V. R. Bohman

Fallout Concentrations in Cattle Grazing Highly Contaminated Range

In 1958 a herd of beef cattle was moved to graze the desert range over which atmospheric nuclear weapons tests had just concluded. In 1962 the same herd of beef cattle was exposed to a contaminated range following an underground detonation (Bandicoot) about three months after grazing range contaminated by the “Sedan” cratering nuclear detonation. The observed data are qualitatively consistent with the known contamination of the test herd grazing range on the Nevada Test Site of the U.S. Atomic Energy Commission, and the physical half-life and metabolic rate constants of the radionuclides studied. Thyroid 1311 rose to very high concentrations when cattle grazed freshly contaminated range and then dropped very promptly. ‘The degree of contamination with radioiodine was such that 1311 was easily measurable in soft tissues. The thyroid 1311 Concentrations were about 1000 times that of soft tissues with the blood concentration being greater than liver and muscle. Cesium-1 37 concentrations started from a higher pre-exposure level due to its long half-life, increased in response to grazing contaminated range and decreases when cattle are returned to normal ranges. Strontium-90 tissue concentrations increased when cattle grazed contaminated range and then decreased ‘The observed concentrations of radioiodine in the thyroid glands indicated approximately the same degree of contamination with radioiodine by the two experiments. Much greater increases in radiostrontium and radiocesium concentrations occurred following the 1962 experiment. This is interpreted to indicate greater uptake of these long-lived isotopes resulting primarily from the “Sedan” cratering experiment than from the accidental release of fission products from the “Bandicoot” experiment. In each experiment the cattle received an estimated 80 rad to the thyroid gland. slowly.

Bovine Thyroid Iodine-131 Concentrations Subsequent to Soviet Nuclear Weapon Tests

The iodine-131 concentration in thyroids of cattle slaughtered in Reno, Nevada, was measured during and following recent atmospheric nuclear weapon tests by the U.S.S.R. The iodine-131 concentration rose rapidly to a maximum and then declined with an apparent half-life of 7 days after conclusion of the test series. The average dose to bovine thyroids from this test series was estimated to be 17 rads.

Cesium-137 from environmental sources in desert range cattle from 1962 through 1968

Abstract Following the cessation of atmospheric nuclear weapons testing in late 1962, cesium-137 concentrations in desert range cattle continued to increase for a year and then decreased following the trend in world-wide fallout. On the Nevada Test Site of the U. S. Atomic Energy Commission, range cattle soft-tissue concentrations of 147Cs reached a maximum earlier, indicating response to local contamination. Tissue 137Cs concentrations did not respond to small, isolated releases of fission products from underground testing. The levels of 137Cs observed were comparable with those found in meat elsewhere in the northern hemisphere.

Fallout 131I in Western Nevada cattle thyroid glands : 1962-early 1969

There has been continuing interest in historical fallout data. The authors have previously published data concerning the concentrations of fallout radioactive {sup 131}I in the thyroid glands of cattle from the Nevada Test Site and from commercial slaughter cattle. These data showed that bovine thyroid {sup 131}I was an effective monitor of both local and worldwide fresh nuclear fallout. This paper extends the data on commercial slaughter cattle from western Nevada through early 1969.