Impact of gas and oil-fired power plants on proximal water and soil environments: case study of Egbin power plant, Ikorodu, Lagos State, Nigeria

Abstract

Thermal power plants utilizing gas and/or fuel oil are widespread globally and are fast replacing coal-fired plants in many regions. In this study, we investigated the impact of Egbin thermal power station (a gas and oil-fired plant situated in Lagos State, Nigeria) on physico-chemical characteristics and trace metals concentration of the proximal lagoon water, sediment, soil and biota. Temperature of the water ranged from 29.7 to 30.1 °C and reflected the influence of the power plant operations. Dissolved oxygen ranged from 5 to 8 mg/L, increasing steadily with distance away from the power plant. Highest concentration of As, Cd, Cr, Hg, Pb and Zn were measured in water and corresponding sediment from sampling point closest to the power plant. Furthermore, concentration of As, Cd, Cr and Pb in the lagoon water decreased steadily with distance away from the plant, strongly indicating that their levels in the lagoon are influenced by operations of the power plant. Atmospheric deposition of pollutants was responsible for Cr presence in proximal soil samples. Analysis of trace metals in biota species obtained from the lagoon provide evidence of bioaccumulation of Cd, Pb, Hg and Zn in crabs (Callinectes amnicola) and shrimps (Penaeus notalis), important sources of protein for inhabitants of coastal communities in the area. In addition to revealing a route of human exposure to sub-lethal doses of potentially harmful metallic elements, the study would be useful in predicting the impact of gas and oil-fired power plants in other geographical regions.