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1. ATSDR > Public Health Assessments & Consultations

This section of the public health assessment describes environmental sampling previously conducted at the site and identifies contaminants of concern found in specific environmental media. The selected contaminants are evaluated in subsequent sections of the health assessment to determine whether exposure to them has public health significance.

IDPH selects contaminants for further evaluation based upon the following factors:

1. concentrations of contaminants on and off the site;

2. sampling locations and frequency, field data quality, and laboratory data quality;

3. comparison of on-site and off-site concentrations with health assessment comparison values for noncarcinogenic and carcinogenic endpoints; and

4. community health concerns.

It is emphasized that identification of a contaminant of concern in this section does not mean that exposure to it will cause adverse health effects. As mentioned above, the potential for adverse health effects resulting from exposure to contaminants of concern will be evaluated in subsequent sections of the health assessment.

The data tables include the following acronyms:

Comparison values for health assessment are contaminant concentrations in specific media that are used to select contaminants for further evaluation. These values include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines.

EMEGs are media-specific screening values developed by ATSDR for use in selecting environmental contaminants of potential health concern. EMEGs are based on Minimal Risk Level (MRL) and do not consider potential carcinogenic effects. CREGs are estimated comparison concentrations for specific chemicals based on one excess cancer in a million persons exposed over a lifetime. CREGs are calculated from ATSDR's MRLs. Maximum Contaminant Levels (MCLs) represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) 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 which adverse 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 unlikely to cause adverse health effects. Reference Dose Media Evaluation Guides (RMEGs) are derived from EPA's RfDs.

A. On-Site Contamination

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 samples collected 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 and screened. Well nests refer to groundwater monitoring wells located at the same location but at various depths. The siting of the well nests was designed to describe groundwater contamination within 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 lower bedrock 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 former production area (wells G217M and G218) were significantly contaminated with volatile and semi-volatile organic compounds. Low concentrations of these compounds were found in wells west of the pond system. These findings indicated that organic constituents were greatly attenuated by the geologic materials present at the site which appear to act as a barrier to the movement of organic contamination. Additionally, inorganic metals contamination in groundwater was present at low concentrations adjacent to and west of the 5/6 Pond and former Pond 2. However, no metals exceeded their comparison values except lead at 18 ppb. There was no general pattern for its occurrence on the site.

A review of the 11th round of groundwater monitoring conducted in May of 1994 indicated that chlorobenzene was the only contaminant detected in the upper bedrock hydrogeological unit. It was detected at a concentration of 5.1 ppb which was slightly above the practical quantitation limit 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 of 0 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.

A - Action level for drinking water (USEPA)
Shallow aquifer (10-24 feet in depth)
Deep aquifer (25-55 feet in depth)
Hex - Hexachlorocyclopentadiene

The plant area soil characterization focused only on representative sampling of known or suspected areas of contamination. These samples (borings) were collected with a truck-mounted drilling rig and a stainless steel bucket auger. The results indicated that the plant area soils were significantly contaminated with organic and inorganic compounds. However, inorganic compounds were not found at levels above comparison values.

Creek Sediment

The only pesticide detected in representative creek sediment sample was chlordane at a maximum of 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 not at levels above comparison values.

Contaminants found in the unnamed tributary's sediment and water will serve as an indicator of contaminants that might be expected to have migrated downstream to off-site creek sampling locations. There were no records reviewed that mentioned any removal activities or previous maintenance activities at the site which might have biased the sampling results.

Creek Water

No pesticides were detected in creek water at any location on-site. Very low levels of organic and inorganic contamination were detected from creek water samples. However, no levels detected were above comparison values.

Pond Sediment

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 of heptachlor were found in sediments from Pond 2 (Table 3). Sediment contamination in the ponds was the result of contaminated runoff from the former production areas.

Air Monitoring

The results of the air monitoring conducted at the site in September of 1987 demonstrated that several volatile organic compounds were present at very low concentrations. However, most of these same compounds were also found in air samples collected at the background location. This air sampling was conducted to determine the nature of fugitive emissions from the on-site ponded areas.

Among the pesticide compounds analyzed, chlordane was found only in air samples collected from 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 contamination on and around the perimeter of the site during excavation and grading of site soil. Volatile organic and pesticide compounds were all found to be below the 8-hour threshold limit value (7).

B. Off-Site Contamination

Groundwater - Monitoring Wells

Figure 4 shows the number and locations of off-site monitoring wells that were sampled during site assessments in 1986-1987. Chloroform was detected in the lower aquifer. Cadmium was detected in the shallow and lower aquifer. These compounds were the only on-site contaminants that were detected in off-site groundwater; however, their concentrations were below comparison values. Based on these monitoring data and the number of years (52) that disposal of contaminants has occurred at the site, it appears that significant reduction of groundwater contaminants is occurring (4). Additionally, data obtained from the interim groundwater monitoring program (1989-91) continue to confirm that groundwater downgradient of 5/6 Pond has not been impacted by the site (9).

Subsurface Soil

The results of pesticide analyses from the agricultural land soil samples (Figure 8) indicated that pesticide 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. Volatile contamination in the agricultural land soil was minimal. Moderate amounts of semi-volatile contamination were detected only at location SB60 west of the 5/6 Pond. However, no contaminants were detected above any comparison values of concern.

Creek Sediment

In February and May of 1987 as part of IEPA's RI, chlordane was detected in the unnamed tributary at a higher level (250 ppm) than on-site concentrations. This level was above the comparison value. Low levels of volatile and semi-volatile organics and inorganics were found at levels 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 much lower 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 on Velsicol's property, and in many cases lower levels of chlordane than detected in the 1988 sample results. All three sampling periods shown in Table 4 consisted of sediment samples collected from 0 to 18 inches in depth. The highest levels of chlordane found off Velsicol's property were located immediately adjacent to the property line at S-3 and SD-13 (Figure 9).

Creek Water

Organic and inorganic contamination was found in the unnamed tributary at similarly low concentrations detected on-site. These concentrations were below comparison values. No pesticides were detected in creek water.

Biota

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 Creek system, downstream of the Velsicol plant and one location within the East Mill Creek system prior to its confluence with East Mill Creek (Background). The fish fillet composites were sampled from Yellow Bull Head, Bluegill, and Crappie. These samples were analyzed for both pesticides 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 and chlordane below U.S. Food and Drug Administration (USFDA) limits (0.3 parts per million). In addition, a low level of benzene hexachloride was detected, but there are no USFDA limits established 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 20 oz. and 315 mm long). All other fish caught were well below any length or weight considered reasonable for eating. No health advisory for fish was issued (6).

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 hydrocarbon pesticides were detected in agricultural soil samples, the levels detected do not appear to be high enough to cause a bioaccumulation in plants and subsequent animal species who might eat these plants.

Toxic Chemical Release Inventory (TRI)

A search was conducted of the USEPA Toxic Chemical Release Inventory (TRI) for the site and local area. This database contains information on environmental releases from active industrial facilities (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 to indicate if past or on-going emissions from manufacturing facilities in the area may be contributing an additional environmental burden to a potential population of concern. In this case, it does not appear that on-site or off-site TRI sources are likely to affect site-related contaminant concentrations or impact the exposure pathways linked to the site.

(1) Underground injection well

C. Quality Assurance And Quality Control

In preparing this Public Health Assessment, IDPH relies on the information provided in the referenced documents and assumes that 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 conclusions drawn for this Public Health Assessment is determined by the availability and reliability of the referenced information.

D. Physical And Other Hazards

Although all plant facilities have been removed, the site is still fenced and will continue to restrict public access. Access and land use restrictions will be adopted even after remedial actions are completed, 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. This pathway analysis consists of five elements: A source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population.

IDPH categorizes an exposure pathway as a completed or potential exposure pathway if the exposure pathway cannot be eliminated. Completed pathways require that the five elements exist and indicate that exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways, however, require that at least one of the five elements is missing but could exist. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and never will be present. The discussion that follows incorporates only these pathways that are important and relevant to the site.

A. Completed Exposure Pathways

Fish Pathways

Past, current, and future exposure pathways are possible from contamination of fish in the unnamed tributary. Due to past site spills and overflow from on-site impoundments, hazardous waste was released into the unnamed tributary of East Mill Creek. This resulted in contaminated sediment downstream of the site. Fish in the unnamed tributary, have been exposed to organochlorines, either directly by ingesting contaminated water and sediment or indirectly by consuming other fish that had previously been contaminated with organochlorines from the environment.

As mentioned in the Environmental Contamination and Other Hazards Section, of the approximately 128 fish caught during the fish sampling program, only 1 fish was of sufficient size to be considered edible. The distribution of fish sizes might indicate that the unnamed tributary between Velsicol's property and the earthen dam does not support a sufficient fish population for the regular consumption of fish by local people. However, the collection of fish was often made difficult because of rip rap and submerged logs in the unnamed tributary. It could be reasoned that larger fish escaped underneath the seine during fish sampling. As such, it is assumed that fish along 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 new on-site creek channel has been completed and the old on-site unnamed tributary excavated 24 inches in depth and backfilled with clay. This measure should minimize any further sediment contamination to the unnamed tributary.

Sediment Pathways

Based on sediment data, past, current, and future exposure to chlordane exists from contaminated sediment. This exposure point is the unnamed tributary. Considering the level of water in the unnamed 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 and possibly the knees. Potential routes of exposure could include ingestion of sediment through mouth and hand contact and dermal contact with contaminated sediments.

Ingestion of contaminated sediment would not be expected to be a primary route of exposure since most sediments would tend to be washed off hands before contacting the mouth of someone wading in the tributary. Future exposure to contaminated sediment should decrease because of the aforementioned remedial activities. There were no records reviewed that suggested persons might 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 through inhalation of contaminated air, ingestion of contaminated soil and dust, and skin contact with contaminated soil and sediment. However, both groups should have worn appropriate personal protective equipment and complied with applicable health and safety guidelines during plant operations and cleanup.

B. Potential Exposure Pathways

There are no additional exposure pathways identified at this site.

A. Toxicological Evaluation

Introduction

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. To evaluate health effects, ATSDR has developed a Minimal Risk Level (MRL) for contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. MRLs are developed for each route of exposure, such as ingestion and inhalation, and for the length of exposure, such as acute (less than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days). ATSDR presents these MRLs in Toxicological Profiles. These chemical-specific profiles provide information on health effects, environmental transport, human exposure, and regulatory status. In the following discussion, Toxicological Profiles for chlordane, dieldrin, and benzene hexachloride were referenced.

Chlordane

Past, present, and future exposure to chlordane is possible to adults and children who eat contaminated fish from the unnamed tributary. Since chlordane concentrations in fish were below USFDA 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 that residents consumed the U.S. daily intake (6.5 g/day) averaged over a year. Another assumption was that some residents receive all of their daily fish intake from the unnamed tributary which is most likely an overestimate of exposure to chlordane.

For adults and children, the estimated ingestion exposure dose did not exceed ATSDR's oral MRL (0.00006 mg/kg/day) for chronic exposure to chlordane. Because the level of exposure is so low, these people are likely not to experience harmful health effects. Furthermore, estimates of lifetime cancer risk indicate that insignificant or no increased risk of developing cancer over a lifetime exist for persons consuming the fish.

Exposure to chlordane has occurred and is occurring to persons who wade in the unnamed tributary and contact contaminated sediment. The amount of chlordane dermally absorbed from sediment 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 the chlordane contaminated sediment was absorbed through the skin into the body.

Estimates of lifetime cancer risk using 1987 sediment sampling data suggested a low increased risk of developing cancer over a lifetime for adults and no apparent increased risk of developing cancer over a lifetime for children. It was assumed that exposure to adults would be no more than 5 days per week for 25 weeks per year for a total of 30 years; additionally, children's exposure would be no more than l5 years. These assumptions err on the side of conservatism since water in the unnamed tributary may not exist during some warmer months of the year. More recent sediment sampling has shown that chlordane contaminated sediment has decreased and, hence, present and future exposure to chlordane contaminated sediment should also decrease. Based on the 1991 sediment sampling data, insignificant or no increased risk of developing cancer should occur from persons exposed to the chlordane-contaminated sediment.

Dieldrin

Dieldrin exposure through fish ingestion has occurred and is occurring in some residents who fish from 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 and children 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 who eat fish from the unnamed tributary. The same assumptions were made as in the two previous organochlorines. The estimated ingestion dose did not exceed ATSDR's oral MRL (0.00l mg/kg/day) for chronic exposure to beta-BHC. Lifetime excess cancer risk estimates for adults and children are insignificant. Future exposure to beta-BHC will decrease further as remedial activities have eliminated site sources of contamination from entering the unnamed tributary.

B. Health Outcome Data Evaluation

A 1986 health study was performed of the mortality experience of all VCC employees who had worked 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 this group of workers with US workers. Results showed a generally more favorable experience than US 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 experience among production workers, but not to a significant degree. It also determined that no unusual patterns were found among deaths due to reasons other than cardiovascular, cerebrovascular, or neoplasms. This study further confirmed results from previous studies that there was no significant health risk from long-standing exposure to the amounts of chlordane present in the work 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 exposure was limited to a small population. This small exposed population size would not provide any statistically significant data.

C. Community Health Concerns Evaluation

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 promote any chronic (long-term) health effects.

2. Does the eating of contaminated fish from the unnamed tributary cause a health concern?

Persons who consume or consumed fish from the unnamed tributary should not experience adverse 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 migrate into the unnamed tributary. However, this is currently not the situation since the unnamed tributary has been rechanneled and other remedial activities have contained and lessened contamination on-site.

Agency for Toxic Substances and Disease Registry, 1825 Century Blvd, Atlanta, GA 30345
Contact CDC: 800-232-4636 / TTY: 888-232-6348 

Department of Health and Human Services