Activity disequilibrium between 234U and 238U isotopes in natural environment

Abstract

The aim of this work was to calculate the values of the 234 U/ 238 U activity ratio in natural environment (water, sediments, Baltic organisms and marine birds from various regions of the southern Baltic Sea; river waters (the Vistula and the Oder River); plants and soils collected near phosphogypsum waste heap in Wiślinka (Northern Poland) and deer-like animals from Northern Poland. On the basis of the studies it was found that the most important processes of uranium geochemical migration in the southern Baltic Sea ecosystem are the sedimentation of suspended material and the vertical diffusion from the sediments into the bottom water. Considerable values of the 234 U/ 238 U are characterized for the Vistula and Oder Rivers and its tributaries. The values of the 234 U/ 238 U activity ratio in different tissues and organs of the Baltic organisms, sea birds and wild deer are varied. Such a large variation value of obtained activity ratios indicates different behavior of uranium isotopes in the tissues and organisms of sea birds and wild animals. This value shows that uranium isotopes can be disposed at a slower or faster rate. The values of the 234 U/ 238 U activity ratio in the analyzed plants, soils and mosses collected in the vicinity of phosphogypsum dumps in Wiślinka are close to one and indicate the phosphogypsum origin of the analyzed nuclides. Uranium isotopes 234 U and 238 U are not present in radioactive equilibrium in the aquatic environment, which indicates that their activities are not equal. The inverse relationship is observed in the terrestrial environment, where the value of the of the 234 U/ 238 U activity ratio really oscillates around unity.

Radionuclides (222Rn, 226Ra, 234U, and 238U) Release in Natural Waters Affected by Coal Mining Activities in Southern Brazil

“…Deviations from the equilibrium between 234 U and 238 U in environmental samples are large, especially in the aquatic environment (Boryło and Skwarzec 2014), as can be seen for river waters from Figueira. The higher value of 234 U/ 238 U ratio for L1 (10.7) in the dry month may also be a result of other U sources (e.g., fertilizers, spring waters, dust, and sediments; Skwarzec et al 2002) in addition to mining effluents, considering that this point is located upstream the mine.…”

Natural radionuclides in plants, soils and sediments affected by U-rich coal mining activities in Brazil

“…The 234 U/ 238 U values did not change significantly for the analyzed soils (SC1 ¼ 1.20 ± 1.1; SC2 ¼ 1.12 ± 1.1). This fact may be a result of the contribution of the natural geological content of this element in the rocks to the soils from the study area (Boryło and Skwarzec, 2014). The 234 U/ 238 U values for coal (C1 ¼ 0.98 ± 0.96; C2 ¼ 0.81 ± 0.83) and coal ash (A1 ¼ 0.94 ± 0.93; A2 ¼ 1.07 ± 1.05) did not ranged pronounced, corroborating for this hypothesis.…”

“…Fundamental understanding of the differences in elements accumulation considering the biodiversity, especially for edible vegetables, might be very useful for predicting the fate of radionuclides (Willey, 2014). The radioactive disequilibrium can be an important tool for the prediction of radionuclides dynamic in the natural environment, for both biotic and abiotic components (Boryło and Skwarzec, 2014).…”

“…The radioactive imbalance based on the 234 U/ 238 U values was more pronounced in the case of soybean and wheat samples that exhibited isotopic ratios ranging from 0.36 to 65.91 (IAEA, 2010). Deviations from the equilibrium between 234 U and 238 U in environmental samples are large (Boryło and Skwarzec, 2014). The higher values of 234 U/ 238 U ratio may be a result of other U sources (e.g., fertilizers, spring waters, dust and sediments; Skwarzec et al (2002)) in addition to soils and mining effluents.…”

First insight into microbial community composition in a phosphogypsum waste heap soil

“…Currently, this area is subjected to reclamation, and was covered with sludge from wastewater treatment plants, which is characterized by the presence of heavy metals, such as copper, zinc, cadmium, lead, chromium and nickel; the area is also covered with vegetation. As phosphogypsum waste heap is a unique place on European scale, in recent years, a number of analyses were conducted in the neighborhood of this landfill in order to determine its impact on the local environment and ecosystem (Skwarzec et al, 2010;Boryłko & Skwarzec, 2013;Boryło & Skwarzec, 2014). Vol.…”