Partition behaviour of iron and zinc in the catchment alluvial sediments of River Gbako flood plains around Baddegi, central Bida basin, Nigeria
Partition behaviors of iron (Fe) and zinc (Zn) were studied in the alluvial sediments of River Gbako floodplains around Baddegi using empirical formulas. The samples were cored from three pits locations (TR-1, TR-2, and TR-3). Particle size distribution and geochemical analysis were performed. Particle size distribution results indicated that the sediments are sand dominated. They have 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 for TR-1, TR-2, and TR-3, respectively, and for Zn are 1.02, 0.95, and 0.83, for TR-1, TR-2 and TR-3, 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 were preferentially partitioned in the sediments than the water percolating through them, with 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 the principle behind groundwater purification in the shallow alluvial aquifers of these floodplains.
Index Terms: Partition coefficient, hydraulic conductivity, alluvial sediments, floodplain, Nigeria