1. Centre for Research into Environment and Health, 5 Quakers Coppice, Crewe Gates Farm, Crewe, Cheshire, CW1 6FA, UK
2. Formerly of University of Leeds, Leeds, West Yorkshire, LS2 9JT, Currently: Atkins, Broadoak, Southgate Park, Bakewell Road, Orton Southgate, Peterborough, PE2 6YS, UK
3. River Basin Dynamics and Hydrology Research Groups, IGES, University of Wales, Aberystwyth, Ceredigion, SY23 2DB, UK
4. World Health Organization, Protection of the Human Environment, Geneva, Switzerland