Polycyclic Aromatic Hydrocarbons in the Coastal Sediments of Southwestern Taiwan: an Appraisal of Diagnostic Ratios in Source Recognition

Fifty seven surface sediment samples along the coast of southwestern Taiwan were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs). Concentrations of total PAH (sum of 28 PAH compounds) ranged from15 to 907 ng/g dry weight (dw). Diagnostic ratios revealed petroleum origin PAHs was a significant source to the sediments at Gao-ping estuary stations. However, sediments of Kaohsiung coast might be a combustion-derived PAHs of petroleum, coal, and vehicles. The result of perylene/penta-aromatic PAHs ratio was higher in Tainan coast, Hsinda harbour coast, and some off-shore stations of Kaohsiung coast, suggesting a diagenetic PAH source. A comprehensive appraisal suggested that certain diagnostic ratios are much useful in tracing the distribution of PAHs from specific sources in southwestern Taiwan. P/A (phenanthrene/anthracene) ratio is a better indicator than MP/P (methylphenanthrenes/phenanthrene) ratio in tracing petrogenic PAHs. Moreover, BaA/Chr (benzo(a)anthracene/chrysene) and IP/BghiP (indeno(1,2,3- c,d)pyrene/benzo(g,h,i)perylene) ratios can provide more appropriate assignments than BaP/BeP (benzo(a)pyrene/benzo(e)pyrene) and BbF/BkF (benzo(b)fluoranthcene/benzo(k)fluoranthcene) in distinguishing PAHs from various pyrogenic sources in this study. More specifically, automobile and coal sources were found dominant in stations of pyrogenic group delineated by principal component analysis (PCA).