Study of potential harmful elements (arsenic, mercury and selenium) in surface sediments from Serbian rivers and artificial lakes

Abstract

This investigation examines surface sediment samples from rivers and artificial lakes (Serbia) to quantify levels of potentially harmful elements (As, Hg, and Se) and several ancillary elements (Al, Fe, Mn, Ca, Mg, C, H, N, and S). These data provide the first global analysis of Hg, As and Se levels in a well-studied system. Combination of different methods was applied for estimation of the environmental status of sediments and to determine the potential risk of ecological damage: digestion with aqua regia and determination of element content, determination of elements mobile forms by ammonium-acetate extraction, calculation of contamination indexes - index of geoaccumulation and enrichment factor, comparison with sediment quality guidelines and other literature data, and use of statistical methods. Results indicate that the sediments are slightly enriched with As and Hg, but not with Se. Fact that values for Se contents was less than the international threshold levels, suggesting the very probable absence of risk of contamination over the catchment with this element. The average pollution levels in Serbian river and artificial lakes expressed in terms of geoaccumulation indexes of As and Hg indicate that the environment is uncontaminated to moderately contaminated. All values of EF for Hg were below 2, indicating deficiency to minimal enrichment with Hg on studied localities. The EF values of As indicate deficiency to moderate enrichment (EF ranged from 0.11 to 3.54). According to the comparison to quality standard, the As in sediments of the studied area have potential risk. High content of arsenic in river and lake sediments indicate that arsenic pollution problem that lasts longer period of time.