From tailings to tables:risk assessment of potentially toxic elements in edible crops cultivated in mine tailing impacted soils

Abstract

The deposition of mine tailings in agricultural ecosystems raises concerns about the risks to human health, particularly in areas where the dissolution of mineral phases can release potentially toxic elements (PTEs). Soils and crops cultivated in the Rio Doce estuary, which has been receiving iron-rich mine tailings since 2015, were collected in August 2021 to evaluate the total concentrations of PTEs in cultivated plant species (cocoa, cassava, and bananas) in the estuary. We estimated the risks of consuming these products by calculating the Hazard Quotient (HQ), Hazard Index (HI), and Total Hazard Index (THI). Our results showed that the Cd, Cr, Cu, Ni, and Pb concentrations in all edible parts of the plants exceeded the threshold values in all the crops studied (cocoa beans, banana fruits, and cassava rhizomes). In addition, there was a possible non-carcinogenic risk associated with the consumption of banana fruits by children (THI > 1). For adults, there was no probable risk of consuming the products from the studied plants (HQ, HI, and THI < 1). In conclusion, the association between PTEs and Fe oxides, which often act to reduce PTEs' phytoavailability, was not an efficient mechanism in the studied area. This inefficiency raises concerns regarding the risk associated with food production in such environments.

Keywords: Acceptable daily intake; Human health risk assessment; Iron oxides; Metal pollution.