Bioaccumulation of polonium (210Po) and uranium (234U, 238U) in plants around phosphogypsum waste heap in Wiślinka (northern Poland)

Assessment of intake of 210Po and 210Pb isotopes from cow's milk in Poland

Milk has been known for its nutritional properties for centuries and is often the staple of the diet in many countries. Therefore, monitoring of milk composition seems to be a relevant task as it was the purpose of this study to compare levels of ²¹⁰Po and ²¹⁰Pb in several Polish voivodeships. The methodology was based on mineralization, loss on an inorganic matrix and concentration measurement on an alpha spectrometer. The concentrations of ²¹⁰Po and ²¹⁰Pb in collected milk samples were measured using alpha spectrometry and calculations, respectively. The results showed that the lowest concentration of ²¹⁰Po is 2.8 ± 0.2 mBq l^-1 and the highest is 56.3 ± 0.7 mBq l^-1 while the ²¹⁰Pb concentrations are in the range from 2.8 ± 0.2 to 44.0 ± 1.7 mBq l^-1. The associated annual effective doses for adults jmrange from 3.5 ± 0.1 to 11.0 ± 0.2 µSv a^-1 for ²¹⁰Po and from 2.0 ± 0.1 to 5.0 ± 0.1 µSv a^-1 for ²¹⁰Pb. The lowest doses were noticed in Kuyavian-Pomeranian Voivodeship and the highest values were found in Lesser Poland Voivodeship. The results show that the annual effective dose in individual provinces is not dangerous to health. However, there are significant differences between highly and lowly industrialized voivodeships.

Radioactivity of honey in central and southern Poland

In 2017, the Polish public consumed on average 0.61 kg of honey, while the European average consumption was 0.7 kg (Data on honey consumption in Poland, 2014) [http://www.portalspozywczy.pl]. The main point of this study was to investigate the ²¹⁰Po activity concentrations in different types of floral and non-floral honey, type of clad honey is made of and honey yield in honey available on the Polish market. Activity of ²¹⁰ Po in honey ranged from 0.006 ± 0.001 to 0.384 ± 0.004 Bq kg^-1 with effective dose 0.005 ± 0.001 to 0.281 ± 0.003 μSv/year. The activity in honey was measured by alpha-spectrometry. The concentration of radionuclide depends on the raw material used by bees and plant type. The highest concentration of ²¹⁰Po was observed in the honeydew honey and herbal honey.

Determination of 210Po in low-level wild bilberries reference material for quality control assurance in environmental analysis using extraction chromatography and α-particle spectroscopy

Certified reference materials (CRM) are being widely used for quality control assurance in environmental analysis. For certain CRM, the analytes and/or the range of concentrations are not be available or certified at all. The Joint Research Centre – Institute for Reference Materials and Measurements (JRC-IRMM) of the European Commission has issued a CRM of Wild Berries (IRMM-426) in order to validate radionuclide measurement methods for activity concentrations of the natural radionuclide 40K and the anthropogenic nuclides 90Sr and 137Cs, but not for 210Po. The aim of the work was to determine low-level activity concentration of 210Po in these wild berries. The activity concentration of 210Po was assessed by α-particle spectroscopy after dissolution of the sample by wet digestion and chemical isolation of Po by extraction chromatography. According to the time elapsed since sample collection, the results here shown can be useful not only for ultra low-level analysis of 210Po but also for 210Pb in the reference material.

210Po in popular medicinal herbs from Poland

Herbs are an important part of traditional medicine in Poland. Therefore, the aim of this study was the determination of polonium ²¹⁰Po in 48 selected medicinal herb samples from the Polish market. The activity concentrations of ²¹⁰Po were measured using alpha spectrometry. The activity concentration of ²¹⁰Po was in the range from 0.3 ± 0.1 to 28.2 ± 0.4 Bq kg^-1. The obtained results were compared with corresponding studies conducted worldwide. A higher ²¹⁰Po activity concentration was observed in the above-ground part of plants. The obtained results show that the highest ²¹⁰Po activity concentration was observed in evergreen plants and winter-hardy plants. Yet even infusions with 2 g of the most contaminated herbs examined were considered to be radiologically safe.

Polonium-210 in honey samples from southern Poland

Polonium (210Po) concentrations in different honey samples from Lower Silesian Voivodeship and Lesser Poland Voivodeship (southern Poland) were determined. Significantly higher 210Po concentrations were observed near mining heaps and former excavations versus background areas. Differences in 210Po concentrations were also observed for honeydew versus nectar honey and between the two voivodeships.

A study on possible use of Urtica dioica (common nettle) plants as uranium (234U, 238U) contamination bioindicator near phosphogypsum stockpile

The aim of this study was to determine uranium concentrations in common nettle (Urtica dioica) plants and corresponding soils samples which were collected from the area of phosphogypsum stockpile in Wiślinka (northern Poland). The uranium concentrations in roots depended on its concentrations in soils. Calculated BCF and TF values showed that soils characteristics and air deposition affect uranium absorption and that different uranium species have different affinities to U. dioica plants. The values of ²³⁴U/²³⁸U activity ratio indicate natural origin of these radioisotopes in analyzed plants. Uranium concentration in plants roots is negatively weakly correlated with distance from phosphogypsum stockpile.

A study on possible use of Urtica dioica (common nettle) plant as polonium (210)Po and lead (210)Pb contamination biomonitor in the area of phosphogypsum stockpile

The aim of this study was to test a possible use of Urtica dioica (common nettle) plant as a biomonitor of polonium (210)Po and lead (210)Pb contamination near phosphogypsum stacks by determining concentrations of these radionuclides in samples collected from the area of phosphogypsum stockpile in Wiślinka (northern Poland). The (210)Po and (210)Pb contents in roots depended on their concentrations in soils. Bioconcentration factor values from soil to root of the plant did not depend on (210)Po and (210)Pb contents in soils that leads to the conclusion that different polonium and lead species have different affinities to U. dioica plants. The main sources of both analyzed radionuclides in green parts of plants are wet and dry air deposition and transportation from soil. The values of (210)Po/(210)Pb activity ratio indicate natural origin of these radioisotopes in analyzed plants. (210)Po and (210)Pb concentration in U. dioica roots is negatively weakly correlated with distance from phosphogypsum stockpile.

Uranium ((234)U, (235)U and (238)U) contamination of the environment surrounding phosphogypsum waste heap in Wiślinka (northern Poland)

The aim of this work was to determine the uranium concentration ((234)U, (235)U and (238)U) and values of the activity ratio (234)U/(238)U in soil samples collected near phosphogypsum waste heap in Wiślinka (northern Poland). On the basis of the studies it was found that the values of the (234)U/(238)U activity ratio in the analyzed soils collected in the vicinity of phosphogypsum dump in Wiślinka are in most cases close to one and indicate the phosphogypsum origin of the analyzed nuclides. The obtained results of uranium concentrations are however much lower than in previous years before closing of the phosphogypsum stockpile. After this process and covering the phosphogypsum stockpile in Wiślinka with sewage sludge, phosphogypsum particles are successfully immobilized. In the light of the results the use of phosphate fertilizers seems to be a major problem. Prolonged and heavy rains can cause leaching accumulated uranium isotopes in the phosphogypsum stockpile, which will be washed into the Martwa Wisła and on the fields in the immediate vicinity of this storage.

The radiological impact of phosphogypsum stockpile in Wiślinka (northern Poland) on the Martwa Wisła river water

The aim of this work was to determine the concentrations of uranium (234U, 235U, 238U), polonium (210Po) and lead (210Pb) radioisotopes in water samples and to explore the impact of the phosphogypsum stack on the Martwa Wisła waters. The 238U, 210Po and 210Pb concentrations in analyzed water samples reached maximum values of 11.7 ± 0.3, 2.0 ± 0.1 and 3.2 ± 0.1 mBq L-1 and activity ratios were maximally 1.18 ± 0.01 for 234U/238U, 0.041 ± 0.018 for 235U/238U and 0.69 ± 0.10 for 210Po/210Pb. The obtained results suggest that this impact is rather insignificant and does not affect significantly the Martwa Wisła river.

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

The aim of this work was to calculate the values of the 234U/238U 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 234U/238U are characterized for the Vistula and Oder Rivers and its tributaries. The values of the 234U/238U 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 234U/238U 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 234U and 238U 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 234U/238U activity ratio really oscillates around unity.

A study on lead (210Pb) and polonium (210Po) contamination from phosphogypsum in the environment of Wiślinka (northern Poland)

The results of polonium ((210)Po) and lead ((210)Pb) determination in different environmental soil samples collected in the vicinity of the phosphogypsum stack in Wiślinka (northern Poland) are presented and discussed in this paper. The (210)Po and (210)Pb concentrations in soil samples from the phosphogypsum stack recorded in this study are significantly higher only in areas that are close to the heap. The relationship between atmospheric deposition and elevated analyzed radionuclides concentrations in top soil layers, especially in the vicinity of the phosphogypsum stack, was showed in this study. (210)Po and (210)Pb radionuclides were detected in concentrations which could have harmful effects on human health or the environment. The considerably high concentrations of (210)Po and (210)Pb in soil samples collected from the vicinity of the phosphogypsum stack obtained in this study can lead to the conclusion that the presently undertaken recultivation process is successful and the 300 m(2) protection zone around the phosphogypsum stack seems to be able to offset the negative influence of the phosphogypsum stack on the surrounding environment.

Polonium (²¹⁰Po), uranium (²³⁴U, ²³⁸U) isotopes and trace metals in mosses from Sobieszewo Island, northern Poland

The activity of polonium (210)Po and uranium (234)U, (238)U radionuclides, as well as trace metals in mosses, collected from Sobieszewo Island area (northern Poland), were determined using the alpha spectrometry, AAS (atomic absorption spectrometry) and OES-ICP (atomic emission spectrometry with inductively coupled plasma). The concentrations of mercury (directly from the solid sample) were determined by the cold vapor technique of CV AAS. The obtained results revealed that the concentrations of (210)Po, (234)U, and (238)U in the two analyzed kinds of mosses: schrebers big red stem moss (Pleurozium schreberi) and broom moss (Dicranum scoparium) were similar. The higher polonium concentrations were found in broom moss (Dicranum scoparium), but uranium concentrations were relatively low for both species of analyzed mosses. Among the analyzed trace metals the highest concentration in mosses was recorded for iron, while the lowest for nickel, cadmium and mercury. The obtained studies showed that the sources of polonium and uranium isotopes, as well as trace metals in analyzed mosses are air city contaminations transported from Gdańsk and from existing in the vicinity the phosphogypsum waste heap in Wiślinka (near Gdańsk).

The radiochemical contamination (²¹⁰Po and ²³⁸U) of zone around phosphogypsum waste heap in Wiślinka (northern Poland)

The aim of this work was the determination of the impact of phosphogypsum waste heap in Wiślinka (northern Poland) for radiological protection of zone around waste heap. These studies are very important for the estimation of natural alpha radionuclides contents in the vicinity of phosphogypsum waste heap and for environmental pollution assessment of this area. The process of bioaccumulation of radionuclides in interior plants parts prove to examine their origin sources, too. The activity of (210)Po, (234)U, and (238)U were measured using an alpha spectrometer. The values of uranium and polonium concentration in water with immediate area of waste heap are considerably higher than in the waters of the Martwa Wisła river. The values of activity ratio (234)U/(238)U are approximately about one in the phosphogypsum (0.97 ± 0.05) and in the water of retention reservoir and pumping station (0.92 ± 0.01 and 0.99 ± 0.08), while in the water from the Martwa Wisła river they are slightly higher than one (1.03 ± 0.07 and 1.17 ± 0.06). In the analyzed plants species the highest amounts of polonium and uranium were found in ruderal plants samples (between 51 ± 1 and 89 ± 1 for (210)Po; between 36 ± 3 and 68 ± 3 for (238)U) as well as hygrophilous plant samples (18 ± 1 and 84 ± 3; 42 ± 2 and 130 ± 4, respectively for (210)Po and (238)U). The more amounts of (210)Po and (238)U radionuclides were accumulated mainly in the roots of plant species in comparison to green parts. The general conclusion of realized study is higher influence of phosphogypsum on radioactive contamination of environmental zone around heap waste in Wiślinka (northern Poland).