基于毒性比——效应曲线的复合污染体系联合毒性效应规律、机制及风险评价研究

Heavy metals and emerging organic pollutants are often encountered as mixtures instead of single pollutants in the environment. However, traditional environmental risk assessments are still based on single toxicity. It is therefore necessary to propose a risk assessment system for mixtures based on the joint toxicological effects of complex pollution. Heavy metals and typical emerging organic pollutants are selected as objects and their joint effects to Vibrio fischeri and Scnedesmus obliquu are determined in this study. Toxic ratios-joint effects curves are obtained by determining the joint effects of various mixtures at different toxic ratios. The variation of joint effects could then be revealed based on the toxic ratios, different components, various durations and model organisms. The joint toxic mechanism could be elucidated based on the changes of physiological characteristics and the analysis of ligand-receptor binding affinity. Combining with the determined concentrations of heavy metals and emerging pollutants in the regional environment (Anyang City), a modified factor (MF) is proposed to modify the risk assessment system of single pollutants. A novel risk assessment model for mixtures could thus be developed based on toxic ratios-joint effects curves of mixtures of multi-components at different concentrations. This study will provide insights for joint toxicity of multicomponent mixtures and their risk assessments.

环境中污染物往往以复合污染形式存在，而传统污染物风险评价体系多以单一污染物毒性数据为基础，因此研究复合污染体系的联合毒性效应规律和机制、建立复合污染物风险评价方法具有重要的现实意义。本研究选取环境中检出频率较高的重金属和新兴持久性有机污染物为目标物，以发光菌（费氏弧菌）和藻(斜生栅藻）为测试生物，通过测定不同毒性比混合物的毒性效应，得到毒性比——效应曲线，从毒性比、混合物组分变化、测试生物不同、时间依赖等方面阐释联合毒性效应变化规律；并结合生物体染毒前后生理生化特性变化及受体作用情况来揭示联合毒性的内在机制。在此基础上，根据测定得到的区域环境中（河南省安阳市钢铁工业和化工工业区）重金属和新兴有机污染物的实际复合污染状况，引入混合物风险校正系数（MF）对传统单一污染物风险评价体系进行修正，建立一个基于毒性比——效应曲线的混合物环境风险评价模型，为环境中复合污染体系风险评价提供新思路。

环境中重金属和持久性有机污染物往往会以复合污染形式存在，因此研究复合污染体系的联合毒性效应规律、建立复合污染物生态风险评价体系具有重要的现实意义。本研究以安阳市洹河流域水、土壤、沉积物为研究对象，选取环境中检出频率较高的部分重金属和典型持久性有机污染物为目标化合物，以费氏弧菌和羊角月牙藻为模式生物，研究复合污染体系的联合毒性效应规律及机制，构建了基于毒性比——效应曲线的混合物风险评价模型。.研究发现，锌、铜、铅及BDE-209、PFOA、PFOS在环境样品中均有检出，在工业区附近污染水平较高。它们的二元联合毒性的毒性比效应曲线服从正态分布，这为环境样品中混合物的联合毒性效应预测提供了基础。联合毒性机制主要表现为细胞抗氧化系统损伤，SOD酶活抑制，蛋白含量发生变化，膜通透量受到影响，进而产生联合毒性。在此基础上，以联合毒性效应（TUsum）倒数为混合物风险校正系数（MF），对传统单一污染物风险评价体系进行修正，建立了基于联合毒性效应的双级法混合物生态风险评价模型。并采用氧化石墨烯等新型纳米材料对污染物吸附去除效果进行了研究，吸附去除率达90%以上。该研究开拓了从联合毒性理论研究到实际混合物风险评价的新思路，将加深人们对环境领域复合污染物风险评价控制理论的理解和认识。