Estimation of grass to milk transfer coefficient for cesium for emergency situations

Abstract

The grass to milk transfer coefficient is usually represented as F m values. This paper reports the results of grass to cow milk transfer coefficients (F m ) for Cesium for emergency situation. An experimental grass field was developed in Kaiga region and two cows were adopted for collecting milk samples regularly. Grass was cut from the field and spiked with very low concentration of Cs (in the form of CsCl or CsI), to simulate a sudden deposition of Cs on grass and fed to the adopted cows. The milk samples were collected during normal milking periods (morning and evening) for several days and analyzed. The peak concentration of Cs in milk was observed during time period 24-36 hrs after the intake of spiked grass. Three spike experiments were carried out and values of F m were found to be 7.8 × 10 -3 d L -1 , 3.5×10 -3 d L -1 and 2.4×10 -3 d L -1 . The grass to milk transfer coefficient values observed under spiked conditions were an order of magnitude lower when compared to the equilibrium transfer coefficient for Kaiga region, which highlights the importance of studies aimed at generating site-specific database on F m for simulated emergency situation.