广州市饮用水中挥发性有机物的研究

饮用水中的挥发性有机化合物（VOCs）来源于水源水受到的环境污染或是在净化消毒工艺处理工程中反应产生的副产物,可对人体健康造成极大的危害。改革开放以来,广州人口和经济得到突飞猛进的发展,也带来了包括饮用水安全在内的诸多严重的社会和环境问题。虽然饮用水中VOCs的研究已经得到越来越多的重视,但是目前对广州市饮用水中挥发性有机物的研究还鲜有报道。本文在广州市中心城区选取15个不同位置的采样点进行了自来水水样采集,并利用吹扫-捕集-气相色谱-质谱（GC-MS）联用系统分析技术测定水中 VOCs 的种类和三卤甲烷的质量浓度。结果表明,广州市中心城区的自来水中VOCs有20种,以三卤甲烷（THMs）和芳香烃类为主,占了所检出的物质总量的78%以上。THMs中四种化合物（氯仿、一溴二氯甲烷、二溴一氯甲烷、溴仿）的检出率达100%,总三卤甲烷的平均质量浓度为46.46μg· L-1,最大值为53.31μg· L-1,最小值39.91μg· L-1。根据2006版国家饮用水标准,四种三卤甲烷质量浓度均低于标准限值,符合标准要求。对市面上一般的瓶装水的研究发现,瓶装水中三卤甲烷的质量浓度非常低,总三卤甲烷平均质量浓度仅为1.47μg·L-1,约是自来水中质量浓度的1/30。为了解温度及煮沸对自来水中 THMs 质量浓度的影响,本研究设计了实验进行探究。结果发现加热至沸腾过程中,THMs质量浓度随温度升高而升高,而沸腾后THMs骤降,煮沸5 min可降低水中约95%的THMs,接近瓶装水中THMs质量浓度。     

Disinfection byproducts in drinking water and regulatory compliance: A critical review

Disinfection by-products (DBPs) are regulated in drinking water in a number of countries. This critical review focuses on the issues associated with DBP regulatory compliance, including methods for DBP analysis, occurrence levels, the regulation comparison among various countries, DBP compliance strategies, and emerging DBPs. The regulation comparison between China and the United States (US) indicated that the DBP regulations in China are more stringent based on the number of regulated compounds and maximum levels. The comparison assessment using the Information Collection Rule (ICR) database indicated that the compliance rate of 500 large US water plants under the China regulations is much lower than that under the US regulations (e.g. 62.2% versus 89.6% for total trihalomethanes). Precursor removal and alternative disinfectants are common practices for DBP regulatory compliance. DBP removal after formation, including air stripping for trihalomethane removal and biodegradation for haloacetic acid removal, have gained more acceptance in DBP control. Formation of emerging DBPs, including iodinated DBPs and nitrogenous DBPs, is one of unintended consequences of precursor removal and alternative disinfection. At much lower levels than carbonaceous DBPs, however, emerging DBPs have posed higher health risks.     

饮用水细菌内毒素污染的风险识别与分析研究进展

细菌内毒素,又称脂多糖分子或者热原,是革兰氏阴性细菌和某些蓝藻细胞壁组分,主要由菌体死亡解体后释放.内毒素是常见的外源性致热原,属于强免疫刺激剂,与多种人类疾病密切相关.由于饮用水中会滋长微生物,因此内毒素污染在饮用水中普遍存在.近年来,国外研究中饮用水的细菌内毒素污染开始受到关注,成为饮用水微生物安全领域新兴的研究方向.本文概述了细菌内毒素的物化性质和生物活性,分析了细菌内毒素在饮用水中的存在形态,综述了国内外关于地表水源、地下水源、管网末梢水和深度处理水的内毒素污染调查状况,分析了传统水处理技术、深度处理技术和饮用水消毒技术对内毒素的控制效果,探讨了饮用水中内毒素的血液暴露、呼吸暴露和胃肠暴露途径导致机体潜在的健康风险、安全阈值和相关标准,并对饮用水细菌内毒素污染研究方向进行了展望.     

上海市松江镇饮用水水源区的保护与环境管理方案

保护集镇饮用水河流是当前水污染防治工作的重点。本文通过现状分析，针对城乡结合部河流以面源为主的特点，找出影响饮用水河流水质的主要污染源及污水排放特征．用系统分析方法，将集镇的经济、人口、环境统计资料作为环境管理模型的主要输入信息，经计算机仿真，得出保护水源水质应采取的对策与治理方案。     

An exploratory study of chemical elements in drinking water and non-Hodgkin's lymphoma

Nanomaterials are widely used in the field of engineering and in modern society. Although the unique characteristics of nanoparticles also enable them to provide environmental solutions to reduce the formation and emissions of pollutants, adverse effects on human health may occur from the exposure to nanomaterials during the manufacturing processes and when nanomaterials are released and they contaminate the environment. It is essential to understand the factors affecting the accumulation, aggregation, deposition, translocation, and distribution of nanomaterials (natural or engineered) in the ecosystem. This study presents an extensive review of the environmental effects of nanomaterials, including classification, adverse impacts on human health and the environment, transport pathways, monitoring methods, and the current regulations regarding nanomaterials. The review indicates that the diversity of nanoparticles and their properties make the identification and characterization of nanomaterials a difficult task, and an improvement in sensitivity and selectivity of analytical methods for detecting nanoparticles in the environment is required. Besides, few regulations have been established for the management of nanoparticles released into the environment. In order to expedite the environmental management of nanomaterials, this study proposes a risk assessment framework based on the findings in the review as a practice alternative for the environmental assessment and effective management of nanomaterials. Development of practical innovative risk-based management measures may help us to find answers to the concerns such as safety of engineering and applying nanomaterials and effective control of nanoparticle contamination in the environment.     

管网生物膜菌株胞外聚合物的提取方法比较

以饮用水管网生物膜样品中一株强成膜能力的菌株Pleomorphomonas oryzae作为研究对象,考察了8种方法(高速离心法、超声法、加热法、EDTA法、H2SO4法、NaOH法、SDS法、甲醛法)对菌株胞外聚合物(EPS)的提取效果,并结合三维荧光光谱(EEM)和傅立叶红外光谱(FTIR)对提取的EPS进行成分分析.结果表明,EDTA法和H2SO4法既能提高EPS的提取效率,提取量分别为64.77 mg.g-1SS和74.43 mg.g-1SS,是离心方法提取量的1.62倍和1.86倍,又不会在提取过程中对菌株细胞造成破坏,是较为理想的EPS提取方法.EEM分析进一步证实,NaOH法对菌株细胞破坏严重,造成EPS成分变化较大.FTIR分析则说明,化学提取方法相较于物理提取方法会引入杂质对组分测定造成干扰.     

饮用水有机类消毒副产物毒理学研究方法进展

伴随着饮用水消毒技术的改进,有机类消毒副产物(DBPs)的种类日趋多样化,其生物毒性和健康风险受到广泛关注。基于国内外对DBPs毒理学效应的研究成果,结合消毒技术的发展历程,对有机类DBPs进行了系统的分类,针对含碳消毒副产物(C-DBPs)和含氮消毒副产物(N-DBPs)中典型的DBPs的毒理学研究方法进行了详细的介绍,在此基础上分析了相关研究的不足之处和发展趋势,对今后的研究方向提出了建议。     

Effects of humic acid on residual Al control in drinking water treatment plants with orthophosphate addition

This study aimed to investigate the effects of humic acid (HA) on residual Al control in drinking water facilities that used orthophosphate addition. The results showed that adding orthophosphate was an effective method for residual Al control for the raw water without HA. When orthophosphate was added at 1.0 min before the addition of poly aluminum chloride (PACl), the concentrations of soluble aluminum (Sol-Al) and total aluminum (Tot-Al) residue were 0.08 and 0.086 mg·L^-1, respectively; both were reduced by 46% compared with the control experiment. The presence of HA would notably increase the residual Al concentration. For the raw water with 5 mg·L^-1 of HA, the concentrations of Sol-Al and Tot-Al increased from 0.136 and 0.174 mg·L^-1 to 0.172 and 0.272 mg·L^-1, respectively. For water with a HA concentration above 5 mg·L^-1, orthophosphate was ineffective in the control of residual Al, though there were still parts of orthophosphate were removed in coagulation. The amounts of Al removal were positively correlated with the solids freshly formed in coagulation. Similar to the raw water without HA, the best Al control was obtained with orthophosphate salt added at 1.0 min before PACl. HA concentrations in the raw water, solution pH, and the orthophosphate dosage suitable for residual Al control by orthophosphate precipitation were also investigated.     

Presence of metals in drinking water distribution networks due to pipe material leaching: a review

Drinking water quality should remain constant from the drinking water treatment plant to the consumer's tap. However, water quality characteristics might be affected by interactions with pipe materials. This review describes the iron, copper, lead, zinc, aluminum, chromium, and cadmium in drinking water leached from the pipe material present in drinking water, as well as the factors and mechanisms that affect leaching processes. Data analysis suggests that monitoring the water quality in distribution systems is important for their proper management; however, the low measured concentrations highlight the need for sensitive sensors. In addition, further research is necessary to anticipate possible future effects before the installation of new materials/infrastructure or changes in water source/treatment.     

Applying chemical sedimentation process in drinking water treatment plant to address the emergent arsenic spills in water sources

Arsenic (As) spills occurred more frequently and sometimes polluted water sources in recent years in China. It is as urgent need to develop emergency treatment technologies to address the arsenic threat for large-scale water treatment plants. In response, we developed a chemical sedimentation technology to remove arsenic contaminants for water treatment plants. Bench-scale experiments were conducted to investigate the efficiency of arsenic removal and the influencing factors of the chemical sedimentation treatment process. The influencing factors included the choice and dosage of coagulants, the valence of arsenic and pH value of solution. The As(V) contaminants can be almost completely removed by ferric or alum coagulants. The As(III) contaminants are more recalcitrant to chemical sedimentation, 75% for ferric coagulant and 40% for alum coagulant. The quantitative results of arsenic removal load by different ferric or alum coagulants were presented to help determine the parameters for arsenic treatment technology. The dominant mechanism for arsenic removal is static combination, or adsorption of negative arsenic species onto positive ferric hydroxide or alum hydroxide flocs. The efficiency of this treatment technology has also been demonstrated by a real production test in one water treatment plant with arsenic-rich source water and one emergency response. This technology was verified to be quick to set-up, easy to operate and highly efficient even for high concentration of arsenic.     

Synergistic effects of sodium hypochlorite disinfection and iron-oxidizing bacteria on early corrosion in cast iron pipes

• The early corrosion process in the cast iron pipes was investigated. • The increase of NaOCl (<0.75 mg/L) accelerated the cast iron corrosion. • Biocorrosion caused by IOB could be divided into three stages in the early stage. • Synergistic and antagonistic effects exist between residual chlorine and IOB. Corrosion in drinking water distribution systems (DWDSs) may lead to pipe failures and water quality deterioration; biocorrosion is the most common type. Chlorine disinfectants are widely used in DWDSs to inhibit microorganism growth, but these also promote electrochemical corrosion to a certain extent. This study explored the independent and synergistic effects of chlorine and microorganisms on pipeline corrosion. Sodium hypochlorite (NaOCl) at different concentrations (0, 0.25, 0.50, and 0.75 mg/L) and iron-oxidizing bacteria (IOB) were added to the reaction system, and a biofilm annular reactor (BAR) was employed to simulate operational water supply pipes and explain the composite effects. The degree of corrosion became severe with increasing NaOCl dosage. IOB accelerated the corrosion rate at an early stage, after which the reaction system gradually stabilized. When NaOCl and IOB existed together in the BAR, both synergistic and antagonistic effects occurred during the corrosion process. The AOC content increased due to the addition of NaOCl, which is conducive to bacterial regrowth. However, biofilm on cast iron coupons was greatly influenced by the disinfectant, leading to a decrease in microbial biomass over time. More research is needed to provide guidelines for pipeline corrosion control.     

Urinary arsenic methylation profile in children exposed to low arsenic levels through drinking water

There is a lack of information on arsenic metabolism in children exposed chronically to low levels of arsenic (<50 µg L^?1). The objective of this study was to determine the methylation profile of urinary arsenic metabolites in children exposed to low-level concentrations of arsenic via their drinking water. A cross-sectional study was undertaken in 50 children from four towns in the Yaqui Valley, Sonora, with total arsenic values of 39.9, 16.8, 7.3, and 5.5 µg L^?1 in their drinking water, respectively. First morning void samples were analyzed for inorganic-As (InAs), mono and dimethyl arsenic (MMA and DMA). The total arsenic excreted in urine ranged from 23.1 to 99.1 µg L^?1 and these levels did not vary by sex. Children with the highest level of total arsenic in their drinking water excreted the highest amount in urine and the length of residence and age also had significant contribution. Children with a lower range of arsenic exposure (16.8–5.5 µg L^?1) had similar amounts of arsenic in urine with values of 23.1, 28.2, and 32.6 µg L^?1, respectively. DMA had the highest proportion in urine (52.1–74.7%), followed by InAs (16.3–34.9%) and MMA (4.4–8.4%). Compared to other reports, these children excreted a low %MMA (6.1%), and children from the towns with the lowest levels of arsenic had the highest %InAs and the lowest %DMA. This variability in arsenic methylation was partially explained by arsenic concentration in drinking water, years of residence and age, and may reflect genetic differences or more contribution from different exposure routes. In conclusion, our results show that at low levels of exposure the children's ability to metabolize InAs did not have a linear association with the levels of arsenic, and overall children from the Yaqui Valley excrete a lower %MMA than expected.     

A red water occurrence in drinking water distribution systems caused by changes in water source in Beijing,China: mechanism analysis and control measures

A red water phenomenon occurred in several communities few days after the change of water source in Beijing, China in 2008. In this study, the origin of this problem, the mechanism of iron release and various control measures were investigated. The results indicated that a significant increase in sulphate concentration as a result of the new water source was the cause of the red water phenomenon. The mechanism of iron release was found that the high-concentration sulphate in the new water source disrupted the stable shell of scale on the inner pipe and led to the release of iron compounds. Experiments showed that the iron release rate in the new source water within pipe section was over 11-fold higher than that occurring within the local source water. The recovery of tap water quality lasted several months despite ameliora- tive measures being implemented, including adding phosphate, reducing the overall proportion of the new water source, elevating the pH and alkalinity, and utilizing free chlorine as a disinfectant instead of chloramine. Adding phosphate was more effective and more practical than the other measures. The iron release rate was decreased after the addition of 1.5 mg. L-1 orthophosphate- P, tripolyphosphate-P and hexametaphosphate-P by 68%, 83% and 87%, respectively. Elevating the pH and alkalinity also reduced the iron release rate by 50%. However, the iron release rate did not decreased after replacing chloramine by 0.5-0.8 mg. L-1 of free chlorine as disinfectant.     

Life cycle assessment and environmental improvement of residential and drinking water supply systems in Hanoi,Vietnam

In many Asian cities the public water supply is characterised by low pressure, frequent interruptions and occasional contamination. Hence, private households have to store water and increase pressure individually to ensure an uninterrupted supply at sufficient pressure and water for drinking has to be boiled or supplied separately in bottles. In this study the present water supply system in Hanoi and a number of modification options were analysed from an environmental point of view through life cycle assessment (LCA) in order to identify the most sustainable solutions for future water supply. It was found that the boiling of water for drinking was the largest source of impacts in the present system. Impacts could be reduced significantly if the public supply network was improved and private pumping and storage could be avoided and if the water could be used directly for drinking. It was also found that impacts could be reduced if consumers used bottled water for drinking instead of boiling tap water. Finally, it was demonstrated that even if drinking water cannot be supplied directly through the public network, a reliable public water supply at high pressure is environmentally advantageous. Sensitivity analyses revealed that the conclusions of this study are likely to be applicable to other cities with similar water supply systems.     

Biofiltration and disinfection codetermine the bacterial antibiotic resistome in drinking water: A review and meta-analysis

• Published data was used to analyze the fate of ARGs in water treatment. • Biomass removal leads to the reduction in absolute abundance of ARGs. • Mechanism that filter biofilm maintain ARB/ARGs was summarized. • Potential BAR risks caused by biofiltration and chlorination were proposed. The bacterial antibiotic resistome (BAR) is one of the most serious contemporary medical challenges. The BAR problem in drinking water is receiving growing attention. In this study, we focused on the distribution, changes, and health risks of the BAR throughout the drinking water treatment system. We extracted the antibiotic resistance gene (ARG) data from recent publications and analyzed ARG profiles based on diversity, absolute abundance, and relative abundance. The absolute abundance of ARG was found to decrease with water treatment processes and was positively correlated with the abundance of 16S rRNA (r² = 0.963, p<0.001), indicating that the reduction of ARG concentration was accompanied by decreasing biomass. Among treatment processes, biofiltration and chlorination were discovered to play important roles in shaping the bacterial antibiotic resistome. Chlorination exhibited positive effects in controlling the diversity of ARG, while biofiltration, especially granular activated carbon filtration, increased the diversity of ARG. Both biofiltration and chlorination altered the structure of the resistome by affecting relative ARG abundance. In addition, we analyzed the mechanism behind the impact of biofiltration and chlorination on the bacterial antibiotic resistome. By intercepting influent ARG-carrying bacteria, biofilters can enrich various ARGs and maintain ARGs in biofilm. Chlorination further selects bacteria co-resistant to chlorine and antibiotics. Finally, we proposed the BAR health risks caused by biofiltration and chlorination in water treatment. To reduce potential BAR risk in drinking water, membrane filtration technology and water boiling are recommended at the point of use.     

新型含氮消毒副产物的生成机制及毒性研究进展

含氮消毒副产物(N-DBPs)具有很高的生物毒性和致癌性,近年来受到广泛关注。本文对目前N-DBPs的研究进展进行了概述,重点总结了典型N-DBPs包括卤乙腈(HANs)、卤代硝基甲烷(HNMs)、卤代乙酰胺(HAcAms)和亚硝胺(NAs)的生成机制;并归纳了N-DBPs的毒性效应和毒性机制。根据N-DBPs的生成途径,应该重点控制水中含胺类氮源前体物,并优化设计消毒剂种类和投加方式,在控制病原体的前提下,尽量削减高毒性N-DBPs的生成。本研究旨在为控制消毒副产物生成、提高饮用水水质提供理论参考。     

Occurrence of odor problems in drinking water of major cities across China

A comprehensive investigation into the occur-rence of odor problem at 111 drinking water treatment plants （DWTPs） in major cities across China was undertaken using both flavor profile analysis （FPA） and gas chromatography-mass spectrometry （GC-MS）. Eighty percent of source water samples exhibited odor problems, characterized by earthy/musty （41%） and swampy/septic （36%） odors, while the occurrence rate was lower （45%） in the finished water. Source water from rivers exhibited more pollution-origin odors, such as the swampy/septic odor, while that from lakes and reservoirs exhibited more algae- origin odors, such as earthy/musty odors. The occurrence rate of 2-methylisoborneol （2-MIB） in the surface source water samples was 75%, with 7% of samples containing 2- MIB concentrations of over 10 ng.L-1. The earthy/musty odor in the lake/reservoir water samples was mainly caused by 2-MIB （linear regression coefficient, R2= 0.69）, while the correlation between 2-MIB concentration and the earthy/musty odor intensity samples was weak （R2= 0.35） in the river-source water These results will be useful for the management of odor-quality problems in drinking water of China.     

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinking water distribution system

Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters. The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination. The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors (RAB) with different chlorine to ammonia ratios and total organic carbon (TOC) levels. The results indicated that nitrification occurred despite at a low influent concentration of ammonia, and a high concentration of nitrite nitrogen was detected in the effluent. The study illustrated that reactors 1(R1) and 3 (R3), with higher TOC levels, produced more nitrite nitrogen, which was consistent with the ammonia-oxidizing bacteria (AOB) counts, and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts (R2 and R4). The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification. Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors. The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification. Bulk water with a high TOC level supported the occurrence of nitrification, and AOB development occurred at all examined chlorine to ammonia dose ratios (3:1 or 5:1).     

广东西江流域饮用水源中典型持久性有机污染物的含量与来源

从广东省西江流域三个饮用水源地采集三个样品,分别分析其中两类持久性有机污染物—有机氯农药和多环芳烃的含量以及来源,从这两类污染物对水环境污染的角度初步判断饮用水源的安全性。首先采用液液萃取的方法对样品进行前处理,然后分别用GC．ECD和GC—MS测定有机氯农药和多环芳烃的含量。实验发现有机氯农药质量浓度在水相中为1．99ng·L^-1～ 4．76ng·L^-1,在颗粒相中为0．36ng·L^-1～0．68ng·L^-1;多环芳烃质量浓度在水相中为73．40ng·L^-1～865．89ng·L^-1,在颗粒相中为16．76ng·L^-1～19．31ng·L^-1。结果表明,六六六和滴滴涕质量浓度低于国标《生活饮用水水源水质标准》（CJ3020．93）的规定,同时苯并[a]芘也低于世界卫生组织《饮用水水质标准》的规定,而其它物质标准中均无规定。由此说明,就有机氯农药和多环芳烃这两类污染物在水中的含量来说,广东西江领域饮用水源是相对安全的。但是由于这两类污染物都具有很强的生物富集性,因此它们在水环境中的存在和作用也是不容忽视的。     

Treatment,residual chlorine and season as factors affecting variability of trihalomethanes in small drinking water systems

Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate seasonal variability of water quality in municipal small water systems (<3000 residents) supplied by surface waters. Residual chlorine and trihalomethanes (THM) were measured over seven years (2003–2009). Comparisons are made within each system over time, as well as between systems according to the type of their treatment technologies. THM concentrations are generally higher in the summer and autumn. The seasonal variability was generally more pronounced in systems using chlorination plus additional treatment. Chloroform, total THM (TTHM) and residual chlorine concentrations were generally lower in systems using chlorination plus additional treatment. Conversely, brominated THM concentrations were higher in systems using additional treatment. Residual chlorine was highest in the winter and lowest in the spring and summer. Seasonal variations were most pronounced for residual chlorine in systems with additional treatment. There was generally poor correlation between THM concentrations and concentrations of residual chlorine. Further study with these data will be beneficial in finding determinants and indicators for both quantity and variability of disinfection byproducts and other water quality parameters.