Microplastics in Surface Water of River Nun in Bayelsa Central, Nigeria: Occurrence, Distribution Pattern, and Ecological Risk

Microplastic pollution poses a growing threat to aquatic ecosystems and biodiversity due to its persistence and potential harm to human health. This study examines the occurrence, distribution, and ecological impact of microplastics in surface water from River Nun, Bayelsa Central, Nigeria. Sampling was conducted at six locations over six months (January–March and July–September 2024). Samples were processed using NOAA techniques, including filtration, density separation, and microscopy, while FTIR and GC-MS were used for polymer and additive analysis. Microplastic abundance was lowest in February (40 particles/L) and peaked in August (148 particles/L). Smaller microplastics (<0.3 mm) accounted for 64.1%, with fragments at 61% and beads at 39%. Concentrations ranged from 0.22 ± 0.05 g/L to 0.54 ± 0.16 g/L, with higher values during the rainy season. Some locations exceeded risk thresholds, with risk quotients up to 10.77, posing ecological threats. FTIR identified polymers like polyethylene, polypropylene, and PVC, while GC-MS detected high phthalate levels, particularly dibutyl phthalate and diethylhexyl phthalate (36.72 ppm). These findings emphasize the need for environmental management and community awareness to mitigate microplastic contamination in the Nun River.