Systematic Determination of Hydrocarbon Contamination of Shoreline Sediments in Taylor-Creek Sites Niger Delta Region of Nigeria (Published)
The Niger Delta region of Nigeria over the years have been ravaged with series of hydrocarbon contamination/pollution due to various anthropogenic activities related to oil and gas industries. The main aim of this research work was to investigate the total petroleum hydrocarbon (TPH) concentrations in various environmental matrix in the study area, and the efficacy of some alternative analytical techniques for the determination of hydrocarbon concentration in shoreline sediment. A total of fifteen (15) sediment samples were collected and analysed from fifteen (15) sampling locations and a replica sample analysis were carried out for all samples to obtain a sample mean and its standard deviation. The results indicated the presence of TPH concentration at various degree in sediment samples which ranged from 206.9 to 822.0 mg/kg. The TPH mean of 500.1±206.9 mg/kg of sediment sample was above the EGASPIN target value of 50 mg/kg. From the one sample T-test, sediment with TPH total mean concentration of 500.1 mg/kg with a standard deviation of 206.9 with a calculated t-value of 8.425 lies within the rejection region (critical value-1.761, df-14 one sided and a p-value-0.0007). Thus, the null hypothesis is rejected and concluded that the total TPH mean concentration for TC sediment samples of 500.1 mg/kg is greater than the EGASPIN target value of 50 mg/kg for sediment environmental quality standard. While majority of the analysed sediment samples were below the EGASPIN intervention value of 5,000 mg/kg, most of the sample TPH concentration were far above the 50 mg/kg target value. From the one sample T-test, TC sediment with TPH total mean concentration of 500.1 mg/kg with a standard deviation of 206.9j with a calculated t-value of -84.22 lies within the retention region (critical value-1.761, df-14 one sided and a p-value-1). Thus, the null hypothesis is accepted and concluded that the total TPH mean concentration for TC sediment samples of 500.1 mg/kg is less than the EGASPIN intervention value of 5,000 mg/kg for sediment safety limit. Hence, river sediments are contaminated with hydrocarbons in the study area. The study outcome shows that sediment with records of crude oil spill in the past are still contaminated with hydrocarbon which is as a result of poor or none remediation/clean-up of the affected sites, which is attributed to none compliance of extant environmental laws by International Operating Companies (IOCs) operating in the study area and the lack of government regulatory agencies in enforcing the established environmental laws.
Keywords: Niger Delta Region, Nigeria, hydrocarbon contamination, shoreline sediments, systematic determination, taylor-creek sites