Public Knowledge and Perception of Drinking Water Quality and Its Health Implications: An Example from the Makueni County, South-Eastern Kenya

The influence of geology on the quality of groundwater for domestic use: a Kenyan review

Kenya's population, akin to other Sub-Saharan countries, is rapidly growing. With the increasing unreliability of surface water, groundwater resources are becoming highly relied on for domestic and industrial use. Despite several known contaminants reported in different parts of the country, no study has attempted to correlate groundwater quality in the different geological provinces. This review critically synthesizes the influence of Kenya's diverse geology on groundwater quality for human consumption. This was achieved through a review of published journal articles and other research material through research and government databases. Groundwater was categorised based on the major geological provinces including the Archaean volcanic Nyanzian Craton, the Proterozoic metamorphic Mozambique Mobile Belt (MMB) and volcanic Kisii Group, the Palaeozoic and Mesozoic sediments, and Tertiary volcanic Rift Valley. Groundwater quality in these regions showed a characteristic high concentration of fluoride (F-) in volcanic aquifers of the Rift Valley and Nyazian Craton and metamorphic aquifers of the MMB, where mineral dissolution was the main process of F- release. High salinity was common in metamorphic aquifers in the MMB and the Palaeozoic and Mesozoic sedimentary aquifers where mineral dissolution and seawater intrusion were the common contributors to salinity. Other contaminants such as lead and iron were reported in localised areas in the sedimentary and metamorphic aquifers, respectively. Anthropogenic contaminants such as Escherichia coli (E. coli), NO3 -, and NO2 - were common in shallow groundwater resources in most informal settlements in urban areas. Due to the presence of health implications, of the highlighted contaminants, such as fluorosis, high blood pressure and diarrhoea (due to high F- and salinity) in affected regions, this review highlights the need for an active water resource management program in any country relying on groundwater resources to determine the presence of all region-specific potentially harmful chemical elements and mitigation measures in all its water resources.

Assessing the Influence of Hand-Dug Well Features and Management on Water Quality

Underground water quality can be affected by natural or human-made influences. This study investigates how the management and characteristics of hand-dug wells impact water quality in 3 suburbs of Kumasi, Ghana, using a combination of qualitative and quantitative research methods. Descriptive analysis, including frequency and percentages, depicted the demographic profiles of respondents. Box plot diagrams illustrated the distribution of physicochemical parameters (Total Dissolved Solid [TDS], Electrical Conductivity [EC], Turbidity, Dissolved Oxygen [DO], and Temperature). Factor analysis evaluated dominant factors among these parameters. Cluster analysis (hierarchical clustering) utilized sampling points as variables to establish spatial variations in water physicochemical parameters. Cramer's V correlation test explored relationships between demographic variables and individual perceptions of water management. One-way ANOVA verified significant mean differences among the physicochemical parameters. Logistic regression models assessed the influence of selected well features (e.g., cover and apron) on TDS, pH, Temperature, Turbidity, and DO. The findings revealed that proximity to human settlements affects water quality, and increasing turbidity is associated with unmaintained covers, significantly impacting water quality (P < .05). Over 80% of wells were located within 10 to 30 m of pollution sources, with 65.63% situated in lower ground and 87.5% being unmaintained. Other significant contamination sources included plastic bucket/rope usage (87.50%), defective linings (75%), and apron fissures (59.37%). Presence of E. coli, Total coliform, and Faecal coliform rendered the wells unpotable. Factor analysis attributed 90.85% of time-based and spatial differences to organic particle decomposition factors. However, Cramer's V correlation analysis found establishing association between demographic factor associations with individual perceptions of hand-dug well management difficult. It is encouraged to promote hand-dug well construction and maintenance standards to ensure that wells are properly built and protected from contamination sources.

Modulation of the Nrf-2 and HO-1 signalling axis is associated with Betaine's abatement of fluoride-induced hepatorenal toxicities in rats

Sodium fluoride (NaF) ingestion has several detrimental effects in humans and rodents. NaF mechanisms of toxicity include perturbation of intracellular redox homeostasis and apoptosis. Betaine (BET) is a modified amino acid with anti-inflammatory, antioxidant, and anti-apoptotic properties. This study investigates BET's effect on NaF-induced hepatorenal toxicities in rats. Experimental rats (n = 30) were randomly assigned to groups (n = 6) and treated by gavage for 28 days. Group I (2 mL of distilled water), Group II (NaF: 9 mg/kg) alone, Group III: (BET: 100 mg/kg), Group IV: (NaF: 9 mg/kg and BET 1: 50 mg/kg), and Group V: (NaF: 9 mg/kg and BET 2: 100 mg/kg). Our findings revealed significantly (p < 0.05) increased hepatic transaminase activities alongside creatinine and urea levels following NaF-alone treatment in addition to increased oxidative status, lipid peroxidation, reactive oxygen and nitrogen species, decreased superoxide dismutase, catalase, glutathione-s-transferase, glutathione peroxidase, glutathione, and total sulfhydryl groups. The reduced levels of nuclear factor erythroid 2-related factor-2 and the activities of heme oxygenase-1, thioredoxin, and thioredoxin reductase in NaF-alone treated rats equally compromised cellular molecular responses to oxidative stress. Also, NaF increased (p < 0.05) hepatorenal inflammatory biomarkers-nitric oxide, interleukin-10, myeloperoxidase, and xanthine oxidase. Furthermore, caspase-3 and caspase-9 were increased (p < 0.05) in rats treated with NaF alone. Contrastingly, BET was observed to alleviate the harmful effects of NaF. Treatment with BET mitigated NaF-induced oxido-inflammatory responses and apoptosis in the experimental rat's hepatorenal system. The study demonstrates the potential of BET to abate NaF-induced hepatorenal toxicity.

Water chemistry poses health risks as reliance on groundwater increases: A systematic review of hydrogeochemistry research from Ethiopia and Kenya

Reliance on groundwater is increasing in Sub-Saharan Africa as development programmes work towards improving water access and strengthening resilience to climate change. In lower-income areas, groundwater supplies are typically installed without water quality treatment infrastructure or services. This practice is underpinned by an assumption that untreated groundwater is typically suitable for drinking due to the relative microbiological safety of groundwater compared to surface water; however, chemistry risks are largely disregarded. This article systematically reviews groundwater chemistry results from 160 studies to evaluate potential health risk in two case countries: Ethiopia and Kenya. Most studies evaluated drinking water suitability, focusing on priority parameters (fluoride, arsenic, nitrate, or salinity; 18 %), pollution impacts (10 %), or overall suitability (45 %). The remainder characterised general hydrogeochemistry (13 %), flow dynamics (10 %), or water quality suitability for irrigation (3 %). Only six studies (4 %) reported no exceedance of drinking water quality thresholds. Thus, chemical contaminants occur widely in groundwaters that are used for drinking but are not regularly monitored: 78 % of studies reported exceedance of contaminants that have direct health consequences ranging from hypertension to disrupted cognitive development and degenerative disease, and 81 % reported exceedance of aesthetic parameters that have indirect health impacts by influencing perception and use of groundwater versus surface water. Nevertheless, the spatiotemporal coverage of sampling has substantial gaps and data availability bias is driven by a) the tendency for research to concentrate in areas with known water quality problems, and b) analytical capacity limitations. Improved in-country analytical capacity could bolster more efficient assessment and prioritisation of water chemistry risks. Overall, this review demonstrates that universal and equitable access to safe drinking water (Sustainable Development Goal target 6.1) will not be achieved without wider implementation of groundwater treatment, thus a shift is required in how water systems are designed and managed.

Potential fluoride exposure from selected food crops grown in high fluoride soils in the Makueni County, south-eastern Kenya

Makueni County, located in south-eastern Kenya, faces challenges such as limited potable water and restricted food supplies as the result of semi-aridity. High fluoride (F) concentrations have been reported in drinking water with resultant dental fluorosis affecting the local population. To determine the potential F exposure through the consumption of food crops grown in the area, F concentration was assessed in the main five locally grown and consumed crops. Additionally, the water-soluble F fraction was determined from 30 soil samples with mineralogical determination of 20 samples. Mean F concentration in the food crops was in the order; 700, 288, 71.2, 36.6, and 29 mg/kg in kale, cowpeas leaves, green grams, cowpeas (legume portion), and maize, respectively. The F concentration in farm soils ranged from 0 to 3.47 mg/kg (mean of 0.87 mg/kg) and showed a significant strong positive correlation (p = 0.03, r = 0.89) with F values in the crops. Apatite, muscovite, and biotite were identified as the F-rich minerals present. While considering two hypothetical F absorption fractions (75 and 100%), the estimated average daily dose (EADD) of F from consuming the crops ranged between 0.004 and 65.17 mg/kg/day where the highest values were from the vegetables. Most of these values were higher than the F reference dose (RfD) of 0.06 mg/kg. The estimated EADD values of several hypothetical meals prepared from the analyzed crops revealed that steamed kale and maize porridge pose the highest health risk of F associated diseases to the local population, whereas boiled cowpeas pose no health risk. Children, due to their higher daily energy requirement and low body weight, were the most vulnerable group at risk of high daily F intake relative to the RfD. These results suggest that consumption of the analyzed food crops in Makueni County may significantly contribute to F related diseases in the local population. This creates a food security issue for the area because of the potential health risks associated with these crops which are highly relied upon in the semi-arid area with a limited selection of food crops available and viable to grow.

Does Individuals' Perception of Wastewater Pollution Decrease Their Self-Rated Health? Evidence from China

Background: This study used original survey data to quantitatively investigate the associations between individuals’ perception of locally present wastewater pollution and their self-rated health. Methods: This research used the data from large-scale surveys covering all the 31 provinces and equivalent administrative units in mainland China and interviewed 6112 participants. The ordered logit method was employed to estimate the models. Results: The results indicated that individuals’ perceptions of local industrial and domestic wastewater pollution significantly decrease their self-rated health. If industrial wastewater pollution was reported, the possibility of the observers indicating lower levels of self-rated current health, comparing to the past year, and comparing with peers, all increased by 26% (p < 0.001), 23% (p = 0.005), and 18% (p = 0.006), respectively. Likewise, perceived domestic wastewater pollution led to the increase by 21% (p = 0.012), 17% (p = 0.034), and 33% (p = 0.000), respectively. Meanwhile, reported industrial wastewater pollution also has an obvious negative effect on individuals’ health performance, such as being more fatigued and upset. Conclusions: The survey clearly shows that Chinese individuals who are aware of water pollution in their living environment tend to experience more negative health outcomes, which adds additional urgency to improving wastewater treatment.