Factors Affecting Radionuclide Availability to Vegetables Grown at Los Alamos

Abstract

AbstractA field study was conducted in 1977 on 238, 239Pu and 137Cs availability to zucchini squash (Curcurbita melopepo, hybrid seneca) and green bush beans (Phaseolus vulgaris, Landreths stringless) grown under home‐garden conditions in an area at Los Alamos National Laboratory used for treated radioactive liquid waste disposal. Radionuclide concentrations were measured as a function of tissue type, height above the soil, fertilization regime, and for the squash, food‐cleansing procedures. Analysis of variance procedures were used to analyze the data.Ratios of the concentration of a radionuclide in oven‐dried vegetation to dry soil ranged from 0.0004 to 0.116 for the Pu isotopes, and from 0.051 to 0.255 for 137Cs. Fertilization with cattle manure reduced the Pu concentration ratios by 30% and 137Cs by 50%. Vegetative parts sampled within 20 cm of the ground surface were contaminated about four times as much as those parts growing further from the ground surface. About 65% of the contamination was removed by washing, indicating the presence of surficial contamination. The 50‐year radiation dose commitment to humans consuming vegetables from the garden plot would be less than 0.05 mrem and would be due almost entirely to 137Cs.