Heavy metals assessment and associated potential health risk of building sediment deposition in Okpare Creek, Nigeria

Abstract

Heavy metals concentrations in sediments may pose significant threats to human health and well-being of the general ecosystem. Therefore, it's crucial to conduct a thoughtful assessment of sediment characteristics with regards to heavy metal concentration as a raw material for building in the studied area. Twenty sediment samples were collected (five each from localities) and analysed using atomic absorption spectrophotometer (AAS). The highest concentrations of Zn, Cu, Cd, Cr, Pb, V, Fe and Ni were 6.33, 2.65, 0.45, 1,201, 0.38, 0.00, 1026.39 and 0.65 mg/kg respectively in each of the four localities. The results exceeded both recommended limit and other scientist report of similar environment. Also, the health risk impacts computed were all higher than limits. These high values may be attributed to the nature of the area geological formation, application of fertilizer to the farmlands and petroleum exploration and production activities. Cd stood out as the main culprit for potential ecological risks. The average contamination level, as indicated by Igeo values ranging from 0.28 to 0.79 mg/kg, raised concerns, especially at locality 1. Across the board, I-geo values remained generally low (< 2). Cd and Pb, with an I-geo value of about 1, significantly impacted sediment pollution. Average EF values were from 0.02 to 5.76 which revealed that human activities heavily influenced the sediment, marking them as significantly enriched with observed heavy metals. In particular, Cd played a major role in the sediment's enrichment, indicating a high level of environmental impact.