Author(s)

T. A. Laniyan, A. F. Abimbola & M. K. C. Sridhar

Abstract

Arsenic is a toxic metal with adverse effect on health, hence the need for geochemical evaluation of water sources to determine the level of arsenic concentration, their sources and propose remediation method to stem the tide of pollution of water in Ibadan, a highly urbanized city in South west Nigeria. Thirty water samples were randomly taken in the study area at locations underlain by quartzite (8), banded-gneiss (14) and augen-gneiss (8). Furthermore, 14 samples of effluents and rocks samples (fresh and weathered) were also collected and analyzed to ascertain the source of arsenic. Remediation studies using the phytoremediation method were carried out. Phytoremediation was done by cultivation of matured water hyacinth (Eichhornia crassipes) in 10.0, 20.0, 50.0 and 100.0 mg/L of arsenic acid. Arsenic content in all the water samples were determined using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Plants were harvested, dried, pulverized and analysed for metal content using inductively coupled-ion chromatography. Mean concentration of arsenic in the water samples underlying rock units was 0.01 mg/L; however, high arsenic concentration was obtained in effluents (0.02 mg/L) and quartzite (0.8 ppm). This implied that water derived from areas underlain by quartzite and in close proximity to effluents could be susceptible to arsenic contamination. The calculated Pollution index for arsenic also revealed high levels of pollution in effluents. Highest arsenic bio-accumulation was found at 100 mg/l in matured water hyacinth. Water sources in Ibadan metropolis are susceptible to arsenic contamination from leaching of weathered quartzite

Keywords

arsenic, effluents, contamination, toxic, remediation, urbanized, quartzite, pollution, water hyacinth, phytoremediation