Abstract

The storage and distribution of refined Petroleum products involves the use of above the ground storage tanks built in clusters, called Tank Farm. Storage tanks could corrode with time and seep hydrocarbon into the ground which later contaminates groundwater. This research was aimed at assessing the physicochemical parameters, hydrocarbon utilizing  bacteria (HUB) and corrosion causing bacteria in groundwater in the vicinities of tank farms in three different locations (Oghara, Koko, and Warri) and in Asaba without a Tank farm (Control) all located in Delta State, Nigeria. Physicochemical and microbiological parameters were analysed using standard methods. Results showed the following ranges pH, 6.2-6.9; Total Dissolved Solids, 30-37mg/l; Biological oxygen Demand, 0.03-1.01mg/l; and Total Petroleum Hydrocarbon (TPH), 0.87-8.00mg/l. Heavy metal ranges were,  Copper (Cu), 0.05–0.13mg/l; Zinc (Zn), 0.07–0.27mg/l; Iron (Fe), 0.08–0.25mg/l; and Lead (Pb), <0.00–0.01mg/l. There was significant difference (p<0.05) across the means of TPH of the different sampled locations. Generally, TPH exceeded the Department of Petroleum Resources (DPR) target and Intervention limits and Iron was above Federal Ministry of Environment (FMEnv) limit in some points sampled. All other parameters analysed fell below regulatory standard of W.H.O, FMEnv and DPR.  Hydrocarbon utilizing bacterial counts in the groundwater samples ranged from 1.0 x 10⁵– 2.5 x 10⁵ CFU/ml. HUB was not detected in the control samples. Molecularly identified hydrocarbon utilizing isolates were Acinetobacter Junii, Lysinibacillus macrolides, Acinetobacter nocomialis, Morganella morgani. Corrosion-causing bacteria were not detected in the groundwater samples analysed. The presence of potential pathogens and pathogenic Acinetobacter nocomialis which is a serious global threat and TPH that bioaccumulates in organs and its carcinogenic effects in the groundwater samples from the tank farm locations poses a public health concern. Government is advised to provide potable water for the inhabitants of communities around these tank farms to forestall health conditions and diseases that could arise from consumption of these groundwaters.