Marabini Laura, Frigerio Silvia, Chiesara Enzo, Radice Sonia
Department of Pharmacology, Chemotherapy and Medical Toxicology "E. Trabucchi", University of Milan, Via Vanvitelli, 32, 20129 Milan, Italy. laura.marabiniunimi.it
Water Res. 2006 Jan;40(2):267-72. doi: 10.1016/j.watres.2005.10.038. Epub 2005 Dec 19.
It is well known that water disinfection through chlorination causes the formation of a mixture of disinfection by-products (DBPs), many of which are genotoxic and carcinogenic. To demonstrate the formation of such compounds, a pilot water plant supplied with water from Lake Trasimeno was set up at the waterworks of Castiglione del Lago (PG, Italy). The disinfectants, continuously added to pre-filtered lake water flowing into three different basins, were sodium hypochlorite, chlorine dioxide and peracetic acid, an alternative disinfectant used until now for disinfecting waste waters, but not yet studied for a possible use in drinking water treatment. The aim of this study was to evaluate the formation during the disinfection processes of some toxic compounds that could explain the genotoxic effects of drinking waters. Differently treated waters were concentrated by solid-phase adsorption on silica C(18) columns and toxicity was assessed in a line of human hepatoma cells (HepG2), a metabolically competent cellular line very useful for human risk evaluation. The seasonal variability of the physical-chemical water characteristics (AOX, UV 254 nm, potential formation of THM, pH and temperature) made indispensable experimentation with water samples taken during the various seasons. Autumn waters cause greater toxicity compared to those of other seasons, in particular dilution of the concentrate at 0.5l equivalent of disinfected waters with chlorine dioxide and peracetic acid causes a 55% reduction in cellular vitality while the cellular vitality is over 80% with the all other water concentrates. Moreover it is very interesting underline that non-cytotoxic quantities of the autumnal water concentrates cause, after 2h treatment, a decrease in GSH and a statistically significant increase in oxygen radicals, while after prolonged treatment (24h) cause a GSH increase, without variations in the oxygen radical content. This phenomenon could be interpreted as the cellular adaptation response to an initial oxidative stress.
众所周知，通过氯化进行水消毒会导致形成消毒副产物（DBPs）混合物，其中许多具有遗传毒性和致癌性。为了证明此类化合物的形成，在意大利卡斯蒂廖内德尔拉戈（PG）的自来水厂建立了一个以特拉西梅诺湖湖水为水源的中试水厂。消毒剂持续添加到流入三个不同水池的预过滤湖水中，消毒剂分别是次氯酸钠、二氧化氯和过氧乙酸，过氧乙酸是一种替代消毒剂，此前一直用于废水消毒，但尚未研究其在饮用水处理中的潜在用途。本研究的目的是评估消毒过程中一些有毒化合物的形成情况，这些化合物可能解释饮用水的遗传毒性作用。不同处理的水通过在硅胶C(18)柱上进行固相吸附进行浓缩，并在人肝癌细胞系（HepG2）中评估毒性，HepG2是一种代谢功能健全的细胞系，对人类风险评估非常有用。水的物理化学特性（可吸附有机卤化物、254nm紫外线吸光度、三卤甲烷的潜在形成量、pH值和温度）的季节变化使得必须对不同季节采集的水样进行实验。秋季的水比其他季节的水毒性更大，特别是用二氧化氯和过氧乙酸将浓缩液稀释至相当于0.5升消毒水时，细胞活力降低55%，而其他所有水浓缩液的细胞活力超过80%。此外，非常有趣的是要强调，秋季水浓缩液的非细胞毒性量在处理2小时后会导致谷胱甘肽减少，氧自由基有统计学意义的增加，而在长时间处理（24小时）后会导致谷胱甘肽增加，氧自由基含量没有变化。这种现象可以解释为细胞对初始氧化应激的适应性反应。
