Baltic Marine Environment
Protection Commission


Baltic Marine Environment
Protection Commission


​Sixth Baltic Sea Pollution Load Compilation 


The project is an implementation of HELCOM Recommendation 26/2 to, every sixth year carry out a pollution load assessment (PLC) including a quantification of waterborne point, diffuse and natural sources. The timing of the PLC-6 report will also provide those Contracting Parties that are EU member states with input for 2018 reporting requirements under the EU Marine Strategy Framework Directive (MSFD). Furthermore, the results of the PLC-6 project will provide valuable information for assessing progress in reaching the HELCOM Baltic Sea Action Plan nutrient reduction targets, including expected nutrient reductions as a result of implementation of the EU Water Framework Directive (WFD) river basin management plans by the HELCOM EU countries and to overall evaluate effectiveness of nutrient reduction measures taken within the Baltic Sea catchment area.


The overall task of the project is to prepare a comprehensive assessment of the water- and airborne inputs and their sources to the Baltic Sea during the period 1994-2014 with more detailed assessment for 2014 by:

  • Updating the 5th Pollution Load Compilation (PLC-5) and the updated PLC report submitted to the 2013 HELCOM Ministerial Meeting (PLC-5.5), including information on nutrient inputs via air and water, as well as their sources.

  • Further updating the PLC Guidelines and extending them with new standardized methods, standard values, statistical assessment for improving data quality and quantifying uncertainty on national datasets to ensure more complete,  consistent and comparable data between Contracting Parties, and complying with new requirements for follow-up of the fulfilment of nutrient input reductions targets agreed upon within HELCOM (e.g. 2007 Baltic Sea Action Plan, BSAP and possible revised reduction requirements after HELCOM Ministerial Meeting in 2013).

The Sixth Pollution Load Compilation (PLC-6) project will be carried out in six consecutive stages

  1. Development of standardized methodology to calculate uncertainties on national datasets including methodology for filling in data gaps and missing data and development of standardized methodology for evaluating countries progress in fulfilling BSAP nutrient reduction targets
  2. Quality Assurance standardisation activities and carrying out intercalibration/ intercomparison activities
  3. Updating and extending of the PLC-water Guidelines
  4. National monitoring in 2014 (Poland and one federal state in Germany in 2012)
  5. Data collection, submission, national quality assurance and compilation and corresponding activities by data manager, taking into account the modernization of PLC database
  6. Data assessment, data products including air blame matrixes, preparation and publication of PLC-6 Report and an executive PLC6 summary

Expected results

The objectives of the sixth periodic pollution load compilation on pollution of the Baltic Sea from land-based sources are to:

  1. Compile information on the waterborne inputs of important pollutants (primarily nitrogen and phosphorus) entering the Baltic Sea during 1994 to 2014 and from different sources in the Baltic Sea catchment area on the basis of harmonised monitoring methods
  2. Compile information on airborne input of nitrogen, phosphorus and selected hazardous substances to the Baltic Sea sub-basins from different countries and sources by using information delivered by EMEP
  3. Assess long-term changes in the pollution load to the Baltic Sea by normalizing data and making trend analysis with standardized methodologies
  4. Determine the priority order of different sources of pollutants for the pollution of the Baltic Sea
  5. Overall, assess the effect of measures taken to reduce the pollution load in the Baltic Sea catchment area
  6. Assess the development of nutrient waterborne and airborne loads to evaluate progresses in fulfilling nutrient reduction targets of the Baltic Sea Action Plan from different countries to the different main Baltic Sea sub-basins
  7. Provide information for assessment of long-term changes and the state of the marine environment in the open sea and the coastal zones
  8. Develop standardized methodology to calculate statistical uncertainty on national datasets, methodology for filling in gaps and missing data and development of standardized methodology for evaluating countries progress in fulfilling BSAP nutrient reduction targets
  9. Develop revised and extended PLC guidelines.

A popular report, summarizing the air and waterborne loads of nutrient inputs to the Baltic Sea shall, be produced after the finalization of the PLC-6 report.​

Related documents

For more information, please contact:

Lars Svendsen​
Project Manager

Chair of HELCOM Expert Group on follow-up of national progress towards reaching BSAP nutrient reduction targets (HELCOM LOAD)
Danish Centre for Environment and Energy (NERI)
University of Aarhus
Vejlsoevej 25
DK-8600 Silkeborg, Denmark
Tel: +45 4587158795