Rhizoremediation of diesel contaminated soil using Salix alaxensis

McFarlin, Kelly Marie

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Abstract

"An outdoor pot study and a microcosm study were conducted to evaluate the potential for Salix alaxensis (felt leaf willow) to rhizoremediate diesel-contaminated soil. The pot study was conducted for 96 days during an Alaskan interior summer with S. alaxensis grown in soil contaminated with diesel fuel oil #2. The concentration of diesel range organics (DRO) and the most probable number (MPN) of diesel degrading microorganisms in the rhizosphere were measured initially and compared to final values. A microcosm study was also performed with crushed willow roots to simulate root turnover, in which the abundance of diesel degrading microorganisms was also determined. It was hypothesized that treatments containing willow and fertilizer would foster the greatest abundance of diesel degrading microorganisms and thus would provide the largest decrease of diesel range organics. In the pot study, growth of S. alaxensis resulted in the largest decrease of DROs, although treatments amended with fertilizer contributed to a significant increase in MPN of diesel degrading microorganisms. The microcosm study indicated that the addition of crushed willow roots to contaminated soil produced a similar abundance of diesel degrading microorganisms as the addition of salicylic acid. The findings suggest that S. alaxensis can be a useful plant for rhizoremediation of diesel-contaminated soil"--Leaf iii

Description

Thesis (M.S.) University of Alaska Fairbanks, 2010

1.1. Petroleum contamination -- 1.2. PAH biodegradation -- 1.3. Genetics and gene regulation -- 1.4. Cometabolism -- 1.5. Phytoremediation and rhizoremediation -- 1.6. The rhizosphere -- 1.7. Rhizodegradation of of petroleum -- 1.8. The role of plant secondary compounds in rhizoremediation of aromatics -- 1.8.1. Salicylate induces PAH degradation -- 1.8.2. Salicylate contributes to cometabolism -- 1.9. Studies of petroleum rhizoremediation -- 1.10. Evaluating the rhizoremediation potential of Salix alaxensis -- 1.11. Willows in rhizoremediation -- 1.12. Thesis objectives and hypothesis -- 2. Rhizoremediation of diesel contaminated soil using Salix alaxensis -- 2.1. Introduction -- 2.2. Methods -- 2.2.1. Plant material -- 2.2.2. Soil preparation and characterization -- 2.2.3. Experimental design -- 2.2.4. DRO concentration analysis -- 2.2.5. Soil microbial enumeration -- 2.2.6. Microcosm study -- 2.2.7. Statistical analysis -- 2.3. Results -- 2.3.1. Plant biomass -- 2.3.2. Most probable number results -- 2.3.3. Removal of diesel range organics -- 2.4. Discussion -- 2.5. Conclusion -- 2.6. Figures -- 2.7. Tables -- 2.8. References -- Conclusions -- References.

Date

2010-05

Type

Thesis

Collections

Engineering