View article

Concentrations of mercury and persistent organic pollutants in fish were examined in 11 lakes of the French Pyrénées spanning an elevation range of 2km. All lakes were confined to a relatively small area within a 50-km diameter. Most of the lakes were within the Pyrénées National Park, which is restricted to recreational hiking, angling, and seasonal grazing of livestock, and are not subject to any known point sources of contaminants. Fish collected were mainly of 1 species (Salmo trutta fario), which is stocked regularly in the lakes. With increasing elevation, lake temperatures declined along with electrical conductivity and planktonic chlorophyll a. In contrast, water column nutrients (total phosphorus and total nitrogen) and epilithic periphyton biomass were not correlated with lake elevation. Of the global contaminants measured in fish, mercury, dicholorodiphenyltrichloroethane and its derivatives, and …