Characteristics and distribution of polycyclic aromatic hydrocarbons in sediments from Donggang river and its tributaries, Taiwan.

Analyses of environmental xenobiotic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), were an important worldwide issue because of their detrimental effects on aquatic biota. In this study, we had investigated the distribution, origin and toxicity of PAHs in the Donggang watershed sediments in southwestern Taiwan. The study results showed that the sixteen representative PAHs were detected in all collected samples with concentrations ranging from 23 to 2534 ngg(-1) dw. The highest concentration was detected in the downstream end at near the estuarine portion of the river. The mean ± standard deviation and median of ΣPAH concentrations were 528.5 ± 72.3 and 156 ngg(-1) of dry matrix in collected samples. The highest and lowest concentrations of Σ16 PAHs samples differed significantly (p < 0.05) and naphthalene, phenanthrene, fluoranthene and pyrene were detected in all sediment samples. The random variations between sampling sites were consistent with watershed land use. The present study showed that the ratios of phenanthrene/anthracene (Phe/Ant) and fluoranthane/pyrene (FLu/Pyr) in samples suggested that PAHs sources exhibited mixed pattern of petrogenic and pyrolytic inputs. The PAHs with high molecular weight (5-6 ring) accounted for 95.5% of total-BaPeq while the low molecular weight PAHs (2-3 ring) only appeared 0.20%. There was a high correlation (R(2)= 0.967) between mean concentrations and the BaPeq of the PAHs within the sediments. In summary, the adverse biological effect was low according to the effects-range-low (ERL) values of the Sediment Quality Guidelines (SQGs) in sediments from Donggang river and its tributaries in Taiwan.