PLANT UPTAKE OF PCBS AND OTHER ORGANIC CONTAMINANTS FROM SLUDGE-TREATED COAL REFUSE

A field study of industrial organic contaminant uptake, in particular PCB uptake, by growing crops was conducted during 1990 at the St. Davi d Coal Refuse Pile Reclamation Site, Fulton County, Illinois. The site had received one-time applications in 1987 of 785, 1570 and 3360 Mg h a-1 dry wt. of Chicago municipal sewage sludge. Corn (Zea mays L.), ca bbage (Brassica oleracea capitata L.), and carrot (Daucus carota L.) w ere grown on the sludge treatments and soil (i.e., sludge treated coal refuse) and plant samples were analyzed. Mean PCB concentrations in t he soils were less-than-or-equal-to 4 mg kg-1 dry wt. and there was no consistent effect on them of sludge application rate. Measurements on the 3360 Mg ha-1 dry wt. of sludge treatment soil indicated that seve ral organochlorine pesticides occurred at concentrations less-than-or- equal-to 217 mug kg-1 dry wt. and several polynuclear aromatic hydroca rbons occurred at <1 to 3 mg kg-1 dry wt. Mean PCB concentrations in t he plant materials were <300 mug kg-1 dry wt., however, there were dif ferences among and within crops. Concentrations decreased in the order : carrot peels > carrot tops > cabbage wrapper and inner leaves > carr ot core > corn ear leaf and stover > corn grain. There was insignifica nt PCB in corn grain. Except for cabbage wrapper leaves, the PCB conce ntrations in plant materials were not related to those in soil. Soil P CB concentrations accounted for 24% of the variance in cabbage wrapper leaf PCB concentrations and the bioconcentration factor (mg PCB kg-1 dry wt. of leaf/kg PCB ha-1 dry wt. of soil) was 0.0042. There was no detection of organochlorine pesticides in plant materials grown on the 3360 Mg ha-1 dry wt. of sludge treatment soil and, except for indole and isophorone, only trace amounts of a very few other organic contami nants were observed in the plant materials. Indole ranging from no det ection to 52 mg kg-1 dry wt. may have been a natural constituent of ca bbage. Isophorone ranging from 14 to 79 mg kg-1 dry wt. was observed i n three samples of cabbage wrapper leaves and its source is unknown. D espite the very large rates of Chicago sludge employed in this study, findings indicated that they did not (i) result in high levels of orga nic contamination in the treated coal refuse, and (ii) represent a sig nificant organic contaminant hazard to the quality for food and feedst uffs of crops grown on the treated coal refuse.