Professor Emeritus, Soil Chemistry/Biochemistry, Iowa State University

Professor Emeritus, Colorado State University

Professor, The University of Queensland

Professor of Environmental Chemistry, Michigan State University

University of California, Merced

Department of Environmental Sciences, COMSATS University Islamabad (CUI) Vehari …

Professor , University of Sydney

Karlsruhe Institute of Technology (KIT), Institute of Geography and Geoecology

Bocock Chair for Agriculture and the Environment, University of Alberta

Retired