Drinking water quality from rural handpump-boreholes in Africa

Abstract

Groundwater provides a vital source of drinking water for rural communities in many parts of Africa, particularly in the dry season when there are few safe alternative sources. This paper summarises results from a study (n = 428) assessing dry season water quality, both microbiological and inorganic chemistry, in handpump equipped boreholes (HPBs) across the Ethiopia Highlands (n = 142), Malawi (n = 162) and Uganda (n = 124) using a stratified, randomised sampling design. This study seeks to examine general water quality by randomly sampling rural groundwater supplies across larger areas with different geology and climate. The majority, 72%, of HPBs surveyed provide good quality dry season drinking water as defined by WHO drinking water quality criteria. Within this overall picture, the most notable constraints were from thermotolerant coliforms (TTCs), which exceeded the WHO drinking water guideline of zero colony forming units (cfu/100 ml) in 21% of sites (range 0-626 cfu/100 ml). TTC contamination was found to have a significant and positive correlation with annual average rainfall (ρ = 0.2, p = 0.00003). Across all three countries, WHO health based chemical drinking water quality values were exceeded at 9% of sites and were found for manganese (4%), fluoride (2.6%) and nitrate (2.5%); arsenic concentrations were below the guideline value of 10 µg l −1 (range < 0.5-7 µg l −1 ). The high percentage of Mn exceedances (14% ± 5.2% >400 µg l −1 ) found in drinking water sources in Uganda challenges the decision by WHO not to formalise a health-based guideline for Mn. While the overall level of microbiological contamination from HPBs is low, results from this study strongly suggest that at a national and regional level, microbiological contamination rather than chemical contamination will provide a greater barrier to achieving targets set for improved drinking water quality under the UN-SDG 6. Efforts should be made to ensure that boreholes are properly sited and constructed effectively to reduce pathogen contamination.

Microbial Sensing and Removal of Heavy Metals: Bioelectrochemical Detection and Removal of Chromium(VI) and Cadmium(II)

“…Cr(VI) is carcinogenic and toxic even in small amounts which diffuses through the epidermis and reduces to Cr (III) that interacts with nuclear enzymes, proteins nucleotides and DNA [ 8 ]. Ingestion of Cr ions in large amounts can cause stomach upsets and stomach ulcers, convulsion, kidney and liver damage and even death [ 9 ]. On the other hand, cadmium is extremely toxic to humans by bioaccumulation in the kidney and the liver through the food chain [ 10 , 11 ].…”

Barriers to handpump serviceability in Malawi: life-cycle costing for sustainable service delivery

“…3 Furthermore, poor siting, poor construction and improper design for the local context results in poor service delivery in terms of water supply availability and quality. [19][20][21] This contributes to sustainability challenges at the local level, which has been particularly evident by the acceleration to meet the coverage targets of the MDGs, and a risk in the SDGs. 4 The original investments and benefits of increasing the coverage of improved supplies are therefore lost for the communities they are intended to serve.…”

An analysis of hand pump boreholes functionality in Malawi

“…Inorganic chemical analysis was undertaken by CSIRO Land and Water Analytical Services, in Adelaide, South Australia. For a detailed description of methods see Lapworth et al (2020).…”

“…Inorganic water quality is shown to be good across the majority sites with only 16% of sites failing WHO guidelines for key water quality indicators (F, Mn, NO3) -Figure 7. Pathogen Fully functioning good yield, unreliable poor yield poor yield , poor reliability No Flow but worked in last year 55% 43% contamination, as measured by TTC concentrations also affected 16% of sites, however improved well construction and completion could help improve this issue (Lapworth et al 2020). Water quality issues (%) none TTC Inorganic both fully functioning 42.5 7.0 5.0 5.0 good yield, unreliable 7.5 0.5 2.0 0.5 poor yield 5.0 0 0 0 poor yield ,poor reliability 2.5 0.5 0 0 no Flow -not tested 9.0…”