WA9 Semi-Volatile Pollutants in Polar and Alpine Ecosystems
8:00 AM - 12:00 PM, Wednesday

() The roles of food, water and sediments in the bioaccumulation of organochlorine compounds and polycyclic aromatic hydrocarbons in high mountain lake fish.

Grimalt, Joan1, Vives, Ingrid1, Ventura, Marc2, Catalan, Jordi2, 1 IIQAB-CSIC, Barcelona, Catalonia, Spain2 CEAB-CSIC, Barcelona, Catalonia, Spain

ABSTRACT- An integrated study encompassing the distribution of organochlorine compounds (OC) and polycyclic aromatic hydrocarbons (PAH) in water, food web (chironomids, terrestrial insects, cladocerans, mollusks and cyanobacteria), sediment and fish (brown trout) from a high mountain lake (Redo, Pyrenees) is reported. OC and PAH distributions in these compartments have been determined to assess their transport routes into fish. Food diets have been estimated by analysis of fish stomach content and food web stable isotopes (d13C and d15N). OCs with Kow, higher than 106 showed lower concentrations in food than expected from theoretical octanol-water partition, indicating that the distribution of these compounds does not reach equilibrium within the life span of the food web organisms. The degree of biomagnification in fish increased with Kow,. OC exchange at fish gill. All compounds exhibited a net gill loss and a net gut uptake. A pseudo stationary state was only achieved for compounds with log(Kow) < 6. Calculation of fish average residence times for the compounds in apparent steady state gave values of days to a few weeks for HCHs, one year for HCB and 4,4'-DDE, 2-3 years for 4,4'-DDT and PCB#28 and PCB#52, and more than one decade were found for the more chlorinated PCB. Mean PAH concentrations ranged between 18 and 903 ng/g, involving Daphnia pulicaria and Siphonoperla torrentium as end-member organisms, respectively. Phenanthrene was dominant in most of the species which contrasts with the PAH composition in sediments and water column. This difference evidences a selectively accumulation of these compounds, either by differential intake and metabolization, in all lake organisms irrespectively of habitat, e.g. water column and sediments, or trophic level. PAH in S. trutta are also largely dominated by phenanthrene. PAH concentration of an estimated fish annual diet presents higher values than those in this organism.

Key words: food web, polycyclic aromatic hydrocarbons, high mountain lakes, organochlorine compounds

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