Source apportionment of polycyclic aromatic hydrocarbons (pahs) in coastal sediments of phang nga province

Abstract

Using PAHs as an environmental indicator is suitable for implications the anthropogenic influences on the Phang Nga coastal area. The concentration, composition and spatial distribution of PAHs were investigated in the study area. The total concentrations of the 13 PAHs were ranged from 11.9 to 272.0 ng g-1 dry weight, with an average of 57.1±35.7 ng g-1 dry weight. The distribution pattern of PAHs in the background group (Koh Phra Thong) can be characterized as pyrogenic in origin due to relatively higher contribution from HMW PAHs with 4~6 rings. In case of the hot spot group, the highest percentage of 5-6 ring PAHs was found at stations in front of Pakarang Cape, indicating fuel combustion or street run-off as the predominant sources. The diagnostic PAHs ratios and fingerprints indicated that the promising PAH sources might be originated from the traffic-related sources such as petroleum combustion, street dust, road paving asphalt, tires and leaking of petroleum used by shipping activities. In addition, application of the multivariate descriptive statistical techniques (e.g. HCA and PCA) also identified the three possible sources of PAHs to be road dust, fuel combustion and grass/wood combustion. As a consequence, all of the promising sources implied that this coastal marine have been impacted with high anthropogenic activities. However, the levels of PAHs in the study area did not exceed the ERM and should not cause acute biological damages, Although at one site D[a,h]A exceeded the ERL/TEL values only one station. Moreover, the PAHs results indicated that the 2004 Tsunami backwash played a key role in transporting anthropogenic PAHs to the sediment approximately 25 kilometers far away offshore.