Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028, China.
J Hazard Mater. 2010 Feb 15;174(1-3):40-6. doi: 10.1016/j.jhazmat.2009.09.013. Epub 2009 Sep 8.
Suspected carcinogen haloacetic acids (HAAs), as a major class of disinfection byproducts, are widespread in drinking water. Batch experiments were conducted to investigate the effect of zinc, a metal component of galvanized pipe in water distribution systems, on the fate of the HAAs. Results showed that zinc could induce sequential dehalogenation of HAAs. All brominated acetic acids were transformed to acetate ultimately, and chloroacetic acid (MCAA) was the final product for the dehalogenation of trichloroacetic acid (TCAA) and dichloroacetic acid (DCAA). The concentrations of the parent compounds as a function of time were fitted pseudo-first-order kinetic model with R(2)>0.904. Brominated acetic acids were more activated than chlorinated acetic acids in the reaction with zinc and the activity of HAAs decreased with the number of substituents reduced. While flowing through galvanized pipe, brominated and chlorinated acetic acids except MCAA would decrease to 1% of their initial concentrations in 2.11-6.34h, and the rates would not be affected obviously by the hydrodynamic or duct conditions. The health risk due to TCAA, DCAA in drinking water tends to be magnified, and that due to TBAA, DBAA tends to be first increased and then decreased, also that due to MBAA tends to be decreased.
疑似致癌的卤乙酸（HAAs）作为饮用水中消毒副产物的主要类别广泛存在。本研究通过批次实验考察了金属锌（镀锌管中金属成分）对 HAAs 归趋的影响。结果表明锌可以诱导 HAAs 的连续脱卤。所有的溴代乙酸最终都转化为乙酸，而三氯乙酸（TCAA）和二氯乙酸（DCAA）的脱卤产物则为氯乙酸（MCAA）。母体化合物浓度随时间的变化符合拟一级动力学模型，相关系数（R2）均大于 0.904。在与锌的反应中，溴代乙酸比氯代乙酸更活跃，且随着取代基数量的减少，HAAs 的活性降低。当水流经镀锌管时，除 MCAA 外，溴代和氯代乙酸在 2.11-6.34 小时内将降低至初始浓度的 1%，而流速和管道条件对其去除速率无明显影响。这可能会导致饮用水中 TCAA 和 DCAA 的健康风险被放大，而 TBAA 和 DBAA 的风险先增加后降低，MBAA 的风险则降低。
