Assessment of the Applicability for Pollution Control Authorities of the Concept "Critical loads" of Long range Transported Micropollutants in Relation to Aquatic and Terrestrial Ecosystems

Abstract

The applicability for pollution management and control authorities of consept "Critical load" of long-range transported micropollutants has been evaluated for sensitive parts of aquatic and terrestrial ecosystems. The background for this assessment is the previous sucessful use of the critical load approach in international negotiations aiming at the reduction of acid precipitation components. The review of discharge and deposition data for micropollutants showed that this information was inadequate to calculate load with sufficient accuracy except for lead (and possibly cadmium). The reviews about observed effects in Norwegian water, soil, terrestrial and Arctic environments all concluded that effects on population levels from long-range transported persitent organic and metals could not be documented so far. As and alternative approach in international negotiations to reduce spreading of micropollutants it is recommended to use the precautionary principle. It is recommended to increase efforts in mapping of discharge and deposition of micropollutants and to give high priority to effect studies, in particular with regard to critical doses and critical concentrations in exposure media and organisms.