engleski

Contamination of some karstic area of Slovenia and Croatia with PCBs as consequence of incidents

In the last twenty years in the karstic area of Slovenia and Croatia there were two serious incidents where significant amount of PCBs inflow into the bioecological cyclus of the karst environment. The first one was in Slovenia at the beginning of seventieths because of the inadequate putting off of PCB-falls from the plant “ Iskra” for capacitors production in small town Semič, Bela Krajina, Slovenia. Discovery of PCBs contamination has come 1983, during the investigation of water of small river Krupa as potential source of drinking water for county Bela Krajina. The town Semič is around 4 km away from the source of river Krupa The plant “ Iskra” has used various PCBs oils (mostly Clophen A 50 , Clophen A30 and Pyralen 1500 from 1962. to 1985. It is estimated that about 3 to 6 tons of PCBs were emited into atmosphere, and the same range of amounts were lost during various technological manipulations. 65 to 75 tons were put off on inadequate land sites (mostly in karstic hollows) inside the plant or near vicinity. During the sanation of the contaminated area, 1986 was constructed waterproof concrete dumpsite in which was put off about 30 to 50 tons of PCBs wastes collected from karstic hollows and other sites in vicinity of the plant contaminated with PCBs. In the same time, it is estimated that between 30 and 40 tons of PCBs wastes still exist inside the karstic area of Bela Krajina county. The levels of PCBs in human blood samples collected 1984 from Semič plant workers (12 samples) and neighbourhood domestic people (11 samples) show ranges from 0.027 to 2.2 ngL-1 and 0.08 to 0.5 ngL-1 respectively. The concentration of PCBs in human adipose tissue was 9.62 .mg/kg in comparison to 0.67 .mg/kg of the non-exposed population, and 12.80 .mg/kg (on a fat basis) in poultry fat. The corresponding values in human hair and poultry plumage were 0.90 and 0.20 .mg/kg of original weight. Even though there are no large urban centers in the Croatian karst area, it deserves special attention because of its high ecological sensitivity and unfortunately unscrupulous destruction of natural resources, infrastructure, homes, and enterprises during 1991-1995. warfare. There are great fears and concrete evidence these significant quantities of polychlorinated bifenyls (PCB) ; various flame-retardants, explosives, and their by-products were released in the environment during warfare. During uncontrolled combustion of PCB and other organhalogens, even more dangerous polyhalogenated dibenzofurans and dibenzodioxins are formed, so the area under warfare operations was under even greater jeopardy-According to the collected data on warfare damage in Croatian karst area, a map has been created showing potential sources of hardly degradable harmful materials created during warfare. During 1996. waste oil and soil samples near damaged transformer stations were collected in Delnice, Zadar, Šibenik, Split, and Dubrovnik area and analyzed on polychlorinated biphenyls. Obtained results do not indicate significant contamination of soil with polychlorinated biphenyls in the transformer station or in oil taken from the oil trench TS "Delnice" and TS “ Split” . On the other side significant levels (the highest at the “ Bilice” E.T.S. over 2000 mg/kg PCBs in dry soil samples) were found in Šibenik, Zadar and Dubrovnik area.

PCB; Karst; Croatia; Slovenia; Water; Biota; Human beings

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