3 POLLUTION SOURCES
3.2 Diffuse land-based pollution
Information on the diffuse waterborne inputs of hazardous substances from land is somewhat scat-tered. In this section, information is provided on riverine inputs of persistent organic pollutants and heavy metals, on pesticides, and on losses from various types of goods, articles and materials.
3.2.1 Riverine inputs of POPs and heavy metals
Rivers are one of the main pathways of contami-nants from diffuse sources as well as inland point sources to the Baltic Sea. Heavy metals in the Baltic Sea enter largely via riverine inputs (Fig. 3.3). In 2006, about 85% of cadmium, 75% of mercury and 50% of lead inputs entered the Baltic Sea via rivers or as direct waterborne discharges. The remainder arrived via atmospheric deposition. Due to incomplete data sets, it is diffi cult to assess temporal trends of riverborne heavy metal inputs.
However, it is quite clear that lead inputs from Poland and Sweden have decreased signifi cantly,
cadmium inputs from Germany and Lithuania 65
The largest riverine inputs of PCBs to the Gulf of Finland enter from the Okhta River, Chernaya River and Sestroretsk in the Russian territory (Roose &
Roots 2005). The annual Estonian riverine input of PCBs was approximately 332 kg in 2003 (Roose &
Roots 2005).
The River Vistula has the second largest catchment, covering 12% of the Baltic Sea catchment area. It carries large amounts of pesticides, alkylphenols, metals, detergents, PAH compounds and aromatic amines, originating from agriculture, wastewater treatment plants and several industrial complexes in the area (Galassi et al. 2008). The contaminants from the Vistula River are deposited as sediments in the Gdansk Deep (Sapota 2006).
The River Oder is the only large river fl owing into the Bornholm Basin, the deepest part of which is a sink for organic pollutants from the Oder and the Szczecin lagoon (Sapota 2006). The catch-ment area of the River Oder is the third largest in the Baltic Sea (8%, Table 3.2). The fourth largest catchment, covering 6% of the Baltic Sea catch-ment area, is for the River Nemunas, which is the major river fl owing into the Eastern Gotland Basin. A signifi cant part of its waters originate from Belarus. The River Daugava is the main source of pollution inputs to the Gulf of Riga and has the fi fth largest catchment area in the Baltic Sea (Nordic Environmental Research Programme 1999).
The Arkona Basin, Mecklenburg Bight, Kiel Bight, Little Belt, Great Belt and the Sound have very small catchment areas and no large rivers.
However, the Kattegat, receives drainage from three large river catchments, the Göta, Lagan and Gudenå, as well as from the Danish fjords Limfjord, Mariager fjord, Roskilde fjord, Randers fjord and Odense fjord.
3.2.2 Pesticides in the catchment area
Pesticides typically originate from land-based sources. In the marine environment, they are mainly found near river mouths and urban areas (Galassi et al. 2008). A Russian study on the riv-erine discharges of pesticides concluded that the Russian Federation has particularly discharged DDT and its derivative DDE to the Baltic Sea (Zhulidov et al. 2000). On the other hand, concentrations of pesticides in Estonian river water and sediment Table 3.2 The ten largest river catchment areas around the Baltic Sea.
River Catchment area km2 (%) Baltic Sea sub-basin
1. Neva 285 063 (17%) Gulf of Finland
2. Vistula 192 196 (12%) Gulf of Gdansk
3. Oder 130 708 (8% Bornholm Basin
4. Nemunas 95 380 (6%) Eastern Gotland Basin
5. Daugava 90 073 (5%) Gulf of Riga
6. Velikaya 56 348 (3%) Gulf of Finland
7. Göta 54 000 (3%) Kattegat
8. Kemijoki 51 921 (3%) Bothnian Bay
9. Tornionjoki 40 345 (2%) Bothnian Bay 10. Kymijoki 37 352 (2%) Gulf of Finland
0 20 40 60 80 100 120 140
NEVA VISTULA DAUGAVA KOKEMÄENJOKI DALÄLVEN KYRÖNJOKI GÖTA ÄLV KARVIANJOKI LAPUANJOKI KYMIJOKI SLUPIA UME ÄLV LULE ÄLV LEBA PITE ÄLV LUPAWA KEMIJOKI PEENE ÖRE ÄLV PASLEKA NARVA
Cd and Pb loads (tonnes)
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Hg load (tonnes)
Cadmium Lead Mercury
Figure 3.3 Riverine inputs (tonnes) of cadmium (Cd), lead (Pb) and mercury (Hg) to the Baltic Sea in 2006 (unpublished data from HELCOM PLC 5). Note that data on the load of mercury from River Vistula is lacking.
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are below target levels (Roose & Roots 2005) because the use of pesticides decreased sharply in the early 1990s. Estimates of the annual Estonian riverine inputs of DDT and HCHs were 2.8 kg and 47.5 kg, respectively, in 2003. Poland covers 20%
of the catchment area but has almost 50% of the agricultural land in the Baltic Sea catchment area.
Pesticides such as DDT and its degradation prod-ucts have been found in large quantities in the Gulf of Gdansk, which may indicate a quite recent origin of pollution in the area (Galassi et al. 2008).
DDT was banned in 1996 in Poland. Belarus is the only country in the Baltic Sea catchment area in which many pesticides have not been banned, but it is not known whether they are still used or their amounts. Because Belarus covers 5% of the whole catchment area, its impact on the riverine input of pesticides to the eastern and southeastern Baltic Sea may be signifi cant.
3.2.3 Losses from various types of goods, articles and materials
An area that defi nitely needs more attention is the diffuse losses from various goods, articles and materials. There are presently several research programmes being conducted in the Baltic Sea region, but the quantities of such losses are still a matter of great uncertainty. It has been estimated that leakage from products is the main pathway for brominated substances (PBDEs and HBCDD), fl uorinated substances and nonylphenols (HELCOM 2009c). PBDEs are used as fl ame retardants in furniture, which have a half-life of use of 10 years.
During that time, about 0.39–0.54% of PBDEs vol-atilize (EU-RAR 2000). In many countries, HBCDD is used as a fl ame retardant primarily to produce polystyrene (for use as building insulation), but it is also used in electrical products and textiles. Fluori-nated compounds are used in the impregnation of textiles, leather, paper and cardboards, but also in cleaning products. Nonylphenols have been used extensively in the plating industry and cleaning products, and they also leak to the environment from waste sites (HELCOM 2009c).
The brominated fl ame retardants PBDEs can be used as an example to illustrate a product-based emission source to the marine environment. Penta-BDE and octa-Penta-BDE have probably entered the Baltic Sea area as additives to various forms of plastic polymers and textiles. There were previously also
0.00
Figure 3.4 Total waterborne inputs of A) lead, B) mercury and C) cadmium to the Baltic Sea sub-basins in 2006 (Knuuttila 2009). The fl ow (m3 s−1) indicates the average annual riverine infl ow entering each sub-basin. The mercury load from River Vistula has been removed due to unreliable monitoring data.
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initiative VECAP14 has also implemented a volun-tary programme with major emissions reductions on the agenda. HBCDD is, however, still frequently used as an additive to insulation materials in Eastern Europe, which might explain the continued upward trend for HBCDD. Based on the experience of the losses of hazardous substances from house-hold products, it is important to take action not only on emissions from point sources, but also on the use of substances within articles.