Instrumentation of multilevel systems with transducers to characterize hydrogeological conditions at a PCE and TCE contaminated site in Helsingborg, Sweden
(2025) In Dissertations in Geology at Lund University GEOR02 20231Department of Geology
- Abstract
- High-detailed data are key when characterizing complex contaminated sites. In this study we instrument Star-Oddi milli-TD pressure transducers in G360 multilevel groundwater monitoring systems within a mainly PCE (tetrachloroethylene) and TCE (trichloroethylene) contaminated residential area in Helsingborg, Sweden. Despite these transducers being typically utilized in marine research, their affordability and compact size render them of interest to multilevel applications. A part of this study is therefore dedicated to evaluating their performance in monitoring spatiotemporal hydraulic head variability in multilevel systems. We integrate the transducer data with previously gathered contaminant concentration levels to estimate... (More)
- High-detailed data are key when characterizing complex contaminated sites. In this study we instrument Star-Oddi milli-TD pressure transducers in G360 multilevel groundwater monitoring systems within a mainly PCE (tetrachloroethylene) and TCE (trichloroethylene) contaminated residential area in Helsingborg, Sweden. Despite these transducers being typically utilized in marine research, their affordability and compact size render them of interest to multilevel applications. A part of this study is therefore dedicated to evaluating their performance in monitoring spatiotemporal hydraulic head variability in multilevel systems. We integrate the transducer data with previously gathered contaminant concentration levels to estimate hydrogeological properties of the contaminated zones and evaluate the range in contaminant migration and plume mass discharge across a transect 100 m down-gradient from the persistent DNAPL source zone. Vertical profiles of hydrographs from depth-discrete monitoring intervals were produced and vertical gradients were calculated for each multilevel to identify potential hydrogeological units (HGUs). Two HGU boundaries at 11 m asl and 18 m asl, as well as two deeper potential boundaries, were identified. The potentiometric surface for the shallowest HGU indicates groundwater flow towards approximately 290° (from the geographic north). The contaminant plume, however, migrates toward approximately 235°. The discrepancy in groundwater flow directions may be due to channelized flow induced by transmissive fractures. The discharge across the transect ranges from 0.068 to 0.081 kg PCE equivalents/year, and the PCE and TCE plume lengths were estimated to be up to 0.5 and 1.4 km respectively using sorption as the retarding factor. The transducers’ performance proved adequate, although some issues were observed including varyingly lagged step change responses consecutive to deployment which lasted up to several days for certain transducer data. Still, this study shows that utilizing unconventional transducers can reduce the cost of high-resolution spatiotemporal groundwater monitoring. For future work, the plume length should be thoroughly delineated, which is why we recommend installing additional monitoring wells 100 m downgradient of the current transect as well as refining the plume length calculations by incorporating diffusion as an additional retarding factor. (Less)
- Abstract (Swedish)
- Detaljerade data är avgörande vid karaktärisering av komplexa förorenade områden. I denna studie utrustar vi ett antal G360-brunnssystem med Star-Oddi milli-TD-tryckgivare i ett mestadels PCE (tetrakloretylen)- och TCE (trikloretylen)-förorenat bostadsområde i Helsingborg. Trots att dessa tryckgivare vanligtvis används inom marina undersökningar gör deras kostnad samt kompakta storlek dem av intresse för användning i dessa brunnssystem. En del av denna studie ägnas därför åt att utvärdera deras prestanda vid mätning av tids- och rumslig vattennivåvariation i brunnssystemen. Vi integrerar tryckgivardata med tidigare mätta föroreningshalter i syfte att uppskatta hydrogeologiska egenskaper inom hela den förorenade zonen och utvärdera... (More)
- Detaljerade data är avgörande vid karaktärisering av komplexa förorenade områden. I denna studie utrustar vi ett antal G360-brunnssystem med Star-Oddi milli-TD-tryckgivare i ett mestadels PCE (tetrakloretylen)- och TCE (trikloretylen)-förorenat bostadsområde i Helsingborg. Trots att dessa tryckgivare vanligtvis används inom marina undersökningar gör deras kostnad samt kompakta storlek dem av intresse för användning i dessa brunnssystem. En del av denna studie ägnas därför åt att utvärdera deras prestanda vid mätning av tids- och rumslig vattennivåvariation i brunnssystemen. Vi integrerar tryckgivardata med tidigare mätta föroreningshalter i syfte att uppskatta hydrogeologiska egenskaper inom hela den förorenade zonen och utvärdera räckvidden av föroreningsplymen samt dess masspridning genom ett tvärsnitt 100 m nedströms källzonen. Vertikala profiler av trycknivåskillnader med djupet och vertikala gradienter beräknades för varje brunnssystem för att avgränsa potentiella hydrogeologiska enheter. Två gränser vid 11 och 18 m.ö.h., samt två potentiella djupare gränser, identifierades. Den potentiometriska ytan för den grundaste enheten indikerar ett grundvattenflöde åt ca 290° (från den geografiska nordpolen). Föroreningsplymen migrerar dock åt cirka 235°. Skillnaden i grundvattnets flödesriktning kan bero på riktat flöde i genomsläppliga sprickor. Masspridningen genom tvärsnittet varierar från 0,068 till 0,081 kg PCE-ekvivalenter/år, och PCE- samt TCE-plymernas längd uppskattas till 0,5 respektive 1,4 km baserat på sorption som den bromsande faktorn. Tryckgivarna presterade funktionsdugligt, även om vissa problem observerades så som en varierat fördröjd respons som uppkom i samband med installationen och som varade i flera dagar för vissa tryckgivardata. Med det sagt visar denna studie att användandet av icke traditionella tryckgivare kan minska kostnaden för högupplöst grundvattenövervakning. I framtida arbeten bör plymlängden noggrant avgränsas, varför vi rekommenderar att ytterligare observationsbrunnar installeras 100 m nedströms det nuvarande tvärsnittet samt att längdberäkningarna av plymen justeras baserat på diffusion som en ytterligare bromsande faktor. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9183925
- author
- Johansson, Robin LU
- supervisor
- organization
- course
- GEOR02 20231
- year
- 2025
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- transducer, multilevel system, PCE, TCE, DNAPL, gradient, fracture, discharge tryckgivare, flernivåsystem, spricka, masspridning
- publication/series
- Dissertations in Geology at Lund University
- report number
- 698
- language
- English
- Swedish
- additional info
- External supervisor: Beth L. Parker, UoG & G360
- id
- 9183925
- date added to LUP
- 2025-02-04 09:44:46
- date last changed
- 2025-02-04 09:44:46
@misc{9183925,
abstract = {{High-detailed data are key when characterizing complex contaminated sites. In this study we instrument Star-Oddi milli-TD pressure transducers in G360 multilevel groundwater monitoring systems within a mainly PCE (tetrachloroethylene) and TCE (trichloroethylene) contaminated residential area in Helsingborg, Sweden. Despite these transducers being typically utilized in marine research, their affordability and compact size render them of interest to multilevel applications. A part of this study is therefore dedicated to evaluating their performance in monitoring spatiotemporal hydraulic head variability in multilevel systems. We integrate the transducer data with previously gathered contaminant concentration levels to estimate hydrogeological properties of the contaminated zones and evaluate the range in contaminant migration and plume mass discharge across a transect 100 m down-gradient from the persistent DNAPL source zone. Vertical profiles of hydrographs from depth-discrete monitoring intervals were produced and vertical gradients were calculated for each multilevel to identify potential hydrogeological units (HGUs). Two HGU boundaries at 11 m asl and 18 m asl, as well as two deeper potential boundaries, were identified. The potentiometric surface for the shallowest HGU indicates groundwater flow towards approximately 290° (from the geographic north). The contaminant plume, however, migrates toward approximately 235°. The discrepancy in groundwater flow directions may be due to channelized flow induced by transmissive fractures. The discharge across the transect ranges from 0.068 to 0.081 kg PCE equivalents/year, and the PCE and TCE plume lengths were estimated to be up to 0.5 and 1.4 km respectively using sorption as the retarding factor. The transducers’ performance proved adequate, although some issues were observed including varyingly lagged step change responses consecutive to deployment which lasted up to several days for certain transducer data. Still, this study shows that utilizing unconventional transducers can reduce the cost of high-resolution spatiotemporal groundwater monitoring. For future work, the plume length should be thoroughly delineated, which is why we recommend installing additional monitoring wells 100 m downgradient of the current transect as well as refining the plume length calculations by incorporating diffusion as an additional retarding factor.}},
author = {{Johansson, Robin}},
language = {{eng}},
note = {{Student Paper}},
series = {{Dissertations in Geology at Lund University}},
title = {{Instrumentation of multilevel systems with transducers to characterize hydrogeological conditions at a PCE and TCE contaminated site in Helsingborg, Sweden}},
year = {{2025}},
}