Metal leaching in drinking water domestic distribution system: an Italian case study

The objective of this study was to evaluate metal contamination of tap water in seven public buildings in Brescia (Italy). Two monitoring periods were performed using three different sampling methods (overnight stagnation, 30-min stagnation, and random daytime). The results show that the water parameters exceeding the international standards (Directive 98/83/EC) at the tap were lead (max = 363?μg/L), nickel (max = 184?μg/L), zinc (max = 4900?μg/L), and iron (max = 393?μg/L). Compared to the total number of tap water samples analyzed (122), the values higher than limits of Directive 98/83/EC were 17?% for lead, 11?% for nickel, 14?% for zinc, and 7?% for iron. Three buildings exceeded iron standard while five buildings exceeded the standard for nickel, lead, and zinc. Moreover, there is no evident correlation between the leaching of contaminants in the domestic distribution system and the age of the pipes while a significant influence is shown by the sampling methods.     

饮用水配水系统中微生物研究方法的进展

饮用水在输配水管网中的二次污染是不容忽视的问题,对饮用水中微生物的了解有助于饮用水安全的保障。随着微生物检测技术的发展,人们对饮用水配水系统中微生物的复杂性和多样性的认识更加深入。笔者对饮用水配水系统中微生物的存在形式、数量和多样性的研究方法进行综述,包括传统培养方法,基于PCR技术的现代分子生物学方法,DNA序列分析技术和基因芯片技术等,并着重介绍这些方法的基本原理、优缺点及应用前景。     

Gastrointestinal upsets associated with ingestion of copper-contaminated water.

During 1992 and 1993 the Wisconsin Division of Health investigated five cases in which copper-contaminated drinking water was suspected of causing gastrointestinal upsets. Each of these case studies was conducted after our office was notified of high copper levels in drinking water or notified of unexplained illnesses. Our findings suggest that drinking water that contains copper at levels above the federal action limit of 1.3 mg/l may be a relatively common cause of diarrhea, abdominal cramps, and nausea. These symptoms occurred most frequently in infants and young children and among resident of newly constructed or renovated homes.     

A follow-up study of gastro-intestinal diseases related to bacteriologically substandard drinking water

In a prospective follow-up study conducted in 52 French alpine villages, one weekly water sample was taken in each village provided with untreated ground water and analyzed as to the presence of four indicator bacteria: total plate count, total coliforms, thermotolerant (fecal) coliforms, and fecal streptococci. Cases of acute gastro-intestinal disease (AGID) occurring among 29,272 inhabitants were reported through physicians, pharmacists, and primary school teachers. A loglinear model identified fecal streptococcus (FS) as the best predictor; the presence of fecal coliforms enhanced the effect of FS. The total bacteria count and the total coliforms had no independent contributions. A threshold analysis suggested that any level of indicator bacteria above zero was associated with an excess of AGID.     

Gastroenteritis associated with accidental contamination of drinking water with partially treated water

Due to human error, drinking water supplied to a new housing estate in The Netherlands was contaminated with grey water. The cohort of 921 accidentally exposed households (area A) had a higher attack rate for diarrhoea (54.1%) than a non-exposed cohort of 1529 households from an adjacent area (B) (24%) (RR 2.3, 95% CI 1.9-2.7). Household water score showed a dose-response with illness, in both areas A and B. For each 1000 inhabitants, 19.8 cases in area A, 7.0 cases in control area B (RRAB 2.2, 95% CI 1.3-3.8) and 3.3 cases in a more distant control area C (RRAC 4.6, 95% CI 2.7-8.0) were diagnosed with gastroenteritis by their general practitioner. A gastroenteritis outbreak associated with consumption of contaminated drinking water was observed in the exposed area. The use of grey water was banned in 2003, with the exception of rainwater use for flushing toilets. The risk of rainwater use is currently being investigated.     

Relation between aluminum concentrations in drinking water and Alzheimer's disease: an 8-year follow-up study

To investigate the effect of aluminum and silica in drinking water on the risk of dementia and Alzheimer's disease, the authors analyzed data from a large prospective cohort (Paquid), including 3,777 subjects aged 65 years and over living at home in 75 civil parishes in Gironde and Dordogne in southwestern France in 1988-1989. The subjects were followed for up for 8 years with an active search for incident cases of dementia or Alzheimer's disease. Mean exposure to aluminum and silica in drinking water was estimated in each area. The sample studied included 2,698 nondemented subjects at baseline, for whom components of drinking water and covariates were available. A total of 253 incident cases of dementia (with 17 exposed to high levels of aluminum), including 182 Alzheimer's disease (with 13 exposed to high aluminum levels), were identified. The relative risk of dementia adjusted for age, gender, educational level, place of residence, and wine consumption was 1.99 (95 percent CI: 1.20, 3.28) for subjects exposed to an aluminum concentration greater than 0.1 mg/liter. This result was confirmed for Alzheimer's disease (adjusted relative risk = 2.14, 95 percent CI: 1.21, 3.80). However, no dose-response relation was found. Inversely, the adjusted relative risk of dementia for subjects exposed to silica (> or = 11.25 mg/liter) was 0.74 (95 percent CI: 0.58, 0.96). These findings support the hypothesis that a high concentration of aluminum in drinking water may be a risk factor for Alzheimer's disease.     

Investigation of a community outbreak of typhoid fever associated with drinking water

Background  

This report is about the investigation of an outbreak of typhoid fever claimed three human lives and left more than 300 people suffered within one week. The aim of this report is to draw the attention of global health community towards the areas that are still far from basic human essentialities.     

Does the evidence about health risks associated with nitrate ingestion warrant an increase of the nitrate standard for drinking water?

Several authors have suggested that it is safe to raise the health standard for nitrate in drinking water, and save money on measures associated with nitrate pollution of drinking water resources. The major argument has been that the epidemiologic evidence for acute and chronic health effects related to drinking water nitrate at concentrations near the health standard is inconclusive. With respect to the chronic effects, the argument was motivated by the absence of evidence for adverse health effects related to ingestion of nitrate from dietary sources. An interdisciplinary discussion of these arguments led to three important observations. First, there have been only a few well-designed epidemiologic studies that evaluated ingestion of nitrate in drinking water and risk of specific cancers or adverse reproductive outcomes among potentially susceptible subgroups likely to have elevated endogenous nitrosation. Positive associations have been observed for some but not all health outcomes evaluated. Second, the epidemiologic studies of cancer do not support an association between ingestion of dietary nitrate (vegetables) and an increased risk of cancer, because intake of dietary nitrate is associated with intake of antioxidants and other beneficial phytochemicals. Third, 2–3 % of the population in Western Europe and the US could be exposed to nitrate levels in drinking water exceeding the WHO standard of 50 mg/l nitrate, particularly those living in rural areas. The health losses due to this exposure cannot be estimated. Therefore, we conclude that it is not possible to weigh the costs and benefits from changing the nitrate standard for drinking water and groundwater resources by considering the potential consequences for human health and by considering the potential savings due to reduced costs for nitrate removal and prevention of nitrate pollution.     

Microbiological risk associated with consumption of drinking water in developed countries

This article provides an overview of the waterborne disease (WBD) issue in developed countries (USA, Canada, UK and other European countries). The factors involved in the epidemiology of waterborne infection are analysed (microbial, social, environmental, etc.) and the main WBD etiological agents are described with particular interest to emerging pathogens (i.e. Cryptosporidium parvum, Legionella and Calicivirus). Microorganism characteristics related to water contamination risk are described and examples of waterborne outbreak are reported. A short account about the detection methods of these microorganisms in the water is given. In conclusion, some possible strategies to control waterborne microbiological risk in industrialised countries are discussed considering the application of the risk analysis and the HACCP system in the water production and the need of a WBD surveillance system.     

Faecal contamination of a municipal drinking water distribution system in association with Campylobacter jejuni infections

After heavy rains Campylobacter jejuni together with high counts of Escherichia coli, other coliforms and intestinal enterococci were detected from drinking water of a municipal distribution system in eastern Finland in August 2004. Three patients with a positive C. jejuni finding, who had drunk the contaminated water, were identified and interviewed. The pulsed-field gel electrophoresis (PFGE) genotypes from the patient samples were identical to some of the genotypes isolated from the water of the suspected contamination source. In addition, repetitive DNA element analysis (rep-PCR) revealed identical patterns of E. coli and other coliform isolates along the distribution line. Further on-site technical investigations revealed that one of the two rainwater gutters on the roof of the water storage tower had been in an incorrect position and rainwater had flushed a large amount of faecal material from wild birds into the drinking water. The findings required close co-operation between civil authorities, and application of cultivation and genotyping techniques strongly suggested that the municipal drinking water was the source of the infections. The faecal contamination associated with failures in cleaning and technical management stress the importance of instructions for waterworks personnel to perform maintenance work properly.     

一起饮水污染导致埃可病毒3O型脑膜炎暴发的调查

目的调查一起学校内多名学生发热伴头晕、头痛,或伴恶心、呕吐的感染原因与影响范围,提出控制措施。方法疑似病例定义为2012年3月1日后L学校师生中?现发热(腋温≥37℃)伴头晕、头痛、恶心、呕吐症状之一者;确诊病例为疑似病例咽拭子或肛拭子肠道通用病毒RT-PCR阳性者。病例搜索通过查阅3月1日后当地4家医院就诊记录和学校师生冈病缺课缺勤记录。采用1：2个体匹配的病例对照研究分析饮水暴露情况。采集27名病例的咽拭子和肛拭子进行肠道通用病毒RT-PCR及序列分析。4月19日采集2份直饮水机温开水样品分析细菌总数和大肠菌群。结果学校学生病例103例,罹患率4.6％(1032255)。77.7％(80／103)病例来自该校综合楼,三年级罹患率最高18.1％(721397)。流行病学曲线为持续同源暴露,饮用直饮水机温开水(OR=18.3,95％CI：2.0～169.5)和饮用生水(OR=15.5,95％CI：1.7～141.8)均是危险冈素。27名病例肠道通用病毒RT-PCR检出率为81.5％(22／27),其中9例PCR序列分析有7例为埃可病毒卸型(Echo 30)。直饮水机温开水细菌总数和大肠菌群检测结果符合标准。结论该次疫情是由Echo 30导致的一起学校内病毒性脑膜炎暴发,饮水是危险因素,不同于以往的人传人模式,值得关注。     

Deficiencies in drinking water distribution systems in developing countries

Rapidly growing populations and migration to urban areas in developing countries has resulted in a vital need for the establishment of centralized water systems to disseminate potable water to residents. Protected source water and modern, well-maintained drinking water treatment plants can provide water adequate for human consumption. However, ageing, stressed or poorly maintained distribution systems can cause the quality of piped drinking water to deteriorate below acceptable levels and pose serious health risks. This review will outline distribution system deficiencies in developing countries caused by: the failure to disinfect water or maintain a proper disinfection residual; low pipeline water pressure; intermittent service; excessive network leakages; corrosion of parts; inadequate sewage disposal; and inequitable pricing and usage of water. Through improved research, monitoring and surveillance, increased understanding of distribution system deficiencies may focus limited resources on key areas in an effort to improve public health and decrease global disease burden.     

Achieving compliance with the radium standards for drinking water in a midwestern community: a case study

The problem of elevated levels of radium in the drinking-water supply of DeKalb, Illinois, a Midwestern community about 65 miles west of Chicago with approximately 35,000 residents, has been a contentious issue for over a decade. The central players in the controversy include a group of concerned citizens, city officials, the Illinois Pollution Control Board, the Illinois Environmental Protection Agency, and the U.S. Environmental Protection Agency (U.S. EPA). Achieving a satisfactory resolution to the problem has been a long, drawn-out process that illustrates how ill-timed proposals, changing risk assessments, different perceptions of risk, and the high costs of compliance can influence the direction of risk management decisions. The purpose of this study is to analyze how these factors sustained the debate and prevented an expeditious solution to the problem. The study uses document analysis as its primary research tool. The questions raised by the controversy, along with their implications for environmental policy, are discussed, as are some of the more important lessons learned from the case. Because of many uncertainties, there were no clear winners in the controversy, although, in the context of the most recent U.S. EPA risk assessments, the community is now poised for better protection from the potential dangers of radium in drinking water than it might have been had citizen action been absent.     

An outbreak of Norwalk-like gastroenteritis associated with contaminated drinking water at a caravan park

Abstract: During the 1989 Christmas holiday period, a large outbreak of gastroenteritis occurred among persons staying at a caravan park in southern New South Wales. Review of local hospital records found that 77 per cent of patients presenting with infective diarrhoea between 29 December and 3 January had stayed at the caravan park. In a retrospective cohort study we compared rates of illness among caravan park patrons exposed to different water sources. Stools were tested for pathogens and convalescent sera for viral antibodies. Rain and reticulated river water sampled from the caravan park were tested for bacteria and viruses. Of 351 persons interviewed at the caravan park, 305 (87 per cent) reported an illness characterised by diarrhoea, vomiting and abdominal pain. Of 196 persons who used reticulated river water for drinking or ablutions, 175 (89 per cent) became ill compared with 47 of 72 persons (65 per cent) who did not use this water (relative risk 1.4, 95 per cent confidence interval 1.2 to 1.6). The outbreak was probably caused by a 27–28 nm small round structured virus found in the stool from one ill person. High levels of faecal coliforms in the reticulated river water and enterovirus in sediment samples suggest that the outbreak was caused by sewage contaminating the reticulated river water through a break in the pipe directly over the underground water tanks. To prevent such outbreaks, poor water and sewerage system layouts should be avoided and nonpotable water should be clearly labelled. Where feasible, all camping-ground water should stem from town supplies.     

Nitrates in drinking water and methemoglobin levels in pregnancy: a longitudinal study

Background  

Private water systems are more likely to have nitrate levels above the maximum contaminant level (MCL). Pregnant women are considered vulnerable to the effects of exposure to high levels of nitrates in drinking water due to their altered physiological states. The level of methemoglobin in the blood is the biomarker often used in research for assessing exposure to nitrates. The objective of this study was to assess methemoglobin levels and examine how various factors affected methemoglobin levels during pregnancy. We also examined whether differences in water use practices existed among pregnant women based on household drinking water source of private vs. public supply.