Department of Chemistry and Biochemistry, University of South Carolina, Columbia 29208, South Carolina, United States.
Department of Occupational and Environmental Health, School of Public Health, Soochow University, Suzhou 215123, China.
Environ Sci Technol. 2022 Aug 16;56(16):11387-11397. doi: 10.1021/acs.est.2c02490. Epub 2022 Aug 8.
Although >700 disinfection by-products (DBPs) have been identified to date, most DBPs in drinking water are still unknown. Identifying unknown DBPs is an important step for improving drinking water quality because known DBPs do not fully account for the adverse health effects noted in epidemiologic studies. Using gas chromatography high-resolution mass spectrometry, six chloro- and bromo-halocyclopentadienes (HCPDs) were identified in chlorinated and chloraminated drinking water non-target analysis; five HCPDs are reported for the first time as new alicyclic DBPs. Formation pathways were also proposed. Simulated disinfection experiments with Suwannee River natural organic matter (NOM) confirm that NOM is a precursor for these new DBPs. Further, HCPDs are more abundant in chlorinated drinking water (real and simulated) when compared to chloraminated drinking water due to the higher reactivity of chlorine. Of these new DBPs, 1,2,3,4,5,5-hexachloro-1,3-cyclopentadiene is approximately 100,000× more toxic () than regulated trihalomethanes (THMs) and haloacetic acids (HAAs) and 20-2000× more toxic than halobenzoquinones, halophenols, and halogenated pyridinols using the available median lethal dose (LD) and concentration for 50% of maximal effective concentration (EC) of DBPs to aquatic organisms. The predicted bioconcentration factors of these HCPDs range from 384 to 3980, which are 2-3 orders of magnitude higher than those for regulated and priority DBPs (including THMs, HAAs, halobenzoquinones, haloacetonitriles, haloacetamides, halonitromethanes, haloacetaldehydes, iodo-THMs, and iodo-HAAs). Thus, HCPDs are an important emerging class of DBPs that should be studied to better understand their impact on drinking water quality and long-term human health exposure.
尽管迄今为止已经鉴定出超过 700 种消毒副产物 (DBPs)，但饮用水中的大多数 DBPs 仍然未知。鉴定未知的 DBPs 是提高饮用水质量的重要步骤，因为已知的 DBPs 并不能完全解释流行病学研究中观察到的不良健康影响。在非靶向分析中，使用气相色谱高分辨率质谱法，在氯化和氯胺化饮用水中鉴定出六种氯和溴卤代环戊二烯（HCPD）；其中五种 HCPD 首次作为新的脂环族 DBPs 被报道。还提出了形成途径。使用苏万尼河天然有机物 (NOM) 进行模拟消毒实验证实，NOM 是这些新 DBPs 的前体。此外，由于氯的反应性更高，与氯胺化饮用水相比，氯化饮用水（实际和模拟）中 HCPD 更为丰富。在这些新的 DBPs 中，1,2,3,4,5,5-六氯-1,3-环戊二烯的毒性（LC50）比受管制的三卤甲烷 (THMs) 和卤乙酸 (HAAs) 高约 100,000 倍，比卤代苯醌、卤代酚和卤代吡啶醇的毒性高 20-2000 倍，使用现有半致死剂量 (LD) 和 50%最大有效浓度 (EC) 的 DBPs 对水生生物的浓度。这些 HCPD 的预测生物浓缩因子范围为 384 至 3980，比受管制和优先 DBPs（包括 THMs、HAAs、卤代苯醌、卤代乙腈、卤代乙酰胺、卤代硝基甲烷、卤代乙醛、碘代 THMs 和碘代 HAAs）高 2-3 个数量级。因此，HCPD 是一类重要的新兴 DBPs，应该进行研究，以更好地了解它们对饮用水质量和长期人类健康暴露的影响。
