Source Apportionment of Hydrocarbons in Ghana's Coastal Sediments: Utilizing Hydrocarbons Ratios and Advanced Statistical Methods

This study presents a comprehensive analysis of hydrocarbon pollution in Ghana's coastal sediments, with a focus on aliphatic hydrocarbons and polycyclic aromatic hydrocarbons. The primary objectives were to identify the sources of hydrocarbon pollution, assess its extent, and understand its implications for environmental management and policy. A total of 15 samples were collected from 5 sampling spots. Soxhlet extraction technique was applied. Analysis was conducted by gas chromatography/flame ionization detector for aliphatic hydrocarbons and gas chromatography/mass spectrometry for polycyclic aromatic hydrocarbons. Isomeric ratios, such as the carbon preference index, low molecular weight to high molecular weight n-alkanes, etc., were used to infer the sources of n-alkanes. Polycyclic aromatic hydrocarbons diagnostic ratios, including Benzo[b + k]fluoranthene/Benzo[a]pyrene, Phenanthrene/Anthracene, etc., were used to predict PAHs sources into petrogenic and pyrogenic sources. The study also utilized statistical tools like principal component analysis-absolute principal component scores-multiple linear regression for a detailed source appointment. The type of aliphatic hydrocarbon detected in samples ranged from C₁₀H₂₂ to C₃₃H₆₈. Concerning aliphatic hydrocarbon, C₂₁H₄₄ has the highest average presence at 5.224 μg/kg of dry mass in sediment samples whereas, C₁₀H₂₂ shows the lowest mean concentration of 1.953 µg/kg of dry mass. The mean concentrations of the polycyclic aromatic hydrocarbons detected in samples ranged from 0.544 µg/kg for Anthracene to 2.168 µg/kg for Acenaphthene. Primary findings revealed a mix of petrogenic and pyrogenic sources in the coastal sediments, evidenced by the varying aliphatic hydrocarbons and polycyclic aromatic hydrocarbons ratios. Notably, the presence of carcinogenic PAHs highlighted potential health risks. The APCS-MLR analysis identified specific sources influencing hydrocarbon pollution. These include crude oil, urban runoff, atmospheric deposition, etc. This research contributes to a better understanding of coastal sediment pollution, serving as a foundation for future environmental policies and sustainable coastal management strategies in Ghana.