Water quality of lakes, rivers and sea areas in Finland in 2000–2003 Finland is known as a land of numerous lakes and The Baltic Sea is shallow with a mean depth of only Since the beginning of the 1970s, three national water clean waters. There are about 56 000 lakes with a 55 metres. The fact that the Baltic Sea forms a mostly protection programmes have been prepared, and the surface area of over one hectare and about 2600 lakes closed, shallow and cold brackish basin means that Government has adopted the two most recent ones. larger than one square kilometre. coastal waters are also highly vulnerable to pollution. In these programmes quantitative targets for the Harmful substances degrade slowly under the cold most important pollution sources were defi ned. The Because of the relatively cold climate and prevalent conditions and the winter ice cover prevents oxygen third national water protection programme approved pre-Cambrian bedrock, the rate of weathering is being transferred from the air to the surface water. by the Government in 1998 sets targets for the year slow and, therefore, the concentrations of inorganic 2005. The long-term goal is that the state of the Baltic substances in Finnish surface waters are low. By Finland has achieved good results in water protection Sea and of inland surface waters is not degraded any contrast, the concentrations of dissolved organic by setting quantitative national water protection further by human activities. The main aim of this substances, for example, humic acids, can be high targets with specifi c time frames. The United Nations programme is to reduce the eutrophication of the locally, since bogs cover about 30% of the area of the World Water Assessment Programme examined water waters. country. The waters of Finnish lakes and rivers are quality indicator values in 122 countries. Finland mainly soft and often humic. The shallowness of lakes was the highest ranked country in this assessment In April 2002, the Finnish Government adopted (average depth about 7 metres) and relatively low (the World Water Development Report in 2003). Finland’s Programme for the Protection of the Baltic discharges of rivers, together with the long period of According to the water poverty index devised by the Sea. Steps will be taken to combat eutrophication, ice cover, make inland waters sensitive to pollution. World Water Council and the British Centre for decrease the risks caused by hazardous substances, Generally speaking, the water quality of Finnish Ecology and Hydrology, Finland was also ranked reduce the risks of maritime traffi c, protect inland waters improves from south to north and number one in the world, among 147 countries biodiversity, and increase environmental awareness from west to east, being poorest in coastal areas in the included in the comparison. The criteria of this and research. south, southwest and west. comparison included resources, access, capacity, use and the environment. However, there is In many places, lakes and rivers form lake chains. still a lot of work to be done on water Finland’s rivers have a combined length of more than protection, for example, reducing 21 000 kilometres, but mostly they are very eutrophication in lakes and the Baltic short individually. Sea. Excellent Tenojoki The Finnish coast is heavily embayed and Inari fringed with 73 000 islands and islets. Good Satisfactory 4.4% 0.3% Porttipahta Reservoir Lokka Reservoir Passable 15.1% 38.2% Poor Lakes Muonionjoki Ounasjoki 42.0% 2.1% 7.6% Kemijärvi 31.0% Rovaniemi 35.1% Rivers Tornionjoki Yli-Kitka ijoki Kem 24.2% 0.03% 1.0% Iijoki 25.6% Kiantajärvi 40.1% Oulu www.environment.fi/waterquality Sea Oulujärvi 33.2% Pyhäjoki Kajaani Kokkola Vaasa Lappajärvi Pielinen Kyr önjoki Keitele Kuopio Kallavesi Jyväskylä Näsijärvi Pori Mikkeli Tampere Kokemäenjoki Saimaa Päijänne Lappeenranta Pyhäjärvi Hämeenlinna Kouvola Kymijoki Turku Kotka Maarianhamina Helsinki Finnish Environment Institute (SYKE) n Regional Environment Centres g * The sulphate (SO 2-) in acid sulphate soils was formed during 7500– The general usability classifi cation Water quality affected by diffuse loading Poor: Wastewaters, diffuse loading or other changing 4 activity extensively pollutes the watercourse. Algal blooms 2500 B.P., in the warm Littorina period, when the soils were covered with sea water. Littorina Sea clay is found in coastal areas of Finland. The general usability classifi cation of water bodies gives an In the vicinity of towns and industrial plants, water quality occur frequently and are often abundant, restricting water idea about the average suitability of the water bodies for had improved considerably already at the beginning of the use for a long period. Oxygen concentrations are clearly water supply, fi shing and recreation in Finland. The quality 1990s, because of long-term measures for water protection. affected by eutrophication. Concentrations of harmful class is determined based on the natural quality of the water These measures were further improved during the 1990s. substances in water, sediment or biota can be at levels that and human impacts. The water bodies have been classifi ed However, a similar improvement in the state of water bodies Comparison of the two latest work has already started in Finland. In the future, the cause a clear risk to the use of water or biota. In catchments into fi ve classes: excellent, good, satisfactory, passable and has not been observed in areas with heavy diffuse loads. classifi cations classifi cation will be based more on the ecological state with Littorina Sea* clay deposits, the pH of water can be poor. of water bodies. This will be done by comparing such very low for long periods and die-offs of fi sh caused by the Water quality is also affected by weather conditions and 2000–2003 1994–1997 factors as fi sh fauna, benthic fauna and macrophytes with acidic conditions occur repeatedly. Poorly suited to any Water quality mostly good in lakes variations in runoff. During the years 2000–2003 there were conditions in which the human impact is negligible. mode of use. periods where the water quality clearly deteriorated. In 2002 2 2 and the open sea Lakes km % km % most of the country suffered from the worst drought in Excellent 10,110 38.2 9,730 37.8 Criteria for the general water quality The classifi cation was based on data from the period 2000– several decades, which caused water levels to drop in many Good 11,130 42.0 10,880 42.3 classifi cation in Finland Criteria for the general water quality classifi cation 2003 and covered 82% of the total area of lakes with size water bodies. During the winter of 2002–2003, extremely Satisfactory 4,010 15.1 3,990 15.5 greater than one square kilometre, 16% of the total length poor oxygen conditions were observed in about 450 small Passable 1,160 4.4 1,070 4.1 g Excellent: The watercourse is in a natural state, usually Variable Unit I II III IV V of rivers with width more than two metres, and the sea area and shallow lakes, especially in southern and western Poor 79 0.3 67 0.3 100 oligotrophic, clear or with some humus. Water use is inside the Finnish territorial waters. Finland, and mass die-offs of fi sh occurred in many of these Total 26,490 100 25,737 Excellent Good Satisfactory Passable Poor not restricted by any special occurrence of algae. Highly -1 lakes. The main reasons for the severe oxygen problems were Chlorophyll-a (lakes, rivers) µg l < 4 < 10 < 20 20–50 > 50 Rivers km % km % suitable for all modes of use. -1 an early ice cover and the low water levels. Low water levels Chlorophyll-a (sea) µg l < 2 2–4 4–12 12–30 > 30 The quality of water was excellent or good in 80% of the Excellent 1,600 7.6 1,490 7.7 -1 classifi ed lake area and in 73% of the sea area. In general, also contributed to the degradation of rivers, especially in Good 7,430 35.1 6,030 31.2 g Good: The watercourse is in a near-natural state, Total phosphorus (lakes, rivers) µg l < 12 < 30 < 50 50–100 > 100 southwestern Finland. -1 the water quality in rivers was worse than in lakes, because Satisfactory 5,130 24.2 5,860 30.4 slightly eutrophic or clearly humic. Locally restricted algal Total phosphorus (sea) µg l < 12 12–20 20–40 40–80 > 80 human activities, such as agriculture and development, are Passable 6,570 31.0 5,640 29.2 blooms can occur occasionally. Water is still suitable for Transparency m > 2.5 1–2.5 < 1 - - concentrated along rivers. Moreover, many rivers are Regular data collection Poor 450 2.1 290 1.5 most modes of use. Total 21,180 100 19,310 100 Turbidity FTU < 1.5 > 1.5 - - - sensitive to the effects of nutrient loading because of their -1 1 low fl ow rates. Some 43% of rivers are classifi ed as excellent In Finland water quality has been classifi ed since the 1970s. Colour mg l Pt < 50 50–100 (< 200) < 150 > 150 - Using the same criteria, the environmental authorities 2 2 g Satisfactory: The watercourse is slightly affected by or good quality. These rivers are mostly located in northern Sea area km % km % Oxygen in surface water % 80–110 80–110 70–120 40–150 serious problems have carried out the classifi cation procedure four times for Excellent 21,090 40.1 22,370 42.5 wastewaters, diffuse loading or other changing activity, or Finland. Oxygen depletion in hypolimnion no no occasionally frequently common inland waters and twice for sea areas.