Assessment of vanadium pollution and ecological risk in some selected waste dumpsites in Southeastern Nigeria

Abstract

Waste disposal on dumpsites has resulted in significant vanadium pollution of the soil and ecosystem. This study assessed the pollution status and potential ecological risk of vanadium in some selected waste dumpsites in southeastern Nigeria. In this study, the soil samples were taken from the active waste dumpsites using a stainless-steel soil auger at a depth of 0 - 20 cm. Five sub-samples were taken from each sample location. A control sample was taken from an area devoid of industrial activities and waste dumps. Soil samples were air-dried at room temperature, pulverized with an agate mortar and pestle, and stored using appropriately labeled polythene bags prior to analysis. Vanadium analysis was conducted using an FS240AA atomic absorption spectrophotometer, and the data generated was analysed using IBM SPSS version 20.0 and Ms-Excel 2007. The mean vanadium concentrations in the studied waste dumpsites were found to be in the following order: Okpuno-Egbu dumpsite > Nekede dumpsite > Enyimba dumpsite > Rice-mill dumpsite. Acceptable potential ecological risk indices were observed in the Rice-mill, Enyimba, and Okpuno-Egbu dumpsites, while Nekede dumpsite recorded a high potential ecological risk. Furthermore, the pollution load index revealed that all the studied dumpsites were heavily polluted. Statistical analysis revealed no significant variations in vanadium concentrations in the studied dumpsites (p>0.05). Additionally, there was a strong and positive correlation between the dumpsites of Enyimba/Nnewi (r = 0.634), Nekede/Nnewi (r = 0.615), and Nekede/Rice-mill (r = 0.842). This indicated that the metal found in the dumpsites is of the same origin.