Contamination of settling ponds and rivers as a result of discharge of radium-bearing waters from Polish coal mines

Factors Contributing to Accumulation of 210Po in Freshwater Fishes in Dong Thai Lake, Vietnam and Radiological Hazard Assessment

210Po (polonium), one of the most toxic naturally occurring radionuclides, is well-known as a common natural radionuclide in fish species. Human consumption of 210Po-contaminated fish could result in a significant internal dose. This study determined by alpha spectrometry the 210Po activity in sixteen selected fish species with different living behaviors (pelagic, demersal), trophic positions (herbivores, carnivores, omnivorous), and masses in Dong Thai Lake, Hanoi, Vietnam. The min, max, and average of the 210Po concentration of sixteen fish species were 0.80 ± 0.44, 12.7 ± 0.20, and 3.54 ± 0.31 Bq kg-1, respectively. Regarding the different living behaviors, trophic positions, and masses, the results showed trending of 210Popelagic > 210Podemersal; 210Poherbivores < 210Pocarnivores < 210Poomnivorous and 210Po<0.2 kg > 210Po0.2-1 kg > 210Po>1 kg, respectively. The 210Po concentrations in muscle tissue were greater in fish species with a small mass, omnivorous trophic position, and pelagic living behavior relative to demersal fish with a larger mass that were herbivores or carnivores. In addition, the results showed an uneven distribution of 210Po activities in atmospheric aerosols, terrestrial soils, surface waters, and lake sediments in the study area. The primary source of 210Po could be supplied from atmospheric aerosols and/or terrestrial soils in the study area. The 210Po annual effective dose for adults due to fish consumption has been calculated with a range from 20 to 400 µSv y-1 and 111 µSv. y-1 on average, and it is far below the allowable limits of 1000 µSv y-1.

Influence of Dose Conversions, Equilibrium Factors, and Unattached Fractions on Radon Risk Assessment in Operating and Show Underground Mines

This paper compares the results of measurements taken in the underground workings of active and tourist mines. In these facilities, the aerosol size distributions of ambient aerosols at key workplaces and the distributions of radioactive aerosols containing radon decay products were determined. Based on these studies, dose conversions used for dose assessment and unattached fractions were determined. In addition, radon activity concentrations and potential alpha energy concentrations of short-lived progeny were also measured in the mines to determine the equilibrium factor. The dose conversions varied between 2-7 mSv/(mJ × h × m^-3). The unattached fraction measured in active coal mines ranged from 0.01-0.23, in tourist mines from 0.09-0.44, and in the tourist cave it was 0.43. The results showed significant discrepancies between the effective doses determined from current recommendations and legal regulations and those determined from direct measurements of parameters affecting exposure.

Pollution characteristics of soil heavy metals around two typical copper mining and beneficiation enterprises in Northwest China

In order to investigate the situation of heavy metal pollution in the heavy metal industry in Gansu Province, a large copper mining province, two large and typical copper mining and beneficiation enterprises with differences in topographic features, climatic conditions, and soil types were selected as the target of this study based on similar ore types and beneficiation processes. Around these two enterprises, geochemical baselines of the six heavy metals were established, while the degree of local soil heavy metal pollution and potential hazards to humans were assessed based on statistical analysis, single-factor and multi-factor index analysis, and health risk evaluation models. In addition, Spearman's correlation analysis and hierarchical cluster analysis were used to explore the intrinsic association between each heavy metal in the two mining industries to reveal the pattern of soil heavy metal pollution in the copper mining and beneficiation industry and to propose targeted measures to improve and prevent soil heavy metal pollution. The results showed that the heavy metal pollution in the soil around Shengxi Mining Co., Ltd. of Subei County (SX enterprise) was higher than that around Yangba Copper Co., Ltd. of Gansu Province (YB enterprise), but the two enterprises had similar patterns of pollution, with an overall medium level of pollution. The carcinogenic and non-carcinogenic risks for children and adults were within acceptable limits for both enterprises. Besides, the correlation between the different heavy metals to similarity in their sources of contamination and the different degrees of association between the soil heavy metals of the two enterprises due to their environmental characteristics.

Improvements in the radiochemical method for separating 226Ra in solid samples through coprecipitation with BaSO4

The aim of this work was to improve the commonly used method for ²²⁶Ra determination in water and to establish its application in solid samples. This method is based on the coprecipitation of Ra with BaSO₄ and gross alpha counting of the precipitate. An exhaustive study of the coprecipitation behaviour of the most abundant cations present in solid samples was performed to avoid incorrect radiochemical yields. As a result, it was considered necessary to introduce two new purification steps into the conventional method. Likewise, two nuclides, ²⁴¹Am and ²²⁶Ra, were compared to obtain the mass efficiency curve given their different behaviour in the coprecipitation process. While Ra behaves similarly to Ba, Am coprecipitates, forming mixed crystals that may behave differently in the self-absorption process. The influence of the cations on the chemical yield with no precipitate purification was: Sr²⁺≫Fe³⁺>Mg²⁺≈Ca²⁺>K⁺≈Na⁺. The method was successfully applied to soil, sediment, and plant ash samples.

A critical review on the occurrence and distribution of the uranium- and thorium-decay nuclides and their effect on the quality of groundwater

This critical review presents the key factors that control the occurrence of natural elements from the uranium- and thorium-decay series, also known as naturally occurring radioactive materials (NORM), including uranium, radium, radon, lead, polonium, and their isotopes in groundwater resources. Given their toxicity and radiation, elevated levels of these nuclides in drinking water pose human health risks, and therefore understanding the occurrence, sources, and factors that control the mobilization of these nuclides from aquifer rocks is critical for better groundwater management and human health protection. The concentrations of these nuclides in groundwater are a function of the groundwater residence time relative to the decay rates of the nuclides, as well as the net balance between nuclides mobilization (dissolution, desorption, recoil) and retention (adsorption, precipitation). This paper explores the factors that control this balance, including the relationships between the elemental chemistry (e.g., solubility and speciation), lithological and hydrogeological factors, groundwater geochemistry (e.g., redox state, pH, ionic strength, ion-pairs availability), and their combined effects and interactions. The various chemical properties of each of the nuclides results in different likelihoods for co-occurrence. For example, the primordial ²³⁸U, ²²²Rn, and, in cases of high colloid concentrations also ²¹⁰Po, are all more likely to be found in oxic groundwater. In contrast, in reducing aquifers, Ra nuclides, ²¹⁰Pb, and in absence of high colloid concentrations, ²¹⁰Po, are more mobile and frequently occur in groundwater. In highly permeable sandstone aquifers that lack sufficient adsorption sites, Ra is often enriched, even in low salinity and oxic groundwater. This paper also highlights the isotope distributions, including those of relatively long-lived nuclides (²³⁸U/²³⁵U) with abundances that depend on geochemical conditions (e.g., fractionation induced from redox processes), as well as shorter-lived nuclides (²³⁴U/²³⁸U, ²²⁸Ra/²²⁶Ra, ²²⁴Ra/²²⁸Ra, ²¹⁰Pb/²²²Rn, ²¹⁰Po/²¹⁰Pb) that are strongly influenced by physical (recoil), lithological, and geochemical factors. Special attention is paid in evaluating the ability to use these isotope variations to elucidate the sources of these nuclides in groundwater, mechanisms of their mobilization from the rock matrix (e.g., recoil, ion-exchange), and retention into secondary mineral phases and ion-exchange sites.

Pre-closure assessment of elevated arsenic and other potential environmental constraints to developing aquaculture and fisheries: The case of the Mae Moh mine and power plant, Lampang, Thailand

Our assessment of 30 water bodies in the vicinity of the Mae Moh coal mine and power station in northern Thailand does not indicate substantial water quality management challenges to developing fisheries/aquaculture in peripheral reservoirs and streams. Negative water quality issues such as high concentrations of arsenic (2-17 μg/L) and ions including sulfate (868-2605 mg/L), sodium (217-552 mg/L), and total ammonia (<1-5 mg/L) were associated with groundwater and surface water resources on the facility, as well as the stream network draining from it. Total dissolved solids were also very high, ranging from 658 to 3610 mg/L. Six of seven ponds tested had As concentrations in the range of 5-17 μg/L. Although these levels are less than the Thai regulation for industrial effluent, they are elevated over background surface water concentrations. The highest concentration in a contaminated stream was 10.54 μg/L As, which is only slightly above the WHO (2017) regulation of 10 μg/L for drinking water. Ponds, contaminated streams, and deep subsurface water should not be used for fisheries/aquaculture without extensive remediation/treatment. Concentrations of these water parameters in peripheral streams and reservoirs were not of environmental concern. High water hardness (161-397 mg/L CaCO₃ and potential ionic imbalances may be the greatest hindrances to developing sustainable fisheries and aquaculture in reservoirs in the study area. Routine monitoring of inorganic As species and other contaminants in water is needed to assess the full extent of arsenic risk at the site following closure.

Investigations on the application of different synthetic zeolites for radium removal from water

One possible method for removing radium from waters is to use zeolites. The research carried out and described in the article was aimed at examining a wide spectrum of zeolites: natural (clinoptilolite) and synthetic (NaP1, 13X, 3A, 5A), as some of them show the high efficiency of radium removal from all types of water, it means the drinking water and brines as well. Characteristic of zeolites, as the percentage of zeolite phase and other components, was performed by XRD analysis. For radium removal testing two samples of brines, collected from underground mine outflow, were used. Studies have confirmed, that the best efficiency of radium removal from mine water was found for the NaP1 type zeolite, produced on the base of fly ash with use of NaOH. Experiments showed that clinoptilolite, 3A, 5A and 13X have significantly lower efficiency of radium removal.

Long term behaviour of radium rich deposits in a lake ecosystem

Behaviour of radionuclides released into environment is crucial for further evaluation of any kind of possible effects. Possibility of observation how does a radionuclide behave in natural environment is limited to very few post accidental areas. However, valuable observation can be collected at areas where enhanced concentration of natural radionuclides is presented caused by activity of non-nuclear industry. One example is area affected by release of radium rich brines from coal mines (Upper Silesia, south of Poland) that let one observe radium and its decay product behaviour in freshwater ecosystem from long-term perspective. Selected as long-term observatory site former mine water reservoir allowed identification of processes leading to accumulation of radium in bottom sediments and observation of its further behaviour from 17-years-time perspective. New data were collected during two-years monitoring campaign and compared with archive data on radioactivity in water and sediments collected in 1999. Radium-barium co-precipitation process was identified as main source of sediments heavy contamination, however, radium chemical form resulted from this process is insoluble and not easy migrate to other environmental compartments, what was proved by low ²²⁶Ra and ²¹⁰Pb transfer to water measured under laboratory condition and to biota observed on site. As barium is not always present in mine radium rich brines a discussion is launched what would happen when such waters are released into environment based on simple laboratory experiment. In main conclusion is underlined that the current radium activity concentration in sediments is lower than expected only considering radioactive decay. Distribution of ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb in sediment profiles suggest that bio- or mechanical turbation (e.g. local flood) is responsible for significant ²²⁶Ra deficiency observed.

Testing of the radon tightness of beakers and different types of sealing used in gamma-ray spectrometry for 226Ra concentration determination in NORM

The presence of radium is common in the natural environment. However, some human activities lead to the production of large amounts of waste and by-product containing elevated concentrations of radium. Several methods for the determination of radium isotopes exist. The common use of gamma-ray spectrometry is justified by several of its advantages: it is a non-destructive method, easy, it is a time- and cost-effective procedure of preparing a sample and provides a reasonable time of measurement. The major disadvantages of direct measurements of radium are its weak yields γ-line 186.2 keV (3.59%) and, additionally, an interference with ²³⁵U direct line 185.7 keV. There is an indirect method of measuring radium. The method uses the daughter radionuclides of radon: ²¹⁴Pb and ²¹⁴Bi. The problem is radon escape from the measurement container. The article describes the tests of radontightness of various types of containers and different types of sealing. In frame of performed measurements, not sufficient tightness of typical containers used in laboratories was found.

Radioactivity in wastes generated from shale gas exploration and production - North-Eastern Poland

In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations were measured in 64 samples of wastes generated from shale gas exploration in North-Eastern Poland. The measured samples consist of drill cuttings, solid phase of waste drilling muds, fracking fluids, return fracking fluids and waste proppants. The measured activity concentrations in solid samples vary in a wide range from 116 to around 1100 Bq/kg for K-40, from 14 to 393 Bq/kg for U-238, from 15 to 415 Bq/kg for Ra-226, from 12 to 391 Bq/kg for Pb-210, from a few Bq/kg to 516 Bq/kg for Ra-228 and from a few Bq/kg to 515 Bq/kg for Th-228. Excluding the waste proppants, the measured activity concentrations in solid samples oscillate around their worldwide average values in soil. In the case of the waste proppants, the activity concentrations of radionuclides from uranium and thorium decay series are significantly elevated and equal to several hundreds of Bq/kg but it is connected with the mineralogical composition of proppants. The significant enhancement of Ra-226 and Ra-228 activity concentrations after fracking process was observed in the case of return fracking fluids, but the radium isotopes content in these fluids is comparable with that in waste waters from copper and coal mines in Poland.

NORM contaminated area identification using radionuclides activity concentration pattern in a soil profile

According to the requirements set by European BSS the exposure of humans and biota to ionizing radiation originating from natural radionuclides but under anthropogenically changed conditions should be managed within the same regulatory framework as other practices. Such situation creates the strong needs to have a reliable method to distinguish whether the particular case of natural radioactivity occurrence has resulted from human activity or it is pure natural phenomenon. In case of current activity of particular NORM industry there are no doubts however, in case of a legacy site, such question becomes crucial. One of the first warnings that the evaluated case has resulted from human deliberate or accidental activity is the lack of secular equilibrium among radionuclides constituting natural decay series. On the other hand some radionuclides, deposited on the ground surface due to radioactive fallout (e.g. caesium or lead isotope ²¹⁰Pb), create in long term perspective a specific pattern that remains characteristic for un undisturbed soil. Hence, it can be assumed that every observed change in it proves a human activity. In order to check this 19 soil profiles taken at undisturbed area and around different NORM heaps were analyzed. The measured radionuclides concentrations were used to anatomize any alternation of natural state, assess radionuclides migration and even investigate the history of a site of concern in the time horizon, usually long enough to identify any human activity. Results procured an easy method of identification different NORM sites based on observed ratios of particular natural radionuclides.

Long term changes in the concentration of radium in discharge waters of coal mines and Upper Silesian rivers

According to the latest guidelines of the International Atomic Energy Agency (IAEA, 2016), coal mining is one of the most important contributors to occupational exposure. Coal mining contributes about 45% of the total annual collective dose obtained by workers due to the exposure at places of working. One of the sources of exposure in mining are formation brines with elevated concentrations of natural radionuclides, the most common are radium ²²⁶Ra and ²²⁸Ra. Radium isotopes often occur in formation waters in underground collieries in the Upper Silesian region (USCB) in Poland. Significant amounts of radium remain underground in the form of radioactive deposits created as a result of spontaneous deposition or water treatment. This phenomenon leads to the increase of radiation hazard for miners. The remaining activities of ²²⁶Ra and ²²⁸Ra are released into the rivers with mine effluents, causing the contamination of bottom sediments and river banks. The results of radioactivity monitoring of effluents and river waters are presented here to illustrate a trend of long-term changes in environmental contamination, caused by mining industry in the Upper Silesian Region.

The self-absorption correction factors for 210Pb concentration in mining waste and influence on environmental radiation risk assessment

The radioactive lead isotope ²¹⁰Pb occurs in waste originating from metal smelting and refining industry, gas and oil extraction and sometimes from underground coal mines, which are deposited in natural environment very often. Radiation risk assessment requires accurate knowledge about the concentration of ²¹⁰Pb in such materials. Laboratory measurements seem to be the only reliable method applicable in environmental ²¹⁰Pb monitoring. One of the methods is gamma-ray spectrometry, which is a very fast and cost-effective method to determine ²¹⁰Pb concentration. On the other hand, the self-attenuation of gamma ray from ²¹⁰Pb (46.5 keV) in a sample is significant as it does not depend only on sample density but also on sample chemical composition (sample matrix). This phenomenon is responsible for the under-estimation of the ²¹⁰Pb activity concentration level often when gamma spectrometry is applied with no regard to relevant corrections. Finally, the corresponding radiation risk can be also improperly evaluated. Sixty samples of coal mining solid tailings (sediments created from underground mining water) were analysed. Slightly modified and adapted to the existing laboratory condition, a transmission method has been applied for the accurate measurement of ²¹⁰Pb concentration . The observed concentrations of ²¹⁰Pb range between 42.2 ÷ 11,700 Bq·kg^-1 of dry mass. Experimentally obtained correction factors related to a sample density and elemental composition range between 1.11 and 6.97. Neglecting this factor can cause a significant error or underestimations in radiological risk assessment. The obtained results have been used for environmental radiation risk assessment performed by use of the ERICA tool assuming exposure conditions typical for the final destination of such kind of waste.

Polonium-210 accumulates in a lake receiving coal mine discharges-anthropogenic or natural?

Coal is an integral part of global energy production; however, coal mining is associated with numerous environmental health impacts. It is well documented that coal-mine waste can contaminate the environment with naturally-occurring radionuclides from the uranium-238 (²³⁸U) decay series. However, the behavior of the final radionuclide in the ²³⁸U-series, i.e., polonium-210 (²¹⁰Po) arising from coal-mine waste-water discharge is largely unexplored. Here, results of a year-long (2014-2015) field study, in which the concentrations of ²¹⁰Po in sediments and surface water of a lake that receives coal-mine waste-water discharge in West Virginia are presented. Initial measurements identified levels of ²¹⁰Po in the lake sediments that were in excess of that which could be attributed to ambient U-series parent radionuclides; and were indicative of discharge site contamination of the lake ecosystem. However, control sediment obtained from a similar lake system in Iowa (an area with no coal mining or unconventional drilling) suggests that the levels of ²¹⁰Po in the lake are a natural phenomenon; and are likely unrelated to waste-water treatment discharges. Elevated levels of ²¹⁰Po have been reported in lake bottom sediments previously, yet very little information is available on the radioecological implications of ²¹⁰Po accumulation in lake bottom sediments. The findings of this study suggest that (Monthly Energy Review, 2016) the natural accumulation and retention of ²¹⁰Po in lake sediments may be a greater than previously considered (Chadwick et al., 2013) careful selection of control sites is important to prevent the inappropriate attribution of elevated levels of NORM in lake bottom ecosystems to industrial sources; and (Van Hook, 1979) further investigation of the source-terms and potential impacts on elevated ²¹⁰Po in lake-sediment ecosystems is warranted.

Levels of major and trace elements, including rare earth elements, and ²³⁸U in Croatian tap waters

Concentrations of 46 elements, including major, trace, and rare earth elements, and (238)U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and (238)U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including (238)U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters.

Mineral composition and heavy metal contamination of sediments originating from radium rich formation water

Radium rich formation water is often associated with fossil fuels as crude oil, natural gas and hard coal. As a result of fossil fuels exploitation high amount of such water is released into environment. In spite of the high radium content such waters create a serious radiation risk neither to humans nor biota directly. First and foremost due to very high mineralization they are not drinkable at all. But after discharge chemical and physical conditions are substantially changed and sediments which additionally concentrated radium are arising. Due to features of technological processes such phenomenon is very intensive in underground coal mining where huge volume of such water must be pumped into surface in order to keep underground galleries dry. Slightly different situation occurs in oil rigs, but finally also huge volume of so called process water is pumped into environment. Regardless their origin arising sediments often contain activity concentration of radium isotopes exceeding the clearance levels set for naturally occurring radioactive materials (NORM) (Council Directive, 2013). The analysis of metals and minerals content showed that besides radioactivity such sediments contain high amount of metals geochemically similar to radium as barium, strontium and lead. Correlation analysis proved that main mechanism leading to sediment creation is co-precipitation radium with these metals as a sulfate. The absorption on clay minerals is negligible even when barium is not present in significant quantities. Owing to very low solubility of sulfates radium accumulated in this way should not migrate into environment in the neighborhood of a site where such sediment were deposited.

Geno-toxicity assay of sediment and water samples from the Upper Silesia post-mining areas, Poland by means of Allium-test

Genotoxic potential of two environmental compartments (water and sediment) from the Upper Silesia Coal Basin (USCB), Poland were evaluated and compared by employing root meristem cells of Allium cepa. The clear genotoxic effect of water and sediment sampled was shown, with an important contribution of severe types of cytogenetic abnormalities. The most biologically relevant pollutants were revealed through multivariate statistical analysis of relationships between biological effects registered and the environment contamination. Overall, results of simultaneous use of conventional monitoring methods and biological tests suggested that contemporary levels of persistent pollutants in post-mining areas of the USCB may enhance the risk both for human health and biological components of natural ecosystems.

Evaluation of the impacts of mine drainage from a coal waste pile on the surrounding environment at Smolnica, southern Poland

Mine drainage impacts from a coal waste pile at Smolnica, Poland have been monitored. Groundwater in an unconfined aquifer downgradient from the pile has near-neutral pH, but high concentrations of sulfate (up to 3,827 mg/l), chloride (up to 903 mg/l), and sodium (up to 2,606 mg/l). Concentrations of iron and manganese are elevated only locally, and concentrations of other metals are low. The behavior of sulfate seems to be conservative in the downgradient aquifer, and gypsum may only be precipitating locally. Concentrations of iron and manganese seem to be controlled by the precipitation of ferric oxide and hydroxides and rhodochrosite, respectively. Complete neutralization of mine drainage by carbonates is consistent with high concentrations of calcium (up to 470 mg/l) and magnesium (up to 563 mg/l) and also with high strontium concentrations of up to 3.08 mg/l, observed in groundwater downgradient from the pile. Hydraulic head profiles at two sites within the river bottom sediments indicate upward flow toward the river with large local differences in groundwater recharge. Water chemistry profiles in the river bottom sediments and geochemical modeling suggest conservative behavior of Na, Cl, and SO(4) and precipitation of Fe and Mn at the groundwater/river water interface. Mine drainage enters the Bierawka River and causes increasing sulfate concentrations. In contrast, concentrations of sodium and chloride in the Bierawka River decrease downgradient from the pile because water in the river upgradient from the pile is already highly contaminated by these species from the discharge of mining waters. Concentrations of Fe and Mn in the river water are low, as a consequence of the precipitation of Fe and Mn oxide and hydroxides. Direct geochemical modeling was able to reproduce measured concentrations of conservative species (e.g., Na, Cl, and SO(4)), but errors for metals and Ba were relatively large. In addition, calculated P(CO2) values in the river water are very high, suggesting that equilibrium with atmospheric P(CO2) and P(O2) has not been reached, and at least some reactions should be modeled as kinetic processes. High concentrations of Na, Cl, and SO(4) contribute to the contamination of the Odra River, which is joined by the Bierawka River farther downgradient, thus limiting the use of river water for recreation and other purposes.

Leaching of technologically enhanced naturally occurring radioactive materials

A form of waste associated with mining activities is related to the type of deposit being mined and to the procedure of exploitation and enrichment adopted. The wastes usually contain relatively large amounts of technologically enhanced naturally occurring radioactive materials (TENORM). The TENORM are often stored on the surface. Consequently, they can be leached as a result of interaction with aqueous solutions of different chemical composition. This further leads to pollution of water and soil in the vicinity of the stored wastes. The paper presents the results of laboratory investigation aimed at quantifying the leaching process of samples originating from uranium dumps and storage reservoirs associated with brine pumped from coal mines. The leaching process was investigated with respect to selected elements: uranium isotopes, radium isotopes, iron, barium and sodium. The samples were exposed to aqueous solutions of different chemical composition. The experiments revealed that TENORM in form of sulphate compounds are the most resistant against leaching. The leaching coefficient for radium isotopes varies from a few thousandth percent to a few hundredth percent. On the other hand, for TENORM occurring in sand or sludge, the leaching coefficient for uranium and radium isotopes ranged from a few hundredth percent to a few percent.

Availability of radium isotopes and heavy metals from scales and tailings of Polish hard coal mining

Radium and heavy metal contaminated tailings and scales resulting from Polish hard coal mining were investigated for their mobilisation potential by using leaching methods. The main focus is set on a three-step extraction procedure proposed by BCR (Bureau Communautaire de Référence, now Standards Measurements and Testing Programme) of the European Union, which was used for investigating the availability of radium isotopes. In addition, the results of a Polish extraction procedure for the heavy metals' water solubility are presented for rough comparison. After a special treatment, the BCR-reagents were measured by gamma-spectrometry to define their radium activity concentrations; the heavy metal content in the water soluble fractions was determined by ICP-AES. The samples were collected at two different sites influenced by the discharge of pit water from hard coal mining. The tailings were taken from a former tailing pond, which now is no longer in use, but the settled material is still present. At another abandoned and meanwhile flooded tailing pond, the scales were scraped from the inside of a discharge tube. The results obtained show that there is different leaching behaviour between the radium isotopes. The tailings being characterised by surface adsorbed radium provide up to 25% of the initial (226)Ra content, (228)Ra is altogether leached up to 15%. The scales comprise stable radiobaryte (Ba[Ra]SO(4)) and can be considered as being unable to provide radium isotopes, since no trace of radium dissolution was observed. The leaching behaviour of heavy metals is similar to that of radium. Mn, Ni and Zn are dissolved by water from the tailings; the scales do not provide any.

Effects on non-human species inhabiting areas with enhanced level of natural radioactivity in the north of Russia: a review

Results of long-term radioecological investigations in areas with an enhanced level of natural radioactivity in the north of Russia are summarized. Deleterious changes within animal and plant populations inhabiting areas with an enhanced level of natural radioactivity in the Komi Republic were revealed. These changes are expressed in enhanced levels of mutagenesis, destructive processes in the tissues of animals, disturbances of reproductive functions and reduced offspring viability. Compensatory processes, resulting in animal and plant survival under extremely adverse conditions of radium and uranium-radium contamination, were observed as well. However, obvious signs of adaptation failed to be detected. The findings suggest that adverse somatic and genetic effects are possible in plants and animals in the dose range observed at sites with an enhanced level of natural radioactivity. In contrast, different plant species inhabiting an area with an enhanced level of natural radioactivity in the taiga zone of the Sakha Republic (Yakutia) reveal a stimulation of growth processes, photosynthesis, endogenous low molecular weight antioxidant synthesis as well as adaptive response. It is apparent from the data presented that naturally occurring differences in terrestrial radiation level could be of genetic and ecological consequence.