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.

The rate of vermi-compost accumulation within 'Tiger Toilets' in India.

Tiger Toilets use a worm-based ecosystem to degrade human waste and have recently been demonstrated as a cost-effective innovation in on-site sanitation. The benefits over traditional pit latrines include slower fill rate, fewer odours, and safer emptying. However, a question remains around how to measure the rate of accumulation of vermi-compost and predict the fill rate into the future. In this study, fifteen Tiger Toilets of varying installation ages in the villages of Jejuri, Bhalgudi and Walhe/Adachiwadi, in Maharashtra province, India were investigated to determine the rate of filling. A laser measure was used to define cross-sections of the depth to vermi-compost layers within the Tiger Toilet digesters. Bench-scale column tests were used to estimate liquid infiltration rates from the digesters into the surrounding soils. Changes over time in the interior digester conditions were photographed and a video camera was installed in selected digesters to confirm and observe the worm activity in situ under red light. Calculated fill rates of the Tiger Toilets were significantly lower compared to estimated fill rates of traditional pit latrines of a similar size and usage rate. The infiltration of the liquid fraction of the waste into the surrounding soil was observed to be a key factor in filling.

A novel theatre-based behaviour change approach for influencing community uptake of schistosomiasis control measures.

BACKGROUND: Appropriate behaviour change with regard to safe water contact practices will facilitate the elimination of schistosomiasis as a public health concern. Various approaches to effecting this change have been trialled in the field but with limited sustainable outcomes. Our case study assessed the effectiveness of a novel theatre-based behaviour change technique (BCT), in combination with cohort awareness raising and capacity training intervention workshops. METHODOLOGY: Our study was carried out in four rural communities in the Mwanza region of Tanzania and in the semi-urban town of Kemise, Ethiopia. We adapted the Risk, Attitude, Norms, Ability and Self-regulation (RANAS) framework and four phases using a mixed methods approach. Participatory project phase engagement and qualitative formative data were used to guide the design of an acceptable, holistic intervention. Initial baseline (BL) data were collected using quantitative questionnaire surveys with 804 participants in Tanzania and 617 in Ethiopia, followed by the theatre-based BCT and capacity training intervention workshops. A post-intervention (PI) survey was carried out after 6 months, with a participant return rate of 65% in Tanzania and 60% in Ethiopia. RESULTS: The intervention achieved a significant improvement in the knowledge of schistosomiasis transmission being associated with poorly managed sanitation and risky water contact. Participants in Tanzania increased their uptake of preventive chemotherapy (males: BL, 56%; PI, 73%, females: BL, 43%; PI, 50%). There was a significant increase in the selection of sanitation (Tanzania: BL, 13%; PI, 21%, Ethiopia: BL, 63%; PI, 90%), safe water and avoiding/minimising contact with infested waters as prevention methods in Tanzania and Ethiopia. Some of the participants in Tanzania followed on from the study by building their own latrines. CONCLUSIONS: This study showed that substantial positive behaviour changes in schistosomiasis control can be achieved using theatre-based BCT intervention and disease awareness training. With the appropriate sensitisation, education and stakeholder engagement approaches, community members were more open to minimising risk-associated contact with contaminated water sources and were mobilised to implement preventive measures.

Rejection of organic micro-pollutants from water by a tubular, hydrophilic pervaporative membrane designed for irrigation applications.

The links between chemical properties, including those relating to molecular size, solubility, hydrophobicity and vapour pressure, and rejection of model aromatic micro-pollutants by a tubular, hydrophilic polymer pervaporation membrane designed for irrigation applications were investigated. Open air experiments were conducted at room temperature for individual solutions of fluorene, naphthalene, phenol, 1,2-dichlorobenzene, 1,2-diethylbenzene and 2-phenoxyethanol. Percentage rejection generally increased with increased molecular size for the model micro-pollutants (47-86%). Molecular weight and log Kow had the strongest positive relationships with rejection, as demonstrated by respective correlation coefficients of r = 0.898 and 0.824. Rejection was also strongly negatively correlated with aqueous solubility and H-bond δ. However, properties which relate to vapour phase concentrations of the micro-pollutants were not well correlated with rejection. Thus, physicochemical separation processes, rather than vapour pressure, drive removal of aromatic contaminants by the investigated pervaporation tube. This expanded knowledge could be utilized in considering practical applications of pervaporative irrigation systems for treating organic-contaminated waters such as oilfield-produced waters.