Pollution characteristics,ecological risk assessment and sources of polycyclic aromatic hydrocarbons (PAHs) in surface water from the Zhangweinan River
漳卫南运河地表水中溶解态多环芳烃的污染特征、风险评价与来源辨析

The distribution and sources of 16 priority polycyelic aromatic hydrocarbons (PAHs) in surface water from the Zhangweinan River were investigated in this study. The total concentrations of PAHs ranged from 31.7 to 74.5 ng·L~(-1) in April 2008 with an average value of 56.3 ng· L~(-1), and from 45.3 to 99.0 ng·L~(-1) in October 2008 with an average value of 62.9 ng·L~(-1), which is lower than the PAH concentrations in other rivers in the world. The spatial distribution of PAHs showed that Sin si was a heavily polluted site and the estuary was slightly polluted compared to other sampling sites. The temporal distribution showed that concentrations of PAHs in October were higher than those in April. The PAHs were dominated by 2-, 3-, 4-ring components in water samples in April (25.1% ,48.7% and 19.1%) and October (29.9% ,45.5% and 22.9%). A new ecological risk assessment method was introduced in this study. The values of RQ _(∑PAHs(MPCs)) at all sites were 0 and the values of RQ_( ∑PAHs(NCs)) ranged from 34.7 to 111.0 in April with a mean value of 58.4 and from 20.4 to 88.8 in October with a mean value of 49.8. The levels of ecological risk were generally low, and the risk in April was slightly higher than that in October. The ecological risk was the highest at Sinitsi in April and was the lowest at the estuary in October. The molecular indices and isomer pair ratios were used to infer the sources of PAHs, and the results suggest that anthropogenic heavy fuel combustion is the main source. At Sinusi and the estuary, petroleum made a large contribution to PAH pollution.