Ecotoxicology of copper and cadmium in a contaminated grassland ecosystem. I. Soil and vegetation contamination.
Emissions of cadmium and copper from a metal refinery caused widespread contamination of soil and vegetation. Dispersal followed an exponential decay away from the source area with elevated levels persisting to 3 km from the refinery. Soil profiles were characterized by surface retention of metals, which was more prominent for copper than for cadmium. The flora indigenous to the refinery was of low diversity and dominated by metal-tolerant populations of Agrostis stolonifera and Festuca rubra. Vegetation levels of copper and cadmium showed marked seasonal variation in contaminated sites, with peak values occurring in the winter months. The increased levels were from a combination of root absorption and accumulation of particulates adhered to external leaf surfaces. Sequential soil extractions and vegetation analysis implied a much greater mobility of cadmium compared with copper.