Development of an ecotoxicological assessment concept for contaminants based on their bioavailability in soils with different filter und buffer properties

Development of an ecotoxicological assessment concept for contaminants based on their bioavailability in soils with different filter und buffer properties

The German Federal Soil Protection Act defines precautionary values for seven metals/metalloids which, if exceeded, indicate that concern for a harmful soil change exists, taking geogenic or wide-spread, settlement-related pollutant concentrations into account. All precautionary values given in the German Soil Protection Ordinance are based on total concentrations (aqua regia extraction). However, total metal/metalloid concentrations do not represent the actual exposure of soil organisms to these metals/metalloids. A realistic ecotoxicological assessment concept for contaminants should consider their bioavailability in soil, e.g. by taking soil properties such as texture, pH, or organic matter content into account. In order to cover the normal variability of natural soils, six soils were selected that are representative for Central European conditions. The aim of this project is to relate bioavailable fractions of arsenic to ecotoxicological effect concentrations. The former are determined by several chemical extraction methods, and the latter by standard laboratory tests following OECD and ISO guidelines with microbes, plants, earthworms and springtails. Arsenic was chosen, because its ecotoxicological effects in soil are not well-known.