Effects of Grasses on the Remediation of Creosote-Contaminated Surface Soil

dc.contributor.authorCrosswell, Scott Brownleeen
dc.contributor.committeechairNovak, John T.en
dc.contributor.committeememberBenoit, Robert E.en
dc.contributor.committeememberWiddowson, Mark A.en
dc.contributor.departmentEnvironmental Engineeringen
dc.date.accessioned2014-03-14T21:36:08Zen
dc.date.adate1999-05-14en
dc.date.available2014-03-14T21:36:08Zen
dc.date.issued1999-05-05en
dc.date.rdate2000-05-14en
dc.date.sdate1999-05-12en
dc.description.abstractA grass phytoremediation field study was initiated in July 1997 at the site of a former railroad tie facility that used creosote for tie preservation. The site is contaminated with polycyclic aromatic hydrocarbons (PAHs). A test matrix consisting of 36 planted (clover, fescue and rye grasses) and unplanted cells was established. The focus of the study was to evaluate PAH remediation in fertilized plots that were unplanted or seeded with clover, fescue or rye. Samples were collected from a depth of 15 to 21 cm, and the six most prevalent PAHs, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene and chrysene were quantified. Data from four sampling periods, t=0, 9, 12 and 17 months is presented. At t=9 months, substantial loss of the five lowest molecular weight (LMW) PAHs had occurred, and the loss was attributed to natural attenuation. During the first 9 months, below average precipitation at the site delayed grass root development. Between t=9 and 12 months, above average precipitation was recorded and this appeared to accelerate chrysene removal rates in both the unplanted and planted cells; however, the rate was higher rate in the planted cells. Similarly, fluoranthene and pyrene degradation seemed to be enhanced in the fescue and rye cells. Over the last 8 months of the study, acenaphthene, fluorene and phenanthrene concentrations approached constant, minimum levels suggesting additional removal will be limited. PAH compounds with higher solubility correlated to decreased constituent soil concentrations. Additional sampling was initiated at t=17 months to compare PAH concentrations with depth. This was done because the observed root mass changed significantly with depth. Samples were taken at two additional depths 10 to 15 and 32 to 38 cm. Increased removal of fluoranthene and pyrene was observed in the uppermost zone, suggesting a role for plants in remediation of these 4 ringed PAHs.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-051299-154926en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-051299-154926/en
dc.identifier.urihttp://hdl.handle.net/10919/42643en
dc.publisherVirginia Techen
dc.relation.haspartetd.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectPhytoremediationen
dc.subjectgrassesen
dc.subjectcreosoteen
dc.subjectpolyaromatic hydrocarbonsen
dc.titleEffects of Grasses on the Remediation of Creosote-Contaminated Surface Soilen
dc.typeThesisen
thesis.degree.disciplineEnvironmental Planningen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Engineeringen

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