PUMPS,GERMS AND STORAGE: THE IMPACT OF IMPROVED WATER CONTAINERS ON WATER QUALITY AND HEALTH

Applying a randomized controlled trial, we study the impact of improved water transport and storage containers on the water quality and health of poor rural households. The results indicate that improved household water infrastructure improves water quality and health outcomes in an environment where point‐of‐source water quality is good but where recontamination is widespread, leading to unsafe point‐of‐use drinking water. Moreover, usage rates of 88% after 7 months are encouraging with regard to sustainable adoption. Our estimates suggest that the provision of improved household water infrastructure could ‘keep clean water clean’ at a cost of only 5% of the costs of providing households with improved public water supply. Given the general consensus in the literature that recontamination of water from improved public sources is a severe public health problem, improved transport and storage technologies appear to be an effective low‐cost supplement to the current standard of financing public water supply for poor rural communities. Copyright © 2012 John Wiley & Sons, Ltd.     

广东省管道直饮水系统水质变化趋势分析

目的了解广东省管道直饮水系统的水质现状和变化趋势。方法于2004-2008年,选择广东省不同地区、不同类型的管道直饮水系统进行重金属、有机物、微生物等指标的净化效果和变化趋势分析。结果市政自来水经过净化后(直饮水)其硝酸盐、砷、氯仿、四氯化碳的去除率未达到《生活饮用水水质处理器卫生安全与功能评价规范-反渗透处理装置》(2001)的要求,耗氧量(82.55%)等指标去除率达到要求,反渗透膜脱盐率只有71.4%符合GB/T19249-2003的要求。微生物、重金属、电导率等指标在研究期间无明显变化(P0.05),而耗氧量从0.45mg/L上升至1.18 mg/L(P0.01);浊度每月变化差异有统计学意义(P0.01),最高值为0.55 NTU,最低值为0.11NTU。不同直饮水系统的电导率、pH等特异水质指标间差异有统计学意义(P0.01);反渗透设备脱盐率最高为99.1%,最低为90.7%。广州、深圳、珠海、东莞市直饮水的溶解性总固体均值分别为13.3,76.6,37.9,20.6 mg/L,差异有统计学意义(P0.01)。结论不同地区和不同类型管道直饮水系统水质各不相同,耗氧量有增加趋势;浊度有变化,微生物和重金属没有变化。     

管道直饮水项目的卫生现状与评价

目的 调查深圳市管道直饮水卫生现状,为制订直饮水卫生规范提供依据。方法 对本市15个管道直饮水项目选址、功能间布局、工艺、水处理设备及卫生设施进行卫生工程学分析,抽取15份成品水样进行水质检测。结果 2个管道直饮水项目选址、5个项目功能间布局、2个项目水处理设备不符合卫生要求;2份水样细菌总数含量超标。结论 本市管道直饮水项目仍存在卫生学问题,必须加强卫生管理。     

Following the Water: A Controlled Study of Drinking Water Storage in Northern Coastal Ecuador

Background

To design the most appropriate interventions to improve water quality and supply, information is needed to assess water contamination in a variety of community settings, including those that rely primarily on unimproved surface sources of drinking water.

Objectives

We explored the role of initial source water conditions as well as household factors in determining household water quality, and how levels of contamination of drinking water change over time, in a rural setting in northern coastal Ecuador.

Methods

We sampled source waters concurrently with water collection by household members and followed this water over time, comparing Escherichia coli and enterococci concentrations in water stored in households with water stored under controlled conditions.

Results

We observed significant natural attenuation of indicator organisms in control containers and significant, although less pronounced, reductions of indicators between the source of drinking water and its point of use through the third day of sampling. These reductions were followed by recontamination in approximately half of the households.

Conclusions

Water quality improved after water was transferred from the source to household storage containers, but then declined because of recontamination in the home. Our experimental design allowed us to observe these dynamics by controlling for initial source water quality and following changes in water quality over time. These data, because of our controlled experimental design, may explain why recontamination has been reported in the literature as less prominent in areas or households with highly contaminated source waters. Our results also suggest that efforts to improve source water quality and sanitation remain important.     

移动式消毒车在血透供水管路消毒中的应用

本文介绍了一种移动式消毒车,就其在血液透析室水处理系统中对供水管路进行消毒的实际应用情况和消毒效果进行了分析。     

北京市住宅小区管道直饮水设备水质卫生学调查

[目的]了解目前北京地区管道直饮水设备卫生状况。[方法]随机选取北京地区14家使用管道直饮水设备的住宅小区,检测自来水(原水),设备出水和远端末梢水样。[结果]9个安装净水设备的住宅小区,有3个小区的pH值不合格,1个小区浑浊度超标,2个小区检出霉菌和酵母菌。5个使用纯水设备的小区各样品检测指标均符合相关标准。[结论]北京地区目前使用的管道直饮水卫生状况基本良好,但管网存在二次污染的可能性。     

2011年肇庆市管道直饮水的卫生现状调查

目的了解2011年肇庆市管道直饮水卫生状况,为制定提高肇庆市直饮水卫生质量的措施提供科学依据。方法采用随机抽样的方法,监测120份市政自来水与管道直饮水配对样本。结果肇庆市120份市政自来水水样与管道直饮水水样的检测项目中pH值(pH=6.63)、总硬度(38 mg/L)和细菌总数(18 CFU/ml)的差异有统计学意义(P0.01),直饮水的pH值、总硬度明显低于市政自来水,但直饮水细菌总数的超标率明显比自来水高,其他检测指标均无明显的变化(P0.05)。结论肇庆市管道直饮水系统的水质有变化,其中pH值、总硬度降低,细菌总数超标,二次污染现象显著。随着管道直饮水的普及提示有关部门必须规范及调整饮用净水水质卫生标准,不断加强管道直饮水监测卫生管理工作,防止二次污染,以进一步提高管道直饮水的卫生质量。     

透析用水处理设备的配置分析

透析用水处理设备在透析治疗过程中起着关键性的作用,它由预处理、反渗透机、供水管路组成。由于某些厂家的配置和结构不是很科学,故对水处理设备的配置进行分析,对于透析室工程师,甚至是采购的决策者有着重要意义。怎样才能做到科学合理地配置,主要要考虑:选用采用循环供水方式的透析用水处理设备;主机的产水量达到在特定水源温度下满足无菌透析用水量的基本要求;供水管路管径的选取既能满足循环管路最小流量的要求,又能使设备在正常工作压力下工作;预处理系统最好完备,但树脂罐和活性炭罐的容积和充填量以够用为原则;反渗透系统宜采用双级反渗透系统,纯水、浓水的回流位置和级间匹配问题可根据具体需要确定。     

Implementation of a source term control program in a mature boiling water reactor

The implementation and results of a source term control program implemented at the James A. FitzPatrick Nuclear Power Plant (JAF), a mature boiling water reactor (BWR) facility that has been in commercial operation since 1975, are discussed. Following a chemical decontamination of the reactor water recirculation piping in the Reload 8/Cycle 9 refueling outage in 1988, hydrogen water chemistry (HWC) and feedwater Zn addition were implemented. This is the first application of both HWC and feedwater Zn addition in a BWR facility. The radiological benefits and impacts of combined operation of HWC and feedwater Zn addition at JAF during Cycle 9 are detailed and summarized. The implementation of hydrogen water chemistry resulted in a significant transport of corrosion products within the reactor coolant system that was greater than anticipated. Feedwater Zn addition appears to be effective in controlling buildup of other activated corrosion products such as 60Co on reactor water recirculation piping; however, adverse impacts were encountered. The major adverse impact of feedwater Zn addition is the production of 65Zn that is released during plant outages and operational transients.     

Quality of Drinking-water at Source and Point-of-consumption��Drinking Cup As a High Potential Recontamination Risk: A Field Study in Bolivia

In-house contamination of drinking-water is a persistent problem in developing countries. This study aimed at identifying critical points of contamination and determining the extent of recontamination after water treatment. In total, 81 households were visited, and 347 water samples from their current sources of water, transport vessels, treated water, and drinking vessels were analyzed. The quality of water was assessed using Escherichia coli as an indicator for faecal contamination. The concentration of E. coli increased significantly from the water source [median=0 colony-forming unit (CFU)/100 mL, interquartile range (IQR: 0–13)] to the drinking cup (median=8 CFU/100 mL; IQR: 0–550; n=81, z=−3.7, p<0.001). About two-thirds (34/52) of drinking vessels were contaminated with E. coli. Although boiling and solar disinfection of water (SODIS) improved the quality of drinking-water (median=0 CFU/100 mL; IQR: 0–0.05), recontamination at the point-of-consumption significantly reduced the quality of water in the cups (median=8, IQR: 0–500; n=45, z=−2.4, p=0.015). Home-based interventions in disinfection of water may not guarantee health benefits without complementary hygiene education due to the risk of post-treatment contamination.Key words: Disinfection, Drinking-water, Hygiene, Water management, Water pollution, Water supply, Bolivia     

某油田输配水管网生物性腐蚀原因调查

调查了某油田的水源水、电渗析淡水和供水站生活用水中的铁细菌和硫细菌。采用滤膜集菌增菌培养方法。结果表明这3种水中硫细菌的含量随水中溶解氧量的增加而减少;铁细菌的含量则相反,随水中溶解氧的增加而增多。说明生物性厌氧腐蚀以硫细菌为主,好氧腐蚀则以铁细菌为主。分离出10种铁细菌和6种硫细菌,表明铁细菌和硫细菌是导致生活饮用水产生臭气和管道严重锈蚀、堵塞与穿孔的重要原因之一。     

A case report of false negative Legionella test results in a chlorinated public hot water distribution system due to the lack of sodium thiosulfate in sampling bottles

We examined samples from the showers and the central water distribution system of a public building with an indoor swimming pool. The pool was used for school and recreational activities and as a sports therapy facility for patients with coronary heart disease. The building's hot water system was contaminated with Legionella pneumophila. Due to the building's intricate piping system, several attempts to completely eliminate legionellae by thermal and chemical disinfection had failed, so an external sanitation company was charged with the installation of a continuous chlorination device in order to keep Legionella concentrations low. The laboratory which was contracted by the sanitation company to monitor bacteria levels after installation of the chlorination device used sampling bottles without sodium thiosulfate and repeatedly reported an absence of Legionella. However, up to 69,000 colony forming particles (CFP) of Legionella pneumophila (Lp) per litre and up to 171 CFP/ml of heterotrophic bacteria could be detected when parallel samples were collected in bottles containing sodium thiosulfate at standard concentrations. Laboratories, epidemiologists, public health officials and technical staff who may be in charge of delivering, preparing or using sterile sampling devices for the collection of environmental samples to be tested for legionellae should be aware that cultures can return false negative results if the sampling containers used to collect chlorinated drinking water or chlorinated pool water samples do not contain a neutralizing agent to instantly inactivate residual halogen biocides. False negative results may lead to a false sense of security regarding the safety of water systems or the success of disinfection measures, and may thus endanger public health or even hinder the epidemiological clarification of outbreaks.     

湖沼垸内型血吸虫病疫区渠道硬化消灭钉螺的研究

目的 为彻底消灭湖沼垸内钉螺,为控制血吸虫病疫情提供更为有效的灭螺方法和科学依据.方法 采用水泥管道及砖砌两种方法硬化渠道.结果 硬化24条有螺渠道,钉螺面积22.65万m2,灭光钉螺渠道16条,钉螺面积17.81万m2,分别占66.67%、78.63%.水泥管道硬化11条,水泥砖砌硬化13条,水泥管道硬化灭光钉螺渠道9条.水泥砖砌硬化灭光钉螺渠道7条,分别占81.82%、53.85%,灭光钉螺面积分别占 97.88%、55.66%.结论 硬化有螺渠道是一种环保型的有效灭螺方法,水泥管道硬化灭螺效果优于水泥砖砌硬化灭螺.     

Peracetic acid in the disinfection of a hospital water system contaminated with Legionella species.

OBJECTIVE: To assess the efficacy of an alternative disinfection method for hospital water distribution systems contaminated with Legionella. METHODS: Disinfection with peracetic acid was performed in a small hospital contaminated with L. pneumophila serotype 1. The disinfectant was used at concentrations of 50 ppm (first three surveillance phases) and 1,000 ppm (fourth surveillance phase) for 30 minutes. RESULTS: Environmental monitoring revealed that disinfection was maintained 1 week after treatment; however, levels of recontamination surpassing baseline values were detected after approximately 1 month. Comparison of water temperatures measured at the distal outlets showed a statistically significant association between temperature and bacterial load. The circulating water temperature was found to be lower in the two wards farthest away from the hot water production plant than in other wards. It was thought that the lower water temperature in the two wards promoted the bacterial growth even after disinfection. CONCLUSION: Peracetic acid may be useful in emergency situations, but does not provide definitive protection even if used monthly.     

Rapid recontamination with MRSA of the environment of an intensive care unit after decontamination with hydrogen peroxide vapour

Meticillin-resistant Staphylococcus aureus (MRSA) persists in the hospital environment and conventional cleaning procedures do not necessarily eliminate contamination. A prospective study was conducted on an intensive care unit to establish the level of environmental contamination with MRSA, assess the effectiveness of hydrogen peroxide vapour (HPV) decontamination and determine the rate of environmental recontamination. MRSA was isolated from 11.2% of environmental sites in the three months preceding the use of HPV and epidemiological typing revealed that the types circulating within the environment were similar to those colonising patients. After patient discharge and terminal cleaning using conventional methods, MRSA was isolated from five sites (17.2%). After HPV decontamination but before the readmission of patients, MRSA was not isolated from the environment. Twenty-four hours after readmitting patients, including two colonized with MRSA, the organism was isolated from five sites. The strains were indistinguishable from a strain with which a patient was colonized but were not all confined to the immediate vicinity of the colonized patient. In the eight weeks after the use of HPV, the environment was sampled on a weekly basis and MRSA was isolated from 16.3% sites. Hydrogen peroxide vapour is effective in eliminating bacteria from the environment but the rapid rate of recontamination suggests that it is not an effective means of maintaining low levels of environmental contamination in an open-plan intensive care unit.     

试论气动管道物流传输在医院中的应用和改进

气动管道物流传输技术已被越来越多的医院所采用.如何用好管好,提高运送可靠性,作者根据自己在气动管道物流传输系统运行管理中所遇到的问题和多年积累的经验,通过改进系统硬件和不断优化管理,使得该传输系统更适合医院的实际需要.作者希望通过此文,与同行讨论交流.     

Assessing the biological efficacy and rate of recontamination following hydrogen peroxide vapour decontamination

The inanimate hospital environment can become contaminated with nosocomial pathogens. Hydrogen peroxide vapour (HPV) decontamination has proven effective for the eradication of persistent environmental contamination. We investigated the extent of meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and gentamicin-resistant Gram-negative rod (GNR) contamination in a ward side-room occupied by a patient with a history of MRSA, VRE and GNR infection and colonisation and investigated the impact of HPV decontamination. Fifteen standardised sites in the room were sampled using a selective broth enrichment protocol to culture MRSA, VRE and GNR. Sampling was performed before cleaning, after cleaning, after HPV decontamination and at intervals over the subsequent 19 days on two separate occasions. Environmental contamination was identified before cleaning on 60, 30 and 6.7% of sites for MRSA, GNR and VRE, respectively, and 40, 10 and 6.7% of sites after cleaning. Only one site (3.3%) was contaminated with MRSA after HPV decontamination. No recontamination with VRE was identified and no recontamination with MRSA and GNR was identified during the two days following HPV decontamination. Substantial recontamination was identified approximately one week after HPV decontamination towards post-cleaning levels for GNR and towards pre-cleaning levels for MRSA. HPV is more effective than standard terminal cleaning for the eradication of nosocomial pathogens. Recontamination was not immediate for MRSA and GNR but contamination returned within a week in a room occupied by a patient colonised with MRSA and GNR. This finding has important implications for the optimal deployment of HPV decontamination in hospitals.     

The gastrointestinal tract and acute effects of copper in drinking water and beverages

Copper is an essential element for all living beings. Exposure to copper results almost exclusively from the ingestion of food and water. Generally, potable water contains low levels of copper, but high concentrations of this mineral have been found in water from private wells or when water or beverages with low pH have been conducted through copper piping. Some authors have associated acute gastrointestinal symptoms (diarrhea, abdominal pain, nausea, and vomiting) with elevated levels of copper in water or beverages, but without excluding other confounding factors that could produce such symptoms. Recently, various controlled studies have demonstrated that a concentration of 2 mg Cu/L of potable water does not produce an increase in gastrointestinal symptoms in infants, and that in women, only concentrations greater than 3 mg Cu/L increase the number of episodes of nausea, vomiting, and abdominal pain, but not diarrhea. This critical analysis of scientific publications verifies the WHO provisional level for copper in drinking water (2 mg/L) as safe for human health.     

Test to determine sterile integrity of wrapped medical products at a probability of recontamination of 1 : 1,000,000.

OBJECTIVE: We developed a microbiological test to detect the penetration of airborne microorganisms through the packaging of medical products after sterilization, to meet the requirements of European standard EN 556. We applied this test method to transparent pouches. DESIGN: The microbial-barrier properties of the transparent pouches were determined using the microbial challenge test, in which the package was placed inside an exposure chamber and exposed to a defined aerosol of Saccharomyces cerevisiae. The atmospheric pressure in the chamber was periodically reduced by 0-75 millibars, to simulate weather-dependent pressure changes. Thermoresistant petri dishes filled with nutrient agar were integrated into the transparent pouches before sterilization. The packages were incubated after exposure. They were then opened and examined for colony growth. RESULTS: The number of recontaminated packages per test group (n=50) depended on the microbial bioload (defined as the number of colony-forming units per plate) to which the packages were exposed and on the size and number of decreases in atmospheric pressure. Results of multiple regression analysis showed a significant increase in the number of recontaminated packages in correlation with the product of the values for microbial bioload and the size and number of decreases in atmospheric pressure. When we analyzed the probability of recontamination of wrapped medical devices after 2 reductions in atmospheric pressure (30 millibars each) and with a surface microbial load of 10 colony-forming units per 64 cm(2), we estimated that the frequency of recontamination was 1 : 100,000. CONCLUSION: Multiple regression analysis showed that the proposed microbial challenge test is suitable to determine the probability of package recontamination at the 1 : 1,000,000 level.     

The use of asbestos-cement pipe for public water supply and the incidence of cancer in selected communities in Utah

We tested the hypothesis that there is an association between the use of asbestos-cement piping for drinking water supplies and the incidence of gastrointestinal and kidney cancer. Cancer incidence in 14 Utah communities that had used predominantly asbestos-cement piping for transporting their drinking water supplies for 20 years or more were compared to 27 Utah communities that had never used asbestos-cement piping.Cancer incidence was tabulated for 11 cancer sites for the years 1967–1976. Increased Standard Incidence Ratios (SIRs) were found for cancer of the kidney in men (SIR 192) and leukemia (a control site) in women (SIR 203). No increased SIRs were found for the opposite sex at these sites or for the other gastrointestinal sites singly or in combination. There was no increase in age-adjusted cancer incidence for the 11 sites in 4 of the 14 study communities that had used asbestos-cement piping for 30 years or more. Limitations of the study were that the water supplies were nonaggressive, and leaching from the pipes was minimal if at all. Furthermore, the latent period for observation was very short, suggesting that these results should be considered preliminary.Terry D. Sadler, M.S.C.M., is with the Rocky Mountain Center for Occupational and Environmental Health, Departments of Internal and Family and Community Medicine, University of Utah, and the Salt Lake City-County Health Department. William N. Rom, M.D., M.P.H., and Joseph L. Lyon, M.D., M.P.H., are with the Rocky Mountain Center for Occupational and Environmental Health, Departments of Internal and Family and Community Medicine, University of Utah. James O, Mason, M.D., Dr. P.H., is with the Utah Department of Health, Salt Lake City, Utah