Occurrence and Ecological Risk of Microplastics in the Upper Usuma River, Abuja, Nigeria

Microplastics tiny plastic particles less than 5 mm in size, are increasingly recognized as a serious threat to freshwater ecosystems. This study explores the presence and ecological risk of microplastics in the Upper Usuma River, Abuja, Nigeria, which is an important source of water for the city. We collected water and sediment samples from upstream, midstream, and downstream sections of the river. Using density separation and visual identification under a microscope, we classified microplastics by their shape and colour. We then assessed ecological risk using the Risk Quotient (RQ) approach. Our findings show that microplastics are present throughout the river, with higher concentrations downstream. Fragments and films mainly from single-use plastics, were the most common types. Ecological risk was low in upstream areas but moderate downstream, suggesting increasing pressure from human activities. This dataset provides the first baseline information on microplastic pollution in the Upper Usuma River and can help guide future monitoring, waste management strategies, and policy interventions to protect freshwater resources in Abuja.