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ABSTRACT: a b s t r a c t Silver (Ag) ions are among the most toxic metallic ions to aquatic biota. In southern Argentina, fish from Patagonian lakes have liver Ag concentrations [Ag] among the highest ever reported globally. Silver con-centration in phytoplankton from Lake Moreno (1.82 ± 3.00 lg g À1 dry weight, DW) was found to be sig-nificantly higher than [Ag] in zooplankton (0.25 ± 0.13 lg g À1). Values in snails and decapods (0.60 ± 0.28 lg g À1 and 0.47 ± 0.03 lg g À1 respectively), were higher than in insect larvae (0.28 ± 0.39 lg g À1 for Trichoptera). We examined trophic transfer of Ag in the biota using stable nitrogen and carbon iso-topes ratios (d 15 N and d 13 C respectively). Silver concentrations in the biota of Lake Moreno were not asso-ciated with any particular C source, as assessed by d 13 C. Hepatic [Ag] significantly increased with trophic position, as measured by d 15 N, within the brook trout sample set. Biodilution of Ag was observed between primary producers and small forage fish when whole body [Ag] was analyzed. Nevertheless, when con-sidering whole food web biomagnification and hepatic [Ag] of top predator fish, a significant positive regression was found between [Ag] and trophic position, as measured by d 15 N. The importance of spe-cies-specific and tissue-specific considerations to obtain more information on Ag trophodynamics than that usually presented in the literature is shown. To the best of our knowledge, this is the first study in assessing Ag trophodynamics and tissue-specific biomagnification in a whole freshwater food web.
Chemosphere 02/2011; 83(83):265-270. · 3.21 Impact Factor
