Experience in application and

efficiency assesment of protective measures used after the Chernobyl

accident

academician, prof. Prister B,

bprister@mail.ru

2

2

ext. ext.

int . int.

* * roughness,deepening,energy...

* * TF-soil,animal,human,consumption...

D kBq m K

D kBq m K

A basic parameter for a decision-making about conducting counter-measures

is a dose of irradiation of population.

The doses of external and internal irradiation are proportional the density

of radio-active contamination of territory and its ecological properties:

Therefore, the priorities are carrying out monitoring of soil contamination and prediction intake of radionuclides in plants

Values of agrochemical characteristics of the main soil types Ukrainian Polesie and Forest-Steppe were vary in a wide range

Type of soil pH Organic matter, %

The sum of absorbed cations,

mg/100 g of soil

Peat - bog 3.8 – 6.6 - 2.3 – 19

Soddy - podzolic 4.4 - 6.5 0.40 – 1.8 6.0 - 18

Grey forest 5.3 – 6.6 0.92 – 1.9 8.4 - 17

Chernozem 5.4 - 7.5 1.5 - 3.9 10 - 33

Each soil type consisted of 3 to 15 soil differs

4

The spatial distribution of internal radiation dose is determined more by ecological factors than by Cs-137 fallout density – that is why in settlements located at 300 km from ChNPP the dose is

higher than in settlements around epicenter of the accident.

[Likhtarev,2006]

5

The spatial distribution of internal dose the population of Rivne region due to the consumption of milk (cow pasture, a 137Cs contamination of the Ci/km2),

calculated using the model

• In the first days after the Chernobyl accident were identified spots with significantly higher density of contamination of Cs-137. There is a need in the shortest possible time to identify critical areas in order to clarify their radiation environment and the countermeasures.

• In June 1986 we have developed a technique and with agronomic and agrochemical services Gosagroprom USSR and sanitary-epidemiological service of the monitored soil farmland. Sampling was carried out by taking the average representative sample for each of the 445 administrative districts of Ukraine. Individual samples were collected on five fields of each of the 25 - 28 farms area in each district.

• The samples were combined and mixed in the back of dump truck and an aliquot was used for measurements. Gamma-spectrometric analysis of Cs-137 and Sr-90 determination of radiochemical were assigned to 11 research teams and regional zonal agrochemical laboratories of Ukraine under centralized metrological support.

• For 10 days the average levels of pollution map of the territory of the 445 regions of Ukraine long-lived radionuclides, which revealed all the spots with elevated density of fallout.

• We proposed to provide such monitoring in Fukusima region.

Monitoring of contaminated territories (Soils)

8

In order to predict contamination of crop production is very importance that for Cs-137 confirmed a linear relationship between specific activity in plants (kBg · kg-1) and soil contamination density (kBq * m-2), proved for Sr-90 in the track of the Kyshtym

accident

The value of  TF of radionuclides does not depend on the density of soil contamination for all types of crops on all soil types

9

Dynamic of transfer factors TF of radionuclide in plant from soil

t

T

0.693expat

T

0.693expaTF(0)TF(t) s

e

s0q

e

q0 )t

T

693.0exp()0(TF)t(TF

e

Cs-137, Soddy-podzol soil:--- hay of natural grass; --- hay of sown grass;--- grain of wheat.

Cs-137, Hay of sown grass on soil:--- peat-bog;--- soddy-podzol;--- chernozem.

Sr-90 Bulb of potatoe on soil:--- soddy-podzol;--- gray-forest;--- chernozem.

10

Analysis for dynamics of radionuclides TF from soil to plants showed that the values of Cs-137 TF decreased with time after deposition. In the first 3 - 5 years the decrease is rapid, and in the following - is slow.

The value of Sr-90 TF decreases monotonically during the post-accident period.

Analysis showed that the half-decrease periods of TF are similar for different plants species on the soil of the same type. This means that the biological characteristics of the plants did not affect the processes of transformation of radionuclides forms in the soil.

Comparison of these parameters for different soil types with the characteristic of time of sorption equilibrium establishment in the soil allowed us to describe the scheme of radionuclides forms transformation.

11

Average for groups of crops values of transfer factors TF(0) 137Cs extrapolated to the time of fallout,

(kg-1м2 )·10-3 ( ± 25%)

Crops Peaty-bog Soddy-podzolic

Grey-forest

Cherno zem

Hay of natural grasses 223 29 10 -

Hay of sown grasses 95 5.8 4.9 3.3 Green fodder clover, alfalfa, corn

39 2.5 1.9 1.6

Vegetable cabbage, tomatoes, cucumber

- 2.9 2.0 1.2

Roots, tubers bulb onion, beet, potato

10 1.6 0.63 0.60

Cereal grain winter wheat, barley, ray

7.3 0.90 0.66 0.36

10 – 30 times

15-30 times

12

The range of average values TF Cs-137 in different types of grassland herbage in 1987 (n=240, σ ≤ ± 50%)

Type of soil Type grassland Range for TF, (Bq/kg)/(kBq/m2)

Soddy-podzolic loamy terrestrial normal 1.0 - 4.1

floodplain wet 2.1 - 6.0

Meadow sandy terrestrial normal

terrestrial normal 2.1 - 5.0

floodplain wet 8.8 - 12.8

Soddy-podzolic sandy

terrestrial absolute 3.5 - 8.0

terrestrial normal 5.2 - 13.1

Terrestrial excess humidified 16 - 32

floodplain wet 29 - 49

Peat-bog

Terrestrial drained 35 - 55

Floodplain wet 67 - 92

Lowland wetlands 165 - 221

Critical product on contaminated territory is the milk.

Forage grasses are critical fodder, especially in the growing organic wetlands and sandy acidic soils.

Decontamination (dezactivation)

Iodine blocking

Evacuation

Limit on the pastering of animals

Limits on a consumption of the fresh plant-grower and stock-raising products

Agromeliorativnye measures

Veterinary and zootechnics counter-measures

Processing of products of plant-grower and stock-raising

Dynamics of conducting of counter-measures after an accident

Day Week Month Year 10 years 20 years

The three basic principles the concept of agriculture in the affected areas

• To avoid individual dose exceeding the content of Cs-137 in the product must not exceed permissible levels.

• It is implemented by carrying out countermeasures (budget).

• If action is not advisable to conduct activities on the territory ceases.

• 2. Minimization of the collective dose is achieved by reducing the flows of Cs-137 into the body through measures that are selected to conduct optimization procedures and are implemented if a significant effect on the radiation situation.

• 3. Countermeasures - always intervention. When choosing them consider not only radiological, but also social, medical and other factors.

15

Change in time of the area of agricultural land, where lime (A) and fertilizers be applied (B)

as countermeasures in the former Soviet Union contaminated by the Chernobyl accident, ha.

A

0

500

1000

1500

2000

2500

3000

1986-1990 1991-1995 1996-2000 2001-2005

Years

Tre

ate

d a

rea

, th

. he

cta

res

Russia

Ukraine

Belarus

B

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

1986-1990 1991-1995 1996-2000 2001-2005

Years

Tre

ate

d a

rea

, th

. he

cta

res

Russia

Ukraine

Belarus

16

The dynamic of the applying of the fundamental improvement of the grassland contaminated after the

Chernobyl accident, ha.

0

100

200

300

400

500

600

1986-1990 1991-1995 1996-2000 2000-2005

Years

Tre

ate

d a

rea

, th

. he

cta

res

Russia

Ukraine

Belarus

Сельскохозяйственные контрмеры экономически оправданы – они существенно повышают продуктивность почвы и урожай.

Countermeasures

137Cs 90Sr

Soil

mineral organic mineral organic

Liming, 4-6 t/hа 1.5-3.0 1.5-2.0 1.5-2.6 -

NPK in optimal ratio 1.5-2.0 1.5-3.0 0.8-1.2 -

Manure, 50 t/hа 1.5-3.0 - 1.2-1.5 -

Liming + NPK 1.8-2.7 2.5-4.0 - -

Ceolite, sapropel 1.5-2.5 - 1.5-1.8 -

Ploughing , 35-40 sm 8.0-12 10-16 2.0-3.0 -

Improvement of meadow and pasture

Fundamental 1.5-9.0 4.0-16 1.5-3.5 3.0-5.3

Light 2.0-3.0 2.0-14 2.0-2.5 3.0-5.0

Decrease of radioactive contamination of plant products after countermeasures application, times

The main goal of countermeasures – to decrease individual radiation dose of population

up to normative levels.

The map of contamination territory of Ukraine Cs-137

The irrigation of rice

The irrigation of fodder crops

The river Pripyat

Requirements for the content of radionuclides in the water for irrigation were more stringent than for drinking water.

In Ukraine during the Chernobyl accident a large proportion of products, including rice, produced on

irrigated lands, areas which accounted for 2.4 million hectares.

Although the irrigated lands are located more them 600 km from the Chernobyl zone, migration of Sr-90 with waters of the river Dnepr resulted in increase

the density of soil contamination in the checks and, consequently, the grains of rice a few times.

This made it necessary to create a system for monitoring agricultural areas on irrigated lands and

reduce the irrigation of rice and fodder crops.

20

Dynamics of accumulation of Cs-137 (1) and Sr-90 (2) in the soil rice paddies

kBq/m2

19871988

19901992

19931994

19951996

1997

0

1

2

3

4

5

6

7

Sr-90

Cs-1371987

19881990

19921993

19941995

19961997

0

1

2

3

4

5

6

7

Sr-90

Cs-137

21

Years Bq/kg (n=9, σ ≤ ± 30%)

90Sr 137Cs1972 0.33 2.41982 0.30 0.71985 0.11 0.61986 0.07 1.01987 0.15 1.61988 0.19 1.51989 0.37 1.21990 0.56 0.91991 0.69 1.11992 0.81 1.01993 1.12 0.91994 0.70 2.01995 1.27 1.1

1996 1.30 0.8

Dynamics of radionuclides accumulation in a grain of rice in irrigated paddies after Chernobyl accident

~ 20 times

Action plan for clean milk production

Spatial Distribution analysis of milk contamination levels

Soil and fodder analysis on the territories with high milk

contamination

Development of the countermeasures

Development of supply chain and differentiation of milk processing

according to the contamination levels

Developed three radically different and effective ways to reduce the content of radionuclides in milk and muscle tissue (meat) animals:

first - to reduce radionuclide intake and concentration of radionuclides in milk and meat in

3 - 5 times by adjusting the feed with a low content of Cs – 137;

second - by shifting the radionuclides in the rumen of the ionic state to a bound before it enters the small intestine to prevent its absorption into the blood;

Ferrocine reduced Cs-137 transfer meat and milk by 3-10 times. third - to pre-slaughter fattening "clean" feed. Proved that for fattening animals

clean feed for 40-60 days a large proportion of Cs-137 excreted from the body, and the content of radionuclides in the muscles is reduced by 6-10 times.

Application of zeolite in the feeding period prior to slaughter can have a 2.0-2.4 times decrease the accumulation of Cs-137 in muscle tissue of animals.

Ways to reduce the radionuclide contamination of animal products

Reducing contamination of animal products during the countermeasures

137Cs 90Sr

Countermeasures milk meat milk

Veterinary

The use of Cs-binders

1.5-6.0 1.5-2.1

The use of sorbents 5.0 4.5 1.5 Zootechnical

Pre-slaughter fattening "clean" foods

- 2.0-15

Feed additives 1.2-1.5 1.5-3.1 1.3-1.5 Rational use of

hayfields and pastures 1.5-15 3.0-4.0

Selection of food 2.0 30

25

Radiological efficiency of the ferrocine and feed additives on the basis zeolites

Decrease of concentration 137Cs

Feed additives

Milk Meet Zeolites

Cattle, humolit 2-4 2-3 Cattle, clinoptilolite, stalled keeping 1.22-4.0 1.5-2.9 Cattle, clinoptilolite, grazing 1.5-3.0 1.6-1.7 Rabbits, clinoptilolite 7.8 Broilers, clinoptilolite - 1.9 Broilers, modified, clinoptilolite - 3.8

Ferrocines The salt-lick 2.0-5.0 -

Feed additive to 0.6% 2.4-2.7 1.7-2.9 The introduction of boluses in the rumen 4.0-5.0 -

Countermeasures ensured decrease of Cs-137 content in milk and meat in 4-12 times and allowed to prevent of the

collective dose above 1000 man-Sv in each country.

Decrease of radioactive contamination of milk processing production, times

Product 137Cs 90Sr

Sour cream 1.2-1.3 1.3

Cottage cheese 1.1-1.4increase in

5-6

Hard natural cheeses 2.4increase in

8

Butter 3.6-5.6 1.9-9.1

Dried milk increase in 8increase in

8

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Distribution of settlements by rating doses based on overall dosimetrical pasportization (Ukraine).

The dose, calculated by the content of Cs-137 in milk and potatoes, and their of the daily consumption several times

higher than values calculating dose according to the WBC - monitoring.

This demonstrates the high conservatism of methods for assessing exposure to the population used in the first

period, people's ability to limit the consumption of "dirty" products, as well as a significant decrease in the

consumption of milk and milk products by the population over the last decade. Poor diet can induce health is much

more significant damage than irradiation at low doses.

The question deserves a detailed study and monitoring. Need to develop more adequate models to reduce the conservatism of dose estimates in the long run.

Our proposal on 2012-2013

Topic 1. "Reconstruction of spatial distribution of radiation dose of the thyroid gland (thyroid)

population.“

Rate ratio of I-131 to Cs-137 and its stability in the region of influence of the accident at Fukushima.

Based on the distribution of Cs-137 prediction using the developed mathematical model of ISP NPP and validation

reconstruct data on the density of fallout I-131.

Make a prediction of the spatial distribution of radiation dose thyroid population.

Topic 2. "The organization of land use in the contaminated

area after accident."To monitoring agricultural sphere:

Analyze, and if necessary create a database for monitoring soil and agricultural products.

Conduct comprehensive mapping - levels of pollution and agrochemical properties of soils.

Develop a forecast of contamination of the products in time with the use of models and databases Institute for safety problems NPP.

According to the results highlight the control zone with a different probability of production of specified levels of contamination of products -

milk, vegetables and others.

Identify the most critical landscapes, soils, crops that provide the greatest accumulation of radionuclides on the territory with equal density of

contamination. Optimize system of pollution control products.

Compare data prediction and control of standards and identify areas where intervention is necessary - a change of land use, the countermeasures.

Theme 3. Optimize supply scheme and the sale of products and its technological processing.

Conducting analyze the pattern of supply, processing and use of products from contaminated areas.

Develop a scheme of the targeted supply of products subject to the differencial appointment.

Identify the need for processing of products.

Theme 4. To assess the radiation situation on irrigated lands.

Consider the structure of irrigated land (if any):flood irrigation rice receipts, irrigation , and to evaluate sources of water for irrigation.

According to monitoring data and model calculations to predict the dynamics of water pollution from each source.

Organize control of water sources by chemical composition.

In order to predict contamination of crop production for the type of product and method of irrigation.

Assess the need for countermeasures.

Thank you for the attention!