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Change in land use and crop selection
The Science of the Total Environment. 137 (1993) 169-172 Elsevier Science Publishers B.V., Amsterdam
169
Change in land use and crop selection R.M. Alexakhin a, M.J. Frissel b, E.H. Schulte ~, B.S. Pristerd, V.A. Vetrov ~ and B.T.Wilkins f aRussian lnstituw of Agricultural Radiology and Agroecology. Kievskoe Shosse. Obninsk 249020. Kaluga Regioa. Russian Federation bLaboratory for Radiation Research, RIVM. PO Box !. NL-3720 BA Bilthoven. Netherlands ¢CEN de Cadarache, BP !. F-13108 St PauMez-Durance Ct~dex. France aUkrainian Academy of Agricultural Sciences. Suvorova Str.. 9. Kiev. 252010. Ukraine elnternational Aton,~.c Energy Agency, Wagramerstr. 5. PO Box !00. A.1400 Vienna. Austria fNational Radio(ogical Protection Board. Chiiton. Didcot. Oxon OXIi ORQ. UK
ABSTRACT This paper summarises briefly the discussi,~,ls that took place within the REACT working group on the role of changes in land use and crop .~election in agricultural countermeasures. It emphasises that the choice of the most suitable counte.-measure should take into account not only the total dose saved but also the economic, social and e~ologieal implications.
Key words: radionuclide~: countermeasures; land use; crops; agriculture
EFFECT OF CHANGES IN LAND USE AND CROP SELECTION
Change in land use as a countermeasure is the modification of existing agricultural practice such that the products from that land are radiologically acceptable. Such changes may vary enormously both in the effect that they can have on doses to people and in their impact on the ecology of the affected area. For example, the effects of a change in the variety of a given species would be much less than those resulting from substantial changes in the type of crop. Radical changes in land use such as the substitution of cereals for vegetable crops are relatively drastic compared to measures such as the addition of fertilisers or other soil treatments or the improvement of meadows or pasture. Some changes will necessafiiy be in place for many years and although the radiologicai benefits might conti~'~ue thro:~ghout this period, economic, social and ecological conseq?~¢nces could accrue over these timescales. As a result, substantial changes in land u,~e would only be con-
| 70
R.M. ALEXAKHIN El" AL.
sidered when other less stringent measures have been found to I~e or are expected to be insufficiently effective. Depending upon the information available, the decision to make such a change might therefore not be taken until some years after the contamination has occurred. Within an affected area, the selection of the most appropriate agricultural countermeasure would take acce,unt of the radionuclide composition of the deposit and in particular, the presence of long-lived radionuclides such as 9°Sr, '37Cs, 23sPu and 239'24°puand their deposition in different parts of the affected area. Fer those parts where changes in land use are considered to be the most appropriate option, the following factors need to be evaluated.
1. The a~ricultural limitations of the affected land, in order to determine those crops and practices that the land can support. 2. The economic, social and ecological implications of each of the possible changes. 3. The changes in projected doses that each of these measures would have for those who live and work on the affected land, taking account of
TABLE ! Impact and effectiveness of changing land use Change
Reduction factor ~
Social ar.d economic consequ:;lces
Selection of other varieties of same crop Selection of other, but comparable crops Green vegetables to cereals Cereals to edible industrial crops, e,g,, sugarbects, oil seed Cereals to non-edible industrial crops, eg, flax Arable to cattle syster. Sheep, goats to cattle Dairy to meat system Arable system to forestry Cattle system to forestry
up to 2-4
very low
up to 2-3
low
up to factor of 5 >>a factor of 10
high low
>>a factor of 10
low
factor of !0 to 100 up to factor l0 highly dependent on technological possibilities >>a factor of I00 >>a factor of 100
rather high low low
aReduction factor = activity concentration in akc~-~ative product activity concentration in original product
extremely high extremely high
CHANGE IN LAND USE AND CROP SELECTION
1'71
all exposure pathways. Thus, for example, exten~al irradiation and inhalation of resuspended material would be considered as well as foodchains. Different changes in !and use can be simply compared from the quotients of the activity concentrations in the alternative products to those that would have resulted in the original products if the land use practices remained unchanged. Some illustrations of this approach are given in Table 1. However, the overall radiological effect of these changes should not be estimated solely on the basis of reductions in activity concentrations, but rather in terms of the total dose saved. For example, the introduction of forestry might essentially eliminate doses from the foodchain, but for people working on tile affected land, the changes in potential doses from other exposure pathways would need to be taken into account. Table I also contains a qualitative evaluation of the social and economic consequences of each of these measures. For example, a change from green vegetables to cereals would be costly not only because of the need to purchase additional machinery, but also because of the reduction in the number of people needed to work on the land and because of the much lower market value per unit area of cereal crops compared to vegetables. Loss of employment is an important factor to take into account and, for example, would be the main contributor to the high costs associated with the introduction of forestry. This Table is purely illustrative and takes no account of ~ny ecological constraints. In certain circumstances therefore, such changes may not be practicable. A comparison of the effectiveness of different agricultural ~ounter~ measures is contained within a paper in these proceedings (Alexakhin, 1993). The paper draws on results from a 5-year experimental and field investigation that has been carried out in the affected area around the Chernobyl nuclear power plant. For ~37Cs, soil treatments such as the application of potassium fertiliser gave reductions in activity concentrations that were typically a factor of about 2 for a r~;~ngeof crops grown in soils with varying degrees of fertility. Improvements in pasture, using measure~ such as ploughing, liming or the ad~'tion of organic or inorganic fertilisers, gave reductions in act'4ity concentrations in i,,,,bage of up to a factor of about 8. The importance of-,,op selection was evidenced from a study in which soil:plant transfer factors were determined for several different varieties of some important vrops. For cereal crops, transfer factors for individual species typically varied by factors of about 3. Similar results were observed for other crop~ such as potatoes~ tomatoes and clover. The variabiliJy in soil:plant tran~f~c factors between species was, as expected, somewhat greater, being up to a factor of 10. The conclusions in this paper are supported by results published sub~eque~:t to tiiis wol"kshop for parts of the Ukraine
172
a.M ALEX^ginS~r ^L
that were affected by the Chernobyl accident (Prister et al., 1992). These repots of practical experience in agricultural systems in affected areas confirm that change of land use, including crop selection, is an important consideration in the selection of the mogt appropriate countermeasure, especially when dealing with long-term consequences. REFERENCES
Alexakhin, R.M., 1993. Countermeasures in agricultural production as an effective means of mitigating the radiological consequences of the Chernobyl accident. Sci. Total Environ., 137:9-21 Prister B.S., N. Loshchilov, L. Perepelyatnikova, G. Perepeiyatnikov and P. Bondar, 1992. Efficiency of measures aimed at decreasing the contamination of agricultural products in areas contaminated by the Chernobyl NPP accident. Sci. Total Environ., 112: 79-87.
169
Change in land use and crop selection R.M. Alexakhin a, M.J. Frissel b, E.H. Schulte ~, B.S. Pristerd, V.A. Vetrov ~ and B.T.Wilkins f aRussian lnstituw of Agricultural Radiology and Agroecology. Kievskoe Shosse. Obninsk 249020. Kaluga Regioa. Russian Federation bLaboratory for Radiation Research, RIVM. PO Box !. NL-3720 BA Bilthoven. Netherlands ¢CEN de Cadarache, BP !. F-13108 St PauMez-Durance Ct~dex. France aUkrainian Academy of Agricultural Sciences. Suvorova Str.. 9. Kiev. 252010. Ukraine elnternational Aton,~.c Energy Agency, Wagramerstr. 5. PO Box !00. A.1400 Vienna. Austria fNational Radio(ogical Protection Board. Chiiton. Didcot. Oxon OXIi ORQ. UK
ABSTRACT This paper summarises briefly the discussi,~,ls that took place within the REACT working group on the role of changes in land use and crop .~election in agricultural countermeasures. It emphasises that the choice of the most suitable counte.-measure should take into account not only the total dose saved but also the economic, social and e~ologieal implications.
Key words: radionuclide~: countermeasures; land use; crops; agriculture
EFFECT OF CHANGES IN LAND USE AND CROP SELECTION
Change in land use as a countermeasure is the modification of existing agricultural practice such that the products from that land are radiologically acceptable. Such changes may vary enormously both in the effect that they can have on doses to people and in their impact on the ecology of the affected area. For example, the effects of a change in the variety of a given species would be much less than those resulting from substantial changes in the type of crop. Radical changes in land use such as the substitution of cereals for vegetable crops are relatively drastic compared to measures such as the addition of fertilisers or other soil treatments or the improvement of meadows or pasture. Some changes will necessafiiy be in place for many years and although the radiologicai benefits might conti~'~ue thro:~ghout this period, economic, social and ecological conseq?~¢nces could accrue over these timescales. As a result, substantial changes in land u,~e would only be con-
| 70
R.M. ALEXAKHIN El" AL.
sidered when other less stringent measures have been found to I~e or are expected to be insufficiently effective. Depending upon the information available, the decision to make such a change might therefore not be taken until some years after the contamination has occurred. Within an affected area, the selection of the most appropriate agricultural countermeasure would take acce,unt of the radionuclide composition of the deposit and in particular, the presence of long-lived radionuclides such as 9°Sr, '37Cs, 23sPu and 239'24°puand their deposition in different parts of the affected area. Fer those parts where changes in land use are considered to be the most appropriate option, the following factors need to be evaluated.
1. The a~ricultural limitations of the affected land, in order to determine those crops and practices that the land can support. 2. The economic, social and ecological implications of each of the possible changes. 3. The changes in projected doses that each of these measures would have for those who live and work on the affected land, taking account of
TABLE ! Impact and effectiveness of changing land use Change
Reduction factor ~
Social ar.d economic consequ:;lces
Selection of other varieties of same crop Selection of other, but comparable crops Green vegetables to cereals Cereals to edible industrial crops, e,g,, sugarbects, oil seed Cereals to non-edible industrial crops, eg, flax Arable to cattle syster. Sheep, goats to cattle Dairy to meat system Arable system to forestry Cattle system to forestry
up to 2-4
very low
up to 2-3
low
up to factor of 5 >>a factor of 10
high low
>>a factor of 10
low
factor of !0 to 100 up to factor l0 highly dependent on technological possibilities >>a factor of I00 >>a factor of 100
rather high low low
aReduction factor = activity concentration in akc~-~ative product activity concentration in original product
extremely high extremely high
CHANGE IN LAND USE AND CROP SELECTION
1'71
all exposure pathways. Thus, for example, exten~al irradiation and inhalation of resuspended material would be considered as well as foodchains. Different changes in !and use can be simply compared from the quotients of the activity concentrations in the alternative products to those that would have resulted in the original products if the land use practices remained unchanged. Some illustrations of this approach are given in Table 1. However, the overall radiological effect of these changes should not be estimated solely on the basis of reductions in activity concentrations, but rather in terms of the total dose saved. For example, the introduction of forestry might essentially eliminate doses from the foodchain, but for people working on tile affected land, the changes in potential doses from other exposure pathways would need to be taken into account. Table I also contains a qualitative evaluation of the social and economic consequences of each of these measures. For example, a change from green vegetables to cereals would be costly not only because of the need to purchase additional machinery, but also because of the reduction in the number of people needed to work on the land and because of the much lower market value per unit area of cereal crops compared to vegetables. Loss of employment is an important factor to take into account and, for example, would be the main contributor to the high costs associated with the introduction of forestry. This Table is purely illustrative and takes no account of ~ny ecological constraints. In certain circumstances therefore, such changes may not be practicable. A comparison of the effectiveness of different agricultural ~ounter~ measures is contained within a paper in these proceedings (Alexakhin, 1993). The paper draws on results from a 5-year experimental and field investigation that has been carried out in the affected area around the Chernobyl nuclear power plant. For ~37Cs, soil treatments such as the application of potassium fertiliser gave reductions in activity concentrations that were typically a factor of about 2 for a r~;~ngeof crops grown in soils with varying degrees of fertility. Improvements in pasture, using measure~ such as ploughing, liming or the ad~'tion of organic or inorganic fertilisers, gave reductions in act'4ity concentrations in i,,,,bage of up to a factor of about 8. The importance of-,,op selection was evidenced from a study in which soil:plant transfer factors were determined for several different varieties of some important vrops. For cereal crops, transfer factors for individual species typically varied by factors of about 3. Similar results were observed for other crop~ such as potatoes~ tomatoes and clover. The variabiliJy in soil:plant tran~f~c factors between species was, as expected, somewhat greater, being up to a factor of 10. The conclusions in this paper are supported by results published sub~eque~:t to tiiis wol"kshop for parts of the Ukraine
172
a.M ALEX^ginS~r ^L
that were affected by the Chernobyl accident (Prister et al., 1992). These repots of practical experience in agricultural systems in affected areas confirm that change of land use, including crop selection, is an important consideration in the selection of the mogt appropriate countermeasure, especially when dealing with long-term consequences. REFERENCES
Alexakhin, R.M., 1993. Countermeasures in agricultural production as an effective means of mitigating the radiological consequences of the Chernobyl accident. Sci. Total Environ., 137:9-21 Prister B.S., N. Loshchilov, L. Perepelyatnikova, G. Perepeiyatnikov and P. Bondar, 1992. Efficiency of measures aimed at decreasing the contamination of agricultural products in areas contaminated by the Chernobyl NPP accident. Sci. Total Environ., 112: 79-87.