Assessment of Bacterial Communities in a Heavy Metal Contaminated Underground Water in Ikwo Salt Mining Site

Abstract

Heavy metal contamination of underground water due to natural and anthropogenic sources is a global environmental concern. Microbial remediation of a hydrocarbon-contaminated site can be accomplished with the help of a diverse group of microorganisms. The objectives of this project were to determine the bacterial diversity in a heavy metal contaminated region of Enyigba, Ebonyi state. Four samples were collected from the study area (Royal Mining Salt, Enyigba) and a control from Alex Ekwueme Federal University Ndufu-Alike, Ebonyi state in triplicates. The probable tolerant genera were identified using Enterotube which was based on biochemical reactions. The physico-chemical parameters were analyzed and the different concentrations of heavy metals (Zinc, lead, Cadmium, Chromium and Arsenic) were determined using AAS (Atomic Absorption Spectrometer) and its corresponding effects on bacterial communities were determined using the statistical package IBM SPSS Version 22.0. The dominant genera isolated were Pseudomonas spp, Acinetobacter spp, Vibrio spp, and Enterobacter spp in descending order of abundance. The most tolerant genera were subsequently utilized by examining their potential to degrade hydrocarbon. This was achieved by checking the abilities of the isolates to produce biosurfactant and calculating the emulsification index. Pseudomonas spp (86%) was found to have the highest index, followed by Acinetobacter spp (67%). The presence of Sulphate reducing bacteria (SRB) and Acid producing bacteria (APB) were confirmed using API RP-38 and ZPRA-5 test broth respectively. Their presence was attributed to the high concentration of sulphate. This study summarizes the potentials of microbes in hydrocarbon degradation.