Journal of Ecology and Rural Environment ›› 2019, Vol. 35 ›› Issue (2): 180-188.doi: 10.19741/j.issn.1673-4831.2018.0078

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Risk Assessments and Partition Characteristics of Heavy Metals in Water and Sediments of Freshwater Polyculture Ponds in Partial Area of Chengdu City

HUO Qing-lin, XIAO Hui, WANG Jun-jie, DONG Yuan-yuan, ZHANG Yu-hao, WANG Dan, CHENG Zhang, ZHANG Shi-rong, XU Xiao-xun   

  1. College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
  • Received:2017-10-25 Online:2019-02-25 Published:2019-03-25

Abstract:

In order to survey the partition characteristics and potential ecological risks of heavy metals in environment of freshwater polyculture ponds in partial areas of Chengdu City, the concentration of six heavy metals (Cu, Zn, Cd, Pb, Cr, Ni) in water and sediments of 10 sampling sites were detected. BCR sequential extraction method was used to analyze the speciation of six heavy metals, and the potential risks of heavy metals were evaluated. The results show that, the annual average concentration of heavy metals in water were up to the Fishery Water Quality Standards, except the concentration of Zn in S8 and S10 sites. The heavy metal concentrations in spring and summer seasons were higher than those in autumn and winter seasons. The annual average concentration of heavy metals in sediments were up to the ERL (effects range-low)standards, except the concentration of Cu in S3、S4 and S8 sites. The Cd in sediments had the highest potential risk. There was no obvious seasonal variation in heavy metal concentrations in sediments. The ratio of weak acid extractable fraction of Cd (22.91%-64.51%) was the highest among all the heavy metals. The reducible fraction of Pb and Cu occupied a large proportion. Zn mainly dominated in residual fraction, with a larger proportion of weak acid extractable fraction and reducible fraction. Cr and Ni were dominated in residual and oxidizable fraction. The order of partition coefficient of heavy metals in water-sediments was Ni > Pb > Cr > Cu > Cd > Zn. Therefore, the pollution control of Cd in freshwater polyculture ponds of Chengdu City should be strengthened.

Key words: Chengdu City, freshwater polyculture pond, heavy metal, partition coefficient, ecological risk

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