At the beginning of the spring, as has happened every year since 2000, fresh seeds will be sown in open field plots located near to the reactor in Chernobyl, in an area that was seriously affected by radioactive fallout after the accident. Planting these crops is part of an experimental programme developed by the IRSN's Radioecology and Ecotoxicology Laboratory (LRE) in partnership with the Ukrainian Institute of Agricultural Radiology in Kiev and which is scheduled to continue until 2007. The objective is, firstly, to collect the basic data required to assess what happens to radionuclides that persist in the environment following accidental contamination and to model their transfer down the food chain. Secondly, the researchers are studying the behaviour of certain long-lived radionuclides in agricultural land ecosystems.
In practice, different crops representing the main categories of plants grown for human consumption, such as cereals (wheat), root vegetables (potatoes and radishes), leafy vegetables (lettuce) and fruit vegetables (beans and peas) are grown on four 4mx4m square plots. Each plot contains a different type of soil selected on the basis of its organic matter content and its pH value, important factors that affect the behaviour in the soil of the radionuclides studied. Two types of soil low in humus, one acidic and the other basic, together with two types of soil rich in organic matter were chosen. All four plots were subject to the same level of contamination up to a depth of 20 cm with one or more of the radionuclides studied as part of this programme: 36Cl, 129I, 239-240Pu, 241Am and 99Tc. In fact, it is not the residual contamination from the accident that is being studied, but contamination under controlled conditions.
In addition to these studies on transfer through the food chain, research at this experimental site also covers the movement and bioavailability of the radionuclides in soil: this involves assessing their vertical migration, and monitoring their concentration in the soil solution by taking samples each month throughout the year following contamination of the soil, and then every four months in subsequent years.
Colle C., Kashparov V. (2004). Fate of long-lived radioactive halogens, (36Cl, 129I), in agricultural ecosystems and human food chains : experiments and field investigations. International Congress ECORAD 2004, Aix-en-Provence (France), September 2004.
Kashparov V., Colle C., Zvarich S., Yoschenko V., Levchuk S. and Lundin S., 2005. Soil-to-plant halogens transfer studies 1. Root uptake of radioiodine by plants
, J. Env. Radioactivity 79, 187-204
Kashparov V., Colle C., Zvarich S., Yoschenko V., Levchuk S. and Lundin S., 2005. Soil-to-plant halogens transfer studies 2. Root uptake of radiochlorine by plants, J. Env. Radioactivity 79, 233-253.