Latest Pollution Load Data from All Baltic Sea Countries Released

The Fifth Baltic Sea Pollution Load Compilation (PLC-5) on total waterborne loads of nutrients and some hazardous substances to the Baltic Sea was released on the HELCOM website in November 2011. The long-awaited report compiles data collected and assessed by all the nine HELCOM states around the Baltic Sea.

Since 1994, the HELCOM member states have reported their pollution loads to the Baltic Sea on an annual basis. Although the report covers data from 1994 to 2008, the main assessment of contributions of nutrient loads from different sources is based on measurements taken during 2006.

“The release of the PLC-5 report is great news,” says the Project Manager Mr. Seppo Knuuttila. “It is the result of seven years of dedicated work by pollution load experts. In spite of data gaps and difficulties in comparing the results from different countries, we have succeeded in compiling and assessing the latest available data on pollution loads to the Baltic Sea.”

“Load compilations are crucial for the core work of HELCOM and the protection of the Baltic Sea. They provide the basis for joint assessment whether HELCOM countries are achieving the provisional nutrient reduction targets that were agreed upon in the HELCOM Baltic Sea Action Plan in 2007, and forreviewing these targets,” says Mikhail Durkin, HELCOM Professional Secretary. 

Based on the PLC-5 data, it is estimated that waterborne inputs of nutrients to the Baltic Sea amounted to 638,000 tonnes of nitrogen and 28,400 tonnes of phosphorus in 2006. About 5 per cent of the nitrogen load originated from point sources discharging directly into the Baltic Sea, while the rest was transported via rivers. For phosphorus the contribution from these sources was higher, about 8 per cent.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

According to the report, agriculture continues to be the main diffuse source of nitrogen and phosphorus inputs into the Baltic Sea. Nutrient losses from anthropogenic diffuse sources accounted for about 45 per cent of the total reported phosphorus and nitrogen loads into the Baltic Sea and of this, the share emanating from agriculture was about 70 - 90 per cent for nitrogen and 60 - 80 per cent for phosphorus.

Riverine loads are much higher than direct loads from point and diffuse sources, with the large catchment areas of major rivers, such as the Neva, Vistula, Oder, Nemunas and Daugava being major sources of nutrient inputs to the Baltic Sea. The area-specific loads of nutrients (measured as kilogram nutrient per square kilometre) are typically greatest in sub-regions with intensive agricultural activity, many industries and high population density.

The work on the PLC-5 began already in 2004 when the guidelines for monitoring and reporting the pollution loads for 2006 were agreed upon. Since then the HELCOM countries have been collecting water samples, analysing and assessing the data and reporting it for inclusion in the HELCOM PLC database. The completion of the report has been delayed numerous times due to challenges in compiling and verifying data.

From 1994 to 2008, the overall reduction in phosphorus inputs to the Baltic Sea was almost 20 per cent and nitrogen loads decreased by about 13 per cent. The reductions in nutrient discharges have mostly

taken place in the municipal wastewater treatment and industrial sectors in HELCOM countries. Over the long term, these sectors have been most successful in reducing their discharges into the Baltic Sea. With still a clear need to further reduce nutrient inputs to the Baltic Sea, however, the PLC-5 report presents an approach for estimating the nutrient reduction potentials in different sectors.

For the first time the Compilation report presents flow-normalization and a statistical trend analysis of nutrient load data. This is an important step forward because it is challenging to determine the effectiveness of pollution prevention measures over time, in particular because riverine pollution loads are affected by climatic conditions. Water flow in rivers varies over time, mainly as a result of variations in rainfall and temperature. Smoothing out the effect of such variations in water flow, through flow-normalization, is necessary for determining long term trends and for assessing whether the agreed targets of the Baltic Sea Action Plan are achieved.

 

An Executive Summary of the PLC-5, including the most recent data on waterborne loads, but also airborne inputs, to the Baltic Sea, will be released during 2012.