Hazardous chemical exposure at a municipal wastewater treatment plant.

The use of municipal wastewater treatment plants for the disposal of industrial wastes creates the potential for the exposure of treatment plant workers to hazardous chemical compounds that may be present in these wastes. Urine from workers and air and wastewater samples from a municipal wastewater treatment plant receiving wastes from a pesticide manufacturer were analyzed on several occasions by electron-capture gas chromatography for the presence of the compounds hexachlorocyclopentadiene (HEX) and hexachlorobicycloheptadiene (HEX-BCH) which are present in the waste stream from this industry. HEX-BCH was detected more frequently in urine from these workers than in urine from workers at another municipal wastewater treatment plant in the same city. Urine concentrations of HEX-BCH were found to be higher in specimens collected late in the work shift than in those collected earlier. The primary rate of exposure is thought to be by inhalation. This is the first known report of these compounds being detected in human urine and it demonstrates the potential for wastewater treatment plant worker exposure to industrial wastes.