The Soviet and, later, Commonwealth of Independent States (CIS) authorities introduced a wide range of short and long term environmental countermeasures to mitigate the accidents negative consequences. The countermeasures involved huge human, financial and scientific resources.
Decontamination of settlements in contaminated regions of the USSR during the first years after the Chernobyl accident was successful in reducing the external dose when its implementation was preceded by proper remediation assessment. However, the decontamination has produced a disposal problem due to the considerable amount of low level radioactive waste that was created. Secondary cross-contamination with radionuclides of cleaned up plots from surrounding areas has not been observed.
The most effective agricultural countermeasures in the early phase were exclusion of contaminated pasture grasses from animal diets and rejection of milk based on radiation monitoring data. Feeding animals with “clean” fodder was effectively performed in some affected countries. However, these countermeasures were only partially effective in reducing radioiodine intake via milk because of the lack of timely information about the accident and necessary responses, particularly for private farmers.
The greatest long term problem has been radiocaesium contamination of milk and meat. In the USSR and later in the CIS countries, this has been addressed by the treatment of land used for fodder crops, clean feeding and application of Cs-binders, such as Prussian blue, see FIG. 7, to animals that enabled most farming practices to continue in affected areas and resulted in a large dose reduction.
FIG. 7. Changes with time in the use of Prussian blue in the CIS countries (IAEA).
Application of agricultural countermeasures in the affected CIS countries substantially decreased since the middle of 1990s (to less extent in Belarus) because of economic problems. In a short time, this resulted in an increase of radionuclide content in plant and animal agricultural products.
In Western Europe, because of the high and prolonged uptake of radiocaesium in the affected extensive systems, a range of countermeasures are still being used for animal products from uplands and forests.
The following forest-related restrictions widely applied in the USSR and later in CIS countries and in Scandinavia have reduced human exposure due to residence in radioactively contaminated forests and use of forest products:
- Restrictions on public and forest worker access as a countermeasure against external exposure;
- Restricted harvesting of food products such as game, berries and mushrooms by the public that contributed to reduction of internal doses. In the CIS countries mushrooms are a staple of many diets and, therefore, this restriction has been particularly important;
- Restricted collection of firewood by the public to prevent exposures in the home and garden when the wood is burned and the ash is disposed of or used as a fertilizer; and
- Alteration of hunting practices aiming to avoid consumption of meat with high seasonal levels of radiocaesium.
Numerous countermeasures put in place in the months and years after the accident to protect water systems from transfers of radioactivity from contaminated soils were generally ineffective and expensive. The most effective countermeasure was the early restriction of drinking water and changing to alternative supplies. Restrictions on consumption of freshwater fish have also proved effective in Scandinavia and Germany, though in Belarus, Russia and Ukraine such restrictions may not always have been adhered to.