Source and Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediment from Chalong Bay, Phuket, Thailand

Abstract

This study aimed to investigate the spatial distribution and apportionment of potential sources of the 16 US-EPA priority PAHs in surface sediments of Chalong Bay, Phuket, Thailand. A total 28 of sediment samples were collected from areas with high maritime activity in Chalong Bay, subjected to conventional high recovery Soxhlet extraction, purified with SiO₂ column chromatography, and quantified by Gas Chromatography-Mass Spectrometry (GC/MS). Total concentration of PAHs (Σ₁₆PAHs) ranged from 31.15 to 1696 ng g⁻¹ dry weight, with an average of 198.2 ± 318.5 ng g⁻¹ dry weight. Binary diagnostic ratios plots were used to distinguish between petrogenic and pyrogenic sources. Most of the PAHs in sediments originated from pyrolytic sources. PCA analysis explained 82.3 % of the variance by only 4 predominant components. The first principal component (PC1) (26.7 %) was mainly contributed to urban street runoff and municipal wastewater discharge. PC2 (25.8 %) represented vehicular combustion sources, PC3 (19.1 %) was attributed to petrogenic sources, and PC4 (10.7 %) was only associated with Naphthalene. The sources of PAHs distributed around Chalong Bay included oil spills, combustion of fossil fuels by shipping, urban street runoff, and municipal wastewater discharge. Each type of sources affected different locations along shores of Chalong Bay.