Mobility, bioaccumulation in plants, and risk assessment of metals in soils

Heavy metal contamination of soils is one of the main factors contributing to soil quality decline and loss of biodiversity, which is also associated with plant contamination, as metals accumulate in the surface layer of soils and then enter the trophic chain. The aims of the study were to assess the mobility and bioavailability of metals in soils to plants, and to estimate the ecological and health risks associated with heavy metal content in soils. 320 topsoil and 206 plant samples were collected. Fractional analysis showed that for most of the samples, there was no or low risk associated with the mobility of Cr, Pb, Cu, Ni, Zn, and low and medium for Cd. High and very high metal release risk was only shown for Cd (28 % of samples), and Zn and Pb (2 % of samples). The bioaccumulation factor found moderate levels of accumulation for Cd, Zn, Cu, Ni. High accumulation of Cd and Zn was found in 38 % and 15 % of plant samples. Alivibrio fischeri proved to be a more sensitive indicator of soil ecotoxicity compared to Sinapis alba. In the 81 % of the soil samples found a low probability of adverse effects on ecological receptors associated with exposure to soilborne metals. In the case of human health risk, no harmful health effects were observed due to accidental ingestion of metal-containing soils in the study area. In assessing metal risks, the choice of indicators is crucial. Moreover, the properties of soils have a significant impact on the mobility of metals and their bioaccumulation by plants. This means that the more varied the choice of indicators, the more comprehensive, reliable and close to reality the risk assessment of heavy metals in soils will be.