1

Comparison of the accumulation of 137Cs and 90Sr by Six Spring Wheat varieties

Yuri V. Putyatin1*, Taisa M. Seraya1 , Oksana M. Petrykevich1, Brenda J. Howard2

1Laboratory of Radioecology, Research Institute for Soil Science and Agrochemistry

(BRISSA), Kazintsa str. 62, 220108, Minsk, Belarus.

Email: put@tut.by

Tel: 375 172 120920

Fax: 375 172 120920

2Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue,

Bailrigg, Lancaster LAI 4AP, United Kingdom.

Keywords: 137Cs, 90Sr, bioavailability, genotype, Triticum aestivum, productivity,

concentration ratio, countermeasures

* Corresponding author

Classification : Original paper

2

Abstract The uptake of 137Cs and 90Sr by six varieties of spring wheat (Triticum

aestivum), were compared in field trials on land contaminated by the Chernobyl

accident. All the experimental varieties are officially adopted for agricultural use in

Belarus and are used in large-scale production. Under identical conditions of nutrition,

the productivity of the varieties varied significantly by 1.3 fold. The extent of 137Cs and

90Sr accumulation by wheat grain, quantified as the concentration ratio differed

significantly between varieties by 1.6 fold for both radionuclides. There was a

significant linear positive correlation between 90Sr activity concentration in grain with

that of Ca concentration. The correlation between 137Cs and potassium was significant

for grain but not for straw.

The results suggest that certain varieties of spring wheat used in normal

agricultural practice accumulate less 137Cs and 90Sr into grain than others. Some spring

wheat varieties which accumulated relatively less 137Cs did not also accumulate the

lowest content of 90Sr. Thus, selection of the most suitable variety for cultivation needs

to take into account not only its accumulation of both 137Cs and 90Sr but also the relative

density of soil contamination by both 137Cs and 90Sr of soil in each area. However, one

variety, Quattro, had the lowest uptake of both 90Cs and 137Cs, with Manu consistently

the second lowest uptake for both radionuclides. The reduction efficiency achieved by

the use of these varieties is not as high as that achieved by soil amelioration techniques

in the past. Nevertheless, since there are no additional costs or production losses

associated with these varieties, their use in the contaminated areas is recommended as a

simple, practical and effective contribution to reducing the uptake of both 90Sr and 137Cs

and allowing farmers to produce food-grade grain.

3

Introduction

After the Chernobyl accident, 137Cs and 90Sr have both been of mid-long term

environmental concern due to their long physical half-lives and relatively high

environmental mobility compared to the other long lived radionuclides released.

Agricultural production in Belarus is currently conducted on 1.3 million hectares of land

contaminated by 137Cs at deposition levels varying between 37-1480 kBq m-2. Some of

this land (0.46 million hectares) is also contaminated by 90Sr at deposition levels

varying between 6-111 kBq m-2.

Plant uptake of 137Cs or 90Sr from soil is an important pathway for their entry into

the human food chain and substantially contributes to internal radiation dose following

contamination. Because of the persistent uptake of 137Cs and 90Sr by crops and animals,

there is potential long term exposure to people via the foodchain. For crop plants, the

contamination route may be direct through the ingestion of edible crops, or indirect

through the use of crops as animal feedingstuffs.

In the last nearly two decades there has been a significant amount of effort

devoted to the development of a large range of different countermeasures to reduce the

uptake of radiocaesium into crops, with some effort also devoted to radiostrontium

(Howard and Desmet 1993; Howard et al 2004; Howard et al in press). These

countermeasures largely focus on various treatments of the soil to reduce root uptake.

Because some plant species have a relatively low ability to accumulate radionuclides

one countermeasure approach has been to select crop species with comparatively low

uptake of the contaminant radionuclide (Makarevitch 1973; Korneyeva 1974; Moiseev

et al 1977; Malikov et al 1981; Smolders et al 1993; Krouglov et al 1997; Bogdevitch et

4

al 2001a; Bogdevitch et al 2003b; Vasiluk et al 2001; Buysse et al 1996). Differences in

productivity, the extent of the vegetative period and the mineral nutrition characteristics

of species each influence the extent of radionuclide accumulation both between and

within different plant species (Zhu et al 2000; Tsialtas et al 2003; Waegeneers et al 2001;

Twinning et al 2004; Zheleznov et al 2002). Conversely, the ability of certain plant

species to take up a relatively large amount of certain radionuclides has led to the

suggestion that these species could be used for phytoremediation of contaminated land

(Entry and Watrud 1988; Fuhrmann et al 2002). These approaches has been used in

Belarus, where the cultivation of rapeseed (Brassica napus f.) on contaminated lands

produces safe, edible oil whilst simultaneously decontaminating soil (Bogdevitch et al

2001b; Bogdevitch et al 2001c).

There are relatively few data considering intraspecies variation, compared to that

for interspecies differences in uptake. The selection of different crop varieties has

previously been suggested as a countermeasure in international fora (Alexakhin 1993;

Prister 1992; IAEA 1994). Although Green et al (1996) reported 3-4 fold variation in

uptake of a limited range of varieties they also found a similar variation for the same

variety of crop between years and concluded that (i) the implementation of such a

countermeasure should be based on a comprehensive dataset in which the inherent

variability in transfer factors has been assessed and (ii) combining data from separate

experiments could lead to erroneous conclusions. In a recently produced

countermeasure compendium, variety selection as a countermeasure was not included as

it was felt that there was currently inadequate information to proceed to a consideration

of their potential practical implication (STRATEGY 2003, http://www.strategy-

ec.org.uk). However, the evaluation recommended that the inclusion of this

5

countermeasure should be reviewed if there is any future development and testing of

these countermeasures.

Widespread agrochemical countermeasures applied after the Chernobyl accident

in Belarus, Russia and Ukraine on contaminated agricultural lands have changed the soil

agrochemical properties and decreased radionuclide transfer coefficients from soil to

plants (eg. Putyatin et al 2001; Vasiluk et al 2001). At the present time, most of the

treated soils have higher pH and mobile potassium values than was previously the case.

Because of this, the potential efficiency of further soil amelioration protective measures

used in plant production such as liming and higher rate of potassium fertilization are

reduced.

The climatic and soil conditions of the most highly contaminated southern areas

of Belarus are most suitable for cultivation of wheat to produce food-grade grain. More

than 50% of the contaminated arable lands in Belarus are cultivated with cereals.

Permitted levels (PL) currently in force in Belarus (Bogdevitch et al 2003b; RDU-99

1999) are low compared with international limits and those in force in the EC for future

accidents (CEC 1989). The permitted levels for 90Sr are especially low, at 11 Bq kg-1

for food-grade grain and 3.7 Bq kg-1 for bread, whilst for 137Cs the respective PL values

are higher at 90 and 40 Bq kg-1. Given these low PL values, without countermeasure

application the current contamination levels in many areas led to wheat containing

radiocaesium and radiostrontium above the PL values. Soil contamination of just 11

kBq m-2 of 90Sr leads to problems in producing wheat below the PL values and about

190 000 hectare of agricultural lands are contaminated by 90Sr higher than 11 kBq m-2

producing 17 000 - 30 000 tonnes per year of grain with 90Sr contents exceeding the PL.

As a consequence, a significant proportion of the crop can only be used as forage or

6

processed, but cannot be sold as food-grade grain which has a higher monetary value for

local farmers. Therefore, it is important to identify additional countermeasures

techniques to reduce the levels of contamination of cereals to enable production of food-

grade grain. Alongside the agrochemical countermeasures already used, there is

potential to further reduce 137Cs and 90Sr accumulation in cereals if we can identify crop

rotation varieties with a relatively low uptake of these two radionuclides.

The aim of this study was to compare the uptake of 137Cs and 90Sr by different

officially adopted varieties of spring wheat to try to identify varieties with low uptake

rates. The study was conducted on a Podzoluvisol loamy sand soil which is a

widespread, representative soil in the affected region (46% of arable lands). The

ultimate goal was to provide an effective additional countermeasure to minimize the

flux of 137Cs and 90Sr into the food chain.

Materials and Methods

Field experiment

In a two-year field experiment (2002-2003), six varieties of spring wheat (Triticum

aestivum) from different countries of origin were studied: Rostan (Belarus), Quattro

(Germany), Manu (Finland), Banty (Poland), Daria (Belarus) and Munk (Germany).

The preceding crop in the normal crop rotation scheme is red clover. The standard

spring wheat variety used in Belarus is Rostan, but each of the other varieties are

adopted as suitable for cultivation in Belarus. The concept of a “standard variety” is

used by the State Seed Committee to compare productivity of adopted varieties and

7

every potential new variety with respect to crop yield and quality. If the crop yields of a

new variety is lower than the “standard variety” the new variety will not be adopted.

The experiment was conducted in the Gomel region of Belarus. The surface soil

layer (0-25 cm) of the Podzoluvisol loamy sand soil was characterized by a low content

(14%) of fine fraction particles (< 0.01mm). The agrochemical parameters of the soil

�������������� ����KCl ��������������2�5 197 mg kg-1��������������������������2��

288 mg kg-1 dw, exchangeable Ca 820 mg kg-1 dw and exchangeable Mg 122 mg kg-1

dw. Radionuclide deposition (mean±SD) in soil of 137Cs was 320 ± 19.0 kBq m-2 and

90Sr was 30 ± 4.8 kBq m-2.

Seeds of each of the six varieties were sown in experimental plot areas of 4 m2

and 1 m2 in mid April in both 2002 and 2003. Four replicates was used in a randomized

block design. Fertilizers were applied to the soil before sowing at a rate per m2 of : urea

– 7 g, superphosphate – 7 g �2�5 and potassium chloride – 12 g K2�. Plant samples

were harvested at full maturity (grain and straw) 105 days after germination.

Soil and plant analysis

The following physicochemical parameters were measured in the soil samples using

conventional methods (Sokolov 1975) briefly as follows:

• pH: was determined with a glass electrode in an aqueous suspension of 10 g

of dry soil and 25 ml of 1 N KCl, shaken and left for deposition overnight.

8

• Organic matter: was measured using 0.1 N iron ammonium sulphate titration

with diphenylamine, after combustion of 1 g soil in 0.4 N chromic acid for 5

minutes.

• Mobile P2O5 and K2O: were determined by extraction in 0.2 N HCl in a

ratio1:5, followed by determination using calorimetric and flame emission

spectrophotometer (FES) methods respectively.

• Exchangeable Ca and Mg: were determined by extraction in 1 N KCl in a

ratio 1:2.5, followed by determination using Atomic Absorption

Spectroscopy (AAS).

For the plant samples, potassium was determined by FES and calcium by AAS

after wet combustion with concentrated sulphuric acid and hydrogen peroxide.

Radioactivity measurements

Cs-137 activity concentration: Plant and soil samples were homogenized, dried at

room temperature and put into Marinelli beakers (1.0 l) and measured using gamma

spectrometry (HP-Ge detector Canberra GC4019 in a low-background environment).

The relative uncertainty of 137Cs activity measurement in all samples was < 10%.

Results were calculated for each soil sample both as Bq kg-1 and as kBq m-2, using the

bulk density of soil of 1.50 g cm-3 and plough layer 25 cm.

Sr-90 activity concentration: Plant and soil samples were ashed at 6000C. The 90Sr

activity concentration was determined using the oxalate method with separation of 90Y

(Cherenkov counting). Beta activity was measured in a low level liquid scintillation

9

counter (CANBERRA Tri-Carb 2750LL). Results were calculated for each soil sample

both as Bq kg-1 and as kBq m-2, using the bulk density of soil of 1.50 g cm-3 and a

plough layer of 25 cm.

Data treatment

For radionuclides, it is generally assumed that the activity concentration of a

radionuclide in a plant or plant part, Cp (Bq kg-1, plant dw), is linearly related to its

concentration in the plough-layer of soil, Cs (Bq kg-1dw), i.e.

Cp = CR Cs. (1) The soil-to-plant concentration ratio CR in Eq. (1), (or transfer factor) was determined

as:

CR = soil) ofdw kgper (Bq soil oflayer plough in nuclide of ionconcentratactivity

plant) ofdw kgper (Bqplant in nuclide of ionconcentratactivity (2)

Conventional regression and multivariate statistical analysis for the obtained data

was carried out using the STATISTICA Program, StatSoft Inc. (2001).

Results

Productivity

10

The productivity of the different varieties at final harvest is shown in Figure 1. The

highest grain productivity was found for the Banty and Munk varieties for which the

significantly enhanced yield was 22 % and 13 % (p<0.05) above that of the standard

Rostan variety according to the variance LSD test (Duncan test). The yield of the

Quattro and Manu varieties was similar to that of Rostan, whereas the Daria variety had

a significantly (p<0.05) lower yield than Rostan by 9%. The yield of straw varied from

0.48 up to 0.66 kg m-2 and was highest for the Quattro variety. The lowest ratio of straw

dry matter to grain was found for the Munk variety (0.92), and the highest for the Daria

variety (1.48).

Insert Figure 1.

Radionuclide uptake

The uptake by the Spring wheat varieties (Figure 2) of 137Cs into grain declined in the

following order:

Daria > Rostan > Banty > Munk > Manu > Quattro

and for 90Sr as follows:

Munk > Daria > Banty > Rostan > Manu > Quattro.

The varieties which accumulated least 137Cs were not always those which

accumulated the least 90Sr. The Quattro variety (which had the lowest uptake into grain)

accumulated 137Cs in grain significantly 1.6 fold less than that of the variety with the

highest uptake, Daria. There was a similar significant 1.6 fold difference between the

lowest (Quattro) and highest (Munk) accumulator of 90Sr.

Insert Figure 2. Insert Figure 3.

11

Changes in radionuclide accumulation by wheat grain in our experiment cannot

be explained by diferences in crop yield (and associated dilution). The Quattro variety

accumulated least 137Cs and 90Sr. However, the Daria variety accumulating 60% more

137Cs (Bq kg-1 dw basis) than Quattro but had a productivity only 12% lower than

Quattro. On a similar comparison basis, the Munk Variety accumulating 57% more 90Sr

than Quattro with only a 24% higher productivity.

Clearly, the above data for plant contamination are not directly comparable due to

the varying extent of soil contamination. This difference is removed when considering

the CR values shown in Table 1. The CR values for 137Cs were similar for the Manu,

Banty and Munk varieties and for 90Sr for the Rostan, Quattro and Manu varieties. CR

values for 137Cs in straw were higher than those of grain by an average of 4.5 fold with

variation between varieties of 0.051-0.066, 90Sr CR values for straw were an average of

10 fold higher than grain with variation between varieties of 3.12-4.12.

Insert Table 1. The chemical analysis data shows that higher 134Cs or 90Sr uptake was found for

varieties that accumulated more of their close respective analogues, K and Ca (Figures 4

and 5). The 90Sr activity concentration in both grain and straw was significantly and

positively linearly correlated with Ca concentration (R2 = 0.67 and 0.61 respectively).

The correlation between 137Cs activity concentration and potassium concentration in

grain was significant but lower (R2 = 0.44) than that for 90Sr and Ca, and there was no

significant relationship between 137Cs and potassium in straw (R2 = 0.17).

Insert Figure 4. Insert Figure 5.

The total flux of radionuclide into the wheat has been quantified as the total Bq in

wheat per unit deposition (ie Bq kg-1 dw x kg m-2). The lowest total 137Cs and 90Sr

accumulation in grain per unit area was achieved by the Quattro variety (Table 2). This

12

variety had the lowest proportion of the radionuclides accumulated in the edible part

(grain) compared with the total accumulation by grain and straw. The variety with the

lowest accumulation also had the lowest proportion (%) in the edible part (the grain)

compared to the other varieties and therefore the lowest flux into the foodchain.

Insert Table 2. Calculation of the Tag value (ie Bq kg-1 dw divided by kBq m2) is a commonly

used method to compare Cs uptake based on total deposition rather than a soil

concentration. Values for Tag for the experiment are given in Table 3 to enable later

comparison with literature, especially that from the former Soviet Union where Tag

values are commonly reported.

Insert Table 3.

Discussion

Quantification of transfer to wheat

The CR values measured in our experiment can be compared to other data on 137Cs and

90Sr uptake by cereals from various soil types reviewed by Nisbet and Woodman (2000)

and given in Table 4. The CR values for Cs and grain for our loamy sand soil varied

from 0.01 to 0.016 which were similar to the recommended values for clay and loam of

Nisbet and Woodman (2000). For Sr, the CR range we measured of 0.284 – 0.446 was

slightly higher than the highest recommended values for sand and loam of Nisbet and

Woodman (2000) but well within the 95% confidence intervals. This agreement is

13

perhaps a little surprising given that our deposits are nearly 20 years old and we might

have expected values which were lower than those recommended.

Insert Table 4

Bogdevitch et al (2003a) reported significant variability in 137Cs CR data of spring

wheat grown on sod-podzolic loamy sand soil in 1995 depending on the rates of

potassium fertilizers. Without fertilizers application the CR was 0.009, the CR value

decreased with increasing amounts of fertiliser application (N70P60 - 0.008; N70P60K80 -

0.008; N70P60K160 - 0.006 and N70P60K240 - 0.005).

In the long-term study started in 1987 by Krouglov et al (1997), an initially

observed low 90Sr CR value was measured due to its association with fuel particles,

which subsequently increased with time as the particles dissolved. In the later years of

their observations (1993-1994), when fuel particle dissolution was well established,

their CR values for grain of winter wheat grown on sod-podzolic soils were roughly 12-

15 from straw and 2-3 for grain for 90Sr and less than 1 for both sample types for 137Cs

(values taken from a figure). The 90Sr CR values are higher than those reported here for

a similar soil type (and higher than the 95% confidence intervals reported by Nisbet and

Woodman 2000), possibly because of the gradual release of Sr from the fuel particles

and therefore high transient bioavailability and/or the earlier time period of their

sampling (almost a decade before our experiments).

Tag values for 137Cs and 90Sr for spring wheat grain grown on sod-podzolic loamy

sandy soils collected in 1998-2002 (Bogdevitch et al 2003b), and therefore comparable

to our long term data, were similar to the data reported here. The data of Bogdevitch et

14

al (2003b) were for a mixture of spring wheat varieties grown on Podzoluvisol loamy

sand soils; the 137Cs Tag values for grain were 0.02-0.04 m2 kg-1 x 10-3 depending on

exchangeable potassium (range 140-300 ppm �2�����������90Sr they were 1.13-1.62 m2

kg-1 x 10-3 depending on soil acidity (range 5.1-7.0 pHKCl). The equivalent Tag values

for 90Sr were 20-50 fold higher than 137Cs (Bogdevitch et al 2003b) whereas for our

grain the difference was 21-34 fold. Our Tag values for straw were 47.3 – 75.3 fold

higher for 90Sr compared with 137Cs.

Drobyshevskaya et al (2001) reported significant variability in 90Sr Tag values of

grain of spring wheat grown on Podzoluvisol loamy sand soils depending on the year of

the study with a mean Tag value (m2 kg-1 x 10-3 ) of 0.39: 1997-0.61; 1998 – 0.26;

1999 – 0.48; 2000 – 0.23. There was a general trend of a decline in transfer but not

consistently each year.

In our study, grain and straw 90Sr activity concentrations were linearly positively

correlated with Ca concentration. There was also a correlation between 137Cs and

potassium in grain although it was less strong than that of 90Sr, which is expected due to

potassium regulation by the plants. The relationship between Ca and Sr and of K and

Cs has been reported in the radioecological literature for many different plant species

Increased potassium or calcium concentrations in soil generally (but not always)

decrease the plant uptake of Cs or Sr respectively, often by competitive inhibition by

these analogous essential elements (Shirshov & Shain 1971; Moiseev et al 1977;

Judintseva et al 1981; Malikov et al 1981; Alexakhin & Krouglov 2001; Ehlken and

Kirchner 2002). Furthermore, our results are consistent with other data for wheat, such

as the observed greater influx of radiocaesium when there was a deficiency in soil

15

potassium (Zhu et al 2000) and higher radiocaesium uptake occurred in plant species that

deplete K in the rhizosphere to a larger extent.

Variation in transfer with variety

Alexakhin (1993) and Prister (1992) provided some of the first review comparisons of

the reduction efficiency in radiocaesium uptake by using different varieties of crops.

Alexakhin (1993) reported reduction efficiencies varying from 1.4 to 4.5 for 15 different

varieties of spring wheat thus varying by 3.1 fold (with CR values ranging from 0.015-

0.046 for the period up to 1991). Similarly, Prister (1992) reported a 2.5 fold variation

in transfer for six varieties of spring wheat, with Tag values for grain varying from 0.56

– 1.4 m2 kg-1 x 10-3, and commented that “the selection of specific plant species

matched to specific soil properties and the corresponding levels of contamination, is one

of the most efficient measures for reducing the concentration of radionuclides in

agricultural products”. In the field experiments reported here, under identical conditions

of plant nutrition, the uptake of both 137Cs and 90Sr varied significantly with the

different varieties of spring wheat used.

The maximum difference in concentration ratios for both 137Cs and 90Sr between

varieties was less than that reported by Alexakhin (1993) and Prister (1992) at 1.6 fold.

Some spring wheat varieties which accumulated relatively less 137Cs did not also

accumulate the lowest content of 90Sr. Thus, selection of the most suitable variety for

cultivation needs to take into account not only its ability to uptake both 137Cs and 90Sr

but also the density of soil contamination by both 137Cs and 90Sr of soil in each

cultivated area.

16

The most directly comparable data on variation in uptake with variety is the data

on uptake of 137Cs by winter wheat cultivars reported by Schimmack et al (2004). In a

comprehensive study, they compared the field uptake of 137Cs by grain in 28 different

wheat cultivars at three different sites with different soil types (silty and clayey loams)

in Germany in 1999. Certain cultivars, Flair, Kornett and Previa, had lower 137Cs

uptake compared to the mean of all cultivars at each site. On average, the 137Cs activity

in wheat grains of these cultivars at the three sites was reduced by a factor of 1.7

compared to the cultivar with the highest uptake, whereas at one site this factor was as

high as 3.1 (1.5 and 2.2 at the other 2 sites). The mean CR value for grain also varied

by up to a factor of three both between cultivars within sites and between sites for a

single cultivar. The mean CR values at the three sites were 4.2 x 10-4, 4.9 x 10-4 and 7.5

x 10-4 (ranging from 2.6 x 10-4 to 8.8 x 10-4), showing the importance of soil type, with

no single cultivar showing similar values at all sites. The reported CR values were at the

lower end of the range reported in the review of Nisbet et al (2000) for loamy soils for

wheat grain and are generally at least an order of magnitude lower than those measured

in the Podzoluvisol loamy sand soil in the experiment in Belarus.

The lack of replication at sites for cultivars and the low 137Cs activity

concentrations in the German experiment made statistical analysis of the data somewhat

difficult. The authors noted that there was a need to determine whether the differences

noted between cultivars were due to genotype effects or to intracultivar variation in root

uptake due to different soil conditions. Although not definitively proving the former,

our experiment in Belarus lends weight to the possible genetic basis for the observed

differences, but has not addressed the effect of varying soil type.

17

There have been other experiments reporting variation in uptake of radionuclides

by different varieties of the same crop, some of which are only published in the Russian

language literature. In investigations on different crops grown on leached chernozem

soil, differences in 90Sr uptake by 10 varieties of winter wheat were recorded of up to 2

fold, by 5 varieties of winter barley up to 1.4 fold and by 13 varieties of corn up to 2.5

fold (Malikov et al 1981). For 137Cs accumulation in winter wheat, winter barley and

corn the differences were up to 1.9, 2.5, 3.2 fold respectively and there was no

systematic variation in the uptake of Cs and Sr.

In a separate study by Bogdevitch et al (2001b; 2001c) 32 varieties of spring

rapeseed were compared for their ability to accumulate 137Cs and 90Sr in field trials.

Under identical conditions of nutrition, the differences in 137Cs and 90Sr accumulation

between varieties was greater than that reported here at 2.7 and 4 fold respectively. In

contrast, the uptake of 137Cs and 90Sr by three varieties of soybean grown under

identical field conditions on sod-podzolic loamy sandy soil during a two-year period

(1996-1997) was not significantly different. The lack of difference may have been due

to the close genotypic link between the soybean varieties used in the experiment which

were also from the same country of origin (Vedeneeva et al 2000).

In pot experiments, Shirshov and Shain (1971) reported a maximal 3.9 fold

difference in 90Sr accumulation by 14 varieties of fodder beans; and a 2.1 fold

difference in 2 varieties of pea. For the pea varieties, there was a 1.8 fold difference in

137Cs uptake. The pea variety which accumulated the lowest amount of 90Sr

accumulated the higher amount of 137Cs and vice versa. In these experiments, the

coefficients of variation in radionuclide accumulation by parental forms of plants were

much lower than those of cross-bred plants (Shirshov and Shain 1971).

18

In addition to the above there is other evidence in the literature that both Sr

(Rasmusson et al 1963, 1964, 1967; Smith et al 1963; Pinkas et al 1966; Kleese 1968)

and Cs (Øhlenschlæger et al 1991, 1993) uptake are under genetic control. Current

genetically based investigations on gene control of uptake (eg. Payne et al 2004) and of

molecular mechanisms of Cs uptake by plants (White et al 2003) suggest that it may be

possible in future to select for genotypes with either a low uptake of radionuclides or a

high uptake to facilitate phytoremediation.

Conclusion

The results presented here suggest that selection of certain varieties of spring

wheat accumulate less 137Cs and 90Sr into grain than other officially adopted varieties

used in normal agricultural practice. However, one variety, Quattro, had the lowest

uptake of both 90Cs and 137Cs, with Manu consistently the second lowest uptake for both

radionuclides. The reduction efficiency achieved by the use of these varieties is not as

high as that achieved by soil amelioration techniques in the past. Nevertheless, since

there are no additional costs or production losses associated with these varieties, their

use in the contaminated areas is recommended as a simple and effective additional

contribution to reducing the uptake of both 90Sr and 137Cs. It is particularly important to

introduce varieties with minimal accumulation of 137Cs and 90Sr on farmland as an

additional countermeasure where it is now not possible to achieve further significant

reductions using traditional countermeasures such as liming and potassium fertilizers

alone. For farmers in contaminated areas, it is important to be able to grow food-grade

grain under the relevant PL values to maximize their income.

19

Our results, together with other relevant literature suggest that transfer can vary

with different genotypes of the same species to a sufficient extent to make variation in

crop variety a credible countermeasure. In spite of the fact that differences in

radionuclides uptake amongst some varieties are much less than those between species,

there is some benefit to be gained at no additional cost or inconvenience from selecting

varieties with minimum ability of radionuclide accumulation for cultivation on

contaminated soils.

References

Alexakhin, RM (1993) Countermeasures in agricultural production as an effective

means of mitigating the radiological consequences of the Chernobyl accident. Sci Tot

Environ 137:9-20

Alexakhin RM, Krouglov, SV (2001) Soil as the main compartment for radioactive

substances in terrestrial ecosystems. In: Brechignac F, Howard BJ (eds) Radioactive

pollutants: impact on the environment and humans. EDP Science, Les Ulis pp149 – 174

Bogdevitch IM, Shmigelskaya ID, Efimova IA, Putyatin YV (2001a) The volumes of

137Cs and 90Sr accumulation per species and variety of agricultural plants. Proceedings

of Academy of Agrarian Sciences of Belarus 2:40-45 (in Russian)

Bogdevitch I, Putyatin Yu, Rigney C, Chupov A (2001b) Edible Oil Production from

Rapeseed Grown on Contaminated Lands. In: Innovation Forum: Value chains in the

20

processing of renewable raw materials, 10-11 December 2001, Gardelegen, Germany,

BMB+F, Magdeburg, pp 148 - 156

Bogdevitch YM, Putyatin YW, Spaar D (2001c) Die Aufnahme von 137Cs und 90Sr

durch vershiedene Sommerraps genotypen aus dem Boden. Archiv fur Acker-und

Pflanzenbau und Bodenkunde 46:371-383 (in German)

Bogdevitch IM, Tarasiuk SV, Shmigelskaya ID, Seraya TM, Putyatin YV, Efimova IA,

Ochkovskaya LV (2003a) Yield and 137Cs and 90Sr accumulation by crops depending on

rates of potassium fertilizers. Soil investigation and fertilizer application 27:158-169 (in

Russian)

Bogdevitch IM (ed) (2003b) Guide for agricultural practice on lands contaminated by

radionuclides in the Republic of Belarus. RNIUP “Institute of Radiology”, Minsk, pp76

(in Russian)

Buysse J, Ven den Brande K, Merckx R (1996) Genotypic differences in the uptake and

distribution of radiocaesium in plants. Pl Soil 178:265-271

CEC (1989) Council Regulation (Euratom) No. 2218/89 amending Regulation

(Euratom) No. 3954/87 laying down maximum permitted levels of radioactive

contamination of foodstuffs and feedingstuffs following a nuclear accident or any other

case of radiological emergency. Off J Eur Commun L211/1

21

Drobyshevskaya VV, Timofeyev SF, Bondarenko TV (2001) Dependence of 90Sr

accumulation by cereals from nutrient condition of plants. Problems of radiology of

contaminated territories. 1, RNIUP, Gomel, pp 23 - 26 (in Russian)

Entry JA, Watrud LS (1998) Potential remediation of 137Cs and 90Sr contaminated soil

by accumulation in Alamo Switchgrass. Wat Air Soil Pollut 104:339-352

Ehlken S, Kirchner G (2002) Environmental processes affecting plant root uptake of

radioactive trace elements and variability of transfer factor data: a review. J Environ

Radioact 58: 97-112

Fuhrmann M, Lasat MM, Ebbs SD, Kochian LV, Cornish J (2002) Uptake of cesium-

137 and strontium-90 from contaminated soil by three plant species; application for

phytoremediation. J Environ Qual 31:904-909

Green N, Wilkins BT, Hammond DJ, Davidson MF (1996) Transfer of radionuclides to

crops in an area of land reclaimed from the sea. J Environ Rad 31:171-187

Howard BJ, Desmet GM (1993) REACT: Relative Effectiveness of Agricultural

Countermeasure Techniques. Sci Tot Environ 137

Howard BJ, Liland A, Beresford NA, Andersson KG, Cox G, Gil JM, Hunt J, Nisbet A,

Oughton D, Voigt G (2004) A Critical Evaluation of the Strategy Project. Rad. Prot.

Dosim 109: 63-67

22

Howard BJ, Beresford NA, Nisbet A, Cox G, Oughton D, Hunt J, Alvarez B, Andersson

KG, Liland A, Voigt G (in press) The STRATEGY project: decision tools to aid

sustainable restoration and long-term management of contaminated agricultural

ecosystems. J. .Environ Rad

International Atomic Energy Agency (IAEA) (1994) Guidelines for Agricultural

Countermeasures following an Accidental Release of Radionuclides. Technical reports

Series No. 363. International Atomic Energy Agency/Food and Agriculture

Organization, Vienna

Judintseva EV, Pavlenko LI, Zjulikova AG (1981) Soil properties and 137Cs uptake by

crop yield Agrochem 3:86-93 (in Russian)

Kleese RA (1968) Scion control of genotypic differences in Sr and Ca accumulation in

soybeans under field conditions. Crop Sci 8:128-129

Korneyeva NV (1974) Influence of specie and variety peculiarities of plants on 90Sr

accumulation by yield of spring wheat and pea. Abstract of PhD thesis, Moscow

University, Moscow 19p (in Russian)

Krouglov SV, Filipas AS, Alexakhin RM, Arkhipov NP (1997) Long-term study on the

transfer of 137Cs and 90Sr from Chernobyl-contaminated soils to grain crops. J Environ

Radioact 34:267-286

23

Makarevitch KI (1973) 90Sr accumulation by wheat, oats, and peas yield on different

soils: Abstract of PhD thesis. Moscow University, Moscow 18 p (in Russian)

Malikov VG, Perepeliatnikova LV, Djukov BI (1981) Species and variety differences of

plants in 137Cs and 90Sr accumulation from soil. Agrochem 8:94-98 (in Russian)

Moiseev IT, Tikhomirov FA, Rerikh LA (1977) Influence of varieties particulars of

wheat and peas on 137Cs and potassium accumulation by yield. Proceedings of Moscow

university, Soil Sci 3:105-109 (in Russian)

Nisbet AF, Woodman RFM (2000) Soil-to-plant transfer factors for radiocesium and

radiostrontium in agricultural systems. Hlth Phys 78:279-288

Øhlenschlæger M, Gissel-Nielsen G (1991) Differences in the ability for barley and rye

grass varieties to absorb caesium through the roots. Acta Agriculturae Scandinavica

41:321-328

Øhlenschlæger M, Gissel-Nielsen G, Nielsen SP (1993) Differences in the sensitivity of

barley varieties to direct cesium contamination from the Chernobyl accident. Hlth Phys

64:535-537

Payne KA, Bowen HC, Hammond JP, Hampton CR, Lynn JR, Mead A, Swarup K,

Bennett MJ, White P, Broadley MR (2004) Natural genetic variation in caesium (Cs)

accumulation by Arabidopsis thaliana. New Phytol 162:535-548

24

Pinkas LLH, Smith LH (1966) Physiological basis of differential strontium

accumulation in two barley genotypes. Plant Physio 41:1471-1475

Prister B, Loshchilov N, Perepelyatnikova G, Perepelyatnikov G, Bondar P (1992)

Efficiency of measures aimed at decreasing the contamination of agricultural products

in areas contaminated by the Chernobyl NPP accident. Sci Tot Environ 112:79-87

Putyatin YV, Shmigelskaya ID, Efimova IA (2001) Influence of agrochemical soil

properties upon 90Sr uptake by grain crops. Soil invest fert applic 26:261-269 (in

Russian)

Rasmusson DC, Smith LH, Myers WM (1963) Genetic control of strontium

accumulation in barley, wheat and soybeans. Crop Sci 3:34-37

Rasmusson DC, Smith LH, Kleese RA (1964) Inheritance of Sr-89 accumulation in

wheat and barley. Crop Sci 4:586-589

Rasmusson DC, Kleese RA (1967) Isogenicanalysis of Sr-89 accumulation in barley.

Crop Sci 4:617-619

RDU-99 (1999) Republican permitted levels of radioactive contamination of foodstuffs

and water. Belorussian sanitary standard No. 10-117-99.

25

Schimmack W, Zimmermann G, Sommer M, Dietl F, Schultz1 W, Paretzke1 HG (2004)

Soil-to-grain transfer of fallout 137Cs for 28 winter wheat cultivars as observed in field

experiments. Radiat Environ Biophys 42:275-284

Shirshov VA, Shain SS (1971) Variety peculiarities of leguminous crops on 90Sr and

137Cs accumulation by yield. Agrochem 9:107-112 (in Russian)

Smith LH, Rasmusson, DC, Myers WM (1963) Influence of genotype upon relationship

of strontium-89 to calcium in grain of barley and wheat. Crop Sci 3:34-37

Smolders E, Merckx, R (1993) Some principles behind the selection of crops to

minimize radionuclide uptake from soil. Sci Tot Environ 137:135-146

Sokolov AV, (ed) (1975) Agrochemical methods of soil testing. Nauka, Moscow (in

Russian)

StatSoft Inc. (2001) STATISTICA Program. CD Statistica ’99 Edition, Kernel release

5.5A, StatSoft Inc� 1984-1999 http://www.statsoft.com accessed 1st June 2005

STRATEGY project (2003) http://www.strategy-ec.org.uk accessed 1st June 2005

Tsialtas J, Matsi T, Barbayiannis N, Sdrakas A, Veresoglou DS (2003) Strontium

absorption by two Trifolium species as influenced by soil characteristics and liming.

Wat Air Soil Pollut 144:363-373

26

Twinning JR, Payne TE, Itakura T (2004) Soil-water distribution coefficients and plant

transfer factors for 137Cs and 90Sr under field conditions in tropical Australia. J Environ

Radioact 71:71-87

Vasiluk GV, Putyatin YV, Shmigelskaya ID (2001) Liquidation of consequences of

Chernobyl accident in agrarian and industrial complex of Belarus. Agrochemical

Bulletin, Moscow 3:12-16 (in Russian)

Vedeneeva TV, Putyatin YuV, Seraya TM, Tarasiuk SV, Davydenko OD, Ageyets VYu

(2000) Perspectives of legume crop cultivation for a grain on sod-podzolic loamy sand

soils contaminated by radionuclides. Soil Sci Agrochem 31:148-155 (in Russian)

Waegeneers N, Camps M, Smolders E, Merckx R (2001) Genotypic effects in

phytoavailability of radiocaesium are pronounced at low K intensities in soil. Pl Soil 235 1:11-

20

White PJ, Swarup K, Escobar-Gutierrez AJ, Bowen H, Willey N, Broadley MR (2003)

Selecting plants to minimize radiocaesium in the food chain. Pl Soil 249:177-186

Zheleznov AV, Zheleznova NB, Smetanin NI, Sukhanovskaya VS (2002)

Intrapopulation variability of some meadow plant species in respect of their ability to

accumulate 90Sr. Russian Journal of Genetics 38:521-525 (In Russian).

27

Zhu YG, Shaw G, Nisbet AF, Wilkins BT (2000) Effect of potassium starvation on the

uptake of radiocaesium by spring wheat (Triticum aestivum cv. Tonic) Pl Soil 220:27-

34

28

Table 1 Concentration ratio (CR) of 137Cs or 90Sr of spring wheat varieties (mean ±SD)

CR 137Cs 90Sr

Variety

Grain Straw Grain Straw Rostan 0.015 ±0.0013 0.062 ±0.0044 0.324 ±0.0311 3.16 ±0.2652 Quattro 0.010 ±0.0011 0.051 ±0.0055 0.284 ±0.0307 3.62 ±0.2604 Manu 0.012 ±0.0012 0.066 ±0.0040 0.304 ±0.0292 3.12 ±0.2616 Banty 0.013 ±0.0012 0.061 ±0.0044 0.375 ±0.0316 3.58 ±0.2580 Daria 0.016 ±0.0013 0.064 ±0.0046 0.395 ±0.0332 3.74 ±0.2688 Munk 0.013 ±0.0011 0.055 ±0.0053 0.446 ±0.0374 4.12 ±0.2964

29

Table 2 Total 137Cs and 90Sr flux per unit area into grain and straw by different spring

wheat varieties

137Cs accumulation, Bq m-2 90Sr accumulation, Bq m-2 Variety Grain Straw Total Edible part

% Grain Straw Total Edible part

% Rostan 6 28 34 18 12 134 146 8 Quattro 4 29 33 13 11 191 202 5 Manu 5 28 33 15 12 125 137 9 Banty 6 31 37 17 17 169 186 9 Daria 6 34 40 15 13 185 199 7 Munk 6 22 28 21 19 158 177 10

30

Table 3 Tag values (m2 kg-1 x 10-3) for 137Cs and 90Sr flux into grain and straw by

different spring wheat varieties (mean ± SD)

Tag value (m2 kg-1) 137Cs 90Sr

Variety

Grain Straw Grain Straw Rostan 0.041 ±0.0034 0.165 ±0.0119 0.86 ±0.086 8.43 ±0.767 Quattro 0.027 ±0.0029 0.135 ±0.0146 0.76 ±0.085 9.65 ±0.753 Manu 0.032 ±0.0031 0.176 ±0.0105 0.81 ±0.081 8.32 ±0.758 Banty 0.035 ±0.0034 0.162 ±0.0117 1.00 ±0.088 9.54 ±0.744 Daria 0.043 ±0.0036 0.170 ±0.0123 1.05 ±0.092 9.97 ±0.778 Munk 0.035 ±0.0030 0.146 ±0.0140 1.19 ±0.104 11.00 ±0.858

31

Table 4 Recommended CR values for radiocaesium and radiostrontium transfer to

edible crop parts for cereals with 95% confidence intervals (Nisbet and Woodman 2000)

Soil type n CR value (Bq kg-1 dw per Bq kg-1 dw soil)

Recommended value 95% Confidence intervals Radiocaesium Sand 208 0.021 0.0017 0.25 Loam 358 0.014 0.00045 0.42 Clay 49 0.011 0.00057 0.21 Organic 54 0.043 0.0038 0.49 Radiostrontium Sand 112 0.23 0.03 1.7 Loam 88 0.15 0.022 0.94 Clay 21 0.071 0.022 0.23 Organic 7 0.03 0.0074 0.12

32

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Rostan Quattro Manu Banty Daria Munk

Variety

Yie

ld, d

w (

kg m

-2)

grain straw

Fig. 1 Putyatin

33

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

Rostan Quattro Manu Banty Daria Munk

Variety

137 C

s, B

q kg

-1, d

wGrain Straw

Fig. 2 Putyatin

34

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

Rostan Quattro Manu Banty Daria Munk

Variety

90Sr

, Bq

kg-1

, dw

Grain Straw

Fig. 3 Putyatin

35

10.0

60.0

110.0

160.0

210.0

260.0

310.0

Rostan Quattro Manu Banty Daria Munk Variety

90S

r, B

q kg

-1, d

w

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Ca,

%,

dw

�������� ��������� 90Sr in grain 90Sr in straw

Fig. 4 Putyatin

36

0.0

10.0

20.0

30.0

40.0

50.0

60.0

Rostan Quattro Manu Banty Daria Munk Variety

0

0.5

1

1.5

2

2.5

3

K2O

, %, d

w

�2������� �2�������� 137Cs in grain 137Cs in straw

137 C

s, B

q kg

-1, d

w

Fig. 5 Putyatin

37

Figure legends: Fig. 1 Variation in the productivity of the six spring wheat varieties (mean ± LSD05) Fig. 2 137Cs activity concentrations of the six spring wheat varieties (mean field soil deposition was 320 kBq m-2 of 137Cs ) (mean ± LSD05) Fig. 3 90Sr activity concentrations of the six spring wheat varieties (mean field soil deposition was 30 kBq m-2 of 90Sr ) (mean ± LSD05) Fig. 4 Comparison between calcium (%, mean ± LSD05) and 90Sr (Bq kg-1) content in grain and straw of spring wheat varieties Fig. 5 Comparison between potassium (%, mean ± LSD05) and 137Cs (Bq kg-1) content in grain and straw of spring wheat varieties