PUBLIC HEALTH ASSESSMENT
KOHLER COMPANY LANDFILL
KOHLER, SHEBOYGAN COUNTY, WISCONSIN
In the following discussion, "on-site" refers to the area bounded by the Sheboygan River, County Highway A and County Highway PP (Appendix A, Maps 1 and 2), and "off-site" refers to all other areas including the river. Technically, however, the Kohler Company Landfill National Priorities List site does not include the Kohler Company property on the floodplain between the waste fill area and the river. This section of the assessment describes how "chemicals of concern" are distributed in soil, water, biota, and air around the site. "Chemicals of concern" are those that occur above a level where the maximum plausible exposure to the contaminated material might affect human health. This assessment addresses only those contaminants that the authors judge to be present at levels of concern. Typically, health assessors use ATSDR's Minimal Risk Levels, EPA's Reference Doses, or EPA's Cancer Slope Factors to decide whether chemicals are present at a level of concern at a site. For carcinogenic chemicals a level of concern refers to a concentration where a lifetime of exposure to the most contaminated material might result in an upper-level estimated risk of one cancer for every one million people exposed. Levels of concern are listed as "comparison values" in Table 2 below. This assessment evaluates chemicals of concern to determine whether they do pose a significant threat to public health. Chemicals of concern listed below do not necessarily pose a public health hazard. As explained later in this assessment, the extent of health hazard depends on the pathways by which people are exposed, the extent of human exposure, and the toxic properties of the chemicals.
Limited groundwater, waste and leachate analysis was performed prior to 1984, when the sitewas added to the National Priorities List (NPL). In 1976 a contractor for Kohler installed tenmonitoring wells on the site in the shallow aquifer. These wells are being analyzed quarterly forchemical oxygen demand, phenols and conductivity. Once a year, these wells were analyzed forsome metals. Nine additional monitoring wells were installed in 1986, and analyzed forinorganic chemicals along with the original ten wells.
Waste taken from plant processes was analyzed for metals in 1982 by a contractor for Kohler(10). WDNR analyzed surface runoff from the site for metals and indicators in 1979 (1). Leachate was analyzed for lead and cadmium in 1981. Surface soil samples were not analyzedprior to listing on the NPL.
After the site was added to the NPL in 1984, Remedial Investigation activities began. Phase I ofthe RI, was performed by Weston Inc. and completed in 1988. During this phase, runoff, waste,leachate, and surface soils were analyzed (11). Radian Corporation performed Phase II, which was completed in 1989. Runoff, leachate, and surface soils were analyzed in addition to the installation of three more bedrock monitoring wells for the beginning of hydrologeologic investigations (12). Phase III was performed by Geraghty and Miller and completed in 1991. In this phase, more monitoring wells were installed, waste was characterized, and the geology of the area was investigated more fully. During 1992, some monitoring wells were analyzed for PCBsand some volatile organic compounds (VOCs).
During Phase I of the the RI, five on-site surface soil samples were analyzed for some semivolatile organic compounds (SVOCs), PCBs, and metals. Samples were collected from the top four to six inches of the soil (2, p.61). Four of the samples were taken from outside the waste disposal area and near the Sheboygan River and another was taken from the waste disposal area (Appendix A, Map 2). The sample taken from the waste disposal area was also analyzed for VOCs. Surface soil samples were taken from an area at the bottom of the slope forming the waste disposal area boundary and receives leachate and runoff water from the landfill (2, p.106). As explained in the health assessment for the Sheboygan River and Harbor, there also are significant upstream sources of contamination to the floodplain here. Samples from nine different locations were also analyzed during Phase II of the RI. PCBs were detected at concentrations ranging from 2.2 to 4.3 mg/kg in surface soil samples from locations between the landfill and the Sheboygan River. No other compounds were detected in these samples at a levelof health concern.
Waste from plant processes was analyzed in 1982 but waste borings taken from the landfill were not analyzed until Phase III of the RI. Since the waste borings represent present landfill conditions more accurately than waste analyses, only the RI waste borings will be discussed in this assessment. Liquid and sludge waste was deposited in four areas in the Kohler Landfillwhile other areas were used for foundry sand and related wastes (see map in Appendix A). During the RI, 15 waste borings were completed across the landfill. Waste from two depths was analyzed for some borings, such that 24 total samples were analyzed. Six of these borings were in areas of liquid and sludge waste disposal while the remainder were in areas of foundry sand disposal. VOCs detected at a level of health concern were trichloroethylene (51 mg/kg) and 1,2-dichloroethylene (38 mg/kg) in an 8-foot deep sample taken from Boring 13. This area was not used for liquid waste disposal. Various polyaromatic hydrocarbons (PAH) including benzo(a)pyrene were found at 2-4 mg/kg in a 36-foot deep sample taken from Boring 10 adjacent to a suspected waste burial area. Lower PAH concentrations were found in 22 of the 24 samples. PCBs were found in Borings 4,5 and 6 at concentrations of 2 to 540 mg/kg.
Surface water runoff
In the 1979 surface water runoff sample, copper and zinc were detected at levels exceedingWDNR ecological criteria but not at a level of human health concern. During the RI, surfacewater runoff was sampled from three locations east of the landfill and one location to the south(Appendix A, Map 2). No VOCs, SVOCs or metals were detected in these samples which were at a level of health concern. PCBs have not been analyzed in surface water runoff samples.
Three leachate samples were taken from east of the landfill during the RI. No compounds weredetected in leachate at concentrations of health concern. PCBs have not been analyzed inleachate samples.
Groundwater from ten monitoring wells in the shallow aquifer has been analyzed quarterly forchemical oxygen demand, phenol and conductivity by a contractor for Kohler since 1976. In1986, nine additional wells were added. Once a year, these wells were tested for some metals. Cadmium, chromium and lead were not among the metals analyzed. Therefore, pre-RIgroundwater sampling cannot be evaluated from a health perspective.
A total of thirty-eight on-site wells and ten "background" (in the opposite direction of calculatedgroundwater flow) were analyzed during the remedial investigation for VOCs, SVOCs, metalsand indicators (see Appendix B for a list of chemicals tested and Appendix A, Map 4 for welllocations). The Kohler Company analyzed groundwater samples for PCBs after completion ofthe RI. A summary of well depths is provided in Table 1.
Chemicals of concern identified in on-site wells are summarized in Table 2. Only the resultsfrom Phase III will be used in addition to the results of the 1992 sampling. In general, the highestcontaminant levels were found in wells 11 and 11D in the surficial and lower till in the southernportion of the landfill. This well is just east of the Old Waste Pit. The most contaminated wellsin the shallow bedrock are located at the bottom of the landfill slope along the Sheboygan River.
Groundwater from monitoring wells clusters 2 and 11 was also analyzed for PCBs in December1991, January, September, and December 1992 (13, 14). One PCB mixture, Arochlor 1242, was found in unfiltered samples from the shallow aquifer in wells 11 and 11D, and Arochlor 1232 was found in well OW-2. No PCBs were detected in filtered samples of groundwater. All three wells were constructed with well screens very close to the waste mass.
The RI states that "elevated VOC levels" were detected in air in or adjacent to boreholes duringdrilling operations (2, p.127). However, the specific VOCs were not identified.
The types of VOCs detected are likely similar to those found in the EPA's analysis of landfill soilgases in June 1990 (2, App. S). Probes were installed at several depths in grids (Appendix A,Map 3) across the waste fill area. All the VOCs listed in Table 2 were also detected in soil gases, except 1,2-dichloroethane. Benzene was found at levels up to 750 µg/m3, and other VOCsexceeded 1,000 µg/m3. No testing of ambient air above the landfill was performed.
|Chemical||Surficial Till||Lower Till||Shallow Bedrock||Lower Bedrock||Standard1||Comparison Value|
|cis: 702 trans: 1002|
|Arochlor 1242 (PCBs)||1.7||ND||ND||ND||-||0.0053|
NB: Not above background levels.
1 Wisconsin Groundwater Enforcement Standard.
2 U.S. Enviromental Protection Agency Maximum Contaminant Level.
3 10-6 risk based upon EPA Cancer Potency Factor.
4 ATSDR Environmental Media Evaluation Guideline for child's drinking water.
5 Based on EPA Oral Reference Dose.
6 EPA Action Level
Source: 2, Figures 79-82; 14.
Water samples were collected from the Sheboygan River immediately downstream of the KohlerLandfill in 1987-1988 as part of the Sheboygan River and Harbor Remedial Investigation. Samples were collected under conditions of high, medium, and low flow. The sampling wasused for a mass balance of PCBs and metals in the Sheboygan River system and was not intendedto evaluate the effects of the Kohler Company Landfill on the river. None of these samplescontained contaminants at a level of health concern. Only during low flow conditions were therelevels of particulate lead and cadmium (26 µg/L and 1 µg/L, respectively) downstream of thelandfill that exceeded concentrations found upstream (15).
Sediments in the Sheboygan River were tested as part of the Sheboygan River and HarborRemedial Investigation. As was the case with the water column samples, these sediment sampleswere not taken for the purpose of evaluating the effects of the Kohler Company landfill on theriver. A number of contaminants were found in sediment taken from areas adjacent to the Kohlersite including PCBs. A known source of PCB contamination in river sediment lies upstream ofthe Kohler Company Landfill. For a discussion of Sheboygan River sediments, see the PublicHealth Assessment for the Sheboygan River and Harbor (16).
During the Remedial Investigation, five monitoring wells located on the other side of theSheboygan River were analyzed for the VOCs, SVOCs, and metals as the on-site wells (seeAppendix B for the chemicals tested). Three of these wells are drilled into the lower till, two intoshallow bedrock (upper 20 feet of dolomite) and two into deep bedrock (penetratingapproximately 50 feet into the dolomite). No contaminants were detected in these wells at a levelof health concern.
Off-site monitoring wells were also analyzed in December 1991 and January 1992 for the sameVOCs, SVOCs and metals as in the RI (Appendix B) and polychlorinated biphenyls (13). Benzene (15 µg/L; Wisconsin Groundwater Enforcement Standard, 5 µg/L) was found in all samples from well 15 southwest of the site and across the Sheboygan River. Because this well is near a highway, it is possible that the highway is a source of the benzene, a constituent of gasoline.
Also during the RI, seven non-potable water wells and one residential well located within one-half mile of the site were analyzed for VOCs, SVOCs, and metals (Appendix B). Detection limits for many of these chemicals were not low enough to determine possible health impacts. Only methylene chloride was detected in these samples at a concentration above the detection limit but the same compound was found in sample blanks. No other contaminants of concernwere found. The residential well was sampled and analyzed for VOCs again in 1991 and 1992 using lower detection limits. No VOCs were detected (17, 18).
Toxic Chemical Release Inventory
A search of the 1989 Toxic Chemical Release Inventory for the ZIP code which includes the Kohler Landfill site (Kohler, WI, 53044) revealed that direct discharges by the Kohler Company factory to the environment may be another source of chemical exposure in the vicinity. Air and water emissions of the chemicals of concern identified at the site are listed in Table 3. The Toxic Chemical Release Inventory is used here to provide information on additional, nearby sources of chemicals of concern at a site. Because there are nearby emissions of many of the same chemicals found at the landfill, it would be difficult to evaluate the extent to which VOCs in landfill soil gases are emitted to the air.
|Chemical||Air Discharge (lbs/yr)||Water Discharge (lbs/yr)|
Source: Toxic Release Inventory, 1989
During Phase I of the RI, a number of VOCs were detected in both samples and blanks. For Phases II and III, all sample collection, storage and analysis was performed using EPA-certified procedures. The WDOH relies upon the QA/QC procedures outlined in the report.
During the site visit, the WDOH representatives noted steeply sloped pits into which foundrysand and other refuse was being deposited. This substance had the consistency of fine sand.Individuals trespassing on the property could have become trapped in the pits. According toWDNR, slurried wastes are now deposited in shallow trenches such that this hazard has beenreduced. The site is also posted and patrolled regularly, and there were no indications of peopletresspassing near the pits.
This section of the assessment describes how people may become exposed to contaminantsassociated with the site. The "Completed Exposure Pathways" section discusses the food chainpathway of exposure, where there are clear indications that people were exposed to contaminantsin fish from the Sheboygan River and for which there is sufficient information to evaluate thatexposure. The "Future Potential Exposure Pathways" section refers to exposure that may occurin the future if the groundwater were not cleaned up sufficiently. "Potential pathways" refers toexposures where there is insufficient information to link the chemical to a known level ofexposure among an identified population. For each pathway, we describe the chemicals ofconcern, how the chemicals move to where people may be exposed to them, and the people whomay be exposed.
It is unclear from the RI report whether PCBs present in waste have migrated to leachate orsurface water runoff and entered Sheboygan River sediment. The RI showed no indication thatPCBs currently are flowing from landfill wastes to the river. In addition, significant upstreamsources of PCBs in the Sheboygan River also exist. For a discussion of these other sources, seethe Public Health Assessment for the Sheboygan River and Harbor. Nevertheless, due to thepresence of PCBs in waste and unfiltered groundwater near the waste, there may be a potentialfor the compounds to migrate in leachate. Even though the available information does notestablish a pathway from the waste to the river, PCBs are discussed here because PCBs arepresent at the site and because they occur at levels of concern in river sediments and biota nearthe site.
PCBs present in Sheboygan River sediments are known to bioconcentrate in aquatic species (19). Some species of fish in the Sheboygan River have been found to contain concentrations of PCBsin exceedance of the Food and Drug Administration (FDA) standard of 2 parts per million. WDOH and WDNR have issued a health advisory not to consume species of fish with PCBconcentrations over FDA standards from the Sheboygan River (20). For a list of these species, see Table 4.
Many individuals, including members of the non-English speaking community, remain unaware of the health advisory and continue to consume contaminated fish (21). As a result, WDOH has sponsored a number of workshops in the area to teach local residents which types of fish are not healthy to consume.
PCBs have also been found in tissues of mallard ducks caught in Sheboygan County atconcentrations of up to 15.0 ppm wet weight (15, App. A). As a result, WDNR has issued anadvisory discouraging consumption of this species (22). However, many individuals who remain unaware of this advisory may consume mallard ducks from this area.
Table 4: Species of Sheboygan River fish on
WDNR/WDOH Health Advisory
|Group 1||Group 2||Group 3|
|Coho salmon <26"||Rainbow Trout||Bluegill|
|Chinook salmon <21"||Brook Trout||Crappie|
|Coho salmon >26"||Rock Bass|
|Chinook salmon 21-32"||Carp|
|Chinook salmon >35"|
Group 1: Contaminant levels in 10 percent or less of these fish are higher than one or more health standards. Eating these fish poses the lowest health risk. Trim the fat and skin from these fish before cooking and eating them.
Group 2: Contaminant levels in more than 10 percent but less than 50 percent of these fish are higher than one or more health standards. Children under 15 and women of childbearing age should not eat Group 2 fish. You should also limityour overall consumption of other Group 2 fish and trim skin and fat from these fish before cooking and eating them.
Group 3: Contaminant levels in 50 percent or more of these fish are higher than one or more health standards. No one should eat these fish.
Residential Drinking Water
Residential drinking water is not an exposure pathway at present. However, if the site is leftunremediated, contaminants present at the site might migrate to off-site residences andcontaminate nearby wells in the future. Data presented in the RI indicate that both the upper andlower groundwater systems under the landfill contain site-related contaminants. Nocontaminants were detected in one off-site residential and seven nearby non-potable watersupplies. Flow in the till aquifers is toward the Sheboygan River. A groundwater flow modelsuggestes that groundwater derived from local recharge in areas around the landfill flows to theriver. The dolomite aquifer also discharges to the Sheboygan River, but some groundwater inthis aquifer may also flow under the river through cracks in the dolomite and toward LakeMichigan. The regional direction of groundwater flow is east toward Lake Michigan (2,pp.78-85). Therefore, the possibility that contaminants have migrated or will migrate under theSheboygan River to nearby wells cannot be excluded completely. Since the precise directions ofgroundwater flow have not been determined, twenty-two wells located between one-half and onemile of the Kohler site may be susceptible to contamination (see Appendix A for map). The Kohler Company has proposed to continue testing groundwater monitoring wells across the river from the landfill (6). Such testing would provide advance warning if VOCs were to migrate beyond the river.
Present Completed Exposures
The only potentially site-related contaminant humans are currently being exposed to is polychlorinated biphenyls through consumption of PCB-contaminated fish. No estimates of numbers of individuals who are not following the fish consumption advisory or the quantity of fish they consume are available.
An extensive amount of literature has developed regarding the potential toxicity and carcinogenicity of polychlorinated biphenyls. Neurobehavioral deficits were noted in infants whose mothers were exposed to PCBs from contaminated fish before and during pregnancy (23). Lower birth weight has also been reported in infants born to mothers consuming PCB-contaminated fish (24). Fish consumed by mothers in these studies were from the Great Lakes and PCB concentrations were similar to those found in Sheboygan River fish. PCBs are also listed as probable human carcinogens by EPA and those consuming contaminated fish would be at an increased risk for liver cancer development. See the Public Health Assessment for the Sheboygan River and Harbor for a more detailed discussion of the toxicological implications of eating fish from the Sheboygan River.
Potential Future Exposures
Under a "worst case scenario," contaminants at concentrations present in the shallow aquifer at the Kohler Landfill could migrate to an off-site well. Realistically, these contaminants would be diluted before they reach off-site wells, therefore, exposures would most likely be much lower than those from concentrations found in the shallow aquifer. However, for the purposes of this discussion, the assumption is that, over their lifetimes, nearby residents will consume two liters of drinking water daily with the same contaminant concentrations as those in the shallow aquifer.
The EPA has withdrawn its former classification of trichloroethylene as a probable human (class"B2") carcinogen while the agency is reviewing additional data. An individual drinking watercontaminated with trichloroethylene may be at an increased risk of cancer development since oralexposure to the compound caused increases in hepatocellular carcinomas in mice. In addition,consuming water containing 14,000 µg/L, the highest concentration found in the shallow aquifer,would probably also be associated with liver and kidney damage. Inhalation exposure at thisconcentration would also be associated with neurological problems such as headaches, ataxia andneuropathies. Other health effects of chronic oral exposure have not been studied (25).
The carcinogenicity of this compound is not known since the EPA has not classified thecarcinogenicity of 1,1-dichloroethane. No health effects are expected to result from consumptionof this compound at the concentrations found near the Kohler site. Consuming water with thiscompound at the concentration found in the shallow aquifer would be associated with liver andkidney damage (26).
The EPA classifies 1,1-dichloroethylene as an possible (class "C") human carcinogen. The basis for this classification is that kidney tumors were observed in one strain of mice upon inhalation exposure. Based upon this study, estimates of cancer risk associated with specific ingestion and inhalation doses have been published. Use of these estimates indicates a low excess cancer risk for individuals consuming water containing this chemical at 10 µg/L, the highest concentration found under the Kohler Landfill (27).
The EPA classifies 1,2-dichloroethane as a probable (class "B2") human carcinogen. Tumors inlaboratory animals have been noted at multiple sites following oral exposure. Exposure to waterat the highest concentration found under the Kohler site would be associated with an increasedcancer risk. No other health effects would be expected (28).
The EPA has not classified the carcinogenicity of trans-1,2-dichloroethylene. In animals,inhalation exposure has been associated with liver damage and changes in blood enzymes andcytology and this effect may occur in humans drinking the compound for a long time at theconcentration occurring under the Kohler Landfill. In addition, the compound evaporates easilyfrom water such that showering or bathing may provide significant inhalation exposure. Thoseinhaling the compound would have neurological effects such as headaches, ataxia andneuropathies (29).
The EPA has not classified the carcinogenicity of 1,1,1-trichloroethane. Those ingesting andinhaling the compound may have an increased risk of reproductive problems since exposure tothe compound was associated with birth abnormalities in both an animal study and in anepidemiologic study with concentrations similar to those found under the Kohler Landfill (280µg/L). Other health effects of consuming the compound at this concentration have not beenstudied (30).
Health effects associated with benzene exposure include leukemia induction and hematologicalabnormalities. The EPA classifies benzene as a known human (class "A") carcinogen. Inhalation exposure to benzene has been associated with leukemia induction in both humanepidemiology studies and animal studies. Oral exposure has also been found to increase tumorincidence in animals. Other health effects which may be associated with benzene exposure viainhalation include anemia and leukopenia. Consuming water containing the concentration ofbenzene found under the Kohler Landfill, 50 µg/L, over a lifetime would be associated with alow excess cancer risk (31).
The EPA classifies vinyl chloride as a known human carcinogen. An individual consumingwater containing vinyl chloride at the highest concentration found under the Kohler Landfill, 430µg/L, over a lifetime would have a very high increased risk of cancer development. In addition,exposure to the compound has also been associated with reproductive problems and such aneffect would be likely from consuming water containing this concentration. Liver and kidneyproblems would also likely develop (32).
2-Methylphenol, 4-Methylphenol and 2,4-Dimethylphenol
The EPA classifies 2-methylphenol and 4-methylphenol as possible human (class "C")carcinogens. No human data are available. No data are available for 2,4-dimethylphenol. Because the EPA has not issued cancer slope factors for either substance, it is not possible toestimate the cancer risk from human exposure to drinking water containing the concentrationsfound under the Kohler Landfill. Dermal papillomas have been induced in mice when4-methylphenol is painted on the skin of mice. No oral exposure studies of 2- or 4-methylphenolhave been performed. Neither the EPA nor ATSDR has determined safe levels of exposure tothese compounds.
The carcinogenicity of silver in humans has not veen evaluated by the EPA. Long-term ingestionof silver is associated with neurological effects such as lethargy and increased heart size inanimals. These effects may occur in individuals consuming water at the concentration foundunder the Kohler Landfill, 148 µg/L (33).
Consuming water containing cadmium at the concentration found under the Kohler Landfillmight be associated with stomach irritation, leading to vomiting and diarrhea. In addition,kidney damage would likely result. The oral carcinogenicity of cadmium has not been evaluated(34).
Lead ingestion has been found to cause neurological problems including learning disabilities in exposed children. Consuming water containing lead at the concentration found under the Kohler Landfill would be associated with this problem. No other health effects would be expected (35).
Consuming water with concentrations of nitrates found under the Kohler Landfill would beassociated with methemoglobinemia in infants under six months of age. The effects of nitrateingestion have not been studied in adults.
"Health outcome data" is a phrase referring to records of death and disease. When there isevidence that people near a site have been exposed to contaminants at levels that could lead to anincrease in rates of death or disease, a review of health outcome data may be appropriate. Areview also may be appropriate if there are reports of unusual clusters of diseases near a site. Except for consumption of PCBs in Sheboygan River fish, there is no evidence of significantpublic exposure to chemicals found at the landfill, and WDOH is not aware of any reports ofclusters of chronic disease near this site. For an evaluation of health outcome data associatedwith human exposure to contaminants in Sheboygan River fish, see the Public HealthAssessment of the Sheboygan River and Harbor. There is a known, upstream source of PCBs tothe river system, and that assessment discusses the sources, exposures, and health effects ofPCBs in the Sheboygan River.
Some concerns have been expressed about the effects of VOCs in groundwater under the landfilldischarging to the Sheboygan River and the river food chain. This health assessment dealsspecifically with possible effects on human health and does not address effects on the aquatic lifeof the river, other than as people may be affected by contaminants accumulating through the foodchain. Because the chemicals moving in the groundwater are volatile (they "evaporate" fromwater readily) and because the flow of river water is so great compared to that of groundwaterdischarging from the landfill, VOC levels in river water are not sufficient to pose a human healthhazard. The levels are not a threat to people who wade or swim in the river. Neither are theysufficient to affect the safety of eating the fish. The levels of PCBs accumulating in river fish,however, does pose a health threat to people who might eat the fish.