Ecological Risk Evaluation of Heavy Metal Accumulation in Aba River Bottom Sediments: Implications for Soap and Detergent Industry Wastewater Management

Industrial activities have contributed so much to the pollution of water bodies and these pollutions have adversely affected the aquatic ecosystem. This study aimed to investigate the ecological risk evaluation of heavy metal accumulation in Aba River bottom sediments: implications for soap and detergent industry wastewater management. Varian AA240 Atomic absorption spectrometer was used to analyse heavy metals. Individual and complex ecological indices were used to evaluate heavy metal contamination in bottom sediments. According to the results, the heavy metal properties of the wastewater indicated that Fe, Pb, Cd, Cr and Cu mean concentration values were higher than the World Health Organization (WHO) and the National Environmental Standards and Regulations Enforcement Agency (NESREA) permissible limits. Heavy metal properties of the surface water in Aba River (dry seasons) showed that Pb, Cd, Cu, Mn, Fe, and Cr, mean concentrations were above the NESREA, WHO and U.S. Environmental Protection Agency (USEPA) permissible limits. Heavy metal properties of the bottom sediments of Aba River (wet and dry season) showed that Pb, Cd, and Fe mean concentrations were significantly higher than the NESREA, WHO and USEPA permissible limits. The heavy metal contamination factor (CF) of sediments obtained from Aba River during the wet and dry season was low and the CFs of each of the assayed heavy metals were less than 1 (CD < 1). This also signifies the existence of a low contamination in the sediments of the course streams of Aba River during wet and dry season. The pollution load index (PLI) values of Aba River (sediment) indicated that there is no metal pollution at PLI < 1 in the sampled sediments. The potential ecological risk index (RI) of Aba River was less than 150 (RI < 150) indicating a low ecological RI. Abatement of pollutants in the wastewater to permissible concentrations required for natural environment protection is needed.