PCBs (polychlorinated biphenyls)belong to a group of synthetic organic compounds. PCBs were widely used as lubricants, dielectric and coolant fluids in electrical apparatus. Japan banned their production in 1972, USA did so in 1979. However, PCBs in Czechoslovakia were manufactured till 1984. The factory Chemko Strážske was located in eastern part of Slovakia. During its existence, the factory produced 21,500 tonnes of these chemicals under the commercial name Delor, Hydelor or Delotherm. 46% of the production was exported, the remainder was destined for the home market. Waste water from its production was discharged into Strážske channel and Laborec river without any purification or control, leading to massive pollution of surrounding soil, surface and groundwater. PCB concentrations, even in least contaminated areas in Slovakia, are higher (sometimes very significantly) than in other countries. An estimated quarter of a million people in Slovakia were exposed to PCB.

Why are PCBs so dangerous?

PCBs represent a hazard due to its persistence and its ability to accumulate in the food chain. PCBs are non- polar (hydrophobic) substances soluble in lipids. Polychlorinated biphenyls are stored in body fat and may be excreted in the fat of breast milk. PCBs have been shown to cause cancer in animals. They also have effects on their immune system, reproductive system, nervous system and endocrine system. Studies in humans provide supportive evidence for potential carcinogenic and non-carcinogenic effects of PCBs.They are very dangerous for pregnant mothers, since they have teratogenic effects and harm the fetus. Acute toxicity of commercially used PCBs is very low. This led the producers to believe that they are almost non-toxic.

Greenpeace activists place a warning sign near Chemko’s gutter

What can be done?

Effective methods of removing such substances from our environment are chemical techniques, including combustion, photolysis and chemical degradation. These techniques can be applied only at relatively high concentrations due to its high cost. Alternative bioremediation techniques are used in cases where the contamination levels are lower but still represent risks to human and animal health. Bioremediation is a technique that involves the use of organisms to remove or neutralize pollutants from a contaminated site. These organisms, mostly bacteria and fungi, in some cases plants, break down hazardous substances into less toxic or non toxic substances.

The sad truth is that state authorithies in Slovakia are not paying the right amount of attention to this serious problem even though their citizens’ health should be top priority.