Limitations and possibilities for microbial degradation of organic contaminants in aquifers
(2006)- Abstract
- Many factors can influence the rate of microbial degradation of organic contaminants in aquifers. Some of these factors, e.g. sorption, the presence of dissolved organic matter (DOM), biomass, redox conditions, cometabolism, microbial community composition, and activity of degrading microorganisms, are addressed in the thesis, with the ambition to gain insights for bioremediation in aquifers, and to prevent contaminants from spreading to drinking water supplies.
The influence of sorption of organic contaminants and bacteria on biodegradation was investigated under both diffusion limited and advective flow conditions. The results demonstrated that degradation by suspended bacteria of dissolved aniline and... (More) - Many factors can influence the rate of microbial degradation of organic contaminants in aquifers. Some of these factors, e.g. sorption, the presence of dissolved organic matter (DOM), biomass, redox conditions, cometabolism, microbial community composition, and activity of degrading microorganisms, are addressed in the thesis, with the ambition to gain insights for bioremediation in aquifers, and to prevent contaminants from spreading to drinking water supplies.
The influence of sorption of organic contaminants and bacteria on biodegradation was investigated under both diffusion limited and advective flow conditions. The results demonstrated that degradation by suspended bacteria of dissolved aniline and 2,4-dichlorophenol (2,4-DCP) was faster than the degradation of the same compounds sorbed to the solids. Nevertheless, sorption to the solids was not sufficient to exclude trace contaminants from degradation.
In another investigation, the main effect of DOM on microbial phenanthrene degradation in groundwater was stimulation of microbial growth and activity of degrading populations, with hydrophilic DOM having a better effect than hydrophobic.
In another study, glyphosate degradation was different in a mixture of sediment and groundwater from two aquifers (Vejen, Denmark and Vomb, Sweden). Laboratory experiments excluded sorption and organic carbon limitation as major sources of the observed differences. Glyphosate degradation was positively correlated to the density of bacteria, but the difference in density between the two sites was too small to account for the degradation difference. Instead, it was found that the differences in metabolic activity of the degrading strains and the microbial community composition of the aquifers were large and coincided with differences in rates of biodegradation. Glyphosate sorption was lower and biodegradation was slower under anaerobic conditions compared with aerobic, and most of the degraded glyphosate was not mineralized but cometabolized to AMPA.
The thesis pin-points to the possibilities to increase contaminant biodegradation in aquifers by the addition of i) oxygen to stimulate aerobic degradation, ii) a primary growth substrate, e.g. DOM, to increase biomass and thereby stimulate metabolic or cometabolic degradation, and iii) microorganisms to increase the degrading population and/or genetic capacity. (Less) - Abstract (Swedish)
- Popular Abstract in Swedish
Svensk populärvetenskaplig sammanfattning:
Miljögift är mat för bakterier i grundvatten
Jag har undersökt bakteriers nedbrytning av organiska miljögifter i grundvatten och intresserat mig för hur den påverkas av gifternas vidhäftning till sand och bakteriernas aktivitet och mångfald. Sådan kunskap kan bidra till att förhindra gifters spridning till t.ex. drickvatten. De flesta studier av miljögifters nedbrytning är gjorda i det översta jordlagret, medan studier i grundvattenmiljö är betydligt färre. Ett grundvattensediment är näringsfattigare och har färre aktiva bakterier än en jordbruksjord. Därför kan föroreningar stanna kvar längre i ... (More) - Popular Abstract in Swedish
Svensk populärvetenskaplig sammanfattning:
Miljögift är mat för bakterier i grundvatten
Jag har undersökt bakteriers nedbrytning av organiska miljögifter i grundvatten och intresserat mig för hur den påverkas av gifternas vidhäftning till sand och bakteriernas aktivitet och mångfald. Sådan kunskap kan bidra till att förhindra gifters spridning till t.ex. drickvatten. De flesta studier av miljögifters nedbrytning är gjorda i det översta jordlagret, medan studier i grundvattenmiljö är betydligt färre. Ett grundvattensediment är näringsfattigare och har färre aktiva bakterier än en jordbruksjord. Därför kan föroreningar stanna kvar längre i grundvatten.
Om en förorening bara kan brytas ned av bakterier som finns i vattnet i markens porer, kan vidhäftning till sand i marken göra att bakterierna inte kommer åt föroreningen. Nedbryt-ningshastigheten kan då minska och till och med göra att giftet inte bryts ned alls. Vidhäftning till sanden kan också öka nedbrytningshastigheten. Om föroreningen är giftig för bakteriesamhället, kan vidhäftningen minska den annars giftiga koncentrationen i grundvattnet. Eftersom bakterier själva kan sitta på sanden, kan nedbrytningen av föroreningen också gynnas om bakterier och miljögift finns på en yta nära varandra. Jag har undersökt hur nedbrytningshastigheten av några olika miljögifter påverkas av både bakteriers och miljögifters vidhäftning till sand, och funnit att den är snabbare i porvattnet jämfört med då giftet sitter fast på sanden.
Jag har också funnit att löst organiskt material i grundvatten kan stimulera ett miljögifts nedbrytning, framförallt genom att öka tillväxten av de bakterier som bryter ned giftet.
Glyfosat är den aktiva komponenten i ogräsbekämpningsmedlet RoundUp, och är ett av de miljögift som jag har undersökt. I en studie fann jag att nedbrytningshastigheten av glyfosat skiljde sig åt i blandningar av grundvatten och sand från två olika platser (Vejen i Danmark och Vomb i Sverige). Genom experiment kunde jag utesluta att skillnaderna orsakades av skillnader i vidhäftning till sanden och begränsningar i tillgången av näring och mängden bakterier mellan de båda platserna. Istället fann jag en koppling mellan glyfosat-nedbrytningen och sammansättningen av bakteriesamhället och bakteriernas aktivitet. Jag fann också att bakterierna bröt ner glyfosat snabbare i närvaro av syre än i dess frånvaro, men att bakterierna inte kunde använda glyfosat för att tillväxa. Glyfosat bröts inte ned fullständigt utan endast till AMPA, som inte är giftigt.
Avhandlingen pekar på möjligheterna att stimulera bakteriell nedbrytning av organiska miljögifter i grundvatten genom att tillsätta syre, annat organiskt material och/eller nedbrytande bakterier. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/546469
- author
- Carlsson, Christel LU
- supervisor
- opponent
-
- Ph. D. Schroth, Martin H., Institute of Terrestrial Ecology Soil Biology, Eidgenössische Technische Hochschule, Zurich.
- organization
- publishing date
- 2006
- type
- Thesis
- publication status
- published
- subject
- keywords
- Ekologi, mycology, Mikrobiologi, Hydrobiology, biodegradation, Organic contaminants, redox conditions, sorption, DOM, cometabolism, biomass, microbial activity, microbial community composition, Ecology, Microbiology, bacteriology, virology, bakteriologi, mykologi, virologi, aquatic ecology, marine biology, limnology, Miljökemi, Environmental chemistry, akvatisk ekologi, Marinbiologi, limnologi
- publisher
- Christel Carlsson, Department of Ecology, Chemical Ecology and Ecotoxicology, Lund University
- defense location
- Blå Hallen, Ekologihuset, Sölvegatan 37, 223 62 Lund
- defense date
- 2006-04-21 10:00:00
- ISBN
- 91-7105-239-9
- language
- English
- LU publication?
- yes
- additional info
- G. Bengtsson and C. Carlsson. 2001. Contribution of suspended and sorbed groundwater bacteria to degradation of dissolved and sorbed aniline Appl. Microbiol. Biotechnol., pp 234-241.G. Bengtsson and C. Carlsson. 2001. Degradation of dissolved and sorbed 2,4-dichlorophenol in soil columns by suspended bacteria Biodegradation, pp 419-432.C. Carlsson, N. Törneman and A. von Belino. 2006. DOM control of phenanthrene degradation in groundwater (manuscript)C. Carlsson, H-J Albrechtsen and G. Bengtsson. 2006. Cometabolism, cell density, and redox conditions limit glyphosate degradation in aquifers (manuscript)C. Carlsson, S. Bertilsson and G. Bengtsson. 2006. Linking microorganisms to glyphosate degradation in aquifers by isotopic and molecular profiles (manuscript)The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Ecology/Ecotoxicology (Closed 2011) (011006020)
- id
- dead0d06-7cdc-4616-8da3-d65c1e30733b (old id 546469)
- date added to LUP
- 2016-04-04 12:24:51
- date last changed
- 2018-11-21 21:10:49
@phdthesis{dead0d06-7cdc-4616-8da3-d65c1e30733b, abstract = {{Many factors can influence the rate of microbial degradation of organic contaminants in aquifers. Some of these factors, e.g. sorption, the presence of dissolved organic matter (DOM), biomass, redox conditions, cometabolism, microbial community composition, and activity of degrading microorganisms, are addressed in the thesis, with the ambition to gain insights for bioremediation in aquifers, and to prevent contaminants from spreading to drinking water supplies.<br/><br> <br/><br> The influence of sorption of organic contaminants and bacteria on biodegradation was investigated under both diffusion limited and advective flow conditions. The results demonstrated that degradation by suspended bacteria of dissolved aniline and 2,4-dichlorophenol (2,4-DCP) was faster than the degradation of the same compounds sorbed to the solids. Nevertheless, sorption to the solids was not sufficient to exclude trace contaminants from degradation.<br/><br> <br/><br> In another investigation, the main effect of DOM on microbial phenanthrene degradation in groundwater was stimulation of microbial growth and activity of degrading populations, with hydrophilic DOM having a better effect than hydrophobic.<br/><br> <br/><br> In another study, glyphosate degradation was different in a mixture of sediment and groundwater from two aquifers (Vejen, Denmark and Vomb, Sweden). Laboratory experiments excluded sorption and organic carbon limitation as major sources of the observed differences. Glyphosate degradation was positively correlated to the density of bacteria, but the difference in density between the two sites was too small to account for the degradation difference. Instead, it was found that the differences in metabolic activity of the degrading strains and the microbial community composition of the aquifers were large and coincided with differences in rates of biodegradation. Glyphosate sorption was lower and biodegradation was slower under anaerobic conditions compared with aerobic, and most of the degraded glyphosate was not mineralized but cometabolized to AMPA.<br/><br> <br/><br> The thesis pin-points to the possibilities to increase contaminant biodegradation in aquifers by the addition of i) oxygen to stimulate aerobic degradation, ii) a primary growth substrate, e.g. DOM, to increase biomass and thereby stimulate metabolic or cometabolic degradation, and iii) microorganisms to increase the degrading population and/or genetic capacity.}}, author = {{Carlsson, Christel}}, isbn = {{91-7105-239-9}}, keywords = {{Ekologi; mycology; Mikrobiologi; Hydrobiology; biodegradation; Organic contaminants; redox conditions; sorption; DOM; cometabolism; biomass; microbial activity; microbial community composition; Ecology; Microbiology; bacteriology; virology; bakteriologi; mykologi; virologi; aquatic ecology; marine biology; limnology; Miljökemi; Environmental chemistry; akvatisk ekologi; Marinbiologi; limnologi}}, language = {{eng}}, publisher = {{Christel Carlsson, Department of Ecology, Chemical Ecology and Ecotoxicology, Lund University}}, school = {{Lund University}}, title = {{Limitations and possibilities for microbial degradation of organic contaminants in aquifers}}, year = {{2006}}, }