Baltimore
Integrated Environmental Management Project:
Phase I Report
Executive Summary
^eP **^
Regulatory Integration Division
Office of Policy Analysis (PM-220)
Office of Policy, Planning, and Evaluation
U.S. Environmental Protection Agency
May 1987
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EXECUTIVE SUMMARY
Baltimore
Integrated Environmental Management Project
Phase I Report
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This report describes the first phase of the two-phase
Baltimore Integrated Environmental Management Project (IEMP) con-
ducted by the Regulatory Integration Division of the Environmen-
tal Protection Agency (EPA). EPA initiated the project in
Baltimore as part of its pursuit of new approaches to environmen-
tal management and policy. The purpose of the IEMP is to identi-
fy and assess the significance of a selected set of environmental
issues that concern management, to set priorities for action
among these issues, and to assist local authorities in respondinq
to environmental problems they have identified.
The IEMP approach is based in part on risk assessment and on
risk management. It uses estimates of risk (that is, the prob-
ability of adverse effects) as the common measure for comparing
problems_and setting priorities among issues affecting human
health, involving different pollutants, sources, and exposure
pathways. The risk assessments are used in risk management, a
process in which policymakers balance programs to reduce risks
against available resources to support those programs. In its
simplest form, it requires an examination of how large the risks
are, how much the risks can be reduced by various regulatory
controls, and the cost of controls. Also, the projects are
intended to involve all responsible local parties and agencies in
actually managing and coordinating the projects, ensuring that
issues of greatest local concern are adequately addressed.
Projects typically have two phases. In the first the
decision-making structure of the project is established, key
environmental issues are identified, and priorities for detailed
study are set among them. In the second the IEMP studies the
priority issues in greater depth and develops potential strate-
gies for their control or resolution.
THE BALTIMORE IEMP
Description of the Baltimore IEMP
The Baltimore IEMP is a cooperative effort among EPA and
the governments of the State of Maryland, the City of Baltimore,
Baltimore County, and Anne Arundel County. The Baltimore area
was chosen, in large part, because EPA and local officials wanted
to explore better ways to identify, assess, and manage the human
health risks of environmental pollutants in the area. It repre-
sents the second of five, full-scale geographic projects initi-
ated to date. Most important, the Baltimore IEMP is different
from other IEMP projects in that the authority for project direc^
tion and policies and resource allocation resides with state a"nd
local officials.Though EPA has set the overall study objectives
and the level of resources for the project, it has played only
a support and advisory role in overall project management. This
ES-1
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experiment in local participation in project management of the
Baltimore project is intended to achieve greater local commitment
and to test a different approach to local environmental management.
Emphasis is on local control rather than federally-directed quan-
titative analysis of environmental problems.
The study area (described in Chapter II) covers Baltimore
City, which includes the Port of Baltimore, and Baltimore and
Anne Arundel Counties (see Figure ES-1). The greater Baltimore
area is representative of older, industrialized cities of the
East Coast in transition from smokestack to more diversified,
service economies. Its present environmental concerns derive
largely from the industrial and commercial activities that are
ongoing and of its past and from present-day cars and trucks.
The Institutional Structure of the IEMP
The institutional structure (described in Chapter III) of the
Baltimore IEMP evolved in response to EPA's decision to test the
hypothesis that delegating management authority will lead to
active local participation and commitment to project objectives..
The Management Committee (MC) is the vehicle for State and local
participation and provides project and policy direction. The
Technical Advisory Committee (TAG), composed of local and State
environmental and public health professionals, provides advice to
the MC. EPA provides administrative, technical, and analytical
support. In the concluding stage of Phase I, the general involve-
ment in the IEMP widened to nearly 60 people representing industry,
public interest groups, government, and academia. They serve on
workgroups established to develop and excute workplans for Phase
II issues. For the second phase of the project, the Management
Committee has constituted a Risk Assessment Review Panel, con-
sisting of scientists from Johns Hopkins University, to provide the
MC with scientific and technical advice on questions related to
risk assessment.
The Process for Setting Priorities in Phase I
The purpose of Phase I was to identify issues for further
study in Phase II. The Baltimore IEMP set priorities among the
issues on the basis of available information, supplemented by
data from a brief ambient air monitoring effort conducted by the
EPA. It was not a strictly scientific endeavor, but rather an
exercise in policy analysis using scientific information; expert
judgment; and reasonable assumptions, where gaps in data existed.
Two sets of criteria were used: primary decision criteria which
relied heavily upon scientific data and professional expertise
and secondary criteria which drew on pragmatic considerations
by local officials regarding the best use of study resources.
ES-2
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FIGURE ES-1
BALTIMORE I.E.M.P. STUDY AREA
PENNSYLVANIA
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The TAG had the responsibility for developing both the ini-
tial list of environmental issues and the priority-setting proc-
edures that would be used in ranking issues on this list. The
MC had the final say in the adequacy of the initial list and in
the selection and relative funding of issues for Phase II study.
Defining the Scope of the Project
The scope of the project evolved from numerous EPA discus-
sions with State and local governments. Toxic pollutants were
chosen because of the general consensus that the greatest analy-
tic contribution could be made in this area. The same discus-
sions persuaded the Baltimore IEMP to include ecological effects
of both conventional and other than conventional water pollutants
and exclude issues that could not reasonably be handled with
anticipated project resources. (e.g., conventional air pollu-
tants, occupational exposures, food chain exposures).
Selecting the Initial List of Environmental Issues
The Technical Advisory Committee drew up a list of thirty-
two topics (described in Chapter IV) for preliminary screening,
based on their previous experience with pollution problems and
on professional judgment. The issues dealt with risks to human
health and potential to cause damage to ecosystems and natural
resources, such as ground water. The TAG did not consider the
thirty-two issues a comprehensive list of the most pressing envi-
ronmental problems in Baltimore. This process was neither de-
signed nor ever intended to identify systematically every envi-
ronmental problem; no process could do so gxven data limitations.
Developing the Method for Setting Priorities in the Initial List
of Issues
The problem for the TAG lay in developing a procedure that
permitted comparing different environmental problems (e.g., sub-
stances that may cause cancers versus industrial effluents that
disrupt ecosystems), yet could make best use of available scienti-
fic information.
Rather than making this type of tradeoff immediately, the
TAG decided to rank the issues against three separate measures
of risk: risk to human health, potential to cause adverse ecolo-
gical impact, and potential adverse impacts to ground-water.
Each type of risk required a different method for determining
the ranking of these issues with regard to the measure. The
problem of comparing different environmental problems (e.g., human
health vs. ecological impact) was deferred until after the eval-
uation of issues within the categories of human health, ecological
ES-3
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impact, and impact on ground-water resources. As it happened,
selection of issues for Phase II study did not require making
these tradeoffs.
In developing measurements of human health risk for air
pollutants, the human health subcommittee used quantitative risk
assessment for carcinogens. For non-cancer health risks, the
subcommittee used EPA Reference Doses (RfDs) that indicate what
levels of a pollutant may pose noncancer risk. For indoor air,
the subcommittee used best professional judgment regarding the
risks because the only existing data were for exposure levels in
other cities. The work of the subcommittee is further described
in Chapter V.
The ground-water subcommittee developed an index (described
in Chapter VI) to rank the relative importance of various sources
and classes of pollutants that may damage ground-water resources.
The subcommittee relied primarily on their professional judgment
to assign scores to different potential threats to ground-water
which in turn were used to establish their relative ranking on the
index. The index had two basic components capturing different
aspects of the possible effect of a potential source on ground
water: pollution and economic impact.
The ecological subcommittee used indexing as the priority-
setting tool for Phase I. The process (described in Chapter VII)
compares existing pollutant concentrations in the ambient water
to generally applicable reference values.
All three of the TAC's methods included appraisals of the
degree of uncertainty associated with the analysis of each prob-
lem. These appraisals were qualitative and based on the best
judgment of the committee members.
Ranking the Initial Issues against the Primary Criteria
For setting priorities among potential health problems, the
human health subcommittee defined the primary criterion as aggre-
gate expected increases in the incidence of disease. On the ba-
sis of this criterion and the quality of the available data, the
subcommittee recommended five issues to the full TAG for study
in Phase II: trihalomethanes in drinking water; toxic volatile
organic compounds of low molecular weight organics; benzene;
metals in air; and indoor air pollution.
The ecological subcommittee recommended three issues to the
full TAG based on the criterion of potential ecological impact:
toxic metals in ambient water; previously contaminated sediments
as a source of water contamination; and bioaccumulation of toxics
in aquatic organisms.
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Figure ES-2
Flow Chart of How the TAG and the Workgroups
Pared down the List of Issues from Ten to Five
10 Issues
Combine and
Redefine to
6 Issues
Apply Secondary
Criteria
Human Health Risk Subcommittee
Benzene ——— _ ^
ToKic Air Pollution——^^^fr-TOHIO Air Pollution Tonic Air Pollution
Trihalomethanes in Trihalomethanes in DW\1
Drinking Water
Metals in Air-
Indoor Air Pollui
Ecological impact Subcommittee
Indoor Air Pollution
Indoor Air Pollution
Metals
Sediments
Bioaccumulation oT
TOHJCS in
Aquatic Organises
Metals in the
Environment
Harbor
Metals in the
Environment
Harbor
Ground-Water Resource /S am age Subcommittee
Metals in Ground'
Water
Underground Storage
Tanks
Underground Storage
Tanks
Underground Storage
Tanks
Redo
Primary /Secondary
Criteria for Metals
Resulting in Final
List of Issues
Toxic Air Pollution
Indoor Air Pollution
Underground Storage
Tanks
1\Continued in Phase II for comparison, but not for further study'
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After evaluating source categories against the criterion of
potential ground-water impact, the ground-water resource subcom-
mittee recommended two issues to the full TAG: pollution of
ground-water by metals and pollution from underground storage
tanks.
In summary, the first part of the priority-setting process
reduced the initial list of thirty-two issues to ten (see Figure
ES-2). Overlap among the ten study topics allowed the TAG to con-
dense these into six issues. Benzene and toxic air pollution
became one issue, toxic air pollution. The three issues relat-
ing to metals became multi-media metals. The two remaining eco-
logical problems became the focus of a study of the Harbor. The
remaining 3 topics were indoor air pollution, underground storage
tanks, and trihalomethanes (THMs) in drinking water.
Ranking Issues against the Secondary Criteria
The TAG then completed the priority-setting process through
the application of secondary criteria. These included:
1) Likelihood of making a significant contribution to lo-
cal environmental management through a Phase II study;
2) Lack of duplication with existing analyses or control
programs;
3) Technical and political feasibility if implementing
controls for each issue studied; and
4) Feasibility of performing the analysis within time and
fiscal constraints.
Of the six topics the TAG determined that trihalomethanes in
drinking water did not meet the first criterion. The exposures,
risks, and controls for THMs are well understood for purposes of
risk management and, further, are under study by EPA for national
regulations. Thus THMs were not included as a Phase II study
topic (although it remains as a comparison point for the Phase II
risk estimates). The other five topics remained for Phase II.
(See Figure ES-2)
ANALYTIC RESULTS
A summary of the analytic results developed in Phase I is
presented in this section. However, it is important to under-
stand the major assumptions on which the results are based. This
is particularly true in this case, as the analysis was used only
to select issues for further study—not to support risk manage-
ment decisions or control strategies nor to document a local
problem^
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Limitations and Caveats of the Analysis
The reader should keep in mind that the risk assessments do
not directly examine disease incidence in the local population.
Quantitative risk assessment uses models that are conceptually
simple. Ambient monitoring data or, wVere these do not exist,
estimated ambient levels based upon soiree emission estimates,
are used in conjunction with exposure factors to estimate human
exposure to each substance under study. These estimates of expo-
sure in turn are combined with toxicological estimates of potency
to yield quantitative estimates of individual risk. These are
expressed as the incremental probability of disease incidence
(not death) that would conservatively be expected to result from
that exposure. Combined with data on population densities, the
information on individual risk can be extrapolated to yield numer-
ical estimates of disease incidence in the population attributable
to exposures to each pollutant.
The models are deliberately designed to yield conservative
estimates both of individual risk and of aggregate disease inci-
dence to average ambient values for the pollutant in question
over long periods of constant exposure. Their primary usefulness
is thus in setting priorities and allocating resources rather
than in predicting absolute risk. For each of the pollutants
analyzed, the methodology is more likely to overstate risk than
to understate it. However, they do not take into account inter-
mittent peak levels of pollutants to which an individual may be
exposed during his or her daily activities and which, through
dilution in the ambient air, are not well represented by ambient
average daily concentrations. Where these are expected to occur
frequently, the models may be of limited use. The models also
cannot handle possible synergistic or antagonistic effects of
simultaneous exposure to more than one pollutant and rely on
simple additive assumptions, consistent with EPA guidelines.
Consequently, our analyses cannot provide definitive answers
regarding past, or current risks. They allow only a rough estima-
tion of health effects or environmental conditions that may occur
in the future for the issues analyzed. Where situations that
contribute to these health effects or environmental conditions
change, these estimates of risk will no longer apply. Because
of the many uncertainties and potential omissions, we cannot say
whether our evaluation of risks to health and the environment are
under- or over-estimated. For those chemicals for which the IEMP
was able to make quantitative estimates of risks and for the ex-
posure scenarios presented, the risks are more likely to be over-
estimated than underestimated. To the extent that toxic chemi-
cals about which we currently know little have been left out,
risks may be underestimated.
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Also, the scope of the study unavoidably excludes numerous
issues that may be of environmental importance. Only a very small
number of pollutants were examined for their health and environ-
mental effects. The IEMP, for example, did not estimate risks
from occupational exposures or from the ingestion of pesticide
contamination of foods. Furthermore, the estimates of pollutant
concentrations in the various media were severely limited by the
lack of actual monitoring data. Nor were risks from chance occur-
rences, such as accidental spills or releases of toxic chemicals,
studied. Also, we did not monitor ground-water resources for con-
tamination or conduct a comprehensive survey of the health of the
harbor. Finally, the examination of hospital records of chil-
dren's exposure to lead in dust suggests only that an immediate
health concern exists for a limited population. The health con-
cern cannot be generalized to the population as a whole.
Risk assessment in Phase I was conducted as part of an exer-
cise in policy analysis to help local decision-makers set priori-
ties. The goal of our risk assessments is to determine which
issues were suitable for a more detailed examination of risks and
control options in Phase II. The results which we present are
not statements about the incidence of disease in the Baltimore
area.
The results of Phase I of the IEMP must, therefore, not be
looked" uporT as the products of a comprehensive appraisal of envi-
ronmental risks in the Baltimore area.Thevalueo?theIEMP
methodology is that it allows an evaluation and comparison of the
risks from chemicals about which we know something. Management
of these risks, based on the best current information, can pro-
ceed, while research continues on the effects of chemicals about
which little is currently known.
Results of the Analyses
Before summarizing the results of our analysis of human
health effects, we want to provide some general guidance to help
understand them. We feel it is important to provide a point of
reference, a baseline, for our numerical estimates of the health
effects. Thus, from Maryland statistics for cancer, we know there
were 4285 cancer deaths in 1984 in the study area (see Chapter II,
Table II-4). In 1983* the American Cancer Society estimated there
were 1.92 cancer cases for every cancer death. Using these two
factors, we derived an estimated baseline incidence of 8227 cases
for the study area.
Human health issue; Organics in the Ambient Air
The limited air monitoring conducted by the IEMP and review
of monitoring conducted by the Maryland Air Management Administra-
tion provided estimates of ambient levels for a small number of
noncriteria pollutants. The IEMP also conducted limited air dis-
perison modeling to estimate the contribution of emissions from
publicly-owned treatment works (POTWs) to ambient levels.
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Of the organic compounds evaluated in the ambient air, the
highest measured concentrations were for benzene, xylene, toluene,
and ethyl benzene. Lead had the highest value for the metals.
Comparison of levels of pollutants at different monitoring sites
suggests that the concentrations of some organics and metals can
vary significantly throughout the Baltimore area.
The highest identifiable cancer risk from organics is attri-
butable to benzene. Benzene alone accounted for about two-thirds
of the upper-bound estimate (assuming the EPA standard of 70 years
of exposure) of roughly 3 excess cancer cases a year from the
organic air toxics examined. Table ES-1 summarizes these results.1
Monitoring data suggested that there may also be increased
risk of noncancer health effects for benzene and chloroform.
Human health issue: Metals in the Ambient Air
For the metals examined, health risks were much lower than
the organics, with the possible exception of chromium.The
health risk from exposure to chromium depends on the species of
chromium in the air. The techniques employed in determining
chromium levels in the Baltimore area, however, do not allow for
determining the relative concentrations of hexavalent chromium, a
potent carcinogen, to trivalent chromium, a relatively weak car-
cinogen. Under the worst case, and unlikely, assumption that all
detected chromium is hexavalent, the upper-bound estimate (assuming
the EPA standard of 70 years of exposure) of cancer risk is roughly
four excess cancer cases a year. This roughly comparable to the
total risk from the organics described above. Table ES-2 summari-
zes these results.
The upper-bound estimate (assuming the EPA standard of 70
years of exposure) of cancer risks to individuals in areas with
the highest concentrations of the pollutants examined (both for
metals and for organics) did not exceed one chance in ten thousand
for any pollutant, except where one assumes that all detected
chromium was hexavalent. In that case, the upper-bound estimate
(assuming the EPA standard of 70 years of exposure) risk would be
four chances out of ten thousand.
Potentencyestimates used were from EPA's Cancer Assessment
Group (GAG). They have received extensive peer review. The
exception is 1,2-Dichloropropane. For this compound, toxicolo-
gical staff of the Regulatory Integration developed the potency
score using CAG methodology. Review of this score has been
more limited.
ES-8
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Table E5-1
BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS
UPPER-BOUND ESTIMATES OF ANNUAL EXCESS CANCER INCIDENCE:
ORGANICS IN THE AMBIENT AIR
PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
PHASE II RESEARCH AGENDA
Upper-Bound Annual Cases^
Pollutant 1985 Revised
(weight of evidence)3 Analysis4 1986 5
Benzene (A) 1.6 1.8
Trichloroethylene (B2) 0.1 0.02
Percnloroethylene (82) 0.2 0.1
1,2-Oichloroethane (82) 0.04 0.1
Chloroform (82) 0.2 0.4
Carbon Tetrachloride (82) 0.3 0.3
1,2-Oichloropropane (C) 0.1 0.1
Total 2.5 2.8
JTHE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON
CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUND
ESTIMATES. BECAUSE OF LIMITATIONS IN DATA AND METHODS IN
SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULA-
TIONS AND POLLUTANT SELECTION, RISK ESTIMATES CRE CALCU-
LATED AS AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF
ACTUAL CANCER RISKS IN BALTIMORE. ACTUAL RISKS MAY BE SIG-
NIFICANTLY LOWER; IN FACT, THEY COULD BE ZERO. THE PROPER
FUNCTION OF THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT
AND EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS
EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES IN THE
STUDY AREA IN 1984 IS 8,000 CASES. (SEE II-8 AND 9.) THIS
NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE IN UNDER-
STANDING THE RISK ESTIMATES PROVIDED. IN ADDITION, THE
RISK ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING
THE TOTAL UPPER-BOUND CANCER RISKS FROM ALL POLLUTANTS IN
ANY PARTICULAR MEDIUM. THEY DO NOT TAKE INTO ACCOUNT ALL
POLLUTANTS THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES
OF THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING
PATHWAYS OR EXPOSURES OF SHORT DURATION TO RELATIVELY HIGH
DOSES.
*EPA weight-of-evidence classifications: A = human carcino-
gen; 82 = probable carcinogen; C = possible carcinogen.
(See Appendix A for more detail.)
*The incidence estimates listed in this column were calcu-
lated using cancer unit risk values developed in 1985.
'The incidence estimates listed in this column were calcu-
lated using current (5/86) cancer unit risk values.
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Table ES-2
BALTIMORE IEMP PRELIMINARY
RISK SCREENING RESULTS
UPPER-BOUND ESTIMATES OF ANNUAL
EXCESS CANCER INCIDENCE:
METALS IN THE AMBIENT AIR
PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
PHASE IL RESEARCH AGENDA
Upper-Bound Annual Cases1,2
Pollutant 1985 Revised
(weight of evidence)3 Analysis4 19865
ChroniuM (A)
—Total hexavalent 4.2 4.2
—SOX hexavalent 2.1 2.1
—10X hexavalent 0.4 0.4
.-IX hexavalent 0.04 0.04
—OX hexavalent 0.00 0.00
CadniiM6 (Bl) 0.00 to O.OS 0.00 to 0.04
Total 0.00 to 4.25 0.00 to 4.24
*THE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED
ON CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE
UPPER-BOUND ESTIMATES. BECAUSE OF LIMITATIONS IN DATA
AND METHODS IN SEVERAL AREAS OF THE ANALYSIS, SUCH AS
EXPOSURE CALCULATIONS AND POLLUTANT SELECTION, RISK
ESTIMATES MERE CALCULATED AS AIDS TO POLICY DEVELOP-
MENT, NOT AS PREDICTIONS OF ACTUAL CANCER RISKS IN
BALTIMORE. ACTUAL RISKS MAY BE SIGNIFICANTLY LONER;
IN FACT, THEY COULD BE ZERO. THE PROPER FUNCTION OF
THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND
EVALUATE ISSUES AND SET PRIORITIES FOR THE TOPICS
EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES
IN THE STUDY AREA IN 1984 IS 8,000 CASES. (SEE II-8
AND 9.) THIS NUMBER SHOULD SERVE ONLY AS A POINT OF
REFERENCE 04 UNDERSTAND INC THE RISK ESTIMATES
PROVIDED. IN ADDITION, THE RISK ESTIMATES SHOULD
NOT BE INTERPRETED AS REPRESENTING THE TOTAL UPPER-
BOUND CANCER RISKS FROM ALL POLLUTANTS IN ANY PARTICU-
LAR MEDIUM. THEY DO NOT TAKE INTO ACCOUNT ALL POLLU-
TANTS THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES
OF THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS
INVOLVING PATHWAYS OR EXPOSURES OF SHORT DURATION TO
RELATIVELY HIGH DOSES.
^EPA weight-of-evidance classifications i A * huasn
carcinogen; 81 a probable carcinogen. (See Appendix A
for lore detail.)
*The incidence estimates liated in this column Mere
calculated using cancer unit risk factors available in
1985.
"The incidence eatinatea liated in this column were
calculated using current (5/86) unit risk factors.
^Measured cadaiuB concentrations were below detection
liaits. For screening purposes only, we calculated
risks to human health asauaing a range in embient
concentration fro* zero to the detection linit.
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Human health issue: Trihalomethanes in drinking water
The subcommittee examined the health risks from ingestion of
trihalomethanes (particularly chloroform) in the water from public
drinking water treatment plants.
The upper-bound estimate (assuming the EPA standard of 70
years of exposure) of cancer risk to individuals is 5 chances in
100,00 for either plant (using the 1985 unit risk factor for
chloroform). The chloroform levels correspond to an upper-bound
estimate (assuming the EPA standard of 70 years of exposure) of
less than one annual excess cancer case from ingestion for each
plant (using 1985 cancer potency data). No other monitored
pollutants of carcinogenic concern were detected. Table ES-3
summarizes these results.
None of the pollutants examined in drinking water appear to
pose noncancer health effects at the concentrations found, with
the possible exception of lead. As mentioned earlier with re-
gard to lead in the ambient air, total exposure from all path-
ways is essential in estimating the health risks posed by this
substance. Though lead in the public water supply is present at
very low concentrations and meets the current standard for drinfc-
ing water quality, it can, nevertheless, leach out of plumbing
from residences and the distribution system and hence be present
at higher levels in tap water. The subcommittee could not esti-
mate the actual contribution of lead in drinking water at the tap
to health risks from lead.
Comparison of risks in ambient air and drinking water
Using the above analyses of the upper-bound estimates (assum-
ing the EPA standard of 70 years of exposure) of the annual
excess cancer incidence, we conclude that the magnitude of the
risks from the examined organics and metals in the ambient air
and from THMs in drinking water is roughly comparable—an upper-
bound estimate of 3 excess cancer cases per year. If all airborne
chromium were hexavalent, an unlikely assumption, the upper-bound
estimate for the ambient air risk would be roughly twice that of
THMs—7 excess cases per year versus 3 excess cases per year.
Table ES-4 summarizes these results.
Human health issue: Lead in the General Environment
Exposures to lead in the amb'ent air could also contribute
to the total intake of the metal from all pathways. Low levels of
lead exposure can lead to hypertension in adult males and blood-
related problems and neurological dysfunctions in children and
the unborn. However, the exposure to the levels of lead in the
ambient air of Baltimore alone are unlikely to lead to these
health problems.
ES-9
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Table ES-3
BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS
UPPER-BOUND ESTIMATES OF ANNUAL EXCESS CANCER INCIDENCE:
POLLUTANTS IN BALTIMORE DRINKING WATER1,2
PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
PHASE II RESEARCH AGENDA
Ashburton3 Montebello3
Upper-Bound Annual Upper-Bound Annual
Cancer Cases Cancer Cases
Pollutant Average — Average
(weight of Concentration 1985 Revised Concentration 1985 Revised
evidence)4 (uq/1)5 Analysis6 19867 (ug/1)5 Analysis6 19867
Chloroform8 (B2) 54.3 0.7 1.6 49.3 0.5 1.1
Total 0.7 1.6 0.5 1.1
*THE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE
UPPER-BOUND ESTIMATES. BECAUSE OF LIMITATIONS IN DATA AND METHODS IN SEVERAL AREAS OF THE ANALYSIS, SUCH AS
EXPOSURE CALCULATIONS AND POLLUTANT SELECTION, RISK ESTIMATES WERE CALCULATED AS AIDS TO POLICY DEVELOPMENT,
NOT AS PREDICTIONS OF ACTUAL CANCER RISKS IN BALTIMORE. ACTUAL RISKS MAY BE SIGNIFICANTLY LOWER; IN FACT,
THEY COULD BE ZERO. THE PROPER FUNCTION OF THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND EVALUATE
ISSUES AND SET PRIORITIES FOR THE TOPICS EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES IN THE STUDY AREA IN 1984 IS 8,000 CASES. (SEE II-8 AND
9.) THIS NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE IN UNDERSTANDING THE RISK ESTIMATES PROVIDED. IN
ADDITION, THE RISK ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING THE TOTAL UPPER-BOUND CANCER RISKS FROM
ALL POLLUTANTS IN ANY PARTICULAR MEDIUM. THEY DO NOT TAKE INTO ACCOUNT ALL POLLUTANTS THAT MAY BE PRESENT IN
THE MEDIUM, ALL SOURCES OF THESE POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING PATHWAYS OR EXPOSURES OF
SHORT DURATION TO RELATIVELY HIGH DOSES.
5Ashburton aervea a population of 900,000; Montebello serves a population of 700,000.
*EPA weight-of-evidence classification! B2 = probable carcinogen. (See Appendix A for more detail.)
^Measure of pollutant concentration in finished water over 1981-1983, City of Baltimore Drinking Water Quality
Data (Versar, 1984).
6Chloroform risk calculation based on the unit risk factor available in 1985.
7Chloroform risk calculation baaed on the moat current unit riak factor (5/7/86).
Analysis assumes total trihalonethane concentration is chloroform.
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Table ES-4
BALTIMORE IEMP PRELIMINARY RISK SCREENING RESULTS1,2
COMPARISON Of UPPER-BOUND EXCESS ANNUAL CANCER
INCIDENCE ACROSS ISSUES AND POLLUTANTS IN BALTIMORE
PHASE I RESULTS INTENDED FOR DEVELOPMENT OF THE
PHASE II RESEARCH AGENDA
(1986 analysis)
Drinking
Compound (weight of evidence)3 Air Water
Volatile Organic
Compounds
Benzene (A) 1.80
Trichloroethylene (B2) 0.02
Perchloroethylene (B2) 0.10
1,2-0ichloroethane(82) 0.10
Chloroform (82) 0.40 2.7
Carbon Tetrachloride (82) 0.30
1,2-Dichloropropane (C) 0.10
2.82 2.7
Chromium (hexavalent)* (A) 0.00 to 4.2
Cadmium5 (Bl) 0.00 to 0.04
Subtotal 0.00 to 4.24
TOTAL6 2.8 to 7.1 2.7
*THE UNIT RISK FACTORS USED IN THIS ANALYSIS ARE BASED ON
CONSERVATIVE ASSUMPTIONS THAT GENERALLY PRODUCE UPPER-BOUND
ESTIMATES. BECAUSE OF LIMITATIONS IN DATA AND METHODS IN
SEVERAL AREAS OF THE ANALYSIS, SUCH AS EXPOSURE CALCULATIONS
AND POLLUTANT SELECTION, RISK ESTIMATES WERE CALCULATED AS
AIDS TO POLICY DEVELOPMENT, NOT AS PREDICTIONS OF ACTUAL
CANCER RISKS IN BALTIMORE. ACTUAL RISKS MAY BE SIGNIFICANTLY
LOWER; IN FACT, THEY COULD BE ZERO. THE PROPER FUNCTION OF
THE ESTIMATES IS TO HELP LOCAL OFFICIALS SELECT AND EVALUATE
ISSUES AND SET PRIORITIES FOR THE TOPICS EXAMINED.
2RID'S ESTIMATE OF THE ACTUAL NUMBER OF CANCER CASES IN THE
STUDY AREA IN 1984 IS 8,000 CASES. (SEE II-8 AND 9.) THIS
NUMBER SHOULD SERVE ONLY AS A POINT OF REFERENCE IN UNDER-
STANDING THE RISK ESTIMATES PROVIDED. IN ADDITION, THE RISK
ESTIMATES SHOULD NOT BE INTERPRETED AS REPRESENTING THE TOTAL
UPPER-BOUND CANCER RISKS FROM ALL POLLUTANTS IN ANY PARTIC-
ULAR MEDIUM. THEY DO NOT TAKE INTO ACCOUNT ALL POLLUTANTS
THAT MAY BE PRESENT IN THE MEDIUM, ALL SOURCES OF THESE
POLLUTANTS, AND ALL EXPOSURE SCENARIOS INVOLVING PATHWAYS OR
EXPOSURES OF SHORT DURATION TO RELATIVELY HIGH DOSES.
^EPA weight-of-evidence classification a: A = human carcino-
gen; Bl, B2 : probable carcinogen; C = possible carcinogen.
(See Appendix A for nore detail.)
^Chromium incidence calculations indicate a range of possible
ambient levels of hexavalent chromium from 0 percent to
100 percent.
'Cadmium incidence calculations indicate a range of possible
ambient levels from 0.0 ug/m3 to detection limits (between
.001 and .002 ug/m3).
^Numbers have been rounded to one significant decimal.
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Also, lead in the first few minutes of flow of tap water can
contribute to the Baltimore area residents' overall intake of
lead; it too may put the unborn child and young children at
greater risk of adverse neurological effects and adult males at
greater risk of hypertension. Finally, ingestion of lead in
household dust is clearly a very significant threat to the health
of young children in older homes which have been painted with
lead-based paint.
Human health issue; Indoor air pollution
The subcommittee reviewed existing studies on indoor pollu-
tion. The studies, which were not specific to the Baltimore area,
suggested that indoor levels of many pollutants generally associ-
ated with the outdoors may be high enough to warrant public
health concern. In addition, the indoor environment has its own
pollutants of unique concern, such as radon and tobacco smoke.
Few data were found on actual exposure levels to indoor pollu-
tants in the Baltimore area.
Ground-water resource issue
The ranking system for determining the relative relationship
of potential threats to ground-water resources was designed to
take advantage of the expertise and professional judgment of sub-
committee members. This was necessary because of the lack of
data needed for modelling purposes or for validating models that
are or could be developed.
The ranking system takes into account both pollution impact
and economic impact. Pollution impact took into account such fac-
tors as number of sources, release volume, the present and future
rate of contamination incidents, and the potential extent of
damage. Economic impact included assessment of the relative mag-
nitude of costs to prevent or reduce contamination, and the cost
of response to contamination, again using best professional judg-
ment . Table ES-5 shows the results for the top eight source
types examined by the ground-water subcommittee.
The two issues that consistently ranked highest as potential
threats were underground storage tanks and multimedia metals
(toxic metals in the various media). They represent the sources
that are relatively the most important potential threats to
ground-water resources. The methodology does not allow us to
conclude they are problems. Chapter VI describes the analysis in
detail.
Ecological Issue; The Harbor
The harbor subcommittee examined a number of different
methods for assessing the relative significance of different
pollutants. For Phase I, they used a method, eco-scoring, which
compares ambient levels of toxics in the harbor and its tributa-
ES-10
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Table ES-5
Baltimore IEMP
Results of Relative Ranking of Sources with Potential
Adverse Inpact on Ground-water Resources1'2
Relative Ranking
Based on Equal Relative Ranking f of Times
Weighting of Based on Pollution Workgroup
Pollution Inpact and Impact Weighted as Members Scored
Economic Inpact 3 Twice Economic4 Top Five^
Underground storage Underground storage
tanks tanks 4
Multimedia metals Multimedia metals 3
Benzene Benzene 3
Pesticides/herbicides Pesticides/herbicides 2
Pollution from farming Pollution from farming 1
Landfills Landfills 1
Septic Tanks Septic Tanks 1
Chromium in Harbor Chromium in Harbor 1
1Based on a system developed by the ground-water workgroup, Which ranks
sources for potential for damage to ground-water resources. These rankings
are for the purpose of setting priorities for further study; they do not
apply to specific sites within the study area, but rather, provide results
of the workgroups1 deliberations regarding the relative ranking of potential
threats to the ground-water resource.
2Qnly the top eight sources are shown; the other five sources can be found in
Chapter VI.
^The first scoring system used by the ground-water subcommittee weighted pol-
lution inpact and economic impact equally.
4"The ground-water subcommittee changed the scoring system slightly, weighting
pollution impact twice as heavily as economic inpact, to determine how sensi-
tive the scoring system was to variation.
^This counts the number of times the source scored in a ground-water workgroup
member's top five sources. As there were 4 members in the workgroup, the top
score was 4.
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riea to EPA'a Water Quality Criteria.
For metal* in the ambient water, mercury* lead, nickel, and
copper scored high, though lead was of concern only in an older
set of data. Mercury was the metal of greatest concern in the
tributaries. In the sediments, chromium had a higher score than
the other metals. In comparing the metals in the Harbor with
those in the Bay, all metals were higher in the Harbor than the
Bay with the exception of copper. These metals represent the
relatively most important potential threats to the Harbor. The
methodology does not allow us to conclude they are problems. The
indexing results are summarized in Table ES-6. Chapter VII de-
scribes the analysis in detail.
CONCLUSIONS ABOUT THE PROJECT TO DATE
The EPA, Maryland State government, and local government
officials have established the organizational framework at the
State and local level for setting priorities for government
action on environmental issues in the study area. The Management
Committee MC, with the assistance of the Technical Advisory Com-
mittee (TAG) effectively identified and set priorities among a
wide-ranging and diverse set of environmental issues.
The Baltimore IEMP has helped State and local governments
develop a working understanding of methods for analyzing issues.
Priority-setting in the Baltimore IEMP was a hands-on process.
The TAG played an active role through its provision of expert
judgment while it used analytical tools to identify important
environmental issues and compare and rank them against evaluative
criteria. The success of representatives of State and local
jurisdictions in reaching consensus on questions of environmental
priorities that unevenly affect them testifies to the usefulness
of these tools and these governments' ability to use them. Also,
EPA held workshops for both government officials and the general
public to familiarize them with the use of risk assessment.
The Baltimore IEMP has helped State and local governments
address a high-priority problem. The State and counties drasti-
cally reduced the standards for the amount of lead used in solder
and flux in the plumbing of residential drinking water systems
after work during Phase I identified this as a potentially seri-
ous health problem. However, most of the tangible progress to-
wards solving other environmental problems is generally not ex-
pected until completion of the second phase of the project.
ES-11
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TABLE ES-6
Baltimore IEMP
Comparison of Index Values For Harbor Priority-Setting,
Using Different Types of Indexing Techniques ^
Ambient Water Quality
Harbor
Trident IEMD
Data1 Data2
Ambient Water
Quali ty-Tributaries
Ambient Sediment Ambient Sediment
Quality-Baltimore Quality-Chesapeake
Harbor Bay
Zinc
Nickel
Mercury
Lead
Copper
Chromium
Cadmium
e e
+ 4-
O O
+
O 4-
• *
0 •
+
N/A
O
0
O
+
N/A
+
+
N/A
O
O
O
N/A
N/A
+
N/A
N/A
N/A
+
N/A
O Index value greater than 2.
Criteria)
4- Index value greater than 1.
* Index values less than 1.
N/A Not Available.
(Ambient values are more than twice the level of EPA
(Ambient values are greater than EPA criteria)
(Ambient values are less than EPA criteria).
1. See Figures VI1-6 to VII-10 for a presentation of the indexing scores and the
sources of data used to generate this table.
2. Assumed undetected monitoring values were equal to half the detection limit.
figure VII-7 and p. 14 for further explanation.
See
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The Baltimore IEMP has provided information that will help
EPA conduct its programs. EPA has lacked analytical methods and
procedures for setting priorities among issues that do not direct-
ly relate to health. In Phase I of the Baltimore IEMP, we have,
made progress in developing priority-setting tools for ecologi-
cal issues relating to the aquatic environment and a procedure
for achieving consensus on issues of importance to ground-water
resources.
PHASE II STUDIES
We present below a brief summary of the five issues selected
for Phase II study. The order of presentation does not reflect
their relative importance. Importantly, each study area is tai-
lored to Baltimore's needs and with the recognition that local,
state and EPA regional staff are also working in these areas.
In effect, our work fits into the overall area environmental
agenda to maximize what all levels of the governments are learn-
ing about issues in Baltimore.
Air Toxics
Air toxics were found to be a potentially significant though
undefined threat to public health in the Baltimore area. The
State air toxics program is being designed to address area-wide
problems from industrial emissions of air toxics. To complement
this effort, the IEMP air toxics study is designed to address the
so-called "urban soup" where toxic emissions from both point and
area sources combine to form elevated concentrations of pollutants
in localized areas. The goals are to estimate human health risk
from selected air toxic emissions from both industrial and area
sources and to analyze control strategies to reduce the adverse
health effects.
An important part of this effort is the Baltimore Total
Exposure Assessment Methodology (TEAM) study to be conducted in
conjunction with EPA's Office of Research and Development. This
study will help provide information on the relative risks of in-
door versus outdoor pollution. The objectives of the study are:
- to apply "modified" TEAM methodology to Baltimore to
estimated exposure of Baltimore area residents of specific
geographic areas to selected volatile organic compounds;
- to compare modeled concentrations with measured ambient
levels for selected volatile organic compounds.
- to compare indoor concentrations, outdoor concentrations,
and personal exposures.
ES-12
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Multimedia Metals
The MC and the TAG found metals from a wide variety of
sources and in all media to pose potentially significant health
and environmental risks. The Phase II will focus our limited
resources on one major issue and allow the IEMP the best chance
of assisting local officials in managing it.
The major task is to develop cost-effective techniques for
removal and abatement of lead paint and dust. An extensive num-
ber of studies dealing with various aspects of exposure to lead
indicate that current techniques for abating lead paint and. dust
are not very effective and, in some cases, actually increase the
levels of lead dust in housing.
Indoor Air Pollution
While data from other cities suggest that indoor pollution
may pose significant risk to human health, there is little local
data on whether indoor pollution is also a problem in the Balti-
more area.
The goals of the workplan are to learn more about indoor air
quality in Baltimore; to investigate possible programs to reduce
exposure from indoor air pollution;' and to recommend their imple-
mentation where appropriate.
Underground Storage Tanks
The TAG and the MC chose leaking underground storage tanks
(USTs) as an issue to be studied in Phase II because USTs were
highly ranked relative to other potential sources by the ranking
system used to assess potential damage to ground-water resources.
Because Maryland already has regulated underground storage tanks,
the UST workgroup members perceived a unique opportunity to
develop a study which would help the state and local government.
The analysis focuses on developing an approach to help establish
priorities for inspection and enforcement activities, given the
governments' limited resources.
Baltimore Harbor
The TAG and the MC chose Baltimore harbor as an issue for
Phase II because of the importance that pollution of the harbor
can have on the current and future uses of this vital resource.
Our objectives are to define the possible future uses of the har-
bor and to identify additional research and institutional arrange-
ments that should occur to help environmental decision-makers
understand how to achieve any set of goals they have to ensure
that those uses can occur. The work group will also explore
methods to assess the effects of pollutants on aquatic life.
ES-13
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