What technologies have proved to be effective? What needs to be improved? What are the innovations and how promising are they? Is there room or need for extensive R&D programmes? How willing are international or local contractors to use innovative technologies? What are the risks? The business factor can be measured in terms of inexpensive vs costly technolo­gies (e. g., in-situ measurements vs. laboratory analysis). How to optimize the relationship between costs and accuracy of measurements? ER plan­ning depends heavily on predictions about the behaviour of pollutants in different compartments (soil, groundwater, etc.) as well as on the design of remediation solutions. What are the challenges in mathematical models? How effectively and wisely are these being used? How to best educate and give training to potential modellers? What role does statistics play in pre — and post-clean-up characterization in reducing costs while ensuring safety?