Engelage Samantha K, Stringfellow William T, Letain Tracy
Ecology Dep., Earth Sciences Division, Lawrence Berkeley National Lab., 1 Cyclotron Rd., Mailstop 70A-3317, Berkeley, CA 94720, USA.
J Environ Qual. 2009 Jul 23;38(5):1901-8. doi: 10.2134/jeq2009.0015. Print 2009 Sep-Oct.
Trihalomethane (THM) precursors are a significant problem in the San Joaquin River (SJR) watershed, an important source of drinking water for >20 million people. Trihalomethane precursors diminish drinking water quality and are formed during natural decomposition of organic matter in aquatic systems. This study sought to identify sources of chlorine-reactive dissolved organic carbon (DOC) in the SJR watershed and to determine if wetlands were more important sources of THM precursors than nearby rivers and agricultural drains. The effects of biodegradation on DOC quality and quantity were investigated and analyzed across drainage type. Results show wetland drainage contained comparable bromide concentrations and organic carbon aromaticity but contained more than two times the average DOC concentrations found in agricultural drains and rivers. Wetland DOC did not have an increased propensity to form THMs when compared with the other drainage types, despite significantly higher wetland formation potentials. The higher formation potentials measured in wetland drainages were attributed to higher DOC concentrations; the positive correlation found between DOC and trihalomethane formation potentials (THMFPs) and the significantly higher wetland DOC concentrations suggest that increased wetland restoration could result in increased THMFPs in the SJR watershed. Wetland THM precursors were more resistant to biodegradation than THM precursors from agricultural and river samples. Results suggest that THM precursors in the SJR were from algae and were biodegraded.
三卤甲烷（THM）前体物是圣华金河（SJR）流域的一个重大问题，该流域是2000多万人的重要饮用水源。三卤甲烷前体物会降低饮用水质量，并且是在水生系统中有机物自然分解过程中形成的。本研究旨在确定SJR流域中与氯反应的溶解有机碳（DOC）的来源，并确定湿地是否比附近的河流和农业排水渠更是三卤甲烷前体物的重要来源。研究并分析了不同排水类型中生物降解对DOC质量和数量的影响。结果表明，湿地排水中的溴化物浓度和有机碳芳香性相当，但DOC平均浓度是农业排水渠和河流中DOC平均浓度的两倍多。尽管湿地的生成潜力明显更高，但与其他排水类型相比，湿地DOC形成三卤甲烷的倾向并未增加。在湿地排水中测得的较高生成潜力归因于较高的DOC浓度；DOC与三卤甲烷生成潜力（THMFPs）之间存在正相关，且湿地DOC浓度显著更高，这表明增加湿地恢复可能会导致SJR流域中THMFPs增加。湿地三卤甲烷前体物比农业和河流样品中的三卤甲烷前体物更耐生物降解。结果表明，SJR中的三卤甲烷前体物来自藻类且会被生物降解。
