Critical loads for lead (Pb) and cadmium (Cd) in surface waters in Norway - evaluation of methodology and preliminary maps

Abstract

Critical loads for lead (Pb) and cadmium (Cd) are calculated for Norwegian surface waters based on currently available methodology from the UNECE ICP Mapping and Modelling program. Two different values are used for critical limits. Using the critical limits recommended in the Mapping Manual the critical loads are high, well above the current deposition in Norway. Using critical limits from the lowest part of the range suggested, however, the critical loads are of similar size as current deposition. We also calculated the so called stand still loads, where the criteria is no increase in current concentration rather than a biological effect. The stand still loads are very low, for Cd in many cases 0, and usually lower than the current deposition.