Assessing the Effects of Pit Latrines on Groundwater Quality in Hand Dug Wells in Mtendere East Compound Lusaka

The rapid population growth in Lusaka has brought adverse effects on water supply and sewerage treatment facilities in the district. Consequently, authorities in Lusaka have allowed use of pit latrines, septic tanks, boreholes and wells in the same area in some townships. Mtendere east located about 20.9km from town centre is one of such areas. Lusaka city is built on marble which is cut by a network of fissures that open hollows or filled with soil. This reduces the attenuation of pollutants that would occur through natural filtration. A study on groundwater that was conducted in 2010 in selected areas of Lusaka showed high levels of contamination with bacteria. The general objective of this study was to assess the effects of pit latrines on underground water quality in wells in Mtendere East. Specific objectives were to determine the effect of distance between pit latrines and wells on ground water quality in Mtendere east, to assess the effect of siting water wells and pit latrines in relation to the direction of ground water flow on the ground water quality, to come up with a sampling frequency, to analyse Total and Faecal coliforms, PH, Turbidity, Conductivity, Nitrates and Total Phosphates levels in the water samples collected from the wells in comparison to WHO standards. The study site was purposively selected because all households in the compound used Pit latrines and wells for human waste disposal and drinking water supply respectively. The study population of the area is over 50 000 from which a sample size of 40 houses was raised (Rao soft sample size calculator, at 95% level of confidentiality and 5% level of error). Following oral consent of the respondents, representative members of 10 houses in each of the 4 hand dug well locations were engaged which resulted into a total number of 40 respondents; this was reached by interviewing every 10th household in the area. In each of the households and the site that was visited, water sample from the local well, depth of the wells and that of a pit latrine was taken as well as the distance between the well and the corresponding pit latrines. The majority of water samples collected from households in the first, second and third tests in Mtendere East were found to be contaminated by faecal coliforms, while in the second and third tests the control point was not contaminated by faecal and total coliforms. The study revealed that the direction of groundwater flow had an association with water quality (total coliform and faecal coliform) at 5% significance level with p-values equal to 0.001 and less than 0.001 respectively. Distance from Pit latrine to Wells was insignificant in the quality of water. In conclusion, siting wells and pit latrine systems in the same area was not suitable for Mtendere East compound and Lusaka at large because safety of groundwater cannot be guaranteed. Partners in water resource management such as ZEMA, Department of Water Affairs, Geological Department and Lusaka City Council should, therefore, work together each time projects that involve groundwater development and onsite wastewater treatment are to be implemented. LWSC to quickly finish the water and sanitation project currently under construction so as to provide piped water and sewage services to Mtendere East.