Nephrotoxic effects in free-living bank voles in a heavy metal polluted environment

Free-living bank voles (Clethrionomys glareolus) were sampled in the pollution gradient from a Swedish sulfide ore smelter and at a control site. Animals were placed in metabolic cages for 24-hours-collection of urine. Blood plasma and whole kidneys were analyzed for plasma creatinine, and metal concentrations, respectively. Urine was analyzed for volume, total protein, creatinine, and metals. Voles from the polluted site showed 30-40 times increased cadmium levels in kidney, polyuria, and increased proteinuria. Kidney concentrations of other metals than cadmium, were similar in the voles from the two locations, as were variables related to glomerular function. The proteinuria and increased urine production, appearing at 4 mg Cd kg-1in whole kidney, indicated tubular damage, the typical nephrotoxic sign of chronic exposure to cadmium.