Distribution of dissolved and particulate heavy metals in surface water from an area affected by mining activities

Abstract

among all pollution types, the presence of metals in water and sediments, due to the pursuit of activities of mining and ore processing for long periods is experiencing a relatively high prevalence and a serious difficulty to correct. Of all the other contaminants, heavy metals detach themselves by their high toxicity, having a direct impact on ecosystems and by their capacity to accumulate both in sediments and in aquatic organisms. This paper presents the investigations carried out on sediment quality and surface water collected in 10 control sections during 2 sampling campaigns (summer, autumn), sections located in an area polluted by the mining activities (discharges of mine water, drains from sterile storage ponds). Water and sediment samples collected in the 2 campaigns were subjected to in situ analysis of physical parameters: pH, conductivity, redox potential, and in laboratory for determining the total content of metals: copper, manganese, zinc, iron, cadmium and of other pollutants (anions, organic loading) in order to establish correlations between them and to identify the forms of heavy metals presence in the environment. For metals there were determined both dissolved fraction and total metal content, when following the ratio of total metal/dissolved metal and their correlation with pH values, in order to measure the bioavailable metal fraction. Analytical test results bring meaningful contributions to the knowledge of modalities by which environment quality components close to pollution sources are affected, and of the contribution of pollutants transport in space.