This difference might be caused by the feeding habits of different fish species in different aqueous environment.Figure 6Distribution of total PAHs and lipid (%) in fish species from the Pearl River Delta.Significantly different concentrations of PAHs were also observed among fish tissues. Because the visceras of Cirrhinus mrigala, red grass carp, blunt snout bream-2 collected Rapamycin structure in April 2011, and carp were mashed, only the data of their muscle and gills were present. The highest concentrations of PAHs were found in the visceras, ranging from 80.51 to 180.87ng/g dry weight, followed by the concentrations in gills, ranging from 25.43 to 236.14ng/g dw, and those in muscle (10.52 to 46.85ng/gdw) are the lowest.
The different concentrations of PAHs in fish tissues may be affected by the physical-chemical properties of PAHs, the lipid content, and the uptake capacity of different fish tissues [9].3.3. Association of PAHs with DOC in Water and with POC in SPMOne of the important factors affecting PAHs in the water and SPM samples was DOC and POC. Correlation analyses between PAHs and DOC or POC were illustrated in Figure 7. Although aqueous PAHs showed no significant correlations with DOC in summer, positive correlations were found between aqueous PAHs and DOC in both the Dongjiang River (r = 0.736,P < 0.05) and the Pearl River (r = 0.78, P < 0.01) in spring. For the particulate samples, PAHs in SPM was significantly related to POC in summer (r = 0.695, P < 0.05) in Dongjiang River and in both the Pearl River (r = 0.625, P < 0.05) and Dongjiang River (r = 0.783, P < 0.
05) in spring. The highly significant correlation between PAHs and organic carbon indicated that both DOC and POC are important to the distribution of PAHs in aquatic environment.Figure 7Correlations of 14 PAHs with DOC in water samples and with POC in the SPM samples. A-PAHs and S-PAHs correspond to the dissolved PAHs and particulate PAHs, respectively.Moreover, the slopes in Figure 7 demonstrate the importance of DOC to the association of PAHs. The slopes are ?0.788, 12.19, and 7.63ng/mg for DOC, and 50.71, 37.97, and 22.79ng/mg for POC in the Dongjiang River in summer, in the Dongjiang River and in the Pearl River in spring, respectively. Hence, PAHs should be greatly affected by POC than by DOC in the targeted river system. It is also widely acknowledged that Koc is closely related to Kow [25].
Hence, hydrophobic compounds such as PAHs with higher Kow show stronger affinity to POC or DOC. The four dominant PAHs (acenaphthylene, fluorene, fluoranthene, and pyrene) in the dissolved and the particulate phases were normalized by DOC and POC, respectively (Figure 8). It was found that the mean POC-normalized concentrations for Flo, GSK-3 Flu, and Pyr were 21.79, 13.84, and 12.74��g/g oc, respectively; and the mean DOC-normalized concentrations were 1.57, 1.50, and 2.67��g/g oc, resp.).