PULVERDAMPF

Radiocaesium released after the Chernobyl nuclear power plant accident in April 1986 caused a total ground contamination of the southern states of Germany (Bayern, Baden-Württemberg, Reinland-Pfalz) roughly between 10 000 and 100 000 Bq m−2. In semi-natural ecosystems, especially forest ecosystems, radiocaesium is longer persistent as compared to agricultural areas due to differences in soil characteristics. Forest soils often have a thick humus layer which binds the radiocaesium reversibly keeping it available to plants and mushrooms, and at the same time hindering it in migrating downwards into the soil. Consequently, high activities of the radionuclide are observed in components of forest ecosystem such as mushrooms, plants, berries, and wild animals (Zibold et al., 2001).

Pröhl et al. (2006) reported that in forest ecosystems of Germany and Austria radiocaesium contamination of game meat, plants and mushrooms decreased with ecological half-lives of about 5–12 years, showing some variability apparently due to differences in soil type and climate. The concentration of 137Cs in different components of a forest ecosystem depends on the level of area contamination, radionuclide bioavailability and on the individual abilities of species to accumulate 137Cs. Therefore, wild animals inhabiting the same forest have very different levels of 137Cs meat contamination. For instance, in several federal states of Germany as Bavaria ( [Fielitz, 2005], [Fielitz et al., 2009], [Hecht, 2001] and [Steiner and Fielitz, 2008]), Rheinland-Pfalz (Hohmann and Huckschlag, 2005), and Baden-Württemberg (Zibold et al., 2001), and, additionally, in Austrian forests (Strebl and Tataruch, 2007) the 137Cs activity concentration in red deer (Cervus elaphus) and roe deer (Capreolus capreolus), except for the mushroom season in autumn, is rather low and continuously decreasing with time, whereas the contamination of wild boar (Sus scrofa) is remaining on a rather high level and exhibits a much slower decrease or is even constant over time. This could be explained by the differences in habitat and dietary habits of these animals. Roe deer normally is restricted to a relatively small habitat territory and feeds mostly on less contaminated herbal plants, apart from the mushroom season, while wild boar belongs to omnivores accepting a variety of food and is capable to move over long distances.

Among the factors influencing the contamination of the wild boar meat different authors named the radiocaesium inventory, season, fodder availability, habitat area location (woodland only or access to field crops), and the animal weight ( [Fielitz, 2005], [Hecht, 2001], [Hohmann and Huckschlag, 2005] and [Vilic et al., 2005]).

In the Bavarian Forest with a mean 137Cs inventory of 54 000 Bq m−2 and peak values exceeding 100 000 Bq m−2 the activity levels in the wild boar meat ranged between 80 and 40 000 Bq kg−1 in 2004 (Steiner and Fielitz, 2008). The dose conversion factor for ingestion of 137Cs (age of the consumer > 12 years) is 1.3 × 10−8 Sv Bq−1 (IAEA, 1996). On the contrary, for Croatia with lower 137Cs inventories of up to 20 000 Bq m−2 it was shown that the activity concentration in meat during 2000–2002 varied between 0.4 and 611.5 Bq kg−1 (Vilic et al., 2005). Roe deer with access to agricultural land have been found to be less contaminated than those living inside forests (Kiefer et al., 1996); the same is expected for wild boars.

Wild boars, non-specialised feeders (omnivores), are able to adapt their diet to locally and seasonally varying conditions. After the analysis of 40 wild boar stomachs collected between May 2002 and June 2003 in the Bavarian Forest, Steiner and Fielitz (2008) deduced that on average green forest plants, supplementary feed, soil and deer truffle contributed to about 56%, 24%, 11% and 6% of the stomach content, respectively. They also noticed that the diet composition changed completely in the second half of the year due to mast events when beechnuts became the dominating food component during September 2003 to February 2004.

Changes of the dietary habits of the wild boar during different seasons due to the fodder availability are considered to be the dominant factors influencing the level of 137Cs contamination of meat (Hecht, 2001). As it was demonstrated in several studies in different areas of Southern Germany ( [Fielitz, 2005], [Hecht, 2001] and [Hohmann and Huckschlag, 2005]), the 137Cs concentration in meat of wild boars appeared to be higher between January and April and started to decrease in May to July, reaching its minimum in October to December. The ingestion of fungi, in particular of deer truffles (Elaphomyces granulatus) with fruit bodies available throughout the year, was considered to be the main source for high radiocaesium concentration in wild boars ( [Fielitz, 2005], [Hohmann and Huckschlag, 2005], [Putyrskaya et al., 2003] and [Steiner and Fielitz, 2008]). Deer truffles are able to accumulate 137Cs effectively. Putyrskaya et al. (2003) showed that the aggregated soil-plant transfer factor Tag for deer truffles collected in the district Ravensburg was about 0.6 m2 kg−1 (fw), which is larger (up to two orders of magnitude) than for other fungi and forest plants. Fielitz (2005) reported that in the Bavarian Forest deer truffles contained extremely high levels of radiocaesium varying from 5000 to 122 000 Bq kg−1 (fw), which is in average a factor of up to 1000 higher as compared to other feeds like beechnuts, plants, and berries.

Hohmann and Huckschlag (2005) found no correlation between wild boar meat contamination and the total weight of the animal; however, individual wild boars with a weight of less than 10 kg were often higher contaminated than animals with larger weight. Hecht (2001) showed that the activity concentration of radiocaesium in muscle tissue of young roe deer was higher than for older animals as young roe deer have higher fodder consumption in relation to the total animal weight.

Over twenty years after the Chernobyl accident, 137Cs activity concentration in muscle meat of individual wild boar in the district Ravensburg was often exceeding several thousand Bq kg−1 and remained constant on a rather high level during the last decade. The variability of 137Cs activity concentration in wild boar meat in this region was rather large; the activity concentration of 137Cs varied over three orders of magnitude. A seasonal pattern in the 137Cs contamination level was observed within each studied year (except for mast years), in agreement with other studies. Large values were observed during January to March, low values between September and November. A correlation between the 137Cs meat contamination and the number of days with a closed snow cover and also with the number of ice days was found. This correlation could be explained by the consumption of deer truffles during periods when no green fodder was available for animals. Consumption of mast fruits (beechnuts and acorns) was responsible for suppressing the maxima in 137Cs activity concentration during the winter which followed a mast season. The aggregated transfer factor soil – wild boar, Tag, varied between 0.008 and 0.062 m2 kg−1 in the district Ravensburg in agreement with Tag of other European forests.

Due to the fact that in forest soils 137Cs remains essentially in the top 10–15 cm, where the organic soil and also hyphae and fruit bodies of deer truffles are located, the wild boar meat contamination is expected to decrease only very slowly with a time scale of decades.

Barry08 hat geschrieben:Lieber dodl!

Die Wuidsau is voll gefährlich!
Bring sie mir vorbei, ich opfere mich,
zumal ich in der kritischen Zeit damals wiederholt in Kiev
und anderen Städten der Ukraine unterwegs war.
Bei mir ist es also schon Wurscht...


Trichinenbeschau finde ich wichtiger....

WH vom
Barry

cobaltbomb hat geschrieben:Edit:
habe auf der karte vom bundesministerium nachgesehen. im waldviertel war wenig niederschlag im zeitraum der wolke
die gemessene straghlung war auch nicht hoch im vergleich zum rest Ö
ich denke du kannst es essen
....