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Multidisciplinary perspectives on a natural attenuation zone in a PCE-contaminated aquifer

Jansson, Robin LU (2018) In Dissertations in Geology at Lund University GEOR02 20172
Department of Geology
Abstract
The old dry-cleaner in Hagfors, is one of the most seriously tetrachloroethene (PCE) contaminated sites in Sweden. Ever since the pollution was discovered in the groundwater in the 1990s, the site has undergone remedi-ation two times with limited success. The Geological Survey of Sweden (SGU) has estimated that tens of tonnes of PCE are still left in the subsurface, where dissolved PCE is transported via groundwater and discharged to the adja-cent Örbäcken stream. In this study, I applied high-resolution direct current induced polarization (DCIP) and sam-pled the groundwater and the near-surface sediment for chloroethenes in a study area located adjacent to Örbäcken. The chemical results indicate that natural attenuation is an actively... (More)
The old dry-cleaner in Hagfors, is one of the most seriously tetrachloroethene (PCE) contaminated sites in Sweden. Ever since the pollution was discovered in the groundwater in the 1990s, the site has undergone remedi-ation two times with limited success. The Geological Survey of Sweden (SGU) has estimated that tens of tonnes of PCE are still left in the subsurface, where dissolved PCE is transported via groundwater and discharged to the adja-cent Örbäcken stream. In this study, I applied high-resolution direct current induced polarization (DCIP) and sam-pled the groundwater and the near-surface sediment for chloroethenes in a study area located adjacent to Örbäcken. The chemical results indicate that natural attenuation is an actively ongoing process in the study area, while the DCIP model result provided information about subsurface structures that correlate well with the aquifer-aquitard boundary indicated from already existing core descriptions. The different DCIP model results were displayed to-gether with borehole data, as well as chemical reference data, in a 3D model. These combined results clearly showed two structures that are continuous throughout the study area. These two structures include one zone of high resistivity, correlating with an area of high amount of the biological degradation product cis-1.2-dichloroethene (cisDCE), and the other is a tilted zone with low resistivity upstream of the high-resistivity zone. The low-resistivity tilted zone crosses the aquifer-aquitard boundary and is interpreted as a fracture zone in the aquitard.

The work is part of the research project Monitoring of In situ RemediAtion of CHLorinated hydrocarbon contami-nants, MIRACHL (Funder by Formas 2016-00808 and 942-2016-99, SGU and Tyréns Stiftelse).The work was also partly supported by the European Union, Eurostars Programme, together with Innovation Fund Denmark and The Swedish innovation agency Vinnova under the project “Mapping Geology in Cities” (E10096 MAGIC). (Less)
Popular Abstract (Swedish)
Den gamla kemtvätten i Hagfors är ett av de kraftigast tetrakloreten (PCE) förorenade områdena i Sverige. Sedan föroreningen upptäcktes i grundvattnet på 1990-talet har området genomgått två saneringar med begränsad framgång. Sveriges Geologiska Undersökning (SGU) har uppskattat att tiotals ton PCE fortfarande finns kvar under markytan. Upplöst PCE transporteras i grundvattensystemet och läcker sedan ut i den närliggande Ör-bäcken. Området som undersökts inom ramen för detta examensarbete ligger alldeles intill Örbäcken. Den geofy-siska metoden DCIP (Direct Current Induced Polarization) har använts högupplöst inom området, tillsammans med provtagning av grundvatten och ytnära sediment, som analyserats med avseende på kloreteninnehåll. De... (More)
Den gamla kemtvätten i Hagfors är ett av de kraftigast tetrakloreten (PCE) förorenade områdena i Sverige. Sedan föroreningen upptäcktes i grundvattnet på 1990-talet har området genomgått två saneringar med begränsad framgång. Sveriges Geologiska Undersökning (SGU) har uppskattat att tiotals ton PCE fortfarande finns kvar under markytan. Upplöst PCE transporteras i grundvattensystemet och läcker sedan ut i den närliggande Ör-bäcken. Området som undersökts inom ramen för detta examensarbete ligger alldeles intill Örbäcken. Den geofy-siska metoden DCIP (Direct Current Induced Polarization) har använts högupplöst inom området, tillsammans med provtagning av grundvatten och ytnära sediment, som analyserats med avseende på kloreteninnehåll. De kemiska resultaten indikerar att naturlig nedbrytning av PCE och dess nedbrytningsprodukter är en aktivt pågående process inom undersökningsområdet. De geofysiska resultaten ger information om en yta som korrelerar väl med akvifär-akvitardgränsen. Genom att kombinera DCIP-resultaten med borrhålsdata och kemiska referensdata, har en 3D-modell konstruerats. De kombinerade resultaten visar tydligt två avvikande zoner. En av zonerna uppvisar hög resistivitet, samtidigt som höga halter nedbrytningsprodukter (cisDCE) detekterats i zonen. Den andra zonen är en lutande lågresistiv zon, belägen uppströms zonen med hög resistivitet. Den lågresistiva zonen bryter akvifärs-akvitardgränsen, och tolkas som en sprickzon i akvitarden.

Arbete ingår i forskningsprojektet Monitoring of In situ RemediAtion of CHLorinated hydrocarbon contaminants, MIRACHL (Finansierat av Formas 2016-00808 samt 942-2016-99, SGU och Tyréns Stiftelse). Arbetet stöddes också delvis av Europeiska Unionen, Eurostar Programme, tillsammans med Innovation Fund Denmark och Vin-nova i projektet ”Mapping Geology in Cities” (E10096 MAGIC). (Less)
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author
Jansson, Robin LU
supervisor
organization
course
GEOR02 20172
year
type
H2 - Master's Degree (Two Years)
subject
keywords
DCIP, groundwater chemistry, Tetrachlorethene, PCE, natural attenuation
publication/series
Dissertations in Geology at Lund University
report number
528
funder
Vinnova
funder
Swedish Geological Survey
funder
FORMAS
funder
Sven Tyrén Trust
funder
The Eurostars programme
funder
Innovation Fund Denmark
language
English
additional info
The work is part of the research project Monitoring of In situ RemediAtion of CHLorinated hydrocarbon contami-nants, MIRACHL (Funder by Formas 2016-00808 and 942-2016-99, SGU and Tyréns Stiftelse). The work was also partly supported by the European Union, Eurostars Programme, together with Innovation Fund Denmark and The Swedish innovation agency Vinnova under the project “Mapping Geology in Cities” (E10096 MAGIC).
id
8940579
date added to LUP
2018-05-21 10:40:55
date last changed
2020-05-18 15:23:39
@misc{8940579,
  abstract     = {The old dry-cleaner in Hagfors, is one of the most seriously tetrachloroethene (PCE) contaminated sites in Sweden. Ever since the pollution was discovered in the groundwater in the 1990s, the site has undergone remedi-ation two times with limited success. The Geological Survey of Sweden (SGU) has estimated that tens of tonnes of PCE are still left in the subsurface, where dissolved PCE is transported via groundwater and discharged to the adja-cent Örbäcken stream. In this study, I applied high-resolution direct current induced polarization (DCIP) and sam-pled the groundwater and the near-surface sediment for chloroethenes in a study area located adjacent to Örbäcken. The chemical results indicate that natural attenuation is an actively ongoing process in the study area, while the DCIP model result provided information about subsurface structures that correlate well with the aquifer-aquitard boundary indicated from already existing core descriptions. The different DCIP model results were displayed to-gether with borehole data, as well as chemical reference data, in a 3D model. These combined results clearly showed two structures that are continuous throughout the study area. These two structures include one zone of high resistivity, correlating with an area of high amount of the biological degradation product cis-1.2-dichloroethene (cisDCE), and the other is a tilted zone with low resistivity upstream of the high-resistivity zone. The low-resistivity tilted zone crosses the aquifer-aquitard boundary and is interpreted as a fracture zone in the aquitard.

The work is part of the research project Monitoring of In situ RemediAtion of CHLorinated hydrocarbon contami-nants, MIRACHL (Funder by Formas 2016-00808 and 942-2016-99, SGU and Tyréns Stiftelse).The work was also partly supported by the European Union, Eurostars Programme, together with Innovation Fund Denmark and The Swedish innovation agency Vinnova under the project “Mapping Geology in Cities” (E10096 MAGIC).},
  author       = {Jansson, Robin},
  keyword      = {DCIP,groundwater chemistry,Tetrachlorethene,PCE,natural attenuation},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Multidisciplinary perspectives on a natural attenuation zone in a PCE-contaminated aquifer},
  year         = {2018},
}