Lead and coliform contaminants in groundwater sources in peri-urban areas of Makurdi, Nigeria

Abstract

Benue State has one of the most populated state capitals in North-central Nigeria, suffering from acute water shortage despite River Benue that runs through the town. The combined effect of inadequate potable water supply and the polluted nature of the River has pushed the populace, especially peri-urban residents, to resort to water from wells and boreholes. This study investigates the possible contamination by lead, and some waterborne pathogenic bacterial burden of water from wells and boreholes. Four peri-urban areas of Makurdi, Nigeria, were selected for the study. A total of 768 samples were randomly collected, 192 from each location.The presence of lead was quantified using Atomic Absorption Spectrophotometer, while the bacteriological assessment was done using Multiple Tube Fermentation Techniques and biochemical tests. The mean value for lead at the different sampling sites ranged from 0.030 to 0.079mg/L. The mean value of lead in all the wells and locations was significantly (P<0.05) higher than the WHO recommended values of 0.01 mg/L for lead. Five species of pathogenic bacteria were isolated and identified, namely E. coli, Salmonella subsp 3B, Enterobacter pagglomeran complex, Klebsiella pneumoniae and Citrobacter freundii. The mean value for E. coli at the different well types ranged from 0.000 to 0.401 CFUX10 and were significantly (P<0.05) different. Water from wells in Makurdi had high lead concentration as well as enteric pathogenic bacteria that render it not fit for human consumption. It is recommended that regulatory agencies should protect wells through the development of relevant guidelines to address the risk of water contamination.