Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis
The aims of this study were to investigate whether Salix viminalis could grow in a highly creosote contaminated soil and, if so, whether the introduction of the plant enhanced the dissipation of polycyclic aromatic hydrocarbons (PAHs). The purpose was also to examine whether inoculation of two di...
| Autor principal: | |
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| Formato: | Otro |
| Lenguaje: | sueco Inglés |
| Publicado: |
2006
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/11872/ |
| _version_ | 1855571957196521472 |
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| author | Önneby, Karin |
| author_browse | Önneby, Karin |
| author_facet | Önneby, Karin |
| author_sort | Önneby, Karin |
| collection | Epsilon Archive for Student Projects |
| description | The aims of this study were to investigate whether Salix viminalis could grow in a highly
creosote contaminated soil and, if so, whether the introduction of the plant enhanced the
dissipation of polycyclic aromatic hydrocarbons (PAHs). The purpose was also to
examine whether inoculation of two different bacterial strains further enhanced the
decrease of the contaminant. The experiment was conducted in a greenhouse during ten
weeks. The soil was collected at a former wood impregnation site belonging to the
Swedish railway administration, in Krylbo, Sweden. The experiment comprised two
different levels of PAH contaminated soil, the creosote soil used as such or diluted with
an arable soil (1:1). The main PAHs studied in this experiment were phenanthrene,
anthracene, fluoranthene, pyrene and benzo[a]pyrene. The soil samples were extracted
with toluene and analysed by GC-MS. Microbial analyses were made to measure the
number of extracted and cultivable bacteria (CFU/g soil) and dominating bacteria were
tested for gram, fluorescence and oxidase reactions. The plants were infected by some
bacterial disease which probably was an inherent infection of the cuttings and the number
of "healthy" plants was reduced by 2/3 in both the creosote soil and the diluted soil. The
initial PAH concentrations were very high, particularly for fluoranthene and pyrene.
Some PAH degradation occurred in pots without plants, but the dissipation of all studied
PAHs was enhanced in the presence of Salix viminalis and also the reduction of more
recalcitrant compounds such as benzo[a]pyrene was impressive. In the presence of plants
the PAH compounds were reduced in the creosote soil by 67 %, 79%, 77% and 43 % for
anthracene, fluoranthene, pyrene and benzo[a]pyrene respectively compared to the initial
values and by 61 %, 66%, 79% and 30% in the mixed soil. For all studied PAHs the
concentrations in the rhizosphere soil were found to be greater than in the bulk soil and
this could probably be explained mostly by the movement of compounds from the
surrounding soil into the rhizosphere, but partly also by an increased solubility. The
results indicate that the introduction of the inocula was not succesful, but due to the
inadequate number of pots with "healthy" plants no conclusions could be drawn. The
microbial analyses showed a significantly higher number of cultivable bacteria per gram
of soil in treatments with plants both compared to the initial soil and the treatments
without plants. |
| format | Otro |
| id | RepoSLU11872 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2006 |
| publishDateSort | 2006 |
| record_format | eprints |
| spelling | RepoSLU118722017-10-13T08:34:08Z https://stud.epsilon.slu.se/11872/ Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis Önneby, Karin Dept. of Soil Sciences Soil chemistry and physics The aims of this study were to investigate whether Salix viminalis could grow in a highly creosote contaminated soil and, if so, whether the introduction of the plant enhanced the dissipation of polycyclic aromatic hydrocarbons (PAHs). The purpose was also to examine whether inoculation of two different bacterial strains further enhanced the decrease of the contaminant. The experiment was conducted in a greenhouse during ten weeks. The soil was collected at a former wood impregnation site belonging to the Swedish railway administration, in Krylbo, Sweden. The experiment comprised two different levels of PAH contaminated soil, the creosote soil used as such or diluted with an arable soil (1:1). The main PAHs studied in this experiment were phenanthrene, anthracene, fluoranthene, pyrene and benzo[a]pyrene. The soil samples were extracted with toluene and analysed by GC-MS. Microbial analyses were made to measure the number of extracted and cultivable bacteria (CFU/g soil) and dominating bacteria were tested for gram, fluorescence and oxidase reactions. The plants were infected by some bacterial disease which probably was an inherent infection of the cuttings and the number of "healthy" plants was reduced by 2/3 in both the creosote soil and the diluted soil. The initial PAH concentrations were very high, particularly for fluoranthene and pyrene. Some PAH degradation occurred in pots without plants, but the dissipation of all studied PAHs was enhanced in the presence of Salix viminalis and also the reduction of more recalcitrant compounds such as benzo[a]pyrene was impressive. In the presence of plants the PAH compounds were reduced in the creosote soil by 67 %, 79%, 77% and 43 % for anthracene, fluoranthene, pyrene and benzo[a]pyrene respectively compared to the initial values and by 61 %, 66%, 79% and 30% in the mixed soil. For all studied PAHs the concentrations in the rhizosphere soil were found to be greater than in the bulk soil and this could probably be explained mostly by the movement of compounds from the surrounding soil into the rhizosphere, but partly also by an increased solubility. The results indicate that the introduction of the inocula was not succesful, but due to the inadequate number of pots with "healthy" plants no conclusions could be drawn. The microbial analyses showed a significantly higher number of cultivable bacteria per gram of soil in treatments with plants both compared to the initial soil and the treatments without plants. Syftet med examensarbetet var att undersöka Salix viminalis förmåga att växa i en kraftigt kreosotkontaminerad jord och huruvida växten bidrog till en ökad nedbrytning av polyaromatiska kolväten (PAHer). Avsikten var också att studera hur nedbrytningen påverkades av tillsats av två bakteriestammar som visat sig intressanta vad gäller nedbrytning av PAHer. Den kreosotkontaminerde jorden som användes i försöket kommer från ett område, Krylbo, där SJ tidigare bedrivit impregnering av slipers. Jorden innehåller höga halter av åldrade PAHer, med initiala värden överstigande 1000 ppm för t ex fluoranten och pyren. Den kontaminerade jorden användes som sådan samt späddes (1:1) med en okontaminerad jord insamlad strax utanför impregneringsområdet. Försöket pågick i växthus under tio veckor och provtagning skedde efter fyra, åtta och tio veckor i led utan plantor och efter tio veckor i behandlingarna med planta. De PAHer som i huvudsak studerades närmare under försöket var antracen, fluoranten, pyren samt benzo[a]pyren. Kompletterande mikrobiella analyser genomfördes med avsikt att beräkna bakteriepopulationer (viable count) samt isolera och gruppera de vanligast förekommande bakterigrupperna genom oxidas-, gram-, fluorescenstest. Två tredjedelar av plantorna påverkades så pass kraftigt av en bakterieinfektion att dessa fick uteslutas ur den slutliga bearbetningen av analysresultaten. Studien visade att en viss nedbrytning av fluoranten och pyren skett efter tio veckor i krukor utan växt, både i blandjorden och i den rena kreosotjorden. Resultaten visar en ökad nedbrytning av alla de studerade PAHerna i närvaro av Salix viminalis där koncentrationerna av antracen, fluoranten och pyren reducerades med 67, 79 respektive 77 % i den rena kreosotjorden och med 61, 66 respektive 79 % i blandjorden jämfört med intitialjorden. Benzo[a]pyren minskade med 43 % i kreosotjorden och med 30 % i blandjorden, vilket är ett lovande resultat då benzo[a] pyren tillhör de mer svårnedbrytbara PAHerna. De reducerade koncentrationerna kan vara en följd av en ökad mikrobiell aktivitet i jorden och därmed en ökad mibrobiell nedbrytning. Detta resonemang stärks av resultaten från viable count som visar på ett ökat antal bakterier i behandling med växt. Andra eventuella orsaker till den ökade nedbrytningen kan vara växtens produktion av biosurfaktanter, vilka ökar lösligheten av PAHerna och därmed tillgängligheten för mikrobiell nedbrytning. PAH koncentrationerna för alla PAHer i studien konstaterades öka i rhizosfärjorden jämfört med jorden i hela krukan, vilket troligen främst kan förklaras av en ökad rörelse mot rotzonen genom vattenupptag, men också en ökad löslighet av PAHerna kan vara en bidragande orsak. Det gick inte att se någon effekt på nedbrytningen till följd av bakterieinokuleringen, men på grund av det begränsade antal friska plantor och en stor variation mellan replikaten kan ingen slutsats dras utav detta. Undersökningen visar på Salix viminalis förmåga att både överleva i den kraftigt kontaminerade jorden och dess förmåga att bidra till PAH-nedbrytningen. Ytterligare försök är dock nödvändiga för att kartlägga de bakomliggande mekanismerna. 2006-02-07 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/11872/1/onneby_k_171013.pdf Önneby, Karin, 2005. Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis. UNSPECIFIED, Uppsala. Uppsala: (NL, NJ) > Dept. of Soil Sciences <https://stud.epsilon.slu.se/view/divisions/4023.html> urn:nbn:se:slu:epsilon-s-7801 eng |
| spellingShingle | Dept. of Soil Sciences Soil chemistry and physics Önneby, Karin Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis |
| title | Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis |
| title_full | Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis |
| title_fullStr | Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis |
| title_full_unstemmed | Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis |
| title_short | Phytoremediation of a highly creosote-contaminated soil by means of Salix viminalis |
| title_sort | phytoremediation of a highly creosote-contaminated soil by means of salix viminalis |
| topic | Dept. of Soil Sciences Soil chemistry and physics |
| url | https://stud.epsilon.slu.se/11872/ https://stud.epsilon.slu.se/11872/ |