Atmospheric supply of nitrogen, lead, cadmium, mercury and dioxins/furans to the Baltic Sea in 2005

	Authors: Jerzy Bartnicki - MSC-W of EMEP e-mail: jerzy.bartnicki@met.no Alexey Gusev - MSC-E of EMEP e-mail: alexey.gusev@msceast.org Wenche Aas - CCC of EMEP e-mail: wenche.aas@nilu.no Hilde Fagerli - MSC-W of EMEP e-mail: hilde.fagerli@met.no

Summary

The results presented in this EMEP Centres Joint Report for HELCOM are based on the modelling and monitoring data presented to the 31th Session of the Steering Body of EMEP in Geneva in September 2007. It includes measurements, as well as emissions and depositions calculated by the EMEP models of nitrogen compounds, heavy metals and PCDD/F for the year 2005.

The measured monthly and annual 2005 concentrations in air and precipitation for nitrogen species, heavy metals, as well as air concentrations for lindane are presented in the report. Both for nitrogen and heavy metals a significant south-east gradient can be noticed in the measured concentrations in 2005. The temporal patterns of monthly Cd and Pb concentrations show a strong winter maximum and temporal pattern of Hg monthly concentrations weaker wintermaxim. During winter the atmospheric residence time is longer due to reduced vertical mixing.

Annual emissions from the HELCOM Contractig Parties in 2005 are shown below for all pollutants considered in the report. The annual nitrogen oxides emission from the international ship traffic on the Baltic Sea in 2005 is 343kt NO₂ (or 104 kt N).

Compared to 2004 emissions, annual emissions in 2005 are slightly lower for almost all pollutants except NO₂ ship emissions on the Baltic Sea which are 2.5% higher.

Annual depositions of all considered pollutants in 2005 are shown in the Table below for 6 sub-basins of the Baltic Sea and for the entire Baltic Sea.

Nitrogen depositions followed the nitrogen emission changes and were lower in 2005 than in 2004 in most of sub-basins and in the entire Baltic Sea Basin. Depositions of heavy metals to the entire Baltic Sea remain on the same level in 2005 as in 2004, but there are some differences in distributions among sub-basins. Deposition of PCDD/F to the entire Baltic Sea is approximately 6% higher in 2005 than in 2004. There is also an increase of PCDD/F deposition from 2004 to 2005 for most of the sub-basins.

This report has been prepared for the Helsinki Commission (HELCOM), Baltic Marine Environment Protection Commission, based on the model estimates and monitoring results which have been presented to the thirty first session of the Steering Body of EMEP (Co-operative Programme for Monitoring and Evaluation of Long-Range Transmission of Air Pollutants in Europe). This present, ninth joint summary report for HELCOM includes the measurements and results of modelling in the Baltic Sea region for oxidized nitrogen, reduced nitrogen, lead, cadmium, mercury and dioxins/furans for the year 2005. It has been developed in a frame of close collaboration between three modelling and monitoring EMEP centres: MSC-W, MSC-E and CCC, and is available now on the EMEP WEB pages and later on the HELCOM WEB pages. The report, as a draft, was presented and discussed at the Tenth MONAS Meeting (2-6/10/2007) in Helsinki Finland, together with corresponding drafts of the Indicator Fact Sheets. Participants of this meeting were asked for the comments and corrections which are taken into account in the present final version of the report and Indicator Fact Sheets, as well. All comments/corrections received form the HELCOM Parties are listed on this site.

Acknowledgements

The authors are indebted to the scientific teams at MSC-E, MSC-W and CCC for providing the results included in this report and especially to Per Helmer Skaali for his help with the Internet related tasks. We are grateful to Ms. Marina Varygina, Dr. Ilia Iliyn and Prof. Victor Shatalov for their contribution to this work, valuable remarks and comments.