Effects of climate change on the toxicity of soils polluted by metal mine wastes to Enchytraeus crypticus.

The present study aimed to assess the effects of climate change on the toxicity of metal-polluted soils. Bioassays with Enchytraeus crypticus were performed in soils polluted by mine wastes (mine tailing, forest, and watercourse) and under different combinations of temperature (20 °C and 25 °C) and soil moisture content (50% and 30% of the soil water-holding capacity). Survival and reproduction were set as endpoints. No effect was observed on survival (average survival ≥ 80%). Reproduction was the most sensitive endpoint, and it was reduced between 65% and 98% compared with control after exposure to watercourse soil (lower pH, higher salinity, and higher available metal(loid) concentrations). In this soil, effective concentrations at 50% and 10% (EC50 and EC10) significantly decreased with decreasing soil moisture content. In general, the worst-case scenario was found in the driest soil, but the toxicity under a climate change scenario differed among soil types in relation to soil properties (e.g., pH, salinity) and available metal(loid) concentrations.