磺酰脲类除草剂在饮用水处理过程中的去除研究

研究了5种磺酰脲类除草剂在混凝、活性炭吸附、氯化消毒3个主要的饮用水处理单元过程中的去除情况.结果发现:只有不到10％的磺酰脲除草剂可通过混凝沉降过程去除；活性炭吸附较为有效,对这些农药的去除率可达50％～70％,但是仍不能达到完全去除；加氯消毒对磺酰脲除草剂的去除率最高,但是这一过程生成了结构稳定的产物,它们和磺酰脲分子中的杂环结构相关,可能具有毒性.总之,传统饮用水处理工艺对磺酰脲类除草剂的去除非常有限.该研究结果为全面、准确评价这类农药的生态风险以及对人体的可能暴露水平提供了依据.

Removal of Sulfonylurea Herbicides in Drinking Water Treatment Processes

Sulfonylurea herbicides are used to kill broadleaf weeds and some annual grasses. The widely application of these herbicides coupled with their resistance to photolysis, hydrolysis, and microbial degradation causes serious concern. Sulfonylurea herbicides have been detected in natural waters and could be potentially exposed to human beings via portable use. Thus, the removal of 5 representative sulfonylurea herbicides in simulated water treatment processes including coagulation, activated carbon adsorption, and chlorine disinfection was systematically investigated. Results showed that coagulation/sedimentation had little effect on the removal of the herbicides, with the average removal rates less than 10%. Powder activated carbon adsorption was apparently more effective with removal rates of 50%~70%. Nonetheless, this process could not completely eliminate the herbicides from water. Sulfonylurea herbicides were nearly completely removed during chlorination process. However, it was found that this process generated stable products which may related the heterocyclic moieties of sulfonylurea molecules. In summary, current drinking water treatment processes cannot provide enough protection for human population from exposure to sulfonylurea contamination which may be a ubiquitous problem.