Sources and risk of polycyclic aromatic hydrocarbons in Baiyangdian Lake, North China

The 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in the surface sediments and water of Baiyangdian (BYD) Lake. Total concentration of the 16 PAHs (summation operator 16PAHs) ranges from 229.85 to 1,750.04 microg kg(-1) dry weight for the surface sediments, and varies between 145.10 and 1,311.59 ng l(-1) for the surface water. The PAHs level of BYD Lake is around the midpoint of the global PAHs concentration range. Sources of PAHs in surface sediments were identified by three levels of source identification analysis, which include composition analysis (CA), isomer ratios (IR) and principle component analysis/multiple linear regression (PCA/MLR). Three sources namely coke/coal combustion, diesel emission and vehicle emission were dominant. Their corresponding contributions were 64%, 21% and 15%, respectively. Toxic potency of carcinogenic PAHs in the sediment presents a good relationship with benzo(a)pyrene levels, which indicates benzo(a)pyrene is a good indicator for assessing the potential toxicity of carcinogenic PAHs. The results of risk assessment show that most of the PAHs may not pose unfavourable effects on the aquatic ecosystem. However, it is worthy noting that some of them may exert adverse biological effects.