Distribution, chemical speciation and human health risk assessment of metals in soil particle size fractions from an industrial area

Abstract

The problem associated with metal contamination in the soil is intensified in the vicinity of industrial areas as they are more susceptible to discharges from medium to small scale industries. However, limited studies are available that consider soil size fractions along with their speciation due to multi metal contamination. This information is essential to apprehend their individual and competitive mobility, bioavailability and possible de-contamination strategies. In the present study, soil samples (n = 10) were collected from Ranipet industrial area, India and analysed for total metal concentrations (Al, Cd, Cr, Cu, Fe, Mn, Pb, and Zn). The ecological risk assessment indicated substantial anthropogenic enrichment of chromium along with moderate enrichment of copper, manganese and zinc. Further, the samples were fractionized into 300–150, 150–50, 50–22 and < 22 µm; the finer fraction concentrations were used to assess human health risks. The Hazard Index (HI) values reached 2.37 for children and 0.30 in adults from non-carcinogenic risk; indicated children are at higher risk. The soil exposure risk assessment study in three different scenarios were considered; results indicated possible non-carcinogenic risk to the non-residents working in study area. The Cancer risk (CR) values followed the order CR (ingestion) > CR (dermal contact) > CR (inhalation). The speciation study performed in bulk and size fractions indicated the bioavailable forms dominated residual fractions irrespective of sizes but varied with metals. This study can be considered as a framework for risk identification and assessment from multi metal contamination in industrial area having small and shallow waterbodies.