Distribution, seasonal variations and ecological risk assessment of polycyclic aromatic hydrocarbons in the East Lake, China

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants and their presence in urban lakes is of great concern for human and ecological health. One hundred twenty-six surface water samples and 126 surface sediment samples were collected in winter 2012 and summer 2013, respectively, to investigate distribution patterns, seasonal variations, possible pollution sources, and potential ecological risks of 16 priority PAHs in the largest urban lake, East Lake in China. The total concentrations of 16 PAHs in water and sediment ranged from 10.2 to 525.1 ng L-1 and 10.9 to 2478.1 ng g(-1) dry weight, respectively. The concentrations of EPAHs in sediment samples in summer were almost two times greater than those in winter, but the seasonal variations did not differ significantly in the water samples. Diagnostic ratios of indicator PAHs reflected a possibility of pyrolytic PAH input in sediment and a mixture of petroleum and combustion sources in water from the East Lake. The potential ecological risk assessment based on the risk quotient indicated relatively moderate ecological risks of PAHs in the East Lake.