This volume contains a selection of papers presented to the Fourth Internation~l Symposium on Environmental Biogeochemistry (ISEB), and a conference on Biogeochemistry in Relation to Mining Industry and Environmental Pollution (Leaching Conference), held in Canberra, Aust ralia on August 26-31 and September 3-4, 1979, respectively. The ISEB were established to provide "a forum for uninhibited exchange of information and ideas among the biological, chemical, atmospheric and geolorical scientists working in the common area of biogeochemistry, encompassing soil and other earth sciences as well as the hydrosphere and atmosphere", By linking the fourth ISEB with the Leachin~ Conference the scope of discussions was extended to encompass the application of biogeochemical processes to the mining industry. This wide-ranging philosophy is reflected in the breadth and diversity of the subjects covered in this book. The published papers are expanded versions of those presented at the meetings. They have all been scrutinized by at least one referee in addition to the editors. About 20% of the contributions to the meetings are not included, either because authors did not wish to publish or because the papers were not accepted by the editors.

This Special Issue of Water, Air, and Soil Pollution offers original contributions from BIOGEOMON, The Third International Symposium on Ecosystem Behavior, which was held on the campus ofVillanova University from June 21-25, 1997. Previous meetings were held in Prague in 1987 and again in 1993. The BIOGEOMON series was initiated in 1987 when a group of researchers from the Czech Geological Survey organized a conference called GEOMON, Geochemical Monitoring in Representative Basins. GEOMON was fairly narrowly focused on monitoring of element pools and fluxes on a small watershed scale. As signalled by the change in name to BIOGEOMON, the second conference explicitly recognized that assessment of anthropogenic effects on ecosystem processes requires a combination of geochemical monitoring with other approaches, including watershed-level manipulations, use of radioactive and stable isotopic tracers, and both empirical and process modeling. The 1997 BIOGEOMON conference was the largest, with over 240 participants from 28 countries on five continents in attendance, and broadest in scope. The conference featured a plenary speaker, six keynote speakers, 35 invited speakers, over 60 oral contributed presentations, and over 75 poster presentations.