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Impact of the plant rhizosphere and augmentation on remediation of polychlorinated biphenyl contaminated soil
Author(s) -
Singer Andrew C.,
Smith Daniel,
Jury William A.,
Hathuc Khoiviet,
Crowley David E.
Publication year - 2003
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/02-471
Subject(s) - bioaugmentation , rhizosphere , biostimulation , chemistry , environmental remediation , polychlorinated biphenyl , environmental chemistry , soil water , soil contamination , brassica , bioremediation , phytoremediation , contamination , horticulture , bacteria , environmental science , biology , soil science , ecology , heavy metals , genetics
This study investigated the interactive effects of bioaugmentation, biostimulation, and the rhizosphere during remediation of Aroclor 1242‐contaminated soil. Treatments were repeatedly augmented with polychlorinated bipheny (PCB)‐degrading bacteria, inducers (carvone and salicylic acid), surfactant (sorbitan trioleate), minimal salts medium in a 20‐cm high soil column, or a combination of these elements. Soils containing a single Brassica nigra plant achieved 61% PCB removal in the 0 to 2 and 2 to 6 cm depths after 9 weeks of bioaugmentation, whereas only 43 and 14% PCB removal, respectively, was achieved in unplanted controls. Gas diffusion coefficients of 13.0 and 5.0 × 10 −7 m 2 s −1 were calculated from a methane diffusion assay for planted and unplanted soils respectively, indicating the positive effect of plant roots on gas diffusion into the soil. A second, modified column study removed 87, 73, 63, and 45% of PCB after 12 weeks in the 0 to 5, 5 to 11, 11 to 26, and 26 to 35 cm depths, respectively, in planted‐bioaugmented soils, whereas 65, 54, 53, and 47% of PCB was removed from the planted‐minimal salts treatment, respectively. Shifts in the soil microbial community structure were demonstrated by denaturing gradient gel electrophoresis of bacterial 16S ribosomal DNA. Results support that Brassica nigra directly contributed to accelerated PCB removal by increased oxygen diffusion, amendment infiltration, and microbial enrichment.