Cesium 137 Contamination of Wild Boars

In the months following the deposition of radiocesium from the Chernobyl fallout, levels ranging from a few becquerels of Cesium 137 per kilogram to several thousand becquerels per kilogram were measured in wild boar meat in Germany.
In 2020, the range of Cs 137 contamination in wild boar is still as wide, and maximum levels in some regions are higher today than in 1986.
One phenomenon is of particular importance: the large differences in radiation levels in wild boar occur not only between different regions in Germany, but also in areas more highly contaminated by Chernobyl fallout.
For example, it is also possible to have 2020 samples of wild boar from the same hunting ground simultaneously below 100 Bq Cs 137 per kg but also of several thousand Bq/kg. In addition, large seasonal variations in contamination can also occur in an area.

Up to date overview in Germany

The effects of the Chernobyl accident are limited after more than 30 years in Germany. However, the authorities are still concerned about the radioactivity of wild boars and some species of mushrooms. From a radiobiological point of view, only cesium-137 is relevant today. Foodstuffs from agricultural areas largely exhibit radiocesium activities, which were also measured before the reactor accident. However, due to special transfer processes in forest ecosystems, elevated cesium-137 contamination occurs here in some biomedia.

Deer truffles accumulate the nuclide to a particular degree. And since wild boars are particularly fond of eating these mushrooms, this leads to increased caesium-137 radiation exposure in wild boars. However, since wild boar do not consume deer truffles in equal quantities throughout the year and the truffles also fructify differently depending on the season, the whole thing is very dynamic. Here you can find information and measured values on the Cs 137 contamination of deer truffles.

Research Project “Assessment of contamination levels of wild boar (Sus scrofa) in Germany“

Project duration: 01.10.2017 – 31.01.2021, researcher: umweltanalysen.com. On behalf: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). Data Source: doris.bfs.de/jspui/bitstream/urn:nbn:de:0221-2020100623424/3/BfS_2020_SCHR_66-20.pdf

Sus scrofa (wild boar) is the only animal species that, even 30 years after the Chernobyl fallout, still has significantly increased Cs-137 contamination in some areas of the Federal Republic of Germany. The variability of the Cs-137 measured values both within and between different populations is very large. Deer truffles are the main source of contamination. In this research project, the contamination situation of wild boars is to be evaluated over a period of 3 years using current data from 3 study areas (Bodenmais, Dahn and Zusmarshausen). The project is divided into 3 work packages (WP):

• – Collection of information on hunting range and shooting weights (WP1)
• – Sampling and measurement of deer truffles in the study areas (WP2)
• – Sampling and measurements on muscle meat samples from wild boars (WP3).

Implementation WP3

 Wild boar – sample processing and Cs-137 activity determination

The 3 forestry departments were provided with packaging material for the dispatch of the wild boar muscle flesh samples. The following data were recorded for each wild boar hunted: forest office, hunt date, hunted class, sex, type of hunt and hunt weight [kg]. The thawed muscle meat was homogenized and weighed into 120 ml measuring vessels. The samples were measured on pure germanium detectors. The measurement times were 6 to 24 hours, depending on the activity of the sample.

Results

From September 1st, 2017 to December 31st, 2019, muscle meat samples from 376 wild boars were delivered by the forest services (Bodenmais 129, Dahn 123 and Zusmarshausen 124). So far, 355 samples have been measured for Cs-137 activity. The Cs-137 contamination of wild boars fluctuated seasonally depending on the availability of individual food components within a study area, with the variability of the measured values being up to three orders of magnitude. The values ranged from 0.6 Bq/kg fresh mass (FM) (Dahn) to 16,704 Bq/kg (Bodenmais). The median of the measured values of 2,857 Bq/kg in Bodenmais shows the significantly higher Cs-137 contamination of the wild boar population compared to Dahn with 7.5 Bq/kg and Zusmarshausen with 118 Bq/kg. In the mast years, wild boars were significantly less contaminated than in the years without large amounts of fruits of beech and oak.

 

Cesium 137 readings 2020

Radioactive measurements on meat samples of wild boar from Bavaria are carried out by the Bavarian State Office for the Environment and Food Safety, among others. For 2020, the following results are published on the website of the LfU (Table 1). With regard to the measured Cs 137 activities, it should be noted that it is predominantly meat from animals that have been officially placed on the market. Accordingly, the values are below the 600 Bq limit. In southern Germany, regionally significantly higher caesium contamination levels are measured in wild boar, in some cases up to 10,000 Bq/kg. These animals are not traded, they are disposed of.

Radioactivity measurements at the laboratory for radioisotopes at the University of Göttingen

Since April 1986 the author has investigated the radioactive contamination of wild animals in various research projects. Unless otherwise indicated, all measurements for radioactivity were carried out in the Laboratory for Radioisotopes at the University of Göttingen. The LARI has a non-nuclide-specific handling permit and can therefore measure radioactive substances within the limit values of activity class SK2.

Wild boar cesium 137 contamination in 1986

In the following table measured values of radiocesium activity of wild boars from Germany from 1986 to 1987 are given. The data were collected at the former Institute for Wildlife Biology and Hunting Science at the University of Göttingen. The measurements were made at the former Isotope Laboratory of the University of Göttingen (now the Laboratory for Radioisotopes). Measured values in fresh weight (FW).

Date of shooting	Place of shooting	Cs-134	Cs-137
		[Bq/kg FW]	[Bq/kg FW]
04.06.1986	Hannoversch Münden	56	120
07.06.1986	Fintel	42	84
12.06.1986	Hammelburg	12	25
18.06.1986	Nörten Hardenberg	61	131
22.06.1986	Prezelle	249	526
25.06.1986	Wriedel	23	65
29.06.1986	Gleichen	15	29
01.07.1986	Bad Lauterberg	179	381
02.07.1986	Hannoversch Münden	100	194
02.07.1986	Hannoversch Münden	86	188
03.07.1986	Weil	42	83
08.07.1986	Gleichen	35	66
09.07.1986	Hannoversch Münden	49	103
09.07.1986	Hannoversch Münden	55	103
11.07.1986	Hannoversch Münden	100	194
12.07.1986	Bad Soden-Allendorf	25	44
14.07.1986	Rosdorf	64	134
14.07.1986	Hofgeismar	112	237
14.07.1986	Detmold	116	237
16.07.1986	Hannoversch Münden	116	189
16.07.1986	Hannoversch Münden	116	189
21.07.1986	Bühren	31	52
06.08.1986	Kehlheim	19	79
14.09.1986	Saumslek	30	64
20.09.1986	Gleichen	12	26
23.09.1986	Bargteheide	6	14
24.09.1986	Hardegsen	17	55
27.10.1986	Einbeck	29	64
16.11.1986	Reinhardshagen	90	216
16.11.1986	Reinhardshagen	92	237
16.11.1986	Reinhardshagen	91	221
16.11.1986	Reinhardshagen	142	343
16.11.1986	Reinhardshagen	89	225
16.11.1986	Reinhardshagen	103	271
14.12.1986	Nörten Hardenberg	5	10
15.12.1986	Springe	29	69
15.12.1986	Springe	16	41
15.12.1986	Springe	34	77
15.12.1986	Springe	42	104
15.12.1986	Springe	28	77
15.12.1986	Springe	16	37
15.12.1986	Springe	28	70
15.12.1986	Springe	19	44
15.12.1986	Springe	15	32
27.01.1987	Dassel	58	154
27.01.1987	Dassel	42	99
22.06.1987	Friedland	4	18
24.06.1987	Rosdorf	26	59
24.06.1987	Rosdorf	15	29
17.08.1987	Bodenmais	1.062	3619
26.08.1987	Gleichen	0	10
01.10.1987	Bodenmais	925	3020
04.10.1987	Bodenmais	982	4602
08.10.1987	Bodenmais	839	2699
31.10.1987	Kelheim	4	22
22.11.1987	Bodenmais	1455	5425
03.12.1987	Gartow	17	56
10.12.1987	Kassel	13	58
11.12.1987	Bodenmais	278	973
06.01.1988	Gartow	12	43
11.02.1988	Gartow	8	29
23.03.1988	Gartow	1	6
06.07.1988	Bodenmais	590	2284
15.07.1988	Bodenmais	408	1668
29.07.1988	Fuhrberg	5	26
21.08.1988	Fuhrberg	4	27
26.08.1988	Fuhrberg	2	8
29.08.1988	Fuhrberg	8	40
28.09.1988	Fuhrberg	24	118
28.09.1988	Fuhrberg	7	33
11.10.1988	Fuhrberg	16	85
26.10.1988	Fuhrberg	11	53
30.10.1988	Fuhrberg	6	33
08.11.1988	Bodenmais	306	1306
18.11.1988	Fuhrberg	25	134
19.11.1988	Bodenmais	143	653
21.11.1988	Fuhrberg	5	22
22.11.1988	Fuhrberg	6	34
22.11.1988	Fuhrberg	4	21
22.11.1988	Fuhrberg	9	53
23.11.1988	Fuhrberg	5	22
23.11.1988	Fuhrberg	5	26
30.01.1989	Fuhrberg	26	138
30.01.1989	Fuhrberg	5	29
30.01.1989	Fuhrberg	5	30
09.05.1989	Bodenmais	6	30
09.05.1989	Bodenmais	6	32
18.05.1989	Bodenmais	470	2433
31.05.1989	Bodenmais	316	1762
16.07.1989	Bodenmais	410	2046
31.10.1989	Bodenmais	781	4991
07.12.1989	Bodenmais	384	2469
07.12.1989	Bodenmais	251	1762

Wild boar Cs 137 contamination in Japan – Fukushima accident

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011 released large amounts of man-made radioactive substances into the environment. In a study of radiocesium levels in wild boars in Japan, Cui et. al (2020) measured the concentration of Radiocesium (Cs 134 + Cs 137) in 213 muscle samples from wild boar (Sus scrofa) caught in the town of Tomioka, which is 20 km from the FDNPP. The results show that 210 (98.6%) muscle samples still exceed the regulatory Radiocesium limit (100 Bq/kg) for general foods. Radiocesium values (Cs 134 + Cs 137) were between 87.1 and 8,120 Bq/kg fresh mass (FM) with a mean concentration of 450 Bq/kg FM. The distribution of the radiocesium activity is shown in Figure 3.

Literature

Agentur für Gesundheit und Ernährungssicherheit: Cäsium 137-Belastung von Wildfleisch in Österreich

Cui, L., Orita, M., Taira, Y., Takamura, N., 2020: Radiocesium concentrations in wild boars captured within 20 km of the Fukushima Daiichi Nuclear Power Plant. Sci Rep 10, 9272 (2020). https://doi.org/10.1038/s41598-020-66362-6. Link zur Quelle

Fielitz U., 2005: Untersuchungen zum Verhalten von Radiocäsium in Wildschweinen und anderen Biomedien des Waldes

Fielitz U., 1996: Radiocäsium in Wildtieren nach dem Reaktorunfall von Tschernobyl

Hartmann, P., Urso, L., Fielitz, U., Steiner, M., 2016. A probabilistic/stochastic model for contamination levels of Cs-137 in Wild Boars. In: IRPA conference. Cape Town. 9-13 May 2016.

Rachubik J., 2008: Radiocesium in Polish game meat

Radioactive wild boars in Sweden are eating nuclear mushrooms

Tataruch F., Schönhofer F., Onderscheka K., 1988: Untersuchungen zur radioaktiven Belastung der Wildtiere in Österreich