Risk Assessment of Water from Hand-Dug Wells: A Case Study in Aflao in the Ketu-South Municipality in the Volta Region of Ghana.

Abstract

Numerous peri-urban and rural areas in developing countries like Ghana face challenges with access to quality potable water due to reliance on contaminated groundwater sources. This study assessed the quality of hand-dug wells in Aflao using a cross-sectional survey. The data collection involved sanitary inspections and a survey of 400 household wells based on the WHO standard observation checklist. Water samples from 20 wells were analysed for microbial and heavy metal contaminants (Pb, Cd, Cr, Ni & As) using membrane filtration technique and atomic absorption spectrometry respectively. We found 37.3% of wells were within 10 meters of the latrine location, 98% lacked concrete floors, 98.3% lacked covers, and 88.5% had poor or no drainage systems, 31.8% were under trees, and all wells (100%) had shallow depth (<30 m). Microbial loads exceeded WHO guidelines: all samples (100%) contained total coliforms (32 – 1209 cfu/100 ml), while faecal coliforms and specifically E. coli were in 90% (18/20) of samples (0 – 186 and 0 – 93 cfu/100ml, respectively). Sanitary risk factors (latrine proximity, absence of concrete floors and well covers, inadequate drainage, wells under trees, and shallow depth) strongly correlated (p< 0.05; OR >1) with microbial contamination. All the heavy metals tested (As, Cd, Cr, Ni & Pb) were below minimum detection limits (0.001 – 0.01mg/L. Majority (70.3%) of well users perceived the water quality to be acceptable. Failed microbial quality and correlation with sanitary risk factors confirmed that unprotected hand-dug wells were unsafe water source for consumption without treatment.