Evaluation of risks of metal flows and accumulation in economy and environment

The contrast between, on the one hand, decreasing emissions of the metals cadmium, copper, lead and zinc and, on the other, their continuously increasing input into the economy is analysed for three case studies: The Netherlands as a whole, the Dutch housing sector and the Dutch agricultural sector. Flows of these metals through and their accumulation within the economy and the environment have been quantified for 1990 and for a constructed steady-state situation. To this end, the substance flow analysis method has been applied. The case studies show that there is a strong increase to be expected in the emissions from the 1990 to the steady-state situation. This increase is mainly due to the shift from landfill accumulation to emission to non-agricultural soil. At the same time, however, there is also an increase in the emissions to other media: air, water and agricultural soil. Emissions along these critical routes with respect to human and ecotoxicity show an approximately 30% increase for cadmium, lead and zinc and more than a doubling for copper. It is shown that this increase may lead to the surpassing of critical levels for human toxicity and terrestrial and aquatic ecotoxicity. Some possible measures are suggested to prevent critical levels being exceeded.