INDUSTRIAL ORGANIC-COMPOUNDS IN SELECTED CANADIAN SOILS

Studies were conducted to determine the concentrations of a large numb er of industrial organic compounds in selected Canadian agricultural s oils and to assess the potential for land application of municipal slu dges to cause significant polynuclear aromatic hydrocarbon (PAH), orga nochlorine pesticide (OC) and polychlorinated biphenyl (PCB) contamina tion of agricultural land. Twenty-four Agriculture and Agri-Food Canad a, Soil Quality Evaluation Program (SQEP) benchmark soils and six inte nsively cropped southern Ontario soils exhibited similar small concent rations of a few base-neutral and acid (BN&A) extractable industrial o rganic compounds (seldom >1 mg kg(-1) dry wt), PCBs (<200 mu g kg(-1) dry wt) and organophosphorus pesticides (OPs). Fonofos, the only OP de tected, was observed at concentrations <100 mu g kg(-1) dry wt. Neutra l and phenoxy acid herbicide analyses for 13 soils (seven SQEP and six intensively cropped) indicated infrequent detection of these compound s. There was no detection of carbamate herbicides. In most soils, only trace amounts (<10 mu g kg(-1) dry wt) of OCs were observed but in on e intensively cropped soil, DDT exceeded 70 mg kg(-1) dw. A greater in cidence of compounds such as alpha chlordane, dieldrin, aldrin and DDT in intensively cropped than in other soils is assumed to reflect incr eased use of these compounds for intensive crop production. Soils trea ted with sludge according to recommended practice exhibited minor incr eases in PAH, OC and PCB concentrations. There is no risk to human hea lth or the environment from industrial organic compounds, except possi bly DDT, in Canadian agricultural soils that have received no sludge o r from PAHs, OCs and PCBs in soils that have received southern Ontario sludges according to recommended practice.