P.P.A.A.H. Kandelaars

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.

Materials-product chains: Theory and an application to zinc and PVC gutters

A framework is presented for the analysis of economic and environmental impacts of policies applied to materials-product (MP) chains. This is based on materials flows, product flows, costs, prices and optimal management of an MP chain. The main differences compared with other studies focusing on materials flows is that here the link between products or services and materials is explicitly dealt with. The framework is developed on the basis of materials balance conditions, production functions allowing for substitution, and recycling of both materials and products. After presenting theoretical MP chain-models and analytical results, an application to the problem of choosing between zinc and PVC gutters is discussed. Here optimal MP chain management decisions are presented for various policy and strategy scenarios.

A Dynamic Simulation Model For Materials-Product-Chains: An Application to Gutters

A descriptive dynamic model is presented to study the impacts of various policies aimed at reducing the use of materials in materials-product-chains (M-P chains). An M-P chain describes the flows of materials and products on a physical and a monetary level to allow assessments of strategies affecting both material and economic characteristics. Recycling and substitution are included in the model, which is applied to gutters and associated materials flows of zinc and polyvinyl chloride. Economic and material impacts of several scenarios are assessed.

Result of the scenario calculations

In this section the developed models presented in Part II are applied to calculate the impacts of the scenarios as described in Section IV.2. In IV.3.1 the FLUX — Dynabox combination in its dynamic mode is applied to the flows and stocks of copper and zinc in the Netherlands. Section IV.3.2 is dedicated mainly to the issue of stock modelling, which appears to be quite complicated and also very important for dynamic modelling. In Section IV.3.3 MPC modelling is applied to a specific materials-product chain: zinc gutters. This serves as an illustration of issues of costs and implementation, which are ignored by FLUX. Finally, in Section IV.3.4, the D[SC]B model is applied to calculate the copper and zinc concentrations in agricultural soils resulting from the assumed changes.

Applications of Material-Product Chain analysis

The diversity of potential approaches and applications of M-P chain analysis is illustrated here by discussing five specific applications (for a more comprehensive overview, see Kandelaars 1998). Each of the applied models combines elements of both physical flow and economic models in a particular way. It is important to know what model type to use for which purpose. The main focus of the applications A to D is the demand for a service that may be met with different products (partial), while in application E the whole economy, including production sectors and household groups is allowed to change (general). Table III.2.1 shows which type of models have been used in the applications discussed in this section, as well as which “pure model types” of Table III.2.1 they integrate.

Economic analysis of Material-Product Chains

Physical aspects of environmental problems are studied by natural and environmental scientists. However, their studies usually do not consider the economic and behavioural mechanisms underlying physical processes and material flows in the economy. In policy design, physical and technological possibilities need to be combined with economic aspects and behaviour. Traditionally, environmental economics has mainly focused on a partial analysis of environmental problems, resulting in a neglect for the interdependence of environmental problems caused by different economic stages. Often environmental economics focuses on external effects, without considering the material or physical dimension of problems. Economic processes are linked to — and even regarded as embedded in — physical processes and therefore a change in an economic process affects the physical process and vice versa. To include this physical dimension, material flow models may be combined with economic models. This allows the study of policy packages in which physical and economic aspects are considered simultaneously. This results in analyses that are economically consistent and physically feasible.