Levels of heavy metals, total hydrocarbon and organic carbon contents of sediments from Ikpoba (Edo) and Ethiope (Delta) Rivers of Nigeria

Abstract

The sediment samples of River Ethiope and Ikpoba River were collected and extracted using n-hexane (BDH, England) and the resulting extracts were read at 460nm with a spectrophotometer. The heavy metal analysis was carried out by using atomic absorption spectroscopy. The organic carbon was determined by titrimetric method. The results show that the organic carbon contents were 0.53mg/kg (Ikpoba river) and 0.40mg/kg (Ethiope river). THC contents were 6.50mg/kg (Ikpoba river) and 42.10mg/kg (Ethiope river). The organic contents were very low in both river sediments. The low Organic contents could be attributed to the constant flow of the rivers. Generally, higher hydrocarbon concentrations are often recorded in stations that have oil formations than those without oil formations. Some of the results obtained for the heavy metals analysis were higher than the WHO standards. The THC analysis from Ikpoba river sediment was lower compared to WHO standards, while the THC in Ethiope river sediment was higher than the WHO standard. Overall, the parameters analysed were detected in both river sediments, but in varied concentrations.

Keywords: Heavy metals, Total hydrocarbon, Organic carbon