In the sub-Saharan region of Africa, access to safe drinking water remains limited in many countries. This study provides an overview of the quality of surface water and groundwater in rural and peri-urban areas of Madagascar, Uganda, and Rwanda. Selected physico-chemical parameters, inorganic species (including inorganic ions), and organic pollution indicators, such as total organic carbon, non-ionic surfactants, cationic surfactants, anionic surfactants, sum of phenolic compounds and formaldehyde, were analysed. Principal component analysis was applied to assess the variability of the water quality and identify regional dependencies. The inorganic ion composition in the majority of the studied samples meets WHO and EU requirements for drinking water intended for human consumption and poses no human health risk. However, an individual non-cancer-causing health index for nitrates and the values of Water Quality Index show a possible threat of ingesting the studied drinking water. The presence of surfactants (0.1-0.65 mgL-1), phenolic compounds (0.025-1.76 mgL-1) and formaldehyde (0.04-0.32 mgL-1) may also pose a risk to human, animal, and aquatic life. Additionally, in-situ measurements for E. coli and Total Coliforms conducted during the last field campaign in Madagascar (2022) revealed that all studied drinking water sources ranged from intermediate risk to unsafe. This result calls for the urgent need to enhance WASH (water, sanitation, and hygiene) services in the studied areas. The presence of both chemical and microbiological pollutants shows the need for the local authorities to develop and implement a catchment management plan to ensure the protection of water resources from potential pollution, and raise community awareness about the impact of human activity on water resources.

BACKGROUND: Fluoride is an inorganic element, which can be found in high concentrations in groundwater. Its consumption and exposure have consequences on human health. The objective of this study was to evaluate fluoride exposure and develop a health risk assessment in children from an urban area with hydrofluorosis in Mexico.
METHODS: Water fluoride levels in active wells were provided by the Water State Agency and divided into three zones: agriculture zone (Zone A), metallurgical zone (Zone B), and industrial zone (Zone C). Urinary fluoride levels were determined by potentiometric method using an ion-selective electrode. Health risk assessment was performed through Monte Carlo model analysis and hazard quotient was calculated.
RESULTS: According to fluoride well concentration, all zones have high concentration especially Zone B (2.55 ± 0.98 mg/L). Urinary fluoride concentrations were highest in children in Zone B (1.42 ± 0.8 mg/L). The estimated median daily intake dose of fluoride was 0.084 mg/Kg-day for the children living in zone B. The highest mean HQ value was to Zone B (1.400 ± 0.980), followed by Zone C (0.626 ± 0.443).
CONCLUSIONS: The levels of fluoride exposure registered are a potential risk to generate adverse health effects in children in the San Luis Potosi metropolitan area.

Intermittent drinking water supply affects the health of over 300 million people globally. In Mozambique, it is largely practiced in cities and small towns. This results in frequent microbial contamination of the supplied drinking water posing a health risk to consumers. In Moamba, a small town in Southern Mozambique with 2,500 water connections, the impact of changes in operational strategies, namely increased chlorine dosage, increased supply duration and first-flush, on the microbial water quality was studied to determine best practices. To that aim, water quality monitoring was enhanced to provide sufficient data on the microbial contamination from 452 samples under the different strategies. The water at the outlet of the water treatment plant during all strategies was free of E. coli complying to the national standards. However, E. coli could be detected at household level. By increasing the chlorine dosage, the number of samples that showed E. coli absence increased at the two sampling locations in the distribution network: in Cimento from 72% to 83% and in Matadouro from 52% to 86%. Modifying the number and duration of supply cycles showed a different impact on the water quality at both locations in the distribution network. A positive effect was shown in Cimento, where the mean concentrations decreased slightly from 0.54 to 0.23 CFU/100 mL and 16.7 to 7.3 CFU/100 mL for E. coli and total coliforms respectively. The percentage of samples positive for bacteria was, however, similar. In contrast, a negative effect was shown in Matadouro where the percentage of positive samples increased and the mean bacterial concentrations increased slightly: E. coli from 0.9 to 1.5 CFU/100 mL and total coliforms 17.6 to 23.0 CFU/100 mL. Enhanced water quality monitoring improved operational strategies safeguarding the microbial water quality. The E. coli contamination of the drinking water at household level could point at recontamination in the distribution or unsafe hygienic practices at household level. Presence of faecal contamination at household level indicates potential presence of pathogens posing a health risk to consumers. Increasing chlorine dosage ensured good microbiological drinking water quality but changing the number of supply cycles had no such effect.

Determining the changes in the urban water footprint (WF) of the Tibetan Plateau is important for sustainable development within this region and in downstream regions. Taking Xining, the largest city on the Tibetan Plateau, as an example, this study quantified the changes in the WF of this region in the 2005-2018 period. We found that Xining\'s total WF increased by 22.6%, from 8.9 billion to 10.9 billion m3 in this period. The increase in Xining\'s gray WF (WFgray) resulting from the intensification of urban point-source pollution was the primary cause of the increase in its total WF. Xining\'s WFgray from point-source pollution increased by 75.3%, from 3.1 billion to 5.4 billion m3. In addition, Xining\'s WF far surpassed the amount of available water resources (WA) in this region. It is possible to prevent Xining\'s WF from exceeding its WA only by simultaneously controlling point- and nonpoint-source pollution in the future. Thus, it is recommended that great importance be attached to the rapid increase in the WFgray of the Tibetan Plateau resulting from rapid urbanization and that effective measures be implemented to control point- and nonpoint-source pollution, so as to safeguard sustainable development within the Tibetan Plateau and in downstream regions.

Drinking water supplied by private wells is a national concern that would benefit from improved outreach and support to ensure safe drinking water quality. In North Carolina (NC), local health departments (LHDs) have private well programs that enforce statewide well construction standards, offer water testing services, and provide well water outreach and assistance. Programs were evaluated to determine their capacity and capability for well water outreach and assistance and identify differences among programs. All LHDs reported overseeing the construction of new wells as required by law. However, services provided to existing well users were offered infrequently and/or inconsistently offered. Lack of uniformity was observed in the number of LHD staff and their assigned responsibilities; the costs and availability of well water testing; and the comfort of LHD staff communicating with well owners. While the total number of staff was lower in LHDs in rural counties, the number of outreach activities and services offered was typically not related to the number of well users served. Variations in structure and capacity of well programs at LHDs have created unequal access to services and information for well users in NC. This research underscores the need to examine infrastructure that supports the well water community on a national scale.