Chemical characterization of polycyclic aromatic hydrocarbons (PAHs) in 2013 Rayong oil spill-affected coastal areas of Thailand.

Among Southeast Asian countries, Thailand has gradually accustomed to extremely prompt urbanization, motorization, and industrialization. Chonburi and Rayong provinces are two provinces involved in "eastern seaboard" industrial zones, which is an emerging economic region that plays a key role in Thailand's economy. The 2013 Rayong oil spill did not only cause damages to the coastal and maritime environment, but also undermine trust in the overall safety system and negatively affect the investor confidence. In this study, 69 coastal soils collected around Koh Samed Island were chemically extracted and analyzed for 15 PAHs by using a Shimadzu GCMS-QP2010 Ultra system comprising a high-speed performance system with ASSP function. In this study, numerous diagnostic binary ratios were applied to identify potential sources of PAHs. Advanced statistical techniques such as hierarchical cluster analysis coupled with principal component analysis were also conducted for further investigations of source identifications.

Risk assessment of the presence of polycyclic aromatic hydrocarbons (PAHs) in coastal areas of Thailand affected by the 2004 tsunami.

The total concentrations of twelve, likely carcinogenic, polycyclic aromatic hydrocarbons (PAHs) (i.e., phenanthrene (Phe), anthracene (An), fluoranthene (Fluo), pyrene (Pyr), benz[a]anthracene (B[a]A), chrysene (Chry), benzo[b]fluoranthene (B[b]F), benzo[k]fluoranthene (B[k]F), benzo[a]pyrene (B[a]P), indeno[1,2,3-cd]pyrene (Ind), dibenz[a,h]anthracene (D[a,h]A), and benzo[g,h,i]perylene (B[g,h]P) in backwash deposits of the 2004 Khao Lak tsunami were carefully investigated and compared with the concentrations of world marine sediments (WMS). In general, ∑12PAHs in this study (i.e., 69.43 ± 70.67 ng g(-1)) were considerably lower than those values observed in marine sediments from Boston (54,253 ng g(-1)), coastal sediments from Barcelona Harbour (15,069 ng g(-1)), and riverine sediment from Guangzhou Channel (12,525 ng g(-1)), but were greater than values from coastal sediments in Rosas Bay (12 ng g(-1)), Santa Ponsa Bay (26 ng g(-1)) and Le Planier (34 ng g(-1)). The total toxic benzo[a]pyrene equivalent (TEQ(Carc)) values calculated for Khao Lak coastal sediments (KCS), Khao Lak terrestrial soils (KTS), and Songkhla Lake sediments (SLS) were 10.3 ± 12.2 ng g(-1), 16.0 ± 47.7 ng g(-1), and 5.67 ± 5.39 ng g(-1), respectively. Concentrations of PAHs at all study sites resulted in risk levels that fell into the "acceptable" range of the US EPA model and were much lower than those of other WMS. The cancer risk levels of PAH content in KCS ranged from 7.44 × 10(-8) to 2.90 × 10(-7), with an average of 1.64 × 10(-7) ± 8.01 × 10(-8); this value is 119 times lower than that of WMS. In addition, soil cleanup target levels (SCTLs) for both non-carcinogens (i.e., Phe, An, Fluo and Pyr) and carcinogens (i.e., B[a]A, Chry, B[b]F, B[k]F, B[a]P, Ind, D[a,h]A and B[g,h,i]P) in the KTS samples were estimated for all target groups, with an average value of 115,902 ± 197,229 ng g(-1).

Predictions of gas-particle partitioning coefficients (K(P)) of polycyclic aromatic hydrocarbons at various occupational environments of Songkhla Province, Thailand.

Ambient air samples were collected over periods of 24 hours and 3 hours using a Graseby-Anderson high volume air sampler with PM10 TE-6001 at 15 sampling sites, including an urban residential zone, rural area, industrial factories, waste incinerator, traffic areas and agricultural burning areas in Songkhla Province, Thailand. An analysis of organic carbon and elemental carbon was conducted to estimate the gas-particle partitioning of PAHs using a model proposed by Dachs-Eisenreich. The estimated LogK(P) of PAHs emphasized the risk for lung cancer among outdoor workers in waste incinerators, traffic intersections and bus terminals, suggesting the role of the carbonaceous fraction over the gas-particle partitioning of PAHs. Analysis of f(SC)K(SA)delta(OCT)/F(OM)K(OA) ratios revealed a significant role of adsorption and absorption in unusually high elemental carbon fractions (ie low OC/EC ratio) in fine particles collected at waste incinerators and the abnormally high organic carbon fractions (ie high OC/EC ratio) observed in those fine particles of an urban residential zone, respectively. The dual mode of ab/adsorption tended to dominate the gas-particle partitioning of LMW PAHs collected at the traffic intersections and bus terminal.