[Distribution Characteristics,Sources Analysis,and Potential Ecological Risk Assessment of Heavy Metals in Soils of Typical Hazardous Waste Incineration Disposal Sites].

Abstract

To explore the heavy metal pollution characteristics and ecological risk status of soil in typical hazardous waste incineration disposal sites, data was collected from 85 different depth profiles of soil samples taken from five typical hazardous waste incineration disposal sites in Shanghai. The pollution level and potential risk of six heavy metals （Hg, Cd, As, Pb, Ni, and Cu） were evaluated using the geo-accumulation index, the Nemerow comprehensive pollution index, and the potential ecological risk index, and the APCS-MLR receptor model used to analyze the pollution sources. The results showed that： ① Varying degrees of accumulation of the six heavy metals exist in the soil of the study area. Except for As, the content of other heavy metals in the surface soil exceeded the background value, and the degree of pollution decreased with increasing soil depth. The proportion of moderately accumulated sites for Cu and Cd was relatively high, and there were certain heavily polluted sites in the surface soil, which posed a high local risk. ② The results of the APCS-MLR receptor model indicated that source 1 （Cu, Pb, and Cd） was mainly affected by stockpiling and transportation, source 2 （As） was mainly affected by natural geological background, source 3 （Hg） was mainly affected by the hazardous waste incineration process, and the other source （Ni） was mainly affected by mixed sources in multiple ways. ③ The geo-accumulation index indicated that there was no pollution of the six heavy metals at different vertical depths in the study area. The Nemerow comprehensive pollution index showed that 5.88% of the surface soil samples in the study area were moderately polluted, 2.94% were severely polluted, and the remaining points were at a mild pollution level. The potential ecological risk index showed that the entire study area was at a mild pollution level, with some locations presenting strong risks. Severe local pollution may exist in concentrated areas, and the main potential risk factors were Hg and Cd.