Quantitative estimation of pollution in groundwater and surface water in Benin City and environs

Abstract

Microbiological and physico-chemical analyses of groundwater and surface water samples collected from different parts of Benin City were carried out to investigate their pollution load. Microbiological analyses were carried out using pour plate method and most probable number (MPN) technique while physico-chemical properties were investigated using standard analytical methods. Microbial colony counts were most prominent in Nutrient Agar medium with values ranging from 7 x 10³ cfu/ml to 59 x 10³ cfu/ml, while counts in MacConkey and PDA ranged from 5 x 10³ cfu/ml to 40 x 10³ cfu/ml and 2 x 10³ cfu/ml to 8 x 10³ cfu/ml respectively. Bacterial and fungal isolates were Bacillus spp. Klebsiella spp. Enterobacter spp. Micrococcus spp. Flavobacterium spp, Serratia marcescens, Aspergillus spp and Candida spp.  The MPN result ranged from 1.0 x10MPN/100ml to 30.0 x10 MPN/100ml. There was no record of fecal coliform count. Physico-chemical parameters were compared with regulatory standards from Federal Ministry of Environment for drinking water and they all fell within permissible limits except (Dissolved oxygen 28-30.55 mgl^-1), total suspended solids (16-44.5mg/l), and Biological oxygen demand (8.3-76.5). This presents socio-economic and public health concerns. Constant monitoring is recommended to provide information on water quality and health guide.

Keywords: Microbial load, Physico-chemical properties, Water sources, Benin City