PUBLIC HEALTH ASSESSMENT
MT. VERNON, JEFFERSON COUNTY, ILLINOIS
The Dowzer Electric Company site is located on 4 acres at the southeastern edge of Mount Vernonin Jefferson County, Illinois. Before removal actions were conducted at the site, on-site soils werecontaminated with polychlorinated biphenyls (PCBs), volatile organic compounds (VOCs), and totalrecoverable petroleum hydrocarbons (TRPHs). Area groundwater exhibited isolated PCB and VOCcontamination. Off-site PCB contamination was identified in the sediment and aquatic biota ofCasey Fork Creek, which borders the eastern boundary of the Dowzer property. The results of thefindings of PCBs were reported in the news media, and community members voiced concerns aboutthe contamination at the Dowzer facility and Casey Fork Creek.
The Illinois Environmental Protection Agency (IEPA) collected soil samples from adjacentresidences on Castleton Avenue directly north of the facility and analyzed the samples for PCBs. Ofthe 16 residential soil samples collected in 1985, two samples contained PCBs quantified at justabove 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, thefacility owner immediately implemented clean-up operations, and clean-up continued until October1991. The warehouse structures and PCB-contaminated soils were removed, and a storm sewer wasremoved and replaced. A nearby property owner was concerned that the fire had spread PCBs to hisproperty. At the property owner's request, IEPA officials collected surface wipe and soil samplesfrom the residential property and analyzed the samples for PCB contamination. No PCBs werefound in those samples.
As part of the clean-up, a portion of Casey Fork Creek was permanently rerouted around the PCBcontamination. Once sediment was remediated, the old creek bed was filled with clean backfill. InOctober 1995, IEPA collected surficial sediment samples from Casey Fork Creek adjacent to anddownstream from the former Dowzer site. A maximum PCB concentration of 0.35 ppm wasdetected in the sample collected 0.9 miles downstream of the site. No one has expressed furtherconcerns 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. TheBig Muddy River was impounded south of Mount Vernon to form Rend Lake, which was createdfor flood control, for drinking water supplies, and for recreational use. Rend Lake is the source ofpublic drinking water for approximately 55 communities, including the approximately 17,000people who live in Mount Vernon. The water system distributes about 10 million gallons of treatedwater per day. PCBs have not been detected in surface water samples collected from Casey ForkCreek or Rend Lake. In addition to Rend Lake, the water supply for the city of Mount Vernon issupplemented by three reservoirs: Miller Lake, Lake Jaycee, and L & N Reservoir, all upstream ofthe Dowzer site.
The former Dowzer site poses no apparent public health hazard at this time. Much of the concernabout the site has been eliminated with the clean-up action at the site and the remediation of the PCBcontamination in Casey Fork Creek. PCB levels in fish were above comparison values in 1989samples. We do not know what levels of PCBs may be currently present in fish tissue because norecent samples have been collected and analyzed. Therefore, consumption of PCB-contaminatedfish remains a potential exposure pathway. Although low levels of PCBs continue to be detected inCasey Fork Creek sediment downstream of the site, little direct exposure to the contaminated sediment is likely because of limited access.
The Dowzer Electric Company owned and operated a facility on approximately 4 acres at the cornerof Castleton Avenue and First Street on the southeastern edge of Mount Vernon, Illinois in JeffersonCounty (Figure 1). The facility repaired and remanufactured transformers. In 1983, a "PCBdestruct system" was installed at the facility. This system used sodium naphthalide to detoxifytransformer fluids that contained PCBs. The facility operated from 1939 until approximately 1984when operations were transferred to a new facility at Fountain Place Industrial Park, also in MountVernon. The original facility continued to operate the PCB destruct system, and the buildingcontinued to be used as a warehouse.
Casey Fork Creek bounds the east side of the Dowzer property. Since 1976, areas of and nearCasey Fork Creek and the Dowzer facility have been studied for PCB contamination. Soil, streamsediments, surface water, storm water runoff, and fish flesh have all been sampled and analyzed forPCBs among other contaminants. PCBs were detected in storm water runoff samples collected bythe Illinois Environmental Protection Agency (IEPA) in 1976 and 1977 at a storm drain outfallsouth of the Dowzer facility. IEPA conducted a 1977 survey and found elevated PCB levels in fishflesh and stream sediments in Casey Fork Creek. IEPA collected additional data in 1984 and 1985on stream sediments and storm water runoff that implicated the Dowzer facility as an active sourceof PCBs in Casey Fork Creek.
In May 1985, IEPA notified Dowzer of the company's possible violations of the IllinoisEnvironmental 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 todetermine the source of the PCBs. The company completed an initial RemedialInvestigation/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 Suppliesand contained stored drums of oils and cleaning supplies. A third, smaller building next to CastletonAvenue was used for truck maintenance. The PCB destruct facility structure, which consisted of thelaboratory building and several covered aboveground tanks, was in the north-central portion of theproperty (Figure 2). The tanks on the property were in diked containment areas, so tank spills werecontained. Water that collected in those areas during rainfalls was treated by a gravity separator anda charcoal filter system. In addition, the facility had a large concrete loading dock and an adjacentgravel 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 removaland disposal of the warehouse structures and part of the warehouse concrete flooring; excavationand 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, thefloor of the former warehouses, a loading dock, and a small shed. The rest of the area is covered bygravel. 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, thename of Dowzer Electric was changed to Hevi-Duty Electric. (For purposes of this report, the nameDowzer 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 runofffrom the facility to flow toward Casey Fork Creek. The geology beneath the site is described as fillmaterial ranging from 0 to 8 feet thick, with the thickest portion near Casey Fork Creek (6). Belowthe fill are 10 to 15 feet of naturally occurring, clayey silt and clay soils. Beneath those soils is azone of approximately 3 feet of highly weathered siltstone. Massive claystone with areas ofsandstone 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 easttoward Casey Fork Creek (6).
During the initial Remedial Investigation (RI) of the facility in 1986, PCB contamination was notfound in surficial sediments of Casey Fork Creek. When the fire clean-up operations andreplacement of the storm water sewer took place, however, a layer of black material was discoveredbeneath the surficial stream sediments of the creek near the storm water sewer outfall. To furtherdetermine the extent of the PCB contamination, Dowzer initiated a supplemental RI in 1989. Thesupplemental RI included further investigation of the creek, the sanitary sewer that traverses theDowzer 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 ForkCreek next to the Dowzer site were completed in October 1991. To remediate the contamination, asection 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 initialphase of the clean-up had been completed at the time of the visit, the site was still posted with IEPAbanner tape. The tape had been originally placed around the site boundary following the fire. Theonly buildings we saw on the site were the laboratory, the maintenance shop, and a small shed. Theconcrete floor was all that remained of the former warehouses. Access to this portion of the site wasrestricted only by the banner tape. A fenced and locked gate surrounded the graveled parking lot onthe 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, aDowzer 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 associatedwith the Dowzer facility. The final phase of the clean-up included removal of known areas of PCBcontamination along the stream bank and stream sediment in that portion of Casey Fork Creek nextto the Dowzer site, particularly at the outfall of the storm sewer. The creek was to be permanentlyrerouted, which was the best option to address the contamination, around the area of gross PCBcontamination.
At the time of the visit, the creek had already been rerouted, and excavation of the old creek bed wasin progress. After the soil was excavated, it was stockpiled on plastic on the concrete floor of theformer Dowzer warehouse. The stockpiles were then sampled and identified as to PCB content forproper disposal.
Most recently, IDPH staff visited the site on December 1, 1995. All remediation activities at the sitehad been completed, and the site remained abandoned. No further site visits are necessary untildecisions are made as to whether additional work will be done at the site.
The Dowzer site is situated on 4 acres on the southeastern edge of the city of Mount Vernon inJefferson 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 siteis Mount Vernon Township High School, which is approximately 0.5 miles northwest of the site atthe intersection of 7th Street and Casey Avenue. No hospitals or long-term care facilities are nearthe site.
Casey Fork Creek, which flows south along the eastern edge of the facility, is a small stream withhigh flows generally observed in the spring and after rainfall. Portions of the creek near the site areintermittent between rainfalls. Access to the creek near the site is limited. The main channel ofCasey Fork Creek is approximately 27 miles long (6). Casey Fork has a total drainage area of116.2 square miles (6). Land use in the Casey Fork drainage basin includes undeveloped woodlandareas, cultivated farmlands, and urban areas. Seven permitted wastewater dischargers are in theCasey Fork drainage basin (Figure 3). The Mount Vernon Sewage Treatment Plant, one of thepermitted dischargers, is immediately downstream of the Dowzer facility. Four impoundments arein 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 supplementalwater supply reservoirs for the city of Mount Vernon and are upstream of the Dowzer site. TheCasey Fork impoundment is on the northern tip of Rend Lake. It is used by the Illinois Departmentof 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 Riverdrains 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 BigMuddy River. In addition to the Big Muddy River and Casey Fork Creek, major tributaries to thelake include Atchison Creek, Gun Creek, and Rayse Creek (10). The surface area of Rend Lake is18,900 acres with a total drainage area of 488 square miles (10). The northernmost portion of thelake 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 thiswatershed 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 thearea.
Rend Lake was created to provide flood control and community water supplies. It serves as a sourceof drinking water for about 55 communities. Water treatment facilities managed by the Rend LakeIntercity 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 wildlifemanagement.
We can use state health databases to evaluate whether certain health effects are higher than expectedin a particular area, such as an exposed population near a hazardous waste site (1). This section listsavailable databases; a discussion of whether the information can be used to evaluate conditions atthis 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 toexposures to hazardous substances in the work place and in the environment. Specifically, theIHHSR is a unified statewide project that allows collection, compilation, and correlation ofinformation on public health and hazardous substances. The registry contains information about thefollowing categories:
- Cancer incidence.
- Adverse pregnancy outcomes.
- Occupational diseases.
- Hazardous nuclear materials.
- Hazardous substances incidents.
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 arereported to ISCR. In addition, some federal hospitals in Illinois report cases voluntarily. Somebordering states also exchange cancer data with Illinois (16). The ISCR is the prime source forinformation 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 inCasey Fork Creek. Most of the concerns followed local newspaper coverage about PCBs. Earlyreports about PCB-contaminated fish in Casey Fork Creek roused significant attention from thecommunity. Individuals also expressed concern about children playing in Casey Fork Creek and inneighborhoods near the Dowzer site and about the effect of PCBs on the water quality of Rend Lakeand drinking water supplied by Rend Lake.
Fears regarding PCBs at the Dowzer site were again expressed following the fire at the Dowzerwarehouse in June 1988. IEPA conducted residential soil and wipe sampling at that time in anattempt to address some of the questions from people living next to Dowzer property. IEPAcollected a surface wipe sample from a soot-damaged automobile at a residence north of the Dowzersite 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.
The tables in this section list contaminants selected and discussed based upon the following factors (1):
- Concentrations of contaminants on and off the site.
- Field data quality, laboratory data quality, and sample design.
- Comparison of contaminant concentrations and background concentrations withenvironmental media comparison values that are based on carcinogenic and noncarcinogenichealth endpoints.
- Community health concerns.
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 alevel greater than a comparison value for that medium. The list indicates which contaminants areevaluated further to determine if people are actually exposed to the contaminant and if so, whetherthat 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, includeEnvironmental Media Evaluation Guides (EMEGs), Reference Dose Media Evaluation Guide,Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. EMEGs, RMEGs, andCREGs are estimated contaminant concentrations derived from health screening values developedeither 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 healtheffect 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 deemsprotective of public health (considering the availability and economics of water treatmenttechnology) 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 andMCLGs are not.
Before the initial clean-up following the fire in 1989, on-site contamination included PCBs andVOCs. The primary VOCs found were 1,1,1-trichloroethane, chlorobenzene, xylene, carbontetrachloride, 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 beconcentrated 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 andPCB-contaminated soil. A storm sewer was also removed and replaced. Additionally, MW-5 andthe contaminated soil surrounding it were removed. MW-9 was left in place; however, thecontaminated soil surrounding it was excavated.
IEPA collected surface soil samples (3-4 inches deep) in 1984 that contained PCB concentrationsranging from 0.01 to 132 ppm (5). Most of the surface soil samples were collected on Dowzerproperty at the graveled lot next to Casey Fork. Subsurface soil contained PCBs at levels thatranged from less than detectable to 510 ppm, with the highest levels found in samples collected froma depth of 0 to 2 feet near MW-5 (5). PCBs were detected in 15 of the 62 samples collected in1986.
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-trichloroethanein 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.
|Contaminant||Concentration Range (ppm)||Date||Comparison Value (ppm)/Source|
|PCBs (0-4 inches)|
|PCBs (0-24 inches)|
CREG = Cancer Risk Evaluation Guide
ND = Not Detected
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 thearea that contained VOC contamination.
Groundwater was not thoroughly investigated and characterized during the original RemedialInvestigation (RI); therefore, the extent of groundwater contamination was not known when the sitewas 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.
|CONTAMINANT||Concentration (ppb)||Comparison Value (ppb)/Source|
NA/Cancer Group C*
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 fieldactivities were conducted at the Dowzer facility in June 1989. Additional monitoring wells wereinstalled on-site to expand the existing monitoring well network. Groundwater samples collectedduring the supplemental RI did not contain PCBs, and total VOCs were present at levels less thandetectable to 2.81 ppm (6).
Wipe samples were collected from visibly stained wall surfaces in the warehouse. The samples withthe 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. Thestructure itself was composed of a concrete foundation, over which an approximately 6-inch-thickslab floor had been constructed. Construction-grade cinder blocks formed the walls of the structure. The samples were collected before fire destroyed the warehouse.
A storm sewer, which received storm water discharge from upgradient sources, ran along the gravelroadway, immediately south of the Dowzer facility. Water generally flowed through the stormsewer only when precipitation generated water. The storm drain received discharge and runoff fromsurrounding areas and discharged the storm water directly into Casey Fork Creek. To determine thesource 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. Asample of a non-aqueous fluid (oil) was collected from the south outfall. The oil sample containedPCBs at 14,000 ppm. Levels of PCBs in the sediment samples ranged from less than detectable to7.8 ppm, while PCB concentrations in the water discharge samples ranged from less than detectableto 37.0 ppm.
The storm water discharge contained 6.5 ppm total VOCs. The storm water was tested for thepresence 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.
A Mount Vernon sanitary sewer runs in a north-south direction beneath the Dowzer facility. Thesewer then passes under the adjacent M & R property and runs approximately 1/2 miledowngradient to the Mount Vernon Sewage Treatment Plant. Initial measurements of PCBs in thesanitary sewer line near the Dowzer facility were performed in 1985. PCB concentrations rangedfrom below the level of detection to 0.0056 ppm in water samples. The contamination appeared tobe 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 thelaboratory detection limit of 1.0 ppm.
VOC analysis of sanitary sewer water samples (1986) showed the presence of total VOCconcentrations ranging from 0.012-0.355 ppm. Chloroform, tetrachloroethene, and acetone were theonly VOCs detected. Acetone (a common laboratory contaminant) was the VOC present at thehighest 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 petroleumhydrocarbons (TRPHs). PCB levels ranged from less than detectable to 182 ppm with the highestlevel 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 wasdetected in the sample collected near the former eastern warehouse. A source of VOCs wasdiscovered beneath the former warehouse during the clean-up. TRPHs were detected at a range ofless than detectable to 1,930 ppm. The sample containing the highest level of TRPHs was also thesample 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 thatborders 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 thatproperty. During the clean-up activities, a "black layer" was identified within a few feet of theground surface along the southern face of the storm sewer trench between the M & R property andthe Dowzer site. The nature and extent of the contamination was not determined during the clean-upactivities.
PCB concentrations in the soil ranged from less than detectable to 0.573 ppm. VOC concentrationsranged from less than detectable to 0.108 ppm, and TRPH concentrations ranged from less thandetectable to 5,280 ppm. PCB concentrations in the test pits ranged from less than detectable to33.7 ppm. The PCB contamination appeared to be limited to the "black layer" along the stormsewer. The TRPHs detected in the surface soil were attributed to M & R employee parking areasand 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 PCBcontamination as early as 1977. Initial investigations of the creek indicated PCB contamination wasnot present in the surficial sediments downstream of the Dowzer site. During the fire clean-upoperations, however, gross PCB contamination of the creek was discovered. That discovery initiatedthe Supplemental RI.
Sediment samples were collected from the gravel bar next to the Dowzer facility and the creekchannel in 1989. Samples were collected from 1 and 3 foot depths at nine locations within thegravel bar (Figure 6). Fine sediment in the creek channel was collected both downstream andupstream of the facility at 17 locations (Figure 7). The gravel bar samples contained PCBs atconcentrations ranging from 0.01 to 3,250 ppm. Four samples had concentrations greater than 100ppm. The greatest concentrations were detected in samples collected just beyond the end of thestorm sewer discharge pipe. The PCB concentrations generally decreased in samples collecteddownstream of the outfall. These data indicated the storm sewer outfall may have been the conduitby which PCBs entered Casey Fork Creek. Fine sediment samples contained PCB levels rangingfrom 0.007 to 5.22 ppm. The purpose of sampling the fine sediment was to determine if PCBcontamination was below the surficial stream deposits (below 6 inches). In general, the finesediment samples collected upstream of Dowzer did not contain detectable levels of PCBs. Samplescollected near the site and within 1/2 mile downstream contained PCBs ranging from 1.42 to 5.22ppm. Samples collected 3/4 of a mile and further downstream did not contain detectable levels ofPCBs.
IEPA representatives collected sediment samples from Casey Fork Creek for PCB analysis inOctober 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 0.09to 0.35 ppm.
Stream sediment samples were collected in 1986 for analysis of VOCs. Two sediment samples werecollected: 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 thedownstream sample. Additional sampling for VOCs in the sediment was not conducted during theSupplemental RI.
b. Aquatic Biota
Before the Supplemental RI, fish were collected in Casey Fork Creek and the Casey Fork Creekimpoundment 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 hada PCB concentration greater than 6 ppm, several carp and bigmouth buffalo contained PCBconcentrations greater than 2 ppm, and most samples contained PCB concentrations greater than 1ppm. The 1977 data, however, were from whole fish samples rather than edible portions only. Thesamples 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.
|Year||Concentration Range (ppm)|
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 analyzedfor 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 highestconcentration (17.5 ppm) was found in a bullhead sample collected at the station near the gravel barwhere elevated levels of contamination were also detected in the sediment. A sunfish sample alsocollected 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 atthree locations in the creek. A composite sample was collected from each of the pooled locationsand analyzed for PCBs. PCBs were detected in all three samples at concentrations ranging from1.47 to 3.46 ppm.
Fish samples were analyzed for VOC contamination in 1986. The only VOCs detected weremethylene chloride at 3.0 ppm and pentane at 25 ppm, both in the same sample from the samplingstation nearest the Dowzer facility. Although the source of the pentane was unknown, theoccurrence of methylene chloride was attributed to laboratory contamination. No additional VOC analysis of fish samples was conducted during the Supplemental RI.
|SPECIES||PCB Concentration Range (ppm)||# of Samples|
|Large Mouth Bass|
Source: Hunter/ESE, 1989.
c. Surface Water
Surface water samples from Casey Fork Creek have been collected in the past for both PCB andVOC analysis. The most recent sampling was conducted in 1986. No PCBs or VOCs were detectedin any of the surface water samples.
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 extensivestudy effort that included surveys of the stream sediments and aquatic ecology. The water qualityeffort focused principally on traditional water quality parameters and a few heavy metals. Therewere no measurements for organic contaminants. The results of this study indicated that the waterquality of Casey Fork Creek upstream of Mount Vernon was generally acceptable, whereas thewater quality downstream of Mount Vernon was often poor with low concentrations of dissolvedoxygen 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 andland use within the drainage basin. The water quality change reflected the change in land use fromrural and lesser populated areas north of Mount Vernon to the more densely populated andindustrialized area of the city itself (10). The ISWS concluded that the general poor water quality ofCasey 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 thewater quality of the lake itself. The water quality of Rend Lake was reported as generally good withonly occasional occurrences of low dissolved oxygen at deeper levels within the lake (10).
In the past, several off-site soil samples have been collected from various properties next to theDowzer site in an attempt to determine if there had been off-site contamination with PCBs (Figure8). IEPA collected two soil samples in 1981 at locations identified 200 feet northeast and 200 feetnorth of the Dowzer site. Results of that sampling effort identified PCB levels present at 7.7 and 2.3ppm. The depth of the samples was not provided. IEPA collected additional residential soilsamples in October 1985. PCB levels in those samples ranged from below the detection limit to 6.0ppm. Only 2 of the 16 samples contained levels above the detection limit of 5.0 ppm (5.0 and 6.0ppm) 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 ForkCreek. At each location, a surface sample to a depth of 1 inch and composite sample from a depth of1 to 12 inches were collected. Only one sample (collected at the 1-12 inches depth) contained PCBsat levels above the detection limit of 1.0 ppm. A PCB concentration of 15.0 ppm was detected inthis 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 werecarried off-site because of the fire and smoke. IEPA collected a surface wipe sample from asoot-damaged automobile at a residence north of the Dowzer site and a soil sample from a gardenarea at the same residence. The samples were analyzed for PCBs, dioxins, and furans, none ofwhich were above the detection levels. No further residential off-site sampling was conducted during the Supplemental RI.
In preparing this public health assessment, IDPH relied on the information provided in thereferenced documents. IDPH assumed that adequate quality assurance and quality control measureswere followed with regard to chain-of-custody, laboratory procedures, and data reporting. Thevalidity of the analyses and conclusions drawn for this public health assessment are determined bythe availability and reliability of the referenced information.
Discussion in the Supplemental RI report indicated the data contained therein had undergone qualityassurance review. IDPH noted in the report that acetone was detected in nearly every soil andgroundwater sample analyzed for VOCs, including the field blanks. Isopropanol was thedecontamination solvent used during field activity, and evaluation of the analysis results showed adirect correlation between the concentration of acetone and the presence of isopropanol. IDPHbelieves that the presence of acetone in both the soil and groundwater samples is an artifact of theuse 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 maintenancegarage. The buildings were previously used in a limited capacity for repairing trucks and laboratoryanalysis. When not in use, the buildings remain locked at all times. Additional structures on the siteinclude 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 issurrounded by a locked chain-link fence. Although current activities at the site are limited, the sitehas 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, theenvironmental and human components that lead to human exposure are evaluated. An exposurepathway consists of five elements: a source of contamination; transport of the contamination throughan environmental medium; a point of exposure; a route of human exposure; and an exposedpopulation (16).
IDPH categorizes an exposure pathway as a completed or potential exposure pathway if theexposure pathway cannot be eliminated. In a completed exposure pathway, the five elements arepresent. The exposure to the contaminant has occurred in the past, is occurring, or will occur in thefuture. Potential pathways, however, include pathways that have at least one of the five elementsmissing, but data are not available to verify the element exists. Potential pathways indicate exposureto 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 neverbe present (16).
Currently, no completed pathways have been associated with the site. The potential humanexposure pathways to site contaminants include ingestion, inhalation, or dermal absorption ofcontaminants in groundwater, surface water, and soil or dust. Additional potential pathways include ingestion of contaminated food stuffs (primarily fish), inhalation of fugitive volatile airemissions and dermal absorption of stream sediments.
As previously discussed, groundwater use in the area is minimal. The surficial aquifer, whichexhibited contamination with site constituents, does not have sufficient thickness to provide anadequate water supply, and no site constituents appeared to have migrated from the shallowgroundwater 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 obtainswater from Rend Lake. Therefore, exposure to contaminants in groundwater through ingestion ofdrinking water, dermal contact and absorption, and inhalation of aerosolized or volatilizedcontaminants 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 theDowzer site, Casey Fork Creek empties into Rend Lake which serves as a public water supply for55 communities. Surface water samples of Casey Fork Creek did not contain detectable levels ofany of the contaminants associated with the site. In water, adsorption to sediments or other organicmatter is a major fate process for PCBs rather than remaining in the water column. VOCs aregenerally 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 usingRend 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 theDowzer site. Exposure through direct dermal contact with contaminated sediments in the creek fromactivities such as wading or swimming could have occurred, but no one is expected come in contactwith 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 aquaticorganisms inhabiting the stream. Ingestion of the aquatic biota (fish, crayfish) caught out of theimpacted waterways or of other animals that may feed or drink from these waters may result inexposure. We do not know if anyone is fishing in areas where the fish and invertebrates were shownto contain PCBs.
Inhalation, ingestion, and dermal contact from fugitive dusts transported off-site to the surroundingpopulation are also potential routes of exposure. Normal activities and traffic on-site, however, areminimal. 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 AnalysesSections, the primary contaminant of concern is PCBs. The most likely exposure scenario to occurwould involve individuals using Casey Fork Creek for fishing. These individuals may be exposed toPCBs through ingestion of contaminated fish or other aquatic biota such as crayfish. Some dermalabsorption of contaminated sediments may occur if people also wade in the creek. PCBs have beenthe subject of a Toxicological Profile developed by the Agency for Toxic Substances and DiseaseRegistry (ATSDR).
PCBs are very persistent environmental contaminants comprised of a family of man-made chemicalsthat contain 209 individual compounds (2). The environmental persistence of PCBs generallyincreases 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 familyidentified 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 aquaticenvironment and resulting bioconcentration. PCBs have poor solubility in water but good solubilityin organic materials such as fats, and therefore, tend to accumulate in fat-rich tissue in animals. Toreduce the risk of exposure from eating fish, the fat-soluble PCB contamination can be reduced byremoving 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 dripaway from the finished meal.
In humans, PCBs tend to accumulate in adipose tissue, blood, and breast milk. Heavily chlorinatedrepresentatives 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 tohigh PCB concentrations in the breast milk of lactating mothers if the mothers consume largeamounts of contaminated fish. Because PCBs can concentrate in milk, pregnant women or womenwho may become pregnant are also a population of concern. A number of studies indicate thatPCBs can cross the placenta and locate in the fetus. Embryos, fetuses, and infants are potentiallysusceptible because they generally lack the enzyme systems that facilitate detoxification andexcretion of PCBs (2).
Birth weight, head circumference, and gestational age were observed to be slightly decreased innewborns of mothers who were consumers of fish (2). Other studies found that consumption ofPCB-contaminated fish by mothers and serum cord levels of PCBs were predictors of impaireddevelopment and abnormal reflexes in infants. These studies were not conclusive, however, becauseno 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 PCBexposures that are much higher than those received by the general public. In the United States, acuteadverse health effects such as those previously described have not been observed in people withnonoccupational exposure. In Japan, serious health effects were observed in individuals whoconsumed 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 mixturesproduced in the United States in that they have different chlorine content and a greater percentage oftoxic 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 regardingthe carcinogenicity of PCBs in humans is inadequate, PCBs are considered probable humancarcinogens based on the animal data (2).
There was no site specific health outcome data identified or generated that was appropriate for thissite. The study population associated with this site is too small for a relevant cancer incidenceevaluation. Cancer incidence information for Jefferson County as a whole would not truly reflect any occurrence related only to the site.
As stated previously, concerns had been voiced regarding the PCB contamination at the Dowzer siteand in Casey Fork Creek. In response to concerns of PCB contamination following the fire at theDowzer site, IEPA collected surface wipe samples and soil samples at surrounding residentialproperties. The samples were analyzed for PCBs, dioxins, and furans, none of which were presentabove 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 apparentpublic health hazard at this time. Much of the concern about the site has been eliminated with theclean-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 thesite, any exposure to the contamination would most likely be limited. Portions of Casey Fork Creeknext to and downstream from the Dowzer site typically have low flow rates, except in spring andafter rainfall, and become intermittent during periods of low rainfall. Creek access is limited inthese areas. Those factors would generally make this portion of the creek unattractive forrecreational use such as wading, swimming, and fishing. No other potential exposure pathwayswere identified that would likely result in exposure to site-related contaminants.
The surrounding community voiced concerns in the past regarding the PCB contamination at theDowzer site, particularly the reports of PCB contamination of fish in Casey Fork Creek. Theconcerns were alleviated following the removal action at the site and the clean-up of Casey Fork Creek.
- Periodically inspect the site area to ensure that the site remains secured until remediation has been completed according to IEPA regulations and no further action is required at the site.
- When no further action is necessary at the site, properly abandon and seal in accordance withthe Illinois Water Well Construction Code, Section 920.120, any remaining on-sitemonitoring wells that will no longer be used for groundwater monitoring. The Code statesthat the owner of a water well shall assure that such well is sealed within thirty (30) days after it is abandoned and no longer used for the purpose for which it was intended.
- Conduct additional fish sampling at the stations in Casey Fork Creek. The most recent fishsampling activity associated with the site was conducted in 1989. At that time, PCBconcentrations in the fish ranged from 0.32 to 17.5 ppm. Sediment samples collected in1995 in Casey Fork Creek revealed a decrease in PCB concentrations, which ranged from0.09 to 0.35 ppm.
- If data become available suggesting that human exposure to hazardous substances at levelsof public health concern is occurring, the need for any follow-up at the site will bereevaluated. New environmental, toxicological, or health outcome data may determine theneed for additional actions at the Dowzer site.
Preparer of Report:
Lynn M. Stone
Illinois Department of Public Health
Reviewers of Report:
Bruce C. Barrow
Illinois Department Of Public Health
Technical Project Officers
- ATSDR Health Assessment Manual. Agency for Toxic Substances and Disease Registry,Atlanta, GA. 1989.
- ATSDR Draft Toxicological Profile for Selected PCBs. Agency for Toxic Substances andDisease Registry, Atlanta, GA. 1987.
- Central States Environmental Services, Inc. (CSES). Dowzer Electric Site, Mount Vernon, IL, Phase II Cleanup Report. 1989.
- Central States Environmental Services, Inc. (CSES). Dowzer Electric Site Phase IV Work Plan. 1990.
- Environmental Research and Technology. Report on Remedial Investigation/FeasibilityStudy of Dowzer Electric, Mount Vernon, IL. 1986.
- Hunter/ESE. Final Report Supplemental Remedial Investigation Dowzer Electric StudyArea, Mount Vernon, IL. 1989.
- Illinois Environmental Protection Agency. An Intensive Stream Quality Investigation of the Casey Fork Basin - Summer 1977. 1979.
- Illinois Environmental Protection Agency. DWPC/Monitoring Unit. Surficial SedimentSurvey of Casey Fork in the Vicinity of Dowzer Electric Company, Mount Vernon, IL.1985.
- Illinois Environmental Protection Agency. DLPC/DWPC, File Information, Springfield and Marion, IL. Dowzer Electric Site, Mount Vernon, IL. 1990.
- Illinois State Water Survey. Quality Assessment of Rend Lake and its Tributaries. Prepared for Greater Egypt Regional Planning and Development Commission. 1978.
- Illinois State Water Survey. Groundwater Section, Champaign, IL. Geological and Water Survey Well Records for Township 2S and 3S, Range 3E for Jefferson County, Illinois. 1990.
- Leifer A., Brink R.H., Thom G.C., Partymiller K.G. Environmental Transport andTransformation of Polychlorinated Biphenyls. EPA-56015-83-025. Washington, DC: Officeof Pest. Tox. Sub., NTIS No. PB84-142579. 1983.
- Sittig, Marshall. Handbook of Toxic and Hazardous Chemicals and Carcinogens. Noyes Publications, Park Ridge, New Jersey. 1985.
- United States Census Bureau. Statistic Data for Mount Vernon, IL. Preliminary 1990.
- United States Environmental Protection Agency. Research and Development, Health Effects for Polychlorinated Biphenyl. Environmental Criteria and Assessment Office, Cincinnati, OH. 1984.
- Agency for Toxic Substances and Disease Registry. Public Health Assessment GuidanceManual. Atlanta, GA. March 1992.