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In Situ Bioremediation through Mulching of Soil Polluted by a Copper–Nickel Smelter
Author(s) -
Kiikkilä Oili,
Perkiömäki Jonna,
Barnette Matthew,
Derome John,
Pennanen Taina,
Tulisalo Esa,
Fritze Hannu
Publication year - 2001
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/jeq2001.3041134x
Subject(s) - bioremediation , environmental remediation , environmental chemistry , chemistry , soil contamination , humus , mulch , compost , cadmium , soil water , environmental science , agronomy , contamination , ecology , soil science , biology , organic chemistry
Bioremediation of a heavy metal–polluted soil was investigated in a 3‐yr field experiment by adding mulch to a polluted forest floor. The mulch consisted of a mixture of compost and woodchips. The remediation treatment decreased the toxicity of the soil solution to bacteria as determined by the [ 3 H]‐thymidine incorporation technique, that is, by measuring the growth rate of soil bacteria extracted from unpolluted humus after exposing them to soil solution containing heavy metals from the experimental plots. Canonical correlation analysis was performed in order to identify the chemical and microbiological changes in the soil. The pH of the mulched organic layer increased by one unit. The concentration of complexed Cu increased and that of free Cu 2+ decreased in the soil solution from the mulch treatment. According to basal respiration and litter decomposition, microbial activity increased during the 3 yr following the remediation treatment. The [ 3 H]‐thymidine incorporation technique was also used to study the growth rate and tolerance of bacteria to Cu. The bacterial growth rate increased and the Cu tolerance decreased on the treated plots. The structure of the microbial community, as determined by phospholipid fatty acid (PLFA) analysis, remained unchanged. The results indicate that remediation of the polluted soil had occurred, and that adding a mulch to the forest floor is a suitable method for remediating heavy metal–polluted soil.