Gedrag van zware metalen en nutrienten bij natuurontwikkeling in het Beerze-Reusel Stroomgebied: een probleemverkenning

Abstract

This study represents a survey into whether mobilisation of heavy metals and nutrients can be a restrictive factor for the development of natural areas in the Beerze-Reusel basin. General risks of soil contamination for development of natural areas are first described, followed by calculations for determining risks for two specific soil types in the Beerze-Reusel basin, by means of coupling models on hydrology, acidification, heavy-metal behaviour and bioaccumulation. Considering the uncertainties in the methodology, this study has been explicitly restricted to a survey. Calculations on the risks of the combination of soil contamination (cadmium and copper), acidification (business-as-usual and an improved scenario) and (no) seepage for a meadow turned into a grassland ecosystem showed that ongoing acid atmospheric deposition in combination with soil contamination can lead to problems for the development of the grassland ecosystem. This happens both directly through acidification effects on vegetation and indirectly through effects of cadmium and copper on different species, and on biological functions of the soil. Effects on soil fauna can also lead to accumulation of organic matter, which can finally result in low species diversity. Copper generally caused less risks than cadmium, but due to ongoing increasing copper concentrations in litter and hence in soil fauna, long-term effects can occur. A scenario in which acid deposition was improved usually showed decreased risks for future ecosystems, but showed that this could also cause higher risks for a longer period due to slower leaching. A scenario comprising seepage up to 20 cm below surface showed hardly any differences in risks for development of natural areas.