Vertical Profile of PAHs and Dredging Depth of River Sediments

Abstract

Sediment dredging is an effective engineering measure to reduce the negative effects of PAHs pollution on water environment. The dredging depth is a key parameter in environmental dredging engineering. A guidance of environmental dredging depth needed to reduce the toxicity risk was developed which was specifically designed for the removal of river sediments contaminated by PAHs based on the mean effect range median quotients (mean-ERM-q). The dredging depths for removing river sediments were calculated based on the vertical profile of PAHs content and the quality guidelines of sediment. Pinghu water system was carried out to determine the dredging depths of sediments from nine rivers by the proposed method. Each sediment core was collected from different river. The results showed the profiles of PAHs in sediment cores were irregular and diverse due to river dredging events and human activities in different periods. The risk assessment of PAHs toxicity showed one of nine cores with moderate-high probability, 4 of nine cores with low-moderate probability and the others with low toxicity risk. The achievement can offer a reference to the dredging engineering in other similar river systems.

Keywords:

• PAHs
• river sediments
• toxicity risk
• environmental dredging depth

Acknowledgments

This study was supported by National Science and Technology Major Protects for Water Pollution Control and Treatment (No. 2017ZX07201004), National Natural Science Foundation of China (No. 51579046), Natural Science Foundation of Zhejiang Province (No. LGF18E090009).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China, (51579046). Natural Science Foundation of Zhejiang Province, (LGF18E090009). National Science and Technology Major Protects for Water Pollution Control and Treatment, (2017ZX07201004).