Copper distribution and toxicity in agricultural soils of the Aconcagua fiver basin, Chile

摘要

A total of 104 topsoils were sampled at varying distances from copper mining industries in the Aconcagua river basin (north-central Chile). Salt- extractable (0.1 M KNO<,3>) and total soil copper concentrations were determined. In the areas where mining was absent, the total copper concentrations were in the range of 70-160mg/kg. Very large (above 700mg/kg, with the maximum of 3400mg/kg) and heterogeneously distributed copper concentrations were generally observed near mining activities or in areas where mining activities are located nearby upstream. On the other hand, the earthworm Eisenia fetida exhibited decreased co-coon production following eight-week exposition to the studied soils, indicating the existence of chronic toxicity. Reduction in co-coon production was better related to the total rather than to the salt-extractable concentrations of copper in the soils. About 18% of the studied soils may have potentially toxic characteristics that would limit the development of soil macrofauna.