Risk Identification of Heavy Metals in Agricultural Soils from a Typically High Cd Geological Background Area in Upper Reaches of the Yangtze River.

Abstract

This study adopted two risk assessment models to estimate the potential risk of heavy metals (HMs) in agricultural soils from a high Cd geological background area. Results were as follows: HMs posed an extremely high potential ecological risk (PER) (PER = 2051 > 1200) ascribed to Cd contribution. The overall non-carcinogenic risk (HI) of HMs for children (HI > 1) was unacceptable. Contributions of HMs to HI generally decreased in the order of Cr > As > Pb > Cd > Ni > Cu > Zn. The total carcinogenic risk (TCR) value for adults (2.1 × 10-4) and children (2.2 × 10-4) surpassed the reference value (1.0 × 10-4), indicating that the risks were unacceptable. Contributions of HMs to TCR generally decreased in the order of Cr ≈ Ni > Cd > As > Pb. These results suggested that risk control policies should not only consider the potential ecological risk of Cd but also take into consideration of the carcinogenic and non-carcinogenic risk of Cr and Ni in a typically high Cd geological background area.