Radiocaesium in Tricholoma spp. from the Northern Hemisphere in 1971–2016

A considerable amount of data has been published on the accumulation of radiocaesium ( 134Cs and particularly, 137Cs) in wild fungi since the first anthropogenically influenced releases into the environment due to nuclear weapon testing, usage and subsequently from major accidents at nuclear power plants in Chernobyl (1986) and Fukushima (2011). Wild fungi are particularly susceptible to accumulation of radiocaesium and contamination persists for decades after pollution events. Macromycetes (fruiting bodies, popularly called mushrooms) of the edible fungal species are an important part of the human and forest animal food-webs in many global locations. This review discusses published occurrences of 134Cs and 137Cs in twenty four species of Tricholoma mushrooms sourced from the Northern Hemisphere over the last five decades, but also includes some recent data from Italy and Poland. Tricholoma are an ectomycorrhizal species and the interval for contamination to permeate to lower soils layers which host their mycelial networks, results in a delayed manifestation of radioactivity. Available data from Poland, over similar periods, may suggest species selective differences in accumulation, with some fruiting bodies, e.g. T. portentosum, showing lower activity levels relative to others, e.g. T. equestre. Species like T. album, T. sulphurescens and T. terreum also show higher accumulation of radiocaesium, but reported observations are few. The uneven spatial distribution of the data combined with a limited number of observations make it difficult to decipher any temporal contamination patterns from the observations in Polish regions. When data from other European sites is included, a similar variability of 137Cs activity is apparent but the more recent Ukrainian data appears to show relatively lower activities. 40K activity in mushrooms which is associated with essential potassium, remains relatively constant. Further monitoring of 137Cs activity in wild mushrooms would help to consolidate these observations

A Review of the Occurrence of Alpha-Emitting Radionuclides in Wild Mushrooms

Alpha-emitting radioisotopes are the most toxic among all radionuclides. In particular, medium to long-lived isotopes of the heavier metals are of the greatest concern to human health and radiological safety. This review focuses on the most common alpha-emitting radionuclides of natural and anthropogenic origin in wild mushrooms from around the world. Mushrooms bio-accumulate a range of mineral ionic constituents and radioactive elements to different extents, and are therefore considered as suitable bio-indicators of environmental pollution. The available literature indicates that the natural radionuclide 210Po is accumulated at the highest levels (up to 22 kBq/kg dry weight (dw) in wild mushrooms from Finland), while among synthetic nuclides, the highest levels of up to 53.8 Bq/kg dw of 239+240Pu were reported in Ukrainian mushrooms. The capacity to retain the activity of individual nuclides varies between mushrooms, which is of particular interest for edible species that are consumed either locally or, in some cases, also traded on an international scale. The effective radiation dose from the ingestion of this food can reportedly range from 0.033 µSv/kg dw to 26.8 mSv/kg and varies depending on the country. Following pollution events, such consumption may expose consumers to highly radiotoxic decay particles produced by alpha emitters

Plutonium isotopes 238Pu, 239+240Pu, 241Pu and 240Pu/239Pu atomic ratios in the southern Baltic Sea ecosystem

The paper summarizes the results of plutonium findings in atmospheric fallout samples and marine samples from the southern Baltic Sea during our research in 1986-2007. The activities of 238Pu and 239+240Pu isotopes were measured with an alpha spectrometer. The activities of 241Pu were calculated indirectly by 241Am activity measurements 16-18 years after the Chernobyl accident. The 240Pu/239Pu atomic ratios were measured using accelerator mass spectrometry (AMS). The 241Pu activities indicate that the main impact of the Chernobyl accident was on the plutonium concentration in the components of the Baltic Sea ecosystem examined in this work. The highest 241Pu/239+240Pu activity ratio was found in sea water (140 ± 33). The AMS measurements of atmospheric fallout samples collected during 1986 showed a significant increase in the 240Pu/239Pu atomic ratio from 0.29 ± 0.04 in March 1986 to 0.47 ± 0.02 in April 1986

Alpha spectrometry in radiochemical analysis and its application in the study of the natural environment

Alpha spectrometry is a highly sensitive and modern measurement technique which can be used to radiochemical and radiological studies of the natural environment. In the paper were presented the results on application of alpha spectrometry in the study for determination of natural (210Po, 210Pb, 234U, 238U) and artificial (238Pu, 239+240Pu and 241Pu) alpha and beta radionuclides in environment of Poland and Baltic Sea. Amongst the radionuclides, alpha particle emitters play the most important role as they are highly radiotoxic to organisms. The concentrations of alpha radionuclides in the environmental samples of Poland are characterized based on the environmental materials collected between 1998 and 2009. Biogeochemistry of polonium, uranium and plutonium in the southern Baltic Sea ecosystem combined with the use of radioactive disequilibrium 210Po/210Pb, 234U/238U and 238Pu/239+240Pu and 241Pu/239+240Pu allows you to identify the sources of these radionuclides in natural ecosystems. It also allows to determine their circulation in the environment (e. g. to assess the impact of the Chernobyl nuclear accident on the radioactive contamination of Poland).

Vertical distribution of ²⁴¹Am in the southern Baltic Sea sediment profiles

The contamination of the Baltic Sea with radioactive substances occurred due to the global fallout of atmospheric nuclear weapon tests and the Chernobyl disaster. The knowledge of 241Am in the sediments of the Baltic Sea is limited. Thus, this study aimed to determine 241Am in sediment cores collected from the southern Baltic Sea. Time-based distributions were derived from age-depth profiles using the 210Pb dating method and further corroborated by 137Cs profiles. The activities of 241Am were measured by alpha spectrometry after radiochemical purification. The results show divergences in the concentrations of 241Am at the local level, varying from 0.017 ± 0.001 Bq·kg−1 at the Gotland Basin station to 3.19 ± 0.23 Bq·kg−1 in the Gdańsk Basin. These findings enhance our understanding of the radioactive contamination levels in the Baltic Sea and serve as a crucial reference dataset for future assessments and management strategies to mitigate the environmental impact of radionuclides in the region