Quantifying tap-to-household water quality deterioration in urban communities in Vellore, India: The impact of spatial assumptions

Fecal Indicator Bacteria Data to Characterize Drinking Water Quality in Low-Resource Settings: Summary of Current Practices and Recommendations for Improving Validity

Fecal indicator bacteria (FIB) values are widely used to assess microbial contamination in drinking water and to advance the modeling of infectious disease risks. The membrane filtration (MF) testing technique for FIB is widely adapted for use in low- and middle-income countries (LMICs). We conducted a systematic literature review on the use of MF-based FIB data in LMICs and summarized statistical methods from 172 articles. We then applied the commonly used statistical methods from the review on publicly available datasets to illustrate how data analysis methods affect FIB results and interpretation. Our findings indicate that standard methods for processing samples are not widely reported, the selection of statistical tests is rarely justified, and, depending on the application, statistical methods can change risk perception and present misleading results. These results raise concerns about the validity of FIB data collection, analysis, and presentation in LMICs. To improve evidence quality, we propose a FIB data reporting checklist to use as a reminder for researchers and practitioners.

Water quality, sanitation, and hygiene among the tribal community residing in Jawadhi hills, Tamilnadu: An observational study from Southern India

Objectives:

To assess the water, sanitation, and hygiene (WASH) practice among the tribal population of Tamil Nadu, India and to determine the physiochemical and bacteriological quality of drinking water at the principal source and at the households along with the household-level determinants of WASH practices.

Methods:

A door-to-door survey was conducted in 150 households, distributed across six villages of Jawadhi hills, a tribal area in the state of Tamil Nadu, India. Water samples were collected from the principal sources and a subset of households for assessing water quality. A composite scoring was formulated to determine the overall WASH practices.

Results:

Overall, a poor WASH score (≤4) was found in 103 (68.7%; 95% CI: 60.7, 75.6) households. The majority (96.7%) of the household water samples showed the presence of fecal coliforms. Poor WASH score was uniformly distributed across the villages. Low per capita income (≤1000 INR) was strongly associated with the poor WASH score (Adjusted OR 2.4; 95% CI: 1.04, 5.7). The per capita income had a strong negative association with the high fecal coliform count (Adjusted OR 5.07; 95% CI: 1.08, 23.74).

Conclusions:

We conclude that WASH-related practices among the tribal population of Tamil Nadu is not acceptable. The lack of administrative function and poor economic conditions are the likely causes attributed to the poor WASH conditions and drinking water quality. Urgent action from the stakeholders is the need of the hour to improve the water quality and living standards of such marginalized populations.

Drinking Water Safety: Role of Hand Hygiene, Sanitation Facility, and Water System in Semi-Urban Areas of India

Poor drinking water quality is one of the main causes of acute diarrheal disease in developing countries. The study investigated the relationship between fecal contamination of hands, stored drinking water, and source waters in India. We further evaluated the environmental and behavioral factors associated with recontamination of water between collection and consumption. The bacterial contamination, that is, Escherichia coli (log₁₀ most probable number per two hands), found on mothers' hands (mean = 1.11, standard deviation [SD] = 1.2, N = 152) was substantially higher than that on their children younger than 5 years (mean = 0.64, SD = 1.0, and N = 152). We found a low level of E. coli (< 1 per 100 mL) in the source water samples; however, E. coli contamination in stored drinking water was above the recommended guidelines of the World Health Organization. The study also found that E. coli on hands was significantly associated with E. coli in the stored drinking water (P < 0.001). Moreover, E. coli was positively associated with gastrointestinal symptoms (odds ratio 1.42, P < 0.05). In the households with elevated levels (> 100 E. coli/100 mL) of fecal contamination, we found that 43.5% had unimproved sanitation facilities, poor water handling practices, and higher diarrheal incidences. The water quality deterioration from the source to the point of consumption is significant. This necessitates effective interventions in collection, transport, storage, and extraction practices when hand-water contact is likely to occur. These findings support the role of hands in the contamination of stored drinking water and suggest that clean source water does not guarantee safe water at the point of consumption.

Understanding the impacts of intermittent supply on the drinking water microbiome

Increasing access to piped water in low-income and middle-income countries combined with the many factors that threaten our drinking water supply infrastructure mean that intermittent water supply (IWS) will remain a common practice around the world. Common features of IWS include water stagnation, pipe drainage, intrusion, backflow, first flush events, and household storage. IWS has been shown to cause degradation as measured by traditional microbial water quality indicators. In this review, we build on new insights into the microbial ecology of continuous water supply systems revealed by sequencing methods to speculate about how intermittent supply conditions may further influence the drinking water microbiome, and identify priorities for future research.

Impact of wastewater-irrigation on in-household water contamination. A cohort study among urban farmers in Ahmedabad, India

This cohort study explores the contribution of wastewater irrigation, in the context of WASH (Water, Sanitation, Hygiene), on in-household water contamination among urban farming households in Ahmedabad, India. Drinking water samples of 204 households in four peri-urban farming communities were collected from the point-of-source (PoS) and point-of-use (PoU) of each household four times over the 12-month follow-up period. Next to the quantification of E. coli, three household surveys (baseline, hygiene and farm) were conducted. Additionally, an observational spot-check was undertaken in bi-monthly intervals throughout the follow-up period. Significant positive differences in water quality between PoS and PoU samples were identified in 78% of households. During the monsoon, the peak of contamination, only 6% of households had access to safe drinking water at PoU. The Average Treatment Effect (ATE) of wastewater irrigation indicates an adverse effect on in-household water contamination, larger in effect size than the mitigation effect of access to sanitation or personal hygiene. To control transmission of fecal pathogens, effective barriers are required for wastewater irrigation similar to the necessity of ensuring access to sanitation and practicing adequate hygiene behavior.

Physicochemical parameters affecting the perception of borehole water quality in Ghana

Rural Ghanaian communities continue using microbiologically contaminated surface water sources due in part to undesirable organoleptic characteristics of groundwater from boreholes. Our objective was to identify thresholds of physical and chemical parameters associated with consumer complaints related to groundwater. Water samples from 94 boreholes in the dry season and 68 boreholes in the rainy season were analyzed for 18 parameters. Interviews of consumers were conducted at each borehole regarding five commonly expressed water quality problems (salty taste, presence of particles, unfavorable scent, oily sheen formation on the water surface, and staining of starchy foods during cooking). Threshold levels of water quality parameters predictive of complaints were determined using the Youden index maximizing the sum of sensitivity and specificity. The probability of complaints at various parameter concentrations was estimated using logistic regression. Exceedances of WHO guidelines were detected for pH, turbidity, chloride, iron, and manganese. Concentrations of total dissolved solids (TDS) above 172mg/L were associated with salty taste complaints. Although the WHO guideline is 1000mg/L, even at half the guideline, the likelihood of salty taste complaint was 75%. Iron concentrations above 0.11, 0.14 and 0.43mg/L (WHO guideline value 0.3mg/L) were associated with complaints of unfavorable scent, oily sheen, and food staining, respectively. Iron and TDS concentrations exhibited strong spatial clustering associated with specific geological formations. Improved groundwater sources in rural African communities that technically meet WHO water quality guidelines may be underutilized in preference of unimproved sources for drinking and domestic uses, compromising human health and sustainability of improved water infrastructure.