Natural and anthropogenic radionuclides concentration with heavy metals analysis of the sediments collected around Novaya Zemlya

Evaluation of succulent plants Echeveria elegans as a biomonitor of heavy metals and radionuclides

This work evaluates the use of Echeveria elegans as a biomonitor of metals and radionuclides, using semi-urban soils as a study area. The study area is exposed to various trace elements of concern for various social groups in nearby localities. The quantification of metals and radionuclides was performed by X-ray fluorescence spectrometry and gamma spectrometry, respectively. Cumulative frequency distribution curves, descriptive statistics, and multivariate analysis were used to estimate the local geochemical baseline and identify geochemical and anthropogenic patterns of metals and radionuclides from topsoil and E. elegans. The evaluation of contaminants and the contribution of possible exposure routes (topsoil and atmospheric deposition) was performed with the enrichment factor (EF) and the relative concentration factor (CFR). The results suggest that the plant does not present significant physical stress due to the environmental conditions to which it was exposed. Likewise, it can bioaccumulate heavy metals from natural and anthropogenic sources. The quantification of radionuclides in the plant is below the detection limits, indicating a low bioavailability and transfer factor. The CFR and EF results showed that the plant accumulates metals from the topsoil and atmospheric deposition. The bioaccumulation mechanism would be related to the functioning of Crassulaceae Acid Metabolism (CAM). In topsoil, the organic acids of the plant would modify the solubility of the metals present in an insoluble form in the soil, acting as ligands and, subsequently, following the transport route of these metabolites. In atmospheric deposition, the metals deposited in the leaves would be incorporated into the plant through the opening of the stomata because of the capture of CO2 (at night, day, or during environmental stress) by the CAM. Overall, the evidence showed that the succulent can be used as a biomonitor of heavy metals. However, additional studies are required to determine its usefulness as a radionuclide biomonitor.

Sedimentary environmental quality of a biosphere reserve estuary in southwestern Iberian Peninsula

The Huelva estuary is formed by the common mouths of the Odiel and Tinto Rivers, and inside this ecosystem is the biosphere reserve of the Odiel saltmarshes. This ecosystem has been historically affected by acid mine drainage (AMD) and by releases of pollutants from five phosphoric acid industrial plants and phosphogypsum (PG) waste stacks located in the area. This study carried out a comprehensive assessment of the environmental impact of the biosphere reserve of the Odiel saltmarshes. To this end, it was necessary to find a suitable sedimentary background (Piedras River in our case). To quantify this impact, several pollution indexes were used. According to the values reached by the indexes, this impact was classified as "serious" pollution for most trace elements, excepting the deepest layers, and "low-moderate" pollution for the 238U-series radionuclides, while no pollution for the 232Th-series and 40K radionuclides was found as expected.

Investigating radiation profiles and conducting risk assessment for ecological and environmental components on Vaan and Koswari islands in the Tuticorin group of islands, India

Natural radioactive concentration assessment was conducted on sediment, water, and biota obtained on Vaan and Koswari islands in the Tuticorin group of islands, Tamil Nadu, India. For biotic and abiotic components, radiation profiles such as gross alpha, beta, primordial radionuclide, polonium, and lead analyses were performed. The gross α and β range from BDL to 15.18 ± 1.7 Bq/kg and 40.43 ± 4.9 Bq/kg to 105.12 ± 11.7 Bq/kg, respectively. Primordial radionuclides were analyzed using Nal(TI)-based scintillator with PC-MCA, and the concentrations ranged from 13.43 ± 3.3 Bq/kg to 30.97 ± 9.6 Bq/kg with a mean of 21.31 ± 2.7 Bq/kg for 238U; for 232Th, the values ranged from 11.09 ± 2.6 Bq/kg to 33.55 ± 9.5 Bq/kg with an average value of 23.89 ± 3.7 Bq/kg; and for 40 K, the values are 93.33 ± 27.3 Bq/kg to 219.91 ± 39.6 Bq/kg with an average value of 148.27 ± 21.7 Bq/kg. The present study values are lesser than the world average values. 210Po and 210Pb concentrations with an average value were determined to be 33.13 Bq/L and 16.56 Bq/L, 47.55 Bq/L and 22.37 Bq/L in the water sample, and 50.437 Bq kg1 and 62.012 Bq kg1, 46.99 Bq/kg and 58.625 Bq/kg in sediments of Vaan island and Koswari island. The concentrations of 210Po and 210Pb of Pogonias cromis were 19.27 ± 1.5 Bq/kg and 8.27 ± 1.01 Bq/kg, Belonidae 28.54 ± 2.4 Bq/kg and 18.32 ± 2.3 Bq/kg, Lepisosteidae 18.68 ± 1.4 Bq/kg and 11.17 ± 1.8 Bq/kg. The committed effective dosage was determined to be 35.74-54.61 µSv/y for 210Po and 25.39-56.25 µSv/y for 210Pb, in which the 210Pb value is lower; however, the 210Po value is higher than the global average value. The annual committed effective dosage as well as the radiological hazard indices were assessed and found to be much below the global average and the recommended limit, respectively. This research provides an extensive analysis of natural background radiation and establishes a baseline report on the radiological profile of biotic and abiotic factors in the Tuticorin group of islands, namely Vaan and Koswari, in Tamil Nadu, India.

Radioactivity of anthropogenic and natural radionuclides in marine sediments of the Chaun Bay, East Siberian Sea

Natural radioactive isotopes serve as a useful proxy of geological and geochemical processes in marine environment, while radiocesium serves as an indicator of man-made contamination. Monitoring of natural and anthropogenic radioactivity under conditions of the climate changes in the Arctic region is of high importance in investigations of this natural system. For the first time, we report the data on spatial distribution of natural (232Th, 226Ra, 40K) and anthropogenic (137Cs) radionuclide activities in the marine sediments from Chaun Bay (East Siberian Sea). The measured activity concentrations varied in the range 23.7-77.9 (mean 39.2) Bq kg-1 for 232Th, 16.5-39.3 (mean 26.6) Bq kg-1 for 226Ra, 535-991 (mean 726) Bq kg-1 for 40K, and 0.5-4.7 (mean 2.0) Bq kg-1 for 137Cs. The radiocesium level in the sediments showed no local sources of anthropogenic pollution in the Chaun Bay, while the average activity concentration of 40K was 1.8 times higher than worldwide.