Trihalomethanes and haloacetamides as disinfection by-products in different types of drinking water of Wuxi / 环境与职业医学

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.

Exposure level and health risk assessment of chlorination disinfectant by-products in drinking water in Xiangyang City / 公共卫生与预防医学

Objective To understand the exposure level of disinfection by-products (DBPs) in drinking water in Xiangyang City and to evaluate the health risks of the population, so as to provide reference for the safety risk control of drinking water. Methods Sampling and laboratory testing were conducted according to national standard methods. The risk assessment model provided by USEPA was used to evaluate the health risks. Results Trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and tribromomethane (TBM) were detected in drinking water in Xiangyang City. The contents of halogenated hydrocarbon DBPs in water disinfected with liquid chlorine were higher than those with chlorine dioxide. The contents of three DBPs were higher in wet season than those in dry season except TBM. The content of TCM in pipe network terminal water and secondary water supply disinfected with chlorine dioxide was higher than that in factory water. The carcinogenic risk of DBPs in drinking water disinfected with liquid chlorine was 4.33×10-5, and the non-carcinogenic risk was 0.114. The carcinogenic risk of DBPs in drinking water disinfected with chlorine dioxide was 1.24×10-6, and the non-carcinogenic risk was 3.15×10-3. Conclusion The health risk of DBPs in drinking water in Xiangyang City is acceptable, but TCM produced by liquid chlorine disinfection should be paid more attention. It is recommended that chlorine dioxide disinfection be used to reduce the health risks of halogenated hydrocarbon DBPs.

Estudo do potencial de formação de trihalometanos na lagoa de Extremoz (RN) / Study of trihalomethanes potencial formation in Extremoz-RN pond

RESUMO O potencial de formação de trihalometanos (PFTHM) é uma metodologia utilizada para avaliar a possibilidade de formação de subprodutos da desinfecção (SPD) por cloração durante o processo de tratamento da água. Trihalometanos (THM) são compostos organoclorados e representam a soma de clorofórmio, diclorobromometano, dibromoclorometano e bromofórmio, sendo a principal classe de SPD formados a partir da reação entre o cloro residual livre e a matéria orgânica natural (MON) presente na água bruta de mananciais de superfície. Esta pesquisa teve como objetivo avaliar o PFTHM resultante da aplicação de cloro na água bruta da lagoa de Extremoz, cuja tecnologia de tratamento utilizada é a filtração direta, seguida de desinfecção com cloro. Os resultados obtidos indicaram presença de matéria orgânica natural hidrofílica com predominância de ácidos fúlvicos na água bruta do manancial. A concentração média de TTHM7 (4,22 mg.L-1) revelou que a água do manancial possui forte potencialidade para formação de compostos orgânicos halogenados. O clorofórmio representou cerca de 80% da concentração total de THM nos ensaios realizados. Foram observadas correlações fortes e significativas entre as variáveis dureza (R = 0,90 e p = 0,005) e cor aparente (R = -0,93 e p = 0,002) da água bruta, resultados que indicaram que íons Ca2+ e Mg2+ podem promover a formação de THM, assim como a cor aparente.

ABSTRACT Trihalomethanes formation potential (THMFP) has been used to evaluate the possibility of disinfection byproduct (DBP) formation by chlorination during the water treatment process. Trihalomethanes (THM) are organochlorine compounds and represents the sum of chloroform, dichlorobromomethane, dibromochloromethane, and bromoform, and is the main class of DBP formed from the reaction between free residual chlorine and natural organic matter (NOM) present in the source waters of surface fountains. This research evaluates the THMFP on the source water from the Extremoz Pond (Natal-RN, Brazil), which is treated by direct filtration followed by chlorine disinfection. Results indicated the presence on source water of hydrophilic natural organic matter with the predominance of fulvic acids. The mean concentration of TTHM7 (4.22 mg.L-1) showed that the source water has a strong potential for halogenated organic compounds formation. Chloroform represented about 80% of the total THM concentration in the assays performed. Significant and strong correlations were observed between hardness (R = 0.90 and p = 0.005) and apparent color (R = -0.93 and p = 0.002) attesting that Ca2+ and Mg2+ ions can promote the formation of THM, as well as the apparent color.

Distribution level and health risk assessment of disinfection by-products in drinking water in China / 公共卫生与预防医学

Objectives To understand the distribution level and health risk of disinfection by-products of drinking water in cities of China, and to provide references for drinking water safety management. Methods By systematically searching the literatures published from 2009 to 2019, the effective data were extracted and the exposure levels of disinfection by-products of drinking water in China was statistically analyzed. The health risk assessment model recommended by EPA was used to conduct risk assessments on THMs and HAAs disinfection by-products. Results The levels of various disinfection by-products were as follows: trihalomethane > haloacetic acid > haloacetonitrile > chloral hydrate > haloketones > nitrosamines. The main disinfection by-products in drinking water in southern China were higher than those in northern China. The total amount of disinfection by-products produced by liquid chlorine disinfection was higher than other disinfection methods. Conclusion The carcinogenic risk of various disinfection by-products in domestic urban drinking water was higher than the acceptable EPA level (1×10-6 ). Sodium hypochlorite disinfection instead of liquid chlorine disinfection was able to effectively reduce the health risk of disinfection by-products to humans. The health risk of the exposure to pollutants in drinking water was higher in children than in adults, which should be taken into special consideration

Monitoramento das concentrações de trihalometanos na água potável / Monitoring the trihalomethanes concentrations in drinking water

The reduction of the incidence of water-borne diseases is achieved with the diffusion of the useof chlorination techniques. However, in spite of the benefits of this disinfection method,the reactions of chlorine with the natural organic matter occurring in the water induce theproduction of disinfection by products such as trihalomethanes. These products have already beenassociated with the incidence of some cancers types. Considering that in the Brazilian legislation,it is not mandatory measuring and controlling the occurrence of trihalomethanes at the exitand during the water distribution to the consumer. This study aimed at analyzing the relationshipbetween chlorination and its by products. Thus, this project evaluated the concentrations oftrihalomethanes in water collected at different points of supply in the municipality of Colombo,Paraná, Brazil, during the period from November 2015 to February 2016. Chromatographicmethods were employed, besides the spreadsheets provided by the Health Surveillance ofColombo for comparison. The found values were tabulated and they were compared with thelimits established by the Brazilian Ministry of Health- Ordinance No 05/2017. The results confirmedthat the values of those provided by the concessionaire responsible for the city water treatmentand supply, and being within the standards determined by the legislation.

A redução da incidência de doenças transmitidas pela água foi alcançada com a difusão douso de técnicas de cloração. Apesar dos benefícios desse método de desinfecção, as reações decloro com a matéria orgânica natural presente na água levam à formação de subprodutos dedesinfecção como trihalometanos. Esses produtos já foram associados à incidência de algunstipos de câncer em animais, e muitas vezes podem ser detectados em água tratada e fornecidapara o consumo. Pela legislação brasileira não é obrigatório efetuar o monitoramento detrihalometanos após o tratamento e distribuição de água. Frente a este problema, este estudoteve como objetivo avaliar as concentrações de trihalometanos em água coletada em diferentespontos de abastecimento no município de Colombo, PR, Brasil, durante o período de novembrode 2015 a fevereiro de 2016. Utilizou-se método cromatográfico para as análises, além deplanilhas fornecidas pela Vigilância Sanitária de Colombo. Todos os valores foram comparadoscom os limites estabelecidos na Portaria de Consolidação Nº 05/2017 do Ministério da Saúde.Os resultados confirmaram que os valores de trihalometanos fornecidos pela concessionária,responsável pelo tratamento e fornecimento de água na cidade, atendem aos parâmetros legais.

Monitoring the trihalomethanes concentrations in drinking water / Monitoramento das concentrações de trihalometanos na água potável

The reduction of the incidence of water-borne diseases is achieved with the diffusion of the use of chlorination techniques. However, in spite of the benefits of this disinfection method, the reactions of chlorine with the natural organic matter occurring in the water induce the production of disinfection by products such as trihalomethanes. These products have already been associated with the incidence of some cancers types. Considering that in the Brazilian legislation, it is not mandatory measuring and controlling the occurrence of trihalomethanes at the exit and during the water distribution to the consumer. This study aimed at analyzing the relationship between chlorination and its by products. Thus, this project evaluated the concentrations of trihalomethanes in water collected at different points of supply in the municipality of Colombo, Paraná, Brazil, during the period from November 2015 to February 2016. Chromatographic methods were employed, besides the spreadsheets provided by the Health Surveillance of Colombo for comparison. The found values were tabulated and they were compared with the limits established by the Brazilian Ministry of Health- Ordinance No 05/2017. The results confirmed that the values of those provided by the concessionaire responsible for the city water treatment and supply, and being within the standards determined by the legislation.

A redução da incidência de doenças transmitidas pela água foi alcançada com a difusão do uso de técnicas de cloração. Apesar dos benefícios desse método de desinfecção, as reações de cloro com a matéria orgânica natural presente na água levam à formação de subprodutos de desinfecção como trihalometanos. Esses produtos já foram associados à incidência de alguns tipos de câncer em animais, e muitas vezes podem ser detectados em água tratada e fornecida para o consumo. Pela legislação brasileira não é obrigatório efetuar o monitoramento de trihalometanos após o tratamento e distribuição de água. Frente a este problema, este estudo teve como objetivo avaliar as concentrações de trihalometanos em água coletada em diferentes pontos de abastecimento no município de Colombo, PR, Brasil, durante o período de novembro de 2015 a fevereiro de 2016. Utilizou-se método cromatográfico para as análises, além de planilhas fornecidas pela Vigilância Sanitária de Colombo. Todos os valores foram comparados com os limites estabelecidos na Portaria de Consolidação Nº 05/2017 do Ministério da Saúde. Os resultados confirmaram que os valores de trihalometanos fornecidos pela concessionária, responsável pelo tratamento e fornecimento de água na cidade, atendem aos parâmetros legais.

Aplicacao da tecnica por cromatografia a gas para investigacao da formacao de sub produtos da desinfeccao em agua potavel / Application of gas chromatographic technique for investigation of the formation of by products in drinking water disinfection

O uso do cloro para a desinfecção e/ou oxidação nas estações de tratamento de água favorece a formação de subprodutos orgânicos halogenados (SOH), muitos deles carcinogênicos. O objetivo desta pesquisa foi validar uma metodologia analítica proposta para a quantificação simultânea de 12 subprodutos da desinfecção por cromatografia a gás com detector de captura de elétrons (CG-DCE). O método apresentou linearidade (r>0,998), repetibilidade menor que 0,15%, limites de detecção de 1 a 6 µg.L-1 e de quantificação de 3 a 21 Î1/4g.L-1, precisão (<10%), exatidão (93-120%) e recuperação (87-117%). Os resultados indicam que o método pode ser empregado para a investigação de SOH em água, garantindo confiabilidade analítica nos resultados.

The use of chlorine for disinfection and/or oxidation at drinking water treatment plants favors the formation of halogenated organic by-products (HOB), many of them carcinogenic. The purpose of this research was to validate an analytical method for the simultaneous quantification of 12 HOB from disinfection by gas chromatograph with electrons capture detector (GC-ECD). The method provided linearity (r>0.998), repeatability lower than 0.15%, limits of detection from 1 to 6 Î1/4g.L-1 and of quantification from 3 to 21 Î1/4g.L-1, precision (<10%), accuracy (93-120%) and recovery (87-117%). The results indicate that the method can be employed to investigate the formation of HOB in water, yielding analytically reliable results.

Chlorination disinfection by-products in drinking water and congenital anomalies: review and meta-analyses / Subprodutos da desinfecção com cloro em água potável e anomalias congênitas: revisão e meta-análise

This study aims to review epidemiologic evidence of the association between exposure to chlorination disinfection by-products (DBPs) and congenital anomalies. All epidemiologic studies that evaluated a relationship between an index of DBP exposure and risk of congenital anomalies were analyzed. For all congenital anomalies combined, the meta-analysis gave a statistically significant excess risk for high versus low exposure to water chlorination or TTHM (17 percent; 95 percent CI, 3-34) based on a small number of studies. The meta-analysis also suggested a statistically significant excess risk for ventricular septal defects (58 percent; 95 percent CI, 21-107), but based on only three studies, and there was little evidence of an exposure-response relationship. It was observed no statistically significant relationships in the other meta-analyses and little evidence for publication bias, except for urinary tract defects and cleft lip and palate. Although some individual studies have suggested an association between chlorination disinfection by-products and congenital anomalies, meta-analyses of all currently available studies demonstrate little evidence of such association.

O objetivo deste estudo é revisar evidências epidemiológicas da associação entre a exposição a subprodutos da desinfecção com cloro (DBPs) e anomalias congênitas. Todos os estudos epidemiológicos que avaliaram a relação entre o índice de exposição a DBPs e o risco de anomalias congênitas foram analisados. Para todas as anomalias congênitas combinadas, a meta-análise resultou em um risco de excesso estatisticamente significante para alta versus baixa exposição à cloração da água ou ao TTHM (17 por cento; 95 por cento CI, 3-34) baseado em um pequeno número de estudos. A meta-análise também sugere um excesso de risco estatisticamente significante para defeitos septais ventriculares (58 por cento; 95 por cento CI, 21-107), porém com base em apenas três estudos, nos quais se encontrou pouca evidência na relação exposição-resposta. Não foram observadas relações estatisticamente significantes em outras meta-análises e pouca evidência para uma tendência de publicação, com exceção de defeitos no trato urinário e fissura labiopalatal. Apesar de alguns estudos individuais sugerirem uma associação entre subprodutos da desinfecção com cloro e anomalias congênitas, as meta-análises de todos os estudos disponíveis atualmente demonstraram pouca evidência de tal associação.

Effect of Chloramine Disinfection on the Formation of Drinking Water Disinfection By-Products and Their Muta-genicity / 环境与健康杂志

Objective To assess the effect of chloramine disinfection on the formation of drinking water disinfection by-products(DBPs )and their mutagenicity.Methods The bacterial indices,chloroform and carbon tetrachloride content in the finished water samples using liquid chlorine and chloramine disinfection respectively were determined in August,2001(plentiful water season)and in March,2002(low water season).The mutagenicities of organic extracts from the water samples were tested using Ames test.The levels of DBPs and the mutagenic activities of water samples treated with different disinfection methods were compared.Results The total count of bateria and coliform bacteria were0/ml and0/L respectively at free chlorine con-centration of about 1mg /L in the chloraminated drinking water,which decreased81%-84%compared with those of the chlori-nated drinking water samples.The carbon tetrachloride concetration were all

DNA Damage Induced by Chlorinated Acetic Acids, the Drinking Water Disinfection By-products / 环境与健康杂志

Objective To study the DNA damage induced by dichloroacetic acid(DCA) and trichloroacetic acid(TCA) which are from drinking water disinfection by-products. Methods V79 cells and hepatocytes of mice were treated with DCA and TCA for 1 hour and then were tested by comet assay. After stained by EB, tail length of the cells were observed and counted under the fluorescence microscope. Results Both DCA and TCA could result in the increasing of average tail length of the treated cells whether they were V79 cells or hepatocytes of mice and the dose-response relationships were seen. Conclusion Both DCA and TCA can cause DNA damage of mammalian cells and this may be related to the carcinogenic mechanism. DCA and TCA belong to genetic carcinogens.