engleski

Persistent toxic supstances in the Adriatic Sea and its hinterland

The Adriatic Sea is an elongated basin (139, 000 km2) of the northern Mediterranean, extending for 800 km into the heartland of the European continent. The renewal of the Adriatic water has been estimated in the range of 5 to 10 years, which is about ten times shorter than the whole Mediterranean water renewal. During the 1970s, there was increased emphasis on pollution research in the Adriatic in response to increased anthropogenic loads due to the intensive development of agriculture, industry, marine traffic, port activities and tourism in the area. An accumulation of chlorinated compound residues, contributed via the atmosphere, may have occurred in the Adriatic Sea. During 1977, airborne particulate matter was continuously sampled from the atmosphere of the residential town area of Ljubljana and trapped on a filter. The PCBs level in the particulate matter in the atmosphere was 1.3 ng/m3 and the concentration of the total DDT was -0.86 ng/m3. Polychlorinated biphenyls (PCB), organochlorine pesticides, Polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF) were measured in samples of rain and snow collected at urban and suburban/semi-rural locations in the Zagreb area, Croatia. PCB were detected in all water (<1-203 ng/L) and particles (40-4155 ng/g). The only organochlorine pesticide present in all rain and snow water (1-36 ng/L) and in particles (7-512 ng/g) was gamma-hexachlorocyclohexane due to the regular local use of lindane The Tagliamento river drains a land surface of 2, 580 km2, of which 2, 293 km2 extended on mountain, and flows into the northern Adriatic Sea. The cultured land (vineyard, orchard and arable land) represents only 29% of the watershed. The total load of chlorinated hydrocarbons delivered by Tagliamento river, estimated on the basis of their mean concentrations and a mean flow of 62 m3/s, was: 3.3 kg/yr for HCH, 1.8 kg/yr for DDT, 10.2 kg/yr for PCBs. Samples of wastewaters were collected between 1976 and 1987 at several stations located in the Rijeka Bay, Croatia. Concentrations of chlorinated insecticides and polychlorinated biphenyls in range from <0.2 to 657.2 DDTs and from <0.3 to 9115.5 ng/l for PCBs were found. The Gulf of Trieste is subject to substantial organic mercury pollution, originating from the Sofa river, that drains the cinnabar deposits of the world's second largest Hg mining area, Idrija, Slovenia( Horvat et al.1999) There are no significant difference in concentration factors for the chlorinated hydrocarbons in the open water samples. However, in more polluted coastal water samples, PCBs are more concentrated in the surface film than are DDTs and dieldrine. Comparison of natural logarithm of means and their standard error of PAH concentrations in sea water samples from the North Adriatic collected in three areas (west, middle and east) show statistically significant lower levels of polyaromathic hydrocarbons in middle part of the North Adriatic in comparison with the other two areas of the North Adriatic.

PTS; POPs; Mediterranean countries; environment

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