沉积物中多环芳烃的生态风险评价法研究

评价沉积物中PAHs的生态风险对于保护整个生态系统具有重要意义,但迄今尚未建立统一的沉积物中PAHs的风险评价方法.因此,本研究以珠江广州段表层沉积物中PAHs含量为基础,综合运用相平衡分配法和物种敏感性分布法,并结合概率风险表征对沉积物中PAHs的生态风险进行评价.结果表明,沉积物中PAHs的生态风险大小主要取决于PAHs固液相分配过程.通过对不同评价结果的对比分析,总结出了一套沉积物中PAHs的生态风险评价方法.研究建议首先采用相平衡分配法将沉积相暴露浓度分布转化为孔隙水暴露浓度分布,再选择符合实际需求的水体污染物生态风险评价方法进行后续评价,其中毒性数据应优先选择慢性毒性数据.

Ecological risk assessment for polycyclic aromatic hydrocarbons in river sediments

Ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sediments is an important issue to protect the ecosystem. However, there is no generalized method for such assessment so far. Based on PAHs concentrations in surface sediment samples of the Pearl River in Guangzhou section, we applied the equilibrium partitioning method, the species sensitivity distribution method, and the probabilistic risk assessment method to characterize the ecological risk of PAHs in the river sediment. Results showed that the ecological risk of PAHs in the sediment was dominated by the solid-liquid phase partitioning process. By comparing the results of different methods, a procedure for assessing the ecological risk of PAHs in sediments was established as follows. Firstly, the distribution of PAHs in the sedimentary phase was transformed into the pore water exposure concentration distribution using the equilibrium partitioning approach. Secondly, a suitable ecological risk assessment method for water pollution was selected to meet the actual needs for following assessment. In the analysis of toxicity data, the chronic toxicity data should be used first.