Data comprise water chemistry measurements (major alkali and alkali-earth element water concentrations and trace element concentrations) recorded over two years at seven lakes in Belarus and Ukraine at distances from 1.5 to 225 km of the Chernobyl Nuclear Power Plant (CNPP). The lakes include Glubokoye, Yanovsky lakes and Cooling Pond (high (H) contaminated lakes), Svyatoye Lake (medium (M) contaminated lake) and Stoyacheye, Dvoriche and Gorova lakes (low (L) contaminated lakes). Full details about this dataset can be found at https://doi.org/10.5285/b29d8ab8-9aa7-4f63-a03d-4ed176c32bf3

Data comprise sample site information, dose rate, radionuclide (zirconium-95, niobium-95, ruthenium-106, caesium-134, caesium-137 and cerium-144) deposition, and exchangeable caesium-134 and 137 in soils collected from within a 60 km radius of the Chernobyl nuclear power plant (ChNPP) in 1987 following the Chernobyl nuclear accident on 26th April 1986. The work was carried out by the Ukrainian Institute of Agricultural Radiology (UIAR), a division of National University of Life and Environmental Sciences of Ukraine. Funding for preparing this data set was provided by the TREE project (funded by NERC, the Environment Agency and Radioactive Waste Management Ltd under the RATE programme) and associated iCLEAR projects (funded by NERC). Full details about this dataset can be found at https://doi.org/10.5285/a408ac9d-763e-4f4c-ba72-73bc2d1f596d

Data comprise health, reproductive status and relative abundance of mature perch and roach collected in September 2014, March 2015, June 2015 and September 2015 from lakes in Belarus and Ukraine. Measurements presented include age, weight, length, presence of external signs of disease and presence of macroscopic tumors. The Fulton condition index (K), hepatosomatic index (HSI) and gonadosomatic index (GSI) of fish are also presented. The lakes (selected according to hydrological properties and long-term exposure to a gradient of radiation dose) are situated at distances from 1.5 to 225 km of the Chernobyl NPP. Glubokoye, Yanovsky lakes and Cooling Pond are the high (H) contaminated lakes, Svyatoye Lake is a medium (M) contaminated lake, and Stoyacheye, Dvoriche and Gorova lakes are the low (L) contaminated lakes. Full details about this dataset can be found at https://doi.org/10.5285/02a53248-1bfd-4f1e-8f76-888551635c98

Data comprise a catalogue of motion activated digital trap camera images of Eurasian Lynx (Lynx lynx (L., 1758)) obtained from motion-activated digital trap cameras located within the Chornobyl Exclusion Zone, Ukraine (CEZ) over multiple years (2012-2018). Images of Eurasian lynx obtained from the cameras are included as part of the dataset. The data were obtained from three research projects: (1) NatEnvPr - Studies conducted 2012–2018 (2) TREE - Studies conducted 2014–2016 and (3) RED FIRE - Studies conducted 2016–2017 The cameras for all projects were setup with the aim to capture images of medium-large mammals; the studies were not designed to obtain quantitative assessments of abundance and density of Eurasian lynx across the CEZ. No bait was used during any of the studies. Full details about this dataset can be found at https://doi.org/10.5285/c099d04e-72e0-4ee9-ac72-11dc004ec1f6

The data comprise measurements of the ‘soluble’, ‘chemically exchangeable’ and ‘isotopically exchangeable’ U concentrations in a diverse set of soils following experimental addition of UO22+ and incubation in the laboratory under controlled temperature conditions for ca. 1.7 years. The long term behaviour of U in aerobic soils was studied by conducting a laboratory-based experiment in which a set of 20 topsoils from central England with contrasting properties (e.g. pH, organic matter content, land use) were contaminated with a solution containing UO22+ in soluble form and incubated in the dark, in a moist but aerobic condition, at a temperature of 10oC for 619 days. The transformations of U in each soil microcosm were periodically monitored by means of soil extractions conducted on subsamples of incubated soils. The resulting dataset enabled quantification of the kinetics of UO22+ transformations in aerobic soils and the relationships with soil properties and land uses (arable, grassland and moorland/woodland). The dataset will be useful in developing models of long-term U bioavailability in aerobic soils under temperate conditions. Full details about this dataset can be found at https://doi.org/10.5285/0d8b2aea-574c-4cff-a8bd-17115a0b90fc

Data comprise audio files captured using a Wildlife Acoustics SM3 Songmeter located on an overgrown unpaved road close to several abandoned houses with deciduous trees (including fruit trees in former gardens) in the abandoned village of Buryakovka in the Chernobyl Exclusion Zone, Ukraine. A single continuous recording of twelve hours of audio from midday until midnight on the 25th June 2015 was manually annotated by an expert (using Raven Pro interactive sound analysis software). The dataset comprises the resultant five wave files (stereo .wav sampled at 48 kHz) and five annotation files (text files with the same name as the associated wave file). Full details about this dataset can be found at https://doi.org/10.5285/be5639e9-75e9-4aa3-afdd-65ba80352591

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

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

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

[This dataset is embargoed until August 14, 2023]. 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