UNION MECHLING COMPANY
SENECA, GRUNDY COUNTY, ILLINOIS
Analytical results of samples collected during the Phase I investigation showed the presence of volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, polychlorinated biphenyls (PCBs), and metals. Groundwater samples collected during the IEPA SSI contained SVOCs, metals, suspected laboratory artifacts, and common groundwater constituents. Analytical results of the SSI soil samples showed the presence of VOCs, SVOCs, pesticides, metals, suspected laboratory artifacts, and common inorganic soil constituents. Analyses of soil and sediment samples collected during the July 1995 SIP identified the presence of contaminants similar to those found during the 1989 sampling event. The Ecology and Environment 1996 site assessment reported the presence of VOCs, SVOCs, pesticides, and elevated levels of heavy metals in the soil and lagoon sludge.
The maximum concentration of each contaminant was compared with appropriate screening comparison values, when available, to select contaminants for further evaluation for both carcinogenic and non-carcinogenic health endpoints. Chemicals that exceeded comparison values were selected for further evaluation and are shown in Tables 1 and 2.
The sampling results available and the areas of visible ground stains indicate that site surface soils are contaminated as a result of poor land management, spills of stored automotive products, the overflow of site lagoons because of rain water, and floods from the nearby Illinois River. Trespassers and past employees of the facility may have been exposed to surface contaminants by direct contact with soil, inhalation of contaminated dusts, vapors from soil volatilization, and incidental ingestion of dusts through hand to mouth activities. Concentrations of PCBs (Aroclor 1260) and lead were detected above comparison values in the lagoons, soil, and sediment. Pesticides, including DDT, DDE, and DDD, were detected above comparison values in soils in a stream that drains the west part of the facility. A list of these compounds are presented in Table 1. The USEPA's Proposed Removal Action Plan describes the proposed removal of approximately 4,500 cubic yards of contaminated soil (7). Implementation of the proposed plan should reduce the risk of any future exposures.
PCBs strongly adsorb to soil particles, have low water solubility, and are persistent in the environment (do not readily break down). PCBs can accumulate and concentrate in animals (including man) and may cause harmful effects. There is little information and much uncertainty about the human health effects caused by low level, long-term environmental exposures to PCBs. The primary organ systems or effects of concern suggested by animal and human studies of PCBs include the skin, liver, immune system, developing nervous system, reproductive system, and cancer. Based on the results of animal studies, USEPA considers PCBs to be probable human carcinogens. To date, PCBs have not been definitively linked to cancer in humans. Many occupational studies have evaluated PCB exposure and cancer and have had conflicting results (8).
Lead is most harmful to infants and children less than 7 years of age because their body systems are rapidly developing. Lead can adversely affect several major body systems if absorbed by the body, even in relatively small amounts. No safe level of ingested lead has been identified. The effects of lead are similar regardless of whether it enters the body through breathing or swallowing. Skin absorption of lead is negligible (9). The most serious effect is neurological impairment. In children, prenatal exposure, as well as potential blood levels of 10 to 15 micrograms per deciliter, have been associated with numerous disabilities, including decreased IQ, decreased growth, reduced birth weight, and reduced hearing (9). In adults, lead exposure may decrease reaction time and possibly memory and may also cause weakness in fingers, wrists, or ankles. At high levels of exposure, lead can severely damage the brain and kidneys in adults and children.
DDT, DDE, and DDD were also found in soil samples taken on site. Exposure to small amounts of those contaminants over a long time may cause reversible changes in the levels of liver enzymes. Animal studies show that long-term exposure may affect the liver while short-term exposure to these pesticides in food may have a harmful effect on reproduction. Studies in animals have shown that oral exposure to DDT can cause liver cancer; however, no such studies in humans have shown increases in deaths or cancers (10).
At this time, not enough groundwater data exist to determine if off-site groundwater contamination can be attributed to the site. Antimony and thallium are the primary groundwater contaminants of concern and were detected in the Seneca Hunt Club well above comparison values. Thallium was detected in the other three wells, but the analysis showed that part of the thallium concentration level may have been the result of laboratory contamination. In August 1991, IDPH recommended that these wells not be used for drinking and cooking purposes until enough data were available to indicate the drinking water is safe. To date IDPH has not looked at any subsequent data.
Antimony can cause diarrhea, joint and muscle pain, vomiting, anemia, and irregular heart beats. Animal studies have suggested that antimony can cause liver damage, lung cancer, and skin irritation (11).
Thallium has been associated with effects on the nervous system, lung, heart, liver, and kidney after large amounts are eaten or drunk for short periods. Also, temporary hair loss, vomiting, and diarrhea can occur. Thallium is a cumulative toxin, and for that reason, should not be consumed over long periods of time. The levels detected in the well water would not likely cause health effects if consumed for less than a year, but the water should not be used over longer periods of time. No studies were found on whether thallium can cause cancer in humans (12).
Sodium, manganese, and sulfate were detected at levels that exceeded certain secondary drinking water standards or guidelines. The high levels of sodium exceed the health guideline of 20,000 ppb for drinking water. Secondary standards are not health based, but address aesthetic issues such as color, odor, and taste.