Abstract The source identification and distribution of normal alkanes and polycyclic aromatic compounds in suspended particulate matter from Great Kwa River obtained during low and high tide was carried out using gas chromatography-mass spectrometry (GC-MS) technique. The study involves the use of geochemical parameters (ratios) such as unresolved complex mixture (UCM), Carbon preference index (CPI), Dominant carbon maximum (Cmax), n-alkane proxy ratio (Paq) and LHS/SHC to determine the sources of n-alkanes in the study sample. The occurrence of UCM in the Gas chromatogram of the sample shows petroleum contamination. The alkane proxy (Paq) was used to evaluate the origin of long chain alkane and the result shows its source as an indication of submerged/ floating species of microphyte. The LHC/SHC ratio shows microbial/ petroleum source. The PAHs detected and quantified in the samples were not the regular PAHs and were found from diagenetic products of organic matter transformation as well as the biosynthesis of microbes and plants. The results shows that the n-alkanes were predominantly petroleum inputs as the secondary source (allochthonous) continental inputs and microbes inputs from organic matter such as macrophytes, terrestrial plant wax and phytoplanktonic derived organic matter as its primary sources (autochthonous) planktonic inputs. Low tide influences the accumulation and distribution of persistent n-alkanes and PAHs than high tide due to sedimentation.
Keywords n-Alkanes, Polycyclic Aromatic Compounds.