PUBLIC HEALTH ASSESSMENT
OUTBOARD MARINE CORPORATION
WAUKEGAN, LAKE COUNTY, ILLINOIS
Ever since PCBs were found in Waukegan Harbor, sampling has focused primarily on these compounds. With a few exceptions discussed below, the occurrence of other possible contaminants have not been studied.
1. Waukegan Harbor
On April 29, 1980, EPA found 12.49 nanograms per cubic meter of PCBs in the air at a public dock in Waukegan Harbor (Mason and Hanger-Silas Mason Company, Inc., 1981b); however, the report does not identify the exact location from which the sample was taken.
ATSDR has not yet developed health criteria for PCBs in air. Possible effects of the ongoing remediation on airborne PCB concentrations at Waukegan Harbor are discussed in the Pathways Analysis section of this document. Concentrations of any other possible airborne contaminants are unknown. The pleasure boat facilities in the harbor have fuel docks, which would liberate volatile organic compounds (VOCs). PAHs are common combustion products produced by boat engines and other engines and many industrial activities. They are commonly elevated in city environments.
PCBs bioaccumulate and biomagnify in the food chain and can reach high concentrations in fish.
There has been limited sampling of fish within Waukegan Harbor itself. For 1976 to 1981, PCB
levels in several types of fish were reported by Harris (1982):
|(1)||Group A--coho salmon and rainbow trout;|
|(2)||Group B--black and white crappie, largemouth bass, shiners, sunfish, and yellow perch;|
|(4)||Group D--brown and black bullhead, carp, and white suckers;|
|(5)||Group E--bloater chub, lake herring, and whitefish; and|
|(6)||Group F--lake trout.|
It is unknown whether whole fish or filets were used for these analyses. Because PCBs tend to accumulate in fat, a filet can have considerably less contamination than the whole fish has. The PCB levels of the Group A fish (Table 1) were slightly elevated in some samples and generally typical of Lake Michigan background levels (Table 2; Harris, 1982). Evidently, these fish had been exposed to PCB contamination in their food and/or the water column (Harris, 1982).
The Illinois Department of Conservation collected fish from Slip 1 in Waukegan Harbor on September 26, 1980, and had them analyzed for PCBs (Table 3). These were whole fish samples, so the concentrations in the eaten part of the fish could have been considerably lower.
Possible effects of the ongoing remediation of Waukegan Harbor on fish PCB concentrations are discussed in the Pathways Analysis section of this document.
The concentrations of any other possible contaminants in the fish of Waukegan Harbor are unknown. Commercial PCB mixtures are often contaminated with polychlorinated dibenzofurans at levels of several tenths of a part per million. These chemicals bioaccumulate readily (ATSDR, 1991) and might also be elevated in the fish of Waukegan Harbor. Cadmium (not site-related) is elevated in the sediments (discussed in Sediments subsection). Consequently, it may be elevated in the fish of Waukegan Harbor.
Muck makes up the top layer of bottom sediments in Waukegan Harbor. This layer is most heavily contaminated around the former OMC outfall in Slip 3 (Figure 7). The pollution is not uniform, but it occurs in hot spots with up to 420,000 ppm of PCBs. In general, Slip 3 has more than 500 ppm of PCBs, the Upper Harbor (between Slips 1 and 3) has 50 to 500 ppm, and the remainder of the harbor has 10 to 50 ppm. Near the outfall in Slip 3, PCB contamination has penetrated through the sand layer to the top of the silt/silty clay stratum (Figure 8). About 7,300 cubic yards of muck have more than 500 ppm of PCBs (A1 to A6 in Figure 9), 45,000 cubic yards have more than 50 ppm (B1 to B5), and 166,000 cubic yards have more than 10 ppm (C1 to C6). The amounts of PCBs are difficult to estimate because of their skewed distribution; however, Table 4 gives one estimate (Mason & Hanger-Silas Mason Company, Inc., 1981a). Because remediation is about 80% complete (Nolan, 1992b), much of this contamination is no longer present.
Ross et al. (1988) examined the toxicity of elutriates of Waukegan Harbor sediments to algae, bacteria, duckweed, lettuce, millet, and protozoans. Although lettuce and duckweed appeared resistant, the other tests showed toxic effects. Unexpectedly, there was no apparent correlation between PCB concentrations and toxic response, and samples from some areas with low levels of PCBs had high toxicity levels. This finding suggested that other pollutants were involved (Ross et al., 1988).
In a follow-up study, Risatti et al. (1990) examined the concentrations of other chemicals in the sediments and tried to correlate them with toxicity. Of the inorganic compounds (Table 5), the concentrations of cadmium, copper, lead, and zinc were elevated in at least some samples. Cadmium, lead, and zinc were elevated in Slip 1, and their source is unknown. Copper was elevated in Slip 3, and it could have come from the anti-fouling bottom paint used to keep boat hulls clean. Manganese and iron were also elevated in at least some of the samples. The elevated levels of cadmium, copper, iron, lead, manganese, and zinc are not site related. Risatti et al. (1990) also analyzed two samples from Slip 3 for organic priority pollutants (Table 6). One of the samples showed evidence of many organic compounds, including PCBs, PAHs, and phthalates. The concentration of polychlorinated dibenzofurans in the sediments is unknown. Because many factors affect the toxicity of chemicals in soil and therefore in sediments (discussed in the Health Effects section of this document), it is difficult to determine what levels of contamination pose a health hazard. Consequently, aside from PCBs, which have been found in fish, it is uncertain which chemicals in the sediments are currently at levels of health concern.
d. Surface Water
Harris (1982) reported that over a 28-day period (dates unknown), the level of PCBs in the water of Slip 3 ranged from 2.7 to 5 parts per billion (ppb). In water samples collected in May 1979, Thomann and Kontaxis (1981) found PCB levels ranging from about 6 ppb in the inner harbor to less than 0.1 ppb in the lake just offshore from the harbor. The concentrations in the inner harbor and Slip 3 were at levels of concern (health criterion = 0.45 ppb). In the harbor, the concentrations varied by about 1.5 to 2 orders of magnitude with time, and about 60% of the PCBs were dissolved. However, in the open lake, only about 40% of them were dissolved (Thomann and Kontaxis, 1981). The levels of other compounds (e.g., cadmium [not site-related], PAHs, and polychlorinated dibenzofurans) in the water of Waukegan Harbor are unknown.
By stirring up contaminated sediments, remediation and ship traffic may increase the concentrations of PCBs and other chemicals in the water column of Waukegan Harbor.
2. North Ditch
The concentrations of contaminants in the air at the North Ditch have not yet been measured. Remediation may liberate volatile chemicals and contaminated dust. PCBs are the only known contaminants at the North Ditch (air concentrations unknown), and other possible compounds (e.g., PAHs, polychlorinated dibenzofurans) have not been investigated.
The concentrations of PCBs or any other possible contaminants (e.g., polychlorinated dibenzofurans) in any fish of the North Ditch are unknown. It is questionable whether the North Ditch contains a sustained fish population, and the carp reported in it could have been transient.
The quality of the groundwater under the North Ditch is unknown; however, considering the extent of soil PCB contamination, it is proabably polluted.
d. Sediments and Soil
North Ditch areas contaminated with more than 20, 50, 500, and 5,000 ppm of PCBs are shown in Figures 4a to 4d, respectively. Soil concentrations of up to 137,100 ppm of PCBs have been found in the North Ditch, with contamination sometimes occurring to a depth of about 25 feet. In the Crescent Ditch, PCBs have pooled about 20 feet deep at the top of the silt/silty clay layer, but some PCBs have penetrated the layer. Surface PCB concentrations are unknown. About 160,000 cubic yards of soil (including the Parking Lot Area) were contaminated with more than 50 ppm of PCBs (Table 4). Mason and Hanger-Silas Mason Company, Inc. (1981a) estimated that between 500,000 and 1,500,000 pounds of PCBs were present in the North Ditch plus Parking Lot Area, with one estimate given in Table 4. The concentrations of other chemicals (e.g., PAHs, polychlorinated dibenzofurans) in the sediments and associated soil of the North Ditch are unknown.
e. Surface Water
In 1979, the measured average water concentration of PCBs in the North Ditch was about 7 ppb, with peak values of 80 to 160 ppb during rainfall events (Thomann and Kontaxis, 1981). The levels of any other possible or probable contaminants (e.g., PAHs, polychlorinated dibenzofurans) are unknown. Because remediation is now about 80% complete (Nolan, 1992b), water concentrations in the North Ditch may now be lower.
3. Parking Lot Area
The concentrations of chemicals in the air of the Parking Lot Area are unknown. Because the parking lot itself is paved, any contaminants in the air above it (e.g., PAHs, oil, or grease) would have to come from cars or other areas of the site. Some chemicals, however, could volatilize from the grassy portion of the Parking Lot Area, and remediation could liberate volatile chemicals and dust. PCBs are the only known chemicals of concern at this part of the site (air concentrations unknown), and any other possible chemicals (e.g., PAHs, polychlorinated dibenzofurans) have not been investigated.
The groundwater quality under the Parking Lot Area is unknown. Because of the high PCB levels in the soil, it is likely contaminated.
In the Parking Lot Area, PCB concentrations of up to 10,000 ppm are present, and these chemicals were found down to a depth of 9 feet at one location. The areas with PCB concentrations of more than 20, 50, 500, and 5,000 ppm are shown in Figures 4a to 4d, respectively. The amount of contaminated material and PCBs in the Parking Lot Area are given in Table 4. The concentrations of chemicals other than PCBs (e.g., PAHs and polychlorinated dibenzofurans) are unknown. In the grassy part of the Parking Lot Area, contaminants might be near the soil surface; however, in the paved portion, they are covered.
d. Surface Water
Any surface water in the Parking Lot Area would be from precipitation and would therefore be transient. The quality of any such water is unknown. In the paved portion of the Parking Lot Area, precipitation cannot contact contaminated soil. In the grassy part, the sandy soil would minimize runoff and promote infiltration, minimizing the occurrence of surface water.
4. New Slip
The air quality at the New Slip is unknown.
There are 4 monitoring wells at the New Slip. Two shallow ones are screened at 12.5 to 17.5 feet, and two deeper ones are screened at 23 to 28 feet. The results of one sampling date are available for each of these wells, (Table 7). While the sampling date are not reported, the laboratory reported the data October 11 to October 19, 1989. Only 2-methylnaphthalene and naphthalene were found in the shallower wells, with high concentrations of naphthalene. In the deeper wells, high concentrations of 2,4-dimethylphenol, 2-methylphenol, 4-methylphenol, and phenol were found. The high concentrations of the contaminants required that the samples be diluted for analysis, which resulted in high detection limits. This dilution might have prevented the detection of other chemicals, which could have been present at lower concentrations. The concentrations of dimethylphenol, 2-methylphenol, and phenol were at levels of health concern, and the toxicological information for 2-methylnaphthalene and 4-methylphenol were insufficient to eliminate them as chemicals of concern.
In 1989, six soil borings were made in the New Slip area, and one of them had high concentrations of PAHs (Barr Engineering Company, 1991). Further borings in the contaminated area found high concentrations of PAHs (anthracene, benz(a)anthracene, benzo(k)fluoranthene, benzo(a)pyrene, chrysene, fluoranthene, phenanthrene, and pyrene); other semivolatile organic compounds; and volatile organic chemicals (Tables 8 and 9). This contamination is apparently restricted to the site of the former coke plant and wood treatment facility, and other areas of the OMC property are not affected (Nolan, 1992a). In general, the concentrations of semivolatile compounds were higher at a depth of 5 feet than in deeper layers (Table 8). However, phenol, which is more volatile, was higher in the 23.5 to 26 foot layer. Table 9 contains a more detailed stratification, but samples at different depths are generally from different borings and the concentrations varied considerably between boreholes. Consequently, the data cannot be used to refine the spatial distribution of the contaminants. Concentrations of metals were not elevated above background levels, but many organic compounds were found. In general, the concentrations of chlorinated organic compounds were low, while those of nonchlorinated ones were higher. It is unknown if surface contamination or PCBs are present at the New Slip. Because surface concentrations are unknown, it is uncertain which chemicals might currently be at levels of health concern.
d. Surface Water
Any surface water at the New Slip would be from precipitation and would be transient. The quality of any such water is unknown. Once the New Slip is constructed, it will become part of Waukegan Harbor.
5. OMC Facilities
Industries must report air, water, and land emissions of specified quantities of more than 300 toxic chemicals to the EPA. The Toxic Release Inventory (TRI) database contains information on such emissions. TRI data (1991) indicate that the OMC plants emitted reportable quantities of aluminum dust or fumes, aluminum oxide, 1,1,1-trichloroethane, and trichloroethylene for 1987 to 1989 (Table 10). The airborne concentrations of these chemicals, however, are unknown.
1. Lake Michigan
The air quality over Lake Michigan is unknown. Contaminant concentrations are probably lower than those on site, and they should diminish with distance from the OMC property and Waukegan Harbor.
Harris (1982) reported PCB levels in several types of fish from Lake Michigan for 1972 to 1981 (Table 2). It is unknown whether the samples were whole fish or filets. Harris (1982) found that PCB levels were slightly elevated in the Groups A and F fish (Table 5).
For 1989, limited data are available for PCB levels in the filets of some Lake Michigan fish (Table 11). None of them, including rainbow trout from the New Waukegan Harbor immediately south of the old contaminated one, contained high levels of PCBs. Because most of the fish were grouped into composite samples with fish from other locations, the spatial distribution of PCB concentrations in fish around Waukegan Harbor cannot be examined. The levels of polychlorinated dibenzofurans have not yet been measured in Lake Michigan fish.
Bloater chubs are harvested commercially from Lake Michigan, but they are not sought by sport anglers. From 1975 to 1981, bloater chubs were caught off of Waukegan Harbor and analyzed for PCBs. In 1976, the composite sample had 8.3 ppm of PCBs; however, in the other years, the fish had under 5 ppm of PCBs (Harris, 1982).
One sample of surficial sediment collected about 400 meters (around 1,300 feet) offshore from the mouth of Waukegan Harbor had approximately 0.1 ppm of PCBs. In the open lake, sediment PCB concentrations vary from 0.01 to 0.1 ppm (Thomann and Kontaxis, 1981). The concentrations of polychlorinated dibenzofurans in the sediments have not yet been measured.
d. Surface Water
After 15 years of high PCB discharge from OMC, Thomann and Kontaxis (1981) estimated that, in 1970, the concentration of PCBs in Lake Michigan reached a peak of 7 to 15 ppt (parts per trillion = nanograms per liter). However, because these and other PCB data were from point sources, they do not provide clear information about the distribution of these chemicals throughout the lake. Concentrations would have been higher near sources and would have decreased as distance from the source increased. The estimated PCB concentrations are below levels of health concern for consumption of the water (health criterion = 450 ppt = 0.45 ppb).
Thomann and Kontaxis (1981) used a model based on actual measurements to estimate the distribution of water PCB concentrations in and around Waukegan Harbor (Figure 11). According to the EPA (1981), the PCB levels in Lake Michigan range from 5 to 10 ppt in the open lake and are typically up to 50 ppt near the shore. Consequently, the concentrations of PCBs in the water of Lake Michigan are below levels of health concern for drinking water. The concentrations of polychlorinated dibenzofurans in the water of Lake Michigan are unknown.
Because the city has many industries, at least one landfill with PCBs, and many busy roads, numerous sources of contamination are present and would likely complicate any off-site study. According to the TRI (1991), many industries in the site zip code emit reportable quantities of chemicals (Table 12); however, the airborne concentrations of these compounds are unknown.
Quality assurance/quality control (QA/QC) information was available only from the Barr Engineering Co. (1991) report that summarized Canonie Engineers' sampling data on the New Slip. In general, sampling at other parts of the site has been restricted to PCBs, and other possible contaminants (e.g., cadmium [not site-related], PAHs, and polychlorinated dibenzofurans) have been ignored.
The concentrations of chemicals in surface soil are unknown, so it is uncertain which ones are currently of health concern.
Much of the information used for this document came from USEPA files, reviewed June 6-8, 1990, and the Barr Engineering Co. (1991) report.
There are no apparent physical hazards at the site. Because public access to the OMC property is
restricted and the property is surrounded by a chain-link fence topped with barbed wire, trespassing is probably infrequent.
A hazardous chemical can affect people only if they contact it through an exposure pathway at a sufficient concentration to cause a toxic effect. Exposure requires a source, environmental transport media, point of exposure, route of exposure, and exposed population. Sources of contamination are discussed in the Environmental Contamination and Physical Hazards section of this report. The Environmental Pathways subsection contains a discussion of environmental transport media, and the Human Exposure Pathways subsection covers points of exposure, routes of exposure, and exposed populations. A pathway is complete if all of its components are present and people were exposed in the past, are currently being exposed, or will be exposed in the future. If parts of a pathway are absent, data are insufficient to determine whether the pathway is complete, or exposure could have occurred or could occur occur at some time (past, present, or future), the pathway is potential. Table 13 summarizes the exposure pathways at this site.
a. Waukegan Harbor
Chemicals can volatilize from the water surface of Waukegan Harbor. Wind and wave action could also produce airborne aerosols, which might contain contaminants. Volatilization from land sources is PCBs' major method of dispersal in the environment. PCBs have a fairly low vapor pressure (often under 0.000001 atmospheres). However, chlorinated hydrocarbons such as PCBs have surprisingly high volatilization rates from water because they are relatively insoluble in it and tend to partition into the air or deposit onto solid materials. The atmosphere contains PCBs as particulates (adsorbed onto particles) or as vapor. They are removed from the air by three mechanisms: (1) precipitation (rain and snow); (2) dry deposition of particles, especially near sources; and (3) vapor exchange with bodies of water (Mason and Hanger-Silas Mason Company, Inc., 1981b). Assuming a PCB concentration of 1 ppb in the water, a water temperature of 15oC, and a wind speed of 1.62 meters per second (3.62 miles per hour), Mason and Hanger-Silas Mason Company, Inc. (1981b) estimated that 3.33 pounds per month would be emitted into the air from Waukegan Harbor. The volatilization rate would be lower in the winter and spring, when the water is colder. The amount emitted from the harbor is considerably greater than that deposited by precipitation and dry deposition, which has been estimated to be 0.0025 pounds per month (Mason and Hanger-Silas Mason Company, Inc., 1981b).
b. North Ditch
At the North Ditch, chemicals can volatilize from the water or soil. In addition, potentially contaminated aerosols and dust could be liberated from the water and soil surfaces, respectively. Much of the contamination is probably below the water table, and the resulting moisture should inhibit dust production during remediation.
c. Parking Lot Area
In the Parking Lot Area, the pavement in the parking lot itself would minimize volatilization and stop dust production from this portion of the site. Remediation will probably increase dust production and volatilization. Below the water table, moisture should inhibit dust production during clean-up.
d. New Slip
Volatile chemicals and dust could become airborne from the soil of the New Slip. The concentrations of VOCs are lower 5 feet under the surface than at 24 to 26.5 feet, but the reverse is true for the less volatile chemicals. Some of the VOCs in the soil nearer the surface could have been lost through volatilization.
During remediation, the exposure of subsurface soil to the air will increase volatilization and liberate potentially contaminated dust. Much of the contamination is probably below the water table, and the resulting moisture should reduce dust production.
e. Off-site Transport
Airborne compounds liberated from any of the contaminated areas could be carried off site into Waukegan or over Lake Michigan. with vapors, aerosols, or contaminants adsorbed onto airborne particles. When the lake is cooler than the land, air tends to move from the water to the land, and contaminants would be transported toward Waukegan. When the lake is warmer than the land, air tends to flow from the land out onto the lake, which would transport contaminants out over Lake Michigan. Moderate to strong winds can override this lake effect.
For all sources, the total deposition of PCBs into Lake Michigan is about 7,000 kilograms (about 15,400 pounds), 0.7 pounds per square mile per year (Mason and Hanger-Silas Mason Company, Inc., 1981b ). Thus, before remediation, the volatilization rate of PCBs from Waukegan Harbor, estimated to be 3.3 pounds per month or 39.6 pounds per year (Mason and Hanger-Silas Mason Company, Inc., 1981b ) probably contributed little to the total PCB input of Lake Michigan. However, it could have contributed measurably to the PCB input near the harbor.
2. Bioaccumulation and Biomagnification in the Food Chain
If an organism absorbs a chemical faster than the chemical is eliminated from its body, it will accumulate the compound in a process called bioaccumulation. In the food chain, animals eat large quantities of their prey or plants, and for compounds that bioaccumulate, this can cause higher concentrations in organisms at successive levels of the food chain. For example, zooplankton, which eat phytoplankton have higher concentrations of bioaccumulating chemicals than the levels in their food. The fish which eat zooplankton have even higher levels, and the large fish which eat smaller ones have still higher concentrations. This phenomenon is called biomagnification. Because they are soluble in fat, relatively insoluble in water, and not easily broken down by the body, PCBs exhibit bioaccumulation and biomagnification. Fish and other organisms can accumulate these chemicals by absorption from the water column; contact with sediments, in-place or suspended in the water column; and the process of the food chain (U.S. Army Corps of Engineers, 1986 ). PCBs and heavy metals can be absorbed from suspended sediments that accumulate on gill filaments (U.S. Army Corps of Engineers, 1986). The exposure to suspended sediments would be highest near the shore and would be increased by dredging, including dredging during remediation. However, turbidity caused by dredging in Waukegan Harbor during remediation would likely displace fish, minimizing this exposure (U.S. Army Corps of Engineers, 1986 ). According to the U.S. Army Corps of Engineers (1986), dredging would increase the bioavailability of contaminants and decrease dissolved oxygen in the water. In addition to dredging, ship traffic can stir up sediments and increase the bioavailability of contaminants.
Many factors influence the uptake and bioaccumulation of PCBs and other chemicals by fish and other organisms. At Waukegan Harbor, a permanent resident fish should have higher PCB levels than a transient fish. Bottom feeders, through frequent contact with and incidental consumption of sediments, tend to accumulate PCBs readily. Older and larger fish would be expected to have more PCBs, while fast-growing species should have lower concentrations. Conversely, long-lived fish would be expected to have higher levels of PCBs. Because PCBs accumulate in fat, fish with more fat should accumulate higher concentrations of PCBs. Fish that live in cold water have a slower metabolism and consequently cannot eliminate PCBs as rapidly from their bodies as fish in warmer water can; consequently, they tend to accumulate high levels of these compounds.
Of the fish caught in the Waukegan area, the Group A fish--coho and chinook salmon and brown and rainbow trout--are fast-growing, have short life spans, migrate considerably (Harris, 1982), and would be transient residents of the harbor. This should result in a lower PCB uptake for these fish; however, they have a higher fat content than other lake fish, which causes increased bioaccumulation (Harris, 1982). These fish feed on alewife, smelt, and other forage fish, which brings them into near-shore areas. In spring or fall, they migrate into tributaries for spawning (Harris, 1982). If these behaviors take them into contaminated areas, increased PCB concentrations are likely. If dredging is done at this time, it could lead to increased PCB levels in these fish.
The Group B fish--black and white crappie, largemouth bass, shiners, sunfish, and yellow perch--generally inhabit warm, slow-moving water and eat crustaceans, insects and small fish. They generally live in sheltered, near-shore environments and can accumulate high PCB concentrations (Harris, 1982).
Alewife is the only Group C fish. Alewife primarily eat zooplankton and generally live in deep, open-lake waters. However, they may move inshore seasonally (Harris, 1982). These fish, therefore, would be transient residents of Waukegan Harbor. This could lead to occasional exposure to high PCB concentrations. The deep, open water they inhabit would then slow their elimination of these contaminants. Because alewife are important prey of larger fish, even moderate contamination in them could cause high PCB concentrations in their predators (e.g., lake trout and salmon).
The Group D fish--brown and black bullhead, carp, and white suckers--are bottom-feeders that inhabit sluggish, warm waters (Harris, 1982). They can accumulate very high PCB levels.
The Group E fish--bloater chub, lake herring, and whitefish--inhabit deep, offshore areas and eat plankton (Harris, 1982). Because they are relatively low on the food chain, they should have lower PCB contamination than the larger fish that prey on them have. However, the cold water these fish inhabit would slow their elimination of PCBs and promote bioaccumulation, and, as is the case with Group C fish, contamination of the Group E ones could cause high PCB concentrations in their predators.
Lake trout is the only Group F fish. Lake trout inhabit deep, cold water most of the year and feed mostly on alewife. They mature in about 7 years (Harris, 1982). These factors enable lake trout to accumulate high PCB concentrations.
There have been several experiments to examine the PCB uptake of Group B fish (bluegill and/or yellow perch) exposed to Waukegan Harbor water or suspended harbor sediments (Table 14). In 7 days, yellow perch exposed to suspended sediment showed higher levels of PCBs than fish in a control group showed. In two studies, the exposure of bluegill and yellow perch to water in Waukegan Harbor for 28 to 30 days resulted in high PCB levels. In one of these experiments, fish kept in the harbor for 30 days were moved offshore into Lake Michigan near the Waukegan waterworks. The fish still had high PCB levels after 80 days at the latter location, but not as high as when they were moved (Table 14). These experiments indicate that, after remediation is complete, it will take a considerable amount of time for fish PCB levels to decline to acceptable levels and fish of the open lake that come inshore to spawn or feed may accumulate high PCB concentrations, which may persist at levels of concern for some time after they return to the open lake. Coho and chinook salmon, brown and rainbow trout, and alewife exhibit this behavior. The contamination of alewife could cause increased PCB levels in off-shore predators, including lake trout and salmon.
Harris (1982) reported the results of laboratory exposure of flathead minnows to North Ditch water (Table 14). When adult fish were used, the North Ditch water contained 10 to 30 ppb of PCBs, while the control water from Lake Michigan had less than 0.1 to 0.3 ppb of PCBs. The fish exposed to North Ditch water in that experiment accumulated very high levels of PCBs. Embryonic fish exposed to 10 to 23 ppb of PCBs in North Ditch water accumulated high levels of these chemicals, but not as high as those in the adult fish experiment. The control fish were generally exposed to less than 0.01 ppb of PCBs (Harris, 1982). Flathead minnows would not be considered food for humans, but they are likely food of larger fish, which could then become contaminated with high levels of PCBs after eating contaminated minnows.
PAHs are not very water soluble, and they can accumulate in aquatic organisms, although to a much lesser extent than PCBs. Bioconcentration factors for PAHs in fish and crustaceans range from about 100 to 2,000 (Eisler, 1987; cited in ATSDR, 1990). In animals exposed to estuarine sediments, approximate tissue to sediment concentration ratios for benzo(a)pyrene were 0.6 to 1.2 for amphipods, 0.1 for clams, and 0.05 for fish and shrimp (Varanasi et al., 1985; cited in ATSDR, 1990). Consequently, its uptake from sediments is low. Unlike PCBs, PAHs are easily eliminated from the bodies of animals, with half-lives in fish of less than 2 to 9 days (Niimi, 1987; cited in ATSDR, 1990). Consequently, PAHs do not biomagnify in the food chain (Eisler, 1987; cited in ATSDR, 1990), and fish that leave contaminated areas should eliminate these compounds fairly rapidly. Slightly elevated PAH concentrations were found in one sediment sample from Slip 3 but not in another sample. More data are needed to determine whether the possible bioconcentration of PAHs by fish of Waukegan Harbor is of concern.
Cadmium (not site-related) was somewhat elevated in some sediment samples from the harbor, but its water concentrations are unknown. Studies indicate that cadmium levels in sediments are at least one order of magnitude lower than those in the overlying water (ATSDR, 1992). This element readily accumulates in freshwater organisms at concentrations hundreds to thousands of times that in the water, and it can also biomagnify in the food chain (ATSDR, 1987a). It is unknown whether cadmium levels in the harbor are high enough to accumulate to significant levels in fish.
Chemicals could also accumulate in other aquatic organisms or waterfowl.
Most of the OMC property is on a peninsula surrounded by Lake Michigan and Waukegan Harbor. Warzyn Engineering (1979) made borings at 9 locations on the property and found that the upper layer is 2 to 8.5 feet of fill, which is mostly sand, but also sometimes contains ash, brick chips, cinders, clay, concrete fragments, gravel, organic material, and silt. This highly permeable material would tend to inhibit runoff and promote infiltration. The surficial layer is underlain by sand with a trace of silt and clay, and, occasionally, some gravel. Under this layer, at a depth of 23 to 30.5 feet, is silt of uncertain thickness. Other investigators have characterized this layer as silty clay (Mason and Hanger-Silas Mason Company, Inc., 1981a) or clayey silt (USEPA, 1981). Mason and Hanger-Silas Mason Company, Inc. (1981a) found that the permeability of this layer is about 0.0000001 centimeters per second, but it can contain some gravel, sand, and thin organic seams. Sand and gravel layers would tend to increase the lateral transport of contaminants. PCBs have pooled on top of the silty clay (Nolan, 1992b).
The groundwater under the OMC property has not been well investigated. Much of the land is on a relatively flat peninsula, there is apparently little hydraulic gradient, and groundwater movement is slow. On July 25, 1979, Warzyn Engineering, Inc. (1979) found that the water elevation in on-site wells ranged from 579.8 to 584.1 feet, with water levels in 10 of 11 wells being within one foot of each other. According to Roberts (1982), the hydraulic gradient near Waukegan Harbor is only 0.0007 feet per foot. In general, water moves slowly to the lake or harbor, with all of it ultimately going into Lake Michigan. This movement, although slow, could carry contaminants into Lake Michigan. Two borings were made through the clay layer during the design phase. They showed that near the lake, the groundwater gradient is upward (i.e., water tends to move upward). On the western edge of OMC, groundwater tends to move downward (Nolan, 1992b).
b. North Ditch
The floor of the North Ditch is sand, so water can flow freely from the ditch into the groundwater and vice versa. In the East-West portion, the direction of flow depends on the water level in the ditch. Water flows from the ditch into the groundwater when the water level in the ditch is high. It flows in the opposite direction when the water level in the ditch is low (Mason and Hanger-Silas Mason Company, Inc., 1981a). Factors affecting the water level in the ditch are discussed in the Surface Water subsection.
c. Parking Lot Area
Because the parking lot itself is paved, precipitation cannot infiltrate and produce leachate. Groundwater in this area would originate from the surrounding area. In the grassy area, however, precipitation can infiltrate into the soil. The flow of groundwater specifically in the Parking Lot Area has not been investigated.
d. New Slip
Groundwater flow at the New Slip should be typical of that on the rest of the peninsula. After the New Slip is constructed, it will become part of Waukegan Harbor.
4. Surface Water
a. Waukegan Harbor
In Waukegan Harbor, water flows outward into Lake Michigan near the surface and from the lake into the harbor along the bottom. The deep flow carries sediments, which are deposited in the harbor channel. Slip 3, however, is not affected by sediments from Lake Michigan. Its siltation probably comes from overland flow and storm outlets, which carry dust and dirt accumulated from parking lots and streets (Shahabian, 1982). In addition, eroded soils could discharge into the harbor and both those soils and possibly runoff from roof drains could discharge into the North Ditch. Using average values for U.S. cities and a study in Milwaukee, Shahabian (1982) estimated that this overland flow contributes 290,000 to 560,000 pounds of sediments per year to Slip 3. Assuming an equal distribution, this would result in the accumulation of 0.5 to 0.9 of an inch of sediment per year. At this rate, it would take 13 to 24 years to accumulate 1 foot of sediment. Similarly, use of the Universal Soil Loss Equation gives an estimate of 12 to 24 years to accumulate 1 foot of sediments (Shahabian, 1982). If the contaminated sediments in the harbor become covered by nonpolluted material, this will decrease the suspension of contaminated sediments, the concentrations of PCBs in the water, the volatilization of PCBs from the water surface, and the export of contamination into Lake Michigan.
Dredging and ship traffic could stir up sediments, increasing the concentrations of chemicals in the water column. The U.S. Army Corps of Engineers (1986) reported that PCBs, lead, and mercury in the harbor are strongly bound to fine-grained sediments. The release of PCBs from these particles is generally negligible, and their concentrations in the water column are dependent on the presence of suspended solids. Consequently, the success of any remediation method depends on the successful containment of fine sediments (U.S. Army Corps of Engineers, 1986 ). However, Thomann and Kontaxis (1981) found that 60% of the PCBs in Waukegan Harbor are dissolved. This suggests that the appraisal of the Army Corps of Engineers (1986) might not be correct.
Using a mathematical model calibrated with chloride, resuspended solids, and dye, Thomann and Kontaxis (1982) estimated the transport of PCBs into Lake Michigan. They estimated that during 1955 to 1971, when PCBs were used at OMC, between 4,200 and 26,000 kilograms (9,200 to 58,600 pounds) per year were discharged from the harbor into the lake, with a best estimate of 15,000 kilograms (33,000 pounds) per year. This transport, coupled with that of the North Ditch, might have contributed about 50% to 90% of the Lake Michigan water concentrations and fish levels of PCBs and might have accounted for from three to five times the present PCB input to Lake Michigan as all other sources combined. Before remediation, the net export of PCBs from the harbor to the lake was about 10 kilograms (22 pounds) per year. This input was less than 1% to 2% of the present PCB input to the lake from all sources, about 1,400 to 5,600 kilograms or 3,100 to 12,000 pounds of PCBs per year; Thomann and Kontaxis, 1981). By stirring up sediments, remediation could temporarily increase the export of contaminants from the harbor. However, the completion of remediation will stop this output of pollutants.
In the past, dredged sediments from Waukegan Harbor were dumped into Lake Michigan, and this could have contributed to pollution of the lake. However, these sediments were from the lower harbor, which has lower PCB concentrations, and the dumping was done relatively infrequently. Consequently, this input into Lake Michigan might have been minor compared to other pathways.
b. North Ditch
The water level and flow in the North Ditch are influenced by Lake Michigan and the wind. Strong on-shore winds pile sand at the mouth of the ditch, sometimes closing it off. This decreases the discharge to the lake, and the water level in the ditch rises. The higher water causes the water to flow from the ditch into the groundwater. Sometimes, sand must be removed from the mouth of the ditch to prevent flooding. On the other hand, strong off-shore winds tend to keep the mouth of the ditch open, contributing to free flow and lower water levels. The lower water level enables groundwater to enter the ditch (Mason and Hanger-Silas Mason Company, Inc., 1981a).
From March 13 to September 30, 1979, the U.S. Department of the Interior found that the flow of the North Ditch near its mouth ranged from 65,000 to 1,200,000 gallons per day, with an average of 350,000 gallons per day. During periods of low flow, the water of the North Ditch might not reach the lake, but might flow instead into the groundwater. The highest measured instantaneous peak discharge was 5.3 cubic feet per second, the equivalent of 3,500,000 gallons per day. A 5-year storm event of 3-hour duration would result in an estimated discharge of up to 75 cubic feet per second (Mason and Hanger-Silas Mason Company, Inc., 1981a), which would be the equivalent of about 50 million gallons per day.
The surface water of the North Ditch carries suspended sediments, which are discharged into Lake Michigan. From March 13 to September 30, 1979, about 5,100 pounds of sediments were discharged, almost one-third of it in March. The maximum daily load was about 450 pounds, and the average discharge was around 25 pounds. Peak sediment discharge from a 2-year storm was estimated to be about 250 pounds per hour, while that from a 100-year storm would be around 1,600 pounds per hour (Noehre and Graf, 1980). Consequently, storms can greatly increase the export of sediments and, hence, associated contaminants, from the North Ditch.
c. Parking Lot Area
In the Parking Lot Area, any surface water would come from precipitation and would be transient. Because the parking lot is paved, precipitation falling on it cannot become contaminated by the wastes. In the grassy area east of the pavement, the thick vegetative cover should minimize runoff, soil erosion, and, hence, the transport of contaminants by surface water. Furthermore, the sandy nature of the soil would promote infiltration and minimize runoff.
d. New Slip
At this time, any surface water at the New Slip would come from precipitation and would be transient. This water could carry any surface contaminants into Waukegan Harbor, but the sandy soil would minimize runoff and promote infiltration. Once the New Slip is constructed, it will become part of Waukegan Harbor.
The principal human exposure pathways are dermal absorption, inhalation, and ingestion. Dermal absorption can occur from contact with contaminated air, dust, groundwater, sediments, soil, or surface water. Exposure may also occur from the inhalation of dust or gases, as well as from the ingestion of dust, food, groundwater, surface water, or soil.
1. Dermal Exposure
a. Waukegan Harbor
Anglers, boaters, and other members of the public, as well as remediation workers and other on-site workers, could be exposed to contaminants in the water or sediments of Waukegan Harbor via dermal exposure. This could occur if chemicals contact the skin or soak into or adhere to clothing. About 3,500 people work around Waukegan Harbor, but it is not known how many of them contact water or sediments or how often they do it. Anglers and boaters could be exposed to surface water and bottom sediments. While boat anchors might pick up sediments and be cleaned by hand, anchoring in a busy harbor is unlikely. Baits and sinkers used for bottom fishing (carp, catfish) could become covered with sediments and could be cleaned by hand. Remediation workers likely have contacted and will contact sediments, and these exposure pathways are complete for them, but potential for others. Exposure via these pathways might have occurred in the past and might occur in the present or future.
b. North Ditch
People could be dermally exposed to contaminated dust, sediments, soil, or surface water at the North Ditch if chemicals contact the skin or soak into or adhere to clothing. On the eastern side of the site, children (especially) or adults could enter the North Ditch from the public beach and be dermally exposed to contaminants. Furthermore, beach-goers are generally barefoot and have a lot of exposed skin, which makes dermal exposure more likely. Maintenance and remediation workers could also be dermally exposed to contaminants along the North Ditch. Most of the contamination in the North Ditch is on OMC property, which is not readily accessible to the public. Remediation workers are the only people likely to contact potentially contaminated groundwater. Because the concentrations of pollutants in groundwater are unknown, this is a potential exposure pathway. All of the other pathways are complete (past, present, or future).
c. Parking Lot Area
Because public access in this area is restricted, contact by trespassers is probably infrequent. Exposure of OMC personnel is more likely. Because it is unknown whether vegetation is contaminated, this pathway is a potential one. People might have been exposed via vegetation in the past or might be exposed now or in the future. During remediation, on-site workers could be exposed to chemicals in soil and in vegetation. Remediation workers might experience groundwater exposure. The vegetation and groundwater pathways are potential ones, while the others are complete.
d. New Slip
At the New Slip, people might be dermally exposed to chemicals in dust or soil which contact the skin or adhere to clothing. Public access to the New Slip is restricted, and while trespassing might occur, it is probably infrequent. Consequently, dermal exposure is most likely for remediation workers and other on-site workers, and the former could also contact contaminated groundwater. Pollutants would have to be near the surface for dermal exposure to occur. It is unknown whether surficial contaminants exist, so for the past and present, dermal exposure to chemicals in soil is a potential pathway. During remediation (future for the new slip), the soil and groundwater pathways will be complete.
e. Other OMC Property
It is unknown whether surficial contamination is present on other OMC property. This must be established to determine whether additional dermal exposure might occur.
f. Off-Site Dermal Exposure
(1). Lake Michigan
Anglers, beach-goers, boaters, and swimmers could be exposed to chemicals in the sediments or surface water of Lake Michigan if the chemicals contact the skin or absorb into or stick to clothing. People using the Waukegan municipal water supply could be dermally exposed to chemicals from Lake Michigan water during such activities as showering. However, PCB levels in Lake Michigan are below levels of concern, and the concentrations of other contaminants are unknown. Consequently, these pathways are potential ones (past, present, future).
(2). North Ditch
The North Ditch crosses the public beach west of the site, and exposure to contaminated sediments or water along the ditch is most likely at this location. This pathway is complete (past, present, future); however, it is not known how often or how many beach-goers visit the North Ditch. Most of the contamination along the North Ditch is on OMC property, rather than on the public beach.
If the auxiliary water intake is used, people using the Waukegan municipal water supply may be dermally exposed to contaminants from the harbor during such activities as showering. However, this water would be diluted with that from Lake Michigan, and the auxiliary water intake is rarely used. Consequently, this potential pathway probably results in negligible exposure (past, present, future).
2. Inhalation Exposure
a. Waukegan Harbor
Anglers, boaters, remediation workers, and other on-site workers could be exposed to volatile chemicals or aerosols in the air over Waukegan Harbor. This pathway is complete (past, present, future).
b. North Ditch
People at the North Ditch could inhale volatile chemicals or dust. Particles over 5 microns tend to be deposited in the nasopharyngeal region and to be ingested. Particles 1 to 5 microns cannot penetrate deeply into the lungs, but are generally deposited in the bronchi, removed from the lungs by cilia, and ingested. Particles less than 1 micron in size, however, can penetrate deeply into the alveoli of the lungs and cannot be easily removed. The public would most likely have inhaled or continue to inhale contaminants from the North Ditch near the beach (past, present, future). Maintenance workers and remediation workers (past, present, future) might also have been exposed or might be exposed to contaminants via inhalation. Because the airborne concentrations of pollutants are unknown, these pathways are potential ones.
c. New Slip
Remediation workers (future) and other on-site workers (past, present, future) could have been exposed or could be exposed to volatile chemicals and contaminated dust via inhalation. Trespassing is probably infrequent, so exposure to the public is likely negligible. Remediation will likely increase the production of volatile chemicals and airborne dust. Because the airborne concentrations of chemicals are unknown, these pathways are potential ones.
d. Parking Lot Area
People could inhale volatile chemicals liberated from the soil east of the paved area (past, present, future). Because public access is restricted, the exposure of trespassers would probably be infrequent. On-site workers and people using the parking lot) could be exposed to volatile compounds, and, during remediation, they could also inhale contaminated dust. Because the airborne concentrations of contaminants are unknown, this pathway is a potential one.
e. Off-Site Exposure
Anglers, boaters, swimmers, beach-goers, off-site workers, and people in Waukegan could have inhaled or could inhale volatile chemicals or contaminants in aerosols or dust (past, present, future). People on the public beach could inhale contaminants from the North Ditch or other parts of the site. Remediation could have increased and might yet increase the concentrations of airborne contaminants in these locations. Because the airborne concentrations of pollutants are unknown, these pathways are potential ones.
People using the Waukegan municipal water supply could inhale Lake Michigan or Waukegan Harbor contaminants that are liberated during such activities as showering. For Lake Michigan, PCBs are below levels of health concern, but the concentrations of other chemicals are unknown. Consequently, this is a potential pathway. Exposure from this potential pathway is probably negligible.
3. Ingestion Exposure
a. Waukegan Harbor
The primary concern is the exposure to PCBs via the consumption of contaminated fish. This has been, is, and will continue to be a completed pathway. PCBs in many types of fish from Waukegan Harbor are at levels of health concern. People eating fish from the harbor might also be exposed to cadmium (not site-related), PAHs, and polychlorinated dibenzofurans, but it is uncertain whether they are at levels of health concern. While the harbor itself was partially posted with warnings against eating its fish, some people have ignored the signs. Furthermore, the removal of the warning signs by vandals during October 1992 might have given people the false impression that fish from the harbor are uncontaminated and suitable for consumption. This could increase exposure to contaminated fish. Furthermore, by stirring up polluted sediments, remediaton might increase water PCB concentrations in water and therefore in fish. It is unknown how many people eat fish from Waukegan Harbor or how often they and their families eat these fish. It is also unknown what types of fish are most frequently caught and consumed from the harbor. In general, the class B and class D fish are likely to be more common in the harbor, and they might be eaten more frequently. This is of concern because these fish generally have the highest PCB concentrations. The median fish consumption of people eating Lake Michigan fish is 34 pounds per year, and some people eat more than 250 pounds per year (Michigan Department of Public Health, date unknown).
While waterfowl could potentially accumulate PCBs and other chemicals, hunting is not permitted in the harbor. Waterfowl of the harbor are probably accustomed to being fed by humans, and might therefore not migrate to areas where hunting is likely. Consequently, this potential pathway could be incomplete.
While exposure via the consumption of contaminated surface water might occur, it is probably infrequent within the harbor itself. Anglers, boaters, remediation workers, and other on-site workers might have ingested or might ingest contaminated sediments or chemicals in inhaled aerosols (past, present, future). These are potential pathways.
b. North Ditch
There are carp in the North Ditch, but the North Ditch is probably not used frequently for fishing. It is also questionable whether it has a sustained fish population. Consequently, in this area, the exposure of people via the consumption of contaminated fish is probably negligible, and this pathway will not be considered further. Beach-goers could ingest contaminated dust along the North Ditch. Some young children (usually under 6 years old) eat dirt (pica behavior) and could eat contaminated soil or sediments, as well as potentially contaminated vegetation. Non-pica children and adults could also ingest soil incidentally. These pathways are complete for past, present, and future scenarios. However, most of the contamination along the North Ditch is on OMC property, which is not readily accessible to the public.
c. Parking Lot Area
Because the parking lot is paved, subsurface contamination cannot be ingested at this location. Furthermore, with the thick layer of grass east of the paved area, the ingestion of dust is unlikely. During remediation, however, workers could ingest contaminated dust. Consequently, this pathway was, is, and will be complete only during remediation. Because public access is restricted, the exposure of trespassers in the Parking Lot Area should be infrequent.
d. New Slip
Remedial workers and other on-site workers could ingest contaminated dust or soil at the New Slip. Because public access is restricted, their exposure at the New Slip is probably infrequent. Because surface soil concentrations are unknown, for the past and present, these pathways are potential ones, but they will be complete during remediation. Remediation will probably increase the production of airborne dust. However, much of the contamination is below the water table, and the resulting moisture should inhibit the production of airborne dust.
e. Off-site Exposure
(1). Lake Michigan
Consumption of fish contaminated with PCBs is the primary concern. This pathway is complete for the past, present, and future. The Illinois Department of Conservation (IDOC) estimated that shoreline and breakwater anglers spent about 89,000 hours during 21,000 fishing trips near the mouth of Waukegan Harbor in 1990. Boats operating out of Waukegan Harbor spent about 37,000 hours in Lake Michigan during 6,900 trips. The IDOC does not have any estimates of the number of people who eat fish from Lake Michigan or how often they do it (Trudeau, 1992).
While waterfowl could potentially be contaminated by PCBs and other chemicals, hunting is not allowed in the harbor or immediate vicinity. The area south of the harbor is mostly developed, and that to the north is too close to industrial facilities and other buildings for hunting to be permitted.
Hunting is also not allowed at Illinois Beach State Park. Consequently, the consumption of potentially contaminated waterfowl taken near the harbor is unlikely. Therefore, this pathway is not complete near the site but is potentially complete away from it.
People might ingest contaminants during swimming, but other consumption of raw lake water is probably infrequent.
People in Waukegan could have ingested or could ingest inhaled contaminated dust or aerosols liberated by the different parts of the site (past, present, future). This exposure would be less extensive than that of on-site people. Furthermore, because of the large number of contaminant sources in the city, any such exposure from site contaminants would probably be hard to determine. Consequently, this is a potential pathway.
People using the Waukegan municipal water supply likely drink the water. PCBs in Lake
Michigan water are below levels of health concern, but the concentrations of other potential
contaminants are unknown. Consequently, this is a potential exposure pathway (past, present,
future). While the concentrations of PCBs in the water of Waukegan Harbor can reach levels of
concern, the auxiliary water intake is used infrequently and PCBs might be diluted to below
levels of health concern by being mixed with water from Lake Michigan. Consequently,
exposure from this potential pathway is probably negligible.
1. Chemicals of Concern
a. Waukegan Harbor
The primary chemicals of concern in Waukegan Harbor are PCBs, with ingestion via the consumption of contaminated fish being the most important exposure pathway. While PAHs and bis-2-ethylhexyl phthalate were elevated in one sediment sample, their concentrations in other media are unknown. Thus, both the extent of exposure to these compounds and the likelihood that they exist at levels of health concern remain unknown. It is not known whether polychlorinated dibenzofurans are present in fish at levels of health concern. While levels of some heavy metals are slightly elevated in the sediments, the levels are not considerably high. With the possible exception of cadmium, human exposure to them is probably infrequent. It is unknown whether cadmium in the sediments has led to fish contamination at levels of health concern. Cadmium is not thought to have come from OMC, but its possible source is unknown. The concentrations of other metals are below levels of human health concern.
b. North Ditch
The only known chemicals of concern in the North Ditch are PCBs. The concentrations of any other possible contaminants are unknown. Exposure to contaminants could occur via dermal contact with dust, groundwater, sediments, soil, and surface water; inhalation of dust and volatile chemicals, or ingestion of biota, dust, sediments, soil, and surface water.
c. New Slip
The primary chemicals of concern at the New Slip are phenol and PAHs. While other VOCs and metals are present, their concentrations are below those of human health concern. Exposure to contaminants could occur via dermal contact with dust, groundwater, and soil; inhalation of dust and volatile chemicals or ingestion of dust and soil.
d. Parking Lot Area
The only known chemicals of concern in the Parking Lot Area are PCBs. The concentrations of any other possible contaminants are unknown. Exposure to chemicals might occur via dermal contact with dust, groundwater, soil, and vegetation; inhalation of dust and volatile chemicals; or ingestion of dust and soil).
e. Off-site Contamination
PCB contamination of Lake Michigan fish is of concern. These fish also contain other chemicals, including chlorinated hydrocarbon insecticides, which did not originate from OMC. This background contamination adds to the health concerns about eating PCB-contaminated fish.
2. Soil and Sediments
Many factors affect the adsorption of chemicals by soil, and, hence, sediments. These factors include clay content and type, cation exchange capacity, moisture level, organic matter content, pH, soil particle size distribution, and temperature, as well as the water and octanol solubilities of the compound of concern (Harris, 1972; Bailey and White, 1970; Harris, 1966). Chemicals that are tightly bound by soil are not easily absorbed by organisms, and this greatly reduces their toxicity. For example, Harris (1966) found that soil organic matter had a large effect on insecticide activity in crickets. Heptachlor, diazanon, Memacide, DDT, and parathion were 209, 283, 546, 965, and 1132 times less toxic, respectively, in a muck soil with 64.4% organic matter than in quartz sand (Harris, 1966). This occurred because organic matter adsorbs compounds with low water solubility (e.g., many insecticides, PCBs), reducing their bioactivity. Soils with increased clay content and cation exchange capacity (primarily affected by clay and organic matter content) bind cations such as heavy metals and reduce their availability for organisms' uptake. Most heavy metals are less soluble and less toxic In soils with high pH than in soils with low pH. Conversely, in acidic soils or in the stomach, they are generally more soluble and more toxic. Because of these effects, it is difficult to evaluate possible health effects of contaminants in soils and sediments.
3. Health Effects
Phenol is readily absorbed after inhalation, ingestion, or dermal exposure (ATSDR, 1989c). On-site groundwater consumption is not likely. Ingestion of contaminated dust could occur, but, because phenol is volatile, it is more likely to be present as a gas. Furthermore, its concentrations are higher deeper in the soil profile, in the saturated zone. The moisture at that depth would tend to inhibit dust generation during remediation. Consequently, ingestion exposure to phenol is probably negligible. After inhaling phenol, people eliminated 99 percent of the absorbed dose from their bodies within 24 hours (Piotrowski, 1971; cited in ATSDR, 1989c ). After people were given dermal applications of solutions with phenol, 80 percent of the absorbed chemical was excreted from the body within 24 hours (Baranowska-Dutkiewicz, 1981; cited in ATSDR, 1989c). The body obviously eliminates phenol efficiently.
Skin inflammation and necrosis (cell death) can occur after dermal exposure to phenol (Truppman and Ellenby, 1979; cited in ATSDR, 1989c); however, the amount needed to cause this effect in humans is unknown (ATSDR, 1989c). Remediation workers at the New Slip might contact phenol concentrations high enough to cause these effects. However, other people are unlikely to be exposed to these levels.
Inhaled phenol is a respiratory irritant in animals (ATSDR, 1989c). Remediation workers at the New Slip would be exposed to the highest airborne concentrations of phenol and would be the people most likely affected. Animals inhaling phenol have suffered cardiovascular, liver, lung, and neurological damage animals (ATSDR, 1989c), but these effects occur at higher concentrations than are likely on site.
Tests for the genotoxicity (damage to genes) of phenol in cells have been mixed (ATSDR, 1989c ). There is no evidence that phenol can cause cancer in people, and animal studies have given mixed results. Consequently, phenol cannot be classified as a carcinogen for humans (ATSDR, 1989c).
b. Polychlorinated Biphenyls
PCBs can enter the body through dermal contact, inhalation, or ingestion, but the degree of absorption for each route is unknown (ATSDR, 1987e). The primary route of exposure to PCBs for this site is the ingestion of contaminated fish. Once absorbed, PCBs tend to accumulate in fat. They can concentrate in human breast milk (USEPA, 1987a; cited in ATSDR, 1987e) and can also cross the placenta and enter the fetus (Yakushiji et al., 1978; cited in ATSDR, 1987e).
While dermal exposure to PCBs can cause chloracne, this has been observed only in occupational studies involving high concentrations and is not likely to occur in the environment (ATSDR, 1987e). However, remediation workers might contact contaminated sediments or soils with up to 420,000 ppm (42%) of PCBs. The concentration needed to cause contact dermatitis in people is uncertain (ATSDR, 1987e), but the concentration of PCBs in some on-site sediments and soils could be high enough to cause this problem.
PCBs can affect the liver by the induction of enzymes which break down foreign molecules (cytochrome P-450 and P-448; also called microsomal enzymes), and this action is not restricted to the liver (Letz, 1983; cited in ATSDR, 1987e). In addition, liver enlargement, fat deposition, and necrosis (cell death) have been seen in many species of animals exposed to PCBs (ATSDR, 1987e). When these liver effects result from exposure to low concentrations of PCBs, they are apparently reversible. Enzyme induction is the most sensitive indicator of exposure (ATSDR, 1987e). These effects are not necessarily adverse (ATSDR, 1991); however, some compounds cannot cause cancer unless they are activated by liver enzymes. Consequently, the induction of liver enzymes by PCBs could cause such compounds to convert to their carcinogenic forms (Hayes, 1987; cited in ATSDR, 1991).
PCBs can depress the immunological system of animals. A study by Thomas and Hinsdill (1978; cited by ATSDR, 1987e) suggests that the threshold for immunosuppression in monkeys is 2.5 to 5.0 ppm of PCBs in the diet. This has not been reported for people, but similar PCB levels have been found in some Lake Michigan fish, including those of Waukegan Harbor.
PCBs in the diet can decrease hormonal production by the pituitary gland of rats (ATSDR, 1987e ). Collins and Capen (1980a; cited in ATSDR, 1987e) suggested that the alteration of thyroid structure and function in dams, fetuses, or neonates could be the cause of disturbances observed in rat reproduction, growth, and development. These effects have been observed when concentrations in the rats' food were the same as those found in some fish from Waukegan Harbor and Lake Michigan. Reduced litter size occurred after rats ate food with 20 ppm or more of PCBs (Linder et al., 1974; cited in ATSDR, 1987e). In minks, 5 ppm or more in the diet reduced the birth rate and number of whelped females (Aulerich and Ringer, 1977; cited in ATSDR, 1987e). In monkeys, 2.5 and 5 ppm of PCBs in the diet for 18 months caused lengthened menstrual cycles, and, at the higher dose, reproduction was almost totally inhibited (Allen et al., 1980, 1979; Barsotti et al., 1976; cited in ATSDR, 1987e). At the lower dose, early abortions, and fetal resorptions occurred along with some live births (Allen et al., 1980, 1979; Barsotti et al., 1976; cited in ATSDR, 1987f). However, the PCBs used in this study had 1.7 ppm of polychlorinated dibenzofurans, which may have contributed to the observed results (ATSDR, 1987e). It is unknown whether PCBs used by OMC were contaminated by polychlorinated dibenzofurans. It is also unknown whether these chemicals are present in on- or off-site fish, sediments, soils, or water, with possible fish contamination being the primary concern.
Shortened gestation periods leading to lower birth weights have been observed in humans after the inhalation or ingestion of PCBs (ATSDR, 1987e). In women who regularly ate contaminated fish, newborns were an average of 190 grams lighter, had a head circumference of 0.6 cm less, and were born 4.9 days earlier than those of women who did not eat contaminated fish (Fein et al., 1984; cited in ATSDR, 1987e). However, these effects might not have been caused by PCBs, because many other contaminants were present in the fish (ATSDR, 1987e). Furthermore, Rogan et al. (1986; cited in ATSDR, 1987e) found no link between placental, maternal, or cord PCB levels at birth and birth weight or head circumference. Consequently, there is no conclusive link between maternal PCB consumption and decreased infant birth size. Jacobson et al. (1990) and Jacobson et al. (1985, 1984; cited in ATSDR, 1987e) found extremely small neurological deficiencies in the infants of mothers who consumed PCB-contaminated fish or food from contaminated farms. However, the observed effects were almost certainly too small to be observed in any one child. Furthermore, contaminants other than PCBs were present in the fish and also possibly in food from the farms. Consequently, it is uncertain whether PCBs can cause neurological effects in infants after maternal consumption.
After oral exposure, effects observed only in the stomachs of monkeys include gastritis (stomach inflammation), progressing to hypertrophy (enlargement) and hyperplasia (increase in the number of normal cells) of the gastric mucosa (stomach lining), as well as mucous-filled cysts, which penetrated the muscularis mucosa (muscle lining; ATSDR, 1987e).
Animals have developed porphyria after oral and dermal exposure; however, this effect has not been reported for humans (ATSDR, 1987e).
In one rabbit study, dermal exposure to 118 milligrams per day of PCBs 5 days per week for 38 days caused kidney damage (Vos and Beems, 1971; cited in ATSDR, 1987e). Remediation workers are the most likely people to be dermally exposed to PCBs, but it is unknown whether PCBs can damage human kidneys.
In general, tests for genotoxicity of PCBs have been negative (ATSDR, 1987e). Kimbrough et al. (1975; cited in ATSDR, 1987e) showed that PCBs can cause liver cancer (hepatocellular carcinomas) in rats. While epidemiological studies have not shown a consistent link with cancer in humans (ATSDR, 1987e), the EPA considers PCBs to be probable human carcinogens. The median fish consumption of people eating Lake Michigan fish is 34 pounds per year (Harris, 1982). People eating that amount of fish contaminated with 0.02 ppm of PCBs for 70 years would experience an estimated 1 in 10,000 cancer risk, comparable to the risk of drinking from a chlorinated public water supply. Harris reported that some people eat up to 250 pounds of Lake Michigan fish per year. People eating that amount of fish with 0.003 ppm of PCBs for 70 years would experience an estimated cancer risk of 1 in 10,000. The PCB levels in Lake Michigan fish are considerably higher than these concentrations. This means that these levels of fish consumption would lead to an unacceptably high risk. However, these risk estimates are extremely conservative. There is a 95 percent probability the actual risk is no higher and it is probably lower, maybe zero. Cancer risk estimates such as these are derived from high-dose animal studies, as these were, or occupational human studies. It is assumed that there is no threshold and there is a finite risk with any exposure. A risk estimate is made by extrapolating from the high-dose experimental data to low doses, and this approach is somewhat controversial. Some researchers believe that body repair mechanisms can handle low doses and that higher doses are needed to cause cancer. Some people also question the validity of high- to low-dose extrapolation. Until more information on carcinogenesis becomes available, USEPA takes the conservative approach that there is no threshold and that any exposure to a carcinogen carries a finite risk. In addition, these risk estimates assume that all consumed PCBs are absorbed. While this could occur for PCBs dissolved in water, it is less likely with PCBs in food and has not been measured.
Some interactions of PCBs with other chemicals have been described. Many of these interactions are related to the induction of liver enzymes by PCBs and the subsequent toxicity (lower or higher) of the compounds produced by these enzymes. Increased ascorbic acid intake could reduce some of the toxic effects of PCBs, including altered enzyme activity and liver histopathology (changes; Chakraborty et al., 1978; Kato et al., 1981; cited in ATSDR, 1987e). PCBs administered with other compounds have mixed effects on tumor development. They protected mice from lung tumors but increased the incidence of liver tumors after the administration of N-nitrosodimethylamine (Anderson et al., 1983; cited in ATSDR, 1987e). Makiura et al. (1974; cited in ATSDR, 1987e) found that ingested PCBs inhibit the carcinogenicity of 3'-methyl-4-dimethylaminoazobenzene, N-2-fluorenylacetamide, and N-nitrosodiethylamine. However, PCBs enhanced the hepatocarcinogenicity of alpha-benzene hexachloride in mice (Nagasaki et al., 1975; cited in ATSDR, 1987e) and promoted the development of enzyme-altered foci or hyperplastic (increased number of normal cells) nodules after treatment with nitrosamines or N-2-fluoremylacetamide (Tatematsu et al., 1979; cited in ATSDR, 1987e). Birnbaum et al. (1985; cited in ATSDR, 1987e) found that two particular PCBs enhanced dioxin-induced hydronephrosis (distension of the pelvis and calices of the kidney with urine because of ureter obstruction) in mouse fetuses. While one of the PCBs also caused hydronephrosis alone, the other did not (Birnbaum et al., 1985; cited in ATSDR, 1987e). Haake et al. (1987; cited in ATSDR, 1987e) found that PCBs inhibited dioxin-induced cleft palate, a birth defect, in mice. Finally, Bannister et al. (1987; cited in ATSDR, 1987e) observed that PCBs partially inhibited dioxin-induced microsomal enzyme induction and immunotoxicity in mice. These chemicals have not been found on-site, however, and any interactions between PCBs and site contaminants have not been described.
c. Polycyclic Aromatic Hydrocarbons
Many of the semivolatile organic compounds found at the New Slip-- anthracene, benz(a)anthracene, benzo(k)fluoranthene, benzo(a)pyrene, chrysene, fluoranthene, phenanthrene, and pyrene-- are polycyclic aromatic hydrocarbons (PAHs). In general, PAHs do not penetrate skin; however, they can if they are at very high concentrations (ATSDR, 1989b). Consequently, dermal exposure to PAHs in the wastes is of negligible concern, except possibly for remediation workers. PAHs can be absorbed after inhalation or ingestion (ATSDR, 1989b).
Many of the PAHs are suspected carcinogens. Benz(a)anthracene has been shown to cause skin cancer in mice, and there is evidence that it might cause cancer after oral administration (ATSDR, 1987b). In animals, benzo(a)pyrene can cause many types of tumors, including lung (inhalation exposure), skin (dermal exposure), and mammary cancer (ingestion exposure; ATSDR, 1987c). Chrysene can cause cancer in animals after dermal administration, but health effects of other routes of exposure have not yet been investigated (ATSDR, 1987d). Mixtures of PAHs, such as coal tar, can also cause cancer in animals (ATSDR, 1989e). Anthracene, fluoranthene, and pyrene cannot cause cancer in animals when administered alone (ATSDR, 1990d). The available toxicological information, however, is not sufficient to develop risk estimates for given exposures. Consequently, it is impossible to estimate the cancer risks of the site PAHs.
PAHs can have other effects on animals. After oral intake, benzo(a)pyrene can cause a decreased fertility index, a high incidence of sterility in progeny (Mackenzie and Angevine, 1981 ; cited in ATSDR, 1987c), and a significantly different pup weight, as well as increases in the numbers of stillbirths, resorptions, and malformations in mice (Legraverend et al., 1984; cited in ATSDR, 1987c).
4. State of Illinois Fish Advisories
The State of Illinois has issued fish advisories for fish from Lake Michigan based on the concentrations of many bioaccumulating chemicals, including PCBs (Tables 15 and 16). In general, bottom feeders are highly contaminated and should not be eaten. As expected, larger and older fish tend to have higher concentrations of bioaccumulating chemicals. Because chlorinated hydrocarbons, including PCBs accumulate in fat, people can minimize intake by removing the skin and fatty areas from filets (Figure 12). Although the evidence is not conclusive, cooking apparently melts some of the contaminated fat, lowering pollutant concentrations. Barbecuing, broiling, or baking fish on an elevated rack allows melted fat to drip away. Boiling and poaching also decrease the fat, providing that the broth is discarded (IEPA, 1990). These guidelines might not be sufficiently protective for people who eat average or large amounts of Lake Michigan fish. The State of Illinois is developing new guidelines that take different levels of consumption into account (Long, 1992).
No health studies could be found concerning the people in the Waukegan Area. However, an epidemiologic study of Lake Michigan fish eaters is being performed through the ATSDR Great Lakes Human Health Effects Research Program (ATSDR, 1993) and would include those in the Waukegan area.
The primary community concern is the fear of eating Lake Michigan fish, which has seriously affected the charter boat business. Eating fish from Waukegan Harbor could lead to an unacceptable cancer risk. This may also be true for the person who eats an average or large amount of Lake Michigan fish.
Another concern of the people of Waukegan is PCB contamination of their public water supply. The main water intake for the municipal water supply is about 6,000 feet offshore. Monitoring and modeling results indicate that the PCB levels in Lake Michigan are below levels of health concern. It is unclear whether the concern about water monitoring refers to groundwater, the municipal water supply, Lake Michigan, or Waukegan Harbor. Remediation workers are the only people likely to be exposed to contaminated groundwater. While remediation may increase contaminant concentrations in Waukegan Harbor, these levels should decline after cleanup.
People are also concerned that dioxins may be produced by the high temperature process proposed for removing PCBs from the most contaminated sediments and soils during remediation. The IDPH could not find any information to support or alleviate this concern.
Musgrave (1983) cited a concern about Slip 2, but the nature of this concern is unknown. Because Slip 2 was filled around 1957, it did not receive the major discharge of PCBs from OMC. However, it may have been contaminated with some of the early PCB-containing hydraulic fluids that may have spilled into the harbor before 1957. This has not been investigated. At the present, exposure of the public or on-site workers to any such buried contaminants is unlikely. On-site workers could be exposed to them in the future, but only if any contaminated sediments were excavated and brought to the surface.
Another concern is the safety of transporting PCBs extracted from the most contaminated sediments and soils. However, there are containers that can safely transport hazardous materials with a minimum risk of spillage even if there is an accident.
Some people are concerned that the proposed containment cells are inadequate for permanent disposal. While PCBs last a long time in the environment, they do not last forever. For the disposal cells to be a long-term solution, they must contain the PCBs for as long as they remain at hazardous levels.