Zhan Yuehao, Zeng Xuefeng, Chu Wenhai, Wei Xiao, Chen Xiaohong, Liu Bingjun, Hur Kyu, Dong Shengkun
Guangdong Engineering Technology Research Center of Water Security Regulation and Control for Southern China, School of Civil Engineering, Sun Yat-sen University, Guangzhou 510275, China.
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Environ Sci Technol. 2024 Sep 10. doi: 10.1021/acs.est.4c08404.
Toxicity studies of water disinfection byproducts (DBPs) typically assume additive interactions. Coupling results from both the bottom-up cytotoxicity interaction approach by selecting six common DBPs and the top-down cytotoxicity fractionating the disinfected secondary effluent containing a much broader DBP selection, we demonstrated a novel effect of clear, nonadditive cytotoxicity at low chemical concentrations regardless of the number of DBP types involved. We revealed that the cytotoxicity interactions were influenced by the chemical's type, concentration factor, and mixing ratio. For the bottom-up approach, the average combination indices (CIs) were 1.61 (chloracetamide + chloroacetonitrile, antagonism), 1.03 (bromoacetamide+bromoacetonitrile, near additivity), and 0.69 (iodoacetamide + iodoacetonitrile, synergism) across the DBPs' concentration range of 10-10 M. These cytotoxicity interactions also varied with the components' mixing ratios. For the top-down approach, we obtained two fractions of DBP mixtures from the disinfected secondary effluent using solvents of different polarities. The effect of the concentration on CI values was significant, with a maximum 43.1% relative deviation in CI from LC to LC. The average CI values across the sample concentration range of 1-50 × (concentration factor) varied from 1.68 (antagonism) to 0.89 (slight synergism) as the ratio of mixture A increased. These results call for further research in prioritizing the forcing DBPs in mixtures.
水消毒副产物（DBPs）的毒性研究通常假定存在加和性相互作用。通过选择六种常见的消毒副产物，采用自下而上的细胞毒性相互作用方法，并对含有更广泛消毒副产物种类的消毒二级出水进行自上而下的细胞毒性分级，我们证明了在低化学浓度下存在一种明显的、非加和性细胞毒性的新效应，而与所涉及的消毒副产物类型数量无关。我们发现细胞毒性相互作用受化学物质的类型、浓度因子和混合比例的影响。对于自下而上的方法，在10⁻¹⁰ M的消毒副产物浓度范围内，平均组合指数（CIs）分别为1.61（氯乙酰胺 + 氯乙腈，拮抗作用）、1.03（溴乙酰胺 + 溴乙腈，接近加和性）和0.69（碘乙酰胺 + 碘乙腈，协同作用）。这些细胞毒性相互作用也随组分的混合比例而变化。对于自上而下的方法，我们使用不同极性的溶剂从消毒二级出水中获得了两部分消毒副产物混合物。浓度对组合指数值的影响显著，从低浓度到高浓度，组合指数的最大相对偏差为43.1%。随着混合物A比例的增加，在1 - 50×（浓度因子）的样品浓度范围内，平均组合指数值从1.68（拮抗作用）变化到0.89（轻微协同作用）。这些结果呼吁在对混合物中强效消毒副产物进行优先级排序方面开展进一步研究。
