Phytoremediation of Pyrene in a Cecil Soil under Field Conditions

Abstract

We evaluated the effects of annual ryegrass (Lolium multiflorum Lam.) and phosphorus (P) availability on the dissipation of pyrene added at a concentration of approximately 600 mg kg-1 dry soil in the top 7.5 cm of a Cecil loamy sand (fine, kaolinitic, thermic Typic Kanhapludults) in a 10-month experiment under field conditions in Clemson, South Carolina. Plastic canopies were installed to prevent flooding of plots and raindrop dispersion of pyrene. Treatment factors were pyrene, vegetation, and available P levels. Each of the eight treatments had four replicates. The soil was adjusted to low and high P concentrations (an average of 41 and 66 kg extractable P ha-1, respectively). After a 175-d lag period for all treatments, the rate of pyrene removal followed first-order kinetics. The first-order rate constant was significantly higher in nonvegetated (0.098 d-1) than vegetated treatments (0.034 d-1). These data suggest that the presence of easily biodegradable organic matter from plant roots slowed the removal rate of pyrene. The levels of available P did not affect the rate of pyrene dissipation. Pyrene decreased below the detection limit of 6.25 mg kg-1 dry soil in all treatments after 301 d.

Influence of Nitrogen Addition and Plant Root Parameters on Phytoremediation of Pyrene-contaminated Soil

“…The lack of a pyrene degradation response to the presence of plants may be due to the fact that root exudates and other organic compounds provided accessible and readily bioavailable C to microorganisms, thus reducing degradation of the more complex pyrene C source. The lack of a response of pyrene degradation to the presence of plants has been reported previously (Lalande et al 2003;Olexa et al 2000). In the absence of plants, increased soil N concentrations had a negative effect on pyrene biodegradation.…”

“…Reilley et al (1996) and Chen and Banks (2004) measured pyrene in vegetated soils and found that plants and their associated microorganisms enhanced pyrene degradation. In contrast, Lalande et al (2003) reported that there was a significantly higher degradation rate in unvegetated treatments when evaluating the effect of ryegrass (Lolium multiflorum Lam.) on pyrene degradation.…”

“…Biodegradation of pyrene is frequently reduced by low solubility, limited bioavailability, production of genotoxic and cytotoxic metabolites, and low pyrene-degrading microbial numbers. The half lives reported for pyrene vary from 8 to 260 days depending upon soil and environmental conditions (Gentry et al 2003;Krutz et al 2005;Lalande et al 2003;Olexa et al 2000).…”

Heritability of Phytoremediation Potential for the Alfalfa CultivarRiley in Petroleum Contaminated Soil

“…Phytoremediation, the use of plants to degrade or remove contaminants, has been shown to be effective for petroleum (Reilley et al, 1996;Ferro et al, 1999;Liste et al, 1999;Lalande et al, 2003). Root exudates may provide a source of carbon and energy for microbes, stimulating metabolism and/or co-metabolism of contaminants.…”

Suitability of Scirpus maritimus for petroleum hydrocarbons remediation in a refinery environment

“…Some studies have demonstrated that certain plant species could enhance the degradation of PHC in the rhizosphere (Euliss et al 2008;Peng et al 2009) by increasing the number and activity of soil microorganisms compared with bulk soil (Macek et al 2000;Kaimi et al 2006). Nevertheless, other plant species seemed not to be able to improve remediation efficiency (Lalande et al 2003;Euliss et al 2008). In weathered contaminated soils, phytoremediation face some additional challenges that are not present in recently contaminated soils, like lower chemical extractability and bioavailability of contaminants (Phillips et al 2009).…”