Weighting of environmental impacts is necessary to arrive at a single environmental indicator. One of the methods to weigh impacts, which has been operationalised for a number of impact categories in the Netherlands, is known as the shadow price method, using the highest acceptable costs for mitigation measures as a weighting factor. Up to now, no shadow prices were available for the more complex and less documented Environmental Impact Categories (EICs) in the field of human toxicity, ecotoxicity and depletion of abiotic materials. Therefore, a method was developed and applied to assess the shadow prices of these EICs. It consists of four steps: (1) characterising current environmental policy; (2) concentrating on the most relevant substances; (3) collecting abatement cost data and (4) calculating the shadow price.
The paper describes the method, discusses the results and concludes by presenting the full set of shadow prices in the Netherlands for the ten EICs of the CML-2 method. They are ready to be applied in the assessment of environmental profiles and the evaluation of measures in cost–benefit analysis, according to present policy preferences. We show that the external costs of the toxicity impact categories are, on average, substantial compared to those of the EICs for which shadow prices had already been established.