Comparative Analysis of Trace Metals Content of Rivers Niger and Benue in Lokoja, Kogi State, Nigeria

Abstract

The aim of this research is to determine the levels of some heavy metals content of Rivers Niger and Benue at Lokoja and compare these levels with internationally required or permissible standards for aquatic and human consumption. Four sampling stations each were located on Rivers Niger and Benue at Lokoja, Kogi State. Two water samples were collected from each of the sampling stations once during the second week of each month from April 2019 to March 2020 (12 months). The collected water samples were well preserved and immediately transported to the laboratory for their trace metals content analysis. The analyzed results indicated very low levels of Mn, Cu, Zn, Cr, Pb, and Ca in both rivers, despite their comparatively close variations. The two rivers showed variations in their heavy metal levels without significant difference (P<0.05) among their stations for K, Mg, Fe and Ca, while variation with significant difference (P<0.05) were seen in their Na, Mn, Cu, Pb and Cr concentrations. Most stations in Rivers Benue displayed higher levels of Na, K, and Mg than stations in River Niger. However, both Rivers have high levels of Fe that ranged between 2.33 mg/l to 2.52 mg /l, which are far above the internationally permissible level of 1mg/l (EPA, 1986) for aquatic organisms and human consumption. The research indicated that most aquatic animals in Rivers Niger and Benue at Lokoja are lacking the importance of most trace metals sampled especially Na, K, Mg, Mn, Zn and Ca which are required  for bone, teeth development and general growth. Hence, supplementary sources of Na, K, Mg, Mn, Zn, Cu, Mg and Ca are recommended for water from these rivers for fish culturing, breeding and domestic use. Proper and adequate processing methods should also be employed in treating these water contents for drinking and fish culturing because of the high lethal levels of Fe found in both rivers. All forms of water pollution activities should be discourage through public enlightenment campaigns. All laws and regulations concerning environmental sanitation and indiscriminate waste disposals should be adequately enforced.