Abstract: Current Research in Civil and Mechanical Engineering

Abstract:
The environmental impact of oil production activities in sub-Saharan African countries remains understudied, particularly regarding their potential to release toxic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and their derivatives into ecosystems. This study investigated the concentrations and distribution of nitro-, oxy- and hydroxy-derivatives of PAHs in fish species and sediments from the White Nile near Melut oil fields in South Sudan. Analytes were extracted from fish and sediment samples using accelerated solvent extraction and ultrasonic agitation, respectively, with hydroxy-PAHs derivatized by using BSTFA+TMCS, before analysis with Gas Chroma tography-Tandem Mass Spectrometry (GC-MS/MS). Levels of PAH derivatives in sediments (61.8-757, 10.7-182, and 0.34-124 ng g-1dw for nitro-, oxy-, and hydroxy-PAHs, respectively) showed no significant variations amongst sampling locations. In fish, mean levels of the pollutants (748-955, 77.8-242, and 95.7-291 ng g-1ww, for nitro-, oxy-, and hydroxy-PAHs, respectively) were significantly higher in Lates niloticus compared to Oreochromis niloti cus and Clarias gareepinus. In all samples, low molecular weight compounds (2-3 rings) were more abundant than high molecular compounds (contributed 77%, and 81% to the ∑PAH derivatives in fish and sediments, respectively). Diagnostic ratios sug gested that the PAH derivatives were primarily petrogenic, but health risk assessments suggested minimal health risks to humans through the consumption of fish from the White Nile. Biota-sediment accumulation factors (BSAF) values in fish revealed higher bioaccumulation of lower molecular weight PAH derivatives compared to high mo lecular weight derivatives. The findings underscore the need for follow-up studies within the river system and its catchments to fully understand the environmental and health implications of oil production activities in the region.