Pollution characteristics, ecological risk and sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediment from Tuhai-Majia River system, China

Abstract Sixteen polycyclic aromatic hydrocarbons (PAHs) of surface sediment samples collected from 9 sites of the Tuhai-Majia River system were analyzed. The total PAH concentrations ranged from 311.69 to 3736.32ng/g for dry weight. On average, 2-, 3-, 4-, 5- and 6-ring PAHs consisted of 30.19%, 28.48%, 20.22%, 14.73% and 6.38% of total PAHs, respectively. The risk quotient (RQ) was used to assess the ecological risk of PAHs. The mean values of RQ(MPCs) calculated for individual PAHs were lower than 1.0, with the exception of naphthalene (1.23). RQ∑PAHs calculated for samples indicated that Lijiaqiao, Dashanzhen, and Liaocheng City were determined to be at a low risk level, while Weiwan was determined to be at a high risk level. The sources of PAHs were evaluated by employing ratios of the characteristic molecular markers, indicating that the combustion of fossil fuels and biomass could be the possible sources of PAHs.