基于贝叶斯方法的太湖沉积物多环芳烃的生态风险评价  

A Bayesian approach for ecological risk assessment of polycyclic aromatic hydrocarbons in sediments of Taihu Lake

作　　者：倪玲玲 王栋 王远坤 陶雨薇 王艳磊 Ni Lingling Wang Dong Wang Yuankun Tao Yuwei Wang Yanlei(Department of Hydrosciences, School of Earth Science and Engineering, Nanjing University, Nanjing, 210023, China)

机构地区：[1]南京大学地球科学与工程学院水科学系,南京210023

出　　处：《南京大学学报（自然科学版）》2017年第5期871-878,共8页Journal of Nanjing University（Natural Science）

基　　金：江苏省太湖水环境综合治理科研项目(TH2014307)

摘　　要：多环芳烃是一类具有高毒性的持久性有机污染物,沉积物是多环芳烃的主要环境归宿.在化学物质的概率生态风险评价中多应用经典频率理论,但在小样本情况下用频率代表概率进行统计推断,其精度和可信度值得商榷.为提高小样本情况下生态风险评价中参数估计的准确性及可靠性,以贝叶斯方法为基础构建模型以估计暴露分布及效应各参数,并定义了暴露分布与效应分布的联合概率为生态风险,利用参数估计产生的模拟样本结合蒙特卡罗方法估算了风险,以提高统计推断效果.将此方法应用于太湖沉积物多环芳烃的联合生态风险评价中,研究结果揭示,其生态风险在可信水平为90%的可信区间为0.24%~9.69%.风险评价的不确定性分析及敏感性分析结果表明,效应分布参数是风险估计的主要不确定性来源.Ecological risk assessment of polycyclic aromatic hydrocarbons（PAHs）in sediments is an important issue to protect the ecosystems.The Classical statistics were often used in the probabilistic risk assessment.However,the samples are too small to obtain a credible and reliable statistical conclusion in the environmental field.To increase the accuracy and reliability of estimating distribution parameters in ecological risk assessment,this paper used Bayesian models based on Bayesian approaches to derive exposure concentration distributions（ECD）and species sensitivity distributions（SSD）,defining the probability corresponding to the area under the curve of ECD and SSD as the expected potentially affected fraction（EPAF）which described the joint probability of ecological risk.Monte Carlo method was used to calculate the probability of ecological risk by taking advantage of the samples generated from Markov Chain Monte Carlo simulation.Employing these methods in the ecological risk assessment of PAHs existing in sediments of Taihu Lake,the estimated EPAF values suggested that 90% credible interval of ecological risk was 0.24%~9.69%.Besides that,the uncertainty analysis and parameters＇ sensitivity analysis indicated that parameters which derivedfrom ecological response analysis were the main source of uncertainty in the procedure of risk estimates.

关 键 词：贝叶斯方法 生态风险评价 多环芳烃 沉积物 太湖 

分 类 号：TP181[自动化与计算机技术—控制理论与控制工程]