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Temperature and microbial activity effects on trace element leaching from metalliferous peats
Shabnam Qureshi1, Brian K Richards, Murray B McBride
1Department of Biological and Environmental Engineering, Riley-Robb Hall, Cornell University, Ithaca, NY 14853, USA.
Journal of Environmental Quality
|December 17, 2003
Summary
Microbial activity, influenced by incubation temperature, significantly impacts trace element release from metalliferous peat soils. Higher temperatures generally increase element loss, but soil pH plays a crucial role in limiting these releases.
Area of Science:
- Environmental Science
- Soil Science
- Geochemistry
Background:
- Peat soils naturally contain elevated trace elements due to geochemical processes.
- Drainage for agriculture initiates the gradual release of these trace elements.
- Understanding trace element release mechanisms is crucial for environmental management.
Purpose of the Study:
- To investigate the influence of incubation temperature on microbial activity and trace element release from two distinct metalliferous peat soils.
- To assess the extent and rate of trace element release under varying microbial activity levels.
- To determine the role of soil pH in mediating trace element mobilization.
Main Methods:
- Incubation of acidic (M7) and neutral (M3) peat soils at temperatures of 4, 16, 28, and 37°C.
- Periodic leaching with synthetic acid rain following incubation cycles to collect leachate.
- Measurement of microbial activity via carbon (C) mineralization and respiration.
- Analysis of leachate for sulfur (S), dissolved organic carbon (DOC), nitrate-nitrogen (NO3-N), and trace elements.
Main Results:
- Microbial respiration was highest at 28°C and lowest at 37°C, with acidic peat (M7) showing greater activity than neutral peat (M3).
- Trace element and dissolved organic carbon (DOC) losses generally increased with temperature (28 > 16 > 4 > 37°C) and were higher in M7 peat.
- Leachate pH influenced analyte concentrations, with lower pH in M7 peat leading to greater losses, while neutral M3 peat pH limited the release of most elements.
Conclusions:
- Microbial processes significantly mediate the release of trace elements from peat soils, with temperature as a key influencing factor.
- The extent of trace element release is strongly dependent on soil properties, particularly pH, with neutral peats exhibiting limited analyte loss.
- These findings highlight the importance of considering microbial activity and soil geochemistry in predicting and managing trace element mobilization from drained peatlands.