Assessing the Impacts of Microplastic Pollution in the Andoni River Estuary: From Source to Sink.

Microplastic pollution presents serious ecological and socio-economic challenges in aquatic environments globally, with estuaries serving as key sites for the accumulation and transport of these pollutants. This study examines microplastic contamination in the Andoni River Estuary, an ecologically and economically important region in the Eastern Niger Delta, which is under significant pollution stress. Through extensive seasonal and spatial sampling of water, sediments, and biota, the research assesses microplastic distribution, polymer types, and associated environmental risks using the Polymer Hazard Index (PHI) and Pollution Load Index (PLI). Results identify polyethylene (PE) and polystyrene (PS) as the most prevalent contaminants, with specific polymers showing seasonal increases linked to wet season runoff and hydrodynamics. Sediments emerge as long-term reservoirs for microplastic pollution, exhibiting higher hazard indices than water, with contamination hotspots, notably at the Opobo/Ataba Channel, remaining consistent across seasons. The study finds strong correlations between microplastic concentrations in water and sediments, indicating shared transport and accumulation processes. This research provides the first comprehensive baseline for microplastic pollution in the Andoni Estuary and highlights the urgent need for targeted mitigation measures to protect the local ecosystem, fisheries, and public health in the Niger Delta region.