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Dissolved black carbon (DBC), the soluble component of black carbon, which mainly comes from the incomplete combustion of fossil fuels or biomass, is widely spread in source water and significantly contributes to the formation of dissolved organic matter (DOM). However, the origin of DBC in different types of source water in China has not been well studied, as well as its subsequent transformation and toxicity contribution during disinfection of source water DOM by chlor(am)ine. In this study, DBC from 17 different source water in East China at different seasons was collected. The δ 13 C compositions indicated that straw burning was the main origin of DBC in source water. After simulated chlor(am)ination of DBC, 5 categories of aliphatic disinfection byproducts (DBPs) including trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, halonitromethanes and 6 categories of aromatic DBPs including halophenols, halonitrophenols, halohydroxybenzaldehyde, halohydroxybenzoic acid, halobenzoquinones and haloaniline were detected. Compared with chlorination of DBC, higher levels of nitrogenous DBPs and aromatic DBPs were generated during chloramination. Detected DBPs accounted for 42 % of total organic halogen. What's more, Chinese hamster ovary cells cytotoxicity tests showed that the cytotoxicity of DBPs formed by chlor(am)ination of DBC was 4 times higher than that by chlor(am)ination of DOM. Haloacetonitriles contributed to the highest cytotoxicity in the chloramination of DBC, and haloacetic acids contributed to the highest cytotoxicity in chlorination. 67 % of the total cytotoxicity attributed to the undetected DBPs. As a result, DBPs generated from DBC contributed to 11.7 % of the total cytotoxicity in the chlor(am)ination of the source water DOM although DBC only took up 2 % of DOC in the source water. Results obtained from this study systematically revealed the DBPs formation from DBC and their potential cytotoxicity contribution in the chlor(am)ination of source water DOM, which should not be ignored in drinking water treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Haloacetaldehyde disinfection by-products (HAL-DBPs) are among the top three unregulated DBPs found in drinking water. The cytotoxicity and genotoxicity of HALs are much higher than that of the regulated trihalomethanes and haloacetic acids. Previous studies have mainly focused on the toxic effects of single HAL, with few examining the toxic effects of mixed exposures to HALs. The study aimed to observe the effects of mixed exposures of 1∼1000X the realistic level of HALs on the hepatotoxicity and lipid metabolism of C57BL/6J mice, based on the component and concentration of HALs detected in the finished water of Shanghai. Exposure to realistic levels of HALs led to a significant increase in phosphorated acetyl CoA carboxylase 1 (p-ACC1) in the hepatic de novo lipogenesis (DNL) pathway. Additionally, exposure to 100X realistic levels of HALs resulted in significant alterations to key enzymes of DNL pathway, including ACC1, fatty acid synthase (FAS), and diacylglycerol acyltransferase 2 (DGAT2), as well as key proteins of lipid disposal such as carnitine palmitoyltransferase 1 (CPT-1) and peroxisome proliferator activated receptor α (PPARα). Exposure to 1000X realistic levels of HALs significantly increased hepatic and serum triglyceride levels, as well as total cholesterol, low-density lipoprotein, alanine aminotransferase, aspartate transaminase, alkaline phosphatase, and lactate dehydrogenase levels, significantly decreased high-density lipoprotein. Meanwhile, histopathological analysis demonstrated that HALs exacerbated tissue vacuolization and inflammatory cell infiltration in mice livers, which showed the typical phenotypes of non-alcoholic fatty liver disease (NAFLD). These results suggested that the HALs mixture is a critical risk factor for NAFLD and is significantly highly toxic to C57BL/6J mice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Spatial distributions, levels, and comprehensive assessments of post-flood tap water disinfection by-products (DBPs) were first studied in Henan Province after the "7.20" Extreme Rainstorm Event in 2021. DBPs levels and health risks in tap water were higher in areas flooded (waterlogged) by storm or upstream flood discharge (WA) and rainstorm-affected areas (RA) compared with other areas (OA), suggesting that extreme rainstorm and flooding events may somehow exacerbate DBPs contamination of tap water through disinfection. WA sites were characterized as contamination hotspots. The results revealed high haloacetic acids (HAAs) levels in WA (Avg: 57.79 μg·L -1 ) and RA (Avg: 32.63 μg·L -1 ) sites. Compared with normal period, DBPs-caused cancer risk increased by 3 times, exceeding the negligible risk level. Cancer risk came primarily from the ingestion of trihalomethanes (THMs) (>80%), children were the sensitive group. Those between 30 and 69 showed approximately 1.7 times higher disability-adjusted life yearsper person-yearthan other age groups. Apart from regulated DBPs, bromochloracetic acid (BCAA) and dibromoacetonitrile (DBAN) appear to be the main toxicity contributors in these samples. Our results provide a scientific basis for preventing and controlling health risks from tap water DBPs and for assessing the social benefits and burdens of emergency disinfection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Halobenzoquinones (HBQs) are emerging unregulated drinking water disinfection byproducts (DBPs) that are more toxic than regulated DBPs. This study aimed to determine the distribution and formation of HBQs in drinking water from water treatment plants in China, compare their chronic cytotoxicity and their induction of chromosomal damage in Chinese hamster ovary cells, and analyze the correlation of HBQ toxicity with their physicochemical parameters. Two HBQs, 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ) and 2,6-dibromo-1,4-benzoquinone (2,6-DBBQ), were detected in finished water and tap water in China. The concentrations were in the ranges of <2.6-19.70 ng/L for 2,6-DCBQ and <0.38-1.8 ng/L for 2,6-DBBQ. Chemical oxygen demand and residual chlorine were positively correlated with HBQ formation. The HBQ concentration was lower in a drinking water treatment plant using chlorine dioxide. High Ca 2+ in tap water decreased the HBQ level. The rank order of HBQ by cytotoxicity was 2-chloro-1,4-benzoquinone > 2,3-diiodo-1,4-benzoquinone > 2,6-diiodo-1,4-benzoquinone > 2,6-dibromo-1,4-benzoquinone > 2,5-dibromo-1,4-benzoquinone > 2,5-dichloro-1,4-benzoquinone > 2,6-dichloro-1,4-benzoquinone > tetrachloro-1,4-benzoquinone > 2,3,6-trichloro-1,4-benzoquinone, and for their genotoxicity, 2,5-dichloro-1,4-benzoquinone > 2,6-dichloro-1,4-benzoquinone > 2,3-diiodo-1,4-benzoquinone > 2,6-diiodo-1,4-benzoquinone > tetrachloro-1,4-benzoquinone > 2,5-dibromo-1,4-benzoquinone > 2,6-dibromo-1,4-benzoquinone > 2,3,6-trichloro-1,4-benzoquinone. The cytotoxicity of six dihalo-HBQs was negatively correlated with the octanol-water partition coefficient (r = -0.971, P < 0.05), molar refractivity (r = -0.956, P < 0.05), energy of the highest occupied molecular orbital (E HOMO ) (r = -0.943, P < 0.05), and polar surface area (r = -0.829, P < 0.05). The genotoxicity of these three pairs of dihalo-HBQ isomers followed the same order as their E HOMO values. This study reveals the occurrence and formation of HBQs in drinking water in China and systematically evaluates the chromosomal damage caused by nine HBQs in mammalian cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Swimming pool disinfection byproducts (DBPs) are becoming increasingly common worldwide. Precise exposure and health risk assessment for DBPs in swimming pool water with optimized parameters for local and specific population is more urgently needed. This study aimed to determine the levels of trihalomethanes (THMs) and haloacetic acids (HAAs) in 16 public indoor swimming pools in Shanghai, China. Swimming habits were also investigated to obtain more accurate exposure assessment parameters. Precise exposure assessment through multiple pathways, resulting cancer risk, and disability-adjusted life years (DALYs) were assessed. Results indicated that the highest total level of THMs and HAAs occurred in autumn. The surveyed swimmers 9-17 years of age had higher average daily dose (ADD) of DBPs than swimmers ≥18 years of age. The total lifetime cancer risk (LCR) attributable to THMs and HAAs exceeded 10 -6 , which represents a negligible risk level (NRL). The cancer risk from inhalation exposure predominantly by THMs contributed more than 99% of the total risk. Annual disease burden was 19.0 person-years attributed to exposure of DBPs in swimming pool water in Shanghai. This study provides a paradigm and strategic reference of precise exposure assessments, risk assessments, and disease burden estimation of hazards in swimming pool water for other regions., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Polyhexamethylene guanidine (PHMG) is a high molecular guanidine compound with a broad spectrum of antibacterial effects. Since the outbreak of the 'humidifier disinfectant-induced lung injury' event in South Korea, the respiratory toxicity of PHMG had become a public concern. An epidemiological survey in Korea found that PHMG-containing disinfectants were an important risk factor for pulmonary fibrosis. Animal experiments also showed that the exposure to PHMG through the respiratory tract could cause irreversible fibrosis in the lungs. TGF-β signaling pathway, epithelial-mesenchymal transition and pulmonary inflammation might be the main pathways that could mediate PHMG-induced pulmonary fibrosis. This article provided an overview of the characteristics of population exposure to PHMG and research progress in the field of respiratory toxicology and recommendations for the rational and standard of using PHMG-related products in China.

This article summarized the use of guanidine disinfectants in China and the use of guanidine cationic disinfectants, polyhexamethylene guanidine (PHMG), in South Korea, which had caused severe lung damage events such as pulmonary fibrosis. The authors reviewed the studies that Chinese scientists employed ultrasonic atomization technology to simulate the actual scenario of human exposure to PHMG and proved the findings that PHMG could cause pulmonary fibrosis. These results could highlight the necessity of full attention to lung damage caused by guanidine disinfectants and its mechanism, so as to provide the important scientific basis for the protection of public health safety and the formulation of corresponding policies.

Harmful algal blooms (HABs) and the invasion of smooth cordgrass (Spartina alterniflora) have become important environmental problems in intertidal zones of China, which caused serious damage on the coastal ecological systems. By using S. alterniflora as algaecide, this helps to utilize this invasive plant, in addition, is expected to help to control the expansion of S. alterniflora. The potential of S. alterniflora in HABs mitigation was investigated on controlling Phaeocystis globosa (haptophyceae) and Prorocentrum donghaiense (dinophyceae). The growth of both HABs species was significantly inhibited at high concentrations, and P. globosa was more sensitive than P. donghaiense. Furthermore, the extracts of S. alterniflora reduced the effective quantum yield, photosynthetic efficiency, and relative maximal electron transport rate of both algal species at high concentrations, which implies a disruption on their photosynthetic system. Flavonoids, which were previously known as antialgal chemicals, were found to be abundant in the extracts of S. alterniflora by UPLC-MS detection. Our results revealed that the potential of S. alterniflora as a novel antialgal agent for controlling HABs, simultaneously, resource utilization possibility for the invasive plant S. alterniflora., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The occurrence and transformation behaviors of disinfection byproducts (DBPs) were investigated in the finished water and tap water of 14 water treatment plants in rural areas of eastern China. Mammalian cell toxicity data from previous studies were used to evaluate the cytotoxicity of trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), trichloronitromethane (TCNM) and the genotoxicity of HAAs, HANs and TCNM. Correlation analysis was conducted to identify the factors that might influence the variability of DBPs. The measured median values were 29.76 μg/L for THMs, 20.47 μg/L for HAAs, 3.98 μg/L for HANs, 0.76 μg/L for haloketones (HKs) and 0.03 μg/L for TCNM. The spatial variability analysis showed that the total concentrations of HAAs and HANs decreased during long hydraulic residence time (HRT) in seven drinking water distribution systems, which could result in reduced mammalian cell cytotoxicity and genotoxicity at consumers' taps. The concentrations of trihalogenated-DBPs were more stable than those of dihalogenated-DBPs and monohalogenated-DBPs during long HRT. Bromine acted as a more efficient substituting agent than chlorine for THMs and dihaloacetonitriles (DHANs) in actual drinking water. The dominant chlorinated-THMs and chlorinated-DHANs would transfer to brominated -THMs and brominated-DHANs when the concentration of bromide ion exceeds 450.67 and 610.25 μg/L, respectively. Correlation analysis indicated that particulate and soluble manganese (Mn) might play critical roles in promoting the production of DBPs in bulk water. Hydraulic disturbance could also result in secondary release of DBPs from loose deposits accumulated on distribution pipe walls., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objective: To explore the associations between exposure to chlorination disinfection by-products (CDBPs) during gestation and newborns' small for gestational age (SGA). Methods: During April 2010 to July 2012, a total of 3 903 pregnant women who lived in a district with the same water treatment plant in Wuhan, China were recruited to this perspective study. Information about demographic characteristics of pregnant women and their newborns was collected. The tap water samples were monthly collected for 28 months in 3 different sites, with 84 samples, and 4 kinds of trihalomethanes (THMs)(chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)) and 2 kinds of chlorohaloacetic acids (HAAs) (trichloroacetic acid (TCAA), dichloroacetic acid (DCAA)) were determined. The pregnant women were divided into 4 groups(Q1 to Q4) by quartile method according to their exposure level of CDBPs. Binary Logistic regression models were used to assess the associations between exposure to CDBPs during gestation and newborns' small for gestational age. Results: The average weight of all the newborns was (3 310.19±389.91) g, of which 169 (4.33%) were SGA. The median concentrations of TCM, BDCM, bromo-THMs, total THMs, TCAA, and DCAA during the whole pregnancy were 18.07, 4.93, 8.51, 26.74, 10.65, and 13.77 μg/L, respectively. Binary Logistic regression analysis showed dose-response relationships between elevated TCM and total THMs during the whole gestation and compared with Q1 group, while there was a increased risk of SGA in Q4 group, and OR (95 %CI ) was 1.87 (1.01-3.49) , 2.30 (1.22-4.35) , respectively ( P for trend equaled to 0.044, 0.015). Compare with Q1 group, there also be positive associations between exposure to TCAA (Q4 group) during first-trimester and the whole gestation and SGA, while OR (95 %CI ) was 2.16 (1.19-3.91) ( P for trend equaled to 0.015). Conclusion: Exposure to CDBPs during gestation might increase the risk of newborns' SGA.

Background: Exposure to disinfection by-products (DBPs) has been demonstrated to impair male reproductive health in animals, but human evidence is limited and inconsistent., Objective: We examined the association between exposure to drinking-water DBPs and semen quality in a Chinese population., Methods: We recruited 2,009 men seeking semen analysis from the Reproductive Center of Tongji Hospital in Wuhan, China, between April 2011 and May 2012. Each man provided a semen sample and a urine sample. Semen samples were analyzed for sperm concentration, sperm motility, and sperm count. As a biomarker of exposure to drinking-water DBPs, trichloroacetic acid (TCAA) was measured in the urine samples., Results: The mean (median) urinary TCAA concentration was 9.58 (7.97) μg/L (interquartile range, 6.01-10.96 μg/L). Compared with men with urine TCAA in the lowest quartile, increased adjusted odds ratios (ORs) were estimated for below-reference sperm concentration in men with TCAA in the second and fourth quartiles (OR = 1.79; 95% CI: 1.19, 2.69 and OR = 1.51; 95% CI: 0.98, 2.31, respectively), for below-reference sperm motility in men with TCAA in the second and third quartiles (OR = 1.46; 95% CI: 1.12, 1.90 and OR = 1.30; 95% CI: 1.00, 1.70, respectively), and for below-reference sperm count in men with TCAA in the second quartile (OR 1.62; 95% CI: 1.04, 2.55). Nonmonotonic associations with TCAA quartiles were also estimated for semen parameters modeled as continuous outcomes, although significant negative associations were estimated for all quartiles above the reference level for sperm motility., Conclusion: Our findings suggest that exposure to drinking-water DBPs may contribute to decreased semen quality in humans.

Toxicological studies indicate an association between exposure to disinfection by-products (DBPs) and impaired male reproductive health in animals. However, epidemiological evidence in humans is still limited. We conducted a hospital-based cross-sectional study to investigate the effect of exposure to DBPs on semen quality in humans. Between May 2008 and July 2008, we recruited 418 male partners in sub-fertile couples seeking infertility medical instruction or assisted reproduction services from the Tongji Hospital in Wuhan, China. Major semen parameters analyzed included sperm concentration, motility, and morphology. Exposure to DBPs was estimated by their urinary creatinine-adjusted trichloroacetic (TCAA) concentrations that were measured with the gas chromatography/electron capture detection method. We used linear regression to assess the relationship between exposure to DBPs and semen quality. According to the World Health Organization criteria (<20 million/mL for sperm concentration and <50% motile for sperm motility) and threshold value recommended by Guzick (<9% for sperm morphology), there were 265 men with all parameters at or above the reference values, 33 men below the reference sperm concentration, 151 men below the reference sperm motility, and 6 men below the reference sperm morphology. The mean (median) urinary creatinine-adjusted TCAA concentration was 9.2 (5.1) μg/g creatinine. Linear regression analyses indicated no significant association of sperm concentration, sperm count, and sperm morphology with urinary TCAA levels. Compared with those in the lowest quartile of creatinine-adjusted urinary TCAA concentrations, subjects in the second and third quartiles had a decrease of 5.1% (95% CI: 0.6%, 9.7%) and 4.7% (95% CI: 0.2%, 9.2%) in percent motility, respectively. However, these associations were not significant after adjustment for age, abstinence time, and smoking status. The present study provides suggestive but inconclusive evidence of the relationship between decreased sperm motility and increased urinary TCAA levels. The effect of exposure to DBPs on human male reproductive health in Chinese populations still warrants further investigations., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Because of the daily and life-long exposure to disinfection by-products formed during drinking water treatment, potential adverse human health risk of drinking water disinfection is of great concern. Toxicological studies have shown that drinking water treatment increases the genotoxicity of surface water. Drinking water treatment is comprised of different potabilization steps, which greatly influence the levels of genotoxic products in the surface water and thus may alter the toxicity and genotoxicity of surface water. The aim of the present study was to understand the influence of specific steps on toxicity and genotoxicity during the treatment of surface water in a water treatment plant using liquid chlorine as the disinfectant in China. An integrated approach of the comet and oxidative stress assays was used in the study, and the results showed that both the prechlorination and postchlorination steps increased DNA damage and oxidative stress caused by water extracts in human derived L-02 cells while the tube settling and filtration steps had the opposite effect. This research also highlighted the usefulness of an integrated approach of the comet and oxidative stress assays in evaluating the genotoxicity of surface water during drinking water treatment., (Copyright 2009 Wiley-Liss, Inc.)

The occurrences of trihalomethanes (THMs) and haloacetics (HAAs) in the water supply in Beijing and Canada were investigated. The concentrations of THMs and HAAs in Beijing and Canada were below the maximum contaminant levels specified by the USEPA and WHO standards. The multi-pathway risk assessment (assessed through oral ingestion, dermal absorption and inhalation exposure to drinking water) was used to assess the cancer risk and the hazard index of THMs and HAAs from fifteen waterworks in Beijing, China and three treatment plants using different disinfection processes in Canada. Residents in Beijing and residents who were served by three treatment plants using different disinfection processes in Canada had a higher risk of cancer through oral ingestion than through the other two pathways. The cancer risk resulted from disinfection by-products (DBPs) was 8.50E-05(for males), 9.25E-05(for females) in Beijing, China, while it was 1.18E-04, 1.44E-04 in Canada. The risk was higher when water treatment plants used surface water source than when they used ground water source and mixture water source in Beijing. The risk showed different changes in three treatment plants using different disinfection processes in Canada. The lifetime cancer risk for THMs followed the order: Plant 2>Plant 1>Plant 3. And, the lifetime cancer risk for HAAs was: Plant 1>Plant 2>Plant 3.

Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.