After the Fukushima Daiichi nuclear disaster released enormous amounts of radiation into the environment, scientists and researchers in Japan began monitoring the concentration of Cesium-134 and Cesium-137 in the organs of 79 abandoned cattle within a 20 kilometer radius of the nuclear power plant.
Over 3,000 cows, 30,000 pigs, and 625,000 chickens were left behind in the 20 kilometer area after the disaster. On May 12th, 2011, the Japanese government ordered Fukushima Prefecture to euthanize the cattle in the evacuation zone, but this was not strictly followed.
Between August 29th and November 15th, 2011, the team collected 79 cattle from Minami-Soma city and Kawauchi village, 63 of which were adult females, 3 of which were pregnant, 10 male calves and 3 female calves.
All of the samples tested were positive for Cs-134 and Cs-137. Ag-110m (radioactive silver) was found in the livers of all of the animals except for fetuses and Te-129m was also found in their kidneys despite the relatively short half-life of 33.6 days. Radioactive Ag-110m is not a fission product but is formed by the neutron capture of stable Ag-109. From this data the scientists were able to compare cumulative data and conclude that the liver is the primary target organ for Ag-110m deposition, while the kidney is the target organ of Te-129m deposition.
The transfer of radionuclides from mother to fetus is one of the major concerns of exposure to internal radiation, especially when concern Cesium, which is considered to transfer freely between the mother and the fetus, and is assumed to be uniformly distributed throughout all of the tissues of the fetus. The levels of radioactive cesium in the organs of fetuses and infants were found to be between 1.2 and 1.5 times higher than that of the maternal organs, indicating that the radiocesium is more concentrated in the fetus than the mother.
Source: PLOS One