Assessment of microbiological water quality and its relation to human health in Gaza Governorate, Gaza Strip

Quantitative microbial risk assessment for Escherichia Coli O157: H7 via drinking water in the Gaza Strip, Palestine

Introduction

Microbial contamination of drinking water, particularly by pathogens such as Escherichia coli O157: H7, is a significant public health concern worldwide, especially in regions with limited access to clean water like the Gaza Strip. However, few studies have quantified the disease burden associated with E. coli O157: H7 contamination in such challenging water management contexts.

Objective

This study aimed to conduct a comprehensive Quantitative Microbial Risk Assessment to estimate the annual infection risk and disease burden attributed to E. coli O157: H7 in Gaza's drinking water.

Methods

Applying the typical four steps of the Quantitative Microbial Risk Assessment technique-hazard identification, exposure assessment, dose-response analysis, and risk characterization-the study assessed the microbial risk associated with E. coli O157: H7 contamination in Gaza's drinking water supply. A total of 1317 water samples from various sources across Gaza were collected and analyzed for the presence of E. coli O157: H7. Using Microsoft ExcelTM and @RISKTM software, a Quantitative Microbial Risk Assessment model was constructed to quantify the risk of infection associated with E. coli O157: H7 contamination. Monte Carlo simulation techniques were employed to assess uncertainty surrounding input variables and generate probabilistic estimates of infection risk and disease burden.

Results

Analysis of the water samples revealed the presence of E. coli O157: H7 in 6.9% of samples, with mean, standard deviation, and maximum values of 1.97, 9.74, and 112 MPN/100 ml, respectively. The risk model estimated a median infection risk of 3.21 × 10-01 per person per year and a median disease burden of 3.21 × 10-01 Disability-Adjusted Life Years per person per year, significantly exceeding acceptable thresholds set by the WHO.

Conclusion

These findings emphasize the urgent need for proactive strategies to mitigate public health risks associated with waterborne pathogens in Gaza.

The role of corporate social responsibility and government incentives in installing industrial wastewater treatment plants: SEM-ANN deep learning approach

Contaminated industrial wastewater is one of the severe causes of health diseases. The wastewater treatment trend in developing countries is less, and governments are not strictly pursuing the wastewater management protocols adopted by firms. To study the intention to install wastewater treatment plants at the firm level and provide policy suggestions to the developing countries' governments, we have collected a cross-sectional dataset from manufacturing firms. We have presented an integrated model based on the theory of planned behaviour and tested our proposed model by implying SEM-ANN deep learning techniques. Results revealed that Environmental knowledge, installation cost, firm reputation, and corporate social responsibility positively influence firm management's intention to install wastewater treatment plants, but awareness of the risk associated with contaminated wastewater has a negative influence. On the other hand, Government incentives do not influence the process. In addition, our study has found that firm size moderates the relationship between explained and exploratory variables. Our study provided valuable insight into the available literature and provided some policy suggestions to developing countries' governments to cope with water scarcity and health issues caused by contaminated industrial wastewater.

Multiscalar Evaluation of the Water Distribution System and Diarrheal Disease Risk in Addis Ababa, Ethiopia

Despite growing urbanization, our understanding of the impacts of water and sanitation on human health has largely come from studies in rural sectors. To this end, we collected data at both regional (water quality measures from water treatment systems) and community (cross-sectional surveys) scales to examine determinants of enteric pathogen infection and diarrheal disease among infants in Addis Ababa, Ethiopia. Regionally, the Legedadi water treatment plant had significantly lower heterotrophic plate counts, total coliform counts, and fecal coliform counts compared with the Gefersa water treatment plant. The number of pathogen types in infant stool also differed by plant. Decreases in chlorine levels and increases in the relative abundance of Gammaproteobacteria with distance from treatment plants suggest a compromised water distribution system. In communities, infants in households that obtained water from yard pipes or public taps had significantly lower odds of diarrhea compared to households that had water piped into their dwellings (OR = 0.35, 95% CI 0.16, 0.76, and OR = 0.39, 95% CI 0.15, 1.00, respectively). Similarly, infants in households that boiled or filtered water had significantly lower odds of diarrhea compared to households that did not treat water (OR = 0.40, 95% CI 0.19, 0.86 and OR = 0.23, 95% CI 0.06, 0.84, respectively). Integrating multiscalar data better informs the health impacts of water in urban settings.

Worldwide Surveillance Actions and Initiatives of Drinking Water Quality: A Scoping Review

This study identified and mapped worldwide surveillance actions and initiatives of drinking water quality implemented by government agencies and public health services. The scoping review was conducted between July 2021 and August 2022 based on the Joanna Briggs Institute method. The search was performed in relevant databases and gray literature; 49 studies were retrieved. Quantitative variables were presented as absolute and relative frequencies, while qualitative variables were analyzed using the IRaMuTeQ software. The actions developed worldwide and their impacts and results generated four thematic classes: (1) assessment of coverage, accessibility, quantity, and drinking water quality in routine and emergency situations; (2) analysis of physical-chemical and microbiological parameters in public supply networks or alternative water supply solutions; (3) identification of household water contamination, communication, and education with the community; (4) and investigation of water-borne disease outbreaks. Preliminary results were shared with stakeholders to favor knowledge dissemination.

Mapping and Visualizing Global Knowledge on Intermittent Water Supply Systems

Intermittent water supply systems (IWSSs) are prevalent in most developing countries and some developed ones. Their usage is driven by necessity rather than as a principal objective, mostly due to technical and economic deficiencies. Major health risks and socio-economic inequities are associated with such systems. Their impacts are aggravated by climate changes and the COVID-19 crisis. These are likely to have profound implications on progress toward advancing sustainable development goals (SDGs). Motivated by providing a comprehensive overview of global knowledge on IWSSs, the present work proposed to track and analyze research works on IWSSs utilizing bibliometric techniques and visual mapping tools. This includes investigating the trends and growth trajectories of research works on IWSSs and analyzing the various approaches proposed to expand our understanding with respect to the management, modeling, optimization, and impacts of IWSSs. The national and international contributions and collaboration figures are further analyzed at country, institution, author, and source levels. This analysis indicates that research works conducted on IWSSs have certain expectations in terms of productivity (total global productivity; 197 documents). The United States was the best country in terms of productivity (58 documents; 29.4%), while the Water Switzerland journal was the most productive journal (19 documents; 9.6%). The impacts of IWSSs on health and well-being have attracted considerable attention. The outcomes showed deep and justified worries in relation to the transition from intermittent to continuous supply, equity, and mitigating the health risks associated with IWSSs in the foreseen future. The utilization of artificial intelligence techniques and expert systems will drive and shape future IWSS-related research activities. Therefore, investments in this regard are crucial.

Comprehensive Risk Assessment of Health-Related Hazardous Events in the Drinking Water Supply System from Source to Tap in Gaza Strip, Palestine

Background

The traditional approach in the management of the quality drinking water, and relying on end-product testing, has proven ineffective in protecting public health. Therefore, the transition to a systematic approach in drinking water supply systems management from the source to the consumer tap was taken as a water safety plan (WSP).

Objective

The study aims to investigate the health-related hazardous events in order to decide on the best risk-reduction strategies in the supply of drinking water in the Gaza strip.

Methods

A semiquantitative matrix method for risk assessment was applied. Also, chlorine residual, electrical conductivity, and nitrate concentration further tested in 109 water wells, 109 small-scale water desalination plants, 197 tanker trucks, and 384 households distributed over five governorates of the Gaza strip.

Results

The mean of the measured chlorine residual values was less than the recommended national and international limits (0.2–1 mg/liter). The mean of electrical conductivity at catchment points and household municipal water taps was 2165.1 μS·cm⁻¹ and 2000 μS·cm⁻¹, respectively. Furthermore, zero percent of water samples met the recommended criteria, indicating that the groundwater in the Gaza strip is nonpotable. Only 12.8% and 8.8% of water samples met the permissible levels at catchment areas and municipal water at household, respectively, indicating sever health impacts on the public. Moreover, the most hazardous events were related to high levels of groundwater salinity, the low level of disinfection, the effect of electricity outages on the efficiency of the desalination process, and leakage of water from the tanker truck tank reservoirs. Therefore, urgent interventions are required to improve the quality of water and to mitigate the possible health effects.

Conclusion

The prioritization of hazardous events that are proportional to the degree of their attributed risk could help guide in making the right risk-reduction decisions. Urgent interventions are required to improve the quality of water and to mitigate the possible health effects.

Epidemiology of Taenia saginata taeniosis/cysticercosis: a systematic review of the distribution in the Middle East and North Africa

BACKGROUND

The zoonotic parasite Taenia saginata utilizes bovines as an intermediate host (causing cysticercosis) and humans as the definitive host (causing taeniosis). The public health burden of T. saginata is assumed to be low, but the economic burden is large, due to the resources utilized in the detection and condemnation of infected carcasses and carcass parts. As part of a collaborative effort to synthesize worldwide epidemiological data on this parasite, we present here the results of a systematic review on the distribution of T. saginata taeniosis and bovine cysticercosis in the Middle East and North Africa (MENA).

METHODS

Information on the occurrence and prevalence of T. saginata taeniosis and cysticercosis in the MENA region was obtained through a systematic review of published and grey literature, including OIE reports, published between January 1st, 1990 and December 31st, 2017.

RESULTS

A total of 63 publications were retrieved across the 21 MENA countries. Taenia saginata taeniosis was reported in 11 of these countries, whereas unspecified taeniosis was reported for a further seven. Microscopy-based prevalence values ranged between 0.02-8.6%. Bovine cysticercosis prevalence estimates based on meat inspection were only reported for Egypt and Israel, with prevalence data ranging between 0.2-20% and 0.1-9.1% for cattle and buffaloes, respectively. The presence of bovine cysticercosis could be confirmed for 10 additional countries through OIE reports.

CONCLUSIONS

Human taeniosis occurrence was confirmed for 86% (18/21) of the countries in the MENA region, although in several of these countries the species responsible was not specified. Religious prohibitions on the consumption of pork and the limited extent of pig farming across much of this region, however, suggest that many reported taeniosis cases are likely to be attributable to T. saginata rather than Taenia solium or Taenia asiatica. There was a paucity of data regarding both the prevalence and economic impact of bovine cysticercosis. More detailed epidemiological data on both T. saginata taeniosis and bovine cysticercosis could be obtained by adopting an integrated "One Health" approach, considering the characteristics (e.g. ecosystem related and sociopolitical aspects) of the MENA region. Compared with more conventional approaches, this could lead to an enhanced performance and cost-effectiveness of surveillance systems.

Effects of inequality of supply hours on consumers' coping strategies and perceptions of intermittent water supply in Kathmandu Valley, Nepal

To investigate the effects of unequal supply hours on consumers' coping strategies and perceptions of the intermittent water supply (IWS) in the Kathmandu Valley (KV), Nepal we conducted a randomized household survey (n=369) and on-site water quality tests. Half of the households received piped water for 6 or fewer hours per week. To augment or cope with the inadequate supply, 28% of the households used highly contaminated and expensive tanker-delivered water. Half of the piped water samples (n=13) were contaminated with Escherichia coli. Free chlorine concentration in all piped water samples was below the national standards (0.1-0.2mg/L), but combined chlorine was detected at an average of 0.24mg/L, indicating ingression of contaminants in the network. Point-of-use devices could increase access to safe water in the KV from 42% to 80%. The use of Lorenz curves and Gini coefficients revealed inequality of piped water supply hours per week both between and within service areas in the KV, due mainly to a small percentage of households who receive longer supply hours. To cope with reduced supply hours, home owners pay more to get water from alternative sources, while tenants compromise their water consumption. Under IWS, expectations for improvements in piped water quality and supply regularity are higher than those for supply volume. Consumers' perceptions of the piped water services worsen with the reduction in supply hours, but perceptions of piped water tariff are independent of supply hours.

Effects of Boiling Drinking Water on Diarrhea and Pathogen-Specific Infections in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

Globally, approximately 2 billion people lack microbiologically safe drinking water. Boiling is the most prevalent household water treatment method, yet evidence of its health impact is limited. To conduct this systematic review, we searched four online databases with no limitations on language or publication date. Studies were eligible if health outcomes were measured for participants who reported consuming boiled and untreated water. We used reported and calculated odds ratios (ORs) and random-effects meta-analysis to estimate pathogen-specific and pooled effects by organism group and nonspecific diarrhea. Heterogeneity and publication bias were assessed using I2, meta-regression, and funnel plots; study quality was also assessed. Of the 1,998 records identified, 27 met inclusion criteria and reported extractable data. We found evidence of a significant protective effect of boiling for Vibrio cholerae infections (OR = 0.31, 95% confidence interval [CI] = 0.13-0.79, N = 4 studies), Blastocystis (OR = 0.35, 95% CI = 0.17-0.69, N = 3), protozoal infections overall (pooled OR = 0.61, 95% CI = 0.43-0.86, N = 11), viral infections overall (pooled OR = 0.83, 95% CI = 0.7-0.98, N = 4), and nonspecific diarrheal outcomes (OR = 0.58, 95% CI = 0.45-0.77, N = 7). We found no evidence of a protective effect for helminthic infections. Although our study was limited by the use of self-reported boiling and non-experimental designs, the evidence suggests that boiling provides measureable health benefits for pathogens whose transmission routes are primarily water based. Consequently, we believe a randomized controlled trial of boiling adherence and health outcomes is needed.

Management of rainwater harvesting and its impact on the health of people in the Middle East: case study from Yatta town, Palestine

Water-related diseases are a primary problem in Palestine where many residents revert to harvested rainwater as their primary water source due to water shortages within the area. From an environmental engineering perspective, it is already well known that certain situations (e.g., cross contamination) reduce drinking water quality and ultimately cause diseases in a population. In this study, we investigated the social practices and situations that may lead to lower disease occurrence. Towards this goal, we surveyed 382 residents in Yatta to collect data on the water-related diseases that they experienced and the specific situations that might affect the disease occurrences such as the residents' practices (i) for maintaining a high quality of cistern water, (ii) for maintaining the environment around the cistern, and (iii) for managing the wastewater. In addition, we measured the physicochemical and microbiological parameters in cisterns to support the qualitative survey data. The measured parameters, including turbidity, salinity, free available chlorine, total Coliforms, and fecal Coliforms, were above Palestinian Standard Institution (PSI) and World Health Organization (WHO) guideline levels, suggesting a potential infectious hazard. The poor quality of the water was also observed by residents based on change in taste and by visually noting floating impurities, turbidity, and green coloration. Survey results showed that observations of the poor quality in cisterns and surrounding environment had statistically significant correlation with most of the water-related diseases. Additionally, frequently emptying the septic tank contributes to improving the observed water qualities. Therefore, residents should be encouraged to continue to observe the water quality in the cistern, improve the surrounding environment of cistern, and empty their septic tank frequently, to keep the water diseases away from their households.

An insight into the drinking-water access in the health institutions at the Saharawi refugee camps in Tindouf (Algeria) after 40years of conflict

Drinking water access in the Saharawi refugee camps located in the Algerian desert is a challenge that is still an on-going problem after 40years of conflict. This work presents an analysis of the situation with emphasis on the water supply in health institutions (quantity and quality) including both sanitary inspections and a comprehensive water quality study. Results from sanitary inspections show that only half of the water supply installations at the hospitals are in adequate conditions and the rest present high risk of microbiological contamination. Water access in small medical community centres on the other hand present issues related to the non-availability of food-grade water tanks for the institutions (70%), the use of small 10l containers as the main water supply (40%), poor maintenance (60% under antihygienic conditions and 30% with damaged covers), and insufficient chlorine levels that prevent microbiological contamination. Regarding water quality analyses, raw water supply in Smara, El Aiun and Awserd camps present high conductivity and high levels of fluoride, chloride, nitrate and sulphate, but dropping to normal levels within the drinking-water standards after water treatment via reverse osmosis plants. But for the case of El Aiun and Awserd, the reverse osmosis plant only provides treated water to the population each 20days, so the population receives raw water directly and health risks should be evaluated. Finally, Dakhla water supply is the best in terms of physico-chemical parameters quality, currently providing safe drinking water after a chlorination stage. In summary, drinking water access has improved dramatically in the last years due to the efforts of local and international authorities but several issues remain to be solved: access to treated water for all the population, improved water quality controls (especially in Dakhla), expansion of distribution networks, and adequate storage systems and maintenance.

Sanitary impact evaluation of drinking water in storage reservoirs in Moroccan rural area

In Morocco, storage reservoirs are particular systems of water supply in rural areas. These reservoirs are fed with rainwater and/or directly from the river, which are very contaminated by several pathogenic bacteria. They are used without any treatment as a drinking water by the surrounding population. In this context, the aim of this study is to evaluate the impact of consuming contaminated water stored in reservoirs on health status for six rural communities located in Assif El Mal, Southern East of Marrakech. This was investigated using a classical methodology based on population survey and by molecular approach using PCR–DGGE technique to determine the intestinal bacterial diversity of consumers. The survey showed that, the residents of the studied area suffered from numerous health problems (diarrheal diseases, vomiting or hepatitis A) due to the lack of waste management infrastructures. The consumer’s stool analysis by molecular approach revealed that numbers of Escherichia coli, Aeromonas hydrophila and Clostridia, were significantly higher in the diarrheal feces. In addition, PCR–DGGE study of the prevalence and distribution of bacteria causing human diseases, confirmed that, there is a relationship between water bacterial contaminations of storage reservoirs and microbial disease related health status. Therefore, water reservoir consumption is assumed to be the mean way of exposure for this population.

It’s clear that this approach gives a very helpful tool to confirm without any doubt the relationship between water bacterial contamination and health status.

Contamination of Hospital Water Supplies in Gilan, Iran, with Legionella pneumophila, Escherichia coli, and Pseudomonas aeruginosa

This study is designed to determine the contamination degree of hospital water supplies with Pseudomonas aeruginosa, Legionella pneumophila, and E. coli in Gilan, Iran. Samples were collected directly into sterile containers and concentrated by centrifuge. Half part of any sample transferred to yeast extract broth and the second part transferred to Trypticase Soy Broth and incubated for 3 days. DNA was extracted by using commercial kit. Four rounds of PCR were performed as follows: multiplex PCR for detecting Pseudomonas aeruginosa, Integron 1, and Metallo-β-lactamases gene; PCR for detecting Legionella pneumophila and mip gene separately; PCR for detecting E. coli; and another PCR for detecting whole bacterial presence. Contamination rates of cold, warm, and incubator water samples with P. aeruginosa, were 16.6%, 37.5%, and 6.8% consequently. Degrees of contamination with L. pneumophila were 3.3%, 9.3%, and 10.9% and with E. coli were zero, 6.2%, and zero. Total bacterial contamination of cold, warm, and incubator water samples was 93.3%, 84.4%, and 89.0% consequently. Metallo-β-lactamases gene was found in 20.0% of all samples. Contamination degree with P. aeruginosa was considerable and with L. pneumophila was moderate. Metallo-β-lactamases gene was found frequently indicating widespread multiple drug resistance bacteria. We suggest using new decontamination method based on nanotechnology.

Upgrading a piped water supply from intermittent to continuous delivery and association with waterborne illness: a matched cohort study in urban India

BACKGROUND

Intermittent delivery of piped water can lead to waterborne illness through contamination in the pipelines or during household storage, use of unsafe water sources during intermittencies, and limited water availability for hygiene. We assessed the association between continuous versus intermittent water supply and waterborne diseases, child mortality, and weight for age in Hubli-Dharwad, India.

METHODS AND FINDINGS

We conducted a matched cohort study with multivariate matching to identify intermittent and continuous supply areas with comparable characteristics in Hubli-Dharwad. We followed 3,922 households in 16 neighborhoods with children <5 y old, with four longitudinal visits over 15 mo (Nov 2010-Feb 2012) to record caregiver-reported health outcomes (diarrhea, highly credible gastrointestinal illness, bloody diarrhea, typhoid fever, cholera, hepatitis, and deaths of children <2 y old) and, at the final visit, to measure weight for age for children <5 y old. We also collected caregiver-reported data on negative control outcomes (cough/cold and scrapes/bruises) to assess potential bias from residual confounding or differential measurement error. Continuous supply had no significant overall association with diarrhea (prevalence ratio [PR] = 0.93, 95% confidence interval [CI]: 0.83-1.04, p = 0.19), bloody diarrhea (PR = 0.78, 95% CI: 0.60-1.01, p = 0.06), or weight-for-age z-scores (Δz = 0.01, 95% CI: -0.07-0.09, p = 0.79) in children <5 y old. In prespecified subgroup analyses by socioeconomic status, children <5 y old in lower-income continuous supply households had 37% lower prevalence of bloody diarrhea (PR = 0.63, 95% CI: 0.46-0.87, p-value for interaction = 0.03) than lower-income intermittent supply households; in higher-income households, there was no significant association between continuous versus intermittent supply and child diarrheal illnesses. Continuous supply areas also had 42% fewer households with ≥1 reported case of typhoid fever (cumulative incidence ratio [CIR] = 0.58, 95% CI: 0.41-0.78, p = 0.001) than intermittent supply areas. There was no significant association with hepatitis, cholera, or mortality of children <2 y old; however, our results were indicative of lower mortality of children <2 y old (CIR = 0.51, 95% CI: 0.22-1.07, p = 0.10) in continuous supply areas. The major limitations of our study were the potential for unmeasured confounding given the observational design and measurement bias from differential reporting of health symptoms given the nonblinded treatment. However, there was no significant difference in the prevalence of the negative control outcomes between study groups that would suggest undetected confounding or measurement bias.

CONCLUSIONS

Continuous water supply had no significant overall association with diarrheal disease or ponderal growth in children <5 y old in Hubli-Dharwad; this might be due to point-of-use water contamination from continuing household storage and exposure to diarrheagenic pathogens through nonwaterborne routes. Continuous supply was associated with lower prevalence of dysentery in children in low-income households and lower typhoid fever incidence, suggesting that intermittently operated piped water systems are a significant transmission mechanism for Salmonella typhi and dysentery-causing pathogens in this urban population, despite centralized water treatment. Continuous supply was associated with reduced transmission, especially in the poorer higher-risk segments of the population.

Seasonal variation of fecal contamination in drinking water sources in developing countries: a systematic review

Accounting for fecal contamination of drinking water sources is an important step in improving monitoring of global access to safe drinking water. Fecal contamination varies with time while its monitoring is often infrequent. We sought to understand seasonal trends in fecal contamination to guide best practices to capture seasonal variation and ascertain the extent to which the results of a single sample may overestimate compliance with health guidelines. The findings from 22 studies from developing countries written in English and identified through a systematic review were analyzed. Fecal contamination in improved drinking water sources was shown to follow a statistically significant seasonal trend of greater contamination during the wet season (p<0.001). This trend was consistent across fecal indicator bacteria, five source types, twelve Köppen-Geiger climate zones, and across both rural and urban areas. Guidance on seasonally representative water quality monitoring by the World Health Organization and national water quality agencies could lead to improved assessments of access to safe drinking water.

Tropical soils with high aluminum concentrations cause oxidative stress in two tomato genotypes

Tropical and subtropical soils are usually acidic and have high concentrations of aluminum (Al). Aluminum toxicity in plants is caused by the high affinity of the Al cation for cell walls, membranes, and metabolites. In this study, the response of the antioxidant-enzymatic system to Al was examined in two tomato genotypes: Solanum lycopersicum var. esculentum (Calabash Rouge) and Solanum lycopersicum var. cerasiforme (CNPH 0082) grown in tropical soils with varying levels of Al. Plant growth; activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPOX), and glutathione reductase (GR) enzymes; stress-indicating compounds (malondialdehyde (MDA) and hydrogen peroxide); and morphology (root length and surface area) were analyzed. Increased levels of Al in soils were correlated with reduced shoot and root biomass and with reduced root length and surface area. Calabash Rouge exhibited low Al concentrations and increased growth in soils with the highest levels of Al. Plants grown in soils with high availability of Al exhibited higher levels of stress indicators (MDA and hydrogen peroxide) and higher enzyme activity (CAT, APX, GPOX, and GR). Calabash Rouge absorbed less Al from soils than CNPH 0082, which suggests that the genotype may possess mechanisms for Al tolerance.

Water distribution system deficiencies and gastrointestinal illness: a systematic review and meta-analysis

BACKGROUND

Water distribution systems are vulnerable to performance deficiencies that can cause (re)contamination of treated water and plausibly lead to increased risk of gastrointestinal illness (GII) in consumers.

OBJECTIVES

It is well established that large system disruptions in piped water networks can cause GII outbreaks. We hypothesized that routine network problems can also contribute to background levels of waterborne illness and conducted a systematic review and meta-analysis to assess the impact of distribution system deficiencies on endemic GII.

METHODS

We reviewed published studies that compared direct tap water consumption to consumption of tap water re-treated at the point of use (POU) and studies of specific system deficiencies such as breach of physical or hydraulic pipe integrity and lack of disinfectant residual.

RESULTS

In settings with network malfunction, consumers of tap water versus POU-treated water had increased GII [incidence density ratio (IDR) = 1.34; 95% CI: 1.00, 1.79]. The subset of nonblinded studies showed a significant association between GII and tap water versus POU-treated water consumption (IDR = 1.52; 95% CI: 1.05, 2.20), but there was no association based on studies that blinded participants to their POU water treatment status (IDR = 0.98; 95% CI: 0.90, 1.08). Among studies focusing on specific network deficiencies, GII was associated with temporary water outages (relative risk = 3.26; 95% CI: 1.48, 7.19) as well as chronic outages in intermittently operated distribution systems (odds ratio = 1.61; 95% CI: 1.26, 2.07).

CONCLUSIONS

Tap water consumption is associated with GII in malfunctioning distribution networks. System deficiencies such as water outages also are associated with increased GII, suggesting a potential health risk for consumers served by piped water networks.

Fecal contamination of drinking-water in low- and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Access to safe drinking-water is a fundamental requirement for good health and is also a human right. Global access to safe drinking-water is monitored by WHO and UNICEF using as an indicator "use of an improved source," which does not account for water quality measurements. Our objectives were to determine whether water from "improved" sources is less likely to contain fecal contamination than "unimproved" sources and to assess the extent to which contamination varies by source type and setting.

METHODS AND FINDINGS

Studies in Chinese, English, French, Portuguese, and Spanish were identified from online databases, including PubMed and Web of Science, and grey literature. Studies in low- and middle-income countries published between 1990 and August 2013 that assessed drinking-water for the presence of Escherichia coli or thermotolerant coliforms (TTC) were included provided they associated results with a particular source type. In total 319 studies were included, reporting on 96,737 water samples. The odds of contamination within a given study were considerably lower for "improved" sources than "unimproved" sources (odds ratio [OR] = 0.15 [0.10-0.21], I2 = 80.3% [72.9-85.6]). However over a quarter of samples from improved sources contained fecal contamination in 38% of 191 studies. Water sources in low-income countries (OR = 2.37 [1.52-3.71]; p<0.001) and rural areas (OR = 2.37 [1.47-3.81] p<0.001) were more likely to be contaminated. Studies rarely reported stored water quality or sanitary risks and few achieved robust random selection. Safety may be overestimated due to infrequent water sampling and deterioration in quality prior to consumption.

CONCLUSION

Access to an "improved source" provides a measure of sanitary protection but does not ensure water is free of fecal contamination nor is it consistent between source types or settings. International estimates therefore greatly overstate use of safe drinking-water and do not fully reflect disparities in access. An enhanced monitoring strategy would combine indicators of sanitary protection with measures of water quality.

Comparing microbial water quality in an intermittent and continuous piped water supply

Supplying piped water intermittently is a common practice throughout the world that increases the risk of microbial contamination through multiple mechanisms. Converting an intermittent supply to a continuous supply has the potential to improve the quality of water delivered to consumers. To understand the effects of this upgrade on water quality, we tested samples from reservoirs, consumer taps, and drinking water provided by households (e.g. from storage containers) from an intermittent and continuous supply in Hubli-Dharwad, India, over one year. Water samples were tested for total coliform, Escherichia coli, turbidity, free chlorine, and combined chlorine. While water quality was similar at service reservoirs supplying the continuous and intermittent sections of the network, indicator bacteria were detected more frequently and at higher concentrations in samples from taps supplied intermittently compared to those supplied continuously (p < 0.01). Detection of E. coli was rare in continuous supply, with 0.7% of tap samples positive compared to 31.7% of intermittent water supply tap samples positive for E. coli. In samples from both continuously and intermittently supplied taps, higher concentrations of total coliform were measured after rainfall events. While source water quality declined slightly during the rainy season, only tap water from intermittent supply had significantly more indicator bacteria throughout the rainy season compared to the dry season. Drinking water samples provided by households in both continuous and intermittent supplies had higher concentrations of indicator bacteria than samples collected directly from taps. Most households with continuous supply continued to store water for drinking, resulting in re-contamination, which may reduce the benefits to water quality of converting to continuous supply.

The performance of Electro-Fenton oxidation in the removal of coliform bacteria from landfill leachate

Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an effective solution to this problem. The technology that can be used may differ based on the type of leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The study focused on two types of leachate: Palau Borung landfill leachate with low Coliform content (200 MPN/100 m/L) and Ampang Jajar landfill leachate with high coliform content (>24 × 10(4)MPN/100 m/L). Optimal conditions for the Electro-Fenton treatment process were applied on both types of leachate. Then, the coliform was examined before and after treatment using the Most Probable Number (MPN) technique. Accordingly, 100% removal of coliform was obtained at low initial coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate.

Groundwater contaminations and health perspectives in developing world case study: Gaza Strip

Groundwater is the only source of water in the Gaza Strip. The results of a 10-year monitoring program revealed that more than 90% of the available water is not suitable for drinking purposes as a result of elevated chemical contaminants as well as microbiological organisms. The archives of the local hospitals showed catastrophic records on diseases caused by water directly and indirectly. Methemoglobinemia and dental fluorosis are well-known diseases caused by elevated nitrate and fluoride, respectively. Water-borne diseases are currently high and will increase if water, sanitation, and food-control services are not restored, or are allowed to deteriorate further. Heavy use and misuse of banned and prohibited pesticides may show other hard diseases in the near future. Geography, politics, and war combine to make the Gaza Strip a worst-case scenario for water-resource planners. Urgent alternative water resources should be secured and the human health should be given the highest priority.

Assessing the public health risk of microbial intrusion events in distribution systems: conceptual model, available data, and challenges

Low and negative pressure events in drinking water distribution systems have the potential to result in intrusion of pathogenic microorganisms if an external source of contamination is present (e.g., nearby leaking sewer main) and there is a pathway for contaminant entry (e.g., leaks in drinking water main). While the public health risk associated with such events is not well understood, quantitative microbial risk assessment can be used to estimate such risk. A conceptual model is provided and the state of knowledge, current assumptions, and challenges associated with the conceptual model parameters are presented. This review provides a characterization of the causes, magnitudes, durations and frequencies of low/negative pressure events; pathways for pathogen entry; pathogen occurrence in external sources of contamination; volumes of water that may enter through the different pathways; fate and transport of pathogens from the pathways of entry to customer taps; pathogen exposure to populations consuming the drinking water; and risk associated with pathogen exposure.

Cholinesterase activity, pesticide exposure and health impact in a population exposed to organophosphates

OBJECTIVE

Biological monitoring is an essential component for assessing the exposure of individuals to organophosphate pesticides. The aim of this study was to determine cholinesterase activity, pesticide exposure and health effects in the exposed population.

METHODS

A total of 90 individuals occupationally exposed to OPs and 30 controls were recruited in this study. Erythrocyte acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities were measured in two periods of low- and high-exposure.

RESULTS

There were statistically significant decrease in AChE and BuChE activities in the high-exposure period (20.73 +/- 0.99 U/gHb and 3.73 +/- 0.19 U/mL, respectively, P < 0.001) compared to the low-exposure period (29.81 +/- 1.19 U/gHb and 4.92 +/- 0.19 U/mL, respectively). All enzyme activities in the exposed group were statistically lower than in the control group. Analysis of the relation between cholinesterase activity and symptoms showed significant evidences.

CONCLUSIONS

The results suggested the association between occupational pesticide exposure and inhibition of cholinesterases. Thus, medical monitoring of cholinesterase inhibition and intervention programs regarding safety practices during field work are important issues aimed at minimizing adverse health effects of pesticide.