Investigating the Quality of Groundwater from Hand-dug Wells in Lapai, Niger State using Physico-chemical and Bacteriological Parameters

Abstract

Access to potable water is one of the important ingredients for sustainable development of any community. The quality status of groundwater from shallow hand dug well in Lapai area of Niger State, North-central Nigeria was investigated in the present study using physico-chemical and bacteriological indices. A total of 35 groundwater samples were collected from hand-dug wells and analysed for their chemical and bacteriological parameters. Prior to the analysis, the physical parameters were determined insitu using standard equipment in accordance with American Public Health Association Standard for water and waste-water sampling. The geological mapping of the area revealed granite-gneiss as the dominant rock type. The structural analysis of the study area revealed the principal joint direction as NE-SW. The result of the laboratory analyses of the groundwater samples showed that the mean concentrations of the major cations and anions are below the permissible limit recommended by the Nigerian Standard for Drinking Water Quality. However, the mean concentration of iron, copper and zinc in locations along transition zone were found to be slightly higher than their respective recommended maximum permissible limit. Their presence in the groundwater may be attributed to rock-water interaction leading to bedrock dissolution, chemical weathering and dilution effect of the overlapping ferruginous sandstone from the nearby Bida Basin as well as possible leachate from decomposing metallic objects at dumpsites. The groundwater is extremely poor bacteriologically owing to the proximity of hand dug well to unlined soakaways and pit-latrine. The mean concentration of total coliform (150.30 cfu/100ml), E.coli (65.50 cfu/100ml) and faecal strepp (85.40 cfu/100ml) in the hand dug wells from the area implies feacal contamination, an indication that the water is in contact with human or animal faeces and it may be responsible for the occurrence of food borne and waterborne diseases in the area. Physical parameters such as turbidity, conductivity and total dissolved solid show wide range and deviation which is attributable to the presence of the metals and bacteria in the groundwater. Boiling of water before use for domestic purposes is recommended as most bacteria do not withstand elevated temperature. Sensitization of the people on the importance of good hygiene should be carried out in the area.