PUBLIC HEALTH ASSESSMENT
VELSICOL CHEMICAL CORPORATION (ILLINOIS)
MARSHALL, CLARK COUNTY, ILLINOIS
CERCLIS NO. ILD000814673
This section of the public health assessment describes environmental sampling previouslyconducted at the site and identifies contaminants of concern found in specific environmentalmedia. The selected contaminants are evaluated in subsequent sections of the health assessmentto determine whether exposure to them has public health significance.
IDPH selects contaminants for further evaluation based upon the following factors:
- concentrations of contaminants on and off the site;
- sampling locations and frequency, field data quality, and laboratory data quality;
- comparison of on-site and off-site concentrations with health assessment comparison values for noncarcinogenic and carcinogenic endpoints; and
- community health concerns.
It is emphasized that identification of a contaminant of concern in this section does not mean thatexposure to it will cause adverse health effects. As mentioned above, the potential for adversehealth effects resulting from exposure to contaminants of concern will be evaluated in subsequentsections of the health assessment.
The data tables include the following acronyms:
|CREG||=||Cancer Risk Evaluation Guide|
|EMEG||=||Environmental Media Evaluation Guide|
|LTHA||=||Lifetime Health Advisory|
|MCL||=||Maximum Contaminant Level|
|RMEG||=||Reference Dose Media Evaluation Guide|
|ppb||=||parts per billion|
|ppm||=||parts per million|
Comparison values for health assessment are contaminant concentrations in specific media that areused to select contaminants for further evaluation. These values include Environmental MediaEvaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevantguidelines.
EMEGs are media-specific screening values developed by ATSDR for use in selectingenvironmental contaminants of potential health concern. EMEGs are based on Minimal RiskLevel (MRL) and do not consider potential carcinogenic effects. CREGs are estimatedcomparison concentrations for specific chemicals based on one excess cancer in a million personsexposed over a lifetime. CREGs are calculated from ATSDR's MRLs. Maximum ContaminantLevels (MCLs) represent contaminant concentrations that EPA deems protective of public health(considering the availability and economics of water treatment technology) over a lifetime (70years) at an exposure rate of 2 liters of water per day. EPA's Lifetime Health Advisories(LTHAs) represent the level of a contaminant in drinking water (with a margin of safety) at whichadverse noncarcinogenic health effects would not be anticipated during a lifetime (70 years)exposure. While MCLs are regulatory concentrations, LTHAs are not.
EPA's Reference Dose (RfD) is an estimate of the daily exposure to a contaminant that is unlikelyto cause adverse health effects. Reference Dose Media Evaluation Guides (RMEGs) are derivedfrom EPA's RfDs.
The data presented in this subsection were collected during the RI conducted by Roy F. Weston,Inc. between August of 1986 and September of 1987. On-site contamination refers to all samplescollected from within the site boundary (fence) of the VCC Production Facility as shown in Figure 3.
Groundwater - Monitoring Wells
The extent of groundwater contamination was assessed during three phases of field investigation. In total, 40 groundwater monitoring wells nested over 18 locations (Figure 4) were installed andscreened. Well nests refer to groundwater monitoring wells located at the same location but atvarious depths. The siting of the well nests was designed to describe groundwater contaminationwithin the plant area, downgradient of the pond system, and upgradient of the plant area. Nineteen of the monitoring wells (designated as L and D wells) were screened into the lowerbedrock hydrogeological unit. The remaining 21 monitoring wells (designated as S and M wells)were screened into the upper hydrogeological unit (4).
Table 1 includes groundwater water monitoring data from both the shallow and deep aquifer. Wells screened into the unstabilized spur of the 5/6 Pond at location G205, and in the formerproduction area (wells G217M and G218) were significantly contaminated with volatile and semi-volatile organic compounds. Low concentrations of these compounds were found in wells westof the pond system. These findings indicated that organic constituents were greatly attenuated bythe geologic materials present at the site which appear to act as a barrier to the movement oforganic contamination. Additionally, inorganic metals contamination in groundwater was presentat low concentrations adjacent to and west of the 5/6 Pond and former Pond 2. However, nometals exceeded their comparison values except lead at 18 ppb. There was no general pattern forits occurrence on the site.
A review of the 11th round of groundwater monitoring conducted in May of 1994 indicated thatchlorobenzene was the only contaminant detected in the upper bedrock hydrogeological unit. Itwas detected at a concentration of 5.1 ppb which was slightly above the practical quantitationlimit of 5 ppb (10).
Soil (0 to 1.5 feet in depth)
Soil samples were collected throughout the site and adjacent areas. Figure 5 shows sample points in the former production facility. Surface soil by ATSDR's definition is soil located at a depth of0 to 3 inches. Table 2 reports the contaminants and concentration range. These soil samples were collected from a depth from 0 to 1.5 feet.
Range - ppb
|Reference||Comparisons Value |
- A - Action level for drinking water (USEPA)
Shallow aquifer (10-24 feet in depth)
Deep aquifer (25-55 feet in depth)
Hex - Hexachlorocyclopentadiene
|Date||Reference||Comparison Value |
The plant area soil characterization focused only on representative sampling of known orsuspected areas of contamination. These samples (borings) were collected with a truck-mounteddrilling rig and a stainless steel bucket auger. The results indicated that the plant area soils weresignificantly contaminated with organic and inorganic compounds. However, inorganiccompounds were not found at levels above comparison values.
The only pesticide detected in representative creek sediment sample was chlordane at a maximumof 0.0056 ppb; however, this concentration is less than the soil comparison value of 0.420 ppb. Low levels of volatile and semi-volatile organic and inorganic compounds were detected, but notat levels above comparison values.
Contaminants found in the unnamed tributary's sediment and water will serve as an indicator ofcontaminants that might be expected to have migrated downstream to off-site creek samplinglocations. There were no records reviewed that mentioned any removal activities or previousmaintenance activities at the site which might have biased the sampling results.
No pesticides were detected in creek water at any location on-site. Very low levels of organicand inorganic contamination were detected from creek water samples. However, no levelsdetected were above comparison values.
Volatile and semi-volatile organic compounds were detected in the sediments from Ponds 2 and 4. Benzene was found at levels above comparison values. Moderate chlordane and low levels ofheptachlor were found in sediments from Pond 2 (Table 3). Sediment contamination in the pondswas the result of contaminated runoff from the former production areas.
|Contaminant||Concentration Range-ppm||Date||Reference||Comparison Value |
The results of the air monitoring conducted at the site in September of 1987 demonstrated thatseveral volatile organic compounds were present at very low concentrations. However, most ofthese same compounds were also found in air samples collected at the background location. Thisair sampling was conducted to determine the nature of fugitive emissions from the on-site pondedareas.
Among the pesticide compounds analyzed, chlordane was found only in air samples collectedfrom two locations shown in Figure 7 (AS-2 and AS-4). However, hexachlorocyclopentadiene was detected in air samples from three locations (AS-2, AS-3, and AS-4) (4).
Air monitoring in July and August of 1991 was conducted to evaluate potential air contaminationon and around the perimeter of the site during excavation and grading of site soil. Volatileorganic and pesticide compounds were all found to be below the 8-hour threshold limit value (7).
Groundwater - Monitoring Wells
Figure 4 shows the number and locations of off-site monitoring wells that were sampled duringsite assessments in 1986-1987. Chloroform was detected in the lower aquifer. Cadmium wasdetected in the shallow and lower aquifer. These compounds were the only on-site contaminantsthat were detected in off-site groundwater; however, their concentrations were below comparisonvalues. Based on these monitoring data and the number of years (52) that disposal ofcontaminants has occurred at the site, it appears that significant reduction of groundwatercontaminants is occurring (4). Additionally, data obtained from the interim groundwatermonitoring program (1989-91) continue to confirm that groundwater downgradient of 5/6 Pondhas not been impacted by the site (9).
The results of pesticide analyses from the agricultural land soil samples (Figure 8) indicated thatpesticide contamination most frequently occurred west of the 5/6 Pond and southwest of Pond 2. Localized pesticide contamination was also found at two locations north of the plant. Volatilecontamination in the agricultural land soil was minimal. Moderate amounts of semi-volatilecontamination were detected only at location SB60 west of the 5/6 Pond. However, nocontaminants were detected above any comparison values of concern.
In February and May of 1987 as part of IEPA's RI, chlordane was detected in the unnamedtributary at a higher level (250 ppm) than on-site concentrations. This level was above thecomparison value. Low levels of volatile and semi-volatile organics and inorganics were found atlevels similar to on-site sample results.
In late 1988, sediment samples collected from the unnamed tributary west of Velsicol's property(Figure 6), showed elevated levels of chlordane. However, these levels were generally muchlower than found in the tributary sediment collected on Velsicol's property.
In August of 1991, the sampling results again showed lower levels of chlordane than detected onVelsicol's property, and in many cases lower levels of chlordane than detected in the 1988 sampleresults. All three sampling periods shown in Table 4 consisted of sediment samples collected from0 to 18 inches in depth. The highest levels of chlordane found off Velsicol's property werelocated immediately adjacent to the property line at S-3 and SD-13 (Figure 9).
|Concentration Range-ppm||Date||Reference||Comparison Value |
Organic and inorganic contamination was found in the unnamed tributary at similarly lowconcentrations detected on-site. These concentrations were below comparison values. Nopesticides were detected in creek water.
Fish species were collected from three trophic levels of the aquatic chain: bottom feeders,omnivores and predators. These fish were collected at three locations within the East Mill Creeksystem, downstream of the Velsicol plant and one location within the East Mill Creek systemprior to its confluence with East Mill Creek (Background). The fish fillet composites weresampled from Yellow Bull Head, Bluegill, and Crappie. These samples were analyzed for bothpesticides and PCBs. PCB compounds were not detected in any fish fillet samples. However,pesticides were detected as shown in Table 5. The composite sample had levels of dieldrin andchlordane below U.S. Food and Drug Administration (USFDA) limits (0.3 parts per million). Inaddition, a low level of benzene hexachloride was detected, but there are no USFDA limitsestablished for this compound. Of the fish caught during the fish sampling program (Figure 9), only one was of sufficient size to be considered edible (i.e. Black Crappie at FH 121 weighing 20oz. and 315 mm long). All other fish caught were well below any length or weight consideredreasonable for eating. No health advisory for fish was issued (6).
|Date||Reference||Comparison Value |
- J - Indicates an estimated value which is below the detection limit.
USFDA - United States Food and Drug Administration
Beta-BHC - Beta-Benzene Hexachloride
No sampling of cropland plants was conducted. Although cadmium and chlorinated hydrocarbonpesticides were detected in agricultural soil samples, the levels detected do not appear to be highenough to cause a bioaccumulation in plants and subsequent animal species who might eat theseplants.
Toxic Chemical Release Inventory (TRI)
A search was conducted of the USEPA Toxic Chemical Release Inventory (TRI) for the site andlocal area. This database contains information on environmental releases from active industrialfacilities (1987-1992). Table 6 summarizes environmental releases from the VCC, while Table 7 summarizes environmental releases from other industries in the area. This information is given toindicate if past or on-going emissions from manufacturing facilities in the area may be contributingan additional environmental burden to a potential population of concern. In this case, it does notappear that on-site or off-site TRI sources are likely to affect site-related contaminantconcentrations or impact the exposure pathways linked to the site.
- (1) Underground injection well
|Stanadyne, Inc. (Supermet Div)||Nickel Compounds||X||---||---|
|Supermet, Inc.||Nickel Compounds||X||---||---|
In preparing this Public Health Assessment, IDPH relies on the information provided in thereferenced documents and assumes that adequate quality assurance and quality control measureswere followed with regard to chain-of-custody, laboratory procedures, and data reporting. Thevalidity of the analysis and conclusions drawn for this Public Health Assessment is determined bythe availability and reliability of the referenced information.
Although all plant facilities have been removed, the site is still fenced and will continue to restrictpublic access. Access and land use restrictions will be adopted even after remedial actions arecompleted, thereby, minimizing the potential for future human contact with any hazards.
To determine whether nearby residents are exposed to contamination migrating from the site,IDPH evaluates the environmental and human components that lead to human exposure. Thispathway analysis consists of five elements: A source of contamination, transport through anenvironmental medium, a point of exposure, a route of human exposure, and an exposedpopulation.
IDPH categorizes an exposure pathway as a completed or potential exposure pathway if theexposure pathway cannot be eliminated. Completed pathways require that the five elements existand indicate that exposure to a contaminant has occurred in the past, is currently occurring, orwill occur in the future. Potential pathways, however, require that at least one of the fiveelements is missing but could exist. Potential pathways indicate that exposure to a contaminantcould have occurred in the past, could be occurring now or could occur in the future. Anexposure pathway can be eliminated if at least one of the five elements is missing and never will bepresent. The discussion that follows incorporates only these pathways that are important andrelevant to the site.
Past, current, and future exposure pathways are possible from contamination of fish in theunnamed tributary. Due to past site spills and overflow from on-site impoundments, hazardouswaste was released into the unnamed tributary of East Mill Creek. This resulted in contaminatedsediment downstream of the site. Fish in the unnamed tributary, have been exposed toorganochlorines, either directly by ingesting contaminated water and sediment or indirectly byconsuming other fish that had previously been contaminated with organochlorines from theenvironment.
As mentioned in the Environmental Contamination and Other Hazards Section, of theapproximately 128 fish caught during the fish sampling program, only 1 fish was of sufficient sizeto be considered edible. The distribution of fish sizes might indicate that the unnamed tributarybetween Velsicol's property and the earthen dam does not support a sufficient fish population forthe regular consumption of fish by local people. However, the collection of fish was often madedifficult because of rip rap and submerged logs in the unnamed tributary. It could be reasonedthat larger fish escaped underneath the seine during fish sampling. As such, it is assumed that fishalong the unnamed tributary channel could be consumed on a limited basis.
Future exposure to contaminated fish should decrease since the realignment and design of a newon-site creek channel has been completed and the old on-site unnamed tributary excavated 24inches in depth and backfilled with clay. This measure should minimize any further sedimentcontamination to the unnamed tributary.
Based on sediment data, past, current, and future exposure to chlordane exists from contaminatedsediment. This exposure point is the unnamed tributary. Considering the level of water in theunnamed tributary, it would be reasonable to assume that it is not used for recreational swimming. However, it potentially could be used by people wading into the tributary to about the ankles andpossibly the knees. Potential routes of exposure could include ingestion of sediment throughmouth and hand contact and dermal contact with contaminated sediments.
Ingestion of contaminated sediment would not be expected to be a primary route of exposuresince most sediments would tend to be washed off hands before contacting the mouth of someonewading in the tributary. Future exposure to contaminated sediment should decrease because ofthe aforementioned remedial activities. There were no records reviewed that suggested personsmight have been exposed to on-site pond sediments in the past through maintenance activities.
Worker-Waste Material Pathways (Air, Soil, and Dust)
Facility employees and site workers could have been exposed to site contaminants throughinhalation of contaminated air, ingestion of contaminated soil and dust, and skin contact withcontaminated soil and sediment. However, both groups should have worn appropriate personalprotective equipment and complied with applicable health and safety guidelines during plantoperations and cleanup.
There are no additional exposure pathways identified at this site.
In this section we will discuss the health effects in persons exposed to specific contaminants,evaluate state and local health databases, and address specific community health concerns. Toevaluate health effects, ATSDR has developed a Minimal Risk Level (MRL) for contaminantscommonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to acontaminant below which non-cancer, adverse health effects are unlikely to occur. MRLs aredeveloped for each route of exposure, such as ingestion and inhalation, and for the length ofexposure, such as acute (less than 14 days), intermediate (15 to 364 days), and chronic (greaterthan 365 days). ATSDR presents these MRLs in Toxicological Profiles. These chemical-specificprofiles provide information on health effects, environmental transport, human exposure, andregulatory status. In the following discussion, Toxicological Profiles for chlordane, dieldrin, andbenzene hexachloride were referenced.
Past, present, and future exposure to chlordane is possible to adults and children who eatcontaminated fish from the unnamed tributary. Since chlordane concentrations in fish were belowUSFDA guideline levels, an acute exposure was not estimated. However, an estimate of long-term exposure to chlordane from eating contaminated fish was achieved by assuming thatresidents consumed the U.S. daily intake (6.5 g/day) averaged over a year. Another assumptionwas that some residents receive all of their daily fish intake from the unnamed tributary which ismost likely an overestimate of exposure to chlordane.
For adults and children, the estimated ingestion exposure dose did not exceed ATSDR's oralMRL (0.00006 mg/kg/day) for chronic exposure to chlordane. Because the level of exposure isso low, these people are likely not to experience harmful health effects. Furthermore, estimates oflifetime cancer risk indicate that insignificant or no increased risk of developing cancer over alifetime exist for persons consuming the fish.
Exposure to chlordane has occurred and is occurring to persons who wade in the unnamedtributary and contact contaminated sediment. The amount of chlordane dermally absorbed fromsediment by adults and children does not exceed ATSDR's oral chronic MRL. Therefore, non-cancer health effects are not a concern. This was based on the assumption that only 4.2% of thechlordane contaminated sediment was absorbed through the skin into the body.
Estimates of lifetime cancer risk using 1987 sediment sampling data suggested a low increasedrisk of developing cancer over a lifetime for adults and no apparent increased risk of developingcancer over a lifetime for children. It was assumed that exposure to adults would be no more than5 days per week for 25 weeks per year for a total of 30 years; additionally, children's exposurewould be no more than l5 years. These assumptions err on the side of conservatism since water inthe unnamed tributary may not exist during some warmer months of the year. More recentsediment sampling has shown that chlordane contaminated sediment has decreased and, hence,present and future exposure to chlordane contaminated sediment should also decrease. Based onthe 1991 sediment sampling data, insignificant or no increased risk of developing cancer shouldoccur from persons exposed to the chlordane-contaminated sediment.
Dieldrin exposure through fish ingestion has occurred and is occurring in some residents who fishfrom the unnamed tributary. The same assumptions were made as in the chlordane evaluation. The estimated ingestion exposure dose did not exceed ATSDR's oral MRL (0.00005 mg/kg/day)for chronic exposure to dieldrin. Likewise, the lifetime excess cancer risk estimated for adults andchildren does not present an increased risk of developing cancer.
Benzene Hexachloride (Beta-BHC)
Beta-BHC exposure through fish ingestion has occurred and is occurring in some residents whoeat fish from the unnamed tributary. The same assumptions were made as in the two previousorganochlorines. The estimated ingestion dose did not exceed ATSDR's oral MRL (0.00lmg/kg/day) for chronic exposure to beta-BHC. Lifetime excess cancer risk estimates for adultsand children are insignificant. Future exposure to beta-BHC will decrease further as remedialactivities have eliminated site sources of contamination from entering the unnamed tributary.
A 1986 health study was performed of the mortality experience of all VCC employees who hadworked 3 months of more from January 1, 1946, when the manufacture of chlordane was begun,to June 30, 1985. This update of previous studies compared the mortality experience of thisgroup of workers with US workers. Results showed a generally more favorable experience thanUS workers, except the experience with strokes was less favorable than the US experience.
The study determined that cancer mortality was generally more favorable than the US experienceamong production workers, but not to a significant degree. It also determined that no unusualpatterns were found among deaths due to reasons other than cardiovascular, cerebrovascular, orneoplasms. This study further confirmed results from previous studies that there was nosignificant health risk from long-standing exposure to the amounts of chlordane present in thework environment of the VCC plant.
There was no other site specific health outcome data identified that was appropriate to this site. At this time, there are no plans to perform an evaluation of health outcome data because exposurewas limited to a small population. This small exposed population size would not provide anystatistically significant data.
Each of the community concerns about health are addressed as follows:
- 1. Are the chemicals at the site acutely toxic to a passerby?
No, off-site exposure to the chemicals at the site would not cause acute health effects. Presently,remedial activities have decreased the amount of contaminant concentrations that would promoteany chronic (long-term) health effects.
2. Does the eating of contaminated fish from the unnamed tributary cause a healthconcern?
Persons who consume or consumed fish from the unnamed tributary should not experienceadverse health effects from the three organochlorines mentioned.
3. Is groundwater contamination migrating into the unnamed tributary?
Prior to remedial activities at the site, contaminated groundwater was known to leach and migrateinto the unnamed tributary. However, this is currently not the situation since the unnamedtributary has been rechanneled and other remedial activities have contained and lessenedcontamination on-site.