Oil-Gas and environmental Nexus: Impact of human actions on selected soil physicochemical parameters in Port Harcourt and its environment, Nigeria

Abstract

Impact of oil and gas activities on quality of soil in Port Harcourt and its environments was assessed. The study evaluates levels of physicochemical parameters associated with oil and gas industry in soils of 9 locations in Port Harcourt and its environs in Rivers State in Nigeria using standard methods. Composite samples were collected by random sampling from each of the 9 test locations, 3 control samples were also collected from each of the study areas. Benzene, Toluene, Ethyl-benzene, and Xylene (BTEX) and Total Petroleum Hydrocarbon (TPH) was measured using Gas Chromatography (Hewlett Packard 5890 Series II Gas Chromatograph FID). Total Organic Carbon (TOC) was measured using ASMD standard methods of analysis (ASMD 2579). Refinery Eleme and Aluu recorded the highest mean levels of BTEX (3.21±0.61 and 3.24±0.18 ppm respectively). The mean levels of TPH in soil were within the EPA acceptable optimum of 50 mg/kg except at A2 (Oquwi). There was significant difference among test samples and control samples as determined by one-way ANOVA (F11, 24=3.395; p=0.006). The highest mean levels of TPH was at A2 (56.70±25.77 ppm). ANOVA revealed that there were significant differences in TOC (p=0.023), BTEX (p=<0.001) and TPH (p=<0.001) among the study areas. Industrial areas I1 [Onne], I2 [Agbada] and I3 [Trans-Amadi] recorded highest levels of TOC. Oil and gas activities in industrial areas in Port Harcourt have highest impact on levels of TOC in soils as compared to agricultural and urbanized areas. Oil and gas activities have negative impact on levels of BTEX. Industrial areas recorded highest levels followed by agricultural areas and lastly urbanized areas. The study concludes that oil and gas activities are a threat to soil health and integrity in Port Harcourt.