Partitioning of iron and zinc in the catchment alluvial sediments of the River Gbako flood plains around Baddegi, central Bida basin, Nigeria

Abstract

Partitioning of iron and zinc were studied in the alluvial sediments of the River Gbako floodplains around Baddegi using empirical formulas. The samples were cored from three pits (TR-1, TR-2, and TR-3). A study of the particle size distribution and geochemical analysis were performed. The particle size distribution results indicate that the sediments are sand dominated, having more than 50% sand with smaller percentages of clay and silt. Average partition coefficient values of Fe in the sediments are 1.02, 0.83, and 0.88, and for Zn 1.02, 0.95, and 0.83, for the TR-1, TR-2 and TR-3 sites, respectively. The average velocities of Fe mobilization in the sediments are 0.08 m/day, 0.07 m/day and 0.09 m/day for TR-1, TR-2 and TR-3, respectively, and for Zn mobilization are 0.07 m/day, 0.07 m/day and 0.09 m/day, for TR-1, TR-2 and TR-3, respectively. The metals are more preferentially partitioned in the sediments than the water percolating through them, which has an average hydraulic conductivity (K) of 4.2 m/day. The partition behavior of the metals is used to explain contaminant transportation in the alluvial sediments of the River Gbako floodplains around Baddegi and also explains the attenuation of pollutants and the process of natural groundwater purification within the shallow alluvial aquifers of these floodplains.