Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092, Zurich, Switzerland.
Laboratory for Operation Control and Research, Zweckverband Landeswasserversorgung, 89129, Langenau, Germany.
Water Res. 2020 Sep 15;183:116066. doi: 10.1016/j.watres.2020.116066. Epub 2020 Jun 17.
Chlorothalonil, a fungicide applied for decades worldwide, has recently been banned in the European Union (EU) and Switzerland due to its carcinogenicity and the presence of potentially toxic transformation products (TPs) in groundwater. The spread and concentration range of chlorothalonil TPs in different drinking water resources was examined (73 groundwater and four surface water samples mainly from Switzerland). The chlorothalonil sulfonic acid TPs (R471811, R419492, R417888) occurred more frequently and at higher concentrations (detected in 65-100% of the samples, ≤2200 ngL) than the phenolic TPs (SYN507900, SYN548580, R611968; detected in 10-30% of the samples, ≤130 ngL). The TP R471811 was found in all samples and even in 52% of the samples above 100 ngL, the drinking water standard in Switzerland and other European countries. Therefore, the abatement of chlorothalonil TPs was investigated in laboratory and pilot-scale experiments and along the treatment train of various water works, comprising aquifer recharge, UV disinfection, ozonation, advanced oxidation processes (AOPs), activated carbon treatment, and reverse osmosis. The phenolic TPs can be abated during ozonation (second order rate constant k ∼10 Ms) and by reaction with hydroxyl radicals (OH) in AOPs (k ∼10 Ms). In contrast, the sulfonic acid TPs, which occurred in higher concentrations in drinking water resources, react only very slowly with ozone (k <0.04 Ms) and OH (k <5.0 × 10 Ms) and therefore persist in ozonation and OH-based AOPs. Activated carbon retained the very polar TP R471811 only up to a specific throughput of 25 mkg (20% breakthrough), similarly to the X-ray contrast agent diatrizoic acid. Reverse osmosis was capable of removing all chlorothalonil TPs by ≥98%.
百菌清是一种在世界范围内使用了几十年的杀菌剂，由于其致癌性和在地下水中存在潜在毒性转化产物（TPs），最近已在欧盟（EU）和瑞士被禁止使用。本研究检测了不同饮用水资源中百菌清 TPs 的分布和浓度范围（主要来自瑞士的 73 个地下水和 4 个地表水样本）。研究发现，百菌清磺酸类 TPs（R471811、R419492、R417888）比酚类 TPs（SYN507900、SYN548580、R611968）更频繁且浓度更高（在 65-100%的样本中检测到，浓度≤2200ng/L；在 10-30%的样本中检测到，浓度≤130ng/L）。在所有样本中都检测到了 TP R471811，甚至在 52%的样本中，浓度超过了瑞士和其他欧洲国家的饮用水标准 100ng/L。因此，本研究在实验室和中试规模实验中，以及在各种水厂的处理工艺中，对百菌清 TPs 的去除进行了研究，处理工艺包括含水层补给、紫外线消毒、臭氧氧化、高级氧化工艺（AOPs）、活性炭处理和反渗透。在臭氧氧化过程中，酚类 TPs 可以被去除（二级反应速率常数 k∼10Ms），并且可以与 AOPs 中的羟基自由基（OH）反应（k∼10Ms）。相比之下，在饮用水资源中浓度更高的磺酸类 TPs 与臭氧（k<0.04Ms）和 OH（k<5.0×10Ms）的反应速度非常缓慢，因此在臭氧氧化和 OH 基 AOPs 中仍然存在。活性炭对非常极性的 TP R471811 的保留能力仅达到特定的 25mkg（20%的穿透率）的通量，与 X 射线造影剂泛影酸相似。反渗透可以将所有的百菌清 TPs 去除≥98%。
