Hydrochemical Assessment of Groundwater Around Osogbo Central Dumpsite, Onibu-Eja, Osun State

Abstract

Groundwater sources around Oshogbo central dumpsite in Osun state, Nigeria, have been evaluated with the aim of detecting possible influence of dumpsites on nearby aquifers and suitability for domestic use. The site covers an area of 79 200m² with an undulating surface. Being part of Ilesha Schist Belt, the major rock types in the area include amphibolites, pegmatites and quartzites. Preliminary tests were conducted on the water samples to determine some parameters, such as PH, Oxidation-reduction potential, Conductivity, Total Dissolve Solids, (TDS), E. Coli, etc, as investigative markers. To detect the presence of Heavy Metals and other parameters, there was random collection of a total of thirty (30) samples of leachates/water, using sterilized bottles. At dried areas, soil samples were collected and distilled water was introduced to extract leachates. The samples were then tested for the following heavy metal pollutants: Cadmium, Iron, Lead, Mercury, Zinc, Chromium, Nickel, Arsenic, Copper, and Cobalt. An appraisal of the results using World Health Organization (WHO’s) and National Standards for Drinking water Quality proved among others, the presence of Mercury, Cadmium, Iron, Arsenic, and high level of Lead contamination. There were also exceeding values of Cadmium in most samples, except in a few others where it was totally absent. Mercury had exceeding values in few samples and absent in the rest of the samples. Heavy metals pollution has harmful effects on the Biological system, via bio-accumulation, and cannot undergo biodegradation. Therefore appropriate remedial treatment is required for the groundwater in the study area since most of the heavy metals in the samples are above the WHO’s and National standards.

Keywords: Heavy Metals, Biodegradation, Pollutants, WHO

DOI: 10.7176/JEES/12-12-04

Publication date: December 31^st 2022