Disputas: Pengxin Zhang

Prøveforelesning

Bedømmelseskomité

Professor Lars Rosén, Civil and Environmental Engineering, Chalmers University of Technology
Dr Helen French, Department of Plant and Environmental Sciences, Norwegian University of Life Sciences (UMB)
Professor Gijs Breedveld, Department of Geosciences, University of Oslo

Leder av disputas:  Professor Nils Roar Sælthun

Veileder:  Prof. Per Aagaard og Prof. Lars Gottschalk

Sammendrag

Contamination of groundwater is threatening the world's water resources and may thus undermine the basis of live on Earth. Once groundwater has been contaminated, it is very difficult or even impossible to clean it. So, it is important to predict the risk of contaminating groundwater, in order to impose measures to control or manage the risk.
In this PhD study, a reliability approach, namely the first order reliability method (FORM method), has been used to develop a probabilistic modelling of transport of contaminants in the subsurface. The approach is attractive because it can provide both a probability estimate of pollution spreading and probabilistic sensitivity measures. Sensitivity analysis is shown by the distribution of importance factors among variables, which can indicate their contribution to the failure probability. Hence, the authority can easily find which factors are most important in order to take action and reduce the risk of contamination.
Two main cases of groundwater pollution risk have been studied, namely pesticides in agricultural practice, and deicing chemicals and jet-fuel from airport activities. The thesis shows how the risk of pesticides being spread to the groundwater can be evaluated from soil concentrations in the field transport pathways and exposures to man and biota. The risk of polluting the groundwater from airport activities was done based on different spill/leakage scenarios, and expressed as failure probability. The uncertainty in the information about the various scenarios was also included. Both contaminant spreading through the soil down to groundwater and in the groundwater itself was considered.

Kontaktperson

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