Health risk assessment of heavy metal pollution in farmland downstream of Lead-zinc smelter

Abstract

In order to investigate whether heavy metals in farmland soils downstream of the abandoned lead-zinc smelter are harmful to local human health, the Plum blossom and diagonal sampling methods were used to collect the soil samples of cultivation layer (0∼25cm) from the farmland soils downstream of the abandoned lead-zinc smelter, Hui County, Gansu province, P. R. China at the end of December, 2019. The US EPA health risk assessment model was used to analyse the impact of the selected five heavy metals (Pb, As, Cr, Hg and Cd) on the physical health of local residents. The results showed that the average value of the total non-carcinogenic risk index of these five heavy metals in the soil of the three plots in the study area was 6.71 for children and 4.27 for adults, both of which were greater than 1, it meant that there were non-carcinogenic risk to both children and adults. The average cancer risk index of these five heavy metals for children was 4.49×10−4, and that for adults was 2.51×10−4, both of which are greater than 1×10−4, which is a notable cancer risk for local residents. The results provided a significant support for remediation and treatment of heavy metal contaminated farmland.