All of those factors contribute to the EPZ-5676 order unpredictability of the bioaccumulation of POPs in fishes. 4. ConclusionThe spatial distribution and bioconcentration of PAHs in the water, SPM, and fish species from the Pearl River Delta were examined. Aquatic chemical data were also determined. In both the dissolved and the particulate phases, the low molecular weight PAHs were the dominant components. Positive correlation were found between aqueous PAHs and DOC as well as particulate PAHs and POC, indicating the importance of DOC and POC to the distribution of PAHs in the aquatic environment. The in-situ partitioning coefficients (log Koc, mL/g) for the samples were related to log Kow. The relative lipophilicity of SPM could be evaluated by the slope of the observed regression equation.

PAHs showed significant correlations with lipids in different tissues of fishes. BCF in the viscera of tilapia was positively related to log Kow. But BCF values in most of the fish samples were found to reach the maximum value when log Kow reaches 5�C7 and then decrease when log Kow is higher than 7. The different distribution of PAHs among the fish species and their tissues were affected by log Kow of PAHs and the lipid contents in fish tissues.AcknowledgmentsThe investigation was financially supported by the Key Field Project of the Knowledge Innovation Program, Chinese Academy of Sciences (Y234081A07), the ��Team Program�� Project and a general project of the National Natural Science Foundation of China (Project nos.

41121063 and 40972222), and the Earmarked Foundation of the State Key Laboratory (SKLOG2009A04), the State Science and Technology Ministry of China, which were much appreciated. This is contribution no. IS-1597 from GIGCAS. The authors would like also to thank two anonymous reviewers for the comments for improvement of the paper.
Polycyclic aromatic hydrocarbons (PAHs) are a typical form of persistent organic pollutants with a wide range of distribution in various environmental media in China, particularly in the northern part of the country [1]. The emission sources of PAHs in the environment mainly include fossil fuels, wood fuels [2�C4], oil spills [5], and metal smelting, among others [6, 7]. Hydrophoby and low water-solubility are two typical GSK-3 characteristics of PAHs [8, 9]. In addition, lipid solubility, carcinogenicity, and mutagenicity will increase when the number of rings grows larger [10].