Ecological Implications and Source Apportionment of Heavy Metal and Hydrocarbon Contaminants in the Soil of a Poorly Crude Oil Remediated Site in Nigeria: A Case of Ikot Ada Udo Community

The ecological risk and source apportionment of heavy metals and hydrocarbons in soil from the study site was carried out. Composite soil samples (n = 48) were collected from 3 sampling points (SP 1, SP 2, SP 3) within the site at 50, 200, and 500 meters, respectively, from the oil well and from a control site (Ibagwa, Abak) at 10,000 meters from the study site, using a hand-held auger. The samples were analyzed for heavy metals using inductively coupled plasma atomic emission spectrometry (ICP–AES, Yobin Yvon JY-24) and total petroleum hydrocarbon (TPH) using Agilent 6890N Gas Chromatography - Flame Ionization Detector (GC– FID model, Japan). Mean levels of heavy metals and TPH were higher in the study site compared to the control. The mean levels of heavy metals were 0.748 mg/kg (Pb), 0.754 mg/kg (Cd), 1.577 mg/kg (Ni), 0.274 mg/kg (Cr), 4.749 mg/kg (Fe), 0.020 mg/kg (V), 0.103 mg/kg (Co), 0.181 mg/kg (As), 5.544 mg/kg (Mn), and 5.187 mg/kg (TPH). The heavy metals in the soil had an increasing sequence of V