Atmospheric supply of nitrogen, lead, cadmium, mercury and dioxins/furans to the Baltic Sea in 2010

	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 Semeena Valiyaveetil - MSC - W of EMEP e-mail: semeena.valiyaveetil@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 36th Session of the Steering Body of EMEP in Geneva in September 2012. 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 2010.

The measured monthly and annual 2010 concentrations in air and precipitation for nitrogen species and heavy metals are presented in the report. For most components a significant south-east gradient can be noticed in the measured concentrations in 2010, except for NO2 which have highest levels in East and West. Further the concentration levels seem to be higher in southwest than southeast for the nitrogen components, maybe due to influence of the extensive traffic (ship as well as cars) and agricultural activities in this region.

The temporal patterns of monthly Cd and Pb concentrations in air show a winter maximum, similar tendency for elemental Hg. Also total nitrate concentration in air show elevated levels in the spring and generally higher concentrations in winter than summer. Concentrations of NO2 show a clear winter maxima/summer minima. These elevated concentrations in winter occur probably due to longer atmospheric residence time and reduced vertical mixing. Reduced nitrogen in air has maximum in spring when the fertilizing is most important. The seasonal patterns in precipitation are not as strong as for airborne components. This is due to the presence of the precipitation effect.

Annual emissions from the HELCOM Contractig Parties in 2010 are shown below for all pollutants considered in the report.

Annual depositions of all considered pollutants in 2010 are shown in the Table below for 6 sub-basins of the Baltic Sea and for the entire Baltic Sea basin.

Oxidised nitrogen deposition in 2010 was higher than in 2009 in all sub-basins (2-26%) and in the entire Baltic Sea basin (20%). Reduced nitrogen deposition in 2010 was also higher (3-28%) than in 2009 in four sub-basins (BAP, GUR, GUF and GUB), and in the entire Baltic Sea basin (-2%). Reduced nitrogen deposition in 2010 was lower than in 2009 in two sub-basins: BES (-16%) and KAT (-12%).

Among the HELCOM Contracting Parties, the largest per cent of 2010 nitrogen emissions deposited to the Baltic Sea basin can be noticed for Denmark (14.9%) and the lowest for Russia (0.7%).

Germany, Poland, ship traffic on the Baltic Sea and Russia are the main emission sources contributing to oxidized nitrogen deposition into the Baltic Sea basin in 2010. There is not much difference compared to 2009 ranking. As in 2008 and in 2009, Germany, Poland and Denmark are top three sources contributing to reduced nitrogen deposition into the Baltic Sea basin in 2010. As in previous years, also in 2010 some distant sources like United Kingdom, France and ship traffic on the North Sea contribute significantly to nitrogen deposition into the Baltic Sea basin. Contribution from boundary and initial conditions (BIC) is slightly lower in 2010 than in 2009.

The results of the EMEP/MSC-W model are routinely compared with available measurements at EMEP and HELCOM stations. The comparison of calculated versus measured data indicates that the model predicts the observed air concentrations and depositions of nitrogen compounds within the accuracy of approximately 30%.

Levels of lead and cadmium deposition to the entire Baltic Sea has slightly decreased in 2010 comparing to 2009 by 2% and 1%, respectively. At the same time deposition of mercury and PCDD/Fs to the Baltic Sea from 2009 to 2010 has increased by 7% and 11%.

Anthropogenic emission sources of HELCOM countries contributed to the annual deposition over the Baltic Sea in 2010 about 14% for lead and mercury and about 40% for cadmium and PCDD/Fs, respectively. Essential contribution to total annual deposition belongs to other sources, in particular, natural emissions, re-suspension with dust, distant emissions and re-emission (from about 45% to 80%).

Most significant contribution to deposition of HMs and PCDD/Fs to the Baltic Sea in 2010 was made by Poland and Germany for lead and mercury, and Poland and Russia for Cd and PCDD/Fs.

Model results in comparison with available measurements for 2010 made around the Baltic Sea are within an accuracy of 40% for Pb, 70% for Cd and 10% for Hg.

Concerning weather conditions - most of Europe experienced more precipitation in 2010 than in 2009. It was also true for the Baltic Sea basin with much higher precipitation in 2010 than in 2009. The surface temperature of the Baltic Sea basin was higher in 2009 than in 2010.

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 sixth 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, joint summary report for HELCOM includes the measurements and results of modelling in the Baltic Sea region for oxidised nitrogen, reduced nitrogen, lead, cadmium, mercury and dioxins/furans for the year 2010. 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 page and later on the HELCOM WEB page. The report, as a draft, was presented and discussed at the Seventeenth MONAS Meeting in Gothenburg, Sweden, 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 final version of the report and in the final versions of the Indicator Fact Sheets, as well. All comments/corrections received from 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 Anna Benedictow, Per Helmer Skaali and Álvaro Valdebenito for their 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.

Last updated 7 January 2013