Effect of biochar on heavy metal immobilization and uptake by lettuce (Lactuca sativa L.) in agricultural soil

Hyuck Soo Kim, Kwon Rae Kim, Ho Jin Kim, Jung Hwan Yoon, Jae E. Yang, Yong Sik Ok, Gary Owens, Kye Hoon Kim

Research output: Contribution to journalArticlepeer-review

219 Citations (Scopus)


Many remediation options have been applied to the heavy metal-contaminated agricultural soils nearby abandoned mining sites mainly due to hazard effects of heavy metals to human through agricultural crop dietary. Hence, the current study was carried to examine the heavy metal immobilizing effect of biochar produced from rice hull and subsequent heavy metal uptake by lettuce. Rice hull biochar was incorporated into a heavy metal-contaminated upland soil at six application rates (0, 0.5, 1, 2, 5, and 10 % (v/v)) and soil biochar mixtures were examined using both incubation and pot trials for cultivation of lettuce. Incubation studies showed that biochar incorporation induced significant declines (>80 %) in the phytoavailable metal pool as assessed via 1 M NH4NO3 extraction, possibly due to increased heavy metal adsorption onto the applied biochar and increases in soil pH. Similar results were also observed in pot trials, where the uptake of heavy metals by lettuce was significantly reduced as biochar application rate increased. Despite the significant decline in soil phytoavailable metal pools, lettuce growth still declined as biochar application rate increased. This was attributed to the adsorption of available nitrogen on to the biochar resulting in nitrogen deficiency. Therefore, when the biochar is used for metal immobilization in agricultural soils, maintaining soil nutrient status should be also considered to ensure optimum growth of the crop plants besides metal immobilization rate.

Original languageEnglish
Pages (from-to)1249-1259
Number of pages11
JournalEnvironmental Earth Sciences
Issue number2
Publication statusPublished - 2015 Jul 26
Externally publishedYes

Bibliographical note

Funding Information:
This study was financially supported by the EI project (project No. 2012000210003), Ministry of Environment, Korea. Dr Gary Owens gratefully acknowledges the financial support of the Australian Research Council Future Fellowship Scheme (grant number FT120100799) for funding his salary.

Publisher Copyright:
© 2015, Springer-Verlag Berlin Heidelberg.


  • Black carbon
  • Charcoal
  • Immobilization
  • Plant availability
  • Soil ameliorant

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Water Science and Technology
  • Soil Science
  • Pollution
  • Geology
  • Earth-Surface Processes


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