Deposition of heavy metals to the Convention waters of OSPARCOM

The atmospheric transport model EUTREND of RIVM was used to calculate the transport and deposition of the heavy metals on the Convention waters. Results were obtained for the Regions II, III and IV (respectively Greater North Sea, Celtic Sea and Bay of Biscay and Iberian Coast) and part of Regions I (Arctic Waters) and V (Wider Atlantic). The contributions from 5 source categories to the deposition on (Sub) Regions were calculated: 1. stationary combustion, 2. mobile sources, 3. primary iron and steel production, 4. non-ferrous metal industry and 5. others.

The contribution of the OSPARCOM countries to the deposition on the Convention waters as well as the contribution by the non-OSPARCOM countries as a whole were calculated. Measured air concentrations are underestimated by the calculations by a factor of 2-4 for nickel, cadmium , copper, chromium and zinc. For lead the comparison was close to the 1:1 line. The underestimations are most likely due to an underestimation of the emissions. A comparison between the input of heavy metals by atmospheric deposition and riverine input around the North Sea as well as a comparison with other studies on the atmospheric input to the North Sea estimated from measurements and modelling are presented.