Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
Water Res. 2022 Jun 1;216:118316. doi: 10.1016/j.watres.2022.118316. Epub 2022 Mar 17.
Warm weather and excess nutrients from agricultural runoff trigger harmful algal blooms, which can affect drinking water safety due to the presence of algal toxins and the formation of disinfection by-products (DBPs) during drinking water treatment. In this study, 66 priority, unregulated and regulated DBPs were quantified in chlorinated controlled laboratory reactions of harmful algae Microseira wollei (formerly known as Lyngbya wollei) and Phormidium using gas chromatography (GC)-mass spectrometry (MS). Live algae samples collected from algae-impacted lakes in South Carolina were chlorinated in both ultrapure water and real source waters containing natural organic matter. DBPs were also measured in finished water from a real drinking water plant impacted by a Microseira bloom. Results show that the presence of Microseira and Phormidium more than doubles total concentrations of DBPs formed by chlorination, with levels up to 586 μg/L formed in natural lake waters. Toxic nitrogen-containing DBPs also more than doubled in concentration, with levels up to 36.1, 3.6, and 37.9 μg/L for haloacetamides, halonitromethanes, and haloacetonitriles, respectively. In ultrapure water, DBPs also formed up to 314 μg/L when algae was chlorinated, demonstrating their ability to serve as direct precursors for these DBPs. When environmentally relevant levels of bromide and iodide were added to chlorination reactions, total DBPs increased 144, 51, and 24% for drinking water reservoir, Lake Marion and Lake Wateree Microseira respectively and 29% for Phormidium. Iodo-DBPs, bromochloroiodomethane, chloroiodoacetic acid, bromoiodoacetic acid, and diiodoacetic acid were observed in finished water from a drinking water plant impacted by Microseira, and bromochloroiodomethane and dibromoiodomethane were observed in chlorinated ultrapure water containing algae, bromide, and iodide. Notably, total calculated cytotoxicity tripled in Microseira-impacted waters and doubled for Phormidium-impacted waters. Calculated genotoxicity doubled for Microseira-impacted waters and more than doubled in Phormidium-impacted waters. Haloacetonitriles were major drivers of calculated cytotoxicity in algae-impacted waters, while haloacetic acids were major drivers of calculated genotoxicity in algae-impacted waters. These results provide the most extensive assessment of DBPs formed from chlorination of algae-impacted waters and highlight potential impacts to drinking water and human health. Results from this study are particularly applicable to drinking water treatment plants that employ pre-chlorination, which can cause the release of algal organic matter (AOM) precursors to form DBPs.
温暖的天气和农业径流中的过量营养物质引发有害藻类大量繁殖，由于藻类毒素的存在以及在饮用水处理过程中形成消毒副产物 (DBP)，这可能会影响饮用水安全。在这项研究中，使用气相色谱 (GC)-质谱 (MS) 定量测定了经过氯化控制的实验室反应中有害藻类 Microseira wollei（以前称为 Lyngbya wollei）和 Phormidium 中 66 种优先、不受监管和受监管的 DBP。从南卡罗来纳州受藻类影响的湖泊中采集的活藻类样本在超纯水和含有天然有机物的实际水源中进行氯化。还测量了受 Microseira 水华影响的实际饮用水厂的出厂水中的 DBP。结果表明，Microseira 和 Phormidium 的存在使氯化形成的 DBP 总量增加了一倍以上，在天然湖水中形成的 DBP 浓度高达 586μg/L。含氮有毒 DBP 的浓度也增加了一倍以上，卤乙酰胺、卤代硝基甲烷和卤乙腈的浓度分别高达 36.1、3.6 和 37.9μg/L。在超纯水中，当藻类被氯化时，DBP 也形成了高达 314μg/L，证明它们能够作为这些 DBP 的直接前体。当向氯化反应中添加环境相关水平的溴化物和碘化物时，饮用水水库、马里恩湖和沃特利湖 Microseira 的总 DBP 分别增加了 144%、51%和 24%，Phormidium 增加了 29%。在受 Microseira 影响的饮用水厂的出厂水中观察到碘代 DBP、溴氯碘甲烷、氯碘乙酸、溴碘乙酸和二碘乙酸，在含有藻类、溴化物和碘化物的氯化超纯水中观察到溴氯碘甲烷和二溴碘甲烷。值得注意的是，受 Microseira 影响的水中的总计算细胞毒性增加了两倍，受 Phormidium 影响的水中的总计算细胞毒性增加了一倍。受 Microseira 影响的水中的计算遗传毒性增加了一倍，受 Phormidium 影响的水中的计算遗传毒性增加了一倍以上。在受藻类影响的水中，卤乙腈是计算细胞毒性的主要驱动因素，而卤乙酸是计算遗传毒性的主要驱动因素。这些结果提供了对受藻类影响的水中氯化形成的 DBP 的最广泛评估，并强调了对饮用水和人类健康的潜在影响。本研究的结果特别适用于采用预氯化的饮用水处理厂，预氯化会导致藻类有机物质 (AOM) 前体的释放，从而形成 DBP。
