『Abstract
　This paper illustrates how sensitivity analysis and a worst-case scenario analysis can be useful tools in risk assessment of groundwater pollution. The approach is applied to a study area in Hungary with several known groundwater pollution sources and nearby drinking water production wells. The main concern is whether the contamination sources threaten the drinking water wells of the area. A groundwater flow and transport model is set up to answer this question. Due to limited data availability, the results of this model are associated with large uncertainty. Sensitivity analysis and a worst-case scenario analysis are applied to estimate this uncertainty and build confidence in the model results.

Keywords: Sensitivity analysis; Worst-case scenario analysis; Groundwater pollution; Groundwater and transport modeling』

Introduction
Geology
Groundwater flow model
　Boundary conditions
　Grid
　Hydraulic conductivity
　Calibration
　Results
Transport simulation
　Boundary conditions
　Transport parameters
　Results
Sensitivity analysis
A worst-case scenario analysis
Discussion and conclusion
References

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