自来水厂水处理过程中碘代消毒副产物调查

Investigation of iodo-disinfection by-products in water treatment process

目的调查采用氯化消毒工艺的自来水厂水处理过程中碘乙酸与碘仿的生成变化,为健康风险评估和水处理工艺改进提供依据。方法分别于丰水期（2014年7月）、平水期（2014年10月）与枯水期（2015年2月）,采集南方某自来水厂原水、各处理环节和出厂水水样,测定碘乙酸（iodoacetic acid,IAA）和碘仿（iodoform,IF）的浓度。结果除枯水期水样未检出碘仿外,原水、各处理环节、出厂水中均可检测到碘乙酸和碘仿。原水中碘乙酸浓度为0.003～0.078μg/L,碘仿浓度为未检出～0.036μg/L;预加氯后碘乙酸和碘仿浓度升高最为明显,浓度分别为0.046～0.145μg/L和0.072～0.190μg/L;出厂水中碘乙酸浓度为0.035～0.145μg/L,碘仿浓度为0.012～0.106μg/L。水中碘乙酸和碘仿浓度具有一定季节变化规律,碘乙酸在枯水期浓度较高,而碘仿在丰水期浓度较高。结论采用氯化消毒工艺的自来水厂水处理过程中碘代消毒副产物的监测不容忽视。

Objective To investigate the occurrence of iodoacetic acid（IAA） and iodoform（IF） in water treatment process of a water plant using chlorination,and provide the basis for health risk assessment and treatment process improvement. Methods The water samples were collected from raw water in a water plant,at different treatment steps and finished water in wet season（July 2014）,normal season（October 2014） and dry season（February 2015）, and the concentration of iodoacetic acid and iodoform were determined. Results Iodoacetic acid and iodoform were detected in raw water,different treatment steps and finished water except that iodoform was not detected in raw water in dry season. In raw water,the concentration of iodoacetic acid were 0.003-0.078 μg/L,iodoform were ND-0.036 μg/L（ND：non-detected level）. After pre-chlorination,the concentration of both disinfection by-products increased dramatically. The concentration of iodoacetic acid were 0.046-0.145 μg/L,iodoform were0.072-0.190 μg/L. In the finished water,concentration of iodoacetic acid were 0.035-0.145 μg/L,iodoform were 0.012-0.106μg/L. The concentration of IAA was higher in dry season,while the concentration of IF was higher in wet season. Conclusion The iodo-disinfection by-products may be produced in the process of chlorination in water plant and more attention should be paid to the monitoring of IAA and IF in drinking water.