Polycyclic Aromatic Hydrocarbons (Pah’s) Concentrations in Oilfield Produced Water from Petroleum Impacted Niger Delta Environment

The Niger Delta region, located in Southern Nigeria, is a significant hub for oil and gas production, fostering economic growth and energy security in West Africa sub-region. Drilling activities in this region generate substantial amounts of Produced Water - a large waste stream that develops in oil and gas exploration and production, where water is brought up from the reservoir together with the oil/gas. These pose significant environmental and health risks. Beyond ancillary components, Polycyclic Aromatic Hydrocarbons (PAHs) which are a group of organic compounds with two or more fused aromatic rings, are the main constituents in Produced Water that constitute critical environmental concern. This study investigates the concentrations of PAHs in Produced Water from a Petroleum impacted Niger Delta environment, compared with samples from an un-impacted location to assess their potential risk to the environment. Fourteen (14) samples of Produced Water were collected from seven (7) different oil drilling locations and analyzed for PAHs specifically classified as “priority pollutants” by the US-EPA,using Gas Chromatography - Mass Spectroscopy (GC-MS). The results obtained from the environmental media revealed elevated levels of some carcinogenic PAHs viz: Benzo(a)pyrene (7.346 ppm), benzo(b)fluoranthene (24.310 ppm), benzo(k)fluoranthene (24.310 ppm), benzo(g,h,i)perylene (7.495 ppm), and indeno(1,2,3-cd)pyrene (10.151 ppm), significantly exceeding acceptable threshold limits of international standards. In contrast, the control samples showed comparatively lower concentrations. The results obtained for the control samples ranged between 0.160 ppm [being the lowest for Benzo(a)pyrene] - 12.771 ppm [being the lowest for Phenanthrene].The results revealed a strong positive correlation between Produced Water and PAH concentrations in the aquatic ecosystem. By assessing the pollution burden and the environmental and health impacts of Produced Water, this study contributes to develop valuable data on the impact of crude oil drilling operations, underscoring the need to mitigate environmental risk and the imperative for sustainable management of Produced Water effluent in the Niger Delta oilfields.