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1 2004

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Krótki kurs historii POP. Część druga : PCB

Mastalerz P., Kluczyk A.

Wiadomości Chemiczne

2004

[Z] 58, 1-2

81--130

Polychlorinated biphenyls (PCBs) belong to the family of POPs (Persistent Organic Pollutants) which WHO (World Health Organization), EPA (Environment Protection Agency) and other prestigious institutions pronounced to be a very serious health hazard to humans and animals. It appears, however, that this pronouncement is without solid support in published scientific papers. PCBs were commercially produced since 1929 for use in electrical capacitors and transformers. It is estimated that a total of 1.5 million tons were made until the production was terminated worldwide in late 1970s. About one half of the produced amount is contained in electrical equipments which are still in use while the other half entered the environment. The presence of detectable concentrations of PCBs and their persistence in air, water and in living organisms raised concerns that human and animal health may be adversely affected. Health considerations stimulated a very intense research activity which continues unabated from 1966 with the objective of finding evidence of harmful properties of PCBs. Such evidence has not been found yet apart from some minor effects which are without serious consequences. PCBs appear to be quite harmless chemicals even when handled without proper care. This is evident from the fact that there was no single human death although several cases of poisoning by PCBs were reported. The most publicized are the accidents in Japan and Taiwan which affected about 3000 victims. However, the most serious effects were reversible dermal lesions. The most recent case of accidental poisoning occured in Belgium in 1999. The brouhaha in media was enormous although no human health effects were evident. The case of PCBs is just another example of chemophobia instigated by irresponsible enviromentalists. The three decades of PCB research resulted in enormous improvements in the analysis of trace contaminants. It is now possible to detect and quantitate each of the over one hundred PCB congeners present at concentrations in the ppb range. There are 209 PCB congeners with different numbers and positions of chlorine atoms. This article is based on a thorough search of the literature from late 1960th to the present. Unfortunately it was impossible to read all papers on PCBs in the environment because over three hundred articles are published every year. We took care, however, to learn and present the views of scientists who firmly believe that PCBs are very harmful as well as of those who do not think so. We were able to discover some very drastic examples of papers with unfounded conclusions.