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Abstract
The access to safe drinking water is essential for the well being of the population.
The spread of micropollutant contamination jeopardise many freshwater reservoirs,
and is a serious threat for human health, especially because of its long-term effects.
To asses the threat of contamination, models are required to study the main contamination
pathways, and to make predictions of pollution fluxes. Groundwater is
used as drinking water in many countries because subsurface processes can mitigate
pollution and purify the water by removing xenobiotic compounds. However,
groundwater often interacts with surface water, which is more vulnerable to contamination,
and can transfer pollution to groundwater.
The fate of micropollutants in aquifers is influenced by many factors: sorption,
degradation and dilution are processes that can interact together and create very
complex systems, which are difficult to model. The identification of dominant
processes is an essential step in the understanding of system behaviour, because
it enables the development of simplified models that can approximate the fate of
contaminants with the best trade-off between model complexity and reliability of
results. In this thesis, global sensitivity analysis techniques are used to assess detailed
models in order to identify the main processes involved in the degradation
of chlorinated solvents in the subsurface, and in the transport of pesticides from
surface water into nearby wells in confined aquifers. Statistical techniques are also
employed to identify large-scale contamination processes by examining observations
of contamination in drinking water wells in Zealand, Denmark.
Results show that persistent compounds in surface water can leach into nearby
pumping wells even if an impermeable clay layer overlies the well screen. Thus
aquitards may not provide adequate protection against contamination by micropollutants
in surface water, as generally thought. Results also show that the fermentation
of organic compounds and the sulphate concentration in groundwater govern
the success of sequential reductive dechlorination in aquifers, and that the simulation
of chlorinated aliphatic hydrocarbon degradation cannot be approximated by
simple models without losing the ability to simulate important system behaviour.
The statistical analysis of contaminant concentrations in Danish drinking water
wells demonstrates that drinking water well contamination by BAM, a pesticide
metabolite, is mainly a problem in urban areas, and that in Zealand, wells close to
surface water are generally more vulnerable to pesticide contamination.
Original language | English |
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Place of Publication | Kgs. Lyngby, Denmark |
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Publisher | Technical University of Denmark |
Number of pages | 41 |
ISBN (Print) | 978-87-92654-43-4 |
ISBN (Electronic) | 978-87-92654-44-1 |
Publication status | Published - 2011 |
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Dive into the research topics of 'Models and statistical analysis of organic micropollutants in groundwater-based drinking water resources'. Together they form a unique fingerprint.Projects
- 1 Finished
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Determining the impact of point sources of contamination on groundwater based drinking water resources
Malaguerra, F. (PhD Student), Binning, P. J. (Main Supervisor), Albrechtsen, H.-J. (Supervisor), Bauer-Gottwein, P. (Examiner), van Breukelen, B. (Examiner) & Kjaer, J. (Examiner)
15/06/2008 → 21/09/2011
Project: PhD