Evaluation of the Source of Heavy Metals in Stream Sediments of Itapaji-Ekiti, Southwest Nigeria; Insights from Provenance, Risk Assessment and Statistical Analysis

Abstract

This study investigates the geochemical composition of stream sediments in parts of sheet 244, Ado-Ekiti, to understand rock-water-soil interactions, sediment provenance, and potential contamination. Seventeen sediment samples were collected from streams and rivers at a depth of 15–25 cm, air-dried for five days, stored in labeled bottles and analyzed using X-ray fluorescence. Results show that SiO₂ is the most abundant oxide (71.29 wt. %), indicating highly siliceous sediments. Lower SiO₂ concentrations in some samples may result from mineral substitution or leaching of aluminosilicate minerals. Al₂O₃ levels suggest abundant feldspars and micas, while low K₂O and Na₂O concentrations indicate minimal clay mineral content and feldspar leaching. The Na₂O/Al₂O₃ vs K₂O/Al₂O₃ discriminant diagram showed a positive correlation, while binary plots indicate sediment provenance from mafic to felsic igneous rocks. Heavy metal analysis showed moderate contamination by Cr and Cd, with Pb exhibiting considerable contamination factors, leading to an overall low to moderate degree of contamination. The likely sources are sewage effluent discharge and/or agricultural chemical use, which pose risks to water quality, soil health, and aquatic ecosystems. This study underscores the need for continuous monitoring and mitigation strategies to minimize heavy metal pollution and protect environmental and public health in the region.