Environmental contamination with polychlorinated biphenyls in the area of their former manufacture in Slovakia.

Evidently increased environmental pollution as a consequence of the 25-year manufacture of polychlorinated biphenyls (PCBs) in eastern Slovakia was observed. PCB levels determined in ambient air, soil, surface water, bottom sediment, wildlife (fish and game) samples collected in a potentially contaminated area of about 250 km2 (a part of the Michalovce district) were compared with those determined in a control area (Stropkov district). Up to 1700 ng/m3 were found in ambient air in a village close to a manufacturer's dumping site and a highly contaminated manufacturer's effluent canal whereas PCB concentrations in ambient air samples taken in villages in the control area were about 80 ng/m3 only. While soil samples taken from the agricultural fields of the polluted area contained PCBs at levels comparable with soil samples from the control area (about 0.008 mg/kg) much higher values (from 0.4 to 53,000 mg/kg) were determined in soil taken in the vicinity of manufacturer's landfill and storage sites and especially plants preparing asphalted gravel using formerly PCBs in their heat-exchanging systems. The contamination of the Laborec river and large Zemplinska Sirava reservoir is caused by the manufacturer's effluent canal since PCB levels in the canal sediment are still to be found about 3000 mg/kg. While PCB levels in sediment samples from Michalovce watercourses ranged between 1.7 and 6 mg/kg, sediment samples from the control Stropkov district ranged between 0.007 and 0.052 mg/kg only. Fish living in contaminated Michalovce waters contained about hundred times higher PCB levels than those caught in Stropkov ones. Similarly, game animals shot in Michalovce forests contained several times higher levels than those shot in Stropkov ones.