环境卫生与监测

051305饮用水氯化消毒副产物与出生缺陷(综述)/吴源…∥疾病控制杂志.2003,7(6).527～530饮用水氯化消毒处理过程中可形成多种类型的消毒副产物(DBPs),包括三卤甲烷、卤代乙酸、卤代乙腈、卤代酮及氯代呋喃酮等。一系列研究显示DBPs与神经管缺陷、先天性心脏病、泌尿系统畸形、     

消毒副产物三氯甲烷与膀胱癌的关系

正氯化消毒(chlorination)是饮用水加工过程中使用最广泛的消毒方式。然而,氯化消毒过程中可产生对健康有害的物质一消毒副产物(disinfection byproducs,DBPs)。消毒副产物主要包括三卤甲烷(trihalomethanes,THMs)、卤代乙酸(haloacefic acids,HAAs)、卤代乙腈(haloaceton itriles,HAN)等。毒理学研究显示DBPs具有遗传毒性、致突变性、细胞毒性、生殖发育毒性和致癌性。膀胱癌是指发生在膀胱黏膜上的恶性肿瘤。是泌尿系统最常见的恶性肿瘤,也是全身十大常见肿瘤之一。有研究表明消化副产物的暴露与膀胱癌     

饮用水氯化消毒副产物与不良生殖结局关系的研究进展

饮用水氯化消毒副产物(chlorination disinfection by-products,DBPs)是在饮用水加氯消毒过程中含氯消毒剂与水中有机物、腐殖酸、富里酸、溴化物及碘化物反应生成的系列化学物[1].现已发现的600余种DBPs中以三卤甲烷类(trihalomethanes,THMs)和卤代乙酸类(haloacetic acids,HAAs)含量最高[2].     

饮水中氯化消毒副产物的控制

氯化消毒是目前国内外广泛采用的饮用水消毒方法。由于氯化消毒的操作简单，便于控制，经济有效，所以在公共给水系统中，加氯消毒已成为最经济有效和应用最广泛的消毒工艺。然而，氯作为饮水消毒剂，会与水中存在的腐殖质(如黄腐酸、腐殖酸)等有机物质发生反应，生成以卤代有机物为代表的消毒副产物(Disinfection by-products，DBPs)，氯消毒的安全问题逐渐引起了人们的重视，控制DBPs的研究也日益深入。     

消毒副产物暴露对男性生殖健康影响的研究进展

消毒副产物(disinfection by-products,DBPs)是饮用水中一类广泛存在的污染物,其来源于饮用水消毒过程中消毒剂与源水中存在的有机或者无机化学物质发生的化学反应。目前在饮用水中已鉴定的DBPs多达600多种,其中三卤甲烷类(trihalomethanes,THMs)和卤代乙酸类(haloacetic acids,HAAs)的含量最高。自20世纪70年代美国国立癌症研究所发现DBPs具有致癌性以来,有关DBPs的潜在健康危害便引起了世界各国的广泛关注,其中DBPs的生殖毒性也成为关注点之一。本文从毒理学和流行病学两方面综述了DBPs暴露对男性生殖健康影响的研究进展,并对其今后的研究展望进行了相关讨论。     

佛山市生活饮用水中氯化消毒副产物监测结果分析

目的 调查佛山市生活饮用水中消毒副产物(DBPs)三卤甲烷(THMs)和卤乙酸(HAAs)的污染现状.方法 采用GC-6890气相色谱仪、ECD检测器、余氯比色计对佛山市26家自来水厂出厂水中的三卤甲烷、卤乙酸、总余氯进行测定.结果 26家自来水厂的出厂水不同程度检出氯化消毒副产物(DBPs)的6种三卤甲烷(THMs)(三氯甲烷、四氯化碳、三氯乙烯、二氯一溴甲烷、一氯二溴甲烷和四氯乙烯)和3种卤乙酸(HAAs)(二氯乙酸、三氯乙酸和余氯),除1家水厂的四氯化碳指标超出国家标准之外,其余指标均符合国家标准.出厂水均未检出三溴甲烷.结论 水中自由余氯是卤代烃含量的影响因素,加大氯含量消毒会产生较多消毒副产物.     

氯化消毒饮用水副产物DBPs对健康的影响

用氯气消毒饮用水,会产生副产物,此类副产物对人体健康会造成极大的影响。该文介绍了饮用水消毒副产物的形成机制、影响饮用水消毒副产物的形成的因素及氯化消毒副产物（DBPs）对健康的影响,以及氯化消毒副产物的毒理及形成的消毒副产物相对较少的其他各种消毒剂。     

氯化消毒过程中卤乙酸形成条件初探

目的：探讨饮用水在氯化消毒过程中腐殖酸与生成卤乙酸之间的关系。方法：以柱前衍生-气相色谱法为检测手段。研究氯化条件对卤乙酸生成量的影响。结果：卤乙酸的生成量随温度升高、腐殖酸浓度增加、氯化剂用量增大和pH值降低而增加。结论：腐殖酸是饮用水氯化消毒副产物的重要前体物质。适当控制氯化条件，可减少消毒过程中卤乙酸的产生。     

国内饮用水中消毒副产物分布水平与健康风险评价

目的了解我国城市饮用水消毒副产物的分布水平及健康风险,为饮水安全管理提供参考。方法通过系统检索2009—2019年公开发表的文献,提取有效数据科学统计国内饮用水消毒副产物的暴露水平,运用EPA推荐的健康风险评价模型对THMs和HAAs两类消毒副产物进行风险评价。结果各类消毒副产物含量水平大小为三卤甲烷卤代乙酸卤乙腈水合氯醛卤代酮类亚硝胺类;南方地区饮用水主要消毒副产物生成量高于北方地区;液氯消毒生成的消毒副产物总量高于其它消毒方式。结论国内城市饮用水各类消毒副产物致癌风险值均大于EPA可接受水平(1×10~(-6));次氯酸钠消毒代替液氯消毒能有效降低消毒副产物对人体的健康风险;儿童的健康风险值大于成人,应重点考虑儿童暴露于水中污染物质的健康风险。     

饮用水消毒中二氧化氯的应用研究

氯消毒剂作为饮用水消毒剂,由于其价格低廉,消毒可靠,经验成熟等诸多优越之处被大力推广及广泛应用。在上个世纪70年代,饮用水氯化消毒副产物逐步被人类认为对人体有毒副作用。Rook、Ames等学者通过大量的生物实验研究证明,水源经过氯化消毒后,其副产物三卤甲烷(THMs)和     

Chlorination disinfection byproducts in water and their association with adverse reproductive outcomes: a review

OBJECTIVES AND METHODS—Chlorination has been the major disinfectant process for domestic drinking water for many years. Concern about the potential health effects of the byproducts of chlorination has prompted the investigation of the possible association between exposure to these byproducts and incidence of human cancer, and more recently, with adverse reproductive outcomes. This paper evaluates both the toxicological and epidemiological data involving chlorination disinfection byproducts (DBPs) and adverse reproductive outcomes, and makes recommendations for future research.
RESULTS AND CONCLUSIONS—Relatively few toxicological and epidemiological studies have been carried out examining the effects of DBPs on reproductive health outcomes. The main outcomes of interest so far have been low birth weight, preterm delivery, spontaneous abortions, stillbirth, and birth defects— in particular central nervous system, major cardiac defects, oral cleft, and respiratory, and neural tube defects. Various toxicological and epidemiological studies point towards an association between trihalomethanes (THMs), one of the main DBPs and marker for total DBP load, and (low) birth weight, although the evidence is not conclusive. Administered doses in toxicological studies have been high and even though epidemiological studies have mostly shown excess risks, these were often not significant and the assessment of exposure was often limited. Some studies have shown associations for DBPs and other outcomes such as spontaneous abortions, stillbirth and birth defects, and although the evidence for these associations is weaker it is gaining weight. There is no evidence for an association between THMs and preterm delivery. The main limitation of most studies so far has been the relatively crude methodology, in particular for assessment of exposure.
RECOMMENDATIONS—Large, well designed epidemiological studies focusing on well defined end points taking into account relevant confounders and with particular emphasis on exposure characterisation are ideally needed to confirm or refute these preliminary findings. In practice, these studies may be impracticable, partly due to the cost involved, but this is an issue that can be put right—for example, by use of subsets of the population in the design of exposure models. The studies should also reflect differences of culture and water treatment in different parts of the world. To identify the specific components that may be of aetiological concern and hence to fit the most appropriate exposure model with which to investigate human exposure to chlorinated DBPs, further detailed toxicological assessments of the mixture of byproducts commonly found in drinking water are also needed.


Keywords: disinfection byproducts; chlorination; reproductive health     

Assessment of disinfection by-products in drinking water in Korea.

The main purpose of applying the chlorination process during water treatment is for disinfection. Research results, however, indicate that disinfection byproducts (DBPs) including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), and chloropicrin (CP) can be produced by the chlorination process. Some of these DBPs are known to be potential human carcinogens. This 3-year project is designed to establish a standard analysis procedure for DBPs in drinking water of this country and investigate the distribution and sources of specific DBPs. The occurrence level of DBPs in drinking water was below 50 micrograms/l in most cases. THMs in plant effluent accounted for 60% of all DBPs measured, whereas HAAs accounted for 20%, HANs 12%, HKs 5% and CP 3%. Chloroform was found to be the major THMs compound (77%), followed by bromodichloromethane (BDCM, 18%) and bromoform (BF, 3%). The concentration of DBPs formed in distribution systems increased from those detected in plant effluent. Comparison of humic acid and sewage as precursors for THMs formation showed that humic acid was the major THMs precursor. Results would play an important role in exposure assessment as a part of the risk assessment process, and would give basic information for establishment of DBPs reduction and management procedures.     

Epidemiological approaches in the investigation of environmental causes of cancer: the case of dioxins and water disinfection by-products

I will refer in this paper to difficulties in research in environmental causes of cancer using as examples research on dioxins and on drinking water disinfection by-products (DBPs) that have created considerable controversy in the scientific and wider community. Dioxins are highly toxic chemicals that are animal carcinogens. For many years, evaluation of the carcinogenicity of dioxins in humans was based on case-control or registry based studies. The development of methods to measure dioxins in blood indicated that these studies suffered from extreme exposure misclassification. The conduct of large cohort studies of workers with widely contrasted exposures together with the use of biomarkers and models for exposure assessment, led to convincing evidence on the carcinogenicity of dioxins in humans. The high toxicity of a few dioxin congeners, the availability of a scheme to characterize the toxicity of a mixture of dioxins and related compounds and the long half-life of these compounds facilitated epidemiological research. Contrary to dioxins, trihalomethanes (THMs) and most of the hundreds of DBPs in drinking water are chemicals of low toxicity. For more than 15 years, the main evidence on the carcinogenicity of DBPs was through ecological or death certificate studies. More recent studies based on individual assessment confirmed increases in bladder cancer risk. However even those studies ignored the toxicological evidence on the importance of routes of exposure to DBPs other than ingestion and, probably, underestimated the risk. Persistence of weak study designs together with delays in advanced exposure assessment models led to delays in confirming early evidence on the carcinogenicity of DBPs. The evaluation of only a few chemicals when exposure is to a complex mixture remains a major problem in exposure assessment for DBPs. The success of epidemiological studies in identifying increased risks lies primarily on the wide contrast of exposure to DBPs in the general population that overcomes the significant exposure misclassification. Exposure assessment has been the Achilles heel for studies on dioxins and DBPs and cancer. The combination of powerful study designs, advanced exposure assessment together with a better understanding of mechanisms of disease and the use of biomarkers of exposure, led to the strengthening of the epidemiological evidence.     

Dermal uptake of chloroform and haloketones during bathing

Dermal contact with some organic disinfection by-products (DBPs) such as trihalomethanes in chlorinated drinking water has been established to be an important exposure route. We evaluated dermal absorption of two haloketones (1,1-dichloropropanone and 1,1,1-trichloropropanone) and chloroform while bathing, by collecting and analyzing time profiles of expired breath samples of six human subjects during and following a 30-min bath. The DBP concentrations in breath increased towards a maximum concentration during bathing. The maximum haloketone breath concentration during dermal exposure ranged from 0.1 to 0.9 microg / m(3), which was approximately two orders of magnitude lower than the maximum chloroform breath concentration during exposure. Based on a one-compartment model, the in vivo permeability of chloroform, 1,1-dichloropropanone, and 1,1,1-trichloropropanone were approximated to be 0.015, 7.5 x 10(- 4), and 4.5 x 10(- 4) cm / h, respectively. Thus, haloketones are much less permeable across human skin under normal bathing conditions than is chloroform. These findings will be useful for future assessment of total human exposure and consequent health risk of these DBPs.     

Water disinfection by-products and bladder cancer: is there a European specificity? A pooled and meta-analysis of European case-control studies

Several epidemiological studies suggested an association between the risk of bladder cancer and the exposure to trihalomethanes (THMs), the main disinfection by-products (DBPs) of chlorinated water. A previous pooled analysis of case-control studies from North America and Europe estimated a summarized dose-response relation. For policy guidance of drinking water disinfection in Europe and because major differences exist in water disinfection practices and DBPs occurrence between both continents, specific risk estimates for bladder cancer in relation to DBPs exposure for European populations were needed. We conducted a pooled and a two-stage random-effect meta-analyses of three European case-control studies from France, Finland, and Spain (5467 individuals: 2381 cases and 3086 controls). Individual exposure to THMs was calculated combining information on residential history, estimates of the average total THMs (TTHM) level in tap water at the successive residences and personal water consumption. A significant odds-ratio was observed for men exposed to an average residential TTHM level > 50 μg/l (OR = 1.47 (1.05; 2.05)) when compared to men exposed to levels ≤ 5 μg/l. The linear trend of the exposure-risk association was significant (p = 0.01). Risks increased significantly for exposure levels above 25 μg/l and with more than 30 years of exposure to chlorinated water, but were mainly driven by the level rather than the duration of exposure. No significant association was found among women or with cumulative exposure through ingestion. There was no evidence of a differential exposure-response relation for TTHM and bladder cancer in Europe and North America. Consequently, a global exposure-risk relation based on 4351 cases and 7055 controls is now available.     

Reproductive and developmental effects of disinfection by-products in drinking water.

Recent epidemiologic studies have reported associations between the consumption of chlorinated drinking water and reproductive and developmental effects. Here we review the available epidemiologic data, assess the hazard potential posed by exposure to disinfection by-products, identify critical data gaps, and offer recommendations for further research. The epidemiologic evidence supporting associations between exposure to water disinfection by-products (DBPs) and adverse pregnancy outcomes is sparse, and positive findings should be interpreted cautiously. The methods used during the early stages of research in this area have been diverse. Variability in exposure assessment and endpoints makes it difficult to synthesize or combine the available data. Exposure misclassification and unmeasured confounding may have lead to bias in risk estimation. Future studies of reproductive outcome and exposure to chlorinated water should use improved methods for exposure assessment to 1) assure selection of appropriate exposure markers, 2) assess seasonal and annual fluctuations in DBPs, 3) assess variability within the distribution system, and 4) assess exposure through multiple routes such as bathing and showering, as well as consumption. Population-based studies should be conducted to evaluate male and female fertility, conception delay, growth retardation, and specific birth defects. The reproductive and developmental effects of exposure to DBPs could be efficiently explored in ongoing investigations by incorporating valid exposure markers and relevant questionnaire information. Future studies should make use of naturally occurring variability in the concentrations of DBPs and may incorporate biomarkers of exposure and effect in their design. Epidemiologic investigations should be conducted in parallel with laboratory-based and animal studies in a coordinated, multidisciplinary approach.     

Trihalomethanes and chlorites in finished drinking water in Sardinia (Italy) and possible health effects

A five years monitoring was carried out in central and southern Sardinia (Italy) to assess the levels of two disinfection by-products (DBPs)--total thrialomethanes (TTHMs) and chlorites--in drinking water Between 1997 and 2002, about 1900 drinking water samples were analysed for both of them. The results showed that TTHMs exceeded very often the maximum admissible concentration. Chlorite concentration was found rising in all the distribution networks since the utilization of chlorine dioxide as disinfectant in 1999, exceeding the maximum contaminant level goals suggested by the World Health Organization. These results are relevant for epidemiological studies on health effects from DBPs exposure.     

中国出生缺陷危险因素的Meta分析

[目的]探讨影响中国出生缺陷发生的主要危险因素，为预防决策提供依据。[方法]利用Meta分析的随机效应模型综合分析国内1991-2004年关于出生缺陷发病危险因素的研究文献14篇。累计病例3054例，对照4281例。[结果]单因素分析合并比值比（OR）分别为：母文化程度（0．7301），流产史（3．3768），孕早期服药（2．9642）、接触化学毒物（3．2927）、剧烈呕吐（10．6965）、感染（6．7954）、接触农药（5．9415）、TORCH感染（2．0370）、负性精神刺激（2．1331），父吸烟（2．2480）和饮酒（2．6646）；多因素分析合并。比值比（OR）分别为：母文化程度（0．6545），孕期营养（3．4488），孕早期服药（3．4892）和负性精神刺激（1．6294）。[结论]影响中国出生缺陷发生的主要危险因素为母文化程度，孕期营养，孕早期服药、感染、剧烈呕吐、接触化学毒物，父吸烟和父饮酒等。     

Human respiratory uptake of chloroform and haloketones during showering

Inhalation is an important exposure route for volatile water contaminants, including disinfection by-products (DBPs). A controlled human study was conducted on six subjects to determine the respiratory uptake of haloketones (HKs) and chloroform, a reference compound, during showering. Breath and air concentrations of the DBPs were measured using gas chromatography and electron capture detector during and following the inhalation exposures. A lower percentage of the HKs (10%) is released from shower water to air than that of chloroform (56%) under the experiment conditions due to the lower volatility of the HKs. Breath concentrations of the DBPs were elevated during the inhalation exposure, while breath concentrations decreased rapidly after the exposure. Approximately 85-90% of the inhaled HKs were absorbed, whereas only 70% of the inhaled chloroform was absorbed for the experiment conditions used. The respiratory uptake of the DBPs was estimated using a linear one-compartment model coupled with a plug flow stream model for the shower system. The internal dose of chloroform normalized to its water concentration was approximately four times that of the HKs after a 30-min inhalation exposure. Approximately 0.3-0.4% of the absorbed HKs and 2-9% of the absorbed chloroform were expired through lung excretion after the 30-min exposure. The inhalation exposure from a typical 10-15 min shower contributes significantly to the total dose for chloroform in chlorinated drinking water but only to a moderate extent for HKs.