ABSTRACT

The bacteriological and physicochemical characteristics of the Eziama River, Aba was investigated to assess the extent of pollution of the water due to effluent discharge from brewery and soap industries in Aba. The bacteriological parameters analyzed were total microbial population counts, which ranged from 1.2 x i05to 3.8 x lO5cfulml. The predominant bacteria isolated from four sampling points along the river include Bacillus sp. Pseudomonas aeruginosa, Eschericia coli, Streptococcus faecalis, Kiebsiella pneumoniae, Staphylococcus aureus, Salmonella sp., Micrococcus sp., Alcaligenes sp., Flavobacterium sp. and Acinetobacter sp. The bacterial growth potentials on the soap and brewery effluents were analysed by measuring the optical density, pH and total viable counts of the inoculated medium over a 7-day period. Although effluent mineralization resulted with most of the bacterial isolates tested, wide differences in the extent of mineralization in the presence of each organism were recorded. Physicochemical parameters studied showed that effluent quality discharged by the two different industry types in Aba, differed significantly. Soap industry effluent had significantly high BOD, COD, nitrate, phosphate and sulphate above the maximum permissible levels. Brewery effluent on the other hand, had higher total suspended solids as well as higher nutrient levels. Temperature and alkalinity did not vary significantly with the industrial effluents. Seasonal variations in bacterial heavy metal biosorption were analyzed using atomic absorption spectrophotometer. Bioaccumulation of the metal by bacteria showed the following trend, Fe> Zn >As >Pb >Mn >Hg in the wet season and Fe >Zn >Mn >As > Pb > Hg in the dry season. Seasonal changes in heavy metal concentration showed increases in Pb, from 1.11 mgfL in the wet season to 1.66mgIL in the dry season. Fe increased from 40.65mgfL to 49.78mgIL, while As increased from 2.08 to 2.82mgfL. However, Hg, Zn, and Mn concentrations showed decreases in the wet season. The present study focused on the pollution implications of these effluents from two industry types in Aba, because of the risk of human exposure to them.