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Cd and Pb concentrations in the liver, kidney, and stomach contents of Arctic char (Salvelinus alpinus) from an oligotrophic high mountain lake (Schwarzsee ob Solden Tyrol, Austria) with low pH (4.8 to 6.4) and alkalinity (-8 to +8 μequiv.·L -1 ) were investigated over the course of 1 year. Peak concentrations of Cd and Pb in the water coincided with the drop of pH during snowmelt, whereas metal concentrations in liver and kidney were lowest at the end of winter and increased during summer. Furthermore, the Cd and Pb load of the food was considerably higher in winter than during summer. Thus, fluctuations in the metal levels in fish did not correlate with seasonal variations in the metal concentrations in lake water or in the diet. Rather, patterns of metal accumulation in the fish indicated that enhanced metal uptake was a consequence of increasing metabolic rates during summer. Thus, water temperature appeared to be the driving force of metal accumulation in fish from an oligotrophic lake. Concentrations of Cd and Pb in liver and kidney were positively correlated to age. A simple empirical model illustrates the ability of the fish to eliminate considerable amounts of accumulated metals. Resume : On a etudie pendant 1 an les concentrations de Cd et de Pb dans le foie, les reins et le contenu de l'estomac d'ombles chevaliers (Salvelinus alpinus) provenant d'un lac oligotrophe de montagne situe en altitude (Schwarzsee ob Solden Tyrol, Autriche), dont l'eau presentait un faible pH (4,8 a 6,4) et une faible alcalinite (-8 a +8 μequiv.·L -1 . Les concentrations maximales de Cd et de Pb dans l'eau coincidaient avec la chute du pH pendant la fonte nivale, tandis que les concentrations d'especes metalliques dans le foie et les reins etaient au minimum a la fin de l'hiver et augmentaient durant l'ete. De plus, la charge de Cd et de Pb dans les aliments etait considerablement plus elevee a l'hiver qu'a l'ete. Il n'y avait pas de correlation entre ces fluctuations de concentrations d'especes metalliques dans les poissons et les variations saisonnieres des concentrations de metaux dans l'eau du lac ou dans la nourriture. Les modes d'accumulation de metaux dans le poisson indiquaient plutot que c'etait l'accroissement des taux metaboliques durant l'ete qui etait a l'origine de l'absorption accrue de metaux. La temperature de l'eau serait donc responsable, semble-t-il, de l'accumulation d'especes metalliques dans les poissons des lacs oligotrophes. Il y avait une correlation positive entre l'âge et les concentrations de Cd et de Pb dans le foie et les reins. Un simple modele empirique permet de montrer que les poissons peuvent eliminer des quantites considerables de metaux accumules. (Traduit par la Redaction)

We studied Arctic char (Salvelinus alpinus) from five oligotrophic Alpine lakes in northern Tyrol, Austria, that differed in altitude (929–2796 m above sea level), pH (pH 5.4–8.3), and alkalinity (1.3–2750 μequiv.∙L−1). Concentrations of Cd, Pb, Zn, and Cu were measured in the water and in the kidney of fish, allowing the calculation of metal bioconcentration factors between water and fish kidney. Despite relatively low Cd and Pb concentrations in the water (Cd, 0.1 μg∙L−1; Pb, 0.5 μg∙L−1, dissolved), metal concentrations in the kidneys of fish from the most acidic lake (Cd, 123 μg∙g−1; Pb, 19 μg∙g−1, dry weight) were comparable with those of fish from waters polluted by direct discharge of metals. Concentrations of Cd and Pb in the kidney were negatively correlated with the alkalinity of the lakes. Comparison with data from other studies confirms the predictive utility of water alkalinity for estimating Cd accumulation in fish from oligotrophic lakes. The correlation between bioconcentration factors and alkalinity was negative for Cd and Pb, positive for Zn, and nonsignificant for Cu.