ABSTRACT
Sediments can act as sinks for contaminants, including heavy metals. This study assessed the geochemical assessment of heavy metals in sediments from River Ovia. A total of nine (9) sediment samples were collected at each sampled stations from June 2023 to August 2023. Sediments physiochemical parameters such as pH, electrical conductivity (EC), organic carbon (OC), potassium (K), sodium (Na+), calcium (Ca), magnesium (Mg), total nitrogen (N), total hydrocarbon content (THC) sand, silt, clay were analysed using various recommended routine laboratory analysis. Concentrations of heavy metals were determined using Atomic Absorption Spectroscopy.
The result of this study showed that the average mean concentration of heavy metals and total hydrocarbon content in sediments from River Ovia were 545.58±24.91 (Fe), 0.61±0.10 (Ni), 0.41±0.03 (Pb), 0.48±0.27 (Cr), 6.01±1.88 (Zn), 39.02±13.42 (Mn), 7.56±1.06 (Cu) and 25.59±3.96(THC) mg/L respectively. The concentration of heavy metals in sediment samples from River Ovia exists in the following order: Fe>Mn>Cu>Zn>Ni>Cr>Pb. Enrichment factor (EF) indicated that there is moderate enrichment of Pb, Zn, Mn, a significant enrichment for Fe, Ni, Cr and Cu. Geoaccumulation index (Igeo) values indicates Pb was practically unpolluted to moderately polluted, Fe, Ni, Cr, Zn, Mn and Cu were moderately polluted. The contamination factor (CF) showed a moderate contamination for Pb, a considerable contamination for Fe, Ni, Cr, Mn, and Cu. The contamination degree (CD) showed a very high degree of contamination (CD≥24) across the sampled stations. Pollution load index (PLI was > 1) indicating pollution exists in River Ovia. The risk level for River Ovia indicated low ecological risk (RI<150). Metal contents exhibited a positivce and significant correlation indicating a common source of pollution.
