Health Risk Assessment on PAHs Contaminated Site-A Case Study in a Relocated Coke and Chemical Plant in Beijing

摘要

Taken polycyclic aromatic hydrocarbons (PAHs) in a relocated coke and chemical plant in Beijing for example, the procedures of contaminated site health risk assessment adopted in China were introduced, and potential risk control and mitigation alternatives were proposed. The hazard indentification results revealed that the surface soil was heavily polluted by fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b,k]fluoranthene, benzo[a]pyrene, indeno[l,2,3-cd]pyrene, dibenz[a,h]anthracene, and benzo[g,h,i]perylene throughout the site, and their maximum concentrations were all beyond the corresponding screening levels. But based on the exact exposure characteristics of the receptors in each sub-area, the risk assessment results indicated that only the cancer risk from benz[a]anthracene, benzo[b,k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and dibenz[a,h] anthracene were unacceptable, among which the cancer risk from benzo[a]pyrene was the highest, up to 4.4×10~(-5) in zone A, 2.0×10~(-4) in zone B and 4.0×10~(-4) in zone C, which were proposed to be redeveloped as commercial zone, industrial site park, and comprehensive development zone, respectively. In addition, for all contaminants in the three sub-areas, oral ingestion and dermal contact were the two most important exposure pathways. According to the results, an active remediation alternative aiming at decontaminating the polluted soil, a soft strategy aiming at cutting off the exposure pathways and a strategy aiming at changing the exposure characteristic of the receptors through land function change were proposed as the management strategy for the site to mitigate and control the health risk.