EPA/600/N-93/014
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Region II, New York, New York 10278
DATE:
SUBJECT:
FROM:
August 19, 1993
Risk Assessmnt Review
William J . J
Deputy Regional Administrator
William Farland,
Director
Office of Health and Environmental Assessment
Attached is a copy of the Ri$k Assessment Review, a bimonthly
publication that is a cooperative effort between the Office
of Research and Development and the Regional Risk Assessment
Network.
The Review serves as a focal point for information exchange
among the EPA risk assessment community on both technical and
policy issues related to' risk assessment. It is currently in
its fourth year of publication and we are pleased at the
positive feedback we've received on the Review's usefulness
to staff across the Agency.
Thanks to all of you who continue to contribute articles and
are involved with production efforts. If you have an article
to contribute or any suggestions for further issues, contact
one of the Committee members listed on page 1 of the Review.
Attachment
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Risk Assessment Review
Highlights
• Federal-State Toxicology and
Risk Analysis Committee (FSTRAC) p. 1
Exposure Models Library and IMES on CD-ROM p. 1
Risk Assessment Library on CD-ROM p. 9
• IRIS Highlights p. 9
I. Special Feature
Federal-State Toxicology and Risk Analysis
Committee (FSTRAC) Water Issues in the
Northeast
By Bob Cantilli, 202-260-5546
Ed Ohanian, 202-260-7571
Introduction
A total of 41 representatives from 11 states, pne EPA
region, and EPA headquarters gathered at the spring Fed-
eral-State Toxicology and Risk Analysis Committee
(FSTRAC) meeting in Albany, NY. After an update on
EPA drinking and ambient water regulations and criteria,
representatives from northeastern states discussed current
drinking and ambient water issues in their states. FSTRAC
subcommittees met to review accomplishments over the
past six months and to plan for the next six months. Every-
July 1993
Risk Assessment Review Committee
Bill Farland - ORD, 202-260-7317
Maureen McClelland - Region 1,617-565-4885
Maria Pavlova - Region II, 212-264-7364
Marian Olsen - Region n, 212-264-5682
Suzanne Wuerthele - Region VIII, 303-293-1714
Dana Davoli - Region X, 206-553-2135
one took pan in a participatory exercise to address a case of
methyl t-butyl ether contamination in a fictitious town.
Finally, the group discussed several hot issues, including
leaking underground storage tanks, a study of polychlori-
nated-biphenyl (PCB) exposure via fish in the Mohawk
population in New York state, arsenic in private wells, and
the potential for drinking water contamination due to PCBs
and nonfood-grade oil in submersible well pumps.
This article summarizes the presentations by state represen-
tatives, as well as the hot issues discussion.
(see FSTRAC p. 2)
II. Headquarters
Exposure Models Library and IMES on CD-
ROM
by Rich Walentowicz, 202-260-8922
The Office of Health and Environmental Assessment
(OHEA), U.S. Environmental Protection Agency (EPA),
has developed the Exposure Models Library and Integrated
Model Evaluation System (IMES) Compact Disk-Read Only
Memory (CD-ROM) to demonstrate the use of media and
technology for distributing exposure models, documenta-
tion, and a model selection system for use in exposure and
risk assessment.
The Exposure Models Library presents about 70 exposure
models for determining fate and transport in various envi-
ronmental media. The models were developed primarily by
various EPA offices and other federal agencies and are in
the public domain. IMES is a PC-based application devel-
oped for exposure and risk assessors as well as other users
interested in fate models. It assists users in the selection of
appropriate fate models from the users' response to query of
site characteristics and model capabilities. IMES is the
result of the integration of several projects addressing expo-
sure and fate models. ,
OHEA has completed a number of enhancements to IMES.
The Exposure Models Library and IMES disk now contains
the complete source codes of the models along with sample
input and output files. An interface was developed for easy
access to IMES and the model directories. This interface
also indicates the amount of space required for download-
ing any of the model files and allows for viewing of the text
files. Where documentation was available, it was included
in separate subdirectories to the models.
The selection module is the principal focus of the system. It
assists a user in the selection of appropriate fate models
from the user's response to questions on site characteristics
or a scenario of interest
The validation module retrieves background information on
models and their validation status, (see CD-ROM p. 9)
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FSTRAC (continued from p. 1)
Overview of the New York State Drinking Water
Program
The Director of the Bureau of Public Water Supply Protec-
tion, New York State Department of Health (DOH), gave an
overview of the New York State Public Drinking Water
Regulatory Program. The mission of the program is to
assure the safety of public drinking water in New York by
ensuring that water suppliers comply with drinking stan-
dards, local health departments adequately implement pro-
gram elements, water suppliers adequately protect their
supplies and plan for future needs, potable drinking water is
provided during emergencies, regulatory and water supply
professionals are technically competent and current, and the
program is effectively administered.
The state, which has primacy, currently regulates 11,000
public water systems (PWSs), of which 3,400 are commu-
nity water systems and 750 are nontransient noncommunity
water systems. The state regulatory program is implemented
by county health departments, except for some rural areas
that the state oversees because no county program exists.
County health departments are in charge of day-to-day
inspections of treatment facilities and enforcement of the
program.
Overview of New York State Ambient Water
Quality Program
The Director of the Bureau of Water Quality Management,
New York State Department of Environmental Conserva-
tion (DEC), gave an overview of the New York State
Ambient Water Quality Program. New York State is rich in
ambient water resources, containing more than 50,000 miles
of streams, 1,100 square miles of lakes (Lakes Erie and
Ontario cover 4,200 square miles), and 120 miles of coast-
line. With no prior comprehensive listing of the problems in
these water resources, the state developed a Priority Water
Problems (PWP) list that outlines waters with impaired uses
with regard to drinking, swimming, fishing, fish propaga-
tion, and shell fishing.
The. first step in developing the PWP list involved obtaining
public input on water quality issues. Local agencies were
encouraged to reach out to the public to discover suspected
water quality problems. The second step was to verify
known or perceived water quality problems. The third stage
involved a consensus evaluation of potential PWP listings
by regional fisheries, the county authorities, and an arbitra-
tor. To facilitate this process, impaired segment data sheets
were prepared. These data sheets summarize available wa-
ter quality data, including type, degree, and extent of im-
pairment; pollutant type and source; resource value and
class; and flow data. County water quality committees have
used the impairment data to develop water quality guidance
for both point and nonpoint sources. The information base
is raised awareness that nonpoint source problems are
more significant in New York than point sources. In addi-
tion, sediment contamination has been identified as a major
problem in the state's water resources.
New York State is undertaking a major new policy initiative
called the Water Quality Enhancement and Protection
(WQEP) Policy. The specific goals of the WQEP Policy are
to protect sensitive waters, maintain high-quality waters,
and protect waters from persistent toxics. The policy covers
Discharge Restriction Categories (DRCs), substance bans,
antidegradation of water resources, and encourages public
participation in all phases of enforcement of the policy. The
purpose of DRCs is to enhance and protect New York's
waters by restricting or prohibiting discharges of certain
substances (e.g., phosphorus) into special waters. The pur-
pose of the substance ban is to enhance and protect present
water quality by banning specific persistent toxic sub-
stances. Finally, the purpose of the WQEP policy's
antidegradation element is to protect New York's waters
from actions that could degrade water quality that is cur-
rently above standards.
Phase V Drinking Water Standards: Implementa-
tion in New York State in Light of the New York
State General Organic Standards
The Chief of the Toxicological Assessment Section of the
Bureau of Toxic Substance Assessment, at the New York
State DOH, discussed EPA Phase V drinking water stan-
dards in light of New York's general organic standards.
In 1988, New York adopted a comprehensive approach to
regulating the concentration of organic chemical contami-
nants in drinking water which uses both contaminant-spe-
cific and general maximum contaminant levels (MCLs).
The approach categorizes all organic contaminants, with
few exceptions, into two broad groups, principal organic
chemicals (POCs) and unspecified organic chemicals
(UOCs). An MCL of 0.005 mg/L was established for the
POCs and applies to any contaminant in the following
classes: halogenated alkanes; halogenated ethers; haloben-
zenes and substituted halobenzenes; benzene and alkyl- or
nitrogen-substituted benzenes; substituted, unsaturated hy-
drocarbons; and halogenated nonaromatic cyclic hydrocar-
bons. This group excludes trihalomethanes and any other
organic contaminant with a specific New York State MCL.
An MCL of 0.05 mg/L was established for UOCs and
applies to organic chemicals in other than the principal
classes which are not covered by another New York State
MCL. An MCL of 0.1 mg/L was established for total POCs
and UOCs.
New York regulations contain provisions for establishing a
higher MCL than the general MCL for any specific organic
contaminant However, the general MCLs for organic con-
taminants apply unless valid scientific data shows that the
chemical does not pose an unreasonable risk to human
health, the chemical is present at a level and under circum-
stances not indicative of contamination, and the cost of
compliance is unreasonable in light of the degree of risk to
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human health. Implementation of Phase V standards in New
York must consider the general MCLs and the criteria upon
which they are based. Assessment of the adequacy of the
lexicological data base is an important aspect of New
York's review process. The speaker briefly summarized the
findings of New York's technical review of the toxicologi-
cal data base for eight organic contaminants which cur-
rently have lower New York State general MCLs than the
equivalent Phase V EPA MCLs. Inadequacies in the loxico-
logical data base for these eight organic contaminants ap-
pear sufficient to support maintaining the lower MCLs in
New York. The speaker emphasized, however, that the
other risk management factors had to be considered before
any final decisions are made on the implementation of
Phase V MCLs in New York.
An attendee asked if using a generic approach to regulate
organic contaminants had proved advantageous for the state.
New York's comprehensive approach to regulating the
concentration of organic contaminants establishes enforce-
able MCLs which reflect a balanced consideration of rel-
evant risk management factors in the regulatory process. In
the absence of an adequate lexicological data base, it pro-
vides a reasonably achievable degree of protection and is
consistent with a preveniative public health policy.
Comparison of Human Health Methodologies:
EPA, Great Lakes Guidance, and New York State
The New York State DEC has methods in regulation for
deriving ambient water quality standards and guidance val-
ues to protect human health; EPA published methodologies
for deriving Clean Water Act (CWA) ambient criteria in
1980, which are currently undergoing revisions; and, on
April 16,1993, EPA proposed water quality regulations for
ihe Great Lakes System entitled Great Lakes Guidance
(GLG). A representative from DEC compared the New
York, EPA, and GLG methodologies for human health.
A potential revision to EPA guidance and the GLG is the
use of tiered criteria for data. New York does not use tiered
criteria. EPA, however, is considering five tiers of criteria
for the CWA methodologies, depending on the amount and
quality of the data. Tier II data, for example, are the
minimum required for a Reference Dose (RfD) or to quan-
tify cancer risk, and Tier III data are restricted to use for
interim permit values. The GLG has two-tiered criteria:
Tier I for extensively studied contaminants which allow
ambient water criteria development, and Tier II for less
well-studied contaminants that are only enough to set per-
mit limits.
The minimum data required lo regulate noncarcinogens are
not specified in New York (professional judgement used),
EPA could require a 90-day study (28-day acceptable in
exceptional cases), and the GLG requires 90-day and 28-
day studies under Tier I and Tier II, respectively. The
minimum cancer data requirements in New York are tests in
one species of mammal with supporting data; EPA includes
Group A, B, and some Group C compounds in Tier II, and
some Group C compounds are included in Tier HI. GLG
includes Group A, B, and some possible human carcino-
gens under Tier I and only some Group C compounds under
Tier II.
For cancer risk assessment, the risk level used in New York
is 10-*, whereas EPA employs a range, and GLG proposes a
risk level of 10"3. The interspecies conversion factor used in
New York is body weight to the 2/3 power (surface area
conversion); EPA may use a revised factor of body weight
to ihe 3/4 power, and, GLG currently proposes body weight
to ihe 2/3 power. New York defines substances as oncogens
without reference to EPA classification. EPA, under its
drinking water program, is currently applying an additional
uncertainty factor to noncancer endpoints for Group C
chemicals to account for potential carcinogenicity; GLG
recommends quantitative risk assessment for some possible
human carcinogens.
In regard to exposure assumptions for drinking water and
fish consumption, New York develops separate water qual-
ity values, EPA is leaning toward separate water quality
values, and GLG proposes water quality values for com-
bined exposure. For drinking water consumption New
York uses 2 liters (L)/day; EPA uses 2 L/day but may
consider L/kilogram (kg) body weight; GLG also
uses 2 L/day. New York does not consider incidental
exposure; EPA does only when deemed necessary; and
GLG uses a value of 0.01 L/day. For fish consumption,
New York uses a fish lipid intake value of 1 gram (g) lipid/
day (33 g fish/day x 3 percent fish lipid content), EPA
advocates presenting a range with the final risk assessment
but is attempting to derive a g/kg body weight (bw)
assumption, and GLG uses a value of 0.75 g lipid/day (15-
g fish/day x 5 percent fish lipid content). Finally, for
human body weight. New York uses 70 kg for an adult and
10 kg for a child, EPA uses 70, 10 kg defaults and is
moving to a per kg bw basis, and GLG assumes 70 kg.
Breath Analysis and Physiologically Based Phar-
macokinetic Modeling to Assess Exposure to
Contamination in Drinking Water
The Chief of the Exposure Assessment Section of the
Bureau of Toxic Substance Assessment at the New York
DOH described a project to estimate exposure via inhala-
tion and dermal contact to Volatile Organic Contaminants
(VOCs) while showering. The state used breath analysis as
a means of monitoring actual exposure, while a physiologi-
cally based pharmacokinetic (PBPK) model incorporated
information from breath analysis to predict actual doses.
PBPK modeling traces the storage and release pathways for
the contaminant in and from the organs that hold the con-
taminant. A mass balance approach allows the model to
account for all of the dose in each tissue, using data regard-
ing blood flow and air ventilation rates, tissue volumes, and
metabolic rates. Several models have been validated for
animals, as well as some parameters for humans.
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Research at a medical/dentistry university in New Jersey
showed a fairly linear relationship between water concen-
tration of chloroform and air concentration in the shower:
60 percent of the contaminant volatilized (and was therefore
available for inhalation), while 40 percent remained in the
water (available for dermal contact). The researchers com-
pared breath samples from human volunteers who took a
normal shower and from those who took a shower with
complete skin protection. With both types of shower, mea-
sured breath concentrations of chloroform increased lin-
early with water concentrations. The ratio between the
alveolar air and blood concentration (blood/air partitioning
coefficient) and the dermal absorption ratio were used in the
PBPK model. The PBPK model quantified the blood con-
centrations and flow through slowly and rapidly perfused
organs, fat, and the liver, as well as interaction between the
alveolar space (lungs) and blood, and the stratum corneum
(skin) and viable skin. The partitioning coefficients were
used to predict the inputs to the organ system via lung and
skin.
Using the model, the researchers predicted the amount of
chloroform that would be absorbed during showering and
the concentration in breath during and after showering.
Inhalation alone does not account for all the absorbed dose:
at 20 micrograms (ng)/L chloroform concentration in wa-
ter, the dermal absorbed dose is nearly equal to inhalation
absorbed dose. Both are about one-tenth the absorbed dose
from drinking the same water. The total risk from all
exposures is 5 x 10"*; the risk from inhalation and dermal
exposure is 5 x 10"7.
Trends in Volatile Organic Chemical (VOC)
Contamination Over Time; New Jersey's Potable
Water Research Program
The Assistant Director of the Division of Science and
Research at the New Jersey Department of Environmental
Protection and Energy (DEPE) discussed trends in synthetic
organics occurrence in delivered water over time and New
Jersey's drinking water research program.
New Jersey has the longest running program for monitoring
synthetic organics in drinking water, the result of 1984
amendments to the New Jersey Safe Drinking Water Act
(SDWA), which require periodic monitoring of delivered
drinking water and the development of MCLs for 22 spe-
cific analytes. New Jersey is currently monitoring drinking
water samples for 17 of these 22 analytes. Standardized
analytical methods are not available for the detection of
other listed analytes. From 1984 to 1990, in 13 semiannual
sampling rounds, 635 community PWSs were monitored at
the tap to obtain a profile of detectable contaminants in
drinking water. More than 10,000 samples have been col-
lected to date, making this data base one of the country's
largest on VOCs. Water quality improvements have been
observed over time as a result of the regulatory program.
The percentage of PWSs reporting detectable levels of
hazardous constituents greater than the MCL has fallen
since sampling began. The percentage of purveyors detect-
ing contaminants greater than the regulated MCL decreased
from 15 percent in 1984 to 4 percent in 1992.
Two research projects conducted under New Jersey's drink-
ing water research program were also discussed. The first
project examined the effect of flushing on lead levels in
school drinking water. The objectives of this study were to
determine the effectiveness of flushing and to evaluate the
relationship of lead concentration to water source, plumb-
ing, the age of the school building, and corrosivity.
The results of the study indicate that one-time flushing of
fountains may not provide day-long protection from lead
contamination in school buildings. The study also indicated
that school buildings constructed after the lead solder ban
might still contain sources of lead in plumbing. Lead solder
tests in these buildings show that, despite the ban, lead
solder is still being used in some cases. In addition, the
study found that correlations existed between corrosivity
and lead levels; lead levels in corrosive water were signifi-
cantly higher than in noncorrosive water. This study has
produced policy implications for water monitoring in schools
in New Jersey and for flushing as a means of reducing lead.
The Bureau of Safe Drinking Water now recommends
monitoring after flushing in addition to first-draw sampling.
In addition to one morning-period flushing, the Bureau of
Safe Drinking Water now recommends schools with el-
evated lead levels flush fountains every 2 to 3 hours.
The second research project was initiated as a result of
reports of mercury contamination in many wells in one
major drinking water aquifer system (Kirkwood-Cohansey)
in southern New Jersey. Mercury at levels greater than tlw/2
(ig/L MCL has been detected in many wells in this system.
Background mercury levels in this aquifer are generally 1 to
10 ng/L (ppt). The objectives of this project were to validate
the reported contamination detected by using more specific
sensitive analytical techniques than the standard EPA meth-
odology to determine background levels of mercury in
southern New Jersey ground water and to determine the
mercury species present in water samples for the purposes
of risk assessment
The results of this study were as follows:
• A mercury contamination problem was confirmed in
southern New Jersey ground water. EPA methodology
is adequate for screening contaminated wells but less
reliable for determining mercury concentrations below
2 ng/L.
• Background median mercury levels were determined
to be less than 1 to 10 ng/L (ppt).
Inorganic mercury (mercuric chloride) was the pre-
dominant species. Elemental mercury in contaminated
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wells accounted for up to 10 percent of total mercury in
the sample and methyl mercury, up to 8 percent of total
mercury.
Risk assessments conducted using these speciation data
indicate that the maximum estimated potential concentra-
tion of elemental mercury in the shower compartment is 10
M.g/cubic meter (m3), based on the maximum concentration
in water of 0.4 |j.g/L and 100 percent volatilization. This
level is higher than EPA's Reference Concentration (RfC)
of 0.3 ng/m3. The study also indicates that the maximum
acceptable concentration of methyl mercury in drinking
water via ingestion is 0.2 M-g/U compared to EPA's RfD of
0.3 mg/kg/day. New Jersey has detected methyl mercury in
drinking water at levels up to 0.14 |ig/L.
An Alternative to the Total Petroleum Hydrocar-
bon (TPH) Parameter
A representative from the Massachusetts Department of
Environmental Protection (DEP) discussed the develop-
ment of a health-based alternative to the total petroleum
hydrocarbon (TPH) parameter. Petroleum is a major con-
cern in Massachusetts because it is the significant contami-
nant at 60 percent of the state's hazardous waste sites. No
uniform way currently exists to address petroleum contami-
nation. The goal of the alternate approach is to develop a
method of quantitatively addressing the hydrocarbon frac-
tion of petroleum.
The ideal approach for a health-based assessment is to
quantitate all petroleum hydrocarbons individually, develop
toxicity values for each compound, quantitate TPH, and use
whole-product toxicity values. This approach is currently
unrealistic. An alternative approach was required to identify
dose-response values for specific ranges of petroleum hy-
drocarbons and to develop analytical methods that quantify
specific ranges of petroleum hydrocarbons. Toxicity data
were identified by searching EPA's Integrated Risk Infor-
mation System (IRIS) and the Office of Solid Waste and
Emergency Response (OSWER) Health Effects Assess-
ment Summary Tables (HEAST) data bases, the American
Petroleum Institute's data base, National Technical Infor-
mation System (NTIS), Toxline, Toxnet, and various Euro-
pean data bases. In summary, there was a lot of information
on acute data, a modest amount on whole-product data that
was not applicable to the weathered product, and little data
for chronic effects. EPA data were used to develop the
health-based alternative.
Various analytical methods were evaluated by DEP for
TPH analysis, including gravimetric techniques, infrared
and ultraviolet spectrometry, gas chromatography, and tech-
niques for gas chromatography/mass spectrometry. Due to
the limitations of these methods, analytical schemes were
developed to measure extractable petroleum hydrocarbons
and volatile petroleum hydrocarbons by GC, FID, and PID
in series. Using the proposed approach to analyze TPH and
applying the results to determine exposure to alkanes and
alkenes via soil, DEP derived alternative RfDs of 0.06,0.6,
and 6 mg/kg/day for compounds of 5 to 8,9 to 18, and 18 to
32 carbons, respectively.
In summary, characteristics of the TPH alternative include
the following:
• It is based on a range of compounds.
• Its dose-response values are specific to each range of
compounds.
It better defines TPH.
It discerns differences in toxicity of TPH.
It yields more information that can be used in human
health risk assessment
Reconciling Science with Legislative Require-
ments: State Perspectives on the Safe Drinking
Water Act
The Deputy Director of the Water and Air Toxics Office of
Research and Development at the Massachusetts DEP dis-
cussed reconciling science and policy in setting federal
drinking water standards and highlighted the states' per-
spectives. A number of individuals from several states
prepared a report summarizing states' views regarding the
reauthorization of the SDWA. The report includes sugges-
tions on how the SDWA could be modified to use resources
more fruitfully.
The first issue discussed was the effect of statutory dead-
lines and regulatory actions under the 1986 SDWA amend-
ments on the number of contaminants regulated. Prior to the
1986 amendments, there were 21 contaminants with na-
tional primary drinking water regulations (NPDWRs); by
1991, SO contaminants had actual final MCLs and more
than 100 had statutory requirements. Slates question the
utility of the schedule for new standards because EPA
hasn't been able to meet the schedule for new standards to
date.
Issues to be resolved in the generation of NPDWRs include
the under-addressed chemical groups, such as the polar
organics, and the shift in occurrence of data-gathering
efforts for unregulated chemicals from nationwide surveys
to reports from the state or purveyor. This latter issue raises
many concerns. Alternative approaches suggested for gen-
erating NPDWRs include using an occurrence frequency
cutoff or concentration cutoff for regulation of specific
chemicals. The indirect impacts of the generation of
NPDWRs on private wells were also outlined. These im-
pacts should be considered in a regulatory agenda, as should
the financial capabilities of small PWSs to meet the costs of
requirements. These issues raise the question of whether the
goal of generating NPDWRs has shifted from reducing the
number of significant health risks to increasing the number
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of chemicals regulated. States would prefer to use guidance
for more rare chemicals on a state-by-state basis, rather than
enforce national monitoring and compliance standards.
In summary, a change in the standard-setting schedule was
recommended, and recognition of region-specific needs
was advocated. For naturally occurring chemicals (e.g.,
arsenic), it was recommended to set health-based guidelines
and to allow states to apply region-specific criteria to en-
force such standards. Other routes of exposure should also
be recognized when setting drinking water standards.
Proposed Use of Herbicides Against Milfoil in
Vermont Lakes: Potential Impact on Drinking
Water
Attempts to identify control alternatives for Eurasian
watermilfoil were described by the Chief of the Toxicology
and Risk Assessment Program at the Vermont Department
of Health (DOH). Milfoil is a prolific aquatic weed, which
in 1991 affected 35 lakes in the state. Under state law,
however, no chemical can be added to water supplies until
none hem ical alternatives have been evaluated. No reason-
able nonchemical alternatives were identified (out of a list
ranging from handpulling and hydroraking to the introduc-
tion of grass carp and milfoil-specific fungus). In accor-
dance with the law, DOH is now evaluating several pesticides
for adverse effects on humans and wildlife, examining the
social benefits to the public in using the pesticides to
control the milfoil, and developing a long-range lake-mil-
foil management plan.
In an informal survey of state environmental commissions,
Vermont discovered that few herbicides have been used
near or in potable water (all of Vermont's lakes are classi-
fied for drinking water). The three chemical control alterna-
tives are 2,4-D, fluoridone (Sonar), and tricopyr (Garion
3A). 2,4-D will not be used because of health concerns and
attempts by the Vermont Public Interest Group to obtain a
ban on its use in the state. Fluoridone must be used on the
entire lake, and there is some outcry from environmental
groups concerning N-methylformamide, a potential break-
down product. Triclopyr, the most promising of the com-
pounds, is available for experimental use only, so it will be
tested in a badly affected lake. The residents around the test
lake have been notified of the test and have been directed
not to swim in the lake for one day after application.
Regulating Leaking Underground Storage Tanks
in North Carolina
A FSTRAC member from the Environmental Epidemiol-
ogy Section of the North Carolina Department of Environ-
ment, Health, and Natural Resources (DEHNR) described
efforts to regulate leaking underground storage tanks
(LUSTs). In North Carolina, more than 55 percent of the
population uses private drinking water wells. About 10
percent of the total number of underground storage tanks in
the state (5,000 tanks) are leaking, affecting 800 drinking
water wells. The North Carolina LUST law directs DEHNR
to regulate tank design and construction, performance stan-
dards, etc. If the responsible party cannot be found, federal
and state funds can be used for cleanup and alternative
water supplies for affected households. Cleanup levels are
the state ground water standards.
In a typical LUST situation, the state's health department
receives a complaint from a resident. The health department
then contacts the environmental epidemiology section at
DEHNR for a risk evaluation. The resident, health depart-
ment, and Department of Environmental Management
(DEM) are notified of the results, and DEM visits the site to
determine the extent of any plume and the concentrations of
the plume components in the drinking water. After a site-
specific risk assessment, DEM can proceed with a cleanup.
To date, the primary contaminants found are toluene, xy-
lene, methylated benzenes, and diisopropyl ether. The stan-
dard for diisopropyl ether is based on taste and odor
thresholds because little lexicological data are available.
Methyl t-butyl ether is detected at the leading edges of the
plume and appears in the drinking water first in most
instances. 1,2-dichloroethane and 1,2-dichloropropane are
often found further away from the plume, even detached
from it. Ethylene dibromide has not been observed as often
but is associated with leaded gasoline leaks. Finally, ben-
zene, the driving force behind the regulation of LUSTs, is
probably the primary ground water problem in the state in
terms of severity. When contamination is found in well
water, the state recommends actions based on the levels
found. If the levels are close to the standards for the
contaminants, a second sample is taken. If the level is found
to be over or up to ten times the standard, the residents are
directed to use alternative drinking water. If higher than ten
times the standard, the residents also are asked to reduce
shower times. If higher than 40 times the standard, no water
use for any purpose would be recommended.
Range Expansion of the Zebra Mussel and Poten-
tial Impact on Surface Water Supplies of Drink-
ing Water
A representative from the New York Sea Grant discussed
the rapid range expansion of the zebra mussel throughout
the Great Lakes and numerous inland river systems in North
America, the impacts of the mussel on surface drinking
water supplies, and control alternatives which might be
implemented to limit these effects.
The zebra mussel is a small (2 to 3 cm in length) bivalve
mollusk with elongated shells typically marked by alternat-
ing light and dark bands. Zebra mussels secrete durable
elastic strands (byssal fibers) by which they can securely
attach to nearly any surface, forming barnacle-like encrus-
tations. The zebra mussel is believed to have been carried to
North America in 1986 in the freshwater ballast of ships
originating from overseas freshwater ports where the mus-
sel is found. The zebra mussel was first discovered in the
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Great Lakes Basin in Lake St. Clair in June 1988. Natural
dispersal mechanisms have helped the zebra mussel expand
its range from the Great Lakes east to New York, south to
Louisiana, and as far west as Oklahoma.
A major impact of the zebra mussel is the fouling of raw
water intakes such as those at drinking water facilities.
Exclusion, removal, and avoidance control alternatives for
the zebra mussel include the following:
• Preventing entry of the mussel into water systems
using filtration methods such as buried intakes, sand
filtration systems, and strainer systems including fixed
strainers, cyclone separators, and centrifugal filters.
• Maintaining intake and distribution flows to prevent
the settling of mussels.
• Physically scraping mussels from water systems.
• Pigging for systems with small diameter pipes, with no
large scale access, and which cannot easily be taken off
line.
• Depriving mussels of oxygen by hermetically sealing
intakes or isolated service areas.
• Destroying them thermally. Generally the higher the
temperature the sooner the mussels die.
Desiccating mussels, which works best at high tem-
peratures and high humidities.
• Treating the mussels chemically to induce toxic effects
on mussels or to oxidize the mussel's organic material.
The chemicals that are most toxic to the mussels are
dichloro-2'nitro-4'salicylanilide, and N-triphenyl-
methylmorpholine.
• Oxidizing the mussels with biocides, such as chlorine,
chlorine dioxide, ozone, potassium permanganate, hy-
drogen peroxide, and chloramine.
Applying antifouling coatings to prevent attachment of
zebra mussels to surfaces.
• Using high-tech avoidance alternatives such as ultra-
violet beta radiation and high-energy acoustic sound
waves.
• Implementing biological control alternatives. Research
is currently underway to investigate these control op-
tions.
• Training boat owners. If boats have been in infected
waters for a day or two, their hulls should be inspected
when tbjy are on trailers, engine water should be
drained, oilge water emptied, bait buckets drained, and
the boat should be hosed off. If boats have been in
infected waters for a week or more, they should be
washed in a carwash and dried in the sun for a few
days.
Hot Issues
Representatives from EPA and the states identified and
presented the following current "hot" issues:
Water Quality Standards for Methyl t-Butyl
Ether
Representatives from New Jersey DEPE and New York
State DOH gave two perspectives on setting water quality
standards for methyl t-butyl ether (MTBE).
The New Jersey representative pointed out that MTBE will
become more of a problem as EPA's oxygenated fuel
program comes into effect. New Jersey has developed a
proposed health-based maximum contaminant level based
on a 90-day gavage study. New Jersey's proposed health-
based MCL is 0.7 mg/L. The New Jersey value uses a
modifying factor of 3 for lack of data on reproductive and
developmental effects. New Jersey is delaying making its
proposed level final until EPA completes its evaluation.
In New York State all organic chemicals which do not have
a compound specific organic drinking water standard have a
generic drinking water standard and are regulated as princi-
pal organic contaminants (POCs) or unspecified organic
contaminants (UOCs). MTBE is regulated as a UOC and
has a drinking water standard of SO u,g/L. New York State is
currently preparing a risk assessment for MTBE and re-
viewing new data, including the recent carcinogenicity
studies which show hepatocarcinoma in male mice,
hepatoadenoma in female mice, and kidney tumors in male
rats. Based on the mouse oncogenicity data, an increased
cancer risk of 1x10"* is associated with about 100 jig/L
MTBE.
A brief overview was presented of the MTBE/gasoline
studies being conducted by the Centers for Disease Control
and Prevention to measure occupational and commuter
exposure to MTBE from its use during winter months of
MTBE-enriched fuels in regions that are in non-compliance
for the national ambient air quality standard (NAAQS) for
carbon monoxide. Data from Fairbanks, AK, showed el-
evated blood MTBE levels post-shift for occupationally-
exposed persons and post-commute for typical commuters.
Additional study areas were Stamford, CT, which also
implemented an oxyfuel program this past winter but with-
out the extensive publicity present in Fairbanks, and Al-
bany, NY, which did not use MTBE-enriched fuels and
served as an exposure control. Complete results of the study
are expected this summer to allow time for changes to the
oxyfuels program for next winter.
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Health Implications of Fish Contamination with
PCBs: The Mohawk Population in New York
.A large Superfund site on the St. Lawrence River in upstate
New York has contaminated downstream sediments with
PCBs to levels up to 5,500 ppm. The PCBs have migrated to
a Native American reserve where the native fish supports a
large proportion of the resident Mohawk population's diet
Of greatest concern are nursing mothers and pregnant
women. A study was undertaken to:
• Estimate maternal exposure to PCBs via ingestion of
fish and wildlife.
• Correlate maternal dietary exposure with concentra-
tions of 68 congeners in breast milk.
• Compare breast milk PCB concentrations in Mohawk
and local rural control populations (all of which are on
Women, Infants and Children subsidies).
• Correlate breast milk concentrations with concentra-
tions in infants' urine, using gas capillary gas chroma-
tography.
Follow mother/infant pairings from birth to 3 months
through sampling and questionnaires.
• Find methods for fingerprinting the congeners and
tracing them to their source.
The study concluded in April 1993, and some data are
available for concentrations in breast milk and dietary expo-
sure. Mohawk mothers who participated in 1986 to 1989
had higher levels of PCBs in their breast milk than did a
comparison group of Caucasian women from elsewhere in
upstate New York. These recent results show that the moth-
ers are following instructions to reduce their fish consump-
tion and to trim fat from the fish before cooking it, and, as a
result, their PCB levels are now similar to that of controls.
However, the change in lifestyle caused by the warnings
against fishing on the reserve has changed the tribe's qual-
ity of life for the worse, from encouraging the people to eat
less healthy meats to forcing them to look for alternative
income. Efforts to help the community return to traditional
ways include projects to introduce aquaculture.
An attendee wondered how quickly the PCB levels decline
in the breast milk after exposure. The speaker said there is a
only a gradual reduction, but especially if consumption is
decreased. The reduction rate varies with the congener.
Another attendee asked what concentrations were detected
in the milk. While the exposed population showed concen-
trations of 10 to 15 ppb, concentrations in the control group
were comparable to the population at large, as high as 2.5
ppm. The results regarding relative contribution are similar
to the findings of a study in Michigan.
Arsenic Contamination of Well Water: Case
Studies
A representative from the Wisconsin Division of Health
(DOH) described several cases of drinking water contami-
nation by arsenic. Normally, total arsenic exposure from
dietary sources is 50 ug/day; 15 to 20 ug/day inorganic
arsenic. In Wisconsin, the DOH found ten wells, serving
65,000 people, that contain arsenic at concentrations up to
10 ng/L. The state's northeastern portion (population 50,000
to 60,000) has unusually high concentrations in the drinking
water. Of the 1,000 private wells in the region, ten percent
show arsenic levels between 50 and 500 ug/L; 30 percent
contain arsenic at levels greater than 500 ug/L. Persons
exposed to 50 ug/L for 70 years have a cancer risk of 1Q-2.
Skin cancer, as well as liver, lung, bladder, and kidney
tumors, have been associated with exposure to inorganic
arsenic via ingestion. Noncancer effects observed in the
region are anecdotal only but include an increase in hepatic
enzymes from exposure to drinking water with concentra-
tions greater than 175 ug/L and gastrointestinal effects,
nonspecific neurological effects, and hyperpigmentation at
greater than 300 ug/L. The high arsenic levels are naturally
occurring and have been traced to a St. Peter's sandstone
formation between 300 and 600 feet below the surface.
DOH has prepared a preliminary study design to determine
a threshold for the noncancer effects observed in the area.
The state will offer water analysis kits to area well owners
for $20 and deliver an effects survey with the sample bottle.
Residents with high levels in the water will be asked to
submit hair and urine samples for analysis. DOH was able
to locate wells in the region because of a requirement to
register all wells with the state. An attendee asked what type
of treatment the state will recommend. The owners will be
advised to drill a new well to a different depth and to avoid
the sandstone, and they will be supplied with a list of
accepted treatment methods.
Health Concerns with Submersible Pumps
Wisconsin and Vermont have identified several models of
submersible pumps which leak PCBs and nonfood-grade oil
into drinking water wells. These pumps are often used when
external pumps do not supply sufficient power to transport
water from the well to the point of use. Until 1979, PCBs
were used as dielectric fluid in the pump capacitors. Some
PCBs leach from the capacitor with normal wear. If a PCB-
containing pump fails, the PCBs may leak into the drinking
water.
In addition, the Food and Drug Administration (FDA)
approved the use of food-grade mineral oil in the engine
housing. Wisconsin researchers discovered that some com-
panies used nonfood-grade oil. Such oils have been associ-
ated with skin cancer, immunologic anomalies, and liquid
pneumonia (via inhalation); furthermore, the oils could
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contain PAHs. Both Vermont and Wisconsin have been
thwarted in their efforts to determine from manufacturers
whether certain pumps contain nonfood-grade oil.
Wisconsin well owners who have submersible pumps are
advised to determine, as best they can, whether the pump
contains PCBs and have their drinking water tested for
PCBs and oil. The state has prepared an informational
booklet for homeowners that provides information about
the problem, how to test the drinking water, and how to
clean the well and replace the pump. The booklet also lists
pumps that could pose problems and laboratories across the
United States that are licensed to conduct PCB testing.
Vermont has had particular problems with manufacturers.
One oil supplier hired a consultant to conduct a risk assess-
ment of the oil and, based on a skin painting study, con-
cluded that there is no cancer risk. Therefore, the company
has argued against advisories published by the state.
An attendee asked if any alternatives to the submersible
pumps are available. New pumps which do not use oil in the
casing are one alternative. Another attendee wondered how
the states were able to locate the wells. Both states require
that the wells be registered with the state and that the pump
installation be permitted.
The next FSTRAC meeting is tentatively scheduled for the
fall in Washington, DC.
>• For more information about the next meeting or
FSTRAC in general, call Bob Cantilli (202-260-5546)
or Ed Ohanian (202-260-7571) in the Office of Water's
Office of Science and Technology.
CD-ROM (continued from p. 1)
The uncertainty module compares model prediction with
field data sets and determines relative bias, coefficient of
variation, and standard deviation ratio. Due to field data
limitations, this approach has only been applied to a subset
of the surface water models at this time. A key feature of
this module is the presentation of the information obtained
from the uncertainty studies using an easily understood
graphical relationship.
>• For additional information, please contact Rich
Walentowicz, Exposure Assessment Group, at 202-
260-8922.
Risk Assessment Library on CD-ROM
by Rich Walentowicz, 202-260-8922
EPA-OHEA has developed a Risk Assessment Library on
CD-ROM to provide exposure and risk information to the
user community in a convenient, easy-to-use format and to
demonstrate the use of this new media and technology for
distributing this information.
The CD-ROM contains about 200 documents which, in
paper copy form, would stack to a height of 12 feet. In
addition to saving space and paper, the disk gives the user,
for the first time, the ability to rapidly conduct full-text
searches for specific issues of interest and to copy text to
word-processing files. All tables and figures are provided as
images and are hyperlinked to the text.
The Risk Assessment Library consists of the assessments
prepared by OHEA for use in conducting exposure and risk
assessments and relevant documentation produced by other
EPA offices. This disk includes:
Health Assessment Documents,
Health Effects Assessments,
Exposure and Risk Assessments,
Miscellaneous methodology documents, and
Exposure and Risk Assessment Guidelines.
A complete list of documents is provided on an introductory
screen. Most of the documents summarize the scientific
literature, discuss environmental occurrence, and draw con-
clusions about the toxicity of the substances. Other docu-
ments describe the procedures and factors used in conducting
exposure and risk assessments.
The state-of-the-art searching and retrieval software is a full
Microsoft Windows* application that provides multiple fea-
tures such as a ranked relevance analysis, ability to build
thesauri, and hyperlinking to images and other sections.
Operating instructions are available through on-disk docu-
mentation as well as on-line help which is accessible from
all screens.
>• For additional information, please contact Rich
Walentowicz, Exposure Assessment Group, at 202-
260-8922.
Integrated Risk Information System (IRIS)
Highlights
by Patricia Daunt, 513-569-7596
Summarized below are the Integrated Risk Information
System (IRIS) highlights for the months of May and June.
More detailed NEWS is available for IRIS-2 users on the
first screen of the system.
May 1993 Update
Oral RfD Replaced (previously withdrawn):
Methyl ethyl ketone; CASRN1 78-93-3
Inhalation RfC Added:
Vinyl bromide; CASRN 593-60-2
1 CASRN is an abbreviation for the Chemical Abstract Service
Registration Number.
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June 1993 Update
Oral RfDs Added:
p-Chlorophenyl methyl sulfide; CASRN 123-09-1
p-Chlorophenyl methyl sulfone; CASRN 98-57-7
p-Chlorophenyl methyl sulfoxide; CASRN 934-
73-6
Inhalation RfC Added
Diesel engine emissions; CASRN not found
As of June 1, 1993, IRIS contained 511 chemicals. This
includes 342 oral reference doses (RfDs), 80 inhalation
reference concentrations (RfCs), and 216 carcinogenicity
assessments, bringing the total number of risk information
assessments to 638. In addition, IRIS also contained 75
Drinking Water Health Advisories, 388 EPA regulatory
action sections, and 95 supplementary data sections (chemi-
cal/physical properties).
>• For additional information, contact Patricia Daunt, IRIS
Database Manager, at 513-569-7596.
in. Regions
Region II
National Academy of Science Press Publications
of Interest
The Institute of Medicine has published a new study en-
titled "Indoor Allergens: Assessing and Controlling Ad-
verse Health Effects." The chairperson of the Institute of
Medicine committee that put the report together is Dr. Roy
Patterson.
On June 28, 1993, the National Research Council of the
National Academy of Sciences released a 386-page report
entitled "Pesticides in the Diets of Infants and Children."
The committee of 14 members was chaired by Dr. Philip
Landrigan from the Mount Sinai School of Medicine in
New York.
The National Research Council recently issued a report
entitled "Protecting Visibility in National Parks and Wil-
derness Areas." The committee was chaired by Dr. Robert
A. Duce, Dean of the College of Geosciences and Maritime
Studies at Texas A & M University. The report discusses
the need for a comprehensive national visibility improve-
ment strategy.
> For further information on obtaining copies of these
reports, contact the National Academy Press at 800-
624-6242 or 202-334-3313.
Contact:
Marian Olsen, 212-264-5682
IV. Meetings
llth Annual Occupational Health and Safety
Institute—August 23-September 3,1993
The llth Annual Occupational Health and Safety Institute
will be held August 23-September 3,1993, at the Midwest
Center for Occupational Health and Safety in St. Paul,
Minnesota. The institute will include courses in occupa-
tional health and safety including ergonomics and industrial
hygiene; electromagnetic fields and cancer, hazardous waste
management; health risk assessment; industrial and occupa-
tional toxicology, and occupational epidemiology.
>• For additional information on the training, please con-
tact the Registrar, Continuing Education, Midwest Cen-
ter for Occupational Health and Safety, 640 Jackson
Street, St. Paul, Minnesota 55101. The phone number
is 612-221-3992.
Society for Occupational and Environmental
Health Annual Conference—September 20-21,
1993
The Society for Occupational and Environmental Health
will hold its annual conference September 20-21, 1993, at
the Hyatt Regency Crystal City at Washington's National
Airport. The title of the conference is: Free Trade in North
America: The Occupational and Environmental Health Im-
pact
The purpose of the conference is to systematically explore
the anticipated public health consequences resulting from
industrial migration and new trade agreements leading to a
broad set of recommendations and proposed research. Data
on environmental and occupational health in North Ameri-
ca will be presented; and recent experiences from the Euro-
pean Community, Asia and the Pacific rim, the U.S.-Canada
trade agreement, and elsewhere will be reviewed.
>• For additional information on the conference contact
the Society for Occupational and Environmental Health
at 6728 Old McLean Village Drive, McLean, Virginia
22101. The phone number is 703-556-9222.
Biological Mechanisms and Quantitative Risk
Assessment: From Experimental Design to Risk
Management—November 1-4,1993
The U. S. EPA Health Effects Research Laboratory in
Research Triangle Park, NC, will hold a symposium, titled
"Biological Mechanisms and Quantitative Risk Assessment:
From Experimental Design to Risk Management,'' Novem-
ber 1-4,1993, in Research Triangle Park, NC.
The purpose of the symposium is to provide an opportunity
for active dialogue on the role of mechanistic biological
research in future risk assessment strategies. Specific goals
are to discuss the following issues:
10
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Current use of mechanistic biological data in quantita-
tive risk assessments,
The changing face of health effects risk assessments in
response to increasingly sophisticated knowledge of
the mechanisms of toxics effects and biological func-
tion, and
• Role of mathematical models of biological systems in
integrating research activities, identifying data gaps,
designing mechanistic studies, and reducing uncertain-
ties in the risk assessment process.
An opportunity will be provided for attendees to present
posters on topics related to the theme of the symposium.
Guidelines for submissions of abstracts will be sent to those
interested.
>• For additional information on the meeting and posters,
contact Research and Evaluation Associates, Inc., 100
Europa Drive, Suite 590, Chapel Hill, NC 27514. The
phone number is 919-968-4%! and the FAX number is
919-967-4098.
Healthy Cities Conference—December 8-11,
1993
The International Healthy Cities and Communities Confer-
ence will be held December 8-11, 1993, in San Francisco,
CA. The theme for the conference will be "Improving the
Quality of Life."
>• For more information, contact Dr. Leonard Duhl, Chair,
International Healthy Cities and Communities Confer-
ence, 2151 Berkeley Way, Annex 11, Third Floor,
Berkeley, California 94704. The phone number is 510-
540-2960 and the FAX number is 510-540-3472.
VII International Congress of Toxicology—
July 2-6,1995
The VII International Congress of Toxicology (ICT VII)
will be held in Seattle, WA, July 2-6, 1995. The program
will be based on the theme: "Horizons in Toxicology:
Preparing for the 21st Century." The meeting will be hosted
by the Society of Toxicology in conjunction with the Inter-
national Union of Toxicology.
>• For additional information, contact ICT/VH, c/o Soci-
. ety of Toxicology, 1101 14th Street, N.W., Suite 1100,
Washington, DC 20005-5601 or 202-371-1393. The
FAX number is 202-371-1090.
Risk and Decision-Making Course Schedule
The following is the schedule for the Risk and Decision-
Making courses through October
San Juan, Puerto Rico
San Francisco, CA
New York City
July 7-9
August 3-5
August 24-26
The following is the schedule for the Risk Communication
workshops through October
June 28-July 2
October 12-14
Honolulu, HI
San Francisco, CA
Contacts:
Jim Cole, 202-260-2747
Marian Olsen, 212-264-5682
Alvin Chun, 415-744-1022
Contacts:
Jerome Puskin
Linda Tuxen
Dorothy Patton
Dick Hill
Don Barnes
Dean Hill
Maureen McClelland
Marian Olsen
Jeffrey Burke
Elmer Akin
Milt Clark
Jon Rauscher
Mary Rouse
Suzanne Wuerthele
Arnold Den
DanaDavoli
OAR-RAD
ORD-OHEA
ORD-RAF
OPTS
SAB
NEIC
Region I
Region II
Region DJ
Region IV
Region V
Region VI
Region vn
Region Vffl
Region DC
Region X
202-260-9640
202-260-5949
202-260-6743
202-260-2897
202-260-4126
202-776-8138
617-565^885
212-264-5682
215-597-1177
404-347-1586
312-886-3388
214-655-8513
913-551-7415
303-293-0%!
415-744-1018
206442-2135
If you would like to receive additional copies of this and
subsequent Reviews or to be added to the mailing list
contact:
CERI Distribution
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
11
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