Environmental impact on the bacteriological quality of domestic water supplies in Lagos,Nigeria

OBJECTIVE: To assess the impact of town planning, infrastructure, sanitation and rainfall on the bacteriological quality of domestic water supplies. METHODS: Water samples obtained from deep and shallow wells, boreholes and public taps were cultured to determine the most probable number of Escherichia coli and total coliform using the multiple tube technique. Presence of enteric pathogens was detected using selective and differential media. Samples were collected during both periods of heavy and low rainfall and from municipalities that are unique with respect to infrastructure planning, town planning and sanitation. RESULTS: Contamination of treated and pipe distributed water was related with distance of the collection point from a utility station. Faults in pipelines increased the rate of contamination (p<0.5) and this occurred mostly in densely populated areas with dilapidated infrastructure. Wastewater from drains was the main source of contamination of pipe-borne water. Shallow wells were more contaminated than deep wells and boreholes and contamination was higher during period of heavy rainfall (p<0.05). E. coli and enteric pathogens were isolated from contaminated supplies. CONCLUSIONS: Poor town planning, dilapidated infrastructure and indiscriminate siting of wells and boreholes contributed to the low bacteriological quality of domestic water supplies. Rainfall accentuated the impact.     

An evaluation of the hydrogen sulphide water screening test and coliform counts for water quality assessment in rural Malaysia.

The H2S water screening test and the membrane filtration faecal coliform count were compared with Escherichia coli counts for water samples collected from household water sources and domestic drinking water in rural Malaysia. Water samples were taken from 151 wells, 44 taps supplying water from the treated municipal supply and 192 domestic stored water supplies. E. coli were detected in 20% of the samples (42% of wells, 7% of tap water and 6% of drinking water). Excellent correlation (Spearman's rank correlation rs = 0.93) was found between the faecal coliform and E. coli counts for all sample types. The H2S method was poorly correlated whether read at 18 or 30 h. False positive rates were highest for well water, and false negative rates were highest for both well and drinking water samples, with low E. coli counts. The faecal coliform test was an excellent predictor of the presence of E. coli in these water samples, while the H2S test was very inadequate.     

A community-based bacteriological study of quality of drinking-water and its feedback to a rural community in Western Maharashtra, India

A longitudinal study of the bacteriological quality of rural water supplies was undertaken for a movement towards self-help against diseases, such as diarrhoea, and improved water management through increased community participation. Three hundred and thirteen water samples from different sources, such as well, tank, community standpost, handpumps, percolation lakes, and streams, and from households were collected from six villages in Maharashtra, India, over a one-year period. Overall, 49.8% of the 313 samples were polluted, whereas 45.9% of the samples from piped water supply were polluted. The quality of groundwater was generally good compared to open wells. Irregular and/or inadequate treatment of water, lack of drainage systems, and domestic washing near the wells led to deterioration in the quality of water. No major diarrhoeal epidemics were recorded during the study, although a few sporadic cases were noted during the rainy season. As a result of a continuous feedback of bacteriological findings to the community, perceptions of the people changed with time. An increased awareness was observed through active participation of the people cutting across age-groups and different socioeconomic strata of the society in village activities.     

Quality of Water the Slum Dwellers Use: The Case of a Kenyan Slum

As a result of rapid urbanization in a context of economic constraints, the majority of urban residents in sub-Saharan Africa live in slums often characterized by a lack of basic services such as water and sewerage. Consequently, the urban poor often use inexpensive pit latrines and at the same time may draw domestic water from nearby wells. Overcrowding in slums limits the adequate distance between wells and pit latrines so that micro-organisms migrate from latrines to water sources. Sanitary practices in these overcrowded slums are also poor, leading to contamination of these wells. This study sought to assess sanitary practices of residents of a Kenyan urban slum and fecal contamination of their domestic water sources. This cross-sectional study involved 192 respondents from Langas slum, Kenya. Forty water samples were collected from the water sources used by the respondents for laboratory analysis of coliforms. Of these 40 samples, 31 were from shallow wells, four from deep wells, and five from taps. Multiple-tube fermentation technique was used to enumerate coliform bacteria in water. The study found that most people (91%) in the Langas slum used wells as the main source of domestic water, whereas the rest used tap water. Whereas most people used pit latrines for excreta disposal, a substantial percentage (30%) of children excreted in the open field. The estimated distance between the pit latrines and the wells was generally short with about 40% of the pit latrines being less than 15 m from the wells. The main domestic water sources were found to be highly contaminated with fecal matter. Total coliforms were found in 100% of water samples from shallow wells, while 97% of these samples from shallow wells were positive for thermotolerant coliforms. Three out of the four samples from deep wells were positive for total coliforms, while two of the four samples were positive for thermotolerant coliforms. None of the samples from taps were positive for either total or thermotolerant coliforms. Because the presence of thermotolerant coliforms in water indicates fecal contamination, facilitated by the proximity between the wells and pit latrines, the study suggests that the pit latrines were a major source of contamination of the wells with fecal matter. However, contamination through surface runoff during rains is also plausible as indiscriminate excreta disposal particularly by children was also common. Owing to the fecal contamination, there is a high possibility of the presence of disease pathogens in the water; thus, the water from the wells in Langas may not be suitable for human consumption. To address this problem, treatment of the water at community or household level and intensive behavioral change in sanitary practices are recommended. Efforts should be made to provide regulated tap water to this community and to other slums in sub-Saharan Africa where tap water is not accessible. However, more sampling of different water sources is recommended.     

Prevalence of Shiga toxin-, intimin- and haemolysin genes in Escherichia coli isolates from drinking water supplies in a rural area of Austria

Literature harbours several reports of potable water-associated outbreaks. We studied the prevalence of Shiga toxin- (stx1/2), intimin- (eae) and haemolysin (hlyA) genes in Escherichia coli isolates from drinking water of private and public water supplies in a rural area of Upper Austria; 2633 water samples were gained between November 2000 and December 2003. Two hundred and eighty of these water samples were positive for E. coli (10.6%). Of these, 101 samples were drawn from drilled wells (36%), 96 from dug wells (34%), 61 from springs (22%) and 22 from water supplies without available information on technical details (8%); 141 of the samples were from public water supplies, 139 from private water supplies. Eleven of the E. coli isolates were found to be positive for one of the investigated virulence genes (3.9%): one isolate yielded stx2, seven eae, and three isolates had hlyA. The presence of these genes underlines the importance of control of water quality in public and also private water supplies.     

Safe water for Africa

Most morbidity in Africa is linked to unsafe water supplies and a lack of adequate sanitation facilities. According to official government statistics, only 57% of Africans had access to safe water in 1990. The treatment of contaminated water sources or the development of alternative, cleaner water sources is insufficient. The provision of community water points must be integrated with latrine construction and intensive hygiene education based on traditional cultural activities. In rural areas, where people generally collect water from surface sources or shallow wells, intensive education is required to convince community members of the health benefits of improved sources (e.g., protected wells or bore holes with hand pumps), especially when these sources are more distant. In high-density urban areas, even water from the taps and public standpipes is often contaminated and household treatment of drinking water must be promoted. Greater emphasis is being placed on selecting equipment that can be maintained with local technical and organizational capacities and strengthening local maintenance and repair capacities through training village-based mechanics and establishing networks of spare parts suppliers.     

First investigations into the prevalence of Cryptosporidium and Giardia spp. in Hungarian drinking water

Safe drinking water is a top priority in preventing disease outbreaks and is of general concern to everyone. This study examines the occurrence of Cryptosporidium and Giardia in Hungarian drinking water supplies for the first time. A total of 76 raw and drinking water samples were examined using the U.S. EPA Method 1623. From these 15 of 34 (48.4%) raw water samples tested positive for Giardia and 7 (26.6%) for Cryptosporidium. Twelve of 45 (26.7%) drinking water samples were positive for Giardia and 6 (13.3%) for Cryptosporidium. Overall, Giardia cysts and/or Cryptosporidium oocysts were detected in 48% of the raw water samples and 35% of the drinking water samples. The highest levels in drinking water were found to be 3 oocysts/100 litres of Cryptosporidium and 63.6 cysts/100 litres for Giardia, enough to cause giardiasis. The highest levels in raw water were 1,030 cysts/100 litres for Giardia and 50 oocysts/100 litres for Cryptosporidium and higher oocyst densities were associated with source water receiving effluents from sewage treatment plants or originating from a forest environment. In addition to this monitoring, riverbank filtrated water and raw water from the River Danube in Budapest were monitored in order to ascertain protozoan removal efficiency of riverbank filtration (RBF). A total of 157 samples, including 87 samples from the River Danube and 70 samples post RBF, were examined. Cryptosporidium and Giardia were detected regularly in the river water but never in riverbank filtered water suggesting the effectiveness of RBF as a purification method. The occurrence of Cryptosporidium oocysts and Giardia cysts in the investigated water supplies may require the water utilities and water authorities in Hungary to apply additional monitoring and treatment and/or watershed controls.     

Microbiological quality of drinking water of urban and rural communities,Brazil

OBJECTIVE: To evaluate the microbiological quality of treated and untreated water samples came from urban and rural communities and to examine the relationship between coliforms occurrence and average water temperature, and a comparison of the rainfall levels. METHODS: A sample of 3,073 untreated and treated (chlorinated) water from taps (1,594), reservoir used to store treated water (1,033), spring water (96) and private well (350) collected for routine testing between 1996 and 1999 was analyzed by the multiple dilution tube methods used to detect the most probable number of total and fecal coliforms. These samples were obtained in the region of Maring , state of Paran , Brazil. RESULTS: The highest numbers water samples contaminated by TC (83%) and FC (48%) were found in the untreated water. TC and FC in samples taken from reservoirs used to store treated water was higher than that from taps midway along distribution lines. Among the treated water samples examined, coliform bacteria were found in 171 of the 1,033 sampling reservoirs. CONCLUSIONS: Insufficient treatment or regrowth is suggested by the observation that more than 17% of these treated potable water contained coliform. TC and FC positive samples appear to be similar and seasonally influenced in treated water. Two different periods must be considered for the occurrence of both TC and FC positive samples: (i) a warm-weather period (September-March) with high percentage of contaminated samples; and (ii) cold-weather period (April-August) were they are lower. Both TC and TF positive samples declined with the decreased of water temperature.     

First investigations into the prevalence of Cryptosporidium and Giardia spp. in Hungarian drinking water

Safe drinking water is a top priority in preventing disease outbreaks and is of general concern to everyone. This study examines the occurrence of Cryptosporidium and Giardia in Hungarian drinking water supplies for the first time. A total of 76 raw and drinking water samples were examined using the U.S. EPA Method 1623. From these 15 of 34 (48.4%) raw water samples tested positive for Giardia and 7 (26.6%) for Cryptosporidium. Twelve of 45 (26.7%) drinking water samples were positive for Giardia and 6 (13.3%) for Cryptosporidium. Overall, Giardia cysts and/or Cryptosporidium oocysts were detected in 48% of the raw water samples and 35% of the drinking water samples. The highest levels in drinking water were found to be 3 oocysts/100 litres of Cryptosporidium and 63.6 cysts/100 litres for Giardia, enough to cause giardiasis. The highest levels in raw water were 1,030 cysts/100 litres for Giardia and 50 oocysts/100 litres for Cryptosporidium and higher oocyst densities were associated with source water receiving effluents from sewage treatment plants or originating from a forest environment. In addition to this monitoring, riverbank filtrated water and raw water from the River Danube in Budapest were monitored in order to ascertain protozoan removal efficiency of riverbank filtration (RBF). A total of 157 samples, including 87 samples from the River Danube and 70 samples post RBF, were examined. Cryptosporidium and Giardia were detected regularly in the river water but never in riverbank filtered water suggesting the effectiveness of RBF as a purification method.     

Detection and characterisation of Giardia and Cryptosporidium in Hungarian raw, surface and sewage water samples by IFT, PCR and sequence analysis of the SSUrRNA and GDH genes

We investigated the prevalence of Giardia and Cryptosporidium species and analysed the genotypes in 36 samples collected from different water sources and various geographic areas in Hungary. Samples were collected from drinking water and sewage treatment plants and from the recreation area of Lake Balaton. The (oo)cysts were purified according to the US EPA 1623 method and they were detected by immunofluorescence test (IFT). Genomic DNA was extracted from all samples and then the GDH target gene for Giardia and the SSUrDNA for both Giardia and for Cryptosporidium species were amplified by PCR. 24 out of 36 samples (67%) were Giardia positive and 15 (42%) were Cryptosporidium positive by IFT. PCR confirmed that 13 out of 36 samples (36%) were Giardia positive and 10 (28%) contained Cryptosporidium. Twelve Giardia and two Cryptosporidium PCR products were successfully sequenced. In seven samples G. lamblia Assemblage A and in one sample Assemblage B and in four cases Assemblages A and B have been found. In one sample C. parvum and in the other separate sample C. meleagridis were detected. Sequence analysis revealed a new subtype of G. duodenalis complex, clustered close to the Assemblage A group. This study provides the first report on simultaneous detection and genotyping of G. duodenalis and Cryptosporidium species from water supplies in Hungary.     

Legionella contamination of hospital water supplies: monitoring of private healthcare facilities in Bologna, Italy

The hot water supplies of 11 private healthcare facilities in the city of Bologna, Italy, were monitored for the presence of Legionella spp. Four samplings were made in each establishment over a period of one year and in total 121 samples were collected from distribution points situated near the water-boiler and inside the wards (taps and showers). Legionellae were recovered from all the water supplies in question: Legionella spp. in 86.8% of samples, L. pneumophila in 82.6% of samples. L. pneumophila was found in all the water supplies at levels averaging above 10(4)cfu/L in five health facilities and reaching a maximum concentration of 10(7)cfu/L. The only parameter to have affected the presence of legionellae was the water temperature, which was seen to be inversely correlated to the concentration of Legionella spp. Despite the high levels of contamination from L. pneumophila, no cases of nosocomial Legionnaires' disease were reported during the period of the study.     

Significance of private water supply wells in a rural Nevada area as a route of exposure to aqueous arsenic

In many rural areas domestic drinking water needs are met by a mixture of public water supplies and private water supplies. Private supplies are not subject to the regulations and management requirements of the Safe Drinking Water Act (SDWA). Amendments to the SDWA recently lowered the standard for arsenic from 50 to 10 ppb in public water supplies (effective in 2006). Churchill County, Nevada, has approximately 25,000 residents. Slightly more than half (13,500) rely on private domestic wells for water supply. Ample data and media publicity about high arsenic concentrations in water supplies and a federally led investigation of a leukaemia cluster suggested that residents of the county would be aware that arsenic concentrations in private wells were highly likely to exceed the 10 ppb standard. A survey carried out in 2002 showed that a majority of respondents (72%) consumed water from private wells and among them a minority (38%) applied treatment. Maximum, median and minimum concentrations of arsenic from all samples (n = 351) were 2,100, 26 and < 3 ppb, respectively. Seventy-four per cent of all samples exceeded 10 ppb. A majority (87%) of those who applied treatment consumed tap water. The relatively low rate of application of treatment suggested that these rural residents did not recognize that consumption could have associated health risks. However, those who applied treatment were approximately 0.3 times as likely to be consuming water with > 10 ppb arsenic than those who consumed water that was not treated. In areas where concentrations of arsenic have been demonstrated to be high, it may be important to conduct a focused educational effort for private well owners to ensure that they take the steps needed to assess and reduce risks associated with contaminants found in tap water, including arsenic. An educational effort could include promoting sampling efforts to determine the magnitude of arsenic concentrations, explaining the risk associated with arsenic consumption and providing information about choices for home treatment systems that are likely to be effective in removing arsenic. This may be especially important in rural areas where adverse health effects are not evident to local populations.     

Radon in public water supplies in Migdonia basin, Central Macedonia, Northern Greece

The main objective of this work is the accurate measurement of radon concentration in the public water supplies of the Migdonia basin in Northern Greece. The main aim is to localize the sub-areas that present high radon concentrations in water and to inform the local authorities so that more detailed studies might be set up in these areas. About 80 samples from special bore holes and taps that supply the local population with fresh water were collected in order to obtain detailed radon measurements. For the analyses, a liquid scintillation counting system, using the Packard protocol for measuring radon in water, was employed. The results of the investigation show that radon concentrations in these public water supplies are significant. The concentrations ranged from background concentrations to 170 Bq x L(-1). The level of 50 Bq x L(-1) is exceeded in 23% of water supplies. These preliminary results with initial data interpretation and inter-comparison assessment are presented. These results of the analyses showed that elevated radon concentrations were detected in water samples from an area at the western part of the Lake Volvi, due probably to the local intense tectonism, and from a village above the Lake Koronia.     

Microbiological analysis of mineral water and drinking water of reservoir supplies,Brazil

The aim of this study was to evaluate the microbiological quality of different commercial mineral water brands, wells and reservoir supplies in surrounding areas of the city of Marília, Brazil, to determine the amount of total and fecal coliforms. Eighteen samples of each source (mineral and reservoir supplies) were analyzed using Colilert Technique in cellophane. The results revealed that one sample of mineral water and one sample collected from the reservoir supply had been contaminated by a bacterium of the total coliform group, and there were found one bacterium/100 ml of water. None of the water samples showed contamination by fecal coliforms.     

High levels of faecal contamination in drinking groundwater and recreational water due to poor sanitation,in the sub-rural neighbourhoods of Kinshasa,Democratic Republic of the Congo

In many urban and peri-urban areas of developing countries, shallow wells and untreated water from urban rivers are used for domestic purposes, including drinking water supply, population bathing and irrigation for urban agriculture. The evaluation and monitoring of water quality are therefore necessary for preventing potential human risk associated with the exposure to contaminated water. In this study, physicochemical and bacteriological parameters were assessed in an urban river (named Kokolo Canal/Jerusalem River) draining the municipality of Lingwala (City of Kinshasa, Democratic Republic of the Congo) and in two shallow wells used as drinking water supplies, during the wet and dry seasons in order to estimate the seasonal variation of contamination. The faecal indicator bacteria (FIB) isolated strains (Escherichia coli (E. coli) and Enterococcus (ENT)) from water and surface sediment, were characterized for human-specific bacteroides by molecular approach. The results revealed very high faecal contamination of water from the shallow wells, and of water and sediments from the river, during both wet and dry seasons. During the wet season, E. coli reached the values of 18.6?×?10⁵ and 4.9?×?10⁵?CFU 100?mL^?1 in Kokolo Canal and shallow wells, respectively; and Enterococcus reached the values of 7.4?×?10⁴ and 2.7?×?10⁴?CFU 100?mL^?1. Strong mutually positive correlation was observed between E. coli and ENT, with the range of R-value being 0.93?<?r?<?0.97 (p-value?<?0.001, n?=?15). The PCR assays for human-specific Bacteroides indicated that more than 98% of 500 isolated FIB strains were of human origin, pointing out the effect of poor household sanitation practices on surface water but also on groundwater contamination. The water samples from the shallow wells and Kokolo Canal were highly polluted with faecal matter in both seasons. However, the pollution level was significantly higher during the wet season compared to the dry season. Physicochemical analysis revealed also very high water electrical conductivity, with values much higher than the recommended limits of the World Health Organization guideline for drinking water. These results highlight the potential human health risk associated with the exposure to water contamination from shallow wells and Kokolo Canal, due to the very high level of human FIB. Rapid, unplanned and uncontrolled population growth in the city of Kinshasa is increasing considerably the water demand, whereas there is a dramatic lack of appropriate sanitation and wastewater facilities, as well as of faecal sludge (and solid waste) management and treatment. The lack of hygiene and the practice of open defecation is leading to the degradation of water quality, consequently the persistence of waterborne diseases in the neighbourhoods of sub-rural municipalities, and there is a growing threat to the sustainability to water resources and water quality. The results of this study should encourage municipality policy and strategy on increasing the access to safely managed sanitation services; in order to better protect surface water and groundwater sources, and limit the proliferation of epidemics touching regularly the city.     

Legionella pneumophila in a hospital water system following a nosocomial outbreak: prevalence, monoclonal antibody subgrouping and effect of control measures

Swabs and water samples from a hospital water system were cultured for legionellae over an extended period. Legionella pneumophila serogroup 1, including outbreak associated strains, were isolated in small numbers from approximately 5% of these samples despite implementation of the current DHSS/Welsh Office regulations. No cases of nosocomial legionnaires' disease were proven during the study. Physical cleaning and chemical sterilization of taps, and replacement of washers with 'approved' brands did not eradicate the organisms. Eradication of legionellae in hospital water supplies appears to be unnecessary in preventing nosocomial legionnaires' disease provided the current DHSS/Welsh Office recommendations are implemented.     

Effects of sampling,shipping, and storage on total organic carbon levels in water samples

Conclusions The sampling, storage, and shipping conditions used in this study were found to have little effect on the TOC levels in tap and river water samples. Therefore, samples from distant water supplies can readily be shipped to a central laboratory for reliable TOC determination (RSD<5%), if care is taken in bottle preparation and in sampling, and if the described procedures are followed. However, the procedures for sampling, storage and/or shipping of water samples with low TOC content cannot be recommended, due to contamination of the samples.     

地震后江油市水源水检测结果分析

目的了解地震后江油市生活用水水源的污染状况,为保障生活饮用水卫生安全提供决策依据。方法采用方便抽样方法,采集震后9～25d江油太平镇和三合镇灾民居住点附近的水源水74份进行检测。对14份水质变黑的井水先进行铁和锰检测,再进行全分析。结果抽检水源水总合格率为38.5%,河水合格率为34.4%,井水合格率为57.1%。不合格指标中,大肠菌群、浑浊度占的比重最大。有6份井水中的铁锰超标。结论震后江油太平镇和三合镇的水源水受到较大污染,存在安全隐患,检测结果对灾民安全用水有重要指导意义。     

Bacteriological and physicochemical quality of drinking water and hygiene-sanitation practices of the consumers in bahir dar city, ethiopia

Background

Lack of safe drinking water, basic sanitation, and hygienic practices are associated with high morbidity and mortality from excreta related diseases. The aims of this study were to determine the bacteriological and physico-chemical quality of drinking water and investigate the hygiene and sanitation practices of the consumers in Bahir Dar City, Ethiopia.

Methods

A cross sectional prospective study was conducted in Bahir Dar City from October–December, 2009. Water samples were collected from 35 private taps and 35 household water containers for bacteriological analysis. The turbidity, pH, temperature and turbidity were measured immediately after collection. Finally, the hygiene-sanitation practices of the consumers were surveyed using interview.

Results

Twenty seven (77.1%) of the household water samples had high total coliforms counts. Twenty (57.1%) household water samples and 9 (25.7%) of the tap water samples had no residual free chlorine. Sixteen (45.7%) household water samples had very high risk score to thermotolerant coliforms. Eight (22.9%) tap water samples had low risk score for total coliforms whereas 21(60%) tap water had very low risk score for thermotolerant coliforms. Twelve (34.3%) of the consumers collect water without contact with their hand and 9(25.7%) wash their hands with soap after visiting toilet.

Conclusion

Water supplies at tap and household water containers were contaminated with bacteria. Poor sanitation, low level of hygiene, uncontrolled treatment parameters are the causes for contamination. Control of physico-chemical parameters and promoting good hygiene and sanitation are recommended.     

铜水管的卫生安全研究

目的：评价铜水管对水质的影响。方法：采集1家国外企业和2家国内企业生产的24根直径15mm、长0．5m的紫铜水管和20个黄铜管件进行24h浸泡实验并检测水质变化。选择北京市以市政管网为水源使用铜水管超过1a的2个用户和使用少于3个月的2个用户检测末梢水水质变化。结果：浸泡实验显示浸泡水中溶解性总固体、铜、铅、锌、镍浓度不同程度超标,pH值、余氯、总碱度、总硬度、硫酸盐、氯化物、硝酸盐、铬、镉、锡、砷浓度达标。使用铜水管的用户末梢水中总硬度、镉、镍浓度不同程度超标,其余指标均达标。结论：紫铜水管配合黄铜管件使用存在很多卫生学问题,尤其是黄铜管件,其浸泡水卫生学指标超标是铜水管水质超标的主要原因之一,但铜水管水质超标的原因不能完全归咎于黄铜管件。现场调查显示铜水管用户末梢水部分指标超标与使用不锈钢水龙头有关,故铜水管基本满足我国饮用水质卫生要求。