1. Project Engineer, WJ Groundwater Ltd., 9 Park Rd., Bushey, Herts, WD23 3EE, U.K. E-mail: stevecox657@msn.com
2. Senior Research Fellow, Univ. of Southampton and Richard Beaven Associates Ltd., 17 Station Rd., Tollesbury, Essex, CM9 8RB, U.K. E-mail: richard.beaven@virgin.net
3. Head of School and Professor of Geotechnical Engineering, School of Civil Engineering and the Environment, Univ. of Southampton, Highfield, Southampton, SO17 1BJ, U.K. E-mail: wp@soton.ac.uk
4. Environmental Projects Manager, Cleanaway Ltd. Airborne Close, Arterial Rd., Leigh-on-Sea, Essex, SS9 4EL, U.K. E-mail: DarrenCole@cleanaway.com