Animal cesium concentration

To date, no sign of essentiality for plants, animals, and humans have been reported for cesium neither has any biomagnification by fauna been described, and soil concentrations of cesium are always much higher than that of both plants and animals. Cesium bioconcentration has not been observed in any specialized parts of plants, except for the skin of the hats of certain types of mushrooms, wherein cesium (detected as radiocesium) accumulates to high levels. In this situation it is thought that the cesium is enriched in the color pigments of the hat skin (Kalac, 2001). The potassium content of the mushroom was also found to relate inversely to the cesium content in other words, the higher the potassium content, the lower the cesium content (Marin et al., 1997). 

The half-period for decrease of muscle cesium-137 concentration in NTS animals after the cessation of atmospheric nuclear weapons testing in 1959 appears anomalous (Table I and Figure 2). In addition to being considerably greater (2.3 years) than the other half-periods found, its standard deviation was larger than the value. If one considers only the initial rate of decrease of radiocesium in these muscle samples, one finds a half-period of 0.9 year which is quite consistent with other data. Examination of these data, in comparison with data from liver (Figures 2 and 3), indicates that only muscle decreased its rate of decline in 1960. It should also be noted that the values during 1960 were only about twice the standard error of analysis. Thus, analytical error alone is not an improbable cause of these anomalous values. 

The synthesis of pazopanib (1) involves sequential animation of 2,4-dichloropyrimidine 25 with 6-amino-2,3-dimethylindazole 24 and 5-amino-2-methyl-benzenesulfonamide 28. The 6-amino-2,3-dimethylindazole 24, on the other hand, was prepared from 2-ethylphenylamine 20 via 5-nitration with fuming nitric acid and concentrated sulfuric acid, followed by treatment with isoamyl nitrite and acetic acid to produce 6-nitro-3-methylindazole 22. The 6-nitro group was reduced with stannous chloride and concentrated HC1 in glyme and subsequently methylated at the C2 position of the indazole ring with trimethyloxonium tetrafluoroborate in acetone to produce 6-amino-2,3-dimethylindazole 24. The resultant indazole 24 was condensed with 2,4-dichloropyrimidine 25 in the presence of sodium bicarbonate in ethanol/THF and subsequent iV-methylation with iodomethane and cesium carbonate to produce 27. The 2-chloro group of pyrimidine was then allowed to react with 5-amino-2-methyl-benzenesulfonamide 28 in catalytic HCl/isopropanol and heated to reflux to deliver pazopanib hydrochloride (1) in good yield. 

The metabolism and tissue distribution of cesium-137 were studied in rats injected intraperitoneally and sacrificed 1-300 days postinjection. In a chronic study, rats were administered cesium-137 in their drinking water daily. In the acute study, with the exception of the brain, muscle, and total animal, all tissues showed retention curves resolvable into three exponential components with half-lives of 1.5-2, 5-8, and 15-17 days. Retention in muscles was resolvable into a two-exponential function with half-lives of 8 and 16 days. In the chronic study, the highest equilibrium cesium-137 concentrations, 10% of the average daily intake per gram, occurred in the muscle. The authors concluded that the muscle should be considered the formal critical organ for cesium-137. 

Terrestrial animals acquire radionuclides through ingestion of food and water (and soil, in some cases), inhalation of air, and sorption through the epidermis (skin). Radionuclides that are analogues of stable nutrients (e.g., 14c " °K) are most easily metabolized in food and water. Rarer radionuclides, such as isotopes of plutonium and americium, are about four orders of magnitude less easily absorbed from food. Amphibians are often more sensitive to epidermal sorption because of their porous epidermis and immersion in potentially contaminated aquatic environments. Fish are also immersed in their environments so that concentrations of mai r radionuclides in their bodies are about 10-100 Bq kg of wet flesh for every Bq of water (carbon, phosphorus, and cesium are notable exceptions). 

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