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Chinese Journal of Applied Ecology ›› 2012, Vol. 23 ›› Issue (10): 2701-2707.

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Effects of applying sewage sludge on chemical form distribution and bioavailability of heavy metals in soil.

SONG Lin-lin, TIE Mei, ZHANG Zhao-hong, HUI Xiu-juan, JING Kui, CHEN Zhong-lin, ZHANG Ying   

  1. (College of Environmental Science, Liaoning University, Shenyang 110036, China).
  • Online:2012-10-18 Published:2012-10-18

Abstract: A pot experiment was conducted to study the effects of applying sewage sludge on the chemical form distribution of heavy metals (Cd, Pb, Cu and Zn) in soil and the transfer and accumulation of the heavy metals in soil-plant (ryegrass) system. With the application of sewage sludge, the contents of bioavailable Cd and Zn in soil increased significantly but that of  bioavailable Pb in soil had a significant decrease, and the content of residual form Pb in soil increased by 33.3%-74.5%,  compared with CK. When the application rate of sewage sludge was 50% (M/M) of soil, the contents of  exchangeable and reducible Cu in soil only occupied 0.7% and 02% of the  total Cu respectively. The application of sewage sludge promoted the Cd, Cu and Zn absorption while inhibited the Pb absorption by ryegrass. Multiple linear regression analysis showed that the  Cd, Zn and Cu contents in ryegrass  were positively correlated with the  reducible Cd and Zn and oxidizable Cu contents in soil, respectively, and  Pb content in ryegrass was highly correlated with the soil exchangeable and oxidizable Pb contents. After planting ryegrass, the oxidizable Cd and Cu in rhizosphere soil were transformed into exchangeable Cd and residual form Cu, respectively, the exchangeable and reducible Zn transformed into oxidizable Zn, whereas the bioavailability of Pb was less affected.