EVALUATION OF THE QUALITY OF WATER IN SHALLOW WELLS AT MOKOWE VILLAGE, LAMU COUNTY

Abstract

ABSTRACT Inadequate supply of piped water at Mokowe village in Lamu County has forced the residents to rely on alternative water sources for their daily needs. This water demand has been alleviated through the use of shallow wells. However, most of the wells are located near residential houses below the recommended distance of 30m from the pit latrines; as required by the Ministry of public health (Kenya). This closeness contaminates the aquifer that supplies water to the wells. The study was carried out during wet and dry seasons to evaluate the physicochemical and microbial levels of water from two main shallow wells, namely Salim Hassan and Baoni, with respect to their distance from the pit latrines. Water sample from Himwa tap was collected for comparison. Sampling was carried out thrice during wet season happened in August to September 2015 and thrice during dry season happened in January-February 2016. Water samples were collected and analyzed within 24 hours for total coliforms and Escherichia coli (E.coli) by the most probable number (MPN) method. Physicochemical parameters; fluoride, nitrates and iron were analyzed using spectroscopic (DR 6000). The amount of sodium and potassium was determined using flame photometer. pH and Electrical conductivity were quantified using pH meter. Total dissolve solid (TDS) was determined by evaporation to dryness. Chloride, magnesium, calcium and total hardness were analyzed by wet methods. Odour and taste were quantified using nose and tongue respectively while colour was analyzed using visual comparison method. Total coliforms and Escherichia coli levels in the two wells in wet season were very high compared to dry season. Himwa tap water had nil E.coli which is within the permissible levels nevertheless, total coliform level was beyond the permissible levels. In addition, these values were beyond the acceptable level given by National Environment Management Authority (NEMA). Fluoride, magnesium and iron levels were below the vi allowable limits by NEMA. Chloride, nitrate, sodium, potassium, calcium, total hardness and total dissolved solid were beyond the allowable level provided by NEMA. pH of all the water samples fell within the NEMA standards for drinking water (NEMA, 2006). Himwa water had sodium, nitrate and TDS beyond permissible level while the rest were within the acceptable levels. Odour and taste of the water samples were earthy and sour respectively compared to Himwa tap water which was odourless and sweet in taste. The colour of the water samples was slightly turbid compared to Himwa tap water which was colourless. The samples were highly contaminated by microorganisms hence treatment is recommended before use. However, the physicochemical parameters exceeded the limit can be amended by addition of coagulants in the treatment process. The distance of the two wells to the nearest pit latrines was 11m. For qualitative sampling 225 questionnaires were administered to the residents of Mokowe village