Industrial Metabolism and River Basin Studies: A New Approach for the Analysis of Chemical Pollution

The object of this report is to demonstrate the merit of studies in industrial metabolism as a new analytical tool for assessing the sources and flows of toxic chemicals. The methodology provides a framework for "cradle-to-grave" analysis that traces the movement of chemicals through the industrial economy, identifies the entry points through which they pass from the economy to the environment, and assesses their impact once they have entered the environment. The analysis is guided throughout by the simple constraint imposed by the principle of mass balance, which requires that the sum total of a chemical remains constant as it moves through a system from production to consumption to disposal, even as the partitioning of the chemical into various economic streams changes. Much of the analysis in this report is focused on the Rhine River Basin. The authors suggest that the spatial unit of large river basins may be ideal for studies in industrial metabolism. By definition, a river basin encompasses the land area that drains into the rivers or its tributaries. Thus, if one accounts for movements of materials into or out of the basin (particularly via atmospheric transport), it may be assumed that emissions generated within the basin can be lost from the basin only by river transport and discharge at its mouth. The remainder of the emissions (equal to total emissions minus the output from the basin) is deposited in and spatially bound by the basin, accumulating in chemical sinks, including agricultural soils, ground waters, sediments of lakes and tributaries, and landfills and toxic waste dumps. Mass balance analysis ensures that these sinks are accounted for and provides boundary conditions for assessing cumulative loads. Moreover, the tracing of chemical flows, both in the economy and environment occurs within the same spatial domain, and linkages between sources and their environmental effects are more easily established.