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1G - Long-range transport of pollutants (chemicals) (WEP/1) Persistent Organic Pollutants (POPs) in water from italian alpine streams. Negrelli, Christian1, Villa, Sara1, Vighi, Marco1, 1 Università degli Studi Milano-Bicocca, Milan, Milan, Italy ABSTRACT- Persistent Organic Pollutants (POPs) are known to concentrate in cold environment as a result of progressive volatilisation from warm regions and condensation in colder areas. Besides Polar regions, high mountains are areas under probable stress by POPs. Mountain glaciers may accumulate atmospherically transported contaminants, acting as a temporary sink, trapping them until final ice-melt. Ice layers, deposited in 1960s and 1970s, characterized by high concentration of several POPs represent an important potential source of these contaminants to surface water. To evaluate the role of glaciers as contributors of POPs to the aquatic ecosystem, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDTs) and polychlorobiphenyls (PCBs) were measured in three glacial-fed streams from Italian alps. Samples were taken monthly during the snow free season. In each sampling valley water samples were also collected from non-glacial springs. Glacial water contamination fingerprints are dominated by HCHs, while HCB, DDTs and PCB concentrations are in most cases below detection limits. HCHs concentrations are comparable or even higher than those measured in surface water from urban and industrial areas. Seasonal trends of contamination show site-specific characteristics. According to glacier hydrology, the stream originating from a debris-covered glacier presents an unclear temporal trend: melting of contaminated layers in covered glacier do not change significantly during warm season. On the contrary, water from non-covered glacier shows higher concentrations at the end of summer, when the melting of old, highly contaminated layer is prominent. Water concentrations from non-glacial springs, 10 times lower than glacial samples, highlight the role of soil as filter of POPs and the influence of glacier melting water on the concerning HCHs concentration detected in high mountain streams. Key words: stream, POPs, glacier |
