Impact assessment of high-risk analytes in produced water from oil and gas industry

This study characterizes and evaluates the constituents of produced water at production wells and dumping sites. The study examined the impact of offshore petroleum mining activities on aquatic systems for regulatory compliance and the selection of management and disposal options. The physicochemical analyses of produced water from the three study locations were within the permissible range for pH, temperature, and conductivity. Of the four heavy metals detected, mercury had the lowest concentration at 0.002 mg/L, while arsenic the metalloid, and iron had the highest concentrations at 0.038 mg/L and 36.1 mg/L, respectively. The total alkalinity values for the produced water in this study are about six-fold compared to the other three locations (Cape Three Point, Dixcove, University of Cape Coast). Compared to the other locations, produced water had higher toxicity to Daphnia, with an EC₅₀ value of 80.3 %. The levels of polycyclic aromatic hydrocarbons (PAHs), volatile hydrocarbons, and polychlorinated biphenyls (PCBs) analyzed in this study were all insignificant in terms of toxicity. The total hydrocarbon concentrations indicated a high level of environmental impact. However, considering the possible breakdown of total hydrocarbons over time, and the marine ecosystem's high pH and salinity conditions, further recordings and observations should be conducted to ascertain the overall cumulative effects of oil drilling activities at the Jubilee oil fields along the shores of Ghana.