Environmental Geochemistry on a Global Scale

Abstract

Recent population growth and economic development are extending the problems associated with land degradation, pollution, urbanization, and the effects of climate change over large areas of the earth’s surface, giving increasing cause for concern about the state of the environment. Many problems are most acute in tropical, equatorial, and desert regions where the surface environment is particularly fragile because of its long history of intense chemical weathering over geological timescales. The speed and scale of the impact of human activities are now so great that, according to some authors, for example, McMichael (1993), there is the threat of global ecological disruption. Concern that human activities are unsustainable has led to the report of the World Commission on Environment and Development Our Common Future (Barnaby 1987) and the establishment of a United Nations Commission on Sustainable Development responsible for carrying out Agenda 21, the action plan of the 1992 Earth Summit in Rio de Janeiro, Brazil. Considerable research into the global environment is now being undertaken, especially into issues such as climate change, biodiversity, and water quality. Relatively little work has been carried out on the sustainability of the Earth’s land surface and its life support systems, however, other than on an ad-hoc basis in response to problems such as mercury poisoning related to artisanal gold mining in Amazonia or arsenic poisoning as a result of water supply problems in Bangladesh (Smedley 1999). This chapter proposes a more strategic approach to understanding the distribution and behavior of chemicals in the environment based on the preparation of a global geochemical baseline to help to sustain the Earth’s land surface based on the systematic knowledge of its geochemistry. Geochemical data contain information directly relevant to economic and environmental decisions involving mineral exploration, extraction, and processing; manufacturing industries; agriculture and forestry; many aspects of human and animal health; waste disposal; and land-use planning. A database showing the spatial variations in the abundance of chemical elements over the Earth’s surface is, therefore, a key step in embracing all aspects of environmental geochemistry. Although environmental problems do not respect political boundaries, data from one part of the world may have important implications elsewhere.