Evaluating the environmental risk and suitability of hand-dug wells for drinking purposes: a rural case study from Nigeria

ABSTRACT

Ikem is an agrarian community, in southeastern Nigeria, reliant on agrochemicals to improve crop yield. These agrochemicals can influence the concentrations of heavy metals, major cations and anions in water, thereby predisposing drinking water to quality deterioration. Therefore, instrumental analyses were performed on water samples to determine the chemical composition, contamination state and evaluate the suitability of groundwater for drinking purpose using numerical models. Water samples were tested for pH, heavy metals (Fe, Zn, Mn and Pb), major cations and anions. Contamination degree revealed that 100% of the water samples have low heavy metals enrichment. Similarly, ecological risk assessment showed that all the heavy metals and water samples pose very low risks and the NIPI revealed that 100% of the samples are under negligible heavy metals pollution threats. Furthermore, pollution index of groundwater showed that all the samples are insignificantly polluted. However, modified water quality index indicated that 12% of the samples are moderately polluted. Quantification of contamination scores of the samples were all negative, indicating that all of the heavy metals were possibly geogenically derived. Based on the findings of this study, the hand-dug wells are excellent sources of drinking water for the rural area. Although the current assessment generally shows that the wells are safe water sources, researches to analyse for other potentially toxic elements and pathogens are encouraged. Also, awareness and protection programs are encouraged for water quality sustainability.

KEYWORDS:

• Environmental risk assessment
• hand-dug wells
• modified water quality index (MWQI)
• pollution index of groundwater (PIG)
• rural drinking water supply

Disclosure statement

The authors hereby declare that there is no conflict of interest regarding this paper.