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Effects of Dolomitic Limestone Application on Zinc Speciation in Boreal Forest Smelter‐Contaminated Soils
Author(s) -
Hamilton Jordan G.,
Farrell Richard E.,
Chen Ning,
Reid Joel,
Feng Renfei,
Peak Derek
Publication year - 2016
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2016.06.0231
Subject(s) - revegetation , soil water , chronosequence , environmental chemistry , soil ph , lime , chemistry , genetic algorithm , environmental science , ecology , geology , ecological succession , soil science , biology , paleontology
Anthropogenic activities at the HudBay Minerals, Inc., Flin Flon (Manitoba, Canada) mining and processing facility have severely affected the surrounding boreal forest ecosystem. Soil contamination occurred via a combination of metal and sulfuric acid deposition and has resulted in forest dieback and ineffective natural recovery. A community‐led effort to revegetate areas of the landscape through the application of a dolomitic limestone has been met with varied success. Zinc (Zn) speciation has shown to be closely linked to the presence or absence of an invasive metal‐tolerant grass species, with soils being broadly classed into two revegetation response groups. Group I, characterized by the absence of metal‐tolerant grasses, and group II, characterized by the presence of metal‐tolerant grasses. The systematic approach used to lime areas of the landscape produced a liming chronosequence for each group. This study used a combination of X‐ray absorption spectroscopy, X‐ray fluorescence mapping, and X‐ray diffraction techniques to determine the effect of liming on Zn speciation in these chronosequences. Liming group I soils resulted in the formation of a neo‐phase Zn‐Al‐hydroxy interlayer coprecipitate and subsequent rapid boreal forest revegetation. The effect of liming on Zn speciation on the group II soils resulted in a gradual transition of increasingly stable adsorption species, culminating with a stable Zn‐Al‐layered double hydroxide precipitate. Boreal forest vegetation has failed to recolonize group II soils during the study. However, the formation of the layered double hydroxide species resulted in a significant reduction in CaCl 2 –extractable Zn. Further research is required to determine how to promote the revegetation of these soils. Core Ideas For sites where metal‐tolerant grass is absent, liming produces a limited pH response. For sites where metal‐tolerant grass is present, liming has a larger pH effect. Liming metal‐tolerant grass vegetated soils fails to promote boreal vegetation growth. Zn‐Al‐HIM precipitates after liming soils where metal‐tolerant grass is absent. Liming soils with metal‐tolerant grass transforms octahedral adsorbed Zn to Zn‐Al‐LDH.