PUBLIC HEALTH ASSESSMENT
DOWZER ELECTRIC
MT. VERNON, JEFFERSON COUNTY, ILLINOIS
The Dowzer Electric Company site is located on 4 acres at the southeastern edge of Mount Vernon
in Jefferson County, Illinois. Before removal actions were conducted at the site, on-site soils were
contaminated with polychlorinated biphenyls (PCBs), volatile organic compounds (VOCs), and total
recoverable petroleum hydrocarbons (TRPHs). Area groundwater exhibited isolated PCB and VOC
contamination. Off-site PCB contamination was identified in the sediment and aquatic biota 
of
Casey Fork Creek, which borders the eastern boundary of the Dowzer property. The results of the
findings of PCBs were reported in the news media, and community members voiced concerns about
the contamination at the Dowzer facility and Casey Fork Creek.
The Illinois Environmental Protection Agency (IEPA) collected soil samples from adjacent residences on Castleton Avenue directly north of the facility and analyzed the samples for PCBs. Of the 16 residential soil samples collected in 1985, two samples contained PCBs quantified at just above the laboratory detection limit of 5 parts per million (ppm).
In June 1988, a fire destroyed two warehouses at the Dowzer facility. Because of the fire, the facility owner immediately implemented clean-up operations, and clean-up continued until October 1991. The warehouse structures and PCB-contaminated soils were removed, and a storm sewer was removed and replaced. A nearby property owner was concerned that the fire had spread PCBs to his property. At the property owner's request, IEPA officials collected surface wipe and soil samples from the residential property and analyzed the samples for PCB contamination. No PCBs were found in those samples.
As part of the clean-up, a portion of Casey Fork Creek was permanently rerouted around the PCB contamination. Once sediment was remediated, the old creek bed was filled with clean backfill. In October 1995, IEPA collected surficial sediment samples from Casey Fork Creek adjacent to and downstream from the former Dowzer site. A maximum PCB concentration of 0.35 ppm was detected in the sample collected 0.9 miles downstream of the site. No one has expressed further concerns since the clean-up was completed.
Casey Fork Creek bounds the east side of the site and is a tributary of the Big Muddy River. The Big Muddy River was impounded south of Mount Vernon to form Rend Lake, which was created for flood control, for drinking water supplies, and for recreational use. Rend Lake is the source of public drinking water for approximately 55 communities, including the approximately 17,000 people who live in Mount Vernon. The water system distributes about 10 million gallons of treated water per day. PCBs have not been detected in surface water samples collected from Casey Fork Creek or Rend Lake. In addition to Rend Lake, the water supply for the city of Mount Vernon is supplemented by three reservoirs: Miller Lake, Lake Jaycee, and L & N Reservoir, all upstream of the Dowzer site.
The former Dowzer site poses no apparent public health hazard at this time. Much of the concern about the site has been eliminated with the clean-up action at the site and the remediation of the PCB contamination in Casey Fork Creek. PCB levels in fish were above comparison values in 1989 samples. We do not know what levels of PCBs may be currently present in fish tissue because no recent samples have been collected and analyzed. Therefore, consumption of PCB-contaminated fish remains a potential exposure pathway. Although low levels of PCBs continue to be detected in Casey Fork Creek sediment downstream of the site, little direct exposure to the contaminated sediment is likely because of limited access.
A. Site Description and History
The Dowzer Electric Company owned and operated a facility on approximately 4 acres at the corner of Castleton Avenue and First Street on the southeastern edge of Mount Vernon, Illinois in Jefferson County (Figure 1). The facility repaired and remanufactured transformers. In 1983, a "PCB destruct system" was installed at the facility. This system used sodium naphthalide to detoxify transformer fluids that contained PCBs. The facility operated from 1939 until approximately 1984 when operations were transferred to a new facility at Fountain Place Industrial Park, also in Mount Vernon. The original facility continued to operate the PCB destruct system, and the building continued to be used as a warehouse.
Casey Fork Creek bounds the east side of the Dowzer property. Since 1976, areas of and near Casey Fork Creek and the Dowzer facility have been studied for PCB contamination. Soil, stream sediments, surface water, storm water runoff, and fish flesh have all been sampled and analyzed for PCBs among other contaminants. PCBs were detected in storm water runoff samples collected by the Illinois Environmental Protection Agency (IEPA) in 1976 and 1977 at a storm drain outfall south of the Dowzer facility. IEPA conducted a 1977 survey and found elevated PCB levels in fish flesh and stream sediments in Casey Fork Creek. IEPA collected additional data in 1984 and 1985 on stream sediments and storm water runoff that implicated the Dowzer facility as an active source of PCBs in Casey Fork Creek.
In May 1985, IEPA notified Dowzer of the company's possible violations of the Illinois Environmental Protection Act and Rules and Regulations of the Illinois Pollution Control Board. As a result, Dowzer entered into a voluntary agreement with IEPA and began an investigation to determine the source of the PCBs. The company completed an initial Remedial Investigation/Feasibility Study (RI/FS) of the facility in December 1986.
Until 1988, facility structures consisted of two large warehouses, separated by a covered truck ramp, along the site's southern boundary. The warehouses were leased by Fairmont Industrial Supplies and contained stored drums of oils and cleaning supplies. A third, smaller building next to Castleton Avenue was used for truck maintenance. The PCB destruct facility structure, which consisted of the laboratory building and several covered aboveground tanks, was in the north-central portion of the property (Figure 2). The tanks on the property were in diked containment areas, so tank spills were contained. Water that collected in those areas during rainfalls was treated by a gravity separator and a charcoal filter system. In addition, the facility had a large concrete loading dock and an adjacent gravel parking lot along Casey Fork Creek.
In June 1988, a fire destroyed the two large warehouses and their contents. Because of the fire, Dowzer immediately implemented clean-up operations. Those operations consisted of the removal and disposal of the warehouse structures and part of the warehouse concrete flooring; excavation and removal of PCB-contaminated soil; and excavation, removal, and replacement of a storm sewer. The facility currently contains the PCB destruct laboratory building, the truck maintenance shop, the floor of the former warehouses, a loading dock, and a small shed. The rest of the area is covered by gravel. Although the PCB destruct facility continued to operate at this facility even after the fire, those operations were sporadic and were completely discontinued in 1990. In September 1989, the name of Dowzer Electric was changed to Hevi-Duty Electric. (For purposes of this report, the name Dowzer is used to refer to the site and its activities).
Site topography is generally flat with a slight eastward slope that allows most of the surface runoff from the facility to flow toward Casey Fork Creek. The geology beneath the site is described as fill material ranging from 0 to 8 feet thick, with the thickest portion near Casey Fork Creek (6). Below the fill are 10 to 15 feet of naturally occurring, clayey silt and clay soils. Beneath those soils is a zone of approximately 3 feet of highly weathered siltstone. Massive claystone with areas of sandstone and limestone in varying thicknesses is encountered below the weathered bedrock zone. Groundwater at the site is generally less than 10 feet from ground surface. Groundwater flows east toward Casey Fork Creek (6).
During the initial Remedial Investigation (RI) of the facility in 1986, PCB contamination was not found in surficial sediments of Casey Fork Creek. When the fire clean-up operations and replacement of the storm water sewer took place, however, a layer of black material was discovered beneath the surficial stream sediments of the creek near the storm water sewer outfall. To further determine the extent of the PCB contamination, Dowzer initiated a supplemental RI in 1989. The supplemental RI included further investigation of the creek, the sanitary sewer that traverses the Dowzer facility and the M & R property, the groundwater, and the soil on the M & R property.
Remediation of the known areas of PCB contamination along the stream banks and in Casey Fork Creek next to the Dowzer site were completed in October 1991. To remediate the contamination, a section of Casey Fork Creek was permanently rerouted eastward, around the PCB-contaminated areas. After the area was remediated, clean backfill was placed in the old creek bed.
On January 3, l990, Illinois Department of Public Health (IDPH) staff visited the site. At that time, the site appeared to be inactive. IDPH staff saw no employees at the facility. Although the initial phase of the clean-up had been completed at the time of the visit, the site was still posted with IEPA banner tape. The tape had been originally placed around the site boundary following the fire. The only buildings we saw on the site were the laboratory, the maintenance shop, and a small shed. The concrete floor was all that remained of the former warehouses. Access to this portion of the site was restricted only by the banner tape. A fenced and locked gate surrounded the graveled parking lot on the eastern boundary of the site along the Casey Fork Creek.
IDPH staff visited the site again on October 30, 1990 along with two IEPA representatives, a Dowzer employee, and several employees of Central States Environmental Services, Incorporated (CSES). CSES was the firm contracted to perform the final phase of the site clean-up associated with the Dowzer facility. The final phase of the clean-up included removal of known areas of PCB contamination along the stream bank and stream sediment in that portion of Casey Fork Creek next to the Dowzer site, particularly at the outfall of the storm sewer. The creek was to be permanently rerouted, which was the best option to address the contamination, around the area of gross PCB contamination.
At the time of the visit, the creek had already been rerouted, and excavation of the old creek bed was in progress. After the soil was excavated, it was stockpiled on plastic on the concrete floor of the former Dowzer warehouse. The stockpiles were then sampled and identified as to PCB content for proper disposal.
Most recently, IDPH staff visited the site on December 1, 1995. All remediation activities at the site had been completed, and the site remained abandoned. No further site visits are necessary until decisions are made as to whether additional work will be done at the site.
C. Demographics, Land Use, and Natural Resource Use
The Dowzer site is situated on 4 acres on the southeastern edge of the city of Mount Vernon in Jefferson County, Illinois. Mount Vernon is populated by approximately 17,000 people (14). Casey Fork Creek bounds the east side of the site; the M & R Company bounds the south side. Open industrial land bounds the west side; and residential properties bound the north side. Approximately 600 people live in neighborhoods next to the facility. The nearest school to the site is Mount Vernon Township High School, which is approximately 0.5 miles northwest of the site at the intersection of 7th Street and Casey Avenue. No hospitals or long-term care facilities are near the site.
Casey Fork Creek, which flows south along the eastern edge of the facility, is a small stream with
high flows generally observed in the spring and after rainfall. Portions of the creek near the site are
intermittent between rainfalls. Access to the creek near the site is limited. The main channel of
Casey Fork Creek is approximately 27 miles long (6). Casey Fork has a total drainage area of
116.2 square miles (6). Land use in the Casey Fork drainage basin includes undeveloped woodland
areas, cultivated farmlands, and urban areas. Seven permitted wastewater dischargers are in the
Casey Fork drainage basin (Figure 3). The Mount Vernon Sewage Treatment Plant, one of the
permitted dischargers, is immediately downstream of the Dowzer facility. Four impoundments are
in the Casey Fork drainage basin: 1) Miller Lake; 2) Lake Jaycee; 3) L & N Reservoir; and 4)
Casey Fork impoundment of Rend Lake. The first three of these impoundments are supplemental
water supply reservoirs for the city of Mount Vernon and are upstream of the Dowzer site. The
Casey Fork impoundment is on the northern tip of Rend Lake. It is used by the Illinois Department
of Natural Resources to provide increased waterfowl habitats during the fall and winter months.
The headwaters of the impoundment are approximately 12 miles downstream of the Dowzer site (5).
Casey Fork Creek is a tributary of Rend Lake and the Big Muddy River. The Big Muddy River drains into the Mississippi River approximately 120 miles downstream of Rend Lake. Rend Lake, in Jefferson and Franklin Counties, is a man-made reservoir created in 1970 by damming the Big Muddy River. In addition to the Big Muddy River and Casey Fork Creek, major tributaries to the lake include Atchison Creek, Gun Creek, and Rayse Creek (10). The surface area of Rend Lake is 18,900 acres with a total drainage area of 488 square miles (10). The northernmost portion of the lake is approximately 17 miles downstream of the Dowzer site. Besides the city of Mount Vernon, approximately 10 other small communities are within the Rend Lake watershed. Land in this watershed is used primarily for crops and pastures. Land in the area is also used for residences, industry, and undeveloped woodland. Additionally, many small oil wells are located throughout the area.
Rend Lake was created to provide flood control and community water supplies. It serves as a source of drinking water for about 55 communities. Water treatment facilities managed by the Rend Lake Intercity Water System treat and distribute approximately 10 million gallons of water per day (10). The lake is also used for recreational activities including boating, swimming, fishing, and wildlife management.
We can use state health databases to evaluate whether certain health effects are higher than expected in a particular area, such as an exposed population near a hazardous waste site (1). This section lists available databases; a discussion of whether the information can be used to evaluate conditions at this site appears in the Public Health Implications section of this document.
In Illinois, the Health and Hazardous Substances Registry Act was signed into law in 1984. Because of the Act, the Health and Hazardous Substances Registry (IHHSR) was created. Primarily, the IHHSR is designed to monitor health effects among the citizens of Illinois related to exposures to hazardous substances in the work place and in the environment. Specifically, the IHHSR is a unified statewide project that allows collection, compilation, and correlation of information on public health and hazardous substances. The registry contains information about the following categories:
The Illinois State Cancer Registry (ISCR) is one of the registries developed as a result of this Act. As of January 1, 1985, all newly diagnosed cancer patients in non-federal Illinois hospitals are reported to ISCR. In addition, some federal hospitals in Illinois report cases voluntarily. Some bordering states also exchange cancer data with Illinois (16). The ISCR is the prime source for information on cancer incidence within the state. Currently, the ISCR includes cancer incidence data for the years 1985-1995.
People in the community voiced concerns about the PCB contamination at the Dowzer site and in Casey Fork Creek. Most of the concerns followed local newspaper coverage about PCBs. Early reports about PCB-contaminated fish in Casey Fork Creek roused significant attention from the community. Individuals also expressed concern about children playing in Casey Fork Creek and in neighborhoods near the Dowzer site and about the effect of PCBs on the water quality of Rend Lake and drinking water supplied by Rend Lake.
Fears regarding PCBs at the Dowzer site were again expressed following the fire at the Dowzer warehouse in June 1988. IEPA conducted residential soil and wipe sampling at that time in an attempt to address some of the questions from people living next to Dowzer property. IEPA collected a surface wipe sample from a soot-damaged automobile at a residence north of the Dowzer site and a soil sample from a garden area at the same residence. The samples were analyzed for PCBs, dioxins, and furans; no contaminants were detected.
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
The tables in this section list contaminants selected and discussed based upon the following factors (1):
In the data tables presented in the On-site Contamination and Off-site Contamination subsections, a contaminant is listed if the amount of the contaminant is present in an environmental medium at a level greater than a comparison value for that medium. The list indicates which contaminants are evaluated further to determine if people are actually exposed to the contaminant and if so, whether that exposure can affect the health of those exposed.
The data tables include the following acronyms:
* CREG = Cancer Risk Evaluation Guide
* EMEG = Environmental Media Evaluation Guide
* RMEG = Reference Dose Media Evaluation Guide
* MCLG = Maximum Contaminant Level Goal
* MCL = Maximum Contaminant Level
* PMCLG = Proposed Maximum Contaminant level Goal
* ppm = parts per million
* ppb = parts per billion
* RfD = Reference Dose
* RfC = Reference Concentration
Comparison values, which are contaminant concentrations in specific environmental media, include Environmental Media Evaluation Guides (EMEGs), Reference Dose Media Evaluation Guide, Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. EMEGs, RMEGs, and CREGs are estimated contaminant concentrations derived from health screening values developed either by ATSDR or USEPA.
The USEPA's Maximum Contaminant Level Goal (MCLG) is a drinking water health goal. USEPA believes that the MCLG represents a level that poses no known or anticipated adverse health effect to people exposed to the contaminant. Proposed Maximum Contaminant Level Goals (PMCLGs) are MCLGs that are proposed but have not yet been officially accepted as MCLGs.
Maximum Contaminant Levels (MCLs) represent contaminant concentrations that USEPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime's (70 years) exposure at an ingestion rate of 2 liters water per day. While MCLs are regulatory concentrations for public drinking water supplies, PMCLGs and MCLGs are not.
Before the initial clean-up following the fire in 1989, on-site contamination included PCBs and VOCs. The primary VOCs found were 1,1,1-trichloroethane, chlorobenzene, xylene, carbon tetrachloride, 1,1-dichloroethene, and toluene. PCBs were detected in the soil and the groundwater. Wall surface wipe samples collected on portions of the former warehouse also contained PCBs. VOCs were detected in the soil and groundwater; however, the VOC contamination appeared to be concentrated near monitoring wells #5 (MW-5) and #9 (MW-9) (Figure 4).
The clean-up initiated because of the fire on site involved removing the warehouse structures and PCB-contaminated soil. A storm sewer was also removed and replaced. Additionally, MW-5 and the contaminated soil surrounding it were removed. MW-9 was left in place; however, the contaminated soil surrounding it was excavated.
Soil
IEPA collected surface soil samples (3-4 inches deep) in 1984 that contained PCB concentrations ranging from 0.01 to 132 ppm (5). Most of the surface soil samples were collected on Dowzer property at the graveled lot next to Casey Fork. Subsurface soil contained PCBs at levels that ranged from less than detectable to 510 ppm, with the highest levels found in samples collected from a depth of 0 to 2 feet near MW-5 (5). PCBs were detected in 15 of the 62 samples collected in 1986.
Four out of 17 soil samples contained VOCs. The VOCs detected included chlorobenzene, 1,1,1-trichloroethane, and total xylenes. The VOC present at the highest level was 1,1,1-trichloroethane in the subsurface soil near MW-9 (5). All values represent what was present prior to site clean-up, and none of the VOCs found exceeded comparison values.
Table 1. Range of Contaminant Concentrations in On-site Soils
|
Concentration Range (ppm) |
Comparison Value (ppm)/Source |
||
| PCBs (0-4 inches) |
0.4/CREG | ||
| PCBs (0-24 inches) |
0.4/CREG |
CREG = Cancer Risk Evaluation Guide
ND = Not Detected
Groundwater
PCB contamination present in the groundwater in 1985 ranged from less than detectable to 6.5 ppm (5). The highest level of PCBs present in the groundwater was found in MW-5, which was in the area that contained VOC contamination.
Groundwater was not thoroughly investigated and characterized during the original Remedial Investigation (RI); therefore, the extent of groundwater contamination was not known when the site was cleaned following the fire. Table 2 presents what contamination was found prior to the clean-up effort. Upon further investigation during the clean up, VOCs were also found near MW-9, approximately 50 feet west of MW-5.
Table 2. Maximum Contaminant Concentration Detected in On-site Groundwater (MW-5), Dowzer Site (Pre-Remediation - 1985)
|
CONTAMINANT |
Concentration (ppb) |
Comparison Value (ppb)/Source |
| PCBs |
0.02/CREG | |
| methylene chloride |
5.0/CREG | |
| 1,1-dichloroethane |
NA/Cancer Group C* | |
| carbon tetrachloride |
0.3/CREG | |
| tetrachloroethylene |
0.7/CREG | |
| toluene |
200/iEMEG | |
| 1,1-dichloroethene |
0.06/CREG | |
| 1,2-dichloroethene (trans) |
100/LTHA | |
| 1,2-dichloroethane |
0.4/CREG | |
| 1,1,1-trichloroethane |
200/LTHA | |
| 1,1,2-trichloroethane |
0.6/CREG | |
| chlorobenzene (MW-9) |
100/LTHA |
CREG = Cancer Risk Evaluation Guide
NA = No comparison value available
Cancer Group C = Possible carcinogen, but no human data
and limited animal data available for evaluation
iEMEG = Intermediate Environmental Evaluation Guide
LTHA = Lifetime Health Advisory
Because of the additional contamination found during the initial clean-up, supplemental RI field activities were conducted at the Dowzer facility in June 1989. Additional monitoring wells were installed on-site to expand the existing monitoring well network. Groundwater samples collected during the supplemental RI did not contain PCBs, and total VOCs were present at levels less than detectable to 2.81 ppm (6).
Warehouse
Wipe samples were collected from visibly stained wall surfaces in the warehouse. The samples with the highest levels of PCBs were collected from the exterior wall surfaces of the eastern warehouse (5). The brick surface of the warehouse where samples were collected appeared oil stained. The structure itself was composed of a concrete foundation, over which an approximately 6-inch-thick slab floor had been constructed. Construction-grade cinder blocks formed the walls of the structure. The samples were collected before fire destroyed the warehouse.
Storm Sewer
A storm sewer, which received storm water discharge from upgradient sources, ran along the gravel roadway, immediately south of the Dowzer facility. Water generally flowed through the storm sewer only when precipitation generated water. The storm drain received discharge and runoff from surrounding areas and discharged the storm water directly into Casey Fork Creek. To determine the source of PCBs in Casey Fork Creek sediments, the storm drain system was sampled in 1985. Water and sediment samples were taken at several locations within the main storm drain system. A sample of a non-aqueous fluid (oil) was collected from the south outfall. The oil sample contained PCBs at 14,000 ppm. Levels of PCBs in the sediment samples ranged from less than detectable to 7.8 ppm, while PCB concentrations in the water discharge samples ranged from less than detectable to 37.0 ppm.
The storm water discharge contained 6.5 ppm total VOCs. The storm water was tested for the presence of 34 VOCs. A total of six VOCs were found in the water at measurable levels (Table 3). No comparison values exist for storm water discharge.
The contaminated storm sewer was removed and replaced during the clean-up operations in 1988. Because the storm sewer was remediated, that area was not included in further investigations conducted during the supplemental RI.
Table 3. Summary of Contaminants Detected in Storm Water Discharge
Dowzer Electric Site (Pre-Remediation, 1986).
| Contamination | |
| PCBs | |
| 1,1-dichloroethene | |
| methylene chloride | |
| carbon tetrachloride | |
| benzene | |
| 1,1-dichloroethane | |
| 1,1,1-trichloroethane |
Sanitary Sewer
A Mount Vernon sanitary sewer runs in a north-south direction beneath the Dowzer facility. The sewer then passes under the adjacent M & R property and runs approximately 1/2 mile downgradient to the Mount Vernon Sewage Treatment Plant. Initial measurements of PCBs in the sanitary sewer line near the Dowzer facility were performed in 1985. PCB concentrations ranged from below the level of detection to 0.0056 ppm in water samples. The contamination appeared to be entering the sanitary sewer line near the location that the sanitary sewer crossed the storm sewer. Sanitary sewer sediment sample results did not indicate PCB concentrations present above the laboratory detection limit of 1.0 ppm.
VOC analysis of sanitary sewer water samples (1986) showed the presence of total VOC concentrations ranging from 0.012-0.355 ppm. Chloroform, tetrachloroethene, and acetone were the only VOCs detected. Acetone (a common laboratory contaminant) was the VOC present at the highest concentration (0.29 ppm).
During the Supplemental RI, three samples were collected from the sanitary sewer line bedding (Figure 5). Each sample was analyzed for PCBs, VOCs, and total recoverable petroleum hydrocarbons (TRPHs). PCB levels ranged from less than detectable to 182 ppm with the highest level present in the sample collected at the point where the sanitary sewer crosses the storm sewer. Total VOCs were detected at a range of 0.159-7.31 ppm. The highest VOC concentration was detected in the sample collected near the former eastern warehouse. A source of VOCs was discovered beneath the former warehouse during the clean-up. TRPHs were detected at a range of less than detectable to 1,930 ppm. The sample containing the highest level of TRPHs was also the sample in the sanitary sewer that contained the highest level of PCB contamination.
M & R Property
During the Supplemental RI, soil borings and test pits were sampled on the M & R property that borders the southern boundary of the Dowzer site. The samples were analyzed for PCBs, VOCs, and TRPHs. That sampling was conducted to determine if site-related contamination was on that property. During the clean-up activities, a "black layer" was identified within a few feet of the ground surface along the southern face of the storm sewer trench between the M & R property and the Dowzer site. The nature and extent of the contamination was not determined during the clean-up activities.
PCB concentrations in the soil ranged from less than detectable to 0.573 ppm. VOC concentrations ranged from less than detectable to 0.108 ppm, and TRPH concentrations ranged from less than detectable to 5,280 ppm. PCB concentrations in the test pits ranged from less than detectable to 33.7 ppm. The PCB contamination appeared to be limited to the "black layer" along the storm sewer. The TRPHs detected in the surface soil were attributed to M & R employee parking areas and the prior location of an aboveground storage tank (6).
Casey Fork Creek
Both fish and sediment samples were collected from Casey Fork Creek and were analyzed for PCB contamination as early as 1977. Initial investigations of the creek indicated PCB contamination was not present in the surficial sediments downstream of the Dowzer site. During the fire clean-up operations, however, gross PCB contamination of the creek was discovered. That discovery initiated the Supplemental RI.
a. Sediment
Sediment samples were collected from the gravel bar next to the Dowzer facility and the creek channel in 1989. Samples were collected from 1 and 3 foot depths at nine locations within the gravel bar (Figure 6). Fine sediment in the creek channel was collected both downstream and upstream of the facility at 17 locations (Figure 7). The gravel bar samples contained PCBs at concentrations ranging from 0.01 to 3,250 ppm. Four samples had concentrations greater than 100 ppm. The greatest concentrations were detected in samples collected just beyond the end of the storm sewer discharge pipe. The PCB concentrations generally decreased in samples collected downstream of the outfall. These data indicated the storm sewer outfall may have been the conduit by which PCBs entered Casey Fork Creek. Fine sediment samples contained PCB levels ranging from 0.007 to 5.22 ppm. The purpose of sampling the fine sediment was to determine if PCB contamination was below the surficial stream deposits (below 6 inches). In general, the fine sediment samples collected upstream of Dowzer did not contain detectable levels of PCBs. Samples collected near the site and within 1/2 mile downstream contained PCBs ranging from 1.42 to 5.22 ppm. Samples collected 3/4 of a mile and further downstream did not contain detectable levels of PCBs.
IEPA representatives collected sediment samples from Casey Fork Creek for PCB analysis in October 1995. The sample collected upstream of Dowzer did not contain detectable levels of PCBs. Samples collected near the site and within 0.9 miles downstream contained PCBs ranging from 0.09 to 0.35 ppm.
Stream sediment samples were collected in 1986 for analysis of VOCs. Two sediment samples were collected: one upstream and one downstream of the Dowzer facility. Results indicated that benzene (0.40 ppm) was the only VOC detected in the upstream sample. No VOCs were detected in the downstream sample. Additional sampling for VOCs in the sediment was not conducted during the Supplemental RI.
b. Aquatic Biota
Before the Supplemental RI, fish were collected in Casey Fork Creek and the Casey Fork Creek impoundment of Rend Lake in 1977, 1984, 1985 and 1986 for the analysis of PCB contamination (Table 4). The variety of fish collected included carp, bigmouth buffalo, largemouth bass, crappie, black bullhead, and bluegill. PCBs were detected in all fish sampled in 1977. One carp sample had a PCB concentration greater than 6 ppm, several carp and bigmouth buffalo contained PCB concentrations greater than 2 ppm, and most samples contained PCB concentrations greater than 1 ppm. The 1977 data, however, were from whole fish samples rather than edible portions only. The samples from 1984, 1985, and 1986 generally contained less than 2 ppm with most less than 1 ppm, except for one 1986 composite fish sample that had a concentration of 14 ppm.
Table 4. Range of PCB-1260 Detected in Fish Species Collected from Casey Fork Creek Downstream of Dowzer Electric Site
ND = Not Detected
During the Supplemental RI, fish, including sunfish, largemouth bass, creek chubsucker, bullhead, and carp, were sampled at five stations in Casey Fork Creek, and the edible portions were analyzed for PCBs. All fish samples analyzed contained levels of PCBs, some with levels above the U.S. Food and Drug Administration (USFDA) tolerance value of 2 ppm (Table 5). The highest concentration (17.5 ppm) was found in a bullhead sample collected at the station near the gravel bar where elevated levels of contamination were also detected in the sediment. A sunfish sample also collected at that location contained 9.9 ppm PCBs. The PCB concentrations in the fish tissue generally declined with downstream distance from the facility.
Besides fish samples, benthic invertebrates were collected in 1989 from riffle and pool habitats at three locations in the creek. A composite sample was collected from each of the pooled locations and analyzed for PCBs. PCBs were detected in all three samples at concentrations ranging from 1.47 to 3.46 ppm.
Fish samples were analyzed for VOC contamination in 1986. The only VOCs detected were methylene chloride at 3.0 ppm and pentane at 25 ppm, both in the same sample from the sampling station nearest the Dowzer facility. Although the source of the pentane was unknown, the occurrence of methylene chloride was attributed to laboratory contamination. No additional VOC analysis of fish samples was conducted during the Supplemental RI.
Table 5. Fish Monitoring Data Summary - Casey Fork Creek (1989)
|
PCB Concentration Range (ppm) |
||
| Sunfish | ||
| Large Mouth Bass | ||
| Creek Chubsucker | ||
| Bullhead | ||
| Common Carp | ||
| Benthic |
Source: Hunter/ESE, 1989.
c. Surface Water
Surface water samples from Casey Fork Creek have been collected in the past for both PCB and VOC analysis. The most recent sampling was conducted in 1986. No PCBs or VOCs were detected in any of the surface water samples.
Rend Lake
In 1976, an intensive study of Casey Fork Creek was conducted by the Illinois State Water Survey (ISWS) as part of their study on Rend Lake and its tributaries. The ISWS study was an extensive study effort that included surveys of the stream sediments and aquatic ecology. The water quality effort focused principally on traditional water quality parameters and a few heavy metals. There were no measurements for organic contaminants. The results of this study indicated that the water quality of Casey Fork Creek upstream of Mount Vernon was generally acceptable, whereas the water quality downstream of Mount Vernon was often poor with low concentrations of dissolved oxygen and elevated values of phosphate, nitrogen species, coliform and some metals (10). Generally, the water quality in Casey Fork Creek reflected the effects of discharges to the creek and land use within the drainage basin. The water quality change reflected the change in land use from rural and lesser populated areas north of Mount Vernon to the more densely populated and industrialized area of the city itself (10). The ISWS concluded that the general poor water quality of Casey Fork Creek limited its ability to provide a suitable environment to support a fishery (10).
The input of Casey Fork Creek to Rend Lake did not appear to have adversely compromised the water quality of the lake itself. The water quality of Rend Lake was reported as generally good with only occasional occurrences of low dissolved oxygen at deeper levels within the lake (10).
Soil
In the past, several off-site soil samples have been collected from various properties next to the Dowzer site in an attempt to determine if there had been off-site contamination with PCBs (Figure 8). IEPA collected two soil samples in 1981 at locations identified 200 feet northeast and 200 feet north of the Dowzer site. Results of that sampling effort identified PCB levels present at 7.7 and 2.3 ppm. The depth of the samples was not provided. IEPA collected additional residential soil samples in October 1985. PCB levels in those samples ranged from below the detection limit to 6.0 ppm. Only 2 of the 16 samples contained levels above the detection limit of 5.0 ppm (5.0 and 6.0 ppm) and both were collected at a depth of 1 inch.
Seven off-site soil samples were collected in October 1985, along the eastern bank of Casey Fork Creek. At each location, a surface sample to a depth of 1 inch and composite sample from a depth of 1 to 12 inches were collected. Only one sample (collected at the 1-12 inches depth) contained PCBs at levels above the detection limit of 1.0 ppm. A PCB concentration of 15.0 ppm was detected in this sample while a field duplicate of this sample contained a PCB concentration of 4.5 ppm.
In 1988, residential sampling was conducted to determine if PCBs or related contaminants were carried off-site because of the fire and smoke. IEPA collected a surface wipe sample from a soot-damaged automobile at a residence north of the Dowzer site and a soil sample from a garden area at the same residence. The samples were analyzed for PCBs, dioxins, and furans, none of which were above the detection levels. No further residential off-site sampling was conducted during the Supplemental RI.
C. Quality Assurance and Quality Control
In preparing this public health assessment, IDPH relied on the information provided in the referenced documents. IDPH assumed 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 analyses and conclusions drawn for this public health assessment are determined by the availability and reliability of the referenced information.
Discussion in the Supplemental RI report indicated the data contained therein had undergone quality assurance review. IDPH noted in the report that acetone was detected in nearly every soil and groundwater sample analyzed for VOCs, including the field blanks. Isopropanol was the decontamination solvent used during field activity, and evaluation of the analysis results showed a direct correlation between the concentration of acetone and the presence of isopropanol. IDPH believes that the presence of acetone in both the soil and groundwater samples is an artifact of the use of isopropanol during the decontamination of sampling equipment. The occurrence of acetone in the samples should be evaluated appropriately.
The Dowzer facility currently contains two buildings: a small laboratory/office and a maintenance garage. The buildings were previously used in a limited capacity for repairing trucks and laboratory analysis. When not in use, the buildings remain locked at all times. Additional structures on the site include part of the concrete floor of the former Dowzer warehouse, a loading dock, and a small shed. The rest of the area is covered by gravel. A gravel parking area located next to Casey Fork Creek is surrounded by a locked chain-link fence. Although current activities at the site are limited, the site has not been completely abandoned. Evidence from the last site visit indicates no physical hazards appear to be associated with the Dowzer site.
To determine whether nearby residents are exposed to contaminants migrating from the site, the environmental and human components that lead to human exposure are evaluated. An exposure pathway consists of five elements: a source of contamination; transport of the contamination through an environmental medium; a point of exposure; a route of human exposure; and an exposed population (16).
IDPH categorizes an exposure pathway as a completed or potential exposure pathway if the exposure pathway cannot be eliminated. In a completed exposure pathway, the five elements are present. The exposure to the contaminant has occurred in the past, is occurring, or will occur in the future. Potential pathways, however, include pathways that have at least one of the five elements missing, but data are not available to verify the element exists. Potential pathways indicate exposure to a contaminant could have occurred in the past, could be occurring, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present (16).
Currently, no completed pathways have been associated with the site. The potential human exposure pathways to site contaminants include ingestion, inhalation, or dermal absorption of contaminants in groundwater, surface water, and soil or dust. Additional potential pathways include ingestion of contaminated food stuffs (primarily fish), inhalation of fugitive volatile air emissions and dermal absorption of stream sediments.
As previously discussed, groundwater use in the area is minimal. The surficial aquifer, which exhibited contamination with site constituents, does not have sufficient thickness to provide an adequate water supply, and no site constituents appeared to have migrated from the shallow groundwater into the bedrock. No residential wells were identified downgradient of the Dowzer site. Most of the surrounding community is serviced by a municipal water supply district that obtains water from Rend Lake. Therefore, exposure to contaminants in groundwater through ingestion of drinking water, dermal contact and absorption, and inhalation of aerosolized or volatilized contaminants during showering or other household activities are unlikely.
The groundwater does, however, flow toward Casey Fork Creek. Besides groundwater recharge, Casey Fork Creek receives surface run-off from the site. Approximately 17 miles downstream of the Dowzer site, Casey Fork Creek empties into Rend Lake which serves as a public water supply for 55 communities. Surface water samples of Casey Fork Creek did not contain detectable levels of any of the contaminants associated with the site. In water, adsorption to sediments or other organic matter is a major fate process for PCBs rather than remaining in the water column. VOCs are generally not found in surface water because they tend to evaporate from water open to the air. Thus, exposure to site contaminants through ingestion, inhalation, and dermal absorption from using Rend Lake water for household purposes is also unlikely.
As indicated previously, the major fate process of PCBs in water is adsorption to sediments. Extensive PCB contamination of Casey Fork Creek sediments was identified, particularly near the Dowzer site. Exposure through direct dermal contact with contaminated sediments in the creek from activities such as wading or swimming could have occurred, but no one is expected come in contact with that specific area of the creek for long periods of time because the area is not easily accessible.
Results for biological samples collected from the creek indicate PCBs have been taken up by aquatic organisms inhabiting the stream. Ingestion of the aquatic biota (fish, crayfish) caught out of the impacted waterways or of other animals that may feed or drink from these waters may result in exposure. We do not know if anyone is fishing in areas where the fish and invertebrates were shown to contain PCBs.
Inhalation, ingestion, and dermal contact from fugitive dusts transported off-site to the surrounding population are also potential routes of exposure. Normal activities and traffic on-site, however, are minimal. In addition, most of the contaminated surface soil has been remediated, thus minimizing the possibility of exposure to contaminated dust.
As discussed in the Environmental Contamination and Other Hazards and the Pathways Analyses Sections, the primary contaminant of concern is PCBs. The most likely exposure scenario to occur would involve individuals using Casey Fork Creek for fishing. These individuals may be exposed to PCBs through ingestion of contaminated fish or other aquatic biota such as crayfish. Some dermal absorption of contaminated sediments may occur if people also wade in the creek. PCBs have been the subject of a Toxicological Profile developed by the Agency for Toxic Substances and Disease Registry (ATSDR).
PCBs are very persistent environmental contaminants comprised of a family of man-made chemicals that contain 209 individual compounds (2). The environmental persistence of PCBs generally increases with an increase in the degree of chlorination. The higher the chlorination of a compound, the more resistant to biodegradation. PCB-1260, the only representative of the PCB family identified at the Dowzer site, is a highly chlorinated representative and is resistant to biodegradation.
The general population is primarily exposed to PCBs through the ingestion of food items, particularly fish. The contamination of fish is a consequence of the contamination of the aquatic environment and resulting bioconcentration. PCBs have poor solubility in water but good solubility in organic materials such as fats, and therefore, tend to accumulate in fat-rich tissue in animals. To reduce the risk of exposure from eating fish, the fat-soluble PCB contamination can be reduced by removing the skin and any fatty tissue beneath the skin near the belly or dorsal area of a large fish. Additionally, the fish should be broiled or baked on an elevated rack that will allow the fat to drip away from the finished meal.
In humans, PCBs tend to accumulate in adipose tissue, blood, and breast milk. Heavily chlorinated representatives redistribute to adipose tissue to a greater extent than the less chlorinated ones (2). Because PCBs do bioaccumulate, chronic exposure is a concern. Nursing infants may be exposed to high PCB concentrations in the breast milk of lactating mothers if the mothers consume large amounts of contaminated fish. Because PCBs can concentrate in milk, pregnant women or women who may become pregnant are also a population of concern. A number of studies indicate that PCBs can cross the placenta and locate in the fetus. Embryos, fetuses, and infants are potentially susceptible because they generally lack the enzyme systems that facilitate detoxification and excretion of PCBs (2).
Birth weight, head circumference, and gestational age were observed to be slightly decreased in newborns of mothers who were consumers of fish (2). Other studies found that consumption of PCB-contaminated fish by mothers and serum cord levels of PCBs were predictors of impaired development and abnormal reflexes in infants. These studies were not conclusive, however, because no specific doses of PCBs consumed by the mothers were determined (2).
Humans exposed to PCBs in the workplace reported adverse health effects including chloracne (acne-like lesions/rashes) and impairment of liver function. Workers generally experience PCB exposures that are much higher than those received by the general public. In the United States, acute adverse health effects such as those previously described have not been observed in people with nonoccupational exposure. In Japan, serious health effects were observed in individuals who consumed rice oil contaminated with substantial amounts of PCBs. The rice oil was contaminated, however, with PCBs called Kaneclors produced in Japan. These PCBs differ from the mixtures produced in the United States in that they have different chlorine content and a greater percentage of toxic impurities with reported higher effect levels than the mixtures produced in the United States (2).
Feeding studies in laboratory animals demonstrated the carcinogenicity of several PCB mixtures, although it is not clear which components of the mixture or metabolites are actually carcinogenic. In the studies, the liver was the primary target of the PCB carcinogenicity. Although data regarding the carcinogenicity of PCBs in humans is inadequate, PCBs are considered probable human carcinogens based on the animal data (2).
B. Health Outcome Data Evaluation
There was no site specific health outcome data identified or generated that was appropriate for this site. The study population associated with this site is too small for a relevant cancer incidence evaluation. Cancer incidence information for Jefferson County as a whole would not truly reflect any occurrence related only to the site.
C. Community Health Concerns Evaluation
As stated previously, concerns had been voiced regarding the PCB contamination at the Dowzer site and in Casey Fork Creek. In response to concerns of PCB contamination following the fire at the Dowzer site, IEPA collected surface wipe samples and soil samples at surrounding residential properties. The samples were analyzed for PCBs, dioxins, and furans, none of which were present above the detection levels.
After the removal action at the site and Casey Fork Creek, the concerns of the surrounding population were alleviated. No additional concerns have been expressed.
On the basis of the information reviewed, IDPH concludes the former Dowzer site poses no apparent public health hazard at this time. Much of the concern about the site has been eliminated with the clean-up action at the site and the remediation of the PCB contamination in Casey Fork Creek. Although levels of PCBs continue to be detected in Casey Fork Creek sediment downstream of the site, any exposure to the contamination would most likely be limited. Portions of Casey Fork Creek next to and downstream from the Dowzer site typically have low flow rates, except in spring and after rainfall, and become intermittent during periods of low rainfall. Creek access is limited in these areas. Those factors would generally make this portion of the creek unattractive for recreational use such as wading, swimming, and fishing. No other potential exposure pathways were identified that would likely result in exposure to site-related contaminants.
The surrounding community voiced concerns in the past regarding the PCB contamination at the Dowzer site, particularly the reports of PCB contamination of fish in Casey Fork Creek. The concerns were alleviated following the removal action at the site and the clean-up of Casey Fork Creek.
PREPARER AND REVIEWERS OF REPORT
Preparer of Report:
Lynn M. Stone
Environmental Toxicologist
Illinois Department of Public Health
Reviewers of Report:
Bruce C. Barrow
Ken Runkle
Environmental Toxicologists
Illinois Department Of Public HealthGail Godfrey
Steve Inserra
Grant Baldwin
Technical Project Officers
ATSDR
Atlanta, Georgia
Figure 3. Permitted Wastewater Discharges in the Casey Fork Drainage Basin
Figure 4. Areas of Contamination
Figure 5. Sanitary Sewer Line Analytical Results (mg/kg)
Figure 6. Casey Fork Creek Gravel Bar Sampling Locations
Figure 7. Location of Biological and Fine Sediment Sampling Sites in Casey Fork Creek
Figure 8. Off-Site Soil Sample Locations
