Finnish experience and emergency measures after the Chernobyl accident and fallout

Transcription

1 Finnish experience and emergency measures after the Chernobyl accident and fallout

2 Content The Chernobyl fallout in Finland, effects on Agricultural environment Natural and freshwater environment Baltic Sea environment Lessons learned from fallout situation Health effects on Finnish population Cooperation with stakesholders Emergency planning in Finland today

3 Chernobyl and Finland Most contamination to middle parts of Finland Maximum about 100 K Bq/m 2 Cs-137 ( +Cs-134 was about half of this) Minor amounts of Sr-90 and other nuclides In 1986 recommendations to farmers, food production, and guides for private garden production, fish, mushrooms etc.

4 Concentrations of Cs-137 in Finnish foodstuffs in 1986 (average deposition 40 kbq/m 2 ) Milk below 100 Bq/l (in summer) Beef Bq/kg (in autumn) Pork below 10 Bq/kg (in autumn) Lamb Bq/kg Chicken below 10 Bq/kg (in autumn) Eggs Bq/kg (in autumn) Wheat 2-14 Bq/kg Vegetables 0-40 Bq/kg Garden berries Bq/kg Bq/l 0 Cs-137 Monitoring of milk was started in Nuclear weapon tests had stronger impact on northern Finland (N), Chernobyl accident on southern Finland (SW). SW N

5 Remarks from the first years after the accident Radionuclide concentrations are at maximum in the first growing period in agricultural environment Accumulation of radionuclides depends on the phase of growing e.g. (in cereals: phase of grains) Stems and shoots accumulate more than grains Concentrations decrease rapidly during next years: Taking by roots is smaller Dilution and mixing with ploughing decrease concentrations Fixing of cesium by clay in the soil when mixed Fertilization decreases root taking Type of soil affect moving Turf type soil and low fertilized soil fix cesium least If the soil is not tilled: effective, ecological halflife of cesium-137 is years Concentrations of animal feed (and drinking water) has an effect on meat and milk concentrations (N.B. Stems of cereal!)

6 Deposition Cs MegaBq/m 2 Examples from the Finnish environment Beef (within a couple of months): Bq/kg Milk (in 6 days): Bq/l Cereal (next growing period) Seeds: Bq/kg Stems and shoots: Bq/kg Potatoes (next growing period) 3000 Bg/kg Surface water 90 Bq/l (1 week) 50 Bq/l (1 month) Tap water 50 Bq/l (1 week) 30 Bq/l (1 month) Freshwater fish (week-month) Bq/kg Pork 1000 Bq/kg

7 Some tested countermeasures for removing Cs from food chains and food Clean feeding period of animals before slaughtering Adding of Giese-salt (AFCF) or clay minerals to the feed if not clean Removing of growth in autumn from fields (before ploughing) Compost from first two years must be discarded, not used to soil enrichment Fertilization and liming of cultivated soil Ploughing Crop rotation (if possible) Treatment of meat and milk for removing Cs: Salting of meat/fish (Cs is removed to salt liquid) Preparing cheese from milk (Cs is removed to whey) N.B. Acceptability for farmers and food industry/consumers must be discussed!

8 Example: effect of clean feed After twelve weeks feeding with high concentration feed, clean feeding was started: Concentrations in the milk halved in four days Concentrations in meat halved in 21 days 137 Cs 1 0,8 0,6 0,4 maito Milk Meat liha 0, week viikko

9 Ascertain of the purity of foodstuffs Our main principles: Main focus on security of the purity of starting point of the product chain => end product is thus clean of contaminants e.g.: Soil (type, fertilization) -> vegetables Soil -> feed -> cow/domestic animals -> meat Soil -> feed -> cow -> milk Growing bed -> mushrooms, (vegetables) Purity of facilities -> food product This decreases/helps handling of waste Needs communication (guiding) with farmers, producers, people

10 Freshwater environment Unevenly distributed Cs-137 raised concentrations in surface waters by a factor of 1000 in some areas. Cesium decreased from water first quickly by sinking into the bottom sediments. During 10 years, 2% of Cs-137 was transported into the Baltic Sea by rivers. Effective ecological halflive of Cs-137 in the Finnish river waters is 4 8 years. Doses from drinking water, even if surface water was used, have been low, less than msv per year. In the course of time, characteristics of the lakes and their catchments have affected greatly the distribution of Cs-137 in lakes. Ecological halflives change in the course of time. Bq/m T 1/2 = 50d T 1/2 = 1y Päijänne, Asikkalanselkä T 1/2 = 5y

11 Bq/kg f.w. Freshwater fish Non-predatory fishes contaminated quickest after the deposition (during a month few months). Maximum concentrations in predatory fishes were detected between from a year to three years after the deposition. Concentrations in fishes varied substantially both lake-specifically and regionally. In the areas of the highest Chernobyl Cs-137 deposition in Finland, Cs-137 in freshwater fishes varied from a few to several thousands of Bq/kg fresh weight still in the 2000s Nonpredatory Predatory Intermediate kbq/m2 Cs-137 in freshwater fish in areas with various depositions in 2000s

12 Mushrooms After the Chernobyl accident (1986) the maximum values in mushrooms were detected in Maximum values were several thousands of Bq/kg. Cs-137 amounts have decreased slowly, in 2008 they were about 40% of maximum values. Concentrations differ largely according to species in the same area. Concentrations of some commercial mushrooms in Finland can still exceed the maximum permitted level, 600 Bq/kg (on the market). Even if concentrations are high, mushrooms can nevertheless be consumed: radiation doses from the relatively small amounts of them consumed in a year are minor. The annual radiation dose for an average Finnish consumer varies between millisv, and for heavier consumers between milliSv. Concentrations can be reduced through a certain treatment more than 90% (washing and boiling with water, salting).

13 Forests and game In forests, deposition first distributes on trees, underlying plants and soil. When leaves and needles are falling, the distribution changes. The soil and nutrient cycle in forest differ from that of agricultural soil cesium does not move into the deeper layers of soil. Cesium stays in the surface layers of soil and is thus available for plants (berries) and mushrooms for a long time (acc. only to the physical halflife.) Basic fertilization (P-K fert.) decreases the transfer of cesium to plants and trees. Concentrations in various parts of a tree differs with the time: barks, branches and and needles accumulate cesium first, the maximum is found in phloem. Timber is the cleanest part of a tree, about 100 Bq/kg at maximum (2010) Moose and other game eat forest plants and mushrooms meat concentrations varied according to the season (maximum was about 1000 Bq/kg) Chernobyl fallout was minor in Lapland concentrations in reindeer meat decreased rapidly from more than 1000 Bq/kg to about 200 Bq/kg. N.B! High concentrations in bark and phloem, if logs are used as growing beds

14 Bq/m 3 Baltic Sea environment The Baltic Sea area received a remarkable Cs-137 fallout from the Chernobyl accident, making it one of the most contaminated seas. The maximum measured concentration was 3 Bq/l (3000 Bq/m3). Effective ecological halflife for Cs-137 in the Baltic Sea water is about ten years. However, Cs-137 concentrations in Baltic Sea fishes have been considerably low, some ten Bq/kg at maximum. Accumulation of radionuclides in sea water environment from water to fish is much lower than in freshwater environment. Example: if the concentration in water is 1Bq/l => in the Baltic Sea fish: 150 Bq/kg and 50 Bq/kg in mussels. In algae, the concentrations are from ten to hundreds times fold compared to those in water year 1996 Baltic Proper (BY 15, except 1989:BY 2) Bothnian Bay (C VI) Bothnian Sea (EB 1) Gulf of Finland (LL 3a) Cs-137 concentrations in sea water in different parts of the Baltic Sea

15 msv Average doses from Chernobyl fallout to the Finns Average doses to the Finns from the Chernobyl fallout Inte Ext Average radiation doses (msv) for Finnish population Indoor radon External natural radiation Cosmic radiation Internal natural radiation X-ray (medical) It is important to tell to people how much is much! 0.45 In certain areas of Finland this can be more than 10 msv/y Radioisotopes (medical) Chernobyl (internal and external)

16 Health effects of the Chernobyl fallout in Finland Three epidemiological research projects, continued until now, were completed dealing with the health effects of the Chernobyl fallout in Finland Risk of childhood leukemia: No increased risk of childhood leukemia in Finland Child and adolescent thyroid cancer: No increased risk of child and adolescent thyroid cancer Total cancer in Finland: No increased risk of total cancer following the Chernobyl accident

17 Lessons learned More knowledge of decontamination was needed: Several national and international projects with testing, e.g. FARMING-project, EURANOS handbooks, Nordic Handbooks etc. Contamination stays in natural environment Monitoring and guiding of people still continues A new research area: urban environment Distribution of contamination Clean-up techniques (EURANOS, Nordic Urban handbook...) Waste problem is remarkable Need of good planning of monitoring, classification and storage N.B! Ashes from burned waste, wood, turf etc. Sewage, rainwater systems etc. People also want to clean their own living environment themselves A big need of sharing knowledge and guidance also to general public All stakeholders want to do their part, require knowledge, discussion and guidance The continuous monitoring and observations of time trends of the radioactive substances form the basis for knowing and understanding the state of radioactivity in the environment.

18 Cooperation with stakeholders Principle: sharing responsibility across society State and municipal authorities as well as private sector cooperate and coordinate their respective measures in all situations. Non-governmental organisations, for their part, also support cooperation. Examples of good practices: The food supply pool: and the Finnish Food and Drink Industries Federation often take part in full scale nuclear emergency exercises giving valuable feedback to authorities. STUK has asked for - and received - feedback and comments when preparing guidelines of protective measures for food industry in case of a nuclear or radiological emergency. Communication arrangements for emergencies have been set. In planning the waste handling : All stakeholders dealing with waste disposal participated in seminars for preparing the report. E.g. the following partners were represented: municipalities, private waste management organisations, food production factories and authorities of environmental protection.

19 Emergency planning and arrangements in Finland today Plans and procedures Detailed national guides for General radiation protection Early phase Intermediate phase Protective actions Criteria for different countermeasures Criteria for different waste Protection of workers (Monitoring strategy) National discussion and planning for waste management National discussion and clarifying of responsibilities of different authorities Involving stakeholders largely on development (and exercises) Communication plan International cooperation Training and exercises Emergency facilities, tools and software

20 A lot can be done in Fukushima area Some areas are heavily contaminated, but there are remedial measures that can be taken. Most of the contamination is mostly still on the surfaces: better to focus on surface decontamination: Washing and cleaning of urban areas (also buildings inside) Removing certain parts of vegetation and surface layers of soil in the vicinity of living areas Decontamination of the primary production of foodstuffs Plan for waste collecting and storage People s own initiative to help (everybody wants a clean living environment) Monitoring focused on right things e.g. nearest living area, primary production of foodstuffs Sharing of knowledge = sharing of trust Sharing of guides to every level not forgetting general public ALL OUR EXPERIENCE AND KNOWLEDGE IS AVAILABLE FOR YOU

21 All of us wish all the best we appreciate and promote your efforts to have a good and healthy living environment