Microplastic contamination in water, fish, and shrimp collected from the Nile River in Upper Egypt poses ecological and human health hazards

Microplastic (MP) pollution is a growing environmental concern, particularly in freshwater ecosystems. This study investigates MP contamination in the Nile River in Upper Egypt by analyzing water samples and two aquatic species, Gambusia sp. and Caridina nilotica. Samples were collected from three sites with varying anthropogenic influences, and MPs were characterized based on shape, size, color, and polymer composition using FTIR spectroscopy. Results revealed a high MP concentration in water (4.5 ± 2.1 particles/L), with significant spatial variation. The highest contamination was recorded in urban-influenced areas, highlighting domestic and industrial waste as key pollution sources. Fibers (75 %) were the most abundant MP type, followed by fragments (19 %), with polyethylene terephthalate (PET) being the dominant polymer (79 %). Both Gambusia sp. and C. nilotica exhibited MP ingestion, with higher loads detected in Gambusia sp. Feeding preferences were observed, with Gambusia sp. favoring fragments and C. nilotica preferring fibers. Risk assessments classified MP pollution as extremely high, with severe ecological risks (RI > 1200). Initial estimates of human exposure through water consumption suggested that adults may ingest 5,840-12,373 MP/kg body weight annually, while children may ingest 3,103-6,187 MP/kg body weight for the best- and worst-case exposure scenarios. These findings highlight significant MP contamination in the Nile, raising concerns about ecosystem and human health risks. Urgent mitigation strategies, including improved waste management and pollution control, are necessary to reduce MP exposure and protect aquatic biodiversity.