以胃蛋白酶(蛋白质)、谷胱甘肽(氨基酸多肽)、葡萄糖(糖类)作为模型物质代表藻来源有机物,并以Fluka腐殖酸为对照,研究其耗氯量、三卤甲烷(主要是氯仿)、卤乙酸(主要是二氯乙酸(DCAA)、三氯乙酸(TCAA))的形成情况.结果显示4种模型物质在氯化后,其余氯在前2h迅速降低,6h后则下降速度渐缓;其中耗氯量最大的是谷胱甘肽(96h:7.1mg.mg-1(以每毫克碳计,下同)),其次是胃蛋白酶(96h:4.2mg.mg-1)、腐殖酸(96h:3.0mg.mg-1),而葡萄糖最小(96h:0.7mg.mg-1).4种模型物质氯仿、DCAA、TCAA的生成速度也是在起初的2h较快,随后渐缓;但从单位碳的产量来看,腐殖酸和胃蛋白酶形成氯仿(96h:15.1~55.2μg.mg-1(以每毫克碳计,下同))、DCAA(96h:15.1~55.2μg.mg-1)、TCAA(96h:15.1~55.2μg.mg-1)均较多,而谷胱甘肽、葡萄糖则相对较少(氯仿-96h:2.5~5.1μg.mg-1;DCAA-96h:0.6~8.0μg.mg-1;TCAA-96h:0.12~3.8μg.mg-1);而从前驱物特性来说,氯仿、TCAA的前驱物具有较高的芳香度(即高的SUV254值),而DCAA前驱物的SUV254相对较低.对于富含蛋白质、多肽、糖类等的富营养化饮用水源,则要格外注意饮用水中DCAA所带来的健康风险.
This study investigated the chlorine demand and formation of trihalomethanes(mainly chloroform) and haloacetic acids(mainly dichloroacetic acid(DCAA) and trichloroacetic acid(TCAA)) upon chlorination of several algal model compounds,including the pepsin(protein),glutathione(polypeptide) and glucose(sugar).Meanwhile,fluka humic acid was also used for comparison.Results showed that after chlorination,the residual chlorine in the solutions of four model compounds all decreased rapidly at first 2 h,and then stabilized after 6 h.The highest chlorine demand was observed in the solution of glutathione(96 h:7.1 mg·mg-1(calculated as per milligram carbon,similar hereinafter),followed by pepsin(96 h:4.2 mg·mg-1),humic acid(96 h:3.0 mg·mg-1) and glucose(96 h:0.7 mg·mg-1).THMs and HAAs formation also showed the similar transition profile characterized by quick increase at first 2 h followed by an extended slow increase.Based on unit carbon,the humic acid and pepsin showed much higher yields of chloroform(96 h:15.1~55.2 μg·mg-1(calculated as per milligram carbon,similar hereinafter)),DCAA(96 h:15.1~55.2 μg·mg-1) and TCAA(96 h:15.1~55.2 μg·mg-1) than those of gluthione and glucose(chloroform-96 h:2.5~5.1 μg·mg-1;DCAA-96 h:0.6~8.0 μg·mg-1;TCAA-96 h:0.12~3.8 μg·mg-1).However,detailed analysis suggested that the precursor of chloroform and TCAA contained more aromaticity(high SUV254 value),and the opposite was true for DCAA precursor.As for the eutrophic source water containing high level of protein,polypeptide and sugar,special attention should be paid to the health risk derived from DCAA.