Distribution of Polycyclic Aromatic Hydrocarbons in Sediments in Map Ta Phut Industrial Estate Area, Rayong Province, Thailand

Abstract

The distribution of polycyclic aromatic hydrocarbons (PAHs) and the natural characteristics of sediments were investigated in the Map Ta Phut industrial estate area, Rayong province, Thailand, from August 2010 to May 2011. Samples from 20 sites were analyzed using gas chromatography-flame ionization detection. The total concentration of PAHs ranged from 167.73 to 2,467.61 ng.g-1 dry weight with an average concentration of 1,527.07 ± 100.26 ng.g-1 dry weight. It was found that season change did not affect the distribution and accumulation of PAHs in sediments. Almost all sites showed high PAH pollution consisting of five major PAHs—fluoranthene, pyrene, chrysene, benzo(k)fluoranthene and benzo(a)pyrene. The patterns of PAHs in the sediment were dominated by four or five ring compounds estimated to be 85% of total PAHs and the total higher molecular weight PAHs showed higher amounts compared to the total lower molecular weight PAHs. The sources of PAHs were evaluated using composition pattern and molecular mass ratios, which indicated that the PAH input to the Map Ta Phut area came mainly from pyrogenic sources originating from incomplete combustion of fossil fuels and organic substances. However, the measured total PAH concentrations at all sites were below the sediment quality guideline values indicating non adverse effects to the biological environment.