Dynamics in leachate chemistry of Cu-Au tailings in response to biochar and woodchip amendments: a column leaching study

Li, Xiaofang, You, Fang, Huang, Longbin, Strounina, Ekaterina and Edraki, Mansour (2013) Dynamics in leachate chemistry of Cu-Au tailings in response to biochar and woodchip amendments: a column leaching study. Environmental Sciences Europe, 25 (Provisional) 32: 1-23. doi:10.1186/2190-4715-25-32

Author Li, Xiaofang
You, Fang
Huang, Longbin
Strounina, Ekaterina
Edraki, Mansour
Title Dynamics in leachate chemistry of Cu-Au tailings in response to biochar and woodchip amendments: a column leaching study
Journal name Environmental Sciences Europe   Check publisher's open access policy
ISSN 2190-4707
Publication date 2013-11-26
Sub-type Article (original research)
DOI 10.1186/2190-4715-25-32
Open Access Status DOI
Volume 25 (Provisional)
Issue 32
Start page 1
End page 23
Total pages 23
Place of publication Heidelberg, Germany
Publisher SpringerOpen
Collection year 2014
Language eng
Formatted abstract
Background Phytostabilization has been advocated as a promising approach to reduce mine tailings' adverse effects to surrounding environment. With many years of efforts in both laboratory and field trials, organic amendments are found to be essential in tailing revegetation. Yet, the associate geochemical dynamics caused by different amendments has rarely been examined. As reactive minerals are usually rich in tailings, geochemical changes induced by amendments would influence seepage management and revegetation strategies. The present study aimed to investigate geochemical dynamics in Cu-Au tailing leachate, in response to amendments with biochar produced from hardwood timber at high charring temperature or woodchips of mixed native tree species in a column leaching experiment under laboratory conditions.

Results showed that the Cu-Au tailings tested in this study were relatively stable after natural weathering, with little resilience of peak salinity, stable pH and low levels of metals in leachate against the six cycles of leaching over 20 weeks. In comparison with the control without any amendments, biochar treatment did not cause any substantial changes in most examined properties of leachate, except for the reduction in dissolved organic C and NO2 -. In contrast, woodchip treatment had a reduced leachate pH and a strong resilience in leachate salinity (and thus major saline ions). The geochemical changes in the woodchip treatment may be related to the active decomposition of woodchips, as indicated by the sharp increases in microbial biomass and activity as well as labile organic C at the end of leaching.

Conclusions The present results suggest that dynamic hydrogeochemical changes may be induced by amendment of fresh biomass like woodchips, which can increase the load of salts and metals in tailing pore water. This may affect seepage water quality at least in the short-term and thus plant survival if tailings are immediately revegetated after amendment. In contrast, biochar with highly stable carbon may help alleviate geochemical environment in the tailings.
Keyword Copper tailings
Column leaching
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Centre for Mined Land Rehabilitation Publications
Official 2014 Collection
Centre for Advanced Imaging Publications
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Created: Mon, 02 Dec 2013, 15:57:38 EST by Xiaofang Li on behalf of Centre For Mined Land Rehabilitation