ABSTRACT

Recycling residual sludge in drinking water treatment plants (DWTPs) may release excessive heavy metals and organic matter, which are substances of concern because of their toxic and carcinogenic potential. The aim of this study was to investigate potential genotoxic, cytotoxic, and mutagenic effects of recycled residual sludge in terms of quality of water in potable water works. Genotoxic effects of reusing residual sludge were evaluated using: the Ames test, sperm abnormality test in mice, micronucleus assay, comet assay, and single-cell gel electrophoresis assay. The results of the Ames assay show that the disinfected water sample displays bacteriostasis at a dose of 7 L/dish regardless of treatment styles, but mutagenicity ratio (MR) < 2 can still be judged as negative. The micronucleus rates of conventional treatment were slightly genotoxic but only at 4 and 40 L/kg·bw, whereas micronucleus rates of filtered water and disinfectant from the recycling process were negative in all of the dose groups. The levels of DNA damage that are caused by different treatment processes were equivalent. Reusing residual sludge for DWTPs did not contribute to the release of genotoxic or mutagenic compounds, but it did have a remarkable effect on saving the drug dose and increasing drinking water yield. Thus, reusing residual sludge for DWTPs should be widely recommended.

摘要

回收饮用水处理厂 (DWTP) 中的残留污泥可能会释放过量的重金属和有机物，这些物质因其有毒和致癌的潜力而备受关注。本研究的目的是研究再生残留污泥对饮用水厂水质的潜在遗传毒性、细胞毒性和诱变效应。使用 Ames 试验、小鼠精子异常试验、微核试验、彗星试验和单细胞凝胶电泳试验评估再利用残余污泥的基因毒性效应。Ames测定结果表明，无论处理方式如何，消毒水样在7 L/dish的剂量下均显示出抑菌作用，但致突变率（MR）<2仍可判断为阴性。常规处理的微核率有轻微的遗传毒性，但仅在 4 和 40 L/kg·bw，而来自回收过程的过滤水和消毒剂的微核率在所有剂量组中均为负值。由不同治疗过程引起的 DNA 损伤水平是相当的。DWTPs 的剩余污泥再利用不会导致遗传毒性或诱变化合物的释放，但它确实对节省药物剂量和增加饮​​用水产量有显着效果。因此，应广泛推荐将残余污泥再用于 DWTPs。DWTPs 的剩余污泥再利用不会导致遗传毒性或诱变化合物的释放，但它确实对节省药物剂量和增加饮​​用水产量有显着效果。因此，应广泛推荐将残余污泥再用于 DWTPs。DWTPs 的剩余污泥再利用不会导致遗传毒性或诱变化合物的释放，但它确实对节省药物剂量和增加饮​​用水产量有显着效果。因此，应广泛推荐将残余污泥再用于 DWTPs。