Evaluation of some physicochemical parameters and benthic macroinvertebrates of Ikere Gorge Reservoir in Oyo State, Nigeria

Abed-Nego Osayande Aiwerioghene,Abeke Ayoade Adedolapo

doi:10.4314/jasem.v20i4.25

Abed-Nego Osayande Aiwerioghene, Abeke Ayoade Adedolapo

Open Access

https://doi.org/10.4314/jasem.v20i4.25

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Abstract

The physico-chemical parameters and benthic macroinvertebrates of Ikere Gorge Reservoir were studied to assess the impact of anthropogenic activities on this man-made lake by collecting surface water and benthic samples. Physico-chemical parameters were within the allowable limits of USEPA for fresh water bodies apart from conductivity (0.055 ± 0.002μS/cm) which was below standard. There were significant differences (p<0.05) in the mean values of DO, BOD, TDS, transparency, nitrate and sulphate between the sampling stations. A total of six genera (Chironomus, Melanoides, Cloeon, Bulinus, Bellamya and Hirudo) of benthic macro-invertebrates belonging to six orders (Diptera, Pelecypoda, Ephemeroptera, Heterobranchia, Caenogastropoa and Hirudinida) were recorded in the reservoir during the study. Pollution tolerant species including Melanoides tuberculata and Chironomus sp. dominated the benthic macroinvertebrates with a total number and percentage abundance of 674(56.88%) and 435(36.71%), respectively. Ikere Gorge Reservoir is relatively under stress due to dominance of indicators of pollution. Keywords : Anthropogenic activities, Bioindicator, Ikere Gorge Reservoir, Melanoides tuberculata, Water quality.

Highlights

In Nigeria, several researchers have used the composition and distribution of macroinvertebrates to indicate the health status of water bodies ( including Arimoro, 2007; Ayoade and Olusegun, 2012; Andem et al, 2013; Okoroafor et al, 2014), there is paucity of data on the Ikere Gorge reservoir (the only manmade lake on Ogun River)
The mean temperature and pH values for the three sampling stations of Ikere gorge Reservoir studied were comparable with previous studies done on some selected water bodies in the south-western Nigeria (Etim and Adie, 2012)
From the Principal component analysis (Fig. 1) showing the interaction between physico-chemical parameters and benthic macroinvertebrates, it was observed that the distribution and abundance of some benthic macroinvertebrates such as Mayfly nymph (Cloeon dipterum), Bulinus sp., Leech (Hirudo species), and Bellamya unicolor were determined by changes in some physico-chemical parameters such as pH, DO, BOD, conductivity, transparency, nitrate, sulphate and phosphate

Summary

Introduction

In Nigeria, several researchers have used the composition and distribution of macroinvertebrates to indicate the health status of water bodies ( including Arimoro, 2007; Ayoade and Olusegun, 2012; Andem et al, 2013; Okoroafor et al, 2014), there is paucity of data on the Ikere Gorge reservoir (the only manmade lake on Ogun River). This study is designed to evaluate the physicochemical parameters and benthic macroinvertebrates of Ikere Gorge Reservoir and this will provide information on the health status of this water body.

Results

Conclusion