A discussion on ecological risk assessment of polycyclic aromatic hydrocarbons in some bottom sediments of the Songhua River

Abstract：Bottom sediments from the Songhua River were analyzed to determine the total content and distribution patterns of 16 main polycyclic aromatic hydrocarbons (PAHs). The PAHs concentrations vary from 226.86 to 10079.68 ng·g-1, with the mean value being 2230.04 ng·g-1. The 4～6 rings PAHs possess 61.6 %, whereas 2～3 rings PAHs possess 38.4%, suggesting the derivation of PAHs mainly from pyrogenic (coal, oil, natural gas and wood) burning in the Songhua River. Petroleum sources only exist in the downstream of the Nenjiang River in Qiqihar City and the main stream of the Songhua River in western Zhaoyuan County. For evaluating the potential ecological risk of PAHs in the Songhau River, the potential ecological risk of PAHs was assessed on the basis of Effects Rang-Low (ERL), from low ring to high ring. There are components containing more PAHs than the ERL in the upstream and downstream of the Second Songhua River in Jilin City; Nap, Ace, Fl in the Nenjiang River of southeastern Tailai County and DBA in the Songhua River in Bayan County are higher than the ERL too. It should be noticed that such high levels of PAHs in the bottom sediments will result in potential ecological risk for the environment.