SWIFT AGRICULTURAL CHEMICALS FAIRMONT CITY PLANT
FAIRMONT CITY, ST. CLAIR COUNTY, ILLINOIS
The primary focus for this discussion is possible exposure to contaminated sediments present off site and the possible health effects related to exposure. The analytical results are listed in the tables, and the comparison values for each contaminant are also presented. Table 2 contains the on-site soil and sediment sampling results. Table 3 contains a list of contaminants, which exceeded comparison value levels, in off-site sediment samples. The contaminants present in groundwater at levels exceeding comparison values are presented in Table 4.
Comparison values are contaminant concentrations in specific, environmental media used to select contaminants for further evaluation. The values include Environmental Media Evaluation Guides (EMEGs) for chronic exposures (CEMEGs) and intermediate exposures (IEMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. CREGs are estimated contaminant concentrations are derived from USEPA's cancer slope factors and represent a level at which one excess cancer may occur in one million people exposed to that level. See Attachment 2 for a detailed description of the comparison values used.
The compounds expected to be related to a fertilizer manufacturing plant would primarily be nitrogen compounds, acids (sulfuric and phosphoric), and pesticides mixed with the fertilizer. PAHs, most pesticides, and other inorganic compounds would not be associated with the site. Inorganic compounds and PAHs, from the producer gas plant, have been associated with the neighboring Old American Zinc site.
The groundwater beneath the site was slightly contaminated with Heptachlor and inorganic compounds. Workers and residents are not likely exposed to the contaminants in groundwater because residential drinking water is provided by a municipal system. Groundwater samples were not tested for nitrates and nitrites; however, because the community is on a municipal system, that information is not needed to evaluate the public health impact of groundwater on people in the area. The nearest community wells are approximately 2 1/2 miles northeast and upgradient of the site. The nearest known residential well is approximately 1/2 mile north of the site. This residential well is upgradient of the site. IDPH collected a sample from this well and analyzed it for inorganic compounds. No inorganic compounds, including nitrates and nitrites, were found.
Table 2 lists the compounds found in the on-site soil and sediment samples. The soil comparison values are presented for a pica child (one who demonstrates excessive hand to mouth activity), a non-pica child, and an adult when appropriate and available. On-site soil and sediment samples contained PAHs, pesticides, and inorganic compounds. Benzo(a)pyrene (BaP) was higher in off-site sediments than it was on-site. That fact suggests that BaP is not site related. The pesticides found at levels greater than comparison values are heptachlor, heptachlor epoxide, aldrin, and dieldrin. We do not know if those compounds were ever used on the site.
The site is fenced, so people are not likely to be chronically exposed to soils on the site. Both past and present on-site workers are the only people who are likely to come in contact with contaminants present in surface soil and sediment. Exposure to the levels of contaminants found in on-site soils is not expected to cause health effects in those workers. Off site, people may come in contact with contaminated sediments. (See Table 6.)
Sediment samples S10 and S11 were taken from culverts along Kingshighway, and samples S7 and S8 were taken along the southwestern corner of the Old American Zinc site. Sample S3 was taken from a drainage ditch northwest of the site, and S9 was taken from a drainage ditch at the southeast corner of the site. BaP was detected at levels greater than comparison values in four of six off-site sediment samples. Heptachlor was detected in 2 samples, one of which was greater than the comparison value. Dieldrin was detected in all six sediment samples at levels greater than comparison values. The sediment sample taken upstream of the site contained the highest level of dieldrin.
Antimony was detected in only one sediment sample, S10, which is upgradient from the site. Arsenic concentrations were above the comparison value for children in samples S7, S8, and S10. Beryllium, cadmium, manganese, thallium, and zinc were highest in the four samples taken along the southern site boundary of Old American Zinc. The zinc smelter site appears to be the source of those metals. Lead concentrations were greater than 1,000 ppm in samples S7, S8, S10, and S11. The sources of lead in the sediments may be related to the Old American Zinc site and the highway.
Contact with surface water or airborne contaminants is not likely to occur on or off the site. The only potential for airborne exposure would be from wind blown dust; however, the levels of contaminants on the site are not high enough to significantly contaminate the air. Surface water running off the site is not known to flow to a permanent body of water. Children may contact contaminated sediments in off-site areas. Contact with these sediments probably only occurs sporadically and the primary contaminants of concern are inorganic compounds, probably from the zinc smelter.
Childhood Health Initiative
IDPH and ATSDR recognize the sensitivity of children to some of the contaminants found at the site. Therefore, IDPH included estimated doses for children when evaluating site conditions. Estimated doses for children exposed to off-site sediments were calculated for both cancer and noncancer endpoints. Exposure calculations for each contaminant present at levels above comparison values are presented in Attachment 3. Because off-site sediments were not tested for aldrin and heptachlor epoxide, the highest concentrations of those compounds on the site were used to estimate the exposure dose. All estimated doses were calculated using the highest concentration found in off-site sediment. The calculation assumptions are that exposed children weigh 16 kilograms (kg), ingest 100 milligrams of soil per day (mg/day), and contact the sediments two days per week, 6 months per year, for 10 years.
A summary of the estimated doses and a comparison of the doses with their respective noncancer health guidelines is presented in Table 5. No estimated doses for exposure to sediments exceeded chronic noncancer minimum risk levels (MRLs); therefore, children, as described in our assumptions, who contact contaminated sediments are not expected to experience adverse health effects. Additionally, children are not expected to experience an increased risk of developing cancer as a result of exposure to contaminants in off-site sediments.