Data comprise plot details and radionuclide activity concentrations for Sr-90, Cs-137, Am-241, Pu-238, Pu-239 and Pu-240 in ‘grassy’ vegetation and soil. These radionuclide activity concentrations have been used to make estimations of total weighted absorbed doses to grassy vegetation, deciduous trees and bacteria; no dose rate estimates for grassy vegetation have been made for those sites where grassy vegetation was absent. Radiation from the 1986 Chernobyl nuclear power plant accident killed coniferous trees in a 4-6 km2 area of forest to the west of the power plant. This area is now known as the 'Red Forest’ and it has subsequently regenerated with understorey vegetation and deciduous trees; it is the most anthropogenically contaminated radioactive ecosystem on Earth. In July 2016 a severe fire burnt (to varying degrees) c. 80 percent of the Red Forest; this presented a unique opportunity to study the impact of radiation on the recovery of forest ecosystems exposed to a secondary stressor (fire). To investigate this, in September 2017 the RED FIRE project set up sixty study plots in the Red Forest (in burnt and unburnt areas) with a further nine plots established close to Buriakivka village (approximately 8 km from the Red Forest). Vegetation samples from each plot were harvested using shears in September 2017. Each sample was sorted into ‘grassy’ and ‘other’ vegetation; these were air-dried (20-25 degrees Celsius) and the grassy vegetation samples homogenised prior to radionuclide analyses. Soil core samples collected in September 2017 were bulked, homogenised and sub-samples taken for determination of pH and percentage moisture determined by oven drying (approximately 60 degrees Celsius) to a constant mass. The remaining soil sample was used for the determination of radionuclide activity concentrations; prior to analyses, these samples were dried at approximately 80 degrees Celsius. This work was funded by the NERC, Grant Ref: NE/P015212/1 (RED FIRE: Radioactive Environment Damaged by fire: a Forest In Recovery) Full details about this dataset can be found at https://doi.org/10.5285/60782622-7bfa-4615-a9e3-0a802a9f4674

Data comprise site location, soil chemistry (pH, soil moisture), soil radionuclide activity concentrations (the isotopes measured were: Americium-241, Caesium-137, Plutonium-238, -239 and -240, Strontium-90 (K-40 and U-238 activity concentrations were estimated from stable element data) and soil biological activity (derived from application of bait lamina sticks) at 18 sites in the Chernobyl Exclusion Zone (CEZ), Ukraine in 2016; data for four sites in 2005 are also presented. Estimate absorbed radionuclide dose rates to soil invertebrates and bacteria are also presented. The primary purpose of these data was to enable an evaluation of the potential impact of radiation on soil organisms. The work was carried out by UKCEH, Chernobyl Centre for Nuclear Safety and the University of Salford. Funding for this work was via the TREE project funded by NERC, Environment Agency and Radioactive Waste Management Ltd. under the RATE programme. Full details about this dataset can be found at https://doi.org/10.5285/19babe1c-b3a3-488c-b4fe-ebb4ab9237d8

A large area of the Chernobyl Exclusion Zone was affected by severe wildfires in April 2020. This dataset presents the results of a study conducted following the fire in September/October 2020 to measure the migration of 137Cs and 90Sr in soils collected from three study sites located within forested areas on the left bank of the Pripyat River within the Chornobyl Exclusion Zone. Data comprise activity concentrations of 90Sr and 137Cs measured in soil samples. Soils were sampled layer-by-layer (0-10 cm, 10-20 cm, 20-30 cm, 40-50 cm, 50-60 cm, 60-70 cm, 70-80 cm, 80-90 cm, and 90-100 cm) from three locations at each of the three study sites. At each of the three study sites, circular plots were established on September 21st 2020 and soil samples collected; the circular plots were of different sizes dependent upon tree density. On October 8th 2020 a tripod was installed at the centre of each study site; the plot coordinates were noted and information on the trees present recorded (diameter, height and condition (dead or alive)). The dataset comprises two files. These files contain information on site and sampling locations, date of sampling, Cs-137 and Sr-90 activity concentration ((Bq kg-1) and analysis uncertainty (2-sigma)) in soil samples taken at 10cm intervals to a depth of 1 m, tree condition after wildfire (measured October 8th 2020); tree diameter (measured at a height of 1.3 m above ground level) and tree height (m). Full details about this dataset can be found at https://doi.org/10.5285/72c05810-eb66-49e1-9107-dec8cde3b07e

Measurements of sediment properties (including organic and carbonate content), radionuclides (210Pb, 137Cs, 241Am) and elements (including mercury, nickel, copper, zinc, and lead) in lake sediment successions. Radionuclide dating provides a reliable chronology of sediment ages from the mid-19th century (sometimes only 20th century) to the present (2016). The dataset comprises a standardised matrix of multiple measured sediment variables (element values per mass) against stratigraphic depth for 8 lakes. In some water bodies multiple core datasets exist. Full details about this dataset can be found at https://doi.org/10.5285/4b4a2388-fea2-48e8-8d61-4b93ada479bb

This dataset includes individual passive detector measurements of radon Rn-222 in the air of artificial burrows, Rn-222 measurements by instrumentation in soil gas of interstitial soil pores and burrow air, gamma analyses results for soil samples and, soil moisture and temperature data. Estimates of absorbed dose rates to wildlife from exposure to natural background radionuclides are required to put estimates of dose rates arising from regulated releases of radioactivity and proposed benchmarks into context. These data are from a study conducted at seven sites in northwest England (comprising broadleaved and coniferous woodlands, scrubland and pastures). Passive track etch detectors were used to measure the Rn-222 concentrations in artificial burrows over a period of approximately one year (July 2009 to June 2010). Instrumented measurements of burrow air and soil pore gas were also conducted in October 2009. The data result from a study funded by NERC-CEH and the England & Wales Environment Agency. Full details about this dataset can be found at https://doi.org/10.5285/2641515F-5B76-445C-A936-1DA51BF365AD

Following the Fukushima accident in March 2011, grass samples were collected from 42 sites around Great Britain during April 2011. Iodine-131 was measurable in grass samples across the country with activity concentrations ranging from 10 to 55 Bq per kg dry matter. Concentrations were similar to those reported in other European countries. Rainwater and some foodstuffs were also analysed from a limited number of sites. Of these, I-131 was only detectable in sheep's milk (c. 2 Bq/kg). Caesium-134, which can be attributed to releases from the Fukushima reactors, was detectable in six of the grass samples (4-8 Bq/kg dry matter); 137Cs was detected in a larger number of grass samples although previous release sources (atmospheric weapons test and the 1986 Chernobyl and 1957 Windscale accidents) are likely to have contributed to this. All data and information for this sampling are available from this record. The data result from collaboration between CEH and the University of Stirling. Full details about this dataset can be found at https://doi.org/10.5285/1a91c7d1-ec44-4858-9af2-98d80f169bbd

The data presented here comprise a catalogue of 61736 camera trap images obtained during the period June - November 2020 (this period is described within the dataset as 'setup 1'). Following the explosion at the Chornobyl nuclear power plant in April 1986, a 5000 km2 exclusion zone surrounding the plant was created; people and farm animals were subsequently evacuated from the area. In April 2020 there were severe wildfires within the Ukrainian part of the exclusion zone (2600 km2) where approximately 870 km2 was burnt. The NERC-funded CHAR project conducted a study which involved placing motion activated digital camera traps at three sites (each covering an area of 80 km2) within the Ukrainian exclusion zone from June 2020 - August 2021 to assess large mammal activity following the fire. Thirteen cameras were randomly located at each site; all camera deployment locations had been used in a previous study 2014-2015 (https://tree.ceh.ac.uk/content/chernobyl-webcams). All the images obtained during June - November 2020 are included as part of the dataset with the exception of those images containing people, vehicles or members of the CHAR research team setting up and servicing the cameras; these images have been catalogued but they are not included in the dataset to protect privacy. Information on camera deployment periods, site characteristics and descriptions of each camera location (e.g. geographic coordinates, estimates of ambient dose rate, description of animal trails or tracks and the extent of fire damage in vicinity of where the camera is mounted) have also been included as part of the dataset. Staff from the Chornobyl Center for Nuclear Safety deployed, maintained and downloaded information from the cameras and provided field notes and observations of habitat. UKCEH staff populated the dataset using the information provided. Full details about this dataset can be found at https://doi.org/10.5285/9bd7754d-ea87-4b35-bec1-f39d5cc76db6

Data comprise biological and ecological half-life values for marine, freshwater, terrestrial and riparian organisms. The database includes 1908 biological half-life values for 52 elements across a range of wildlife groups (marine, freshwater, terrestrial and riparian). The compilation of values from a range of sources was conducted by an international working group under the auspices of an International Atomic Energy Agency programme. Full details about this dataset can be found at https://doi.org/10.5285/b95c2ea7-47d2-4816-b942-68779c59bc4d

Data comprise concentrations of elements in ashed fish sampled from lakes in the English Lake District in 2012 and 2013. Fish were collected from three lakes (Windermere, Bassenthwaite Lake and Derwent Water) by the Centre for Ecology & Hydrology (CEH) Lake Ecosystems group. Fish species collected were Roach (Rutilus rutilus), Perch (Perca fluviatilis), Ruffe (Gymnocephalus cernuus), Brown trout (Salmo trutta), Pike (Esox lucius) and Vendace (Coregonus albula). All samples were ashed prior to analysis by ICPMS or ICPOES to determine elemental concentrations. Full details about this dataset can be found at https://doi.org/10.5285/ed90df1b-462c-46bb-afbd-59794fb03f6b

Data comprise radiocaesium concentrations in soil, vegetation, wildlife and fungi analysed from samples collected from throughout Great Britain after the 1986 Chernobyl accident by the Centre for Ecology & Hydrology (CEH), formerly the Institute of Terrestrial Ecology (ITE). National level vegetation surveys were conducted in May 1986, October 1986 and Spring 1987. More intensive surveys of vegetation (grass and heather) and wildlife (grouse, fox, etc.) in restricted areas were carried out in Cumbria, Wales and North Yorkshire in 1989, 1990, 1991 and 1993. Surveys of fungi were carried out between 1994 and 1997. The data are suitable for interpolation to create spatially variable surfaces suitable for input into models. Full details about this dataset can be found at https://doi.org/10.5285/d0a6a8bf-68f0-4935-8b43-4e597c3bf251