滩涂养殖生境中除草剂类内分泌干扰物迁移转化及选择性去除机制研究

Herbicides are usually applied to prevent weeds and remove harmful algae in agriculture and fishery. The serious influence of these compounds on the aquaculture and breeding usually occurs at low residue level because of the endocrine-disrupting property of these herbicides. Therefore, determining the pollution condition and removal of herbicides with endocrine-disrupting properties in a tidal flat habitat is important to protect the tidal flat ecology and eliminate the hazards of aquaculture and breeding. In this study, the pollution condition, migration, and transformation of these herbicides were first elucidated by simulating a natural tidal flat ecology. Furthermore, novel molecularly imprinted nanostructured magnetic microspheres were fabricated by surface grafting technique and used as carrier of herbicide-degrading bacteria which can improve the efficiency of degrading a specific trace herbicide. Finally, the degradation efficiency was investigated according to the migration and transformation characteristics of herbicides with endocrine-disrupting properties influenced by the immobilized bacteria in the fabricated magnetic microspheres. The results obtained in this study could provide the theoretical and technological support to eliminate the hazards of herbicides with endocrine-disrupting compounds in tidal flat aquaculture and aquatic products.

除草剂是现代农业及渔业生产中防治杂草、清除有害藻类的重要手段，由于其部分种类具有内分泌干扰特性，在较低的浓度下对水产养殖、育苗也可造成严重影响。因此，开展滩涂养殖生境中除草剂类内分泌干扰物污染状况和去除机制研究，对保护滩涂生态系统，消除对水产养殖、育苗等的危害具有重要意义。项目组拟通过模拟自然滩涂养殖生境，解析除草剂类内分泌干扰物及其降解中间产物在滩涂养殖生境中的污染特征、迁移转化规律。在此基础上，采用表面接枝技术，获得针对滩涂养殖生境中除草剂类内分泌干扰物的新型分子印迹纳米结构磁性微球，并将其作为载体固定除草剂降解菌，特异性的提高微量除草剂类内分泌干扰物的去除效率，同步解析分子印迹纳米结构磁性微球固定降解菌介导的除草剂类内分泌干扰物迁移、转化规律，阐明滩涂养殖生境中微量除草剂类内分泌干扰物的选择性去除机制，为消除除草剂类内分泌干扰物对滩涂养殖、育苗带来的危害提供理论依据和技术支持。

除草剂是现代农业及渔业生产中防治杂草、清除有害藻类的重要手段，由于其部分种类具有内分泌干扰特性，其残留对水产养殖、育苗和水产品安全造成严重影响。本项目通过建立、完善海水、沉积物、水产生物样品中60种除草剂的高通量检测方法，建立了象山港、杭州湾等滩涂近海环境中除草剂残留背景数据库，并阐明其在环境及生物样品中的污染特征、时空分布特征及影响因素。进一步通过模拟滩涂养殖环境，重点解析了除草剂类内分泌干扰物莠去津及其降解中间产物的污染特征、迁移转化规律，阐明了莠去津及其降解产物的积累状况及迁移转化机制。同时，为有效去除除草剂残留污染，采用表面接枝技术，获得对莠去津等具有特异吸附能力的分子印迹纳米结构磁性微球（MIP-Fe3O4-QDs）等，采用透射电镜、红外光谱、选择性分析等解析其表面特征、吸附特性，构建了可特异吸附莠去津等特征除草剂的选择性吸附体系。在此基础上，用海藻酸钠将MIP-Fe3O4-QDs与降解菌进行包埋，构建MIP-Fe3O4-QDs固定化菌，通过优化固定化菌最佳降解条件，并通过解析不同降解条件下固定化菌降解体系的降解特性，阐明了滩涂养殖生境中莠去津等特征除草剂的选择性去除机制。相关研究结果可为有效控制和去除除草剂类内分泌干扰物残留对滩涂养殖、育苗带来的威胁提供理论依据和技术支持。