1991-10-04 – ATSDR – West Lake Landfill – Preliminary Health Assessment for West Lake Landfill


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CERCLIS NO . MOD079900932
OCTOBER 4, 1991
Agency for Toxic Substances and Disease Registry
Section 104 (i) (7) (A) of the Comprehensive Environmental Response, Compensalion, and Liabilily Act of 1980
(CERCLA), as amended. st.ates ” … the term ‘health assessment’ shall include preliminary assessments of potential risks to
human health posed by individual sites and facilities, based on such factors as the nature and extent of contamination, the
existence of potential pathways of human exposure (including ground or surface water contamination, air emissions, and
food chain contamination), the size and potential susceptibility of the community wiLhin the likely pathways of exposure,
the comparison of expected human exposure levels to the short-Lenn and long-term health effects associated with
identified hazardous substances and any available recommended exposure or tolerance limits for such hazardous
substances, and the comparison of existing morbidity and mortality data on diseases that may be associated with the
observed levels of exposure. The Administrator of ATSDR shall use appropriate data, risks assessments, risk evaluations
and studies available from the Administrator of EPA.”
In accordance with the CERCLA section cited, ATSDR has conducted this preliminary health assessment on the data in
the site summary form. Additional health assessments may be conducted for this site as more information becomes
available to ATSDR.
The conclusion and recommendations presented in this Rea.Ith Assessment are the result of site specific analyses and are
nOL to be cited or quoted for other evalumions or Health Assessments.
Use of Lrade names is for identification only and does not constilutc endorsement by the Public Health Service or the
U.S. Department of Health and Human Services.
-. ..
CERCLIS NO. MOD079900932
Prepared by
Missouri Department of Health
Under Cooperative Agreement with the
Agency for Toxic Substances and Disease Registry
——————– — —
The West Lake Landfill, located in the City of Bridgeton, St. Louis County,
Missouri, was proposed for the National Priorities List (NPL) in October 1989.
Soil contaminated with radioactive waste from decontamination efforts at the
Cotter Corporation’s Latty Avenue plant in Hazelwood, Missouri, was dumped at
the landfill in 1973. The radioactive soil was used as cover over refuse and
in later years the radioactive soil itself was covered with additional soil
and debris. The area around the landfill consists mostly of industrial
buildings and business offices with small residential communities to the south
and east. Agricultural river bottom land borders to the west, but it is fast
being encroached upon by Earth City which is being developed for commercial
purposes. The site presents no apparent public health hazard because the
available data indicate human health is not currently being affected.
Exposures of concern could occur if ground water contamination increases and
spreads, exposed radioactive materials on the northwestern edges of the
landfill move off site, or on-site worker exposure increases. Continued
monitoring is recommended until additional environmental data is available to
assess the on-site and off-site contamination and help predict future
A. Site Description and History
The West Lake Landfill is a 200 acre tract located in the City of Bridgeton,
St. Louis County, Missouri (Fig. 1). The tract borders St. Charles Rock Road
on the northeast side and Old St. Charles Rock Road on the southwest. It is
northwest of Interstate 270 and about 4 miles west of the Lambert-St. Louis
International Airport. The tract was owned in its entirety by West Lake
Properties from 1939 to 1988. In 1988, most of the tract was sold to Laidlaw
Industries; however, West Lake Properties retained the two radioactively
contaminated areas through a subsidiary named Rock Road Industries. Laidlaw
Industries operates the landfill under a Missouri Department of Natural
Resources (MDNR) permit.
From 1939 to 1987, limestone was quarried at the site. In 1962, landfill
operations commenced using old quarry pits to receive municipal refuse,
industrial waste, and construction debris. Also located on the property is an
active industrial complex producing concrete ingredients and aggregates.
The landfill is located on the historical edge of the Missouri River alluvial
valley, with about 75 percent of the site being located in the floodplain.
Soils at the demarcation line vary from Missouri River alluvium to upland
loessal soil. The present channel of the Missouri River lies just under 2
miles west of the landfill. The floodplain area and new businesses/industries
being constructed there are protected by a flood control levee. The ground
water level in the Missouri River floodplain is generally within 10 feet of
the surface. The reported flow is to the northwest from the site toward the
Missouri River.
In 1973, approximately 43,000 tons of soil contaminated with barium sulfate
residues containing about 7 tons of uranium and its radioactive decay products
were placed in the landfill. The radioactive material consists primarily of
uranium (U-238), thorium (Th-230), and radium (Ra-226). The soil came from
decontamination efforts at the Cotter Corporation’s Latty Avenue plant in
Hazelwood where the material had been stored. In 1980-81, The Radiation
Management Corporation (RMC), under contract to the Nuclear Regulatory
Commission (NRC), conducted a detailed radiological survey of the West Lake
Landfill. Material was found to have been dumped in two areas (Fig. 2). Area
1 is located near the landfill main office and covers approximately 3 acres.
It contains about 20,000 cubic yards of radioactive contaminated soil buried
about 3 to 5 feet deep. It is located over a former quarry pit which was
previously filled with debris. Area 2 covers about 13 acres and lies above 16
to 20 feet of debris. The radioactive contaminated soil forms a layer from 2
to 15 feet thick consisting of approximately 130,000 cubic yards. Some of
this contaminated soil is at or near the surface, particularly along the face
of the northwestern berm.
In 1983-1984, the University of Missouri-Columbia (UMC) Department of Civil
Engineering, under contract to the NRC, further characterized the site and
evaluated potential remedial measures. In 1986, Oak Ridge Associated
Universities (ORAU) sampled well water on and close to the landfill to
determine if radioactive material had migrated into the ground water. Based
on the reports of these studies, the site was proposed for inclusion on the
National Priorities List (NPL) in 1989.
B. Site Visit
On March 21, 1990, representatives of the Missouri Department of Health (DOH),
the Agency for Toxic Substances and Disease Registry (ATSDR), Environmental
Protection Agency (EPA), and MDNR visited the West Lake Landfill site. The
president of West Lake Properties led a tour of the area. He showed the group
the two areas with radioactive contamination and reviewed the history and
current operations at the site.
It was noted during the site visit that the entire facility is now fenced, a
security project completed in 1989. Before the fencing, employees present
during working hours and security guards present after working hours helped
prevent unauthorized access. The two areas of radioactive contamination were
not readily identifiable or marked. Area 2 did have a temporary row of
barrels to indicate the approximate eastern boundary. The only persons having
regular access to the area are the site’s work force.
During the time of the visit, the weather was clear and it had not rained for
a few days. Area 1 had a few small puddles of standing water and good
vegetative ground cover with no obvious erosion problems. Area 2 had no
vegetative ground cover, but had a variety of soil and crushed limestone
cover. Drainage was good with the ground being dry except in the northernmost
end where some water had pooled. Some recent dumping of apparent construction
debris was being used to fill in the low area where the water was standing.
Physical hazards at the site consisted of discarded construction equipment and
miscellaneous construction debris. After the NPL site visit, a driving tour
was conducted of the surrounding off-site area to determine possible routes of
exposure, demographics of the area, land use, and the possible population at
C. Demographics, Land Use, and Natural Resource Use
The West Lake Landfill is located in the northwestern portion of the City of
Bridgeton, in St. Louis County, Missouri. Earth City Industrial Park is
located on the floodplain approximately 1 mile west of the landfill.
Population density on the floodplain is generally less than 26 persons per
square mile; the daytime population (including factory workers) is much
greater than the number of full-time residents.
Major highways in the area include Interstate 70 (I-70) and Interstate 270
(I-270), which meet south of the landfill. The Earth City Expressway and St.
Charles Rock Road lie, respectively, west and east of the landfill. The
Norfolk and Western Railroad passes about 1/2 mile from the northern portion
of the landfill. Lambert-St. Louis International Airport is located
approximately 4 miles east of the West Lake Landfill.
In addition to business/industries at Earth City, plants are operated by
Ralston-Purina and Hussman Refrigeration across St. Charles Rock Road. The
employees of these two plants probably comprise the largest group of
individuals in close proximity to the contaminated areas for significant
periods of time. Considering that land in this area is relatively inexpensive
and that much of it is zoned for manufacturing, industrial development on the
floodplain will likely increase in the future.
Two small residential communities are present near the West Lake Landfill.
Spanish Lake Village consists of about 90 homes and is located about 1 mile
south of the landfill, and a small trailer court lies across St. Charles Rock
Road, 1 mile southeast of the site. Subdivisions are presently being
developed 2 miles east and southeast of the landfill in hills above the
floodplain. Ten or more houses lie east of the landfill scattered along
Taussig Road. The City of St. Charles is located on the west bank of the
Missouri River about 2 miles from the landfill.
Areas south of the West Lake Landfill are zoned residential; areas on the
other sides are zoned for manufacturing and business. Most of the landfill is
zoned for light manufacturing (M-1). However, some of the northern portion of
the landfill is zoned for residential use; this includes the contaminated area
around the former Butler-type building site in Area 2. The field northwest of
the landfill between Old St. Charles Rock Road and St. Charles Rock Road is
under cultivation. Trends indicate that the population of this area will
increase, but the land will probably be used primarily for business/industrial
No public water supplies are drawn from the alluvial aquifer near the West
Lake Landfill. It is believed that only one private well in the vicinity of
the landfill is used as a drinking water supply. In 1981, analysis showed
water in this well to be fairly hard (natural origins), but otherwise of good
Water supplies are drawn from the Missouri River at mile 29 for the City of
St. Charles, and the intake is located on the north bank of the river.
Another intake at mile 20.5 is for the St. Louis Water Company’s North County
The City of St. Louis takes water from the Mississippi River, which joins the
Missouri River downstream from the landfill. In this segment of the river,
the two streams have not completely mixed and the water derived from the
Missouri River is still flowing as a stream along the west bank of the
Mississippi River channel. Reportedly, the intake structures for St. Louis
are on the west bank of the river so that the water drawn may or may not be
mixed, depending on conditions.
D. State and Local Health Data
The Missouri Department of Health, State Center for Health Statistics,
analyzes and consults on health related information collected from several
sources. The Center’s Bureau of Health Data Analysis has available
statistical information, hospital discharge data, and the Multi-Source Birth
Defect Registry. The Multi-Source Birth Defect Registry consists of birth
outcome data from the following data sources: birth, death, hospital
—- ——–
discharge, Crippled Children’s Services, and Neonatal Intensive Care Unit
For health assessments, cancer mortality rates by age, sex, and cancer site
are calculated to determine whether there is a significant difference between
the area of concern and the rest of the State. Birth data include fetal
deaths, low birth weight births, and frequency of malformations in the area of
concern with comparison to the State rate.
For most of the State, the smallest geographic area that can be studied is
defined by a zip code. In the St. Louis metropolitan area, census tract
information is available that allows further refinement of the potentially
exposed population. However, that may still represent a larger area than is
actually affected by a site such as West Lake Landfill and the additional
people in the study group may well dilute and obscure any adverse health
outcomes, if present.
Community concern around the area seems to be minimal. The Missouri
Department of Health (DOH) has had contact with area residents through the DOH
private well water monitoring program. The residents have expressed interest
in the results of the water sampling., but have expressed no particular health
concerns. Newspaper articles have been published about the site and its
possible hazards and public concern about this site may increase in the future
because of its link to three radioactive waste sites near the St. Louis
airport. The three sites – Futura Coating Company, Hazelwood Interim Storage,
and St. Louis Airport – have been consolidated and listed on the NPL as the
St. Louis Airport/HIS/Futura Coating Site. These sites have generated
considerable interest and debate including involvement of a local
environmental group. Their interest may extend to West Lake as the
radioactive waste there came from the St. Louis sites.
A. Public Comment Response
In order to solicit public comment on the West Lake Landfill Preliminary
Health Assessment, the document was made available to the public as required
under the Missouri Department of Health cooperative agreement with ATSDR.
The Health Assessment was placed at four readily accessible repository sites
(City of Bridgeton, City Hall; Bridgeton Trails Branch, St. Louis County
Library; Murphy Health Center; and the St. Louis County Department of
Community Health and Medical Care) for a period of 30 days (April 29 –
May 29, 1991).
Notification of the availability of the Preliminary Health Assessment was in
the form of a news release on April 23, 1991, followed by two public notices
in the Sunday St. Louis Post Dispatch on May 5, 1991, and May 19, 1991. No
comments were received during the public comment period for the West Lake
Landfill Preliminary Health Assessment.
A. On-Site Contamination
In 1980-81, a radiological survey of the West Lake Landfill was conducted by
the Radiation Management Corporation (RMC) of Chicago, Illinois. External
(gamma) radiation levels in microrems per hour (-R/Hr) were measured 1 meter
above the ground surface. This survey showed the radioactive contaminants to
be located in two areas of the landfill (Fig. 2). Both areas had places that
exceeded 100 -R/Hr with a maximum level as high as 3,000 to 4,000 -R/Hr
detected in Area 2. The total areas exceeding 20 -R/Hr were about 2 acres in
Area 1 and 9 acres in Area 2. Levels were again measured in May (Fig. 2) and
in July of 1981 and found to be significantly lower than the November 1980
sampling, especially in Area 1 where approximately 4 feet of sanitary fill had
been added. An equal amount of construction fill was added to most of Area 2.
As a result, only a few hundred square meters of Area 1 exceeded 20 -R/Hr and
the amount of Area 2 exceeding 20 -R/hr had decreased by about 10 percent with
a maximum reading of about 1600 -R/hr. The 20 -R/hr criterion was derived
from the NRC’s Branch Technical Position, 46 CFR 52061, October 23, 1981,
which aims at exposure rates less than 10 -R/hr above background levels.
Background radiation in the area is about 10 -R/hr.
Surface Soil Analysis
Surface soil samples were gathered and analyzed (1980-81) on site for gamma
activity. In all 61 surface soil samples, only uranium and/or thorium decay
chain nuclides and K-40 (potassium 40) were detected. On-site samples ranged
from about 1-21,000 picocurie per gram (pCi/gram) for Radium 226 (Ra-226) and
from less than 10 to 2,100 pCi/gram Uranium 238 (U-238). Off-site background
samples were on the order of 2 pCi/gram for Ra-226. In general, surface
activity was limited to Area 2, with only two small regions in Area 1 showing
surface contamination.
Subsurface Soil
Subsurface soil was measured by the drilling of 43 holes, with holes being
drilled in known contaminated areas and then additional holes being drilled at
intervals in all directions until no further contamination was detected.
Concentrations of Ra-226 ranged from less than 1 pCi/gram to 22,000 pCi/gram.
Ground water
In the fall of 1980, and the spring and summer of 1981, a total of 37 water
samples were taken and analyzed by RMC. One sample taken of standing water
near the Butler building in Area 2 equaled the EPA drinking water standard for
In 1981, MDNR collected 41 water samples that RMC analyzed for radioactivity,
but only 10 were shallow ground water standing in bore holes. Of these 10
samples, only one equaled the EPA gross alpha activity standard for drinking
water of 15 picocuries per liter (pCi/L). Four of the 10 shallow ground water
samples exceeded 30 pCi/L gross beta activity, ~ith most of the beta activity
coming from naturally occurring K-40 as determined from subsequent isotopic
analysis. Background activity is estimated as 1.5 pCi/L gross alpha activity
and 30 pCi/L gross beta activity.
In 1983, and again in 1984, eleven perimeter wells were sampled for gross
alpha and gross beta. In two years of sampling, only 1 well each year
exceeded the 15 pCi/L drinking water standard for gross alpha (18.2 pCi/L in
1983 NE boundary, and 20.5 pCi/L in 1984 W boundary). Only one well in 1983
exceeded 30 pCi/L gross beta activity level at 33.1 pCi/L gross beta.
In 1986 Oak Ridge Associated Universities (ORAU) personnel took water samples
from 44 perimeter wells. Only one well (17 pCi/L of gross alpha activity)
exceeded the drinking water standard. This well also contained 47 pCi/L gross
beta activity. This well, and another at 46 pCi/L were the only ones to
exceed the 30 pCi/L background gross beta activity level. These wells are
close to one another on the west boundary of the landfill.
No elevated radioactivity was found by RMC in vegetation consisting of on-site
weed samples and farm crop samples (winter wheat) located near the northwest
boundary of the landfill. This crop location was chosen for sampling because
water could run off from the fill onto the farm field.
Concentrating on measuring radon and its daughters in the air, both gaseous
and particulate airborne radioactivity were sampled and analyzed between May
and August of 1981. These were sampled because of the known materials that
consisted partially or totally of uranium ore residues. A total of 111
samples from 32 locations were sampled and radon flux levels ranged from 0.2
pico curie per square meter-second (pCi/m2-sec)in low background areas to 865
pCi/m2-sec in areas of surface contamination. A set of air particulate
samples was taken to assess radon daughter concentration. Radon daughter
concentration is commonly reported in terms of working level (WL), a unit of
measurement originally developed for occupational exposure but also relevant
and appropriate for environmental exposure. The highest levels (0.031 WL)
were detected in November 1980, near and inside the Butler-type building, that
has since been removed. Off-site samples were taken for background at Earth
City, Taussig Road, and Old St. Charles Rock Road sites. The levels measured
were reported at 0.0011, 0.005, and 0.0017, respectively.
Other Contaminants
The site has been a landfill since 1962. Prior to regulation by the MDNR, it
is believed that the landfill may have accepted such materials as organics and
inorganics, heavy metals, solvents, pesticides, paints and pigments, acids,
bases, sewage sludge, as well as small quantities of unknown hazardous waste.
This is based on notification as required by the Comprehensive Environmental
Response, Compensation and Liability Act of 1980 (CERCLA) and may not be an
accurate representation of what was actually dumped in the landfill. (A
portion of CERCLA 103(c) requires owners and operators of facilities which had
stored, treated, or disposed of hazardous substance to notify the
Administrator of EPA of the existence of such facilities not later than
June 11, 1981. This requirement effectively obligated all owners and
operators of such facilities to report the existence of facilities that they
knew to have used at any time in the past for the storage, treatment or
disposal of hazardous waste.) (10)
The sampling data available for the site have not demonstrated significant
contamination of the ground water. Burns and McDonnell, in a 1986 report on
the hydrogeology of the site, reported to have found only methylene chloride,
bis (2-ethylhexyl) phthalate, and phenol in identifiable quantities in 2
rounds of sampling (December 1985 and May 1986). They also reported that the
general distribution of the organic constituents was scattered and irregular.
In round 2 of the sampling, the presence of methylene chloride was attributed
to the laboratory process rather than to any contaminant in the ground water.
In general, the detection of organics and heavy metals was scattered and
irregular, leaving inconclusive evidence as to the contamination of the
landfill by these materials.
B. Off-Site Contamination
Off-Site contamination from the West Lake NPL site has not been shown. The
Missouri Department of Health sampled private wells in the area most likely to
be contaminated. Four wells were sampled in 1988 and 1989 and no gross alpha
activity above the EPA drinking water standard of 15 pCi/l was found. The
samples were also tested for the presence of common pesticides. None were
detected in any of the samples.
The possibility exists that during the transportation of the radioactively
contaminated soil to the West Lake Landfill, some soil could have blown or
spilled from the transportation trucks. This is being investigated in
conjunction with the St. Louis Airport/HIS/Future Coating NPL site by a
contractor for the U.S. Department of Energy.
Research of the EPA Toxic Chemical Release Inventory (TRI) was conducted to
determine other chemical releases in the area of West Lake Landfill. Three
industries in the vicinity reported releases in the years 1987 and 1988, two
of which are within a mile of the site, while the third is just over a mile.
Releases of reported chemicals had no correlation with the West Lake Landfill
C. Quality Assurance and Quality Control
Various organizations and laboratories have been involved in the sampling and
analysis with varying degrees of Quality Assurance and Quality Control
information available. In preparing this Preliminary Health Assessment,
DOH/ATSDR have, to an extent, relied on the information provided in the
referenced documents and assume adequate quality assurance and quality control
measures were followed with regard to chain-of-custody, laboratory procedures,
and data reporting. The validity of the analysis and therefore the
conclusions drawn for this health assessment are predicated on this reliance.
D. Physical and Other Hazards
Physical hazards at the site consist of discarded construction equipment and
miscellaneous waste construction debris around Area 2. The area is fenced and
only workers at the site would be expected to be exposed to possible hazards.
As discussed in the Site Description and History Subsection, the dumping of
approximately 43,000 tons of soil contaminated with barium sulfate residues
containing approximately 7 tons of uranium and its radioactive decay products
has polluted the West Lake Landfill.
A. Environmental Pathways (Fate and Transport)
Radioactive contaminated soil was used to cover debris and municipal waste at
the West Lake Landfill. The contaminated soil has since been covered over
with clean soil and remains exposed only in an area on the northwestern berm.
Erosion of this soil by surface water run-off would spread radioactive
contamination to the farm field west of the site and/or to the Creve Coeur
Creek. The creek has no known recreational purposes and is not expected to be
used for a water source. Approximately two miles downstream, the creek enters
the Missouri River. Water supplies for the City of St. Charles are drawn from
the opposite (north) bank of the river. The next known water intake is the
St. Louis Water Company North County Plant, which is approximately 8.5 miles
further downstream.
Wind erosion of dust from the berm is not expected to be a pathway of concern
except in very dry conditions or during disturbance. The landfill is located
on the historical edge of the Missouri River alluvial valley with about 75
percent of the site being located in the floodplain. There are two aquifiers
at the site consisting of the Missouri River alluvium and the shallow
limestone bedrock. Below the s~allow limestone is the relatively impermeable
Warsaw shale that acts as a barrier, making contamination of the deeper
limestone aquifer unlikely. The shale layer has been reached by quarrying
operations but has not been disturbed.
Ground water flow direction in the river floodplain varies somewhat, depending
on the water level. It generally tends to flow northwest toward the river.
Under high river conditions, the flow is more northerly. The ground water
level is generally within 10 feet of the floodplain surface. No public water
supplies are drawn from the alluvial aquifer near the West Lake Landfill. Any
leachate would be significantly diluted upon reaching the alluvial ground
water and further diluted once it reached the river.
The air above the contaminated soil provides a path for the dissemination of
radon gas. The gas and its alpha-particle emitting daughters then become
available for inhalation.
The high ratio of Th-230 to Ra-226 radioactivity indicates that decay of
Th-230 will increase the concentration of its product, Ra-226, until the two
radionuclides are in equilibrium. It is estimated that the Ra-226 activity
will increase by a factor of nine 200 years from now, and by a factor of
thirty-five 1,000 years from now. All radionuclides in the decay chain after
Ra-226 (and the Ra-222 gas flux) will be increased by similar multiples. (12)
B. Human Exposure Pathways
With the landfill being fenced, direct exposure to the contaminated soil on
the northwest berm to the public is not considered a viable route of exposure.
If the soil was eroded from the site by either wind or water, exposure to
radioactive materials could take place. Ground water in the area is not used
for municipal purposes, but a few private wells in the area are used for
domestic purposes and irrigation.
Surface water from the Missouri River used as a municipal supply for the City
of St. Charles is not expected to be affected by the landfill. The city draws
its water from the west bank where mixing has not occurred yet. The City of
St. Louis Water Company North County Plant takes its water from the Missouri
River at mile 20.5 where significant dilution of any possible contaminants
from the landfill has already occurred.
Radon exposure to the public is not expected to be a problem since the area is
fenced and there is no public access. Air levels off site would be typically
much lower than on site. The possibility does exist that, in the future,
increased levels of radon will be present as the material seeks equilibrium.
Ingestion of radioactive contaminants taken up by crops is not expected to be
a pathway of exposure. No elevated radioactivity was detected in on-site
weeds or in wheat grown near the site.
Fish from the Missouri River are not expected to be affected by the West take
Landfill primarily due to dilution. Fish in ponds along Creve Coeur Creek
west of the site may represent a potential exposure route; however, it is not
known if the ponds are used for fishing. The relatively low radioactivity in
the ground water in on-site monitoring wells would indicate that low activity
would be likely in any connected surface waters.
No exposure is known to be occurring to residents around the site. The few
private wells in the vicinity have not shown any contamination from the West
Lake Landfill; however, on-site monitoring well sampling has revealed some
migration of uranium and its radioactive decay products into the ground water.
The majority of the area is served by a public water system with no source
wells in the area. Direct exposure of the public to ionizing radiation on
site is not expected because of restricted access. Exposure to on-site
workers is expected to be of small concern because the time spent in
contaminated areas is likely to be brief and can be monitored and controlled
to minimize cumulative exposure.
The possibility does exist that during the unloading and disposal of the
contaminated soil at West Lake, the unprotected workers could have been
exposed. Information on radioactive level, worker protection, conditions
during the process, times per day and the duration of the project would be
needed to determine if significant exposure had occurred.
A. Toxicological Implications
Contaminants present at the landfill are Uranium-238 (U-238), Thorium-230
(Th-230), Radium-226 (Ra-226), and Radon-222 (Rn-222) with half-lives of
approximately 4.5 X 109 years, 80,000 years, 1,600 years, and 3.8 days,
respectively. These radionuclides, members of the uranium decay chain, emit
alpha particles and gamma rays. At this site, the uranium, thorium and radium
are nearly completely covered with clean fill so as to not present a
significant direct dust inhalation or ingestion potential. Therefore, the
exposures of most interest would be inhalation of radon and its daughters and
ingestion of radioactively contaminated ground water. Radon gas, produced by
the decay of radium, diffuses up through the soil cover and mixes with the air
above it where it may be breathed. Rain falling on the soil cover percolates
down into and through the contaminated layers, picks up radioactive particles,
and delivers them to the ground water where they may eventually reach drinking
water wells. Additionally, rain may erode contaminated soil from the
northwest berm area and deposit it in the adjacent field where crop uptake is
Rn-222 has been shown to be carcinogenic, producing lung cancers when inhaled,
based principally on studies of uranium miners. Although radon gas itself is
inert, some will be absorbed into the blood from the lungs and transported
throughout the body; the rest will be exhaled. The radon decay products
(daughters) are charged particles. When inhaled, either directly or attached
to other airborne particulate mateer, they deposit on lung surfaces and lodge
in the mucosa. As the radon daughters decay, they emit alpha particles, the
major health hazard associated with radon gas exposure. The alpha particles
are potent ionizers, but do not travel far in tissue due to their relatively
large size. (S,8)
The principal health effect of this ionizing radiation in humans is cancer
induction and the most important target tissue is the bronchial epithelium.
Due to their short half-life, inhaled radon daughters emit their alpha
particles in the lung before they move on to other organs. Radon exposed
smokers are at greatly increased risk of respiratory tract cancer due to the
multiplicative interaction of the dual exposure. (8)
By convention, radon exposure is measured in terms of working levels (WL) and
cumulative exposures over time are measured in working level months (WLM).
One WL is defined as any combination of the short-lived radon daughters in 1
liter of air that results in the ultimate release of 1.3 x 105 MeV (million
electron volts) of alpha particle energy. This is approximately the amount of
alpha energy emitted by the short-half-life daughters in equilibrium with 100
pCi of radon. (8)
Given that the highest level detected on site was 0.031 WL, and that this
level is very close to the Nuclear Regulatory Commission (NRC) alternate
concentration limit of one-thirtieth (0.033) WL for unrestricted areas (3), it
does not appear that unacceptably high exposure is occurring at present.
Additionally, the population at risk, on-site workers, would not experience
continuous exposure at the highest level. Rather, their actual cumulative
exposure would be to the weighted average of their work location levels. This
average would be well below the NRC concentration limit. There is
insufficient information available on the actual exposure of workers to
further characterize the risk.
Since the radioactive material at the site is not a natural undisturbed
deposit, the radionuclides are not in equilibrium with each other. Therefore,
it is quite possible that the concentration of radon gas will increase
significantly in the future. This increases the potential for future exposure.
When ingested, soluble forms of U-238 are chemically toxic to the kidney,
producing tissue damage in the proximal tubules and consequent functional
impairment. The tissue will regenerate and function will return if exposure
ceases. This chemical toxicity is of much greater significance than the
potential for ionizing radiation effects since the soluble forms are excreted
from the body rather quickly. Conversely, insoluble forms may be retained in
the body for a long time and the radiation effects become paramount. Target
organs are principally the bone marrow and lymphatics. Exposure may result in
radiation-induced cancer. (1,4)
Thorium is relatively inactive chemically and, therefore, is of concern only
as a chronic radiation hazard. Little of an ingested dose of thorium is
retained in the body; however, once deposited, it remains for a long time.
The bones, lungs, and lymphatics are the primary depositories.
Highly radiotoxic, radium is metabolically handled the same as calcium. It is
deposited in the skeleton where it serves as a source of alpha radiation in
the bones and adjacent tissues. Studies of radium dial painters have clearly
demonstrated excess bone cancer in heavily exposed groups. However, low
exposures have shown relatively much less risk of bone cancer than would be
predicted from a simple straight line extrapolation from the high exposure
data. (4)
B. Health Outcome Data Evaluation
Missouri State Health Outcome Data were researched for the West Lake Landfill
site in order to determine if there was an indication of common health
problems associated with the area. Although little public health concern was
present to warrant the research, it was useful to explore every available
avenue in determining public health effects that could be present around the
site. If an indicator of common health problems was found, and the problems
could not be related to the site, a follow-up health study would be considered
to investigate the cause.
The DOH, State Center for Health Statistics, studied cancer deaths and
natality data for the years 1981-1988 for the census tracts most likely to be
affected by the West Lake NPL site (Fig. 3). Using statewide cancer death
rates, the expected number of deaths was calculated for the West Lake area.
This number was then compared to the actual (observed) number of deaths and a
test of statistical significance performed. “Statistical significance” means
that any noted difference between the two numbers is probably not due just to
chance. Cancer deaths were looked at by type of cancer for various age
groups, for all types combined for age groups, and for total cancer deaths for
all age groups combined. Cancer of the kidney in the 45-64 age group was the
only comparison that achieved statistical significance. There were 3 observed
deaths in this group when less than 1 would have been expected. Small numbers
like this, however, may not allow meaningful analysis and it is unknown if
these persons actually experienced any exposure.
Fetal deaths and low birth weight weights (less than 2,500 grams) were studied
for years 1981-1988. The observed number of fetal deaths was not significant
compared to the expected value. The number of observed low birth weight
weights for the site area was significantly lower than expected.
Based on the State rate, a study of 1981-1986 births did not reveal an
observed number of anomalies significantly different from those expected.
This study was based upon aggregated birth and death certificates, hospital
discharge, Crippled Children’s Service, and neonatal intensive care unit data.
These studies neither confirm nor deny a health threat to the population
potentially at risk from the West Lake Landfill. The census tracts located
between the Missouri River and Highway 270 in north St. Louis County, (the
smallest definable area for these studies), include a much larger geographical
area and larger population than would actually be affected by this site;
therefore, any adverse health effects might be obscured.
From the information reviewed, the West Lake Landfill is presently judged to
be of no apparent public health hazard. No exposures above applicable levels
of concern are known to be presently occurring or to have occurred in the
past. The only suspected exposure at a level of concern would have been to
unprotected workers during past disposal of radioactively contaminated soil at
the site.
The relatively low levels of radioactive contamination in the ground water
suggest that the radionuclides present in the landfill are not very soluble.
Thus, they may not migrate significantly from the soil into the water.
Although radiation has been detected in some perimeter monitoring wells, the
results have been inconsistant from the various sampling rounds and additional
sampling is required to confirm the presence and magnitude of any
contamination. Off-site ground water samples have not shown alpha or beta
activity above the National Interim Primary Drinking Water Regulations
(NIPDWR) levels of 15 pCi/l and 50 pCi/l, respectively.
Sampling for priority pollutants, including heavy metals and organics, showed
no consistent pattern of on-site ground water contamination that could be
contributed to the landfill. DOH off-site sampling and analysis of private
well water revealed no detectable levels of pesticides, but the analysis did
not include volatile organic compounds (VOC’s) or metals.
Radioactive material at or near the surface of the west berm apparently has
not eroded from the site because no material was detected off-site or in
vegetation in 1981 data.
Radon gas is diffusing into the air above the contaminated areas, with maximum
levels (1981 data) approximately equal to the NRC alternate concentration
levels allowable for unrestricted areas. Current levels are unknown and
levels are expected to increase in the future as the material seeks
equilibrium. The potentially exposed population consists of the site work
force whose presence in contaminated areas is believed to be brief and
intermittent, reducing the cumulative exposure. No warning placards were
present in the March 1990 site visit to indicate the radioactive contaminated
area and to prevent inadvertent exposure. Earlier off-site sampling for radon
did not reveal levels indicating any increased air concentration.
The health outcome data evaluation was inconclusive. The study population was
much larger than those expected to be affected by the site. Community concern
seems minimal, and is being adequately addressed by the DOH well water
sampling and analysis program. Current sampling data is needed to better
evaluate the levels of contamination in the ground water, soil, and air.
Appropriate surveys need to be done both on and off-site so present pathways,
potential exposure, and health effects can be determined.
It is recommended that at the earliest possible date a comprehensive Remedial
Investigation/Feasible Study (RI/FS) be completed for the ‘West Lake Landfill.
It should include at least:
a. On- and off-site ground water monitoring for radiation
and other contaminants;
b. On- and off-site soil sampling (surface and sub-surface)
and determination of air radiation levels;
c. A complete survey of area wells and monitoring for
landfill contaminants;
d. Proposal and implementation of a remedial action to
prevent present and future exposure to workers and the
public, if deemed necessary by the RI/FS.
During the community interview phase of the Remedial Investigation,
information should also be gathered on former workers who were involved with
the site during the transport, dumping, and spreading of radioactively
——– ———– ——
contaminated soil. The workers could then be encouraged to talk to public
health officials at public meetings or availability sessions, or be personally
interviewed at their homes in order to determine their past exposures, site
related common health problems, and environmental circumstances during that
time. The DOH will work with the EPA and MDNR to address this issue.
At the earliest possible date, a placard system identifying the radioactive
areas must be installed in order to prevent inadvertent exposure. It is also
recommended that DOH continue to expand its monitoring of area wells in order
to include metals and VOC’s associated with the landfill.
When additional data, i.e., the RI/FS, become available, such material will
form the basis for further assessment by DOH/ATSDR at a later date.
In accordance with the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) of 1980, as amended, the West Lake Landfill NPL site
has been evaluated for follow-up health activities. There are no indications
that the surrounding community is or has been exposed to site contaminants.
Although worker exposure to site contaminants may have occurred in the past
during the period of contaminated soil dumping, spreading and covering
operations, it is believed that the exposure most likely did not occur at
levels deserving of public health concern. Considering the available
information, the site is not being considered for follow-up health activities
at this time. Should the Remedial Investigation discover new evidence
indicating actual or potential exposure of the public to site contaminants,
DOH/ATSDR will reevaluate this site for follow-up health activities.
Arthur Busch
Environmental Specialist
Missouri Department of Health
Stephen L. Meek
Missouri Department of Health
ATSDR Regional Representative
Dan Harper, R.S.
Senior Regional Representative
Region VII
ATSDR Technical Project Officer
Burt J. Cooper
Environmental Health Scientist
Division of Health Assessment and
Consultation, Remedial Programs Branch
This health assessment was prepared by the Missouri Department of Health under
a cooperative agreement with the Agency for Toxic Substances and Disease
Registry (ATSDR). It is in accordance with approved methodology and
procedures existing at the time the health assessment was initiated.
The Division of Health Assessment and Consultation, ATSDR, has reviewed this
health assessment and concurs with its findings.
.. C’
1. Berlin, M. and Rudell, B.; “Uranium” in Handbook on the Toxicology of
Metals, edited by L. Friberg et al. Elsevier/North-Holland Biomedical
Press, 1979
2. Burns & McDonnell. Hydrogeologic Investigation, West Lake Landfill
Primary Phase Report. Kansas City, MO. October 1986. Project No.
3. 10 CFR Part 20, App. B Concentrations in Air and Water Above
Natural Background
4. Casarett and Doull’s Toxicology: The Basic Science of Poisons. 3rd Ed.
edited by Curtis D. Klaassen, Mary 0. Amdur, and John Doull, Macmillan,
NY, NY, 1986
5. Harley, N .H.; “Environmental Lung Cancer Risk From Radon Daughter
Exposure” in The Risk Assessment of Environmental and Human Health
Hazards: A Textbook of Case Studies, Dennis J. Paustenbach, ed., John
Wiley & Sons, NY, NY, 1989
6. Missouri Department of Health. Cancer Registry and Natality Data
Analysis. West Lake Landfill,, Bridgeton, Missouri. 1990.
7. Missouri Department of Health.
Landfill, Bridgeton, Missouri.
Private Well Sampling Data, West Lake
8. National Research Council, Committee on the Biological Effects of
Ionizing Radiation (BEIR). 1988. Health Risks of RADON and Other
Internally Deposited Alpha-Emitters. Washington, DC: National
Academy Press.
9. Review of copies of EPA Form 8900-1, Notification of Hazardous Waste
Site, required by CERCLA 103(c). Missouri Department of Natural
Resources Site file, 1990.
10. Schroff, C. and Steinberg, R.E.; RCRA and Superfund – A Practice Guide
with Forms. Garland Law Publishing, New York, New York. 1989.
11. U.S. Nuclear Regulatory Commission. Office of Nuclear Material Safety
and Safeguards. Site Characterization and Remedial Action Concepts for
the West Lake Landfill. Docket No. 40-8801. July 1989.
12. U.S. Nuclear Regulatory Commission. Office of Nuclear Material Safety
and Safeguards. Radioactive Material in the West Lake Landfill.
NUREG-1308 Rev. 1 June 1988
13. U.S. Nuclear Regulatory Commission. Office of Nuclear Material Safety
and Safeguards. Radiological Survey of the West Lake Landfill. St.
Louis County, Missouri. NUREG/CR-2722. May 1982.
Figure 1.
Figure 2.
Figure 3.
” r
West Lake Landfill Area Map and Site Location
West Lake Landfill External Gamma Radiation Levels Map
May, 1981.
Missouri Health Outcome Data Census Tract Location Map
SCALE 1:24 000
1000 0 1000 2000 3000 4000 5000 6000 7000 FEET
– ..:E::3:::: E3 ~,__:…..,
‘ ..
AREA 2 t
~ … 20 .. R/hr
Figure 2 External gi.lnvna radiation levels, May, 1981
SOURCE: NRC, Radiological Survey of the Westlake Landfill, St. Louis Co., MJ 1982
Tollto. U.S.67
Census tracts area
West Lake Landfill
FIG. 3
+ :