Cl-36 transfer to ryegrass and consequences for environmental modeling

Department of Nuclear Engineering & Radiation Health Physics, Oregon State University, Corvallis, OR 97331, USA

Abstract

There has been recent interest in the transport and fate of 36Cl in the environment. The IUR task force on Radioecology and Waste has identified the need for further uptake data. Reported here are the results of a 6-month study of the uptake in ryegrass of 36Cl in five lysimeters. Lysimeters were deployed in a greenhouse from November 2007 to May 2008. Except for an initial watering, exterior reservoirs connected to the base of the lysimeters maintained the water tables at a constant level with a solution containing 36Cl in a chloride form. A destructive analysis of the lysimeters showed that between 75 and 80% of 36Cl added to the system during the course of the experiments was taken up into the plant tissue. The quantities of 36Cl found in weekly soil tests and a simple mass balance provide supporting evidence for the significant bioavailability of 36Cl in a chloride form.