Characterization of PAHs in surface sediments of aquaculture farms around the Pearl River Delta.

The distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of freshwater fishponds and mariculture rafts around the Pearl River Delta (PRD) were investigated. Twenty-one sample sites were chosen, consisting of fifteen freshwater fishponds and six mariculture rafts. The total PAH ( summation SigmaPAH) concentrations measured in all the sediment samples ranged from 52.7 to 717 ng g(-1), with mean of 184 ng g(-1). The marine sediment samples contained higher levels of summation SigmaPAH, high molecular weight (HMW) PAHs and carcinogenic PAHs than freshwater sediments (p<0.05). Principal component analysis/multiple linear regression analysis (PCA/MLRA) indicated that the source of PAHs in freshwater sediment was mainly derived from mixed combustion of coal, wood, and vehicle emission (66.2%). Vehicle emissions and coal combustion were the main sources (52.5 and 47.5% of summation SigmaPAH, respectively) of PAHs contaminated in the marine sediments. The present study indicated that surface sediments of freshwater fishponds and mariculture rafts around the PRD were grossly contaminated by PAHs derived from combustion sources.