Distribution and Environmental Health Implications of Manganese, Zinc, Mercury, and Arsenic in Surface Water and Sediments

Abstract

Heavy metal contamination of aquatic ecosystems is a major environmental and public health concern, particularly in regions affected by industrial activities. This study investigated the distribution and health implications of Manganese (Mn), Zinc (Zn), Mercury (Hg), and Arsenic (As) in surface water and sediments of the Okulu River in Eleme Local Government Area, Rivers State, Nigeria. Five water and five sediment samples were collected, including four sites impacted by industrial effluents and one control site. Samples were analyzed using Atomic Absorption Spectrophotometry (AAS) and Cold Vapor AAS for Mercury. Results revealed that impacted sites exhibited significantly elevated concentrations of Mn (0.131–8.409 mg/L), Zn (0.178–13.38 mg/L), Hg (0–0.081 mg/L), and As (0–4.835 mg/L), all exceeding World Health Organization (WHO) guideline limits, whereas the control site remained within safe limits. These findings indicate a substantial risk to human health and aquatic life. It is recommended that continuous monitoring, regulatory enforcement, and pollution mitigation strategies be implemented to protect the river ecosystem and surrounding communities