Environmental Engineering and Science, Department of Chemical and Environmental Engineering (ChEE) , University of Cincinnati , Cincinnati , Ohio 45221 , United States.
Office of Research and Development, U.S. Environmental Protection Agency , Cincinnati , Ohio 45268 , United States.
Environ Sci Technol. 2018 Aug 7;52(15):8252-8262. doi: 10.1021/acs.est.8b00034. Epub 2018 Jul 9.
Microcystin-LR (MC-LR), an algal toxin (cyanotoxin) common in sources of drinking water, poses a major human health hazard due to its high toxicity. In this study, UV/chlorine was evaluated as a potentially practical and effective process for the degradation of MC-LR. Via mass spectrometry analysis, fewer chlorinated-MC-LR products were detected with UV/chlorine treatment than with chlorination, and a transformation pathway for MC-LR by UV/chlorine was proposed. Different degrees of rapid degradation of MC-LR were observed with varying pH (6-10.4), oxidant dosage (0.5-3 mg L), natural organic matter (0-7 mg L), and natural water sources. In contrast to the formation of primarily chloroform and dichloroacetic acid in deionized water where MC-LR serves as the only carbon source, additional chlorinated disinfection byproducts were produced when sand filtered natural water was used as a background matrix. The UV/chlorine treated samples also showed quantitatively less cytotoxicity in vitro in HepaRG human liver cell line tests than chlorination treated samples. Following 16 min (96 mJ cm) of UV irradiation combined with 1.5 mg L chlorine treatment, the cell viability of the samples increased from 80% after exposure to 1 mg L MC-LR to 90%, while chlorination treatment evidenced no reduction in cytotoxicity with the same reaction time.
微囊藻毒素-LR（MC-LR）是一种常见于饮用水源的藻类毒素（蓝藻毒素），由于其高毒性，对人类健康构成重大威胁。在这项研究中，紫外线/氯气被评估为降解 MC-LR 的一种潜在实用且有效的工艺。通过质谱分析，与氯化相比，紫外线/氯气处理检测到的氯化 MC-LR 产物更少，并提出了 MC-LR 经紫外线/氯气转化的途径。在不同的 pH 值（6-10.4）、氧化剂剂量（0.5-3 mg/L）、天然有机物（0-7 mg/L）和天然水源下，MC-LR 均观察到不同程度的快速降解。与 MC-LR 作为唯一碳源的去离子水中主要形成氯仿和二氯乙酸不同，当使用砂滤天然水作为背景基质时，会产生更多的氯化消毒副产物。与氯化处理的样品相比，经紫外线/氯气处理的样品在 HepaRG 人肝细胞系试验中的体外细胞毒性也定量减少。经过 16 分钟（96 mJ/cm）的紫外线照射和 1.5 mg/L 氯气处理后，暴露于 1 mg/L MC-LR 后样品的细胞活力从 80%增加到 90%，而在相同的反应时间内，氯化处理并未降低细胞毒性。
