmental Pollutants; The Action Alert System, Final Draft
Report, U.S. Environmental Protection Agency, June 1980 (revised
January 1982).
Unites, Dennis, Mark Possidento, and John Housman, "Preliminary Risk
Evaluation for Suspected Hazardous Waste Disposal Sites in
Connecticut," 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. 25-29.
Whelan, G. et al., "Development of the Remedial Action Priority
System: An Improved Risk Assessment Tool for Prioritizing Hazardous
and Radioactive-Mixed Waste Disposal Sites," 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. 432-437.
42
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APPENDIX A
OVERVIEW OF EPA HAZARD RANKING SYSTEM
The Hazard Ranking System (HRS) is used by EPA to estimate the
relative potential hazard posed by releases or threatened releases of
hazardous substances. The HRS migration score, which is described
below, is one of the criteria used in determining whether the release
or threatened release should be placed on the National Priorities
List. This appendix presents an overview of the HRS. A more detailed
description appears as Appendix A to the National Contingency Plan
(40 CFR 300) and in the Federal Register (47 FR 31180, July 16, 1982).
The HRS addresses three hazard modes: migration, fire and
explosion, and direct contact. The latter two are not used in
computing the migration site score which is a criteria for placement
on the NPL, 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 route 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,
43
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then an "observed release" has been demonstrated.* If no such
observed 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 A-l.
*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.
44
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TABLE A-l
HRS RATING FACTORS
Route
Factor Category
Ground Water
Surface Water
Air
Release Category
Waste Characteristics
Targets
Monitoring data
or
Depth to aquifer
of concern
Net precipitation
Permeability
Physical state
Containment
Toxicity/persistence
Waste quantity
Ground water use
Distance/population
Monitoring data
or
Facility slope and
terrain
Rainfall
Distance to receiving
water
Physical state
Containment
Toxicity/persistence
Waste quantity
Surface water use
Distance/population
Distance to sensitive
environment
Monitoring data
Reactivity/incompatibility
Toxicity
Waste quantity
Land use
Distance/population
Distance to sensitive
environment
-------
Within each route, 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
scores are produced, each on a scale of 0 to 100. These route
scores are 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 route scores:
Sm = (l/1.73)[(Ssw)2 + (Ssw)2 + (Sa)2]1/2
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 A-l.
46
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Observed Release
0 or 45 pts
OR
Route Characteristics
and Containment*
0-45 pts
Waste Characteristics
GW - 0-26 pts
SW - 0-26 pts
A - 0-20 pts
Targets
GW -
SW -
A -
0-49 pts
0-55 pts
0-39 pts
Pathway Score
0-100 pts
Normalized
' Not Included in Air Pathway
GW = Ground Water Pathway
SW = Surface Water Pathway
A = Air Pathway
FIGURE A-1
BASIC MRS STRUCTURE
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APPENDIX B
WASTE SITE RANKING SYSTEMS
This appendix summarizes 29 systems developed for use in ranking
waste sites. Table 1 in Section 2 lists the systems reviewed. The
summary presented for each system in this appendix contains information
on the following topics:
Name
User
Developer
Use/Status
General Description
Similarities to HRS
Differences from HRS
Conclusions
References
The appendix is divided into four sections:
B.I EPA Waste Site Ranking Systems
B.2 Other Federal Waste Site Ranking Systems
B.3 State Waste Site Ranking Systems
B.4 Other Waste Site Ranking Systems
B.I EPA Waste Site Ranking Systems
This section contains summaries of three EPA ranking systems:
DRASTIC
Liner Location Risk and Cost Analysis Model
RCRA Risk-Cost Analysis Model
49
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DRASTIC
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO MRS:
DRASTIC
Developed for use by the U.S. Environmental
Protection Agency
National Water Well Association
DRASTIC is intended to be used to evaluate
the relative vulnerability of areas to ground
water contamination. A draft version of
DRASTIC was completed in May 1985 and is
currently being tested in 10 counties
nationwide. Several EPA program offices
(e.g., underground storage tanks) have
implemented systems based on the draft
version of DRASTIC.
DRASTIC is designed to evaluate the relative
ground water pollution potential of any
hydrogeologic setting or area. DRASTIC uses
seven rating factors to compute an index (the
DRASTIC Index) which indicates the relative
vulnerability of an area to ground water
contamination. The seven rating factors are
as follows:
Depth to Water (D)
Net Recharge (R)
Aquifer Media (A)
Soil Media (S)
Topography (slope) (T)
Impact of the Vadose Zone (I)
Hydraulic Conductivity of the Aquifer (C)
Each factor is assigned a weight based on its
relative importance with regard to its
pollution potential. The DRASTIC Index is
calculated by multiplying the value assigned
to a rating factor by its weight and summing
the resulting value for the seven factors.
DRASTIC is intended to evaluate relative
ground water pollution potential. As such it
corresponds to the HRS ground water route
characteristics category. Three of the
50
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DRASTIC (Concluded)
SIMILARITIES TO HRS:
(Concluded)
DIFFERENCES FROM HRS:
CONCLUSIONS:
DRASTIC rating factors are similar to factors
present in the HRS ground water route
characteristics category:
Depth to Water
Net Recharge
Impact of Vadose Zone
The scoring and weighting of these factors
differ, however, from the HRS.
DRASTIC is not intended to evaluate the
relative threat posed by a waste site since
it does not consider waste characteristics,
waste containment, or targets. Further,
DRASTIC addresses only the potential for
ground water contamination, ignoring the
potential for surface water, air, and soil
contamination. The following four of the
DRASTIC rating factors do not correspond to
any factors present in the HRS ground water
route characteristics category:
Aquifer Media
Soil Media
Topography
Hydraulic Conductivity of the Aquifer
The rating factors in DRASTIC need to be
further evaluated for possible inclusion in
the HRS.
REFERENCE:
U.S. Environmental Protection Agency,
DRASTIC; A Standardized System for
Evaluating Ground Water Pollution Potential
Using Hydrogeologic Settings,
(EPA-600/2-85/018), Robert S. Kerr
Environmental Research Laboratory, Ada, OK,
May 1985.
Thornhill, Jerry, U.S. Environmental
Protection Agency, Ada, OK, personal
communication to Carol Burger, The MITRE
Corporation, September 19, 1986.
51
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LINER LOCATION RISK AND COST ANALYSIS MODEL
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
Liner Location Risk and Cost Analysis Model
U.S. Environmental Protection Agency, Office
of Solid Waste
Sobotka & Co., ICF, Inc., Environ Corp.,
Pope-Reid Associates, Inc., and Geraghty &
Miller
The model is intended only for internal EPA
use. It is available through the EPA National
Computer Center and is currently being used
by several EPA program offices. Portions of
the model are still being evaluated. The
model also is currently being revised for use
in evaluating municipal landfills.
The Liner Location Risk and Cost Analysis
Model is designed to investigate cost/risk
and cost/effectiveness implications of the
land disposal of hazardous wastes under
different technology, location, and waste
stream scenarios. The model estimates the
relative chronic risk to human health from
land disposal facilities with different
design technology, location, and waste stream
characteristics. The model also estimates
the cost of facilities with differing
technologies and sizes. The model uses a
series of submodels to predict contaminant
releases, subsurface and atmospheric
transport, human exposure, and health risks
based upon dose-response factors. The model
embodies both numerous simplifying
assumptions (e.g., homogeneous and isotropic
aquifers) and generic parameters (e.g.,
generic ground water flow fields, generic
well distances, generic contaminant mobility
classes, generic design technologies).
The Liner Location Risk and Cost Analysis
Model is not similar to the HRS. The only
common characteristics are that both address
waste disposal, relative risk, and two common
pathways (air and ground water).
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LINER LOCATION RISK AND COST ANALYSIS MODEL (Concluded)
DIFFERENCE FROM HRS:
CONCLUSION:
REFERENCES:
There are considerable differences between
the two systems. First, the liner location
model is not a ranking system. It is
primarily a policy analysis model. Second,
it is not meant for site-specific comparisons
among facilities, nor can it be easily
adapted for such site-specific use. Third,
it directly calculates relative risk using a
process modeling approach and some generic
configurations.
The Liner Location Risk and Cost Analysis
Model is not applicable to the task of
ranking CERCLA sites. The approaches
embodied in the model could, however, be
employed in developing a relative risk-based
ranking system, providing sufficient data
for use in such an approach were available
for CERCLA sites.
U.S. Environmental Protection Agency, Liner
Location Risk and Cost Analysis Model,
(Draft Report), U.S. Environmental
Protection Agency, January 1985.
Rothenstein, Cliff, U.S. Environmental
Protection Agency, Washington, DC, personal
communication to Carol Burger, The MITRE
Corporation, September 22, 1986.
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RCRA RISK-COST ANALYSIS MODEL
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
RCRA Risk-Cost Analysis Model, also known as
the WET Model
Economic Analysis Branch, Office of Solid
Waste, U.S. Environmental Protection Agency
ICF Incorporated
Currently used by the EPA Office of Solid
Waste in assessing policies developed under
RCRA.
The WET model is designed to evaluate waste
management practices in the U.S. as an aid
to the development of regulations under
RCRA. The model produces relative risk and
cost estimates for different management
configurations of waste streams; waste
transportation, treatment and disposal
technologies; and environments (hence the
acronym Waste, Environment, ^technology).
The model estimates human health, ecosystem
and sensory risks from steady state releases
of RCRA contaminants (and selected other
contaminants) to ground water, surface water
and air. The model also calculates the
costs of each technology in a management
configuration as an annual revenue
requirement. The model treats each
management configuration in a generic
fashion employing standard risk assessment
methods (e.g., emissions estimates coupled
with transport and fate models aligned with
dose response models) and numerous
simplifying assumptions.
The WET model is not similar to the HRS.
Nearly the only common characteristics is
that both address waste disposal, relative
risk, and the same three pathways.
There are considerable differences between
the two systems. First and most important,
the WET model is not a ranking system. It
54
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RCRA RISK-COST ANALYSIS MODEL (Concluded)
DIFFERENCES FROM HRS: is a policy analysis model. Second, the WET
(Concluded) model is not a site-specific model nor can
it be easily adapted for site-specific use.
Finally, the model apparently assumes that
the generic sites are designed and operated
according to RCRA promulgated or proposed
regulations. Very few CERCLA sites would
fit this assumption.
CONCLUSIONS: The WET model is not applicable to the task
of ranking CERCLA sites. The approaches
embodied in the model could be employed in
developing a relative risk-based ranking
system, providing sufficient data for use in
such an approach were available for CERCLA
sites.
REFERENCES: IGF Incorporated, The RCRA Risk-Cost Analysis
Model Phase III Report, IGF Incorporated,
Washington, DC, March 1, 1984.
IGF Incorporated, The RCRA Risk-Cost Analysis
Model Phase III Report Appendices, ICF
Incorporated, Washington, DC, March 1, 1984.
Males, Eric, "RCRA Risk-Cost Analysis Model,"
Presented at the AIChE Conference held on
August 21, 1984, U.S. Environmental
Protection Agency, Washington, DC, 1984.
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B.2 Other Federal Waste Site Ranking Systems
This section contains summaries of eight systems developed by
Federal agencies other than EPA for use in ranking sites for
investigation and possible remedial action. The systems examined are
as follows:
S.P.A.C.E. for Health (CDC)
National Oceanic and Atmospheric Administration Method
mHRS (DOE)
RAPS (DOE)
HARM (USAF)
HARM II (USAF)
ISM (DOI)
CSRS (USN)
56
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CENTERS FOR DISEASE CONTROL
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
System for Prevention, Assessment, and
Control of Exposures and Health Effects from
Hazardous Sites (S.P.A.C.E. for Health)
Centers for Disease Control (CDC)
Centers for Disease Control
Used by CDC in support of public health
assessments of hazardous sites.
The S.P.A.C.E. for Health system was
developed by CDC to assist State and local
health official in preventing and controlling
health problems associated with hazardous
sites, including hazardous wastes sites.
The system contains a prioritization
scheme. The purpose of the scheme is to
assign a site priority based on the
potential of the site to endanger human
health. The scheme is based on four factors:
site characteristics, exposure potential of
five pathways, potential for human exposure/
absorption, and health effects in the
population. The elements contained in these
factors are listed in the Table B-l. The
method for combining the score for each
element to form a site score is left to the
discretion of the analysts using the scheme.
The scoring of the various elements is
recommended to be done by a team of experts
that includes at a minimum an environmental
specialist, a toxicologist, and a physician
and/or epidemiologist.
Both are value-based systems addressing most
of the same environmental pathways. Both
are designed to make effective use of
available information, without requiring
extensive new information collection.
Several of the elements in S.P.A.C.E. for
Health have been excerpted directly or
adapted from the HRS (e.g., toxicity,
persistence, containment, waste quantity,
ground water, surface water).
57
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TABLE B-l
FACTORS AND ELEMENTS ADDRESSED IN THE S.P.A.C.E FOR HEALTH SYSTEM
FACTORS ELEMENTS
Site Characteristics Documentation of presence of hazardous
substances
Toxicity of five most hazardous substances
at site
Quantity of five most hazardous substances
at site
Persistence of five most hazardous
substances at site
Concentrations of five most hazardous
substances at site
Site management and containment
Potential for direct access to site
Exposure Potential Ground water
of Environmental Surface water
Pathways Air
Deposition in(on) soil off site
Presence in food chain
Potential for Human Presence of potentially exposed population
Exposure/Absorption Basis of evidence for human exposure/
absorption
Levels of substances through biological
sampling
Health Effects in Allegation/reports of health effects
Exposed Population Results of clinical or epidemiologic
studies conducted
Expectation of a currently observable
health effect
Expectation of a future health effect
Severity of public health impact of
presumed health effect
58
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CENTERS FOR DISEASE CONTROL (Continued)
DIFFERENCES FROM HRS:
CONCLUSIONS:
The differences between the two systems are
significant. The most important difference
between the two is that S.P.A.C.E. for Health
makes use of health effects information for
the population exposed around the site in the
rating process. It uses clinical data and
biological sampling data, as well as
allegations/reports of health effects, in the
rating of several elements under both the
potential for Human Exposure/Absorption and
Health Effects in Exposed Population factors.
This type of information is not typically
utilized in the HRS. S.P.A.C.E. for Health
is also a more subjective system than the
HRS, e.g., allegation/reports of health
effects are assigned a score of one even if
they are "vague, nonspecific, poorly
characterized allegations." The system also
depends more on expert judgment as indicated
above. Further, the assessment of threat is
based on five substances present at the site
rather than on one as in the HRS. Finally,
S.P.A.C.E. for Health does not contain an
algorithm to calculate the overall site score
from the element scores; the determination of
the overall score is left to the user's
discretion.
Several of the factors in S.P.A.C.E. for
Health have been derived from the HRS and do
not warrant any further evaluation. However,
the concept of using human health effects
information, particularly observed human
health effects potentially associated with
the site, warrants further evaluation. For
example, the idea embodied in S.P.A.C.E. for
Health of employing alleged and substantiated
health effects information for the surrounding
population to aid in prioritizing sites
should be examined. This type of information
is frequently the spur to site identification
and initial assessment.
59
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CENTERS FOR DISEASE CONTROL (Concluded)
REFERENCES: French, Jean G. et al., A System for
Prevention, Assessment, and Control of
Exposures and Health Effects from Hazardous
Sites (S.P.A.C.E. for Health), Centers for
Disease Control, Atlanta, GA, January 1984.
Kay, Robert L., Jr. and Chester L. Tate, Jr.,
"Public Health Significance of Hazardous
Waste 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. 232-238.
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NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION
SYSTEM:
USER:
DEVELOPER:
USE/STATUS
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCE FROM HRS!
CONCLUSIONS:
Untitled
Ocean Assessments Division, National Oceanic
and Atmospheric Administration (NOAA)
Ocean Assessments Division, NOAA
The system has been applied to sites that
have previously been scored with the HRS.
The purpose is to identify, for further study
by NOAA, those sites that appear to pose a
threat to resources under the trusteeship of
NOAA (as defined by CERCLA).
The system consists of three indices:
Proximity Index, Resource Index, and
Chemical Index. The Proximity Index is a
measure of the frequency with which various
concentrations of contaminants from a site
would reach the resource. The Resource
Index is a measure of the value and extent
of utilization of the marine resource. The
Chemical Index is a measure of the toxicity
and persistence of the most hazardous
substance that could migrate from the site.
The Chemical Index is derived from the HRS
toxicity/persistence factor.
While comparable to the HRS Surface Water
Use Factor, the Resource Index emphasizes
fishery and aquatic habitat uses rather than
the broad range of activities addressed in
the HRS. The Proximity Factor combines data
on the concentration of contaminants in the
resource with data on the frequency of
release (e.g., flooding).
The three indices are not intended to
constitute a hazardous site ranking system.
Rather they are intended to assist in
assigning priorities to previously ranked
sites for further review by NOAA. The
Proximity Index and the Resource Index
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NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (Concluded)
CONCLUSIONS: should be reviewed as part of any development
(Concluded) of a food chain exposure methodology for the
HRS. However, it is unlikely that they would
be adequate for use in the HRS in their
present form.
REFERENCES: Ocean Assessments Division, Office of
Oceanography and Marine Services, National
Ocean Services, National Oceanic and
Atmospheric Administration, Coastal Hazardous
Waste Site Review, April 1984.
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SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
DEPARTMENT OF ENERGY - mHRS
Modified Hazard Ranking System (mHRS)
U.S. Department of Energy (DOE)
Battelle Pacific Northwest Laboratory (PNL)
The mHRS was developed for DOE. It is
currently being used by a number of DOE
facilities to rank the threat posed by waste
sites.
The Modified Hazard Ranking System was
developed by PNL for DOE to address the
concern expressed by DOE that the HRS reflects
only the chemical hazard of radioactive
isotopes and neglects the hazard posed by the
radiation from such isotopes. The mHRS works
within the framework of the HRS dividing the
Waste Characteristics components of the HRS
pathways into two subcomponents for radioactive
and chemical wastes. The chemical wastes
subcomponent of the mHRS is identical to the
HRS waste characteristics component. The
radioactive waste subcomponent is more complex.
To use the mHRS, the analyst identifies the
radionuclides present in the site and
determines their "dose factor group." The
assignment of a radionuclide to a dose factor
group is based on a dose factor calculated
using the ONSITE/MAXI1 program. The dose
factor was calculated separately for each
radionuclide of concern and mode of exposure
(e.g., inhalation and ingestion). If
concentration data are available (pCi/L) for
the radionuclides, the radioactive waste value
is read from a matrix table. The rows reflect
dose factor groups, the columns reflect the
ambient concentration and the entries give the
rankings. If no concentration data are
available, the maximum potential concentrations
are calculated using simplified transport
equations and then are used with the above
table. These equations are used only for the
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DEPARTMENT OF ENERGY - mHRS (Concluded)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS;
CONCLUSIONS:
REFERENCES:
ground water, surface water, direct contact,
and fire and explosion routes. No provision
is made for estimating potential
concentrations for the air route.
The mHRS is designed to be embedded within
the HRS. With the exception of the
radioactive waste characteristics scoring
mechanism, the mHRS is identical to the HRS.
The only difference between the two systems
is the radioactive waste characteristics
scoring mechanism.
The mHRS radioactive waste scoring mechanism
should be evaluated for possible inclusion
in the HRS. Also, the concept of using
simplified transport equations to assess the
maximum possible exposure concentration
should be evaluated.
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 Meeting,
(CONF-841187), held at Albuquerque, NM,
November 6-8, 1984, U.S. Department of
Energy, Washington, DC, April 1985.
Hawley, K. A. and B. A. Napier, A Ranking
System for Sites with Mixed Radioactive and
Hazardous Wastes, (Comment Draft), Battelle
Pacific Northwest Laboratory, Richland, WA,
June 1985.
Katz, Sherry, U.S. Department of Energy,
Germantown, MD, personal communication to
Carol Burger, The MITRE Corporation,
September 18, 1986.
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DEPARTMENT OF ENERGY - RAPS
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
Remedial Action Priority System (RAPS)
Developed for use by the Department of Energy
Battelle Pacific Northwest Laboratory (PNL)
The system has been completed and will be
tested on two facilities in the fall of
1986. Use by DOE facilities is reported to
be anticipated in the spring of 1987.
The Remedial Action Priority System (RAPS)
is designed to assess the risk posed by
mixed (radioactive and nonradioactive
hazardous) waste sites and to prioritize the
sites for further investigation and remedial
action. RAPS employs relatively simple
transport, transformation and fate models to
assess the risks posed to sensitive receptors
by releases of contaminants. Four transport
and transformation pathways are covered in
RAPS: overland water flow, air, surface
water, and ground water. Four additional
modes of exposure are also reflected in the
system: external dermal contact, external
radiation dose, inhalation, and ingestion.
A hazard potential index is calculated for
each pathway reflecting the risks associated
with that pathway. Sites/pathway
combinations are then ranked using
appropriate hazard potential indices. The
site pathway ranks are then combined to form
an overall site rank. The details of these
combinatorics are not discussed in the
available reference documents.
The only important similarity between RAPS
and the HRS is that both address the ground
water, surface water, and air pathways. Of
lesser significance is that both utilize
some of the same data but in different
fashions.
65
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DEPARTMENT OF ENERGY - RAPS (Concluded)
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES:
RAPS is very different from the HRS. RAPS is
expressly designed to assess the relative
risks posed by sites. It employs transport,
transformation and fate models to relate the
characteristics of the site to the risks
posed to receptors of concern. In contrast,
the HRS is a value-based ranking system that
indirectly reflects risk.
RAPS should be reviewed in detail (when its
documentation becomes available) to determine
whether any of the modeling techniques used
in it can be adapted for use in the HRS.
Whelan, G. et al., "Development of the
Remedial Action Priority System: An Improved
Risk Assessment Tool for Prioritizing
Hazardous and Radioactive-Mixed Waste
Disposal Sites," 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. 432-437.
Katz, Sherry, U.S. Department of Energy,
Germantown, MD, personal communication to
Carol Burger, The MITRE Corporation,
September 18, 1986.
66
-------
DEPARTMENT OF THE AIR FORCE - HARM
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
Hazard Assessment Rating Methodology (HARM)
U.S. Air Force (USAF) in the Installation
Restoration Program (IRP)
Jointly developed by the USAF Occupational
Environmental Health Laboratory, Air Force
Engineering Services Center, Engineering
Science, and CH2M Hill
Used to rank sites for follow-up site
investigations and confirmation activities
under Phase II of the IRP.
HARM is a site ranking system designed to
rank sites for priority attention. The
system is designed to use data developed
during the Record Search (Phase I) portion
of the IRP. Record Searches in the IRP are
the near equivalent of the EPA Preliminary
Assessments.
The overall procedure for developing a HARM
site score is illustrated in Figure B-l.
The HARM score is composed of four subscores
reflecting the receptors potentially at
risk, the waste and its characteristics
present at the site, the potential migration
pathways, and waste management practices at
the site.
Table B-2 lists the rating factors and
multipliers used to develop the receptors
score. The overall receptor score is the
normalized sum of the rating factor scores
on a scale of 0 to 100.
The waste characteristics subscore is
calculated as the product of a waste factor,
a persistence factor and a physical state
factor. The waste factor is evaluated using
a matrix approach based on the quantity of
wastes present, the level of confidence in
the information, and the degree of hazard
67
-------
Start
RECEPTORS
WASTE CHARACTERISTICS
Apply
Multiplier
Calculate
Receptor
Subscore
Determine
Waste
Quantity/
Hazard Score
Apply
Persistence
Factor
Apply
Physical State
Factor
Calculate
Waste Char.
Subscore
oo
Other\Flooding
Potential
Pathways,
WASTE MANAGEMENT PRACTICES ,
H
Apply
Containment
Multiplier
Factor
Final
Rating
Score
Source: Engineering-Science, 1983.
FIGURE B-1
HAZARD ASSESSMENT RATING METHODOLOGY FLOW CHART
-------
TABLE B-2
HARM RECEPTOR RATING FACTORS
Rating Factor Multiplier
Population within 1,000 feet of site 4
Distance to nearest well 10
Land use/zoning within 1-mile radius 3
Distance to reservation boundary 6
Critical environments within 1-mile radius of site 10
Water quality of nearest surface water body 6
Ground water use of uppermost aquifer 9
Population served by surface water supply within 6
3 miles downstream of site
Population served by ground water supply within 6
3 miles of site
Source: Engineering-Science, 1983.
69
-------
DEPARTMENT OF THE AIR FORCE - HARM (continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO MRS:
posed by the wastes. The degree of hazard
is the maximum of scores for toxicity,
ignitability and radioactivity.
The pathway score is calculated as the
maximum of a ground water migration potential
score, a surface water migration potential
score, a flooding score, a direct evidence
of migration score, and an indirect evidence
of migration score. The direct or indirect
evidence of migration factors are assigned
scores of 100 or 80, respectively, when
applicable evidence indicates that migration
has occurred. Otherwise, they are assigned
scores of 0. The factors and multipliers
used to evaluate surface water and ground
water migration potential are listed in
Table B-3. Each factor is evaluated on a
scale of 0 to 3 and multiplied by the
appropriate multiplier. The applicable
factor scores are then summed and normalized
to a scale of 0 to 100.
Waste management practices are evaluated
using the following table:
No containment: 1.0
Limited containment: 0.95
Fully contained and fully in
compliance: 0.10
The overall site score is the average of the
receptor score, the waste characteristics
score and the pathways score multiplied by
the waste management practices score.
There are numerous similarities between HARM
and the HRS. Both address ground water and
surface water contamination. Both include
provisions for assessing evidence of releases
as well as potential for releases. Both
also address the characteristics of the
wastes present on the site and the targets
(or receptors) potentially at risk from the
site. Finally, the two systems have many
70
-------
TABLE B-3
HARM PATHWAY POTENTIAL TO RELEASE FACTORS
Rating Factor Multiplier
Surface Water Migration
Distance to nearest surface water 8
Net precipitation 6
Surface erosion 8
Surface permeability 6
Rainfall intensity 8
Ground Water Migration
Depth to ground water 8
Net precipitation 6
Soil permeability 8
Subsurface flows 8
Direct access to ground water 8
Flooding 1
Source: Engineering-Science, 1983.
71
-------
DEPARTMENT OF THE AIR FORCE - HARM (Continued)
SIMILARITIES TO HRS: similar rating factors; however, the specific
(Concluded) criteria for evaluating these rating factors
are somewhat different in the two systems.
The factors that are similar include:
Size of target population
Distance to nearest well
Land use in potentially affected area
Critical environments
Water quality/use
Waste quantity
Contaminant persistence
Physical state of wastes
Distance to receiving stream
Net precipitation
Permeability
Waste containment
Rainfall intensity
DIFFERENCE FROM HRS: Despite their similarities, HARM and the HRS
are very different systems, both in terms of
structure and purpose. Broadly speaking,
the purpose of HARM is to rank sites for
further investigation based on the equivalent
of EPA preliminary assessment data. The HRS
is designed to rank sites for further study
and possible remedial action based on site
inspection data (see also HARM II).
Further, the structures of the two systems
are different. The HRS treats three
migration pathways, evaluating each
separately and then combining the migration
route scores to from an overall site score
using a root-mean-square approach. In
contrast, HARM aggregates receptors and
waste characteristics independent of
migration pathway. Further, HARM addresses
only migration via water pathways (i.e.,
ground water, surface water and flooding)
and does not consider the air migration
pathway. HARM also does not address the
potential for direct contact with waste
materials.
72
-------
DEPARTMENT OF THE AIR FORCE - HARM (Continued)
DIFFERENCE FROM HRS:
(Concluded)
CONCLUSIONS:
HARM also evaluates the overall site score
differently from the HRS. HARM employs
the average of the receptor, waste
characteristics, and pathway scores,
multiplied by the waste management practices,
in contrast to the HRS which multiplies
these scores and normalizes them to form
pathway-specific scores. Overall, HARM
evaluates a site based on the total of all
potential targets, the most hazardous
compound present on the site, the highest
migration route score and the degree of
waste management. Thus, in HARM, a site can
achieve a high score for targets threatened
by ground water contamination, using
contaminants that cannot migrate through the
ground water, based on their potential to
migrate through surface water, modified by
either ground water or surface water
containment practices.
Finally, HARM contains some factors not
included in the HRS:
Potential for flooding
Degree of surface erosion
Subsurface flows (whether the bottom of
site is located in the ground water)
Potential for direct access to ground
water (e.g., fractures, faults, faulty
wall casings)
Surface soil permeability (for the
surface water pathway)
Confidence in data on the wastes and
waste quantity present on site
The concepts embedded in the following HARM
factors should be examined further (the
factors themselves are generally not well
enough defined for use in the HRS):
Potential for flooding
Surface soil permeability
Data quality/confidence
73
-------
DEPARTMENT OF THE AIR FORCE - HARM (Concluded)
REFERENCES: Engineering-Science, Comparison of U.S.
Air Force Hazard Assessment Rating
Methodology (HARM) with U.S. Environmental
Protection Agency Hazard Ranking System
(HRS) at Four Air Force Bases Evaluated
under the Phase I Installation Restoration
Program, Engineering-Science, Atlanta, GA,
April 1983.
Material from unpublished Air Force
briefings.
74
-------
DEPARTMENT OF THE AIR FORCE - HARM II
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
Hazard Assessment Rating Methodology II
(HARM II)
U.S. Department of the Air Force (USAF)
Oak Ridge National Laboratory (ORNL)
HARM II is used by the USAP in their
Installation Restoration Program (IRP) to
assign priorities to sites for follow-up
assessment and field studies.
HARM II has been developed by ORNL as an
extension of the HARM system. It is
designed to make use of site-specific
monitoring data. HARM is not designed to
use such data. HARM II addresses two
exposure pathways; ground water and surface
water. Within each pathway, the site is
assigned a score for potential to release
contaminants (pathway score), human health
and ecological hazard potential (contaminant
hazards scores), and population or resources
at risk (receptor scores). The various
factors used in the scoring are listed in
Table B-4. The system then produces a
subscore for each appropriate combination of
pathway score, contaminant hazards score,
and receptors score, i.e., a surface
water-health pathway score, a surface
water-ecological pathway score, ground
water-health pathway score, and surface
water-ecological pathway score. These
subscores are then combined using a weighted
root mean square algorithm to form the site
score.
The principal similarities between HARM II
and the HRS lie in the pathways common to
both (surface water and ground water) and in
the types of factors addressed by both. The
specific factors used in HARM II are tailored
to the needs of the USAF. The two systems
75
-------
TABLE B-4
HARM II FACTORS
Surface Water
Pathway Score
Contamination Detected
Contamination Not Detected
- Distance to nearest surface water
- Net precipitation
- Surface erosion potential
- Rainfall intensity
- Surface permeability
- Flooding potential
Containment Multiplier
Contaminant Hazards Score: Human Health
Contaminants Detected
- Log of sum of hazard quotients
Contaminants Not Detected (based on single contaminant)
- Toxicity
- Bioaccumulation
- Persistence
Waste Quantity Multiplier
Receptors Score: Human Health
- Population that obtains drinking water from surface water
sources within 3 miles downstream
- Water quality classification of surface water
- Population within 1,000 feet of site
- Distance to nearest installation boundary
- Land use/zoning within 1 mile
Contaminant Hazards Score: Ecological
Contaminants Detected
- Log of sum of hazard quotients
Contaminants Not Detected
- Toxicity
- Persistence
Waste Quantity Multiplier
Receptors Score: Ecological
- Importance/sensitivity of biota/habitats in surface water
- Importance/sensitivity of "critical environments" within
1 mile of site
76
-------
TABLE B-4 (Continued)
Ground Water
Pathway Score
Contamination Detected
Contamination Not Detected
- Depth to ground water from base of waste or contaminated zone
- Permeability of unsaturated zone
- Infiltration potential
- Potential for discrete features to "short-circuit" pathway to
water table
Containment Multiplier
Contaminant Hazards Score: Human Health
Contaminants Detected
- Log of sum of hazard quotients
Contaminants not detected
- Toxicity
- Bioaccumulation
- Persistence
Waste Quantity Multiplier
Receptors Score: Human Health
- Estimated mean ground water travel time to nearest
downgradient well(s)
- Population served by affected aquifer(s) in downgradient
direction within 3 miles
- Ground water use of uppermost aquifer
- Population served by affected aquifer(s) in downgradient
direction within 3 miles
- Distance to nearest installation boundary
- Population within 1,000 feet of site
- Population served by affected aquifer(s) within 3 miles in
other than downgradient direction
- Estimated mean ground water travel time to nearest
downgradient surface water body that supplies water for
domestic use or for food-chain agriculture
- Population served by affected water body within 3 miles
downstream of discharge
Contaminant Hazards Score: Ecological
Contaminants Detected
- Log of sum of hazard quotients
Contaminants not detected (based on single contaminant)
- Toxicity
Waste Quantity Multiplier
77
-------
TABLE B-4 (Concluded)
Ground Water (Concluded)
Receptors Score: Ecological
- Estimated mean ground water travel time to downgradient
habitat or natural area
- Importance/sensitivity of downgradient habitats/natural areas
that are suspected discharge points
- Importance/sensitivity of "critical environments" within
1 mile of site
Source: Barathouse et al., 1986.
78
-------
DEPARTMENT OF THE AIR FORCE - HARM II (Continued)
SIMILARITIES
(Concluded)
TO MRS:
DIFFERENCES FROM HRS:
also multiply component scores to form
subscores and then calculate the site score
using root mean square algorithms.
There are several differences between HARM II
and the HRS. The most apparent is that HARM
II addresses only the ground water and
surface water pathways. A further
significant difference lies in the weighted
root mean square (wRMS) algorithm used by
HARM II in calculating the site score.
HARM II calculates a subscore for each
pathway-effects category combination. The
wRMS algorithm assigns the pathway-human-
health-effects subscores a weight of 5 while
it assigns the pathway-ecological-effects
subscores weight of 1. The HRS does not
treat the pathway-effects combinations
separately and effectively weights them
equally. A second significant difference
between the systems is the use of benchmarks
for health effects, ecological effects and
food chain accumulation in HARM II (the
hazard quotients). This is in contrast to
the use of the Sax toxicity index in the
HRS. Finally, HARM II utilizes a number of
factors not used in the HRS. The most
significant of these are travel time and
bioaccumulation potential. In part as a
result of these inclusions, HARM II relies
somewhat more on subjective judgment than
does the HRS.
Barnthouse et al. (1986) list the following
as the principal differences between the HRS
and HARM II: omission of the air pathway,
use of a standard four-point rating scale,
inclusion of factors appropriate to USAF
applications, assignment of difference
values to individual factors, incorporation
of additional site evaluation factors, and
the wRMS algorithm.
79
-------
DEPARTMENT OF THE AIR FORCE - HARM II (Concluded)
CONCLUSIONS: HARM II contains a number of features that
should be reviewed for possible inclusion in
the HRS. Of particular interest are the
hazard quotients used in assessing effects,
the travel time used in assessing the score
for receptors, the bioaccumulation factor,
and the use of the wRMS algorithm.
REFERENCES: Barnthouse, L. W. et al., Development and
Demonstration of a Hazard Assessment Rating
Methodology for Phase II of the Installation
Restoration Program, ORNL/TM-9857, Oak Ridge
National Laboratory, TN, 1986.
80
-------
DEPARTMENT OF THE INTERIOR
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
Impact Scoring Methodology
Office of Surface Mining, Department of the
Interior
Office of Surface Mining, Department of the
Interior
The Office of Surface Mining uses the impact
scoring methodology to assist in establishing
priorities for addressing problems associated
with abandoned mine land.
The methodology is used to assign relative
impact scores to the impacts resulting from
abandoned mine land (AML) problems. AML
problems include polluted water, subsidence,
water problems such as recurrent flooding
due to clogging of streams by mine sediments,
and mine facility hazards such as open
shafts, dangerous highwalls, and dangerous
abandoned equipment. Impacts from these
problems include injury and economic losses.
There are two factors used to calculate an
AML impact score. The first reflects the
amount of potential economic loss or injury
associated with the problem. The second
reflects the frequency with which the loss
or injury is likely to occur. The impact
score for a problem is calculated by summing
the value assigned to each factor. The
cumulative impact score for an AML problem
area is calculated as the weighted sum of
the individual impact scores for each
problem in the problem area.
The HRS and the impact scoring system are
not comparable (see Differences).
The HRS and the impact scoring system are
not comparable in that they are intended to
deal with entirely different types of
problems. The HRS is intended to rank the
relative threat of releases of hazardous
81
-------
DEPARTMENT OF THE INTERIOR (Concluded)
DIFFERENCES FROM HRS: substances. The impact scoring methodology
(Concluded) is intended to assign relative values to
impacts of problems such as open shafts,
abandoned equipment, and clogging of streams.
CONCLUSIONS: The impact scoring methodology is not
applicable to the ranking of hazardous
substance release sites.
REFERENCE: Tennessee Valley Authority and Oak Ridge
National Laboratory, A National Inventory of
Abandoned Mine Land Problems; An Emphasis
on Health, Safety, and General Welfare
Impacts, prepared for the Departments of
Interior and Energy, 1983.
82
-------
DEPARTMENT OF THE NAVY
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
Confirmation Study Ranking System (CSRS)
Department of the Navy, Navy Assessment and
Control of Installation Pollutants (NACIP)
Program
Adapted by the Navy from the Air Force HARM
system
Currently used in the NACIP to rank sites
prior to performing a complete sampling
program. Part of the DOD Installation
Restoration Program.
With three exceptions, CSRS is identical to
HARM. First, while HARM employs the average
of the receptors, pathways and waste
characteristics subscores in determining the
overall site score, CSRS uses the product of
these factors (this product is multiplied by
a waste management factor to give the overall
site score). The receptor and pathway rating
factors for both HARM and CSRS are listed in
Tables B-2 and B-3. Second, CSRS evaluates
containment slightly differently from HARM:
limited containment is assigned a value of
0.80 in CSRS rather than 0.95 as in HARM.
Finally, the two system evaluate waste
characteristics very differently. HARM
employs a matrix approach while CSRS
evaluates waste characteristics based on the
factors listed in Table B-5. Each factor is
evaluated on a scale of 0 to 3. This
evaluation is then multiplied by a factor-
specific multiplier to form a factor score.
The factor scores are then cross-multiplied,
as indicated, and the results summed. This
sum is then added to a physical state factor
score and normalized to a scale of 0 to 1,
to form the waste characteristics score.
The principal area of similarity between the
CSRS and the HRS is in the common factors
that both employ. For waste characteristics,
83
-------
TABLE B-5
ILLUSTRATION OF WASTE CHARACTERISTICS SCORING METHOD
Rating Factor
Waste Quantity (Q)
Acute Toxicity (AT)
Chronic Toxicity (CT)
Persistence (P)
Flammability (F)
Reactivity (R)
Incompatability (I)
Corrosiveness (C)
Solubility (S)
Bioaccumulation (B)
Physical State (PS)
Years site was in use (t)
Years since site was closed (t')
Scoring Factor
Factor
Rating (0 to 3)
Multiplier
AT x Q
CT x Q
C x Q
F x
R x
S x Q
P x Q x
B x (t
I x Q
Q
Q
t
+ t'
Subtotal
Physical State Weighted Factors
Total
Waste Characteristics Subscore 420/612 » 0.686
3
3
3
3
0
0
0
0
0
3
2
3
3
Score
72
72
0
0
0
0
162
108
0
414
6
420
1
8
8
6
4
4
5
3
5
6
3
1
1
Maximum Score
72
72
27
36
36
45
162
108
45
603
9
612
Factor
Score
3
24
24
18
0
0
0
0
0
18
6
3
3
84
-------
DEPARTMENT OF THE NAVY (Continued)
SIMILARITIES TO HRS:
(Concluded)
DIFFERENCES FROM HRS:
these common factors include physical state,
toxicity, waste quantity, persistence,
reactivity, and incompatibility. For site
characteristics (pathways) and receptors
(targets), the common factors are those
already identified in the HARM system. For
site characteristics, these include depth to
aquifer/ground water, net precipitation,
soil permeability and distance to nearest
surface water. For targets (or receptors),
these include ground water use, distance to
nearest well, land use, population served by
surface water or ground water, and critical
environments.
The CSRS and the HRS have a number of major
differences. First, their overall structures
are different. In the HRS, each pathway is
treated separately; in the CSRS the pathways
are combined in one scoring category
(pathways). Further, the CSRS does not
consider the air pathway. Also, containment
is treated as a single factor not a pathway
specific factor. Second, the scores are
combined in different fashions in the two
systems. In the CSRS, the subscores are
multiplied to form the site score while the
HRS site score is the root mean square of
the pathway scores. Third, the CSRS includes
a number of factors in the ranking that the
HRS does not, e.g., waste flammability,
corrosiveness, bioaccumulation potential,
years site was in use and years since site
was closed (time factors). Finally, in the
CSRS the waste characteristics score is a
complex combination of the waste
characteristics factors scores (e.g., the
toxicity score is multiplied by the quantity
score in the course of calculating the
overall waste characteristics score).
There are numerous additional differences
between the CSRS and the HRS, even in the
areas in which they are similar. In the
CSRS, acute toxicity and chronic toxicity
85
-------
DEPARTMENT OF THE NAVY (Concluded)
DIFFERENCES FROM HRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
are assessed separately using Sax and NFPA;
in the HRS one toxicity factor is employed.
For both ground and surface water, the HRS
considers just the population served by water
systems as a target category while the GSRS
considers both the population served and
total population (residential and working)
within 1,000 feet of the site. Other
examples of these subtle differences exist
between the systems.
The concepts embedded in the following GSRS
factors should be examined further (the
factors themselves are generally not
adequately defined for HRS purposes):
Potential for flooding
Surface soil permeability
Bioaccumulation potential
Time factors
Several other GSRS waste characteristics
factors not included in the HRS were
considered during the development of the HRS
(e.g., solubility) but were not included in
the HRS at that time because other factors
were judged to be more important or because
of problems with data availability and/or
factor definition (47 FR 10975, March 12,
1982). Those factors not included because of
the latter reasons should also be re-examined.
Luecker, Elizabeth B., "Navy Assessment and
Control of Installation Pollutant (NACIP)
Confirmation Study Ranking Model," Proceedings
of the Twelfth Annual Environmental Systems
Symposium, held on May 20-21, 1982 at Langley
Air Force Base, Langley, VA, American Defense
Preparedness Association, Arlington, VA, 1982.
Luecker, Elizabeth, NEESA, Port Hueneme,
California, personal communication to
Stuart Haus, The MITRE Corporation, April 11,
1985.
86
-------
B.3 State Waste Site Ranking Systems
This section contains summaries for systems developed or used
by eight states, primarily to supplement the use of the HRS in
determining State priorities in addressing sites. The systems
examined are as follows:
California
Connecticut
Illinois
Massachusetts
Michigan
New Hampshire
New Jersey
New York
87
-------
CALIFORNIA
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
CONCLUSION:
REFERENCES:
Public Health Benefit/Cost Ranking System
California Department of Health Services
California Department of Health Services
The system is used to develop the California
State Priority Ranking List which is a
ranking of sites for remedial action.
The system assigns a Public Health Index
(PHI) to a site based on the benefits and
costs of remedial action at the site. The
PHI is then used to rank sites for remedial
action. The PHI is calculated by dividing
the total benefits of remedial action by a
factor which is based on the estimated cost
of remedial action. The total benefits of
remedial action are calculated by summing
the HRS migration, fire and explosion, and
direct contact scores for the site.
Except for the remedial action cost factor,
the system is identical to the HRS.
The system differs from the HRS in that the
migration, fire and explosion, and direct
contact scores are summed and then divided
by the cost factor.
The Public Health Benefit/Cost Ranking
System is essentially identical to the HRS
and does not need to be considered any
further.
Dlugosz, Edward and Alan Ingham, "The
California Ranking System," Proceedings of
the National Conference on the 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. 429-431.
88
-------
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
CONNECTICUT
Untitled
Connecticut 208 Program, State of Connecticut
TRC Environmental Consultants, Inc.
Used by State of Connecticut to assign
priorities to sites for further
investigation.
The State of Connecticut evaluation system
is designed to classify sites into three
hazard categories: (1) those posing no
hazard and at which no further action is
required, (2) those at which a hazardous
condition may exist and at which further
investigation or monitoring is required, and
(3) those posing an imminent hazard that
requires action to assure health and safety.
The classification process is illustrated in
Figure B-2. A site is classified as posing
no hazard whenever it is not possible to
follow a continuous path through the diagram.
A site is classified as posing an imminent
hazard whenever any of the following seven
conditions pertain:
Improperly disposed liquid PCS wastes
Asbestos that can become airborne
Improperly disposed pesticides
Contaminants disposed within 200 feet of
a drinking water supply
Possible fire or explosion
Fish kills
Discharge of hazardous materials to storm
sewers or surface water
If the determination is made that a hazardous
condition may exist and further investigation
is required, then additional information is
collected, evaluated, and a sampling program
is initiated as needed. In the case of
potential air contamination, a sampling
program is initiated without further
investigation. In the case of suspected
89
-------
DISPOSAL
SITE
Historical
Dump
Site
i
Surface
Impound-
ment
!
Drum
Container
or Tank
Storage
i
Landfill
<
Sites
Showing
Application
of Liquids
Other
Contam-
inated
Sites
!
POLUTANT
THREATENED
OR ACTUAL
CONDITIONS
LOCATION
Discharge to
Storm Sewers,
Drains or
Surface Water
In Regulatory
Floodway,
100 Year Flood Plain,
Coastal Rood
Hazard Areas
In Primary
Recharge Zone
of a Drinking
Water Aquifer
Within 200 Feet of
a Well or Drinking
Water Supply
Potential Health Hazard
Warranting Funhur Investigation
FIGURE B-2
OVERVIEW OF CONNECTICUT SCORING SYSTEM
-------
CONNECTICUT (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
surface water contamination, information is
obtained on the distance to the nearest
waterbody and the direction of runoff before
a sampling program is designed. In the case
of suspected ground water contamination, an
adaptation of the original LeGrand system
(see Section B.4) is employed to classify
the degree of hazard posed by the site and
to determine the appropriate course of
action. Information is collected for
several characteristics of the site and used
to develop factor scores for the following
six factors using the line graphs in Figures
B-3 (for sites underlain by loose granular
material) and B-4 (for sites underlain by
less than 20 feet of till or soil above the
bedrock):
Depth to water table (0 to 10 points)
Sorption (0 to 6 points)
Permeability (0 to 6 points)
Gradient (0 to 7 points)
Distance to nearby wells (0 to 7 points)
Thickness of porous materials below
disposal point (0 to 6 points)
The scores for each factor are summed to
form a site score and the degree of hazard
is determined as follows:
0 to 8: Imminent hazard
8 to 15: Probable or possible hazard
Above 15: Not an imminent hazard
There are few similarities between the
Connecticut system and the HRS. The only
important similarities are that both use the
following factors, although in different
fashions: depth to water table, permeability
and distance to nearest well.
The Connecticut rating system applies only
to the ground water pathway. Except for a
distance to nearby wells factor, the system
corresponds only to the HRS ground water
route characteristics category. The
91
-------
WT
012345 6 78 9
Ii i i i I i i ii i
ii i 1 1 i ~" 1 i i
5 10 20 30 40 50 75 100 200
Distance Below Base of Disposal Unit - Feet
01 2 3 4 4.5 5
1 i i i i i i
Coarse Coarse Clean Small Amounts Silt Equal Amounts
Gravel Sand Of Clay In Sand Of Clay And Sand
6543 2 1
i i i i
Clay Silt or Clayey Fine Sand Fractured Rock Coarse Sand
Sandy Clay Sand
* ^ rn
i -AD - i 1 U
0 1 23456
i i i i i i i
1 iii ii
60 30 20 10 0 10
Percentage
0 123456
»l ii iii
iii 1 i 'iii i
25 50 100 200 300 500 1,000 2,500 1
I ... Tool ... .1 1 M
10
1
1,000
6
1
Clay
0
j
Clean Gravel
1
7
i
1
60
7
1
10
Hoc 1
The Scales for the various factors are labeled as follows: WT, Water Table; S, Sorbtion; P, Permeability; G, Gradient; D, Distance. On all scales the
point values are indicated by the upper scale; the brackets indicate unacceptable ranges for any factor, except the two brackets on the gradient
scale, one labeled "AD", which is for an adverse direction of flow (toward point of water use), and one "FD" Which is for a favorable direction of flow.
Source: State of Connecticut 208 Program, 1980.
FIGURE B-3
RATING CHART FOR SITES IN LOOSE GRANULAR MATERIALS
-------
rr
s
p
G
D
T
01234 5
i i i i i 1 i
1 '11' i 1 1
5 10 20 30 40
0 1
1
Fractured Coarse Clean
Rock Sand
654 3
Ii i i
1
Clay Silt or Clayey
Sandy Clay Sand
An
0
i i
60 30 20
0
i i
25 50 100
1
012 3
1 ^1 . L-^ 1-^ f
678 9 10
III 1 1
1 1 1 1 |
50 75 100 200 1,000
Distance Below Base of Disposal Unit - Feet
2 34
1 ' 1
Small Amounts Equal Amounts Clay
Of Clay In Sand Of Clay And Sand
2 1 0
Fine Sand Fractured Rock Coarse Sand Clean Gravel
F~D
123456 7
10 0 10 60
Percentage
1 23456 7
1 i i i i i i
1 i iii i |
200 300 500 1,000 2,500 1 10
Font ' I Milnr I
45 6
. L, J , 1 . , _ i
0 10 20 30 40 50 60 70 80 90 100
Feet
200
300
The Scales for the various factors are labeled as follows: WT, Water Table; S, Sorbtion; P, Permeability; G, Gradient; D, Distance, and T, Thickness
of porous granular materials below disposal point. On all scales the point values are indicated by the upper scale; the brackets indicate unacceptable
ranges for any factor, except the two brackets on the gradient scale, one labeled "AD", which is for an adverse direction of flow (toward point of water
use), and one "FD" Which is for a favorable direction of flow.
Source: State of Connecticut 208 Program, 1980.
FIGURE B-4
RATING CHART FOR TWO-MEDIA SITES
-------
CONNECTICUT (Concluded)
DIFFERENCES FROM HRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
The Connecticut system contains three factors
that do not correspond to any factors
included in the HRS ground water route
characteristics cateogry: sorption,
gradient, and thickness of porous materials.
The Connecticut system and the HRS are
designed to achieve broadly similar purposes:
the identification of sites that potentially
pose a significant risk. Otherwise, they
are not comparable, except to the extent
that the original LeGrand system shares
three factors in common with the HRS. The
concepts embedded in the three other factors
included in the Connecticut system, but not
in the current HRS, should be investigated
(see also the LeGrand system). The factors
themselves are not adequately defined for
use in the HRS.
Unites, Dennis, Mark Possidento and John
Housman, "Preliminary Risk Evaluation for
Suspected Hazardous Waste Disposal Sites in
Connecticut," 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. 25-29.
LeGrand, Harry E., "System for Evaluation of
Contamination Potential of Some Waste
Disposal Sites," JAWWA, 1964, pp. 959-974.
State of Connecticut 208 Program, Hazardous
Waste Site Evaluation Manual, (1076-J80-80),
prepared by TRC, Environmental Consultants,
Wethersfield, CT, 1980.
94
-------
ILLINOIS
SYSTEM:
USER:
Developer:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
Rating scheme
State of Illinois, Department of Energy and
Natural Resources
State of Illinois, Department of Energy and
Natural Resources
Used by the State of Illinois as a screening
tool, for regional planning, to identify and
assign priorities to sites or areas for more
detailed study and evaluation.
The rating scheme is intended as a screening
tool for regional planning. It is used to
rank the relative threat to human health
posed by sites via the ground water pathway.
The rating scheme is composed of four
factors: health risk of waste and handling
mode, population at risk, proximity of waste
activity to public water supply wells or
potable aquifer, and aquifer susceptibility.
The elements contained in these factors are
listed in Table B-6. Each element is
assigned a numerical value (on a scale
ranging between 0 and 10, 50, 80, or 100)
according to prescribed guidelines. These
guidelines are different for active and
abandoned sites. Total scores for the first
three factor range from 0 to 100, while the
score for the fourth factor ranges from 0
to 50. The four factor scores are added and
divided by 3.5 to give an overall score
between 0 and 100.
The rating scheme is intended to evaluate
ground water threats. As such, it
corresponds to the HRS ground water pathway.
The rating scheme and the HRS ground water
pathway contain three elements that are
similar in concept, but which are defined
and evaluated differently. These are:
waste quantity, waste hazard, population at
risk, and aquifer susceptibility.
95
-------
TABLE B-6
FACTORS AND ELEMENTS IN THE ILLINOIS RATING SCHEME
Factors
Health risk of waste and
handling mode
Population at risk
Proximity of waste activity
to public water supply
Aquifer susceptibility
Elements
Waste quantity
Recorded management of waste
Potential hazard of waste
Population at risk if within public
water supply well capture zones
Population at risk for sites outside
public water supply well capture
zones
Age of hazardous waste activity if
within public water supply well
capture zones
Density of hazardous waste activity
for sites outside public water
supply well capture zones
Aquifer susceptibility to surface
sources of pollution
Source: Gibb et al., 1983.
96
-------
ILLINOIS (Concluded)
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES:
The rating system contains two elements that
do not correspond to any factors present in
the HRS ground water pathway: recorded
management of hazardous waste (e.g., whether
the site was well operated, whether it
received municipal or industrial wastes) and
the age or density of hazardous waste activity
relative to the proximity of the activity to
public water supplies. As noted above, four
other factors in the rating scheme are
evaluated differently than in the HRS. Waste
hazard applies only to RCRA listed wastes and
is evaluated using the ranking scheme from
the RCRA Risk-Cost Analysis Model. Population
at risk is evaluated by determining whether a
site falls within a 75-year capture zone of a
public water supply well. If so, it is scored
based on the population using the well; if
not, it is scored based on population density.
Waste quantity is based upon a different scale
than in the HRS and is evaluated differently
for abandoned sites and active sites. Waste
susceptibility is evaluated based on the
thickness and permeability of the material
overlaying an aquifer.
The population at risk element in the rating
scheme needs to be further evaluated with
regard to its applicability to the HRS. The
other factors are either not appropriate for
inclusion in the HRS (e.g., recorded
management of waste) or are not adequately
defined in their present form for inclusion
in the HRS (e.g., aquifer susceptibility).
Gibb, J., M. Barcelona, S. Schock, and
M. Hampton, Hazardous Waste in Ogle and
Winnebago Counties; Potential Risk via
Groundwater Due to Past and Present
Activities, Illinois Department of Energy and
Natural Resources, Document No. 83/26,
Springfield, IL, 1983.
97
-------
MASSACHUSETTS
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
Prioritization of Environmental Risks and
Control Options (PERCO)
Developed for the Massachusetts Department
of Environmental Quality Engineering (DEQE)
Arthur D. Little, Inc.
The development of PERCO has been completed
by Arthur D. Little. It is now being
studied by DEQE. No schedule is available
for possible implementation of PERCO by DEQE.
PERCO was designed by ADL with the objective
of enabling DEQE to rank sites in terms of
immediate and long-term environmental and
human health hazards and to provide a
rationale for allocation of remedial action
funds. The model was designed to reflect
the risks of the sites and the risk/benefit
trade-offs that might result from remedial
actions. The model addresses both chronic
and episodic (acute) hazards. Four pathways
are used for chronic hazards: air, ground
water, surface water, and soil/direct
contact. Three types of episodic hazards
are considered: fire and explosion, toxic
vapor, and floods. The overall PERCO
structure is illustrated in Figure B-5.
With regard to the four chronic pathways, a
human health score is calculated for each
pathway, as described below, and the four
human health scores are summed to determine
the total health score for the site. In
addition, for the surface water pathway,
three optional scores (i.e., recreation,
fishing, and ecological) may be calculated.
For the soil/direct contact pathway, an
optional land score may be calculated.
These optional scores are not used in
determining the total site score; rather
they just provide additional information for
subjective use by DEQE.
98
-------
Health Hazard Score
Ecological Hazard Score
Health Hazard Score
Property Hazard Score
Control Option
Costs
c
Priorties for
Control Options
Source: Arthur D. Little, Inc., 1982.
FIGURE B-5
OVERVIEW OF PERCO SYSTEM
99
-------
MASSACHUSETTS (Continued)
GENERAL DESCRIPTION: For the ground water and surface water
(Continued) pathways, the human health score is
determined through the use of concentration
data and human health effects benchmarks.
The concentration of each hazardous
constituent (based on one or more samples)
is divided by a subjectively chosen, chronic
human health benchmark for that constituent.
This gives a severity ratio for each
constituent. The severity ratio for each
constituent is then summed to give the total
severity ratio. This total severity ratio
is then multiplied by the population served
by the water body to give the human health
score. The distance from the site over
which the surface water or ground water
population is counted is subjectively
determined by the person rating the site.
If concentration data (i.e., at least one
sample) are not available for a site, then
similar sites to the site being scored are
identified subjectively or in the case of
the surface water pathway through the use of
optional guidelines. The concentration data
from these similar sites are then used in
the above procedure to determine a human
health score for the site being rated.
Two of the three optional surface water
scores (recreation and fishing) are
calculated in a similar manner. The total
contaminant severity ratio is multiplied by
either the annual person-hours of recreation
for the water body (recreation score) or the
pounds of fish caught and eaten from the
water body multiplied by a bioconcentration
factor (fishing score). The ecological
score is the maximum ratio of the
contaminant concentrations divided by a
subjectively chosen ecological toxicity
benchmark.
For the soil/direct contact pathway, the
human health score is determined by dividing
100
-------
MASSACHUSETTS (Continued)
GENERAL DESCRIPTION: the acres of crops grown in contaminated
(Continued) soil off the site by a subjectively chosen
crop concentration factor (CCF). (The CCF
is meant to relate the contamination of
irrigated crops by water to resulting human
health risks and damages. No guidance is
provided for determining the CCF. The HRS
factor of 1.5 persons per irrigated acre is
recommended as a default value.) The above
ratio is summed for each crop, and the sum
is the soil/direct contact human health
score.
The optional land score for the soil/direct
contact pathway is calculated by first
determining the annual person-hours of
people present on the contaminated soil.
This is the usage rate. The usage rate is
divided by a subjectively chosen acute human
health toxicity benchmark. This ratio is
the land score. The land score is summed
for all contaminated soil to give the total
land score.
For the air pathway, the human health score
is obtained by first determining a set of
concentric concentration rings around the
site. The population within each ring is
determined and multiplied by a weight for
that ring. The weighted population for each
ring is then summed to give the human health
score for the air pathway. The radius of
each ring is determined through a complex
procedure involving the use of simplified
air dispersion equations and subjectively
chosen human health effects benchmarks. One
or more air samples from downwind of the
site is required for the calculation. If
such monitoring data are not available, then
similar sites to the site being rated are
identified either subjectively or through
the use of optional guidelines. The
concentration data from these similar sites
are then used in the above procedure.
101
-------
MASSACHUSETTS (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
In addition to the four chronic pathway
scores, three episodic (acute) hazard scores
are determined. These episodic scores are
not used in calculating the total site
score; rather they provide additional
information for subjective use by DEQE. Two
of the episodic scores (toxic vapors and
fire and explosion) are determined in a
manner that is generally similar in concept
to the air pathway health score. The
flooding score is calculated as the product
of a flooding potential factor, a waste
quantity factor, and a toxicity/persistence
factor.
The principal similarity between the HRS and
PERCO is that both address the ground water,
surface water, air, direct contact, and fire
and explosion pathways. The methods used in
each for addressing these pathways are very
different, however. The only similarity is
that both consider the population-at-risk.
PERCO and the HRS are very different systems.
PERCO requires that concentration data be
used in rating a site. Just one sample is
considered sufficient for rating a site. If
data are not available, PERCO attempts to
identify similar sites to the site being
ranked and uses data from those similar
sites in ranking the site. Thus PERCO
implicitly assumes that a fairly
comprehensive set of ambient measurements
for hazardous waste sites exists. The HRS,
in contrast, uses concentration data
primarily to determine if an observed
release has occurred. If there is no
observed release, the HRS uses surrogate
(potential for release) measures. Another
critical difference between the two systems
is that many of the factors used in PERCO
are subjectively determined by the person
rating the site. These include the health
effects benchmarks and the surface water and
ground water target distance limits. In the
102
-------
MASSACHUSETTS (Concluded)
DIFFERENCES FROM MRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
HRS most factors are specified in advance to
ensure consistent and uniform rating of
sites. Another difference is that PERCO
addresses options for remedial action and
subjectively assesses their risk/benefit
trade-offs. This is not done in the HRS.
Four concepts used in PERCO warrant further
evaluation. One is the use of health
effects benchmarks as part of any
concentration based factor. The second is
the use of data from similar sites rather
than using potential for release factors in
rating a site. The third is the use of air
dispersion equations to specify distance
rings for rating the target population in
the air pathway. (The HRS currently uses
distance rings, but they are specified in
advance and do not vary from site to site.)
The last is the use of flooding factor.
None of the four concepts are defined well
enough in PERCO for direct use in the HRS.
Arthur D. Little, Inc., PERCO; A Model for
Prioritization of Environmental Risks and
Control Options at Hazardous Waste Sites,
Arthur D. Little, Inc., Cambridge, MA,
September 12, 1983.
Bois, Robert, Massachusetts Department of
Environmental Quality Engineering, personal
communication to Carol Burger, The MITRE
Corporation, September 18, 1986.
103
-------
MICHIGAN
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
Site Assessment System (SAS)
State of Michigan, Department of Natural
Resources
State of Michigan: Department of Natural
Resources, Department of Agriculture,
Legislative Bureau, Department of Health,
and Toxic Substance Control Commission
Currently used by the State of Michigan to
assess and prioritize sites, in terms of
relative risk, for further investigation and
remedial action.
GENERAL DESCRIPTION:
SAS is a multi-pathway ranking system
designed to reflect the relative risk posed
by sites to public health and environmental
resources. The system is illustrated in
Tables B-7 and B-8. Five exposure pathways
are reflected in SAS: ground water, surface
water, air, direct contact, and fire and
explosion. Each pathway is evaluated
independently, and a site subscore calculated
as the square root of the sum of the squares
of the pathway scores. This score is then
added to a chemical hazard score to form the
overall site score.
Each pathway score is the sum of a potential
exposure score and an existing exposure
score. In turn, the potential exposure
score is the product of a release potential
score multiplied by the sum of environmental
exposure, and targets scores. This
calculation procedure is illustrated in
Table B-7. The factors addressed in
evaluating these scores are listed in
Table B-8.
The chemical hazard score is evaluated,
independent of pathway, using the complex
approach illustrated in Figure B-6. This
approach considers diverse factors including
104
-------
TABLE B-7
MICHIGAN SITE ASSESSMENT SYSTEM SCORE
SHEET
^^^^^N^^^ Route
Category ^"""^^^
Potential Exposure
Release
Potential (RP)
Environmerrtai
Exposure (EnE)
Targets (T)
Potential Exposure (PE)
Score - (EnE+T) x RP
1 1
"5 5
Existing
Exposure (E&E)
Route Score
PE + E&E
Ground Water
Rating
Factor
Release
Potential
Un-
saturated
Zone
Population
At Risk
Saturated
Zone
Existing
Exposure
Range of
Scores
0-2
0-100
0-100
0-60
0-520
0-250
0-770
Site
Score
Surface water
Rating
Factor
Release
Potential
Distance
To Surface
Water
Site
Slope
Flood
Potential
Population
At Risk
Drinking
Water
Population
Wetlands
Cold
Water
Fish
Warm
Water
Fish
Existing
Exposure
Range of
Scores
0-2
0-40
0-40
0-20
0-100
0-40
0-10
0-15
0-10
0-530
0-250
0-780
Site
Score
Air
Rating
Factor
Release
Potential
Mobility
Site
Activity
Population
Existing
Exposure
Range of
Scores
0-2
0-70
0-30
0-100
0-400
0-250
0-650
Subscore(SS) PW2 + SW2 + Air2 + DC2 + FE2] [[770]2 + [780]2 + [650]2 + [400]2 + [420]2 ] 1/2
Chemical
Hazard
Chemical
Hazard (CH)
Site
Score
Direct Contact
Rating
Factor
Release
Potential
Access-
ibility
Atract-
Iveness
Population
0-1 ,400
I Site Score CH + SS
0-2.000
Range of
Scores
0-2
0-60
0-20
0-100
0-400
0-400
Site
Score
Fire and Explosion
Rating
Factor
Release
Potential
Ignition
Source
Waste
Separation
Population
Wetlands
Range of
Scores
0-2
0-50
0-50
0-100
0-10
0-420
0-420
Site
Score
-------
TABLE B-8
SITE ASSESSMENT SYSTEM RATING FACTORS
^^Route
Category^s^
Release
Potential
Environmental
Exposure
ut
CD
&
i2
Population
at Risk
Resource
Value
Existing
Exposure
Ground Water
Physical state
Containment effectiveness
Unsaturated zone
Population within target
area
Population served by well
field within 1/2 mile of site
Saturated zone
Exposure over background
levels
Population exposed
Surface Water
Physical state
Containment effectiveness
Site slope
Flood potential
Distance to surface water
1/2 the population within
the target area
Drinking water supply
population
Fisheries designation
Wetlands
Drinking water
Exposure over background
levels
Population exposed
Fish advisory
Air
Physical state
Containment effectiveness
Mobility
Site activity
Population within target
area
Non-applicable
Exposure over background
levels
Population exposed
Odors
Direct Contact
Physical state
Containment effectiveness
Accessibility
Attractiveness
1/2 the population within
the target area
Non-applicable
Non-applicable
Fire and Explosion
Physical state
Containment effectiveness
Ignition source
Waste segregation
Population within target
area
Wetlands
Non-applicable
Chemical
Hazard
Mammalian toxicity
Aquatic toxicity
Bioaccumulation
Persistance
Flam inability
Reactivity
Chemical quantity
Source: Iversonetal., 1983.
-------
Acute Taoxicity
+
Genotoxitity
+
Subchronic/ Chronic
Toxicity
+
Ecological
Toxicity
+
Bioaccumulalion
+
Persistance
Quantity
of
Identified
Chemicals
Flam ability
and/or
Reactivity
Quantity
of
Unidentified
Materials
Weighted Average
Source: Iverson et al., 1983.
FIGURE B-6
SITE ASSESSMENT SYSTEM CHEMICAL HAZARD SCORING PROCESS
-------
MICHIGAN (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
toxicity (acute, subchronic, chronic,
ecological, and genotoxicity),
bioaccumulation potential, persistence,
flammability, reactivity, and data
uncertainty.
There are several similarities between the
HRS and the SAS, as seen in Tables B-7
and B-8. Each employs the same five
pathways. Each addresses potential and
observed release, similar targets and waste
characteristics. Additionally, many of the
same factors are employed in evaluating the
categories. Both systems employ the root-
mean-square of the weighted sum of the
pathway scores to form the site score (or
subscore).
There are several significant differences
between the two systems (see Tables B-7
and B-8). First, SAS addresses potential
and existing exposure separately, and adds
the scores for both to form the route
score.
Second, the waste characteristics/chemical
hazards portions of the two systems, while
serving similar purposes, are evaluated very
differently. In the HRS, the degree of
hazard posed by the wastes is evaluated for
each pathway in terms of the Sax toxicity
score together with other factors such as
quantity and persistence. In contrast, SAS
employs the approach discussed above. Also,
chemical hazard in SAS is treated
independently of pathway (in contrast to the
HRS approach).
Third, the two systems are combinatorially
very different. For example, in the SAS
ground water pathway, a score for
permeability and depth to the aquifer of
concern (unsaturated zone factor score) are
added to the targets score, the sum then
multiplied by the release potential score to
form the potential exposure score. In the
108
-------
MICHIGAN (Continued)
DIFFERENCES FROM HRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
HRS, permeability, depth to aquifer and other
factor values are summed and then multiplied
by a targets value to form a similar score.
Further, the pathway score is the sum of the
exposure subscore and the chemical hazard
score in SAS, while in the HRS, the waste
characteristics score (which includes
toxicity related factors) is multiplied by
the release category and targets values to
form the overall score. Also, all five
pathways are included in SAS in evaluating
the site score. In contrast, the direct
contact and fire and explosion pathways are
not included in the HRS site migration score.
Finally, in many cases, the procedures used
to evaluate the common factors are different
in the two systems. For example, in the SAS
ground water pathway, permeability and
thickness of the unsaturated zone are
evaluated in a matrix, while in the HRS,
they are evaluated independently and their
factor values added.
SAS is a complex ranking system, sharing
some characteristics with the HRS, while
also differing strongly from the HRS in
other respects. It considers many of the
same factors as the HRS although the scoring
methods are usually different. The complex
method used to evaluate chemical hazard
should be evaluated in detail for possible
adaptation for use in the HRS.
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.
Michigan Department of Natural Resources,
1984 Review Report Michigan Site Assessment
System, Michigan Department of Natural
Resources, September 1984.
109
-------
MICHIGAN (Concluded)
REFERENCES: Michigan Department of Natural Resources,
(Concluded) Appendix C; Guidance to SAS Model
Application, Michigan Department of Natural
Resources, July 1985.
Roycroft, Dianne, Michigan Department of
Natural Resources, Groundwater Quality
Division, personal communication to Thomas F.
Wolfinger, The MITRE Corporation, August
1985.
110
-------
NEW HAMPSHIRE
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
Untitled
New Hampshire Department of Health and
Welfare
New Hampshire Department of Health and
Welfare
Used by New Hampshire to rank sites for
further assessment and remedial action.
New Hampshire uses its system to rank
hazardous waste disposal sites in three
categories; high, medium and low priority.
The indicator of hazard is potential for
carcinogenic effects. By default, all NPL
sites are assigned a high priority. Thus,
the focus of the system is on non-NPL
sites. The system is simple; site scores
are the sum of a carcinogenic potential
score and an exposure potential as shown.
Carcinogenic potential is scored as follows:
Human postive: 3
Animal positive: 2
Nonsuspect: 1
Presumably, the score is based on the maximum
carcinogenic potential of all the substances
at the site.
Exposure potential is scored as follows:
Direct exposure:
Potential exposure:
Unlikely exposure:
3
2
1
The only important similarity between the
two systems is that the New Hampshire system
assigns a high priority to NPL sites and
hence to sites with an HRS score exceeding
28.50.
Ill
-------
NEW HAMPSHIRE (Concluded)
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES:
The only important difference between the
two systems is the method used by New
Hampshire to score carcinogenic potential.
The method for scoring carcinogenic potential
should be examined when the HRS methods for
scoring toxicity are examined.
Dupee, Brook S., Environmental Health Risk
Assessment Unit, Memorandum to Brian C.
Strohm, Assistant Director, Division of
Public Health Services, New Hampshire
Department of Health and Welfare, May 18,
1984.
Dupee, Brook S., Environmental Risk
Assessment Unit, New Hampshire Department of
Health and Welfare, personal communication
to Stephen Lubore, The MITRE Corporation,
March 8, 1985.
Dupee, Brook S., Environmental Risk
Assessment Unit, New Hampshire Department of
Health and Welfare, personal communication
to Thomas F. Wolfinger, The MITRE
Corporation, September 13, 1985.
112
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SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
NEW JERSEY
Severity Index
State of New Jersey, Department of
Environmental Protection (DEP), Division of
Hazardous Waste Management
Unknown
Used by New Jersey DEP to prioritize sites
for site inspection.
The Severity Index is used by the New Jersey
DEP to prioritize sites for site inspections
(SI) based on the data obtained during a
preliminary assessment (PA). The Severity
Index calculates a total site score as the
product of a waste characteristics score and
an exposure potential score, divided by 100
to normalize the final score.
In determining the waste characteristics
score, the system employs the HRS toxicity/
persistence, waste quantity, and containment
factors and associated evaluation tables.
The waste characteristics score is calculated
as the sum of the toxicity/persistence score
and the waste quantity score all multiplied
by the containment score.
The exposure potential score is the product
of a population density/sensitive environment
score multiplied by the sum of six exposure
medium scores. The six exposure media are:
Ground water
Surface water
Air
Soil
Fire/explosion
Direct contact
The population density/sensitive environment
scoring approach is unique to the Severity
113
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NEW JERSEY (Concluded)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
CONCLUSION:
REFERENCES:
Index. The six exposure medium scores are
each calculated as the product of a basic
score and an observed score. If contamin-
ation is observed in the medium under con-
sideration, then the observed score is set
equal to 2; otherwise it is set equal to 1.
The basic scores for the ground water and
surface water medium are similar to the HRS
ground water and surface water use factors.
The remaining four basic scores are based on
assessments of the potential for contamin-
ation of air or soil, for direct contact of
hazardous substances by humans, or for fire
and explosion. If such a potential is deemed
to exist for any of the four exposure media,
a basic score of three is assigned to that
exposure medium; otherwise, a basic score of
zero is assigned to that exposure medium.
Most of the factors in the Severity Index
are identical to, or very similar to, HRS
factors. These factors and their evaluation
methods are the only similarities between
the two systems.
The major difference between the two systems
lie in the four exposure medium scores used
in the Severity Index, the algorithms used
to calculate the overall site scores (as
discussed above), and the many factors
included in the HRS that are not reflected
in the Severity Index (e.g., the ground
water route characteristics factors). The
four exposure medium scores are apparently
assessed subjectively. If a potential for
exposure exists in the opinion of the
analyst, a maximum score of 3 is assigned.
If not, a score of 0 is assigned.
The Severity Index is derived from the HRS.
No further analysis is warranted.
Kenneth J. Kloo, New Jersey Department of
Environmental Protection, letter and
attachments to Wayne Praskins, U.S.
Environmental Protection Agency, Washington,
DC, July 30, 1986.
114
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NEW YORK
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
Human Exposure Potential Ranking Model
(HEPRM)
State of New York, Department of Health,
Bureau of Toxic Substance Assessment
Life Systems, Inc.
Under development for the New York State
Department of Health to prioritize sites for
further investigative and remedial actions.
HEPRM is designed to rank sites based on
their potential for impacting human health.
Scores are first developed within the system
for 40 potential human exposure pathways
(e.g., ingestion of surface water). The
human exposure pathways are grouped into
four media (i.e., air, soil, ground water,
surface water). A score is determined for
each medium by summing the appropriate
pathway scores. The overall site score is
determined by summing the scores for each
medium. Table B-9 lists the human exposure
pathways within each medium.
Each human exposure pathway score is
calculated as the product of four factors: a
chemical factor, a target factor, a
probability of release factor, and a
weighting factor. Each of these factors is
determined based on other factors, as
discussed below. These other factors vary
according to the exposure pathway being
scored.
There are seven chemical factor scores, only
one of which is used per exposure pathway.
Each of the seven chemical factor scores is
calculated as the product of a toxicity
score and a migration potential score.
Three route-specific toxicity scores (i.e.,
ingestion, inhalation, and dermal) and a
general toxicity score are determined for
contaminants based on the Sax rating scheme
used in the HRS. Four categories of
115
-------
TABLE B-9
HEPRM EXPOSURE PATHWAYS
Air
Soil
Inhalation of air vapor (on-site)
Inhalation of air vapor (off-site)
Inhalation of particulates (on-site)
Inhalation of particulates (off-site)
Inhalation of soil vapor (basement)
Ingestion of soil (on-site)
Dermal contact with soil (on-site)
Ingestion of plants (on-site)
Ingestion of airborne soil (off-site)
Dermal contact with airborne soil (off-site)
Ingestion of plants (airborne) (off-site)
Ingestion of waterborne soil (off-site)
Dermal contact with waterborne soil (off-site)
Ingestion of plants (waterborne) (off-site)
Ground Water
General:
Ingestion of ground water (water supply)
Inhalation of ground water (water supply)
Dermal contact with ground water (water supply)
Inhalation of ground water vapor (basement)
Dermal contact with ground water (basement)
Dermal contact with seepage
Ingestion of plants (irrigation)
Surface Water Recharged by Contaminated Ground Water;
Ingestion of surface water (water supply)
Dermal contact with surface water (water supply)
Inhalation of vapors from surface water (water supply)
Ingestion of surface water (recreation)
Dermal contact with surface water (recreation)
Ingestion of plants (irrigation)
Ingestion of aquatic biota
116
-------
TABLE B-9 (Concluded)
Surface Water
General:
Ingestion of surface water (water supply)
Dermal contact with surface water (water supply)
Ingestlon of surface water (recreation)
Dermal contact with surface water (recreation)
Ingestion of aquatic biota
Ingestion of plants (irrigation)
Surface Water Receiving Runoff from Lagoon Overflow;
Ingestion of surface water (water supply)
Dermal contact with surface water (water supply)
Inhalation of vapors from surface water (water supply)
Ingestion of surface water (recreation)
Dermal contact with surface water (recreation)
117
-------
NEW YORK (Continued)
GENERAL DESCRIPTION: migration scores (i.e., soil contact, soil
(Continued) vapor, ground water vapor, and ground water
contact) are calculated and are generally
based on vapor pressure and water solubility
characteristics of the contaminants. The
three toxicity routes and the four migration
categories are used to define the seven
chemical factor scores (e.g., chemical factor
score for soil contact-ingestion). The score
for each chemical factor is based on the one
contaminant with the highest score for that
chemical factor.
There are seven probability scores, only one
of which is used per exposure pathway. The
seven probability scores are each calculated
differently; however, each provides for
assessing the probability based on either
documented evidence of release or potential
for release (or potential for contact, as
applicable), as does the HRS. Table B-10 lists
the factors evaluated in each "potential"
probability calculation. Many of the factors
are identical or nearly identical to factors
in the HRS, as indicated in the table.
There are 18 target scores, only one of which
is used per exposure pathway. The 18 target
scores share a common, basic methodology.
In each, the population potentially affected
is estimated in up to four distance classes.
The classes are based on concentric rings at
specified distances from the site. For
example, the four classes used to estimate the
ground water supply target score are (1) less
than 160 meters, (2) 160 to 1,000 meters,
(3) 1,001 to 4,000 meters, and (4) greater
than 4,000 meters. The potentially affected
population is calculated for each class and
evaluated using a population scoring table.
The final target score is the normalized sum
of the products of the population scores for
each distance class and a distance class
score. Several of the target scoring
118
-------
TABLE B-10
HEPRM PROBABILITY FACTORS
Category
Factors
On-Site Contact
Ground Water Transport
Air Vapor Transport
Air Particulate Transport
Surface Water Transport
Soil Vapor Transport
On-Site Plant Ingestion
Accessibility
Containment
Adjacent Population
Aquifer Proximity*
Net Precipitation*
Permeability*
Containment*
Leaching Potential**
Containment
Reactivity/Incompatability*
Evaporation Potential***
Precipitation (Percent Dry Days)
Containment
Site Area
Disturbance
Containment*
Rainfall*
Site Area
Disturbance
Site Slope/Terrain*
Permeability*
Evaporation Potential***
Containment*
Landfill Type
Depth to Waste
Not available
*Factor identical or nearly identical to HRS factor.
**Based on vapor pressure and water solubility of contaminants of
concern.
***Based on vapor pressure of contaminants of concern.
119
-------
NEW YORK (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
procedures employ variations on this
approach to reflect specific additional
considerations. For example, the on-site
contact target scores employ only one class
since the targets are all on-site.
In addition to the chemical, probability and
target scores, HEPRM employs 40 weighting
factors reflecting the relative importance
of each human exposure pathway in
determining overall human health risk.
These weighting factors were developed based
on the product of an exposure coefficient
and the estimated maximum daily intake of
contaminant resulting from a concentration
of 1 ppm of contaminant in the appropriate
media. The exposure coefficient for each
pathway was based on a "reasonable worst
case" estimate of exposure frequency,
duration, and magnitude as well as other
relevant factors.
As stated above, the 40 exposure pathway
scores are calculated as the product of the
appropriate chemical factor scores,
probability scores, target scores, and
weights.
There are two important areas of similarity
between HEPRM and the HRS. Both address
common routes for human exposure and
associated potential human health impact,
for example ingestion of contaminated ground
water. Also, as indicated above, the two
systems share many common factors and
several HEPRM factors are based on HRS
factors (e.g., containment and net
precipitation in assessing the probability
of ground water transport).
Despite the similarities between HEPRM and
the HRS, there are a large number of
differences between the two systems. The
more important differences are differences
in basic philosophy, differences in the
exposure pathways, differences in the
120
-------
NEW YORK (Continued)
DIFFERENCES FROM HRS: calculation procedures, and differences in
(Continued) the applicability of the systems. There are
also minor differences in the approaches
used to calculate common factors (e.g., for
many factors, the minimum score in HEPRM is
0.1 rather than 0 as is used in the HRS).
As discussed above, HEPRM is an exposure
pathway system while the HRS is a contaminant
migration pathway system. Thus, HEPRM
delineates a large number of exposure
pathways explicitly, while the HRS delineates
three basic contaminant migration pathways
explicitly and implicitly reflects several
exposure pathways simultaneously within each
migration pathway. Nonetheless, there are
several exposure pathways delineated in
HEPRM that are not reflected in the HRS,
such as soil ingestion, contaminated plant
and aquatic biota ingestion, and dermal
contact with seepage.
In addition, the calculation algorithms used
are very different even when nearly
identical factors are employed. HEPRM is
fundamentally multiplicative in determining
the exposure pathway scores. For example,
the probability of ground water transport
score is the product of the scores for
aquifer proximity, net precipitation,
permeability, containment and leaching
potential. The corresponding calculation in
the HRS uses the sum of the factor values
for the first three factors (and a fourth
factor, physical state, not included in
HEPRM) all multiplied by the containment
factor value.
Further, the overall site score in HEPRM is
the sum of the exposure pathway scores while
the site score in the HRS is the root mean
square of the migration pathway scores.
The final significant difference between the
two systems is that HEPRM addresses human
health risks only while the HRS addresses
human health and environmental risks
121
-------
NEW YORK (Concluded)
DIFFERENCES FROM HRS: simultaneously. A separate system to assess
(Concluded) environmental risks (Biothreat Ranking
Model) is currently in the early stages of
development.
CONCLUSIONS: There are several characteristics of HEPRM
that should be investigated further for
possible adaptation into the HRS. These
characteristics are all related to the
exposure pathways not currently reflected in
the HRS, such as ingestion of soil and
ingestion of aquatic biota.
REFERENCES: Life Systems Inc., Briefing on Human
Exposure Potential Ranking Model (HEPRM),
Workshop on Prioritization Techniques/
Ranking Models, Oak Ridge Associated
Universities, July 15, 1986.
122
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B.4 Other Waste Site Ranking Systems
This section contains summaries of ten additional systems
developed to rank sites for various purposes. The systems are as
follows:
Arthur D. Little
Rating and Risk Assessment Methodology (Dames and Moore)
Hagerty, Pavoni, and Herr System
JRB Associates Model
LeGrand System
Monroe County Methodology
Olivieri and Eisenberg Assessment Methodology
Phillips, Nathwani, and Mooij Matrix
Rating Methodology Model
Objective Calculation Procedure
123
-------
ARTHUR D. LITTLE, INC.
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
Untitled
None has been identified
Arthur D. Little, Inc
Prepared for the Chemical Manufacturers
Association as an alternative approach to
the HRS.
The Arthur D. Little, Inc. (ADL) system was
developed as an alternative to the HRS.
Similar to the HRS, it is designed to rank
sites based on the relative risk they pose
to public health. The ADL system addresses
three pathways: ground water, surface water
and air, each evaluated on a scale of 0 to
100. The site score is the sum of the
pathway values, and ranges between 0 and
300. Three factor categories are evaluated
within each pathway: health effects, waste
reaching pathway, and population exposed.
Within these categories, values for several
factors are combined to form the category
values (see Table B-ll).
The health effects category is evaluated
based on the toxicity of the contaminants on
the site. The waste reaching pathway
category is evaluated differently in the
three pathways. Four subcategories are
evaluated in the ground water and surface
water pathway (three in the air pathway)
depending on whether there is evidence of
release from the site. The waste release
subcategory is evaluated based on the
factors listed in Table B-ll for each
applicable pathway. The subcategory value
is the sum of the factor values. In all
three pathways, if evidence of release
exists, the waste release subcategory value
is then multiplied by 6 to form the waste
reaching pathway value. If no evidence of
release exists for the ground water or
surface water pathways, the containment and
124
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TABLE B-ll
FACTORS INCLUDED IN ADL SYSTEM
Factors
1. Health Effects
Toxicity*
2. Waste Reaching Pathway
A. Waste Released
- Volatility
- Physical State*
- Persistence*
- Quantity*
- Net Precipitation*
- 1-Year 24-Hour Rainfall*
- Flood Potential
- Exposed Site Area
B. Evidence of Release*
C. Containment*
D. Waste Transported
- Depth to Aquifer*
- Distance to Surface Water*
- Permeability*
- Site /Slope Terrain*
3. Population Exposed
Water Use*
Nearby Land Use*
Distance to Water Use*
Distance to Land Use*
Population Affected*
Ground
Water
X
X
X
X
X
X
X
X
X
X
X
X
X
Pathway
Surface
Water
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Air
X
X
X
X
X
X
X
X
*Factors common to both ADL system and HRS.
Source: Arthur D. Little, Inc., 1981.
125
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ARTHUR D. LITTLE, INC. (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
waste transported subcategories are
evaluated. The containment value is simply
0 or 1, while the waste transported value is
the sum of the values of the factors listed
in Table B-ll. The waste released,
containment, and waste transported
subcategory values are then multiplied to
form the waste reaching pathway value. No
such provision for evaluating sites lacking
evidence of release is provided in the air
pathway; in such cases the waste reaching
pathway is assigned a score of zero.
The population exposed category is evaluated
as the sum of the applicable factor values.
The overall pathway score is the product of
the values for each of these three categories
(normalized to the 0 to 100 scale).
The ADL system and the HRS are similar in
many respects. Taken together, the health
effects and waste reaching pathway categories
in the ADL system generally correspond to
the HRS waste characteristics and release
categories. Combinatorially, they are nearly
identical. The ADL population exposed
category is nearly identical to the HRS
targets category. Also, both the ADL system
and the HRS evaluate the pathway value as
the product of the category values. Finally,
both systems utilize many of the same factors
in evaluating category values.
Despite the similarities between the two
systems, there are differences between
them. First, the overall site score in the
ADL system is the sum of the pathway scores,
while in the HRS, it is the root-mean-square
of the pathway scores. Second, in the ADL
system, persistence and quantity are
effectively multiplied by the toxicity score
(as are the remaining waste released values).
126
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ARTHUR D. LITTLE, INC. (Concluded)
DIFFERENCES FROM HRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
These factors are treated differently in the
HRS; persistence is incorporated into the
combined toxicity/persistence value, while
the quantity value is added to the toxicity/
persistence value. Third, the factor value
scales for rating many of the factors differ
between the systems. For example, quantity
in the ADL ground water pathway is evaluated
on a scale of 0 to 3, in increments of 1/2.
In the HRS ground water pathway, quantity is
evaluated on a scale of 0 to 8, in
increments of 1. Since the scores in both
systems are normalized, the only important
distinction here is in the increments.
Finally, three factors are included in the
ADL system that are not in the HRS system:
volatility (in the air pathway), flood
potential (in the surface water pathway),
and exposed site area.
The ADL system was developed as a
modification of the HRS. The ADL system was
evaluated by EPA before they HRS was
originally proposed and was found not to
rank sites as well as the HRS. No further
evaluation is warranted at this time.
Arthur D. Little, Inc., Proposed Revisions
to MITRE Model, Arthur D. Little, Inc.,
Cambridge, MA, September 23, 1981.
127
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DAMES AND MOORE
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS;
Rating and Risk Assessment Methodology
None identified
Dames and Moore
None identified
This system is an adaptation of the rating
methodology developed by JRB Associates,
Inc. It employs the same four rating
categories as the JRB methodology. Most of
the factors within each rating category are
identical to those in the JRB methodology,
although there are some additions and
deletions. This methodology differs from
the JRB methodology (and the HRS) in that
there is no aggregation of scores from the
four rating categories. Instead, the score
from each rating category is used to classify
that rating category as posing a low or high
risk. The low or high risk classifications
assigned to the four rating categories are
then combined to specify an overall site
classification ranging from very low risk
to very high risk (there are six such
categories).
The similarities discussed under the JRB
methodology also apply to the Dames and
Moore methodology. Similarities relate to
common rating factors.
Most of the differences discussed under the
JRB methodology also apply to the Dames and
Moore methodology. In addition, the Dames
and Moore methodology contains several
rating factors not included in the HRS
or the JRB methodology. These are
carcinogenicity/mutagenicity/teratogenicity;
bioaccumulation potential; type of evidence
of contamination; seismic activity; and
landfill cover condition, leachate
management, free liquids, and personnel
128
-------
DAMES AND MOORE (Concluded)
DIFFERENCES FROM HRS: training. In addition, the method of
(Concluded) aggregating the four rating categories
differs as described above.
CONCLUSIONS: The Dames and Moore methodology is an
adaptation of the JRB methodology that was
considered in the development of the HRS.
Thus, there is no need for further review of
most of the components of the methodology.
With regard to the additional rating factors
indicated above, the factors are either not
appropriate for inclusion in the HRS (e.g.,
personnel training) or not adequately defined
in their present form for inclusion in the
HRS (e.g., bioaccumulation potential).
REFERENCES: Dames and Moore, Overview of Methodology for
Rating the Potential for and Significance of
Ground and Surface Water Contamination from
Waste Disposal Sites, Bethesda, MD, Undated.
129
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HAGERTY, PAVONI, AND HERR SYSTEM
SYSTEM: Hagerty, Pavoni, and Herr
USER: None identified
DEVELOPER: D. Hagerty, J. Pavoni, and J. Herr
USE/STATUS: No longer used
GENERAL DESCRIPTION: The Hagerty, Pavoni and Herr (HPH) system is
an early ranking system (1973) that was
intended to rate potential ground water
impacts from landfilling of wastes. The HPH
system produces two separate rankings, one
based on waste characteristics and the other
based on site and target characteristics.
The former ranking uses five factors to rank
the relative hazardousness (in ground water)
of wastes that might be places in landfills
(these factors are from the PHL model
discussed in Appendix C). The latter ranking
uses ten other factors to separately rank
the potential of a landfill site itself to
result in impacts via the ground water
pathway. In both cases, computational
equations are used to assign values to each
factor. The factor values are summed to
produce each type of ranking.
The factors used to rank waste hazardousness
are: human toxicity, ground water toxicity,
disease transmission potential, biological
persistence, and waste mobility. The factor
used to rank the potential of a site to
cause ground water impacts are infiltration
potential, bottom leakage potential,
filtering capacity, adsorptive capacities,
organic content of ground water, buffering
capacity of ground water, travel distance,
ground water velocity, prevailing wind
direction, and population within 25 miles.
SIMILARITIES TO HRS: Two of the rating factors in the HPH system
are similar to factors in the HRS. The HPH
human toxicity factor is based on the Sax
130
-------
HAGERTY, PAVONI, AND HERS. SYSTEM (Concluded)
SIMILARITIES TO HRS:
(Concluded)
DIFFERENCES FROM HRS;
CONCLUSIONS:
REFERENCES:
rating scheme, as is the HRS toxicity factor.
Both systems also include a factor for the
population in the area of a site. However,
the HPH system uses the total population
within 25 miles of a site while the HRS
considers only that population within three
miles of the site that is using the aquifer
of concern.
The HPH system applies only to ground water
impacts from the landfilling of wastes. It
is not intended to evaluate the relative
threat posed by a site in terms of the
site's route characteristics, waste
characteristics, containment, and target.
Rather, it was intended to identify wastes
that may be of concern if they were
landfilled and site locations that could be
of concern if wastes were disposed there.
Except for the two factors discussed under
similarities to HRS, the other eight HPH
factors do not specifically correspond to
factors in the HRS. Also, the HPH system
uses computational equations rather than
factor scores to assign a value to each
rating factor.
The HPH is an early ranking system that was
considered in the development of later
ranking models. The additional factors in
the HPH system that are not in the HRS are
not adequately defined for inclusion in the
HRS. The HPH system does not warrant any
further evaluation.
Environ Corporation, Review and Analysis of
Hazard Ranking Scheme, Final Report, May 11,
1984.
Seller, L. and L. Canter, Summary of Selected
Ground Water Quality Impact Assessment
Methods, National Center for Ground Water
Research, Report No. NCGWR 80-3, Norman, OK,
1980.
131
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JRB ASSOCIATES, INC.
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
Methodology for Rating the Hazard Potential
of Waste Disposal Sites. Sometimes referred
to as the Rating Methodology Model.
None currently identified. Model originally
developed for EPA Office of Enforcement and
the Oil and Special Materials Division for
use in setting site investigation priorities
based on preliminary assessment data. Model
has been used as the basis for several other
systems including the Rating Methodology
Model (RMM), the Navy Confirmation Study
Ranking System (GSRS), and the Dames and
Moore system.
JRB Associates, Inc.
None identified.
The JRB model consists of 31 rating factors
grouped into four areas: receptors,
pathways, waste characteristics, and waste
management practices. These factors are
listed in Table B-12. Each rating factor is
scored on a scale of 0 to 3 and then
multiplied by a factor-specific multiplier.
These scores are then summed within each
area to form an area subscore. The area
subscores are then summed, divided by the
maximum possible score, and multiplied by
100 to form the site score.
The principal area of similarity between the
JRB model and the HRS is in the common
factors that both employ. These include
depth to ground water, net precipitation,
soil permeability, toxicity, waste quantity,
persistence, reactivity, and incompatibility.
The JRB model and the HRS have a number of
major differences. First, their overall
structures are different. In the HRS, each
pathway is treated separately; in the JRB
model the pathways are combined into one
scoring category. Furthermore, the JRB
132
-------
TABLE B-12
JRB ASSOCIATES, INC. MODEL RATING FACTORS
Factor Category Rating Factor
Receptor Distance to nearest drinking-water well
Distance to nearest off-site building
Land use/zoning
Critical environments
Pathways Evidence of contamination
Level of contamination
Type of contamination
Distance to nearest surface water
Depth to ground water
Net precipitation
Soil permeability
Bedrock permeability
Depth to bedrock
Waste Characteristics Toxicity
Radioactivity
Persistence
Ignitability
Reactivity
Corrosiveness
Solubility
Volatility
Physical state
Waste Management Practices Site security
Hazardous waste quantity
Total waste quantity
Waste incompatibility
Use of liners
Use of leachate collection systems
Use of gas collection systems
Use and condition of containers
Source: Kufs et al., 1980a.
133
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JKB ASSOCIATES, INC. (Concluded)
DIFFERENCES FROM HRS: model does not address the air pathway. Also,
(Concluded) containment is treated as a single factor,
not as a pathway specific factor. Second,
the scores are combined in different fashions
in the two systems. In the JRB model, the
site score is a weighted sum of the factor
scores while the HRS site score is the root
mean square of weighted sums of factor
scores. Thus, the JRB model is a linear
model, the HRS is not. Finally, the JRB
model includes a number of factors in the
ranking that the HRS does not, e.g., bedrock
permeability, depth to bedrock, waste
ignitability, corrosiveness, and volatility.
There are numerous other less important
differences between the two systems.
CONCLUSIONS: The JRB model was assessed during the
development of the HRS (47 FR 10975,
March 12, 1982). The additional factors
present in the JRB model, but not in the HRS,
were considered during development of the HRS
but were rejected because they could not be
adequately defined for use in the HRS or
because other factors were judged to provide
better measures of relative risk.
REFERENCES: Kufs, Charles et al., Methodology for Rating
the Hazard Potential of Waste Disposal Sites,
(Draft Final Report), JRB Associates, Inc.,
McLean, VA, May 5, 1980a.
Kufs, Charles et al., "Rating the Hazard
Potential of Waste Disposal Sites,"
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, 1980b,
pp. 30-41.
134
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SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
THE LEGRAND SYSTEM
Untitled
No specific users could be identified.
Modifications of the current LeGrand system
(and its predecessor) are used by the State
of Connecticut and in the Olivier! and
Eisenberg Assessment Methodology
Harry E. LeGrand
Designed to evaluate the acceptability of
locations for use as possible disposal sites.
The LeGrand system is designed to evaluate
the acceptability of a proposed disposal site
based on the potential for ground water
contamination at the site. The system
produces a vector of site characteristics
(i.e., the "site description") to be used in
the evaluation process. The complete
evaluation process is not algorithmic, but
provides for subjective judgment based on the
factors contained in the site description.
The site description is based on the
following characteristics:
Distance between contamination source and
water supply
Depth to water table
Water table gradient
Permeability-sorption
Confidence in accuracy of results
Miscellaneous identifiers
Each of these characteristics is evaluated on
a separate scale which is adapted from the
original LeGrand system (LeGrand, 1964).
A combined numerical rating for the site is
calculated as the sum of the ratings for the
first four characteristics listed above. An
additional factor is included based on the
degree of seriousness of the hazard using a
hazard potential matrix. The degree of
135
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THE LEGRAND SYSTEM (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
seriousness is evaluated based on the degree
of aquifer sensitivity and the degree of
contaminant severity. The former factor is
evaluated based on the type of geologic
material underlying the site. The latter is
based either on the source of the wastes
(e.g., organic or inorganic chemical
manufacturing) or the type of wastes (e.g.,
municipal waste) to be disposed of on the
site. The inclusion of the degree of
seriousness factor completes the "natural"
site description (see Table B-13).
The aquifer sensitivity and contaminant
severity factors are also used to define the
"PAR" site description, a numerical vector
describing a benchmark for interpreting the
natural site description. The PAR vector is
subtracted from the natural vector and the
resulting vector summed (as applicable) to
form the situation rating. The situation
rating is then used in a rating table to
assess, qualitatively, the probability of
contamination and the degree of acceptability
of the site. Engineering characteristics of
the site can be reflected in the PAR
description and hence in the situation rating,
although the exact procedures for doing so
are not provided in the references.
There are few similarities between the LeGrand
system and the HRS. Both systems use some
common factors (e.g., distance between site
and water supply, and depth to ground water)
and both systems distinguish between the type
of receiving water body (e.g., well or
stream). Finally, both systems evaluate the
probability that the site will contaminate
the ground water. In all cases, however, the
two system treat these factors differently.
136
-------
TABLE B-13
SUMMARY EXAMPLE OF LEGRAND SITE DESCRIPTIONS FOR
A COUNTY LANDFILL IN THE NORTH CAROLINA PIEDMONT
Factor
Distance between contamination source and water supply
(2,200 feet)
Depth to water table (less than 2 feet)
Water table gradient (less than 2 percent)
Permeability-sorption (30 feet sandy clay soil and soft
rock over poorly permeable consolidated rock)
Confidence in accuracy of results
Miscellaneous
(Creek as contamination target)
(Other factors: potential for mounding)
Sum of first four numerical values (2+8+3+4= 17)
Factor
Value
4F
M
17
Site Numerical Description (i.e., all of the
above factor values)
Aquifer sensitivity (moderately fractured
crystalline rock)
Contaminant Severity (municipal landfill)
Degree of Seriousness (moderately high)
"Natural" Site Description
"PAR" Site Description
Situation Rating
Probability of Contamination
Acceptability
Source: LeGrand, 1980.
137
17 2 8 3 4F B S M
Moderately sensitive
Moderately high
E
17 2 8 3 4F B S M +E
16 2 4
Unknown
Unknown
-------
THE LEGRAND SYSTEM (Continued)
DIFFERENCES FROM HRS:
CONCLUSIONS:
There are numerous differences between the
two systems. First, the LeGrand system is
not a ranking system. It provides a
semi-numerical description of a site to be
used by decision-makers to evaluate the
acceptability of the site for use as a waste
disposal site. Second, the LeGrand system
addresses the potential for ground water
contamination only. No consideration is
given to the potential for surface water,
air, or soil contamination. Third, the
LeGrand system does not consider the
potential impact of the contamination on
human health. No consideration is given to
the types and numbers of potential
contamination targets. Fourth, the LeGrand
system provides a nonquantitative assessment
of the accuracy of the rating. No such
factor is included in the HRS. Fifth, many
of the factors in the LeGrand system are very
subjective or nonquantitative, e.g., the
degree of aquifer sensitivity and contaminant
severity. Sixth, the LeGrand system does not
consider the actual degree of the hazard
posed by the waste contaminants at the site.
Contaminant severity is assessed using vague,
non-site-specific waste classes. Finally,
the LeGrand system contains some factors not
included in the HRS, particularly, water
table gradient and sorption potential.
The LeGrand system and the HRS are very
different systems, both in their structures
and in the uses for which they were
developed. The LeGrand system can be
modified or adapted to assist in ranking
uncontrolled wastes sites and has been used
in such a fashion as indicated above.
The concepts embedded in three factors in the
LeGrand system should be evaluated further.
These are the permeability-sorption factor,
the aquifer sensitivity factors and the water
138
-------
THE LEGRAND SYSTEM (Concluded)
CONCLUSIONS: table gradient factor. These factors,
(Concluded) however, are not themselves adequately
defined for use in the HRS. In addition, the
concept of including a qualitative assessment
of the accuracy of the rating results should
be investigated further.
REFERENCES: LeGrand, Harry E., A Standardized System for
Evaluating Waste-Disposal Sites; A Manual to
Accompany Description and Rating Charts,
National Water Well Association, 1980.
LeGrand, H. E., "System for Evaluation of
Contamination Potential of Some Waste
Disposal Sites," JAWWA. 1964, pp. 959-974.
139
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MONROE COUNTY METHODOLOGY
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
Monroe County Methodology (MCM)
Monroe County Environmental Management
Council, Rochester, NY
Monroe County Environmental Management
Council and State University of New York
(SUNY) at Geneseo under contract to U.S. EPA
Environmental Monitoring Systems Laboratory,
Las Vegas, NV
Currently used by Monroe County Environmental
Management Council to identify and assign
priorities to sites for future investigation.
The MCM is intended to supplement ranking
systems such as LeGrand and JRB by
identifying and ranking sites that might be
contaminated with hazardous wastes for
further investigation. The MCM uses historic
aerial photographs as primary data,
supplemented by other data. Based on the
historic record, sites are identified and
classified into six site activity categories:
identifiable, possible, unspecified, lagoons,
auto junkyards and salvage areas, and
suspicious. A site activity record is then
compiled. The site activity record covers a
large number of factors including the
historic activity at site based on photos,
site acreage, record of disposal activity,
type of waste disposed (e.g., acids,
radioactive waste, herbicides), adjacent land
use, well information, site features (e.g.,
depth to ground water). A geologic analysis
of the area is performed leading to
development of geologic overlay maps. A
geologic ranking sheet is prepared addressing:
overburden geology, estimated permeability,
relief/geomorphology, depth to ground water,
ground water gradient, bedrock character,
soil properties, texture and behavior. The
geologic ranking system is based on the
presumed effect on the overall hazard that
140
-------
MONROE COUNTY METHODOLOGY (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES:
each geologic factor would have: increase
hazard, intermediate (uncertain), decrease
hazard. A decision on how to proceed with
the site is made based on the site activity
record combined with the geologic ranking and
an assessment of the threat to drinking
water. For example, a decision to conduct a
complete monitoring program would be made for
a site with a history of waste disposal, a
high geologic ranking and an identified
threat to ground water. Sites that could
impact nearby wells are immediately referred
to authorities for testing. Other sites are
prioritized using a matrix for ranking
geologic and land use impact, size and type
of activity. Information on this matrix
procedure is not available in the reference.
The MCM addresses some of the same factors as
the HRS, e.g., depth to ground water, distance
to nearest well.
The MCM is designed to identify and rank
sites that might contain hazardous waste for
further investigation. It is thus intended
to be applied at an earlier stage than the
HRS. The MCM addresses ground water only and
thus is more dependent on geologic data/
factors. The system does not apparently
produce a single score for a site but rather
classifies sites and prioritizes them based
on their classification. The two systems are
not directly comparable.
The geologic ranking system appears to
warrant further evaluation for possible
application to the HRS.
Nelson, Ann R., Louise A. Hartshorn and
Richard A. Young, A Methodology to Inventory,
Classify, and Prioritize Uncontrolled Waste
Disposal Sites (EPA-600/4-83-050),
Environmental Monitoring Systems Laboratory,
U.S. Environmental Protection Agency,
Las Vegas, NV, October 1983.
141
-------
MONROE COUNTY METHODOLOGY (Concluded)
REFERENCES: Nelson, Ann B. and Richard A. Young,
(Concluded) "Location and Prioritizing of Abandoned Dump
Sites for Future Investigations," 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. 52-62.
142
-------
OLIVIERI AND EISENBERG ASSESSMENT METHODOLOGY
SYSTEM:
Untitled
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
San Francisco Regional Water Quality Control
Board and the Santa Clara Valley Water
District
Dr. Adam W. Olivieri and Dr. Don M. Eisenberg
Currently used by the San Francisco Regional
Water Quality Control Board to rank hazardous
material contamination sites in terms of
their relative potential for ground water
contamination.
The Olivieri and Eisenberg assessment
methodology is designed to rank hazardous
material contamination sites containing
organic solvents in terms of their relative
potential for ground water contamination.
Sites are ranked with regard to two areas:
site sensitivity and contamination severity.
Site sensitivity rates the susceptibility of
the site to ground water contamination. Site
sensitivity is rated using four factor
categories that have been developed based on
the LeGrand system (see Table B-13).
Table B-14 lists the four factor categories
and the 14 specific hydrogeologic and water
use factors within these factor categories.
Contamination severity rates the severity and
potential for the release from the site to
contaminate ground water. Contamination
severity is rated using three factor
categories. Table B-14 lists the three
factor categories and the nine specific
factors within these factor categories. Four
of these factors, the three toxicity factors
and the bioaccumulation factor, are based
upon the chemical hazard rating scheme
developed by the State of Michigan (see
Figure B-6 and Table B-8).
143
-------
TABLE B-14
OLIVIERI AND EISENBERG ASSESSMENT METHODOLOGY RATING FACTORS
SITE SENSITIVITY FACTORS
Distance to Point of Water Use
Closest Public Well Downgradient
Closest Public Well Not Downgradient
Closest Private Well Downgradient
Intensity of Present Water Use
Population Served by Wells in the Downgradient Square Mile
Number of Public Wells within 1,500 Feet Downgradient
Number of Private Wells beyond 1,500 Feet Downgradient, but
Within 1 Square Mile
Number of Private Wells Within 1 Square Mile Downgradient
Depth to Water Table
Depth to Shallowest Ground Water
Depth to Shallowest Useable Ground Water (Potential Supply)
Depth to Shallowest Currently-Used Potable Water (Existing
Supply)
Permeability (Travel Time) of Zone 0 to 50 Feet Below Surface
Permeability (Travel Time) of Zone 50 to 150 Feet Below
Surface
Permeability (Travel Time) of Zone 150 to 300 Feet Below
Surface
Gradient of Shallow Water Table
Ground Water Table Gradient
CONTAMINANT SEVERITY FACTORS
Toxicity
Acute
Chronic
Mutagenic
144
-------
TABLE B-14 (Concluded)
CONTAMINANT SEVERITY FACTORS (Concluded)
Physical-Chemical Properties
Soil Sorption
Bioaccumulation
Magnitude of Contamination
Highest Contaminant Concentration in Ground Water
Highest Contaminant Concentration in Soil
Contaminant Plume Dimension
Number of Chemicals
Source: Olivier! and Eisenberg, 1985.
145
-------
OLIVIER! AND EISENBERG ASSESSMENT METHODOLOGY (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS;
The scores for each factor are summed to give
site sensitivity and containment severity
ratings. At the user's discretion, these two
ratings may either be summed to give one
overall rating for the site or may be used
separately in a two-dimensional graphical
display as an aid to ranking the site.
The Olivier! and Eisenberg Assessment
Methodology is intended to evaluate the
relative ground water threat posed by sites
containing organic solvents. As such, the
methodology corresponds to the HRS ground
water pathway. The Olivier! and Eisenberg
Assessment Methodology and the HRS contain
five types of factors that are similar in
concept, but which are defined, evaluated,
and weighted differently. These are:
distance to nearest well, population served
by wells, depth to aquifer, permeability, and
toxicity.
There are several major differences between
the Olivieri and Eisenberg Assessment
Methodology and the HRS. First, the
assessment methodology applies only to the
ground water pathway and only to releases of
organic solvents. Second, the methodology
uses different definitions and measures for
factors that are similar in concept to those
in the HRS. Third, the methodology contains
several factors that are not present in the
HRS, e.g., contaminant carcinogenicity,
contaminant mutagenicity, contaminant
bioaccumulation potential, plume dimension,
highest contaminant concentration in plume or
soil, number of chemicals present, gradient
of ground water table, and soil sorption
constant. Finally, the methods used to
combine factor scores to form the overall
site scores differs between the systems. The
Olivieri and Eisenberg methodology is
additive. Further, the actual method of
calculating the site score from the site
146
-------
OLIVIERI AND EISENBERG ASSESSMENT METHODOLOGY (Concluded)
DIFFERENCES FROM HRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
sensitivity and contaminant severity scores
is left up to the user. The HRS sums within
categories, but multiplies the category values
to form the pathway values. Additionally,
the HRS utilizes a root-mean-square
calculation to form the site score.
The factors listed above that are contained
in the this methodology, but not in the HRS,
should be examined for possible application
in the HRS.
Olivier!, Adam W. et al., Assessment of
Contamination from Leaks of Hazardous
Materials in the Santa Clara Basin 205j
Report, San Francisco Regional Water Quality
Control Board, SEEHRL University of
California, Berkeley and Santa Clara Valley
Water District, February 1985.
Olivier!, A. W. and D. M. Eisenberg, "A
Methodology for Ranking Risk of Groundwater
Contamination from Hazardous Material Sites,"
ASCE National Conference on Environmental
Engineering, Los Angeles, CA, June 25-27,
1984.
147
-------
PHILLIPS, NATHWANI, AND MOOIJ MATRIX
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
Phillips, Nathwani, and Mooij
None identified
C. Phillips, J. Nathwani, and H. Mooij
No current uses could be identified.
The Phillips, Nathwani, and Mooij (PNM)
matrix is intended to rank potential ground
water impacts from the land disposal of
wastes. The PNM matrix produces three types
of rankings: a waste hazardousness ranking,
a soil-site ranking (which corresponds to the
HRS ground water route characteristics
category), and a combined waste-soil-site
ranking. Ten factors (4 of which are
modified from the PHL model discussed in
Section C.I of Appendix C) are used to rank
the relative hazardousness (in ground water)
of wastes that might be land disposed. Seven
other factors (6 of which are modified from
the LeGrand Model) are used to rank the
potential of a land disposal site to result
in impacts to ground water. The 17 factors
are confined in a matrix to rank the
waste-soil-site interaction. Computational
equations are used to assign values to each
factor.
The six factors not included in the PNL model
that are used to rank waste hazardousness
are: chemical persistence, sorption,
viscosity, solubility, acidity/basicity, and
waste application rate. The one soil-site
factor not included in the LeGrand model is
infiltration.
The similarities discussed under the PHL
model and the LeGrand model also apply to the
PNM matrix. Similarities relate to common
rating factors.
The differences discussed under the PHL model
and the LeGrand model also apply to the PNM
148
-------
PHILLIPS, NATHWANI, AND MOOIJ MATRIX (Concluded)
DIFFERENCES FROM HRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
matrix. Furthermore, the PNM matrix contains
six additional rating factors noted above
that are not included in the HRS or the other
two models. In addition, the PNM matrix
applies only to ground water impacts from the
land disposal of wastes. In evaluating land
disposal sites, the PNM matrix considers
only route characteristics and waste
characteristics. Targets and waste
containment factors are not considered. The
PNM matrix also uses computational equations
rather than factor scores to assign a value
to each rating factor. Furthermore, several
factors require data derived from site-
specific field experiments before they can be
scored (e.g., sorption, chemical persistence).
The additional factors in the PNM matrix that
are not in the HRS are not adequately defined
for inclusion in the HRS. The PNM matrix
does not warrant any further evaluation.
Seller, L. and L. Canter, Summary of Selected
Ground Water Quality Impact Assessment
Methods, National Center for Ground Water
Research, Report No. NCGWR 80-3, Norman, OK,
1980.
149
-------
RATING METHODOLOGY MODEL
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
Rating Methodology Model
None identified
Undetermined. Apparently based on JRB
Associates, Inc. model.
None could be identified. Model as presented
in reference is not useable.
The Rating Methodology Model (RMM) is an
adaptation of the JRB Associates, Inc. model
and is designed to evaluate the risk of
hazardous waste sites and to produce a single
score reflecting this risk. The RMM
incorporates four types of factors:
receptors, pathways, waste characteristics,
and waste management practices. Little
information is available in the reference on
the factors and computational approaches
employed in the RMM. In the model, scores
are determined for each of several evaluation
parameters. These parameter scores are
multiplied by weighting factors to form site
parameter scores. These site parameters
scores are then summed and normalized to form
a site score.
Most of the factors identified in the RMM
appear to be addressed in the HRS. Receptor
parameters appear to include population and
facilities, land and water use, critical
habitats and biota. Pathways appear to
include air, water and soil. Waste
characteristics common to both the RMM and
HRS appear to include quantity, condition of
wastes, toxicity, ignitability, reactivity,
corrosivity and persistence. See JRB
Associates, Inc. for a further discussion of
similarities.
The RMM considers more waste characteristics
than the HRS: mobility, carcinogenicity,
volatility, radioactivity, and solubility.
150
-------
RATING METHODOLOGY MODEL (Concluded)
DIFFERENCES FROM HRS:
(Concluded)
CONCLUSIONS:
REFERENCES:
The computational approach appears to be
different; the score is based on the sum of
the site parameter scores rather than on the
product of pathway scores, as in the HRS.
See JRB Associates, Inc. for a further
discussion of differences.
The model appears to be more of a general
approach for a ranking system rather than a
ranking system itself. The operational
definition of the additional waste
characteristics that appear in RMM are not
adequate for consideration in the HRS.
Berger, Isabell S., "Determination of Risk
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. 23-26.
151
-------
TRC ENVIRONMENTAL CONSULTANTS, INC.
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS;
Untitled. Author refers to approach as an
Objective Calculation Procedure (OCP).
None has been identified. System is
presented in conference proceedings.
TRC Environmental Consultants, Inc., under
subcontract to GCA/Technology Division,
which is under contract to EPA.
None could be identified. System as
presented in reference is not useable.
The author presents a calculation equation
designed to estimate the total risk from a
waste site over a defined time period. The
equation reflects the potency of chemicals
released, the relationship between ambient
concentrations of the chemicals and the
ingestion/inhalation rates of the chemicals,
population and the exposure concentration.
The author also compares his equation to the
approach taken in the HRS.
Many of the factors included in the HRS are
reflected in the OCP. For example, in the
ground water pathway, the OCP reflects
observed release, route characteristics,
containment, physical state of the waste,
contaminant persistence, contaminant
toxicity/infectiousness, waste quantity,
ground water use, target population and
distance to nearest well downgradient.
The OCP is not a scoring system but can be
used as the basis for one. The author
states that the OCP does not discount future
risks while the HRS "strikes a balance" by
combining scores for waste quantity and
release rate. The author also states that
the OCP emphasizes "what is right" about a
site while the HRS emphasizes "what is
wrong" with the site.
152
-------
TRC ENVIRONMENTAL CONSULTANTS, INC. (Concluded)
CONCLUSIONS: The OCP presents a risk-based alternative to
the value-based approach taken in the HRS.
Its concept could be implemented, but is
subject to more severe data availability
problems than the HRS. The equations
presented are also significantly simplified,
possibly too much to be acceptable. Some of
the factors included in the OCP should be
reviewed for inclusion in the HRS (e.g.,
contaminant mobility); however, the approach
taken in the OCP is incompatible with the
HRS.
REFERENCES: 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.
153
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APPENDIX C
CHEMICAL HAZARD RANKING SYSTEMS
Section C.I contains summaries for seven systems developed for
use in ranking chemical hazards. Each summary contains information
on the following topics:
Name
User
Developer
Use/Status
General Description
Similarities to HRS
Differences from HRS
Conclusions
References
Section C.2 identifies 52 other chemical hazard ranking systems.
155
-------
C.I Individual Systems Summaries
This section presents individual summaries of seven chemical
hazard ranking systems:
Action Alert System
Barring Model
CERCLA Reportable Quantities
Clement Associates
PHL Model
RCRA Hazardous Waste Scheduling Methodology
Superfund Public Health Evaluation System
156
-------
ACTION ALERT SYSTEM
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
CONCLUSION:
Action Alert System
United States Environmental Protection
Agency, Monitoring and Data Support Division,
Office of Water Regulations and Standards.
Arthur D. Little, Inc.
The Action Alert System was designed and
used as a planning tool to evaluate 129
priority pollutants. It is no longer being
used.
The Action Alert System was developed as a
preliminary screening tool for use in
prioritizing chemicals, primarily the 129
priority pollutants, for further study or
regulatory action based on the potential
risk they pose to humans and aquatic life.
The Action Alert System was intended to
provide a rapid and consistent mechanism for
screening chemicals based upon partial
information about their presence in the
environment and the associated potential
hazards. The screening provides either a
qualitative indication of the degree of
concern warranted for each chemical (i.e.,
low or high) or a specification of the
additional data required to make such a
determination.
None, see differences.
The Action Alert System is intended to
prioritize chemicals for further study
or regulatory action based on risk
approximations. It is not intended to rank
the threat posed by waste sites, nor even to
rank the degree of hazard of various
chemicals.
The Action Alert System is not applicable to
ranking the potential threat posed by
hazardous waste sites.
157
-------
ACTION ALERT SYSTEM (Concluded)
REFERENCES: U.S. Environmental Protection Agency, An
Approach to Prioritization of Environmental
Pollutants; The Action Alert System, Final
Draft Report, U.S. Environmental Protection
Agency, June 1980 (revised January 1982).
Slimak, Mike, U.S. Environmental Protection
Agency, personal communication to Carol
Burger, The MITRE Corporation, September 18,
1986.
158
-------
BARRING MODEL
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
Barring Model
Environmental Protection Agency
Booz-Allen Applied Research, Inc.
No longer used.
The Barring Model is an early hazard ranking
model (1973) that was intended to identify a
representative list of hazardous substances
and to rank the effects of these substances
in terms of air, water, and land pollution
hazards. Four factors addressing toxic
effects to human and other populations,
flammable hazard, explosive hazard, and
reactive hazard were used to calculate a
Total Effects Rating (TER) for a hazardous
substance. The TER was a weighted sum of
the four factors values. The Hazard Rating
was calculated as the product of the TER and
a Hazard Extent Rating which was based on
annual production and consumer distribution
of the hazardous substances. Over 500
substances, many of which were warfare
agents, were rated using the model.
Several of the factors in the Barring Model
are similar to some of the factors in the
waste characteristics category of the HRS
air and fire and explosion pathways (e.g.,
toxicity, reactivity). However, they are
not specified or weighted in the same way.
There are a number of differences between
the HRS waste characteristics categories and
the Barring Model. The most important is
that by the nature of its ranking factors,
the Barring Model seems intended to focus on
ranking explosive and ignitable wastes rather
than on ranking the many types of hazardous
substances present at release sites. Its
application primarily to warfare agents
provides further evidence of this focus.
159
-------
BARRING MODEL (Concluded)
CONCLUSION: The Barring Model was an early ranking model
that was considered in the development of
more recent ranking models. It does not
warrant any further evaluation.
REFERENCES: Environ Corporation, Review and Analysis of
Hazard Ranking Schemes, Final Report,
May 11, 1984.
160
-------
CERCLA REPORTABLE QUANTITIES (RQ)
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
Reportable Quantities
Environmental Protection Agency, Office of
Solid Waste
Environmental Monitoring and Services, Inc.
Used to determine quantities of releases
that must be reported to EPA pursuant to
Sections 102(a) and 102(b) of CERCLA.
The purpose of this system is to determine
the minimum quantity of a hazardous substance
spill or release that must be reported to
EPA. Initially, each substance is assigned
a vector of RQ values based on its
reactivity, ignitability, acute toxicity,
aquatic toxicity, and chronic toxicity.
Reactivity is evaluated based on the ability
of the substance to react with water and/or
itself. RQ values for reactivity range from
10 to 5,000. Ignitability is evaluated,
using the same scale as reactivity, based on
the flash point and boiling point of the
substance. Acute toxicity is evaluated
based on the LC5Q or LD5Q of the
substance administered by ingestion,
inhalation, or dermal contact, as applicable.
Acute toxicity values range from 1 to
5,000. For example, substances with an oral
LDjjQ less than 0.1 mg/kg, a dermal LD5Q
less than 0.04 mg/kg, or an inhalation
LC5Q less than 0.04 ppm are assigned an RQ
value of 1. The acute toxicity value for a
substance is the minimum of the values for
its possible exposure routes. Aquatic
toxicity is evaluated using the LC5Q of the
substance, again on the full scale of 1 to
5,000. The method for evaluating chronic
toxicity is more complex. Chronic toxicity
is evaluated based on a composite of the
overall minimum effective dose (MED) of the
substance for the three possible exposure
161
-------
CERCLA REPORTABLE QUANTITIES (RQ) (Continued)
GENERAL DESCRIPTION:
(Concluded)
SIMILARITIES TO HRS:
routes (ingestion, inhalation, and dermal)
and a numerical assessment of the severity
of the effects caused by repeated or
continuous exposure. MED is converted to a
scale of 1 to 10, using the inverse of the
logarithm of the MED. Severity is also
evaluated on a scale of 1 to 10, with minor
effects being assigned low scores and major
effects, high scores.
The product of the MED and severity scores
is calculated and an RQ value is assigned
using the following scale:
1 to 5:
6 to 20:
21 to 40:
41 to 80:
81 to 100:
RQ = 5000
RQ = 1000
RQ = 100
RQ = 10
RQ = 1
The lowest of the RQ values determined for
the five criteria is taken as the "primary
criteria" RQ value. This value may then be
adjusted, based on the persistence of the
substance in the environment to obtain the
statutory RQ value. Persistence is defined
in terms of the potential of the substance
for undergoing biodegradation, hydrolysis,
and photolysis.
There are three areas of similarity
between the RQ system and the HRS waste
characteristics evaluation procedure.
First, both systems consider the acute
toxicity of a substance. Also, both systems
consider chronic toxicity, the RQ systems
explicitly, the HRS implicitly to the extent
that Sax considers it. The second similarity
lies in the way that each considers acute
toxicity. Both systems assign values to
substance based on the IB$Q or LC^g of
the substance, as applicable, although the
two systems use different scales. Finally,
both systems address the ignitability and
reactivity of substances.
162
-------
CERCLA REPORTABLE QUANTITIES (RQ) (Concluded)
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES:
There are several important differences
between the systems. First, as stated
above, the procedures used in evaluating the
common factors are different in some
details. Second, and more importantly, the
RQ system considers a number of chronic
effects (including teratogenicity) not
addressed in Sax, and hence excluded from
consideration in the HRS. Third, the HRS
employs different values depending on the
migration pathway under consideration. The
RQ system does not consider migration
pathways, only modes of exposure. Further,
the HRS assumes a direct relationship
between the mode of exposure and the
migration pathway, e.g., ingestion is
assumed to be the mode of exposure in the
ground water pathway while inhalation is
assumed in the air pathway. Given this
assumption, the HRS treats modes of exposure
separately while the RQ value is based on
the minimum of the values for the potential
modes of exposure.
The RQ system contains many features that
are either addressed indirectly or lacking
in the HRS waste characteristics category.
The systems should be evaluated in detail.
Environmental Monitoring and Services, Inc.,
Technical Background Document to Support
Rulemaking Pursuant to CERCLA Section 102,
Volume 1, U.S. Environmental Protection
Agency, Washington, DC, 1985.
48 FR 12552, May 25, 1983.
50 FR 13456, April 4, 1985.
163
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CLEMENT ASSOCIATES
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS;
CONCLUSIONS:
REFERENCES:
Untitled
Clement Associates, Inc.
Clement Associates, Inc.
The system has been used to determine the
relative risk ranking of 32 chemicals.
The methodology provides a score for a
pollutant that represents the relative
probability that a given hazard will occur
in exposed populations per unit dose of the
pollutant. The effects that are scored are
carcinogenicity, teratogenicity, reproductive
toxicity, mutagenicity, hepatotoxicity,
renal toxicity, neurobehavioral toxicity and
effects in other organ systems. A score is
assigned for each of these forms of toxicity
for each pollutants. The score is a product
of two measures of risk:
Probability that the pollutant is toxic to
humans, based on inferences from animal
data, or on direct measures of human
toxicity.
Probability of occurrence of the toxic
effect in exposed humans per unit dose of
exposure, assuming that the agent is a
human toxicant.
The sole similarity between the Clement
Associates, Inc. system and the HRS is that
both reflect acute toxicity.
The methodology is an alternative to the Sax
rating scheme used in the HRS toxicity factor.
The methodology needs to be further evaluated
to assess its applicability to the HRS.
Clement Associates, Inc., Toxics Integration
Program; Scoring of Selected Pollutants for
Relative Risk, Washington, DC, June 26, 1981.
164
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PHL MODEL
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES:
PHL Model
None has been identified.
J. Pavoni, D. Hagerty, and L. Lee
No longer used.
The PHL Model is an early ranking model
(1972) that was intended to rank the
hazardousness of substances placed in
landfills. The model consists of five
ranking factors that were summed: toxicity,
ground water toxicity, disease transmission
potential, biodegradability, and mobility.
Computational equations were used to assign
a value to each factor.
The toxicity factor in the PHL Model is
based on the Sax rating schemes.
The PHL Model applies only to substances
placed in landfills. It contains three
factors not included in the HRS: disease
transmission potential, ground water
toxicity, and mobility. Ground water
toxicity of a substance is calculated based
on the smallest concentration known to have
caused injury to man or biota. Mobility is
calculated based on the ionic charge or net
charge of a substance. The PHL Model also
uses computational equations rather than
factor scores to assign a value to each
rating factor.
The PHL is an early ranking model that was
considered in the development of later
ranking models. It does not warrant any
further evaluation.
Environ Corporation, Review and Analysis of
Hazard Ranking Schemes, Final Report,
May 11, 1984.
165
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RCRA HAZARDOUS WASTE SCHEDULING METHODOLOGY
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
RCRA Hazardous Waste Scheduling Methodology
Environmental Protection Agency, Office of
Solid Waste
Environ Corporation
The methodology has been proposed by EPA to
be used to schedule RCRA listed hazardous
waste streams for land disposal prohibition
determinations, as required by the Hazardous
and Solid Waste Amendments of 1984. The
methodology was proposed in the Federal
Register (50 FR 23250, May 31, 1985) and has
not yet been promulgated as final.
The methodology ranks the toxic potential of
waste constituents. The toxicity ranking
scheme incorporates measures of both acute
and chronic toxicity and can be applied to a
broad range of chemicals with a wide variety
of data bases. The 11)50 *s use(^ as a
measure of acute toxicity. The chronic
toxic potential of a compound is summarized
in a single term, designated the Equivalent
Dose Estimate (EDE). Acceptable daily
intakes (ADIs) and unit cancer risks (UCRs)
serve as the basis for deriving the EDEs for
noncarcinogenic and carcinogenic compounds,
respectively. For those compounds with
limited data bases, additional uncertainty
factors are applied to derive the EDE. For
compounds with extremely limited data bases,
EDEs are assigned by analogy to structurally
similar compounds or are estimated by
applying a large standardization factor to a
measure of acute toxicity. The waste
constituents are assigned a chronic toxicity
score of 1 to 9 based on the estimate of
chronic toxic potential (the EDE). This
score is adjusted upward by 1 if a compound
possesses high acute toxicity according to
the established criteria. Thus, the
resulting toxicity scores range from 1 to 10.
166
-------
RCRA HAZARDOUS WASTE SCHEDULING METHODOLOGY (Concluded)
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES :
The EDE is an alternative to the Sax rating
scheme used in the HRS toxicity factor.
The EDE is based on ADIs and UCRs and not on
the Sax rating scheme. As such it is an
alternative to the HRS toxicity factor.
The methodology needs to be further evaluated
for possible application in the HRS.
Environ Corporation, Documentation for the
Development of Toxicity and Volume Scores
for the Purpose of Scheduling Hazardous
Wastes, Final Report, Washington, DC,
March 28, 1985.
167
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SUPERFUND PUBLIC HEALTH EVALUATION (SPHE) SYSTEM
SYSTEM: Superfund Public Health Evaluation (SPHE)
System
USER: U.S. Environmental Protection Agency, Office
of Solid Waste
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
IGF Incorporated
Used to evaluate the threat to public health
from NPL sites and to develop remedial action
goals.
The SPHE system is a method for estimating
the public health impacts of NPL sites. It
is used as part of the remedial response
process, as an aid in identifying, evaluating,
and selecting remedial alternatives. As
such, it is not a chemical hazard ranking
system. However, Step 1 of the SPHE system
addresses the selection of chemicals, from
among all those chemicals at the site, as
"indicator chemicals" to be used in further
site evaluation. This portion of the system
was examined as a chemical hazard ranking
system.
The SPHE system uses an "indicator score" to
identify indicator chemicals. The indicator
score is the product of the measured (or
estimated) concentration of the chemical at
the site times a "toxicity constant." These
toxicity constants are benchmark ambient
concentrations derived separately for air,
water, and soil. The toxicity constants are
in units of inverse concentration (e.g., 1/mg
or m^/mg). Separate toxicity constants are
carcinogenic and noncarcinogenic effects.
Thus, a particular chemical may have as
many as six toxicity constants; one for
carcinogenic effects in each of three routes
and one for noncarcinogenic effects in each
of three routes. Acute toxicity is not
considered in the SPHE system.
168
-------
SUPERFUND PUBLIC HEALTH EVALUATION (SPHE) SYSTEM (Continued)
GENERAL DESCRIPTION: Noncarcinogenic toxicity factors are derived
(Concluded) using estimates of the minimum effective
dose (MED, ^. or MED,. u ., . ^, as
(oral) (inhalation)'
applicable) of the chemical that induces an
irreversible effect and the severity factor
(RVe) developed for the chemical as part
of the CERCLA Reportable Quantities (RQ)
system. The route-specific noncarcinogenic
toxicity constants are calculated as follows:
water: ^ = 2 x RVe/MED(oral)
soil: stn = 0.0001 x RVe/MED(oral)
air: atn = 20 x RVe/MED(inhalation)
Carcinogenic toxicity constants are derived in a
similar fashion using the dose to experimental
animals that induces a particular tumor to occur
in 10 percent more of the exposed animals than in
the control group (ED-j^). The route-specific
carcinogenic toxicity constants are calculated as
follows:
water: wfcc = 2/70 x ED10
soil: s_ - 0.0001/70 x EDin
tc iu
air: atc = 20/70 x ED10
The constants in all of the above equations
reflect reference human values (70 kilograms body
weight, 20 m^/day inhalation rate, 2 I/day water
ingestion rate, and 100 mg/day soil ingestion
rate) used to convert dose units into ambient
concentration units.
Several other factors are considered subjectively
in determining the indicator chemicals, in
addition to the indicator score: persistence
of the chemical, weight of evidence for
carcinogenicity, water solubility, vapor pressure,
Henry's constant, and organic carbon partition
coefficient.
169
-------
SUPERFUND PUBLIC HEALTH EVALUATION (SPHE) SYSTEM (Concluded)
SIMILARITIES TO HRS: The only similarities between the HRS and
the SPHE systems are that both address
noncarcinogenic chronic effects and
persistence on a route-specific (or
pathway-specific) basis.
DIFFERENCES FROM HRS: There are numerous differences between the
HRS and the SPHE system. First, the HRS
toxicity score depends heavily on the
relative acute toxicity of the chemical in
question. The SPHE system does not address
acute toxicity. Second, the SPHE system
considers carcinogenic effects, while the
HRS does not. Third, the SPHE system
indirectly considers the mobility of the
chemicals, in terms of their basic chemical
characteristics. No consideration is given
to contaminant mobility in the HRS.
Finally, the SPHE system includes the
measured or estimated chemical concentration
at the site in question in determining the
indicator score. The HRS uses concentration
data only to establish observed releases.
CONCLUSIONS: The approach to deriving toxicity constants
in the SPHE should be evaluated in terms of
possible adaptation for use in the HRS. The
remaining aspects of the SPHE are either
not sufficiently defined (e.g., use of
persistence and mobility information) to be
employed in the HRS or require data beyond
the scope of a current site inspection.
REFERENCES: ICF Incorporated, Superfund Public Health
Evaluation Manual, (Draft), ICF Incorporated,
Washington, DC, October 1, 1985.
170
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C.2 Other Systems Identified
This section presents summaries of two reports that reviewed
chemical hazard ranking systems. The first report reviewed
23 systems, while the second reviewed 34 systems. Five of the
systems reviewed are included in both sets of reviews.
171
-------
REVIEW OF 23 CHEMICAL HAZARD RANKING SCHEMES
SYSTEM:
USER:
DEVELOPER:
USE/STATUS
GENERAL DESCRIPTION:
Twenty-three schemes for ranking the hazard
associated with wastes and waste
constituents are reviewed in the indicated
reference (see Table C-l for a list of these
23 schemes). (Note that 34 other systems
which were developed more than 10 years ago
were also briefly reviewed in the indicated
reference. Most of these schemes were
developed for use as screening tools for
prioritizing chemicals for further study.
They were not meant to rank the relative
hazard of chemicals. Most of these early
systems were considered in the development
of the current systems included in the
review. Consequently, they are not
considered further in this summary.)
All but the last two systems listed in
Table C-l are used by or proposed for use by
a variety of Federal agencies, States, and
foreign governments. These last two systems
are early systems that are no longer being
used.
These systems have been developed by a
variety of Federal agencies, States, foreign
governments, trade associations, and private
organizations.
All but the last two systems in Table C-l
have been developed within the last 10 years
and are either currently being used or have
been proposed for use in calculating the
hazard (i.e., relative risk) associated with
waste streams and waste constituents.
The 23 hazard ranking schemes fall into
three categories: classification schemes,
risk analysis models, and numerical
schemes. Thirteen of the hazard ranking
schemes are classification schemes, 4 are
models, and 6 are numerical schemes. The
classification schemes use specific technical
criteria (e.g., 11)50 of less than x^ to
172
-------
TABLE C-l
LIST OF 23 CHEMICAL HAZARD RANKING SYSTEMS
INCLUDED IN ENVIRON CORPORATION REVIEW
EPA HAZARDOUS WASTE/CHEMICAL RANKING SCHEMES
Selected Criteria Processing
Assessment of Air Emissions from Hazardous Waste Treatment,
Storage and Disposal Facilities
RCRA Risk-Cost Analysis Model
Toxicity Scoring System Using RTECS Data Base
Integrated Environment Management Program
OTS Chemical Scoring System
OTHER FEDERAL SCHEMES
U.S. Army Hazard Multi-Media Estimating and Ranking Scheme
STATE HAZARDOUS WASTE RANKING SCHEMES
Alaska
California
Louisiana
Maryland
Michigan
Rhode Island
Washington
FOREIGN RANKING SCHEMES
EEC Ranking Algorithm for Water Pollutants
OTHER RANKING SCHEMES
Chemical Manufacturers Association
Dow Chemical
Soap & Detergent Association
American Paper Institute and National Forest Products
Association
National Paint and Coating Association
Weyerhauser Company
Booz-Allen Barring Model
PHL Model
173
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REVIEW OF 23 CHEMICAL HAZARD RANKING SCHEMES (Concluded)
GENERAL DESCRIPTION:
SIMILARITIES TO HRS:
DIFFERENCES FROM HRS:
CONCLUSIONS:
REFERENCES:
categorize wastes into specific hazard
classes such as low, medium, and high hazard.
The modeling schemes are basically risk
analysis models, employing complex
submodels, and have to be run on a computer.
The numerical schemes use numerical scales
to assign values to factors based on
specified hazard characteristics of the
waste (e.g., acute toxicity, persistence,
carcinogenicity). The value for each hazard
characteristic is weighted and combined to
obtain a single numerical hazard value for
the waste or waste constituent.
Both the numerical schemes and
classification schemes represent
alternatives to the Sax rating scheme used
to assign values to the HRS toxicity factor.
The modeling schemes are not comparable to
the HRS toxicity factor (e.g., see the
discussion of the RCRA Risk-Cost Policy
Model in Appendix B).
The various numerical and classification
schemes all need to be evaluated further to
assess their applicability to the HRS. One
of the major concerns with these schemes is
the availability of the data required by
them to rank the large number of substances
that are hazardous under CERCLA.
Environ Corporation, Review and Analysis of
Hazard Ranking Schemes, Final Report,
May 11, 1984.
174
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REVIEW OF 34 SCORING SYSTEMS FOR CHEMICAL HAZARD ASSESSMENT
SYSTEM:
USER:
DEVELOPER:
USE/STATUS:
GENERAL DESCRIPTION:
Thirty-four scoring systems for chemical
hazard assessment are identified and reviewed
in the indicated reference (see Table C-2
for a list of these 34 schemes).
These systems are used by a variety of
Federal agencies, quasi-governmental
organizations (e.g., National Cancer
Institute, National Academy of Science),
States, foreign governments, and industries
(see Table C-2).
These systems have been developed by a
variety of Federal agencies, quasi-
governmental organizations, States, and
private organizations (see Table C-2).
The scoring systems reviewed are intended to
be used for one of two purposes: to select
or prioritize chemicals for testing or to
select or prioritize chemicals for regulation
or control. The scoring systems reviewed
have been used to score pesticides, new
chemicals, food contaminants, synthetic
organic chemicals, and hazardous wastes.
Some of the scoring systems were also
developed to deal with specific
environmental compartments such as the
atmosphere or aquatic life. Some were
developed to assess risk to specific
populations such as employees of selected
industries, users of consumer products, or
residents near a landfill. The various
scoring systems have been used to score
anywhere from 6 to 28,000 chemicals;
however, only 8 systems have been applied to
over 500 chemicals.
For each of the 34 scoring systems, the
review article identifies why the system was
developed, who developed the system, who the
system was developed for, the factors used
in the scoring, the algorithms by which
scores are combined, and the universe of
substances to which they have been applied.
175
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TABLE C-2
LIST OF 34 IDENTIFIED SCORING SYSTEMS FOR CHEMICAL HAZARD ASSESSMENT
System
User
Developer
Pesticide Manufacturing
Air Prioritization
Sequential Testing for
Toxicity Classification
Index of Exposure
Chemical Hazard
Ranking System
System for Evaluation
of the Hazards of Bulk
Water Transport of
Industrial Chemicals
Barring Model
Select Organic Compounds
Hazardous to Environment
Ranking Algorithm for
EEC Water Pollution
Setting Priorities for
R&D on Army Chemicals
System for Rapid Ranking
of Environmental Pollutants
Estimating Hazard of
Chemical Substances to
Aquatic Life
Estimation of Toxic
HazardA Decision Tree
EPA/IERL
Not identified
EPA
CPSC
U.S. Coast Guard
Not identified
National Science
Foundation
EEC
USAMRDC,
Fort Derrick
EPA/ORD
Not identified
Industry
Monsanto
Eastman Kodak Co.
Auerbach Associates
ITT Research Institute
NAS
Booz-Allen Applied
Research
Stanford Research
Institute
Stanford Research
Institute
Stanford Research
Institute
Stanford Research
Institute
ASTM, Committee D-19
Flavor and Extract
Manufacturer's Associates
176
-------
TABLE C-2 (Continued)
System
TSCA-ITC Scoring
System Workshop
Action Alert System
Scoring of Organic
User
EPA/ITC
EPA/OWRS
EPA/OAQPS
Developer
Enviro Control, Inc.
Arthur D. Little, Inc.
The MITRE Corporation
Pollutants
Ranking of Environmental
Contaminants for Bioassay
Priority
PHL Model
Hazard Evaluation
Procedure for Potentially
Toxic Chemicals
Selection of Chemicals
for Inclusion in a Trend
Monitoring
National Cancer
Institute
Not identified
UNEP
Federal Republic
of Germany
RCRA Risk-Cost Policy Model EPA/OSW
ITC Scoring for
Biological Effects
Ranking of Food
Contaminants
Rapid Screening and
Identification of
Airborne Carcinogens
Michigan Critical
Materials Register
EPA/ITC
OTA
State of
California
Michigan
Department of
Natural Resources
Stanford Research
Institute
Pavoni, Hagerty, and Lee
Monitoring and Assessment
Research Center
The MITRE Corporation
ICF Inc., Clement
Associates, SCS Engineers
Clement Associates
Clement Associates
SAI
State of Michigan
177
-------
TABLE C-2 (Concluded)
System
User
Developer
National Occupational
Hazard Survey
Assessment of Oncogenic
Potential
ITC Scoring for Exposure
Order of Commercial
Chemicals on NIOSH
Suspected Carcinogens List
Identification of
High-Risk Occupational
Groups and Industrial
Processes
OECD Ecotoxicology
Testing Scheme
Chemical Scoring System
Development
Environmental Scoring of
Chemicals
NIOSH
Not identified
EPA/ITC
Not identified
NIOSH
DCCP/NCI
EPA/OPTS
EPA/OPTS
EPA/OPTS
Ranking Animal Carcinogens Not identified
NIOSH
Hooker Chemical
Clement Associates
EPA/OPTS
Tracer Jitco
Hazard Assessment by a
Qualitative System
French Ministere
de 1'Environment
Battelle
Oak Ridge National
Lab
Oak Ridge National
Lab
R. Squire
Association Chimie
et Ecologie
Source: Hushon and Kornreich, 1984.
178
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REVIEW OF 34 SCORING SYSTEMS FOR CHEMICAL HAZARD ASSESSMENT
(Continued)
SIMILARITIES:
DIFFERENCES FROM HRS:
CONCLUSIONS:
Based on the review, only two of the scoring
systems appear to have any relevance to the
HRS. The systems are the following:
Barring Model
PHL Model
Each is used to estimate the hazard of
chemicals disposed in waste sites. As such
they may provide alternatives to the Sax
rating scheme used in the HRS toxicity
factor.
Most of the 34 scoring systems are not
comparable to the HRS. Sixteen are meant as
screening tools for use in prioritizing
chemicals, especially new chemicals or
suspected carcinogens, for more intensive
scientific study. These systems are not
meant to rank the relative hazard of
chemicals for use in regulatory programs.
Fifteen of the scoring systems are meant to
identify high risk chemicals based on
exposure by selected populations. As such
these scoring systems focus on many factors
not relevant to the HRS such as chemical
production volume, fraction of production
lost, use patterns, production emission
sources and rates, and population exposed
through production or use.
One scoring system is designed to test how
well aquatic tests predict hazard potential.
Only two of the scoring systems identified
in the review need to be evaluated further
to assess their applicability to the HRS.
These are the Barring Model and the PHL
Model. They are reviewed in Section C.I of
Appendix C.
179
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REVIEW OF 34 SCORING SYSTEMS FOR CHEMICAL HAZARD ASSESSMENT
(Concluded)
REFERENCES: Hushon, Judith and Mary Kornreich, Scoring
Systems for Hazard Assessment, Hazard
Assessment of Chemicals; Current
Developments, Volume 3, pp. 63-109, Academic
Press, Inc., 1984.
180
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