Arsenic speciation in environmental samples of a mining impacted sector of central Chile

Abstract

The presence of high concentrations of arsenic and copper was determined in most of the environmental matrixes under study (river water, river sediments, and soils), which suggests a real impact of the copper mining activity throughout the region, specifically the surroundings of the Caletones smelter, in the VI Region of Chile. The presence of arsenic in water and sediments is probably due to acid drainage, because pollution clearly diminished with increasing distance from the source. In the case of soils, they may be impacted by irrigation with river water. However, the high concentration values determined at sites far from the source suggest that soil pollution is more related to airborne particles deposited in soil. Arsenic speciation studies were carried out in river water samples and in edible tissues of fish (black kingclip, Chilean hake and croaker) and shellfish (clam, mussel and barnacle) samples, collected in the Pacific Ocean, close to the Cachapoal River outflow. In water samples, arsenic is mainly present as As(V); organic arsenic species (MMAA and DMAA) were not detected. In fish, around 80 % of arsenic is present as arsenobetaine.