This volume brings together a number of papers, some of which were originally presented to the 3rd Consultative Meeting of Research and Training Institutions held in Guam in June 1986. Also included are papers derived from related work undertaken by scientists of the University of Papua New Guinea as part of their research programmes. Financial support for these studies was derived from various sources including the United Nations Environment Programme (UNEP via the South Pacific Regional Environment Programme (SPREP), and the University of Papua New Guinea Research Committee. These papers represent an important contribution in that they document the state of the environment prior to the commencement of mining at the large Ok Tedi gold and copper mine In particular the papers dealing with the Lakes of the middle Fly region represent the sole base-line data for these systems. Ongoing work as part of the SPREP work programme for 1986-1988 is designed to establish what changes if any are detectable in the Fly River and Delta, following the onset of copper production.