Cd, Cu and Zn concentrations in sediments and the invasive bivalves Limnoperna fortunei and Corbicula fluminea at the Rio de la Plata basin, Argentina

Cd, Cu and Zn content in sediments and bivalves ( Limnoperna fortunei and C orbicula fluminea) were studied in the lower 500 km stretch of the Parana R iver and in the right margin of the Rio de la Plata Estuary. Both bivalves species showed higher metal contents at the Parana River, possibly related to water chemistry. The Parana water is circumneutral and soft, while the R io de la Plata coastal water is alkaline, hard, with a higher organic conte nt. Bivalves sampled at the thermal effluent of the Atucha Nuclear Power Pl ant, at the Parana River, showed the highest metal content, either from inc reased absorption at the higher water temperatures (12 degrees C higher tha n the river water) or from metal corrosion of the power plant cooling syste m. L. fortunei and C. fluminea appeared to be successful biomonitor organis ms for Cd pollution in the basin, while Cu and Zn content in bivalve tissue s was apparently not related to metal load.