Ecological risk assessment based on the TRIAD approach in an area contaminated by the metallurgical and mining industries

Decisions about how to remediate chemically degraded areas, including those contaminated with heavy metals, should take into account not only the restoration of soil quality but also other factors, such as an ecological risk. The aim of this work was to assess the ecological risk in an area historically contaminated with heavy metals originating from the metallurgical industry and pollution transported from outside the study area, using a multi-stage TRIAD procedure (considering different lines of evidence). This paper presents the results of chemical, ecotoxicological and ecological tests carried out on soils in the Sławków area in the Upper Silesian Industrial Region, one of the most severely polluted regions in Europe, especially contaminated with heavy metals. Conventional risk assessment methods based on determining the level of pollutants in the soil showed high content of heavy metals, especially of Cd, Pb and Zn. This level of pollution requires limiting land use and taking remedial actions. The inclusion of research based on biological methods has significantly expanded the possibilities of an assessment of the actual state of the environment. An environmental risk assessment based on the TRIAD procedure showed that the contamination has potentially fewer negative impacts on the environment and human health than demonstrated by a conventional assessment based on absolute limit values for metals.