Greenhouse gas emissions from a Cu-contaminated soil remediated by in situ stabilization and phytomanaged by a mixed stand of poplar, willows, and false indigo-bush

ABSTRACT

Phytomanagement of trace element-contaminated soils can reduce soil toxicity and restore soil ecological functions, including the soil gas exchange with the atmosphere. We studied the emission rate of the greenhouse gases (GHGs) CO₂, CH₄, and N₂O; the potential CH₄ oxidation; denitrification enzyme activity (DEA), and glucose mineralization of a Cu-contaminated soil amended with dolomitic limestone and compost, alone or in combination, after a 2-year phytomanagement with a mixed stand of Populus nigra, Salix viminalis, S. caprea, and Amorpha fruticosa. Soil microbial biomass and microbial community composition after analysis of the phospholipid fatty acids (PLFA) profile were determined. Phytomanagement significantly reduced Cu availability and soil toxicity, increased soil microbial biomass and glucose mineralization capacity, changed the composition of soil microbial communities, and increased the CO₂ and N₂O emission rates and DEA. Despite such increases, microbial communities were evolving toward less GHG emission per unit of microbial biomass than in untreated soils. Overall, the aided phytostabilization option would allow methanotrophic populations to establish in the remediated soils due to decreased soil toxicity and increased nutrient availability.

KEYWORDS:

• greenhouse gases
• microbial community composition
• microbial biomass and activity
• denitrification activity
• phytomanagement

Acknowledgments

Dr. Mench is grateful to ADEME, Department of Urban Brownfields and Polluted Sites, Angers, France (F. Cadière as supervisor); the European Commission under the Seventh Framework Programme for Research (FP7-KBBE-266124, GREENLAND); and the ERA-NET Facce Surplus (INTENSE project) for supporting the field trial, as well as the site owner. The University of Florence thanks the Ente Cassa di Risparmio di Firenze for the financial support offered for the acquisition of new instruments.

Funding

The research was supported by the Ministry of Education of the Czech Republic (LC 06066) and by the Czech Science Foundation (Spots of methane production and consumption in terrestrial ecosystem: key for understanding methane turnover, 526/09/1570) the Grant Agency of the AS CR (No. IAA600660605).