Assessing toxicity of metal contaminated soil from glassworks sites with a battery of biotests

Abstract

The present study addresses toxicological properties ofmetal contaminated soils, using glassworks sites in southeastern Sweden as study objects. Soil from five selected glassworks sites as well as from nearby reference areas were analysed for total and water-soluble metal concentrations and general geochemical parameters. A battery of biotestswas then applied to assess the toxicity of the glassworks soil environments: a test of phytotoxicitywith garden cress (Lepidium sativum); the BioTox™ test for toxicity to bacteria using Vibrio fischeri; and analyses of abundancies and biomass of nematodes and enchytraeids. The glassworks- and reference areaswere comparable with respect to pH and the content of organic matter and nutrients (C, N, P), but total metal concentrations (Pb, As, Ba, Cd and Zn) were significantly higher at the former sites. Higher metal concentrations in the watersoluble fractionwere also observed, even though these concentrationswere lowcompared to the total ones.Nevertheless, toxicity of the glassworks soilswas not detected by the two ex situ tests; inhibition of light emission by V. fischeri could not be seen, nor was an effect seen on the growth of L. sativum. A decrease in enchytraeid and nematode abundance and biomass was, however, observed for the landfill soils as compared to reference soils, implying in situ toxicity to soil-inhabiting organisms. The confirmation of in situ bioavailability and negative effects motivates additional studies of the risk posed to humans of the glassworks villages.