Environmental impact of the accident

The reactor released radioactive materials continuously in the next ten days after the explosion at Chernobyl on 26 April 1986. Materials released to the atmosphere were widely dispersed and eventually deposited onto the earth's surface. Open surfaces, such as roads, lawns and roofs, were most heavily contaminated. Residents near the nuclear power stations were evacuated immediately. Wind, rain and remedial efforts contributed to reduce surface contamination, but led to secondary contamination of underground water. At present, the radiation in air has returned to the background level in most of the settlements.

Following the accident, animals and vegetation in forest and mountain areas had taken up high levels of radioactive Caesium. To prevent the dispersion of radionuclides by forest fires, surface layer of soil was removed and dead trees were cut down and buried. Re-forestation and sowing of grasses were also undertaken to prevent the spread of soil contamination. The radiation levels in mushrooms, berries and hunted animals were persistently high. Transfer of radioactive Caesium from lichen to reindeer meat and in turn to human was observed in the Arctic and sub-Arctic areas. Some restrictions on hunting were put in force to minimize ingestion of contaminated food.

Through deposition, the radioactivity polluted the surface water in the river, lake and reservoirs, affecting fishery and drinking water. Contamination of surface water bodies in most places declined quickly through dilution, physical decay, and uptake of radioactivity in bed sediments and catchment soils. The contamination of surface water had not posed a public health problem since the accident. However, in view of the large quantities of radioactivity deposited in the catchment areas of water bodies in the contaminated regions around Chernobyl, the local authority is continuing the monitoring to ensure that washout from the catchment areas will not contaminate drinking water. In those areas where the radiation levels remain high, such as the exclusion zone within a 30 kilometres radius from the nuclear power station and in some 'closed' lakes with no outflowing streams, restriction on fishing and water use will be maintained.

The new and modern city of Slavutich, some 50 km from the
Chernobyl Nuclear Power Station, built after the accident.
(Source: Petr Pavlicek/IAEA)