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Radiocaesium contents of meat in Italy after the Chernobyl accident and their changes during the cooking process
J. Environ. Radioactivity 12 (1990) 179--183
Technical Note Radiocaesium Contents of Meat in Italy After the Chernobyi Accident and Their Changes During the Cooking Process
ABSTRACT Levels of radioactive contamination in meat have been studied, along with ways of decreasing them. Specifically, radiocaesium concentrations in a range of samples of different types of meat collected throughout Italy since April 1986 are presented here. The samples are of beef, lamb, pork, chicken, turkey and rabbit. It was found that the radiocaesium content of lamb is higher than that in any of the other meat types considered here. Studies of the decrease in the radiocaesium content of meat during cooking showed that, when the meat is cooked in salt water (1%), the activity decreases by as much as 80% relative to uncooked samples.
INTRODUCTION The study of radionuclides in the food chain dates back some 30 years to the first report on the Effects of Atomic Radiation published in 1958 ( U N S C E A R , 1958). The early studies were mainly on the contamination of foodstuffs from fallout from atmospheric nuclear weapon tests. More recently, the nuclear accident at the Chernobyl Unit 4 reactor has provided a unique opportunity to study these processes on a large scale. The accident involved release of some 1018Bq of radionuclides of potential significance to the human food chain (Zifferero, 1988). During the past three years, hundreds of articles have been published on various aspects of this accident (Bujdoso, 1987, 1988). Many countries have established new radiation protection research programmes or have accelerated existing programmes (Burkart, 1989). In the process, considerable attention has been paid to food chain contamination 179 J. Environ. Radioactivity 0265-931X/90/$03.50 © 1990 Elsevier Science Publishers Ltd, England. Printed in Great Britain
180
Lotfi et al.
following this release of radionuclides to the environment (Piesch & Duftschmid, 1987; YRPA, 1987; Carter, 1988; CEN, 1988; ESNA, 1988). In the Italian adult diet, meat comprises on average about 14% of the consumption of main foodstuffs, the others being milk and milk products (22%), green leafy vegetables (13%), bread and pasta (26%), fish (2%) and fruit (23%) (NEA, 1987). It is therefore important to determine the radioactivity concentrations in different types of meat in order to evaluate the effective dose equivalent (EDE) received through meat consumption. The total radiocaesium concentrations of different foodstuffs in Italy and the resultant individual EDE commitment using food basket studies have been reported elsewhere (IAEA, 1989a). This paper describes the results of measurements of the radiocaesium concentrations in several samples of meat collected from throughout Italy since April 1986. The reduction in radiocaesium content of the samples as a result of cooking has also been studied.
MATERIALS AND METHODS The measurements were carried out by gamma-spectrometry using 450 ml Marinelli beakers and 30% HPGe detectors with a detection limit of <1 Bq/kg. The samples were of beef, lamb, pork, chicken, turkey and rabbit. A total of 377 samples was analysed and the concentrations of both 134Cs and 137Cs were determined. Of these, some 175 samples were from 1986, 108 from 1987 and the remainder from 1988.
RESULTS AND DISCUSSION Figure 1 shows the frequency histogram of the total radiocaesium contents of all the meat samples measured. One-third of the samples had radiocaesium concentrations below the lower limit of detection (LLD) of 1 Bq/kg. The results show that 65% of the samples of radiocaesium content above the LLD have concentrations of less than 50 Bq/kg. Those with concentrations in the range 50 to 100 Bq/kg comprise about 15% of the total. The weighted mean of the radiocaesium concentrations of all the samples is about 75 Bq/kg. The trend in the frequency of total radiocaesium contents from 1986 to 1988 is shown in Fig. 2. Analysis of the results shows that the radiocaesium content of lamb is higher than those of the other types of meat considered here. The highest radiocaesium concentration, of 1960 Bq/kg, was observed in a sample of lamb, another two samples of this type of meat having concentrations of
Radiocaesium contents of meat after the Chernobyl accident
181
Frequency(%) 70~ 60
50 40 30 20 10 0
50
l oo 15o 2o0 2so ~
~
4o0 45o soo
9o0
2o0o
Total C a e s i u m Activity (Bq/kg) il
1986-s8
Fig. 1. Frequency histogram of the total radiocaesium activities of all meat samples.
Frequency(%) 100 , [
8o!
4060020 h
L
in I1~ l, =-~ ==J = ~
J
J -, m
so
loo
1so 200 2so
300 350 400 4so soo
900
2000
Total C a e s i u m Activity (Bq/kg)
IIIB1986
I
11987 ~ 1 9 8 8
Fig. 2. Frequency histogram of the total radiocaesium activities of meat samples for 1986, 1987 and 1988.
the order of about 900 Bq/kg. In other types of meat, however, radiocaesium concentrations were always below 400Bq/kg (except for one sample of beef with 470 Bq/kg). It has been suggested that the reduction or decontamination of radionuclides in the food chain can be achieved by ion-exchange and
182
Lo(fi et al. TABLE 1
The Total Radiocaesium Activities of Meat Before and After Cooking Sample no.
258 B 294 A2 294 B2 219 B
Meat type
A B C D
Normalized radiocaesium content (uncooked = 100) Cooked
Water
Precipitation
Loss
21-5 20-4 16.1 26.2
30-0 29-6 25.6 27.1
27.7 22.6 28-8 36.3
20-8 27.1 29-5 10.1
electrodialysis techniques and/or washing, blanching and canning (Arnaud, 1988). An interesting observation is that radiocaesium in foodstuffs is reduced through cooking (Lotfi e t a l . , 1989, 1990). It has been found that, when a sample of meat is cooked in salt water (1%) for about an hour (a typical cooking time for most types of meat), the radiocaesium content decreases by as much as 80% relative to the uncooked sample. The results (Table 1) show that some 30% of the total radiocaesium content of the uncooked sample is released into the water in which the meat is cooked. No satisfactory explanation has been found for the unrecovered radiocaesium, though it has been suggested that high temperatures may cause losses of volatile radionuclides such as radiocaesium ( I A E A , 1989b).
ACKNOWLEDGEMENT One of the authors (M.L.) has carried out this work with the support of the ICTP Programme for Training and Research in Italian Laboratories, Trieste, Italy. REFERENCES Arnaud, M. J. (1988). The removal and/or reduction of radionuclides in the food chain. In Radionuclides in the Food Chain, ed. M. W. Carter. ILSI Monographs, Springer-Verlag, Berlin, pp. 195-213. Bujdoso, E. (1987). The Chernobyl reactor accident. A Current Bibliography, Part 1. J. Radioanal. & Nucl. Chem., Articles, 116(1), 223-31. Bujdoso, E. (1988). The Chernobyl reactor accident. A Current Bibliography, Part 2. J. Radioanal. & Nucl. Chem., Articles, 122(1), 215-24. Burkart, W. (1989). Radiation Protection. Survey of research and development activities initiated after the Chernobyl accident. Review Report, General
Radiocaesium contents of meat after the Chernobyl accident
183
Distribution, Nuclear Energy Agency (NEA), Organization for Economic Co-operation and Development (OECD), Paris, France. Carter, M. W. (ed.) (1988). Radionuclides in the Food Chain. Symposium on Radionuclides in the Food Chain, Vienna, Austria, 2-5 November 1987. ILSI Monographs, Springer-Verlag, Berlin, 518 pp. CEN (1988). Environmental Impact of Nuclear Accidents, Vol. 2, 4th Cadarache International Symposium on Radioecology, Cadarache, France, 14-18 March 1988. Section Documentation, Centre d'Energie Nucl6aire/Cadarache, 320 pp. ESNA (1988). 19th Annual Meeting of the European Society of Nuclear Methods in Agriculture, ESNA, 29 Aug.-2 Sept. 1988, Vienna, Austria, INIS-mf 11356, 238 pp. IAEA (1989a). International Symposium on Environmental Contamination Following a Major Nuclear Accident, 16-20 October 1989. International Atomic Energy Agency, Vienna, Austria, IAEA-SM-306. IAEA (1989b). Measurements of Radionuclides in Food and the Environment. A Guidebook. Technical Report Series No. 295. International Atomic Energy Agency, Vienna, Austria. Lotfi, M., Notaro, M., Azimi-Garakani, D., Piermattei, S. & Tommasino, L. (1989). Loss of radioactive caesium in cooked spaghetti. Sci. Total Environ., 79, 291-3. Lotfi, M., Notaro, M., Azimi-Garakani, D., Cubadda, R., Santaroni, G. P. & Tommasino, L. (1990). Concentrations of radiocaesium in Italian durum wheat and its products after the Chernobyl accident. J. Environ. Radioactivity, 11(2) 177-82. NEA (1987). The Radiological Impact of the Chernobyl Accident. Organization for Economic Co-operation and Development, Nuclear Energy Agency, Paris, France, 65 pp. Piesch, E. & Duftschmid, K. (eds) (1987). Chernobyl and the Consequences in Central Europe Seminar, Seibersdorf, Austria, Dec. 1986. Radiat. Prot. Dosim., 19(4), 207-56. UNSCEAR (1958). United Nations Scientific Committee on the Effects of Atomic Radiation. 1958 Report of the General Assembly, Annex D, United Nations, New York. YRPA (1987). Proceedings of the 14th Yugoslav Symposium on Radiation Protection, 8-11 June 1987, Novi Sad, Yugoslavia. Yugoslav Radiological Protection Association, Belgrade. Zifferero, M. (1988). A post-Chernobyl view. In Radionuclides in the Food Chain, ed. M. W. Carter. ILSI Monographs, Springer-Verlag, Berlin, pp. 1-9.
M. Lotfi,* M. Notaro, S. Piermattei, L. Tommasino & D. Azimi-Garakani* Directorate o f Nuclear Safety and Radioprotection (ENEA-DISP), Via Vitaliano Brancati, 48, 00144 Rome, Italy (Received 4 July 1989; revised version received26 September 1989; accepted 12 October 1989) *Present address: A~CC/SCN, X.50, World Health Organization, CH-1211 Geneva 27, Switzerland. *Present address: Paul Scherrer Institute, CH-5232 ViUigenPSI, Switzerland.
Technical Note Radiocaesium Contents of Meat in Italy After the Chernobyi Accident and Their Changes During the Cooking Process
ABSTRACT Levels of radioactive contamination in meat have been studied, along with ways of decreasing them. Specifically, radiocaesium concentrations in a range of samples of different types of meat collected throughout Italy since April 1986 are presented here. The samples are of beef, lamb, pork, chicken, turkey and rabbit. It was found that the radiocaesium content of lamb is higher than that in any of the other meat types considered here. Studies of the decrease in the radiocaesium content of meat during cooking showed that, when the meat is cooked in salt water (1%), the activity decreases by as much as 80% relative to uncooked samples.
INTRODUCTION The study of radionuclides in the food chain dates back some 30 years to the first report on the Effects of Atomic Radiation published in 1958 ( U N S C E A R , 1958). The early studies were mainly on the contamination of foodstuffs from fallout from atmospheric nuclear weapon tests. More recently, the nuclear accident at the Chernobyl Unit 4 reactor has provided a unique opportunity to study these processes on a large scale. The accident involved release of some 1018Bq of radionuclides of potential significance to the human food chain (Zifferero, 1988). During the past three years, hundreds of articles have been published on various aspects of this accident (Bujdoso, 1987, 1988). Many countries have established new radiation protection research programmes or have accelerated existing programmes (Burkart, 1989). In the process, considerable attention has been paid to food chain contamination 179 J. Environ. Radioactivity 0265-931X/90/$03.50 © 1990 Elsevier Science Publishers Ltd, England. Printed in Great Britain
180
Lotfi et al.
following this release of radionuclides to the environment (Piesch & Duftschmid, 1987; YRPA, 1987; Carter, 1988; CEN, 1988; ESNA, 1988). In the Italian adult diet, meat comprises on average about 14% of the consumption of main foodstuffs, the others being milk and milk products (22%), green leafy vegetables (13%), bread and pasta (26%), fish (2%) and fruit (23%) (NEA, 1987). It is therefore important to determine the radioactivity concentrations in different types of meat in order to evaluate the effective dose equivalent (EDE) received through meat consumption. The total radiocaesium concentrations of different foodstuffs in Italy and the resultant individual EDE commitment using food basket studies have been reported elsewhere (IAEA, 1989a). This paper describes the results of measurements of the radiocaesium concentrations in several samples of meat collected from throughout Italy since April 1986. The reduction in radiocaesium content of the samples as a result of cooking has also been studied.
MATERIALS AND METHODS The measurements were carried out by gamma-spectrometry using 450 ml Marinelli beakers and 30% HPGe detectors with a detection limit of <1 Bq/kg. The samples were of beef, lamb, pork, chicken, turkey and rabbit. A total of 377 samples was analysed and the concentrations of both 134Cs and 137Cs were determined. Of these, some 175 samples were from 1986, 108 from 1987 and the remainder from 1988.
RESULTS AND DISCUSSION Figure 1 shows the frequency histogram of the total radiocaesium contents of all the meat samples measured. One-third of the samples had radiocaesium concentrations below the lower limit of detection (LLD) of 1 Bq/kg. The results show that 65% of the samples of radiocaesium content above the LLD have concentrations of less than 50 Bq/kg. Those with concentrations in the range 50 to 100 Bq/kg comprise about 15% of the total. The weighted mean of the radiocaesium concentrations of all the samples is about 75 Bq/kg. The trend in the frequency of total radiocaesium contents from 1986 to 1988 is shown in Fig. 2. Analysis of the results shows that the radiocaesium content of lamb is higher than those of the other types of meat considered here. The highest radiocaesium concentration, of 1960 Bq/kg, was observed in a sample of lamb, another two samples of this type of meat having concentrations of
Radiocaesium contents of meat after the Chernobyl accident
181
Frequency(%) 70~ 60
50 40 30 20 10 0
50
l oo 15o 2o0 2so ~
~
4o0 45o soo
9o0
2o0o
Total C a e s i u m Activity (Bq/kg) il
1986-s8
Fig. 1. Frequency histogram of the total radiocaesium activities of all meat samples.
Frequency(%) 100 , [
8o!
4060020 h
L
in I1~ l, =-~ ==J = ~
J
J -, m
so
loo
1so 200 2so
300 350 400 4so soo
900
2000
Total C a e s i u m Activity (Bq/kg)
IIIB1986
I
11987 ~ 1 9 8 8
Fig. 2. Frequency histogram of the total radiocaesium activities of meat samples for 1986, 1987 and 1988.
the order of about 900 Bq/kg. In other types of meat, however, radiocaesium concentrations were always below 400Bq/kg (except for one sample of beef with 470 Bq/kg). It has been suggested that the reduction or decontamination of radionuclides in the food chain can be achieved by ion-exchange and
182
Lo(fi et al. TABLE 1
The Total Radiocaesium Activities of Meat Before and After Cooking Sample no.
258 B 294 A2 294 B2 219 B
Meat type
A B C D
Normalized radiocaesium content (uncooked = 100) Cooked
Water
Precipitation
Loss
21-5 20-4 16.1 26.2
30-0 29-6 25.6 27.1
27.7 22.6 28-8 36.3
20-8 27.1 29-5 10.1
electrodialysis techniques and/or washing, blanching and canning (Arnaud, 1988). An interesting observation is that radiocaesium in foodstuffs is reduced through cooking (Lotfi e t a l . , 1989, 1990). It has been found that, when a sample of meat is cooked in salt water (1%) for about an hour (a typical cooking time for most types of meat), the radiocaesium content decreases by as much as 80% relative to the uncooked sample. The results (Table 1) show that some 30% of the total radiocaesium content of the uncooked sample is released into the water in which the meat is cooked. No satisfactory explanation has been found for the unrecovered radiocaesium, though it has been suggested that high temperatures may cause losses of volatile radionuclides such as radiocaesium ( I A E A , 1989b).
ACKNOWLEDGEMENT One of the authors (M.L.) has carried out this work with the support of the ICTP Programme for Training and Research in Italian Laboratories, Trieste, Italy. REFERENCES Arnaud, M. J. (1988). The removal and/or reduction of radionuclides in the food chain. In Radionuclides in the Food Chain, ed. M. W. Carter. ILSI Monographs, Springer-Verlag, Berlin, pp. 195-213. Bujdoso, E. (1987). The Chernobyl reactor accident. A Current Bibliography, Part 1. J. Radioanal. & Nucl. Chem., Articles, 116(1), 223-31. Bujdoso, E. (1988). The Chernobyl reactor accident. A Current Bibliography, Part 2. J. Radioanal. & Nucl. Chem., Articles, 122(1), 215-24. Burkart, W. (1989). Radiation Protection. Survey of research and development activities initiated after the Chernobyl accident. Review Report, General
Radiocaesium contents of meat after the Chernobyl accident
183
Distribution, Nuclear Energy Agency (NEA), Organization for Economic Co-operation and Development (OECD), Paris, France. Carter, M. W. (ed.) (1988). Radionuclides in the Food Chain. Symposium on Radionuclides in the Food Chain, Vienna, Austria, 2-5 November 1987. ILSI Monographs, Springer-Verlag, Berlin, 518 pp. CEN (1988). Environmental Impact of Nuclear Accidents, Vol. 2, 4th Cadarache International Symposium on Radioecology, Cadarache, France, 14-18 March 1988. Section Documentation, Centre d'Energie Nucl6aire/Cadarache, 320 pp. ESNA (1988). 19th Annual Meeting of the European Society of Nuclear Methods in Agriculture, ESNA, 29 Aug.-2 Sept. 1988, Vienna, Austria, INIS-mf 11356, 238 pp. IAEA (1989a). International Symposium on Environmental Contamination Following a Major Nuclear Accident, 16-20 October 1989. International Atomic Energy Agency, Vienna, Austria, IAEA-SM-306. IAEA (1989b). Measurements of Radionuclides in Food and the Environment. A Guidebook. Technical Report Series No. 295. International Atomic Energy Agency, Vienna, Austria. Lotfi, M., Notaro, M., Azimi-Garakani, D., Piermattei, S. & Tommasino, L. (1989). Loss of radioactive caesium in cooked spaghetti. Sci. Total Environ., 79, 291-3. Lotfi, M., Notaro, M., Azimi-Garakani, D., Cubadda, R., Santaroni, G. P. & Tommasino, L. (1990). Concentrations of radiocaesium in Italian durum wheat and its products after the Chernobyl accident. J. Environ. Radioactivity, 11(2) 177-82. NEA (1987). The Radiological Impact of the Chernobyl Accident. Organization for Economic Co-operation and Development, Nuclear Energy Agency, Paris, France, 65 pp. Piesch, E. & Duftschmid, K. (eds) (1987). Chernobyl and the Consequences in Central Europe Seminar, Seibersdorf, Austria, Dec. 1986. Radiat. Prot. Dosim., 19(4), 207-56. UNSCEAR (1958). United Nations Scientific Committee on the Effects of Atomic Radiation. 1958 Report of the General Assembly, Annex D, United Nations, New York. YRPA (1987). Proceedings of the 14th Yugoslav Symposium on Radiation Protection, 8-11 June 1987, Novi Sad, Yugoslavia. Yugoslav Radiological Protection Association, Belgrade. Zifferero, M. (1988). A post-Chernobyl view. In Radionuclides in the Food Chain, ed. M. W. Carter. ILSI Monographs, Springer-Verlag, Berlin, pp. 1-9.
M. Lotfi,* M. Notaro, S. Piermattei, L. Tommasino & D. Azimi-Garakani* Directorate o f Nuclear Safety and Radioprotection (ENEA-DISP), Via Vitaliano Brancati, 48, 00144 Rome, Italy (Received 4 July 1989; revised version received26 September 1989; accepted 12 October 1989) *Present address: A~CC/SCN, X.50, World Health Organization, CH-1211 Geneva 27, Switzerland. *Present address: Paul Scherrer Institute, CH-5232 ViUigenPSI, Switzerland.