Notable case, Pryp'jat' / Chornobyl, Kyiv Oblast, Ukraine
Chernobyl Exclusion Zone
Чорнобильська зона відчуження
The area evacuated around the Chernobyl nuclear power plant after reactor 4 exploded on 26 April 1986. It is the largest territory in the world taken out of use because of radioactive contamination, and one of the first places where plants were tried for removing radionuclides from water.
At a glance
- Status
- Contained
- Area
- 260,000 ha on land1
- Activity
- 1986–1986
- People affected
- 115,000 (1986)2
- Media
- soil, surface water, sediment, groundwater, living organisms, air
- Kind of site
- nuclear, accident, power plant
- Area. About 2,600 km² on the Ukrainian side according to the Wikipedia entry read in 2026; the contaminated Belarusian side is a separate reserve.
- People affected. People evacuated in 1986 (WHO). Wikipedia gives 91,200 evacuated from the initial zones and a further 53,000 between 1990 and 1995.
Contaminants
Radionuclides
Status
Contained
Access is forbidden or controlled. The last reactor was shut down in 2000; about 3,000 workers carry out decommissioning and monitoring, and roughly 200 self-settlers still live inside (figures as given by Wikipedia, read in 2026). The zone has been closed to visitors since 2022.
Story
On 26 April 1986 reactor 4 of the Chernobyl plant, in what was then Soviet Ukraine, exploded during a test. The fire spread iodine-131, caesium-134 and caesium-137, together with strontium-90 and plutonium, over Ukraine, Belarus, Russia and much of Europe. A 30 km exclusion zone was set up on 2 May; its borders were redrawn in 1991 according to contamination levels and extended in 1997.
About 115,000 people were evacuated in 1986 (WHO figure). Between 1986 and 1990 some 530,000 registered "liquidators" worked on the clean-up. Iodine-131 decayed within weeks; caesium-137 and strontium-90, with half-lives of about thirty years, remain in soil, sediment and forest biomass, and wildfires can put them back into circulation.
Today the zone is both a decommissioning site and, in practice, a large area with no settled human presence, protected since 2016 as a biosphere reserve. Russian troops occupied it from 24 February to early April 2022.
Timeline
- 198626 April: reactor 4 explodes. 2 May: the 30 km exclusion zone is established.
- 1991A law redraws the zone's borders according to measured contamination.
- 1997The Poliske and Narodychi areas are added to the zone.
- 200015 December: reactor 3, the last one operating, is shut down.
- 2016The Chernobyl Radiation and Environmental Biosphere Reserve is created.
- 2022Russian military occupation from 24 February to early April.
Health
According to WHO, 134 workers developed acute radiation sickness and 28 died within the first three months. By 2005 more than 6,000 thyroid cancers had been diagnosed in people exposed as children or adolescents, largely attributed to iodine-131 in milk. The average dose was about 30 mSv for evacuees and 120 mSv for recovery workers.
Remediation
- 1986evacuation and access restrictionEvacuation of the population and a ban on residence and farming inside the zone.
- 2000decommissioningShutdown of the last reactor and start of the plant's decommissioning.
Plants and fungi at this site
PhytoremediationField pilot
Helianthus annuus
Rhizofiltration demonstration in a pond near the plant: sunflowers grown on floating rafts with their roots in the water, to remove caesium-137 and strontium-90.
Outcome The University of Hawaii fact sheet reports a 90% reduction in two weeks, with roots concentrating the radionuclides up to 8,000-fold. The review by Lincoln and Noori (2025) notes that after nearly forty years of physical, chemical and biological attempts the contamination persists.
PhytoremediationField scale
Brassica juncea, Amaranthus spp.
Dushenkov with Mikheev, Prokhnevsky, Ruchko and Sorochinsky tested 20 soil amendments to bring caesium into solution, compared plant species and grew three successive crops of Indian mustard in one season on an experimental plot.
Outcome A modest result: the three crops gave only a small decrease in caesium-137 activity in the top 15 cm of soil. Amaranths accumulated more than the other species and ammonium salts were the most practical amendment. The authors conclude that further improvement is needed before the technique is usable. The famous trials with sunflowers on rafts in a pond and with hemp are cited everywhere, but no primary source with the measurements was found.
From the literature
Species that acted on one of this site's contaminants in at least one study. The list is automatic and takes no account of this site's soil, concentrations or climate.
Plants
- Amaranthus retroflexusRedroot pigweedCaesium-137Strontium-90Evidence: field
- Brassica junceaIndian mustardStrontium-90Caesium-137Evidence: field
Fungi
- Boletus edulisKing bolete, porciniCaesium-137Evidence: survey of wild specimens
Nearby
Sources
- Radiation: The Chernobyl accident (Q&A), WHO
- Chernobyl exclusion zone, Wikipedia, 2026
- Phytoremediation potential for radionuclide removal following the Chernobyl Nuclear Power Plant disaster (repository record), Merrimack College ScholarWorks, 2025
Draft compiled from public sources, not yet reviewed.