Assessment of Contamination Status of Heavy Metals in Sediment due to Gas Flaring at Esit Eket, South Eastern Nigeria

This study assessed the contamination status of heavy metals in sediment of Esit Eket, south eastern Nigeria due to gas flaring. Six sediment samples were collected into well labeled polyethene bags with the use of a hand trowel at a depth of 10cm during the dry season in the month of February precisely in the intertidal zone at extremely low tide randomly from the flare point to a distance of about 250m away from the flare site. These samples were refrigerated for two days before transported to the laboratory to analyze for heavy metals concentration using a particle induced x-ray emission (PIXE) technique. Heavy metals such as Titanium (Ti), Chromium (Cr), Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Rubidium ( Zirconium (Zr) and Lead (Pb) were Rb), Strontium (Sr),analyzed.The meanconcentration values of these metals were4739.73, 83.94, 1782.28, 37519.54, 24.36, 134.68, 56.33, 112.80, 118.60 and 31.85 ppm respectively. The three pollution indices {enrichment factor (EF), geo-accumulation index (Igeo) and contamination factor (CF)} employed to assess the contamination status of heavy metals in sediment samples of the study area revealed the elemental trend to be in descending order in each area of this study Mn>Zn>Pb>Cu>Fe>Sr>Rb>Cr>Ti> Zr. Analysis of multi-variate statistics such as Pearson’s Correlation coefficient and cluster analysis were also applied to ascertain the relationship and sources of investigated heavy metals. Both positive and negative correlations were observed among some heavy metals but at 0.05 levels, while the cluster analysis revealed three main clusters. The study concluded that the ecosystems in the flared sites region are vulnerable to bioaccumulation of heavy metals in the soil. The concentrations of Iron (Fe) in sediments are higher at the study area than every other elements but Manganese (Mn) poses more negative effects than others.