Bacterial Contamination of Drinking Water in Guadalajara, Mexico

Study on the inactivation effect and mechanism of EGCG disinfectant on Bacillus subtilis

The widespread use of chlorine-based disinfectants in drinking water treatment has led to the proliferation of chlorine-resistant bacteria and the risk of disinfection byproducts (DBPs), posing a serious threat to public health. This study aims to explore the effectiveness and potential applications of epigallocatechin gallate (EGCG) against chlorine-resistant Bacillus and its spores in water, providing new insights for the control of chlorine-resistant bacteria and improving the biological stability of distribution systems. The inactivation effects of EGCG on Bacillus subtilis (B. subtilis) and its spores were investigated using transmission electron microscopy, ATP measurement, and transcriptome sequencing analysis to determine changes in surface structure, energy metabolism, and gene expression levels, thereby elucidating the inactivation mechanism. The results demonstrate the potential application of EGCG in continuously inhibiting chlorine-resistant B. subtilis in water, effectively improving the biological stability of the distribution system. However, EGCG is not suitable for treating raw water with high spore content and is more suitable as a supplementary disinfectant for processes with strong spore removal capabilities, such as ozone, ultraviolet, or ultrafiltration. EGCG exhibits a disruptive effect on the morphological structure and energy metabolism of B. subtilis and suppresses the synthesis of substances, energy metabolism, and normal operation of the antioxidant system by inhibiting the expression of multiple genes, thereby achieving the inactivation of B. subtilis.

Water quality and phenotypic antimicrobial resistance in isolated of E. coli from water for human consumption in Bagua, under One Health approach

The One Health approach acknowledges the interconnection between human health, animal health, and environmental health, recognizing that these domains are closely intertwined, as many diseases affecting humans are also common in animals. Water acts as a vehicle for the transmission of such diseases, highlighting the significance of monitoring the quality of water intended for human consumption. In 2022, a research study was conducted to evaluate the water quality for human consumption in Bagua, Amazonas Region. The physicochemical analysis indicated that most parameters were within normal range, except for residual chlorine, which was predominantly absent. Microbiological analysis revealed the presence of total coliforms and E. coli. Phenotypic characterization of E. coli isolates exhibited resistance to the several antibiotics, including nalidixic acid, gentamicin, amoxicillin plus clavulanic acid, norfloxacin, and ciprofloxacin. These findings indicate a compromised production of water for human consumption, as per the water quality regulations in Peru. The presence of fecal contamination poses a significant microbiological risk to consumers. These results underscore the breakdown of the human-environment-animal interface within the One Health approach, thereby endangering public health.

Quality Control of Drinking Water in the City of Ilave, Region of Puno, Peru

The region of Puno, in Peru, is described as a region with some health conditions that may be associated with the water quality, such as a high index of anemia or cases of acute diarrhea in children. This study aimed at monitoring the drinking water quality of the city of Ilave, in Peru, and determining possible correlations between physical-chemical and microbiological parameters, and the water distribution conditions, such as the period of water availability. Physical-chemical parameters (turbidity, residual chlorine, temperature, conductivity, and pH), microbiological parameters (presence of coliforms), and heavy metals (Zn, Mn, Ni, Fe, and Cu) were determined. All the parameters quantified were within the maximum permissible limits according to Peruvian regulations, except for residual chlorine, which was, for all the treated water samples, below the recommended value of 0.5 mg/L. Coliforms that should be absent from drinking water were detected in all the household samples. These results demonstrate the need for the inclusion of additional steps of re-chlorination along the distribution system to guarantee the maintenance of residual levels of chlorine that assure the microbiological quality of water. The quality of the drinking water was not observed to correlate with the period of water availability.

Chlorination for low-cost household water disinfection - A critical review and status in three Latin American countries

Chlorination has historically provided microbiologically safe drinking water in public water supplies. Likewise, chlorine has also been introduced as a low-cost disinfection method in rural and marginalized communities, both at community and household level, as well as during emergencies. Although this practice is common and well established for use as a household water treatment technology in the Global South, several challenges in effective and efficient implementation still need to be addressed. Here, we explored these issues by a literature review and narrowed them to the status of three Latin American countries (Mexico, Colombia, and Brazil). Overall, it was found that although guidance on household-based chlorination includes information on health risks and hygiene, this may not create enough incentive for the user to adapt the method satisfactorily. Physicochemical quality of the water influences chlorination efficiency and it is found that variations in quality are rarely considered when recommending chlorine doses during implementation. These are far more often based on a few measurements of turbidity, thereby not considering dissolved organic matter, or seasonal and day-to-day variations. Other factors such as user preferences, chlorine product quality and availability also represent potential barriers to the sustainable use of chlorination. For chlorination to become a sustainable household water treatment, more focus should therefore be given to local conditions prior to the intervention, as well as support and maintenance of behavioural changes during and after the intervention.

Bacteriological Quality of Drinking Water and Hygienic Assessment of Water Cooler Dispensers in Higher Education Institution

Background

The bacteriological quality of drinking water has become a public health concern according to its association with water-borne diseases. Nowadays, there are several different types of drinking water, including water cooler dispensers (WCDs), which are becoming a popular device in educational institutions. Therefore, this study aims to determine the bacteriological quality of drinking water from WCDs, and inspect their hygienic conditions in students' dormitories at a university in Nakhon Si Thammarat, Thailand.

Methods

Water samples from 53 WCDs installed in 13 dormitories were collected and analyzed coliform bacteria by using the multiple-tube fermentation technique. The hygienic inspection form from the Department of Health, Ministry of Public Health, was used for inspection of the sanitary conditions. The hygienic factors of water cooler sanitation were analyzed using the generalized linear model.

Results

Coliform bacteria were found in 10 out of 53 samples; moreover, Escherichia coli was recovered in three samples. Maintenance/cleaning and monitoring were the most two sanitary issues found in 100% (53/53) of the WCDs. Location and features of machine were found the correlation with the prevalence of coliform bacteria in drinking water.

Conclusions

The findings of this study suggest regular monitoring of water quality in educational institutions. Also, the Sanitary Standard and Operational Procedures (S.S.O.P.) should be developed to improve the hygienic conditions of the water cooler dispensers.

Global water shortage and potable water safety; Today's concern and tomorrow's crisis

Climate change, severe droughts, population growth, demand increase, and poor management during the recent decades have further stressed the scarce freshwater resources worldwide and resulted in severe water shortages in many regions. The water utilities address the water shortage by providing alternative source of water, augment the supplied water, supply intermittently, and even bulk water delivery under severe water shortage conditions. On the other hand, many households store water in building storage tanks to cope with insufficient delivery of potable water due to frequent interruptions. All these practices could pose crucial risks to the chemical and microbiological quality of the water. However, consistent monitoring and implementation of mitigation strategies could lower the potential risks associated with these practices. It is critical to identify the potential hazards resulting from the alternative water supplies and distribution practices to develop temporary and long-term monitoring and mitigation plans and reduce the microbial and chemical contamination of potable water delivered to the consumers. This paper provides a holistic review of the significant hazards associated with the practices employed by the water utilities and water consumers to alleviate the potable water shortage and discusses the required monitoring and mitigation practices.

Microbial water quality improvement associated with transitioning from intermittent to continuous water supply in Nagpur, India

Nearly half a billion people living in Indian cities receive their drinking water from an intermittent water supply (IWS), which can be associated with degraded water quality and risk of waterborne disease. The municipal water supply in Nagpur, India is transitioning from intermittent to continuous supply in phases. We conducted cross-sectional sampling to compare microbial water quality under IWS and continuous water supply (CWS) in Nagpur. In 2015 and 2017, we collected 146 grab samples and 90 large-volume dead-end ultrafiltration (DEUF) samples (total volume: 6,925 liters). In addition to measuring traditional water quality parameters, we also assayed DEUF samples by droplet digital PCR (ddPCR) for waterborne pathogen gene targets. At household taps served by IWS, we detected targets from enterotoxigenic E. coli, Shigella spp./enteroinvasive E. coli, norovirus GI and GII, adenovirus A-F, Cryptosporidium spp., and Giardia duodenalis. We observed a significant increase in the proportion of grab samples positive for culturable E. coli (p = 0.0007) and DEUF concentrates positive for waterborne pathogen gene targets (p = 0.0098) at household taps served by IWS compared to those served by CWS. IWS continues to be associated with fecal contamination, and, in this study, with increased prevalence of molecular evidence of waterborne pathogens. These findings add mounting evidence that, despite the presence of piped on premise infrastructure, IWS is less likely to meet the requirements for safely-managed drinking water as defined by the Sustainable Development Goals. Importantly, these findings demonstrate the transition from IWS to CWS in Nagpur is yielding meaningful improvements in microbial water quality.

Lack of Safe Drinking Water for Lake Chapala Basin Communities in Mexico Inhibits Progress toward Sustainable Development Goals 3 and 6

BACKGROUND

Access to safe, affordable and accessible drinking water is a human right and foundational to the third and sixth World Health Organization's Sustainable Development Goals (SDGs). Unsafe drinking water is a risk factor for chronic and enteric diseases. Both chronic kidney disease (CKD) and diarrheal disease are highly prevalent in the Lake Chapala basin, Jalisco, Mexico, suggesting disparities in factors leading to successful achievement of these two SDGs.

METHODS

This study aimed to assess progress towards SDG three and six in the Lake Chapala basin. Qualitative, quantitative, and geospatial data were collected between May and August of 2019 from three towns within the municipalities of Poncitlán and Chapala.

RESULTS

Ninety-nine households participated in this study. Water sampling analyses determined 81.18% of samples from water jugs (garrafones) and 70.05% of samples from tap water were contaminated with total coliform bacteria, often including E. coli. Additionally, 32% of garrafón samples and 61.9% of tap water samples had detectable levels of arsenic. Approximately 97.94% of respondents stated that they believe clean water is a human right, but 78.57% feel the Mexican government does not do enough to make this a reality.

CONCLUSIONS

This mixed methods approach highlights water quality as a serious issue in communities around Lake Chapala, and demonstrates inadequate drinking water as a key hazard, potentially perpetuating the high disease burden of both CKD and enteric disease in the region.

Metals in Occluded Water: A New Perspective for Pollution in Drinking Water Distribution Systems

Occluded water is water that remains inside corrosion scales within deteriorating distribution pipes. The accumulation of iron and manganese in the occluded water is a potential risk for water quality. Thus, this study investigated the change in metal (iron, manganese, copper and chromium) concentration in occluded water, the effect of these metals on the flowing water, and the source of iron and manganese in the occluded water using a simulation device. The results showed that total iron and total manganese were enriched in the occluded water, while the concentrations of total copper and total chromium in the occluded water gradually decreased over time. The iron and manganese in the occluded water migrate to the flowing water causing pollution in the flowing water. Also, copper and chromium adsorb on the corrosion scales within the pipes. The iron and manganese in the occluded water mainly came from the corrosion of the metal pipes, and the corrosion scales had a certain obstructive effect on the outward migration of iron in the occluded water but had less hindrance to the migration of manganese. Occluded water plays a critical role in the pollution of drinking water, and additional work is needed to control metal accumulation and release.