Some aspects of obtaining the radiologically safe vegetable products in the conditions of Ukrainian Polissia

Abstract

Considering the urgent need for rehabilitation ofthe Chоrnobyl-affected agricultural lands of Ukrainian Polissia and maximization of the restoration of agricultural production in this area, the issue of reorganization of vegetable growing as one of the most radioecologically problematic in the region deserves to be specially highlighted. The study aimed to determine the influence of species and varietal characteristics, as well as soil, fertilizers, and irrigation on the accumulation of 137Cs by vegetable crops in the remote period after the Chornobyl accident. The research was conducted during 2008–2012 in the II, III, and former IV radioactive contamination zones on the territory of Chernihiv, Kyiv, and Zhytomyr regions. The soil cover of the studied area is represented by sod-podzolic sandy and peat-swamp soils. The most common for the region and recognized species and varieties of vegetables were studied, the list of which was determined by a questionnaire: cucumber; zucchini; pumpkin; scallop; red beet; garden carrot; red cabbage; Savoy cabbage; white cabbage, potatoes of different maturity groups, parsley. Soil and plant samples were taken during the industrial ripeness and the flowering (for potatoes) phases of vegetables. To study the effect of elevated doses ofmineral fertilizers and moldon the value of the 137Cstransfer factor from soil to potato tubers, a complex of mineral fertilizers was used: ammonium nitrate (34% N), tagged superphosphate (19% P2O5), potassium sulfate (50% K2SO4) and hummus made from hog manure. Acceptable levels of soil contamination with 137Cs were calculated by the formula based on the transfer factors and the effectiveness of agricultural measures conducted. The peculiarities of 137Cs accumulation in vegetable products depending on the species, variety, soil, fertilizer, and irrigation have been analyzed and the corresponding acceptable levels of soil radioactive contamination have been determined. The most severe restrictions to vegetable production in radioactively contaminated areas have been set forleaf vegetables, as well as for growing on peat-swamp soils. It has been confirmed that the greatest reduction in the 137Cs intake by vegetables is achieved by irrigation with fossil groundwater. The research findings make it possible to calculate the maximum acceptable levels of 137Cs soil contamination for growing different recognized varieties of vegetables under different fertilizer combinations and irrigation for a certain soil type. Guidelines for vegetable production on radioactively contaminated soils have been proposed, taking into account the varietal characteristics of the crop, fertilizer, and irrigation.