Investigation of Floodplain Sediment Geochemistry Along the Benue River, Taraba State

Floodplain sediments deposited along the Benue River in Taraba State, North East Nigeria, record the integrated geochemical signature of upstream catchment processes and represent both a natural soil fertility resource and a potential pollution sink in the context of mining and industrial activities upstream. This study investigates the geochemical composition and element distribution of floodplain sediments along selected reaches of the Benue River in Taraba State, evaluating natural background levels and identifying anthropogenic anomalies. Sediment samples were collected from active floodplain surfaces and channel bar deposits at regular intervals over a ninety-kilometre transect from Jalingo towards the Benue State border. Samples were air-dried, disaggregated, and sieved before total digestion and analysis by inductively coupled plasma optical emission spectrometry for major and trace elements. Sequential extraction was applied to selected samples to partition trace metals among carbonate, reducible, oxidisable, and residual fractions, enabling assessment of metal mobility and bioavailability. Grain size and organic carbon content were determined as factors influencing elemental distribution. Principal component analysis was applied to identify geochemical associations and source attribution. The study provides a geochemical baseline dataset for the Taraba State Environment Protection Agency and supports ongoing river basin management activities coordinated by the Benue River Basin Development Authority. Keywords: floodplain geochemistry, Benue River, Taraba State, trace metals, sequential extraction.