Children's Blood Lead Investigation
Historically, inorganic lead has been released to the
environment by many human activities such as mining, smelting,
use of leaded gasoline, and manufacturing of batteries, plastics,
and chemicals. Lead is not volatile, so it usually moves through
the air as fine dust which deposits and contaminates soil within
a few miles of its source. People can be exposed to lead in air,
food, drinking water (and beverages), soil and dust, and across
the placenta before birth.
Important toxic effects of lead include anemia,
hypertension, and damage to the kidneys, testicles, and nervous
system. Small children are most sensitive to toxic effects of
lead because they suffer significant'losses in motor skills and
cognitive ability at lead doses which do not affect adults. EPA
considers children with blood lead levels of 10 or more
micrograms of lead per deciliter of blood to be at risk of
irreversible damage to the nervous system.
Chester officials provided records of over 10,000 blood lead
measurements for children, which EPA entered into a computer
database. Age and gender were not reported (although all were
reported to be seven years or younger at the time of the test),
nor was information available about how the children were chosen
for blood lead sampling. Lead concentration data for air, tap
water, soil, dust, and food were not available. This limited
database allowed EPA to compare blood lead levels in Chester with
those in similar Eastern cities, but did not support conclusions
about sources of lead exposure.
Average blood lead levels in Chester between 1989 and 1993
(Figure 4-16) were higher than 1990 averages in Boston,
Baltimore, or Cincinnati. However, blood lead in Chester
decreased significantly during this five-year period, so that in
1992 and 1993 Chester blood lead levels were similar to those in
Baltimore. With the limited database it was not possible to tell
if the decline in blood lead was real or artificial (caused by
sampling different groups of children or by medically treating
children with high blood lead levels).
EPA compared the Chester blood lead observations with
predictions from a computer model that predicts blood lead.
Because lead levels in Chester's air, water, soil, and food were
not available, EPA used national averages to make the
predictions. To match the Chester blood lead data it was
necessary to add 130 micrograms of lead intake per day to the
national averages.
EPA determined the average blood lead level for each
residence by combining multiple measurements from the same child
and from siblings. A map of blood lead levels in Chester was
prepared. The map showed no noticeable patterns of blood lead;
there appears to be no part of Chester where blood lead is higher
or lower than the others.
Overall, EPA's analysis of blood lead suggests that:
1. Recent measurements of Chester children blood lead levels
are similar to those in similar Eastern U.S cities.
2. Children in Chester receive lead exposures which are
substantially higher than the U.S. average.
3. It is not possible with the limited data available to tell
the source of the children's excess lead exposure.
4. The problem of high blood lead appears to be city-wide
rather than confined to specific neighborhoods.
AIR
Modeled Air Concentrations
As was previously noted, no new data was gathered for this
study. The recent years air data that existed was often developed
for specific purposes, e.g. compliance monitoring of permitted
emission parameters, or was presented in format which was not
compatible for risk calculation purposes. This presented a
pattern of data gaps in an important medium of concern, air.
It was decided that sufficient information existed regarding
the industry types, geographical locations, and production
capabilities, and that meteorologic data combined with actual or
generic emission levels could be utilized in a computer modeled
simulation of speciated ambient air quality.
Estimated air concentrations for 699 chemicals were provided
for approximately 1400 locations in Chester City. Of the
pollutants assessed, 640 are gaseous in nature, while 59 exist as
particulate matter2.
Although emission contributions from many sources were
modeled, only the total concentration of each pollutant at each
location was considered in risk calculations. Of the 699
chemicals evaluated, 122 have toxicity values in the form of
reference dose (RfDs) or cancer slope factors (CSFs). Five of the
modeled chemicals are criteria pollutants, and are regulated
under the authority of the Clean Air Act via the National Ambient
Air Quality Standards (NAAQS).
For chemicals with reference doses (RfDs) or cancer slope
factors (CSFs), modeling results were screened using RBCs as
described above to identify chemicals of potential concern
(COPCs). Accordingly, inhalation under a standard residential
exposure scenario was considered. In instances where both an RfD
and a CSF exist for a given COPC, only the most sensitive
endpoint (cancer or non-cancer) was evaluated.
Estimated criteria pollutant concentrations were compared to
the NAAQS. (This approach for evaluating potential threats is
similar to the methodoloqy employed for assessing non-cancer
threats posed by chemicals with RfDs.)
For gasoline and diesel, carcinogenic risks were assessed
based upon respective unit risks for these compounds, as
determined by a recent USEPA investigation (USEPA, 1993c).
For the criteria pollutants, predicted concentrations at
each grid location were compared to NAAQSs.
Individual Risks
At various locations in Chester, several chemicals were
predicted to exist in air at concentrations of potential concern.
Chromium VI was determined to contribute the most to
carcinogenic3 risk at any given location, while hydrogen
chloride presents the greatest non-cancer threat. A summary of
the highest individual risks in Chester City is presented in
Table 4-32 for carcinogenic COPCs, and in Table 4-33 for COPCs
with non-cancer endpoints.
None of the predicted concentrations of criteria pollutants
in Chester exceeded NAAQSs, as illustrated in Table 4-34.
Cumulative Risks
Cumulative carcinogenic risks and non-cancer threats are
predicted to exceed levels considered safe at several locations
in Chester City. The range of aggregate carcinogenic risks in
Chester as a result of inhalation is estimated to be l.lE-5 to
6.6E-54. For non-cancer endpoints, the range of Hazard
indices(HI) is predicted to be 1.0 to 3.8. The risks are also
displayed on Figures 4-29, 4-30, 4-31, 4-32, 4-33, and 4-34.
Cumulative values for the criteria pollutants were estimated to
range from 0.6 to 1.6. This is illustrated on Fig. 4-35.
It is possible to discuss the culpability of various sources
of air pollution to these risks. As outlined in the section on
air quality modeling, a large number of sources was modeled, the
sources vary dramatically in their contribution to both
carcinogenic risk and noncarcinogenic hazards.
Point sources accounted for roughly 40 percent of
environmental carcinogenic risk in Chester and more than half of
the sub-chronic risk. Delcora and Sun each contribute roughly
one quarter of the long-term cancer risk. Delcora and P.Q. Inc.
emit chromium and arsenic, Delcora emits those and other heavy
metals, and Sun emits many organic species. DuPont and
Westinghouse account for approximately 80 percent of the non-
cancer risk.
Area Source Emissions
County-wide estimated emissions were available for area
sources of air contaminants. These data were not conducive to
the performance of a quantitative risk assessment because of the
difficulty in identifying individual chemicals and separating the
Chester area out from the county. However, a qualitative/semi-
quantitative assessment follows.
Sources of toxic air releases which are small when evaluated
individually, but are significant when combined with other
facilities of similar type in a given geographic area are termed
area sources. Volatile organic compounds (VOCs) are of
particular concern because some are classified by USEPA as
probable or possible human carcinogens. Also, they
photochemically combine with oxides of nitrogen (N0x) and carbon
monoxide (C0) in the presence of sunlight to form ozone, which
causes respiratory problems and plant damage.
Information about area sources comes from two sources of
data. Information about the location, industry type, and number
of employees is available through Dun and Bradstreet.
Information about the amount of VOCs released per employee per
year is available in USEPA, l991d. Combining these two databases
gives an estimate of VOC emissions per facility per year.
A list of facilities with Standard Industrial Classification
(SIC) codes between 4000 and 9999 (which include businesses such
as transportation services, gasoline service stations, automobile
repair shops, and dry cleaners), and within the study area was
retrieved from the Dun and Bradstreet (D&B) data base.
[Facilities with SIC codes between 2000 and 3999 (manufacturing)
are reported in the TRI data base and are evaluated in the Air
Toxics Modeling portion of the study].
A grid system was established for the study area, with each
grid square approximately one square kilometer (or about 1/2 mile
by 1/2 mile), and the sum of the estimated emissions for each
facility within a given grid square was calculated. The values
for the grid system were assigned colors from red to green, with
grey indicating no facilities.
Fig. 4-36 shows the estimated emissions for all the grid
squares in the study area. Fig. 4-37 highlights the top 9 (15%)
grid squares, which represent estimated annual releases of VOCs
of over 40,000 pounds. Fig. 4-38 shows the minority distribution
of the study area with the 9 high squares indicated in cross-
hatching. This indicates that grid squares 6, 7, and 8 are in an
area with a very high percentage of minority population,
indicating that the potential for impact to the minority
community is greatest in these areas.
There are several limitations to the approach used to
estimate the VOC emissions for the area sources. First, the D&B
data base does not contain every facility in the study area that
releases VOCs. In addition, the estimates of VOC releases are
based on studies of "typical" facilities and are not actual
measures of the releases from the facilities in the study area.
The actual type and amount of VOC releases is not available. The
estimates are not identified for the specific SIC codes that were
identified in the D&B database, so that approximate values were
used instead of SIC code-specific ones.
EPIDEMIOLOGICAL ISSUES
A study of the existing public health status of the
community and a specific epidemiological study to try to
establish cause-and-effect links between environmental risks and
health effects were beyond the scope of the environmental risk
project. However, the state health department, as a preliminary
exercise, looked at the mortality rate for certain diseases in
the city as compared to the state and county. This exercise may
be found in Appendix III. This may give useful information
regarding the existing health of the community, although it
cannot be used to establish causes of the health conditions.
Surface Water, Sediment, Fish Tissue
Three main data sources were used for surface water,
sediment, and fish tissue data: the STORET database, CERCLIS
files, and the National Study of Chemical Residues in Fish.
The CERCLIS database was described previously. Five CERCLIS
sites in the Chester study area had surface water and/or sediment
data. These sites underwent data quality review in accordance
with the Quality Assurance Plans under which the work was
authorized.
The National Study of Chemical Residues in Fish was
performed by USEPA to study fish tissue contamination nationwide
(USEPA, 1992b). This study began as an outgrowth of the National
Dioxin Study, which found notable concentrations of dioxins in
fish tissue. It involved the collection of fish tissue from over
300 stations nationwide.
One station from this study was located within the Chester
study area, and these fish tissue results were used for the
Chester risk assessment. Analytical data were obtained in
accordance with the analytical procedures and quality assurance
plans cited in the national study.
Table 4-23 presents the risks associated with direct contact
with surface water at each location. It can be seen that the
Hazard Indices for each location are less than l, indicating that
significant adverse non-cancer health effects due to contact with
surface water at the reported concentrations are not expected.
Estimated cancer risks are at or below lE-6 for all locations
except the Delaware County Incinerator Landfill #l (3.9E-5). The
cancer risk at this site was based on arsenic and beryllium in a
drainage ditch water sample taken adjacent to the landfills. The
water sample was reported as "greenish brown" and is likely to
have contained high amounts of suspended solids. The feasibility
of people actually swimming in a drainage ditch depends upon its
depth and width, seasons of flow, and may also depend upon its
aesthetic appeal.
Table 4-24 presents the risks associated with direct contact
with sediment at each location. It can be seen that the Hazard
Indices for each location are less than l, indicating that
significant adverse non-cancer health effects due to contact with
sediment at the reported concentrations are not expected.
Estimated cancer risks were all below lE-5.
It is likely that most of the general population of Chester
does not consume locally-caught fish. However, subpopulations
may exist consisting of occasional fishers or possibly even
subsistence fishers. Subsistence fishers could have risks higher
than those quantitated herein.
Drinking Water
This study investigated the drinking water quality of both
private and public well users in the City of Chester and
surrounding municipalities including Marcus Hook Borough, Trainer
Borough, Chester City, Chester Township, Linwood, Upland Borough
and Eddystone Borough. The potability of the groundwater in the
study area and potential risk to private well users was evaluated
by qualitative assessment of the existing monitoring well data
from Comprehensive Environmental Response, Compensation, and
Liabilities Information System (CERCLIS) and Resource
Conservation and Recovery Act (RCRA) sites. Environmental equity
issues that would require further study were identified where
appropriate with respect to the data obtained to date.
Private Well Investiqation
The U.S.Department of Census data obtained in 1990 involved
a random door-to-door survey of the housing units (both vacant
and occupied) in the study area (see Table 4-1). An assessment
of the data indicated that less than 1% of the housing units in
the study area may obtain their drinking water source from
private wells. The Chester Water Authority and Health
Departments are not aware of any residential properties using
local groundwater for drinking or bathing purposes. The local
health department indicated that the entire population of Chester
is connected to a public water supply (PWS). However, the health
department did acknowledge that verification that none existed
would be quite difficult. Based on U.S. Census data there are an
estimated 61 private wells in the study area, of which
approximately 31 are believed to be dug wells and approximately
30 are believed to be drilled wells. The data are
extrapolations, from a smaller sample size, of the actual figures
that would have been obtained from a complete count (USDOC,
1990). Therefore, the exact number of private wells in the study
area is largely unknown.
Efforts to obtain locational information for any of the 61
private wells identified on the census tract (Figure 4-2) have
been hampered primarily because of those regulations which
protect census participants individual rights to privacy. It
should be noted that information retrieval from the census tract
is limited to a scale of census blocks which are a geographic
area of about 200 people.
Public Water Supply
Drinking water quality from public water sources in the
study area was investigated because greater than 99% of the
population is expected to obtain their drinking water from a
public supply. The study area is served by the Chester Water
Authority except for Eddystone, which is served by the
Philadelphia Suburban Water Company. It should be noted that
Philadelphia Suburban Water Company purchases water for Eddystone
from the Chester Water Authority. This water undergoes no
additional treatment; therefore, the actual source of drinking
water for Eddystone is the Chester Water Authority.
Tables 4-3, 4-4, and 4-5 summarize risks for the 1-year and
30-year exposure scenarios for the PWSs.
TOXIC RELEASE INVENTORY (TRI)
The TRI database contains information about chemical
releases from industrial manufacturers and processors (primary
Standard Industrial Classification (SIC) codes 20-39) to the
environment. Since 1987, facilities meeting established
thresholds have been required to report release data according to
section 313 of the Emergency Planning and Community Right-to-Know
Act of 1986 (EPCRA).
Region III has developed a method for evaluating these
releases in terms of their relative toxicity. This method is
documented in the Chemical Indexing System for the Toxic Chemical
Release Inventory Part I: Chronic Index (USEPA, 1993d). The
Chemical Indexing analysis provided in the present report
displays the 1992 TRI data in terms of the Chronic Index
(toxicity-weighted releases) and Residual Mass (non-weighted
releases) for Region III, highlighting TRI facilities in Delaware
County, Pennsylvania.
The Regional maps (Figures 4-26, 4-27, and 4-28) show TRI
releases in terms of the Chronic Index, including non-
carcinogenic and/or carcinogenic index dose. Those releases
which do not have an associated toxicity factor are combined
according to the amount of the release and are termed Residual
Mass. The resultant Chronic Indices and Residual Mass values are
summed for each facility and for each 8 x 8 mile geographic grid
area in Region III. Combining the facility Chronic Indices
within a geographic grid gives an indication of the potential for
cumulative hazard from TRI facilities within a given geographic
area.
In Delaware County, 28 facilities were subject to TRI
reporting under EPCRA for the reporting year (RY) 1992. A
summarized priority listing of these facilities is included in
Table 4-27 and a complete listing is provided in Tables 4-28 and
4-29. Table 4-27 shows a quantitative summary of the facilities
which ranked in the top 90th percentile - 95% confidence of the
28 facilities subject to reporting under EPCRA. Table 4-27 shows
the top six TRI facilities in the Chronic Index and Residual Mass
ranking.
It has not been determined whether these releases were
continuous for the entire year or if they reflect one-time
accidental releases or spills. In addition, the proximity of
these releases relative to potentially exposed populations has
not been established. The determination of a potential health
threat of the volumes released depends on the proximity of the
stack to residential areas, the surrounding terrain and the
meteorological conditions. Furthermore, should it be determined
that additional analysis is required at any site listed in this
report, documentation which identifies these release as
continuous or intermittent should be obtained prior to the
analysis.
OTHER ENVIRONMENTAL CONCERNS
One of the study objectives was to be responsive to
environmental concerns raised by the citizens in the study area.
Some of these were issues for which USEPA had no available
database and could therefore not assess with quantitative risk
assessment. These issues included odors and noise and are
addressed below.
Odors
Odor is a very difficult sensory phenomenon to describe
objectively. Many attempts and subsequently many descriptors
have been utilized in trying to describe the human olfactory
system and especially its variability, thresholds and the time
duration aspect of the sensation.
It is key to understand that many odors may be perceived at
concentrations as low as 1 part per billion (e.g. ammonia
ethylacrylate, isopropylmercaptan), while still others can be
detected as low as 1 part per trillion (e.g. n-butyric acid).
The mere ability to sense an odor does-not necessarily mean that
it is harmful at threshold levels. On the other hand, some
chemicals which are potentially harmful at low concentrations may
not be perceived by most humans at levels which are significantly
harmful. This certainly exacerbates individual fears and adds to
stress associated with the perceived odors which people
encounter.
A major source of concern in the Chester neighborhoods are
the odors which seem to emanate from the large industries along
the Delaware River coastline. It may be that individual small
industrial or commercial operations could be sources of these
emissions.
Although the incidence of odor complaints has been one of
the greatest concerns in Chester, the pervasiveness of odor could
not be addressed quantitatively in the environmental risk
assessment. This does not diminish the importance of odors to
residents, nor is it meant to ignore or screen them out of the
assessment. There were virtually no data available at the onset
of the study related to odors.
For purposes of this report, odors are being considered only
as a source of further investigation. They are a nuisance which
may add to the overall stress of residing in an urbanized
environment.
Noise
Many residents of Chester have complained that environmental
noise diminishes the quality of life they experience in a home
setting. They cite numerous sources of the noise and have
requested help from the industrial community and the
environmental agencies in reducing noise to acceptable, non-
intrusive levels. Some of the sources identified include:
truck traffic passing through residential areas
industrial operating equipment
aircraft over-flights
music sources, such as car radios, home hi-fi
train pass-by
As part of the Chester Risk Project, USEPA staff reviewed
applicable environmental noise studies performed in the Chester
area and performed a literature search for any applicable
mitigation measures. This limited search found a Pre-Operational
Noise Monitoring Study (Westinghouse, 1991) and a subsequent
Noise Report Summary (Westinghouse, 1993).
In the study, environmental noise monitoring was performed
at seven locations. This was considered to be background noise
monitoring, at facility site locations, prior to final
construction and operation of the Delaware County Resource
Recovery facility. A total of three continuous 24-hour time
periods were sampled including one weekend day and two weekdays.
An additional four locations were sampled in the residential
community in February 1991 in areas adjacent to the Resource
Recovery facility.
Although there was some variability in the measured noise
data due to short-duration transient events, the levels measured
in and around the facility and in the residential neighborhoods
are typical of urban residential settings and would be considered
generally acceptable.
A noise control ordinance for the City of Chester,
Pennsylvania was passed on January 14, 1993. This ordinance
applies to vehicles, appliances and equipment, and includes many
of the "nuisance" type of unwanted sounds. The ordinance
includes subjective aspects of noise as well as objective
criteria limits for motorized vehicles and property line limits
depending on land use zoning.
____________________________________
2 small solid particles like dust which move with air currents
3 cancer causing
4 1. lE-05 is a scientific notation used in risk characterization to
express an excess cancer risk in the general population of 1.1 persons out of
100,000 would be expected to incur (not die from cancer but incur a cancer) a
cancer above and beyond the normal incidence of cancer.
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Last modified: 11 November 1997
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