Parameters for Modelling the Interception and Retention of Deposits from Atmosphere by Grain and Leafy Vegetables

Publisher Website
Google Scholar
Abstract
The normalized specific activity (NSA), a quantity which relates the concentration of a contaminant per unit mass of vegetation to its daily rate of ground deposition, was used as the basis for determining interception factors and retention half-lives for radioactive contaminants deposited on grain and leafy vegetables. The values were for use in assessing contamination levels on crops at harvest during conditions of continuous deposition. The approach implicitly took account of other processes which inflenced foliar contamination, namely, translocation and dilution due to plant growth. The respective NSA values for grain and prepared leafy vegetables determined from several experimental studies were fairly constant and were of about the same level for fallout Sr and Cs. There was evidence from previous studies on herbage to suggest that similar NSA values might be expected for other contaminants on grain and leafy vegetables. Pu was an exception in that NSA values for grain and prepared leafy vegetables were lower than those for the fission products by factors of 5-10 depending upon the source of the contaminant. Consideration was given to determining the most appropriate value of the fraction of activity transferred from grain to flour during refining. This was an element dependent parameter and the values estimated for Sr, Cs and Pu were respectively, 0.15, 0.5 and 0.1. The study indicated the need for data in several areas in order to improve the capability to model interception and retention on field crops in continuous and acute release conditions.

This publication has 0 references indexed in Scilit: