Distribution Characteristics and Risk Assessment of Soil Lead at a Children’s Blood Lead Exceeding Area in Fujian

Abstract

Taking Pingzhai Village in Sanming City of Fujian Provice as the researching area, the village has already outbroken Children’s blood lead exceeding and cause a lot of damage to local children. In order to reveal the reason for this serious consequence and assess the environmental risk of Pb, 24 soil samples including 12 from parent material layer and 12 from the corresponding surface layer and 4 groundwater samples are collected. The Tessier sequential extraction method is applied to analyze different speciation of Pb in soil, and Risk Assessment Code (RAC) and Ratio of Secondary Phase and Primary Phase (RSP) are both applied to evaluate Pb contamination degree and ecological risks. The results show that: the concentration of Pb in soil samples exceeds the soil Pb background values of Fujian Province, and the overall concentration of Pb shows a rising trend from the surface to parent material layer, then their accumulated pollution index range from 5.4 to 54.9 in surface layer and 4.7 to 68.1 in parent material layer. Coefficients of variation of Pb in surface and parent material layer are 79% and 86%, respectively. The lead in soil can be divided into 3 chemical speciation containing T1 (exchangeable speciation and carbonate bounded form), T2 (potential ecological risk form) and T3 (residual speciation) and Pb in soil mainly exists in T2 and T3. There shows a significant positive correlation between T2 or T3 and the total amount of Pb in soil. Pb concentration in groundwater has exceeded limited value of Standards for Drinking Water Quality. RAC and RSP ecological risk assessment results indicate that: environmental risk level of RSP is higher than it of RAC, and the contamination degree and potential environmental risk level of parent material soil are higher than them of surface soil applied by the two assessment methods.