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Background The concentrations of disinfection by-products (DBPs) are varied by different water sources, disinfectants, or treatment processes in Wuxi, and the associated health risks are also different. Objective To understand the levels of trihalomethanes (THMs) and haloacetamides (HAcAms) in drinking water in Wuxi, and their variations by water sources, seasons, disinfectants or treatment processes, aiming to provide technical support for ensuring the safety of drinking water. Methods In dry period (December 2019) and wet period (July 2020), the finished water and tap water (from the beginning, middle, and end of the drinking water distribution network) from 12 centralized water treatment plants in Wuxi were collected to detect the concentrations of THMs and HAcAms in water samples. A purge and trap-gas chromatography-mass spectrometry method was applied to detect trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and tribromomethane (TBM), and a solid-phase extraction-gas chromatography-mass spectrometry method to detect dichloroacetamide (DCAcAm), trichloroacetamide (TCAcAm), bromochloroacetamide (BCAcAm), dibromoacetamide (DBAcAm), bromodichloroacetamide (BDCAcAm), dibromochloroacetamide (DBCAcAm), and tribromoacetamide (TBAcAm). Analyses and comparisons were made on the concentrations of THMs and HAcAms in drinking water by water sources (the Yangtze River/the Taihu Lake/reservoir), wet/dry seasons, disinfection methods (liquid chlorine/sodium hypochlorite), and treatment processes (conventional treatment/conventional+advanced treatment). Results A total of 96 drinking water samples were collected in Wuxi. THMs were positive in all the water samples (100%), with concentration ranging from 1.027 to 40.225 μg·L−1 and the M (P25, P75) concentration being 24.782 (17.784, 30.932) μg·L−1. None of the 4 THMs exceeded the standard limit of the Standards for drinking water quality (GB 5749-2022 ), and the order of the 4 THMs concentrations from high to low was TCM > BDCM > DBCM > TBM. Five of the 7 HAcAms were detected, the total concentration ranged from 0.137 to 3.288 μg·L−1, and the M (P25, P75) was 0.808 (0.482, 1.704) μg·L−1. The DCAcAm concentration was the highest (2.448 μg·L−1), followed by BCAcAm, while TCAcAm and DBCAcAm were not detected. The M (P25, P75) of the total concentration of THMs in the drinking water from the Taihu Lake was 33.353 (26.649, 36.217) μg·L−1, that of the Yangtze River was 27.448 (24.312, 31.393) μg·L−1, and both were higher than the level of the reservoir [16.359 (2.305, 21.553) μg·L−1] (P<0.05), while the M (P25, P75) of the total concentration of HAcAms in the drinking water from the Taihu Lake was 0.616 (0.363, 0.718) μg·L−1, which was lower than those of the Yangtze River [0.967 (0.355, 2.283) μg·L−1] and the reservoir [1.071 (0.686, 1.828) μg·L−1] (P<0.05). There were no statistically significant differences in the total concentrations of THMs and HAcAms between wet season and dry season, or between different disinfection methods (P>0.05). The M (P25, P75) concentrations of THMs and HAcAms in drinking water after advanced treatment process involving ozone, activated carbon, and membrane were 20.565 (3.316, 27.185) μg·L−1 and 0.623 (0.452, 1.286) μg·L−1 respectively, and were lower than the corresponding values after conventional treatment process, 28.740 (23.431, 35.085) μg·L−1 and 0.934 (0.490, 2.116) μg·L−1 respectively (P＜0.05). Conclusion The concentrations of THMs and HAcAms in drinking water in Wuxi are generally at a low level. The levels of controlled THMs meet the requirements of national standards, and the levels of uncontrolled HAcAms as new DBPs are up to μg·L−1. The concentrations of the two kinds of DBPs in drinking water vary by water sources. The concentrations of THMs and HAcAms produced by the advanced treatment process are lower than that by the conventional treatment process.
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Objective@#To establish a liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for the determination of microcystin-LR (MC-LR) in drinking water, investigate its removal efficiency during tap water advanced treatment process and analyze its degradation products in the tap water.@*Methods@#Two parallel water samples were collected from each point of tap water advanced treatment process in September 2015, November 2015 and January 2016, respectively, and treated by mixing, filtration, concentration, elution, nitrogen blow and re-dissolvement. The samples were analyzed by LC/MS/MS to determine the MC-LR concentration and its removal efficiency during treatment process. The combination of actual water enrichment (including source water enrichment of 50 times and 1 500 times concentrated, finished water enrichment of 50 times and 2 500 times concentrated) and laboratory simulated water (including the mixture of MC-LR and liquid chlorine in the mass ratio of 1∶10, 1∶20, 1∶100 and 1∶1 000, respectively) were used to qualitative analyze the MC-LR degradation products by Orbitrap mass spectrometry.@*Results@#The linearity of MC-LR ranged from 2 to 200 μg/L with the detection limit of 0.007 9 μg/L and the limit of quantification of 0.026 3 μg/L. The recovery rate of MC-LR from different contration in drinking water were from 94.88%-101.47%. The intra-day precision was 2.51%-7.93% and the intra-day precision was 3.24%-8.41%. The average concentration of MC-LR in source water was (0.631±0.262) μg/L, 94.0% of which can be removed by ozone exposure while the concentrate was (0.038±0.016) μg/L, biological pre-treatment and chlorination. The remaining can hardly be removed by sand filtration, ozone exposure, activated carbon, ultrafiltration and other processes. The MC-LR average concentration in the finished water maintained at about (0.036±0.016) μg/L. Degradation products including hydroxy-microcystin, methyl-hydroxy-microcystin, methyl-microcystin were identified in the laboratory simulated water of the mixture of MC-LR and liquid chlorine in the mass ratio of 1∶10.@*Conclusion@#The established MC-LR detection method can be well applied to the monitoring of MC-LR in drinking water due to its simple pre-treatment process and good methodological validation parameters. The degradation products of treatment processes was different.
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<p><b>OBJECTIVE</b>To explore the correlation between four tagSNPs of Eppin gene (rs6124715, rs2231829, rs2227290 and rs11594) and the risk of idiopathic male infertility in the Chinese Han population.</p><p><b>METHODS</b>A total of 473 confirmed infertile patients (from March 2005 to March 2007) and 198 fertile male controls (March 2005 to February 2009) were selected from two hospitals in Nanjing. All the subjects were Han Chinese and came from Nanjing or its surrounding areas. 5 ml peripheral blood was drawn from each subject with informed consent. Four tagSNPs (rs6124715, rs2231829, rs2227290 and rs11594) in Eppin gene were analyzed by the PCR-restriction fragment length polymorphisms (PCR-RFLP) method. The serum testosterone level was evaluated by radioimmunoassay (RIA).</p><p><b>RESULTS</b>The genotype frequencies of AA,AC and CC at rs11594 were 76.3% (361/473), 20.1% (95/473) and 3.6% (17/473) respectively in the case group, while the frequencies in the control group were 75.3% (149/198), 24.2% (48/198), 0.5% (1/198) respectively, the differences were statistically significant (χ² = 7.73, P = 0.021), the CC genotype carriers had an increased risk of male infertility (OR = 7.02, 95% CI:0.93-53.19). In the combined genotype analysis, the haplotype CTGA carriers has significantly lower onset risk (OR = 0.18, 95% CI:0.06-0.53). In the two groups, the frequencies and the risk of male infertility were no statistically significant in rs6124715, rs2231829 and rs2227290 genotype.</p><p><b>CONCLUSIONS</b>The Eppin gene polymorphisms were correlated to the susceptibility to idiopathic male infertility. Among them, CC genotype at rs11594 could increase the risk of idiopathic male infertility.</p>