Pollution Risk and Contribution Analysis of Pb, Cd, and As in Soils and Crops Under Different Land Use Types in Longyan City

Abstract

A total of 174 soil samples and 87 grain samples were collected in two typical fields in Longyan City. The pollution index method, Hakanson potential ecological risk index method, and EPA human exposure risk assessment model were used to evaluate the pollution status, ecological risk, and health risks of heavy metals Pb, Cd, and As in soil of different land use types. The contributions of Pb, Cd, and As to soil and crop pollution risk were also analyzed. The results indicated that the pollution levels of Pb, Cd, and As in soils and crops of different utilization types in regionⅠwere low. Cd was the main soil pollutant and ecological risk factor, contributing 55.3% to comprehensive soil pollution and 60.2% to comprehensive potential ecological risk, respectively. The pollution levels of Pb, Cd, and As in soils and crops in regionⅡwere high. Pb and Cd were the main soil pollutants and ecological risk factors, contributing 44.2% and 51.6% to comprehensive pollution and 23.7% and 67.3% to comprehensive potential ecological risk, respectively. Pb was the main pollution factor of crops, contributing 60.6% and 51.7% to the comprehensive pollution of coix and rice, respectively. The carcinogenic risks of Cd and As in soil of the two typical regions for adults and children were all within the acceptable range under the oral-soil exposure pathway. The contribution of Pb, Cd, and As to the total non-carcinogenic risk in regionⅠwas Pb (68.1%)>As (30.5%)>Cd (1.38%). There was no carcinogenic risk of Pb in rice in the two typical regions under the oral-rice intake pathway. The contribution of Cd and As to carcinogenic risk in adults and children were As (76.8%)>Cd (22.7%) and Cd (69.1%)>As (30.3%), respectively. Three pollutants in regionⅠand Ⅱ had high non-carcinogenic risk, and As was the most significant contributor (84.0% and 52.0%, respectively), followed by Cd and Pb.