Environmental risk assessment of metal-contaminated areas using different bioassays

Abstract

Mining activities in the areas Krompachy and Rudňany-Markušovce were focused on mining and processing of copper and mercury ore and left harmful effects on the region of Eastern Slovakia. The aim of this study is using different screening methods (XRF, Phytotoxkit and earthworm bioassays) for environmental risk assessment of metal-contaminated areas. Elemental analysis by X-ray fluorescence spectrometry indicated severe pollution of studied soils by Cu, Ni, As and Hg, which exceeded limit values. Significant positive correlation is found between Pb and Zn occurrence in the agricultural soil from Krompachy: Kluknava, and for the contents of particular metals in soil from permanent grass vegetation in Kolinovce locality, namely between Pb and Ni, Pb and Zn, and between Hg and Zn contents. A 7-day bioassay and avoidance test with the Dendrobaena veneta was used to assess the environmental risk of heavy metals in soils. The earthworms mortality was very little influenced by metals in Krompachy soils, but rather affected by Rudňany soils tailing. Phytotoxkit results for soils from Krompachy showed inhibition in germination by 32 % and 29 % for Sinapis alba and Lepidium sativum, respectively. Results of the average percentage of growth inhibition by Lepidium sativum was 28 % and 24 % for Sinapis alba. On the other hand, soil samples from Rudňany tailing showed 56 % of germination inhibition by Sinapis alba, and 49 % for Lepidium sativum, respectively. Results of the average percentage of grow the inhibition by Lepidium sativum was 48 %, and 52 % for Sinapis alba Rudňany tailing soils. The significant results (P < 0.05) of the avoidance percentages of Dendrobaena  veneta for tested soils were within the range 80 – 100 % in soils Rudňany-Markušovce tailing after 48 h. The variable toxicity of contaminated soils demonstrated the efficiency and usefulness of the Phytotoxkit and earthworm bioassays as a useful tool for evaluation of soil ecotoxicity. The results supported the expected negative impact of the soil samples on the region Eastern Slovakia.