Seasonal variations in the transfer of 137Cs and 40K to pasture grass and its ingestion by grazing animals.
Samples of grass and sheep faeces were taken monthly over a 12-month period from three pasture sites. Biomass, 137Cs and 40K were measured. The activity concentration of these two radionuclides in grass was influenced by season and soil type. The seasonal patterns of 137Cs and 40K transfer to grass were inversely related, but evidence is presented which suggests that soil contamination of grass samples contributed to the 137Cs and 40K activity concentrations of the grass and augmented the difference between their patterns of transfer. This was influenced by season, climate and farm management. A parallel seasonality was identified in the 137Cs activity concentration of the faeces of sheep grazing these pastures. This was not observed for 40K in sheep faeces.
Radiological Protection Institute of Ireland, Dublin.
B
B
Rafferty
D E
DE
Dawson
P A
PA
Colgan
D000818:Animals; D002588:Cesium Radioisotopes / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D005243:Feces / Q000737:chemistry; D005506:Food Contamination / Q000032:analysis*; D006109:Poaceae / Q000737:chemistry* / Q000378:metabolism; D011197:Potassium Radioisotopes / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D012621:Seasons; D012756:Sheep / Q000378:metabolism*; D012989:Soil Pollutants / Q000032:analysis / Q000493:pharmacokinetics*
D002588:Cesium Radioisotopes; D011197:Potassium Radioisotopes; D012989:Soil Pollutants