Water quality assessment of hand-dug well in Sabon-Gari, Zaria, Nigeria

Abstract

This study examined the quality of hand-dug wells in Sabon-Gari area of Zaria, Nigeria. Three sets of sampled hand dug-wells were used for the study. They are small, medium and large wells classified based on their diameter. Water samples were collected from twenty-seven (27) different wells at strategic locations in the city to ascertain suitability of water from the well for human consumption with little or no treatment. The physico-chemical and micro-biological parameters assessed include pH, temperature, dissolved oxygen (DO) biochemical oxygen demand (BOD), total hardness, dissolved solids, total solids, nitrate, chloride, total bacterial count and total coliform count using standard laboratory techniques. Mean values of results obtained were compared with regulatory standards for drinking water by World Health Organization (WHO). Analysis of variance was used to test if there is more variance between the samples than within them. The results revealed high variation between the WHO standards and the obtained values from well water samples. With the exception of pH that fall within the range, the values for total hardness, total dissolved solid, DO, nitrate, chloride and conductivity fall below, while the values for temperature, BOD, bacteria count and coliform count are above the WHO standards. The study therefore recommends that wells should be sited at least 30m away from a possible source of contamination while the surrounding environment should be kept clean and tidy to avoid or reduce contamination.

Keywords: Well water, Quality, Parameters, WHO standards, Zaria