SCOPE 42 - Biogeochemistry of Major World Rivers

Preface

Rivers are the arteries of continents. They are the chief carriers of water, salt, organic matter, and mineral particles from land to sea. Continents on the other hand direct flow and composition of water in a number of ways. First, it is the height, the shape, and the direction of mountain chains in relation to the weather front, which determines the size and water potential of a catchment area. Second, rock type, climate, and vegetation give characteristic imprints on the chemistry of the dissolved and particulate load of a river system. And third, the impact of humans on quality and distribution of water is felt in an ever increasing fashion.

'Water is the best of all things.' This saying of Pindar (518-446 BC) has gained more and more momentum through the ages. Today, pristine water is hard to come by due to a growing world population and the excessive use of water in household, industry, and agriculture. Ground waters, rivers and lakes carry the alarming signals of human activities. Since such waters become recycled a number of times¾often without a proper 'reconvalescence' period¾pollutants will progressively invade our fresh water reserves from where they are eventually discharged to the estuaries and into the open sea.

Waters are analysed for various reasons and for this or that constituent practically everywhere. Lacking, however, is a long-term systematic study of major world rivers employing identical sampling procedures and analytical techniques plus a collection at short and synchronous intervals (2-4 weeks ) for: water run-off, pH, temperature, alkalinity, and the principal dissolved and particulate organic and inorganic constituents. Such work should continue for at least a decade, because a river is not a steady-state system, but governed by episodic events.

Ten years ago, and with the help of the SCOPE Community, we started an ambitious project entitled 'Transport of Carbon and Minerals in Major World Rivers', The aim of this study was the assessment of riverine discharge of water, dissolved and particulate organic matter, nutrients, and minerals into world ocean on local, regional and global scales. More than 100 scientists and technicians from about 20 countries became engaged in this venture. Thus, it is our pleasure to thank all participants from developing, threshold and industrialized nations for their strong engagement in carrying, under the leadership of SCOPE, the torch of environmental protection through their research efforts across borders and oceans.

  The original data have been published in an eight-volume series which were the outcome of SCOPE/UNEP International Workshops held since 1982: Hamburg, Fed. Rep. Germany (1982); Assyut, Egypt (1983); Caracas, Venezuela (1984); Tianjin, People's Republic of China (1985); Izmir, Turkey (1986); Fairbanks/Alaska, USA (1986); Texel, The Netherlands (1987); and Lake Baikal/Siberia, USA (1988): These volumes can be obtained from the SCOPE/UNEP International Carbon Unit, D-2000 Hamburg 13, 55 Bundesstrasse.

The present SCOPE Report Biogeochemistry of Major World Rivers is a kind of summary of the above volumes plus a brief review of regional and general aspects of river systems. In order to make the topic transparent, only a few coworkers were asked by the editors to write a chapter. However, all participants should really feel proud of having been a vital part of this team effort.

Throughout these years, the United Nations Environment Programme (UNEP) jointly with SCOPE encouraged our work on the rivers and we express our sincere gratitude to both organisations. The National SCOPE Committees, universities and research organisations deserve special thanks for financial support and encouragement in this endeavour.