A field study of physiological effects on fish in lead-contaminated lakes

In a field investigation, physiological parameters were studied in whitefish (Coregonus spp.) living in lead-contaminated lakes in northern Sweden. Fish from an uncontaminated lake were used as a reference. The activity of the enzyme δ-aminolevulinic acid dehydratase in blood was inhibited up to 88% in fish from lead-contaminated lakes, as compared with fish from the reference lake, indicating the presence of lead pollution. In addition, higher blood glucose levels and lower plasma sodium content were observed in fish from lead-contaminated lakes. These results suggest that lead affects fish in the environment in a way similar to that observed in laboratory experiments.