Toxic Metal Soil Speciation, Corn Accumulation and Health Risk Assessment in Acidic red soil Farmland in Mineral Industry Area.

Acidic red soil is a typical agrotype in southern China, how heavy metal contamination introduced by mineral industry activities, i.e. mining, smelter, and tailings may impact metal soil speciation and bioavailability in acidic red soil farmlands is not well investigated yet. In this study, soil metal concentrations, speciation, corn grain accumulation, and environmental factors affecting corn metal accumulation were analyzed. All the study sites are moderately to heavily contaminated and the contamination level decreases in the order of Cd > Pb > As > Hg > Cr. Lands near smelters have higher mobile species, extractable, exchangeable, and carbonate-bound portions account for more than 20% of the total Pb and Cd soil concentration, indicating that the two elements can be readily accumulated by plants. The hazard quotient index indicates As in soil may pose a potential non-carcinogenic health risk, while the potential risk of cancer occurrence may be induced by Cd and As through soil ingestion and dermal contact. 85% and 42% of the corn samples from the study sites exceeded the national food safety standard for Pb and Cd, respectively. The dietary intake of Cd in corn may pose a potential carcinogenic risk. The correlation analysis between the Pb and Cd accumulation in corn and the soil properties indicated that improved soil OM content may reduce the accumulation of Cd, while DTPA-extractable Pb can be used to predict the potential bioavailable Pb in soil. This work can support pollution control and aid the health risk management of mineral industry red acidic soil areas. [ABSTRACT FROM AUTHOR]