Accumulation Of Radium Research Articles

Radium uptake by earthworms E. fetida after exposure to contaminated soil

Radium-226 is one of the most important radionuclides for assessing the radiation exposure in terrestrial ecosystems in terms of its significant contribution to the internal and total dose rates. A laboratory culture of Eisenia fetida was exposed to soil contaminated with 226Ra and 238U during two months. These nuclides entered the soil as a result of industrial radium production (Vodny, Komi Republic, Russia). The concentrations of 226Ra and 238U were 89000 ± 9000 and 2130 ± 270 Bq kg−1 of soil. Bioaccumulation of 226Ra was investigated in E. fetida exposed to the radioactive soil or to a mixture containing the same radioactive soil diluted with peat and sand. The activity concentrations of 226Ra in E. fetida were higher after exposure to the contaminated soil compared to the mixture. The literature data on the radium accumulation in earthworms were considered also. Our experiments showed that the concentration ratio (CR) of 226Ra in E. fetida varied from 5.5 × 10−4 to 4.5 × 10−3 Bq kg−1 f.w./Bq kg−1 d.w. The average CRs were (6.7 ± 1.7) × 10−4 for the earthworms E. fetida from the soil mixture and (3.2 ± 1.2) × 10−3 for those from the radioactive soil. These CRs for 226Ra were up to two orders of magnitude lower than the values calculated by us from the results obtained by other researchers for natural earthworm populations in areas with lower levels radioactivity.

Long-term accumulation of 226Ra in some agricultural soils based on model assessment

Groundwater and inorganic fertilizers are regularly applied to agricultural soils, but their 226Ra content is potentially hazardous to human health and the environment. Due to irrigation and fertilization processes, 226Ra can accumulate in topsoils, and might also leach to subsoils, groundwater, and surface water. However, there are few studies on the accumulation of radium in the agricultural soils due to irrigation with groundwater. In this work, we analysed the radium content in 60 groundwater samples collected from a coastal area of Phu Yen Province, Vietnam where groundwater is regularly used for irrigation practices. Long-term accumulation of 226Ra in agricultural topsoils due to irrigation with groundwater was modelled for rice, maize, potato, and tomato topsoils. The fate of 226Ra in the topsoil (0–20 cm) was studied by using the Canadian Environmental Modelling Centre (CEMC) soil model and the HYDRUS-1D model. We found that the total inputs of 226Ra were 0.83, 2.45, 0.24, and 0.57 Bq m−2 d−1 for rice, maize, potato, and tomato soils, respectively. The total removals were 0.145, 0.236, 0.272, and 0.125 Bq m−2 d-1 found in rice, maize, potato, and tomato soils, respectively. A simple formula was developed to calculate the accumulation rate of 226Ra in the topsoil. Using this model we predict that the activity concentration of 226Ra will increase in rice, maize, and tomato soil, but will remain almost unchanged in potato soils. The accumulation rates 226Ra were 224, 791, and 115 Bq m−2 y−1. After 25 years of agricultural practices, the total activity values of 226Ra that accumulate in rice, maize, and tomato soils can reach 5147, 17278, and 2711 Bq m−2, respectively. We found the good agreements in the results based on two models. The irrigation practices with groundwater samples contribute 96.7, 79.5, and 79.8 % of 226Ra to the accumulation rates of 226Ra in rice, maize, and tomato soils, respectively.

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.

Removal of radium in a working drinking water treatment plant: Radiological hazard assessment and waste management.

Occurrence of radium in drinking water may pose a radiological hazard. It is one of the most radiotoxic radionuclides and a major contributor to the Indicative Dose (ID), regulated parameter in UE. Its removal at Drinking Water Treatment Plants (DWTPs) can be considered a preventive action, as it cannot reach the final consumer nor be accumulated in distribution pipes. A filtration system based on greensand designed for radium removal was tested in an actual DWTP. Removal effectiveness depended on the spatial velocity water passed through the filter, range 65-100%. The lower the spatial velocity, the greater contact time, and the longer high removal percentages were achieved. The radium removed from the water was mainly associated to easily reducible fraction in greensand. So radium accumulation in the filter may pose a radiological hazard for the workers in the DWTP. Dose rate was assessed in the worst case scenario for this case study, being about 0.22 mSv/y, significantly lower than reference value 1 mSv/y. Radium accumulated in the greensand filter can be extracted in order to ease waste management, and subsequently, the filtration system can be regenerated showing similar capacity to extract radium as a new one.

Emerging investigator series: radium accumulation in carbonate river sediments at oil and gas produced water discharges: implications for beneficial use as disposal management.

In the western U.S., produced water from oil and gas wells discharged to surface water augments downstream supplies used for irrigation and livestock watering. Here we investigate six permitted discharges on three neighboring tributary systems in Wyoming. During 2013-16, we evaluated radium activities of the permitted discharges and the potential for radium accumulation in associated stream sediments. Radium activities of the sediments at the points of discharge ranged from approximately 200-3600 Bq kg-1 with elevated activities above the background of 74 Bq kg-1 over 30 km downstream of one permitted discharge. Sediment as deep as 30 cm near the point of discharge had radium activities elevated above background. X-ray diffraction and targeted sequential extraction of radium in sediments indicate that radium is likely coprecipitated with carbonate and, to a lesser extent, sulfate minerals. PHREEQC modeling predicts radium coprecipitation with aragonite and barite, but over-estimates the latter compared to observations of downstream sediment, where carbonate predominates. Mass-balance calculations indicate over 3 billion Bq of radium activity (226Ra + 228Ra) is discharged each year from five of the discharges, combined, with only 5 percent of the annual load retained in stream sediments within 100 m of the effluent discharges; the remaining 95 percent of the radium is transported farther downstream as sediment-associated and aqueous species.

Multiple environmental factors influence 238U, 232Th and 226Ra bioaccumulation in arbuscular mycorrhizal-associated plants

Ecological consequences of low-dose radioactivity from natural sources or radioactive waste are important to understand but knowledge gaps still remain. In particular, the soil transfer and bioaccumulation of radionuclides into plant roots is poorly studied. Furthermore, better knowledge of arbuscular mycorrhizal (AM) fungi association may help understand the complexities of radionuclide bioaccumulation within the rhizosphere. Plant bioaccumulation of uranium, thorium and radium was demonstrated at two field sites, where plant tissue concentrations reached up to 46.93 μg g−1 238U, 0.67 μg g−1 232Th and 18.27 kBq kg−1 226Ra. High root retention of uranium was consistent in all plant species studied. In contrast, most plants showed greater bioaccumulation of thorium and radium into above-ground tissues. The influence of specific soil parameters on root radionuclide bioaccumulation was examined. Total organic carbon significantly explained the variation in root uranium concentration, while other soil factors including copper concentration, magnesium concentration and pH significantly correlated with root concentrations of uranium, radium and thorium, respectively. All four orders of Glomeromycota were associated with root samples from both sites and all plant species studied showed varying association with AM fungi, ranging from zero to >60% root colonisation by fungal arbuscules. Previous laboratory studies using single plant-fungal species association had found a positive role of AM fungi in root uranium transfer, but no significant correlation between the amount of fungal infection and root uranium content in the field samples was found here. However, there was a significant negative correlation between AM fungal infection and radium accumulation. This study is the first to examine the role of AM fungi in radionuclide soil-plant transfer at a community level within the natural environment. We conclude that biotic factors alongside various abiotic factors influence the soil-plant transfer of radionuclides and future mechanistic studies are needed to explain these interactions in more detail.

Geochemistry of radioactive elements in bituminous sands and sandstones of Permian bitumen deposits of Tatarstan (east of the Russian plate)

The article investigates geochemical features of Permian (Cisuralian, Ufimian Stage and Biarmian, Kazanian Stage of the General Stratigraphic Scale of Russia) bituminous sands and sandstones located on the territory of the Volga-Ural oil and gas province (Republic of Tatarstan). Natural bitumens are extracted using thermal methods as deposits of high-viscosity oils. In the samples studied, the specific activity of natural radionuclides from the 238U (226Ra), 232Th, and 40K series was measured using gamma spectrometry. As a result of the precipitation of uranium and thorium and their subsequent decay, the accumulation of radium (226Ra and 228Ra) has been shown to occur in the bituminous substance. In the process of exploitation of bitumen-bearing rock deposits (as an oil fields) radium in the composition of a water-oil mixture can be extracted to the surface or deposited on sulfate barriers, while being concentrated on the walls of pipes and other equipment. This process requires increased attention to monitoring and inspection the environmental safety of the exploitation procedure.

Sources of Radium Accumulation in Stream Sediments near Disposal Sites in Pennsylvania: Implications for Disposal of Conventional Oil and Gas Wastewater.

In Pennsylvania, Appalachian oil and gas wastewaters (OGW) are permitted for release to surface waters after some treatment by centralized waste treatment (CWT) facilities. While this practice was largely discontinued in 2011 for unconventional Marcellus OGW at facilities permitted to release high salinity effluents, it continues for conventional OGW. This study aimed to evaluate the environmental implications of the policy allowing the disposal of conventional OGW. We collected stream sediments from three disposal sites receiving treated OGW between 2014 and 2017 and measured 228Ra, 226Ra, and their decay products, 228Th and 210Pb, respectively. We consistently found elevated activities of 228Ra and 226Ra in stream sediments in the vicinity of the outfall (total Ra = 90-25,000 Bq/kg) compared to upstream sediments (20-80 Bq/kg). In 2015 and 2017, 228Th/228Ra activity ratios in sediments from two disposal sites were relatively low (0.2-0.7), indicating that a portion of the Ra has accumulated in the sediments in recent (<3) years, when no unconventional Marcellus OGW was reportedly discharged. 228Ra/226Ra activity ratios were also higher than what would be expected solely from disposal of low 228Ra/226Ra Marcellus OGW. Based on these variations, we concluded that recent disposal of treated conventional OGW is the source of high Ra in stream sediments at CWT facility disposal sites. Consequently, policies pertaining to the disposal of only unconventional fluids are not adequate in preventing radioactive contamination in sediments at disposal sites, and the permission to release treated Ra-rich conventional OGW through CWT facilities should be reconsidered.

Long-term monitoring of water treatment technology designed for radium removal—removal efficiencies and NORM formation

A drinking water treatment plant in Viimsi, Estonia, was monitored over three years for iron, manganese, radium-226, radium-228, as well as their daughter nuclides, in order to determine the efficiency of the treatment process, gain an insight into the removal mechanisms and interactions between radium, iron, and manganese, and assess the overall longevity and performance of the technology along with the possible build-up of NORM in the treatment process. During the study, samples were collected from raw water, first and second stage filtrate, consumer water, backwash water and filter materials. The results show consistent removal efficiency for iron and manganese, as well as an average of over 85% removal for radium with a slight decline over time. The backwash process has been optimised for maximum radium removal from the filters, while keeping concentrations in the backwash water below exemption levels. However, the accumulation of radium and thorium occurs in the filter material, exceeding exemption levels in the top layer of the filter columns in less than a year. By the end of the observation period, activity concentrations in the top layer of the columns were above 30 000 Bq kg−1 for Ra-226 and Ra-228, and around 15 000 Bq kg−1 for Th-228. Radionuclides are not homogenously distributed in the filter columns. In order to estimate the average activity concentrations in the filter media, the height distribution of radionuclides has to be accounted for. Two years and two months after commissioning the treatment plant, the average activity concentrations of Ra isotopes in the filter columns were in the range 10 000 Bq kg−1, while Th-228 activity concentration was roughly 3500 Bq kg−1.

Age Dating Oil and Gas Wastewater Spills Using Radium Isotopes and Their Decay Products in Impacted Soil and Sediment

Spills from oil and gas operations can contaminate water resources, sediment, and soil, but in many cases, information about spill sources and environmental impacts is not available. Here we present age dating methods to estimate the time since the accumulation of radium in impacted soils and sediments from oil and gas wastewater spills. The retention of unsupported 226Ra and 228Ra from spill water to soil and sediment and the ingrowth of Ra progeny result in three independent age dating methods using the 228Th/228Ra, 210Pb/226Ra, and 228Ra/226Ra activity ratios. We tested the 228Th/228Ra method on spill sites in North Dakota and West Virginia, where the dates of the spills are known. The 228Th/228Ra method yields ages similar to the documented spill ages and can reveal the initial 228Ra/226Ra ratios of the spill waters, validating the notion that Ra isotopes and their decay products in contaminated soils and sediments can reveal the ages and origins of spills.

NORM in the East Midlands' oil and gas producing region of the UK

Naturally occurring radioactive material (NORM) is a common feature in North Sea oil and gas production offshore but, to date, has been reported from only one production site onshore in the United Kingdom. The latter, Wytch Farm on the Dorset coast, revealed high activity concentrations of 210Pb in metallic form but little evidence of radium accumulation. NORM has now been discovered at two further onshore sites in the East Midlands region of the UK. The material has been characterized in terms of its mineralogy, bulk composition and disequilibrium in the natural uranium and thorium series decay chains. In contrast to Wytch Farm, scale and sludge samples from the East Midlands were found to contain elevated levels of radium and radioactive progeny associated with crystalline strontiobarite. The highest 226Ra and 228Ra activity concentrations found in scale samples were 132 and 60 Bq/g, with mean values of 86 and 40 Bq/g respectively; somewhat higher than the mean for the North Sea and well above national exemption levels for landfill disposal. The two East Midlands sites exhibited similar levels of radioactivity. Scanning electron microscope imaging shows the presence of tabular, idiomorphic and acicular strontiobarite crystals with elemental mapping confirming that barium and strontium are co-located throughout the scale. Bulk compositional data show a corresponding correlation between barium-strontium concentrations and radium activity. Scales and sludge were dated using the 226Ra/210Pb method giving mean ages of 2.2 and 3.7 years, respectively. The results demonstrate clearly that these NORM deposits, with significant radium activity, can form over a very short period of time. Although the production sites studied here are involved in conventional oil recovery, the findings have direct relevance should hydraulic fracturing for shale gas be pursued in the East Midlands oilfield.

Radium in Bulgarian coals

Abstract The radium content of 14 Bulgarian coal deposits has been determined and its geochemical behavior is discussed and compared with that of uranium and thorium. The radium content varies greatly, from 0.1 to 3.1 parts per trillion (ppt) in individual samples. In several deposits it is 1.2 to 4.4 times higher than the supposed coal Clarke value, which is 0.7 ppt (Yudovich and Ketris, 2006). The deposits comprise lignites, subbituminous, bituminous, and anthracite coals. No relation of the Ra content to rank was established. The radium content usually varies significantly between the mines and seams of individual deposits. In some vertical seam sections Ra and U are enriched in the bottom part of the seam. The accumulation and distribution of Ra were found to be dependent on factors such as: (a) source provinces comprising granites and metagranitoids that favor the accumulation of radium, (b) location of the deposits in uranium-bearing formations, (c) hydrological conditions of the area and the mines; water may act both as a carrier of the elements and as a dissolving agent, and (d) tectonic structure of the deposit and processes of sedimentation. Complicated tectonic regions favor the input of Ra, or by contrast Ra leaching and redistribution. The Ra/U ratio for most deposits is lower than the supposed values for brown (2.4 × 10 − 7 ), and hard (3.7.10 − 7 ) coals. Radium in the coals is of mixed organic and inorganic association, based on the correlations between radium and ash yield, thorium and uranium.

Accumulation of radium in relation to some chemical analogues in Dicranopteris linearis

This study elucidates the uptake and accumulation of radium in the field-growing fern Dicranopteris linearis by relating the radium concentration to some potential chemical analogues, including alkaline earth metals, rare earth elements, and some important heavy metals. Time-dependent accumulation of radium and these chemical analogues for D. linearis were described by the (228)Th/(228)Ra activity ratio, an index for inferring plant age. The correlation between radium and these elements was assessed by statistical analysis and used as a reference to elucidate the uptake and accumulation of radium in relation to the chemical analogues. Analytical and statistical results showed that the concentrations of alkaline earth metals (except for Mg) rare earth elements and some heavy metals in D. linearis increased linearly with plant age. These elements, exhibiting a similar accumulation pattern to radium and significant correlation coefficients with radium, were considered as the chemical analogues to radium. Additionally, the plant/soil concentration ratios (CRs) for radium and most of these analogues in D. linearis exceeded 1, consistent with the definition of hyper-accumulator plants.

Accumulation of radium in ferruginous protein bodies formed in lung tissue: association of resulting radiation hotspots with malignant mesothelioma and other malignancies

While exposure to fibers and particles has been proposed to be associated with several different lung malignancies including mesothelioma, the mechanism for the carcinogenesis is not fully understood. Along with mineralogical observation, we have analyzed forty-four major and trace elements in extracted asbestos bodies (fibers and proteins attached to them) with coexisting fiber-free ferruginous protein bodies from extirpative lungs of individuals with malignant mesothelioma. These observations together with patients’ characteristics suggest that inhaled iron-rich asbestos fibers and dust particles, and excess iron deposited by continuous cigarette smoking would induce ferruginous protein body formation resulting in ferritin aggregates in lung tissue. Chemical analysis of ferruginous protein bodies extracted from lung tissues reveals anomalously high concentrations of radioactive radium, reaching millions of times higher concentration than that of seawater. Continuous and prolonged internal exposure to hotspot ionizing radiation from radium and its daughter nuclides could cause strong and frequent DNA damage in lung tissue, initiate different types of tumour cells, including malignant mesothelioma cells, and may cause cancers.

Radium accumulation by plants

Radium accumulation by plants

The role of Typha sp. in affecting the radium behavior in the water column of a salt coastal lagoon

The radium accumulation and releasing in Typha Domingenes Pers. foliage in a coastal lagoon was studied by in situ and lab experiments. From leaf sample analysis and lab experiments, adsorption experiments followed by procedure sequential extraction, it was observed the importance of the ionic exchange for the foliar accumulation. The higher the salinity, the lower the accumulation in leaves. Decomposition of leaves was studied by litterbag methods during a period of 6 months. At the end of the experiments the major cation losses were 99% of K, 76% of Na and 51% of Mg. On the other hand the amount of Ca in the residue increased seven times as well as increased the total activity of 226 Ra and of 228 Ra (seven and at least three times, respectively). In agreement with this observation, laboratory experiments showed that the material was able to adsorb quite a 100% of the added Ra and its adsorption capacity was estimated at 5 meq (Ba2+ )/gdetritus . Radionuclide releasing by sequential extraction of the detritus material followed a little bit different dynamic from the green leaves, showing that important fraction of the radium can be retained in the litter by humidified material.

Compton suppression gamma-spectroscopy in the analysis of radium and lead isotopes in ocean sediments

Compton suppression gamma-spectroscopy provides an efficient method for measuring the concentration of226Ra,228Ra, and210Pb in ocean sediments. The background reduction realized from the suppressed mode of operation provides an “active shield” to allow for the low-level counting required for these measurements. We have used the method to study the possible accumulation of radium from produced waters in sediments from Gulf of Mexico sites of varied distances from drill platforms. In addition,210Pb levels were determined to evaluate the use of our spectrometer for this purpose. Baseline undisturbed concentrations have been obtained from the study of subsurface core material which predates drilling activities. Correlations of radium isotope concentrations with iron and barium provide information concerning the possible relationships between radium levels and drilling activity (excess barium) and natural variations in sediment texture (iron).

A study of radium uptake by the water-lily Nymphaea violacea (Lehm) from contaminated sediment

The rate and extent of radium-226 accumulation from sediment by the water-lily Nymphaea violacea (Lehm) were assessed. The plants were collected from Magela Creek, Northern Territory, Australia and grown in 226RaCl 2-labelled laboratory sediment over a period of 570 days. The nominal sediment activity of 5 Bq g −1 dry weight was ∼100 times that of the naturally occurring concentration. In the roots and rhizomes, 226Ra accumulated on plant surfaces. This result was confirmed by autoradiographic studies which showed the presence of an iron-containing plaque on the surface of these tissues with which the radium was closely associated. Little radium reached the pith of the rhizomes and acropetal translocation was not detected. The average concentration ratio for growing rhizomes was 0·22. Assuming first order accumulation kinetics and likely incremental environmental concentrations, this Aboriginal dietary tissue could become dose-limiting within 50 years. The foliar accumulation of radium originating from the sediment was predominately due to contamination via the sediment-water-plant pathway. Differences in foliar radium concentrations in plants of different ages were due to differential biomass turnover rates. Plants with faster biomass turnover had higher average radium concentrations.

Principal coordinate analysis of the distribution of radium-226 between water, sediment and the waterlily, Nymphaea violacea (Lehm), in the vicinity of a uranium mine in the Northern Territory, Australia

Radium-226 concentrations in water, sediment and Nymphaea violacea (Lehm) root and rhizome samples were strongly correlated over 2 years between three sample sites from Magela Creek, Northern Territory, Australia. The uptake by roots and rhizomes was due primarily to surface accumulation. Radium-226 concentrations in foliage were not correlated with media concentrations. However, foliar tissue senescence was shown to increase radium accumulation across a range of aquatic plant species including N. violacea ( P < 0·05). Principal coordinate analysis showed that the distribution of radium and calcium concentrations in the foliar organs of N. violacea were strongly correlated ( r = 0·522; P < 0·001). This result supported the hypothesis that radium was accumulated and/or distributed by the mechanisms involved in uptake of the nutrient divalent cation. However, subsequent analyses comparing the ratio of extractable radium and calcium in the supporting media to their ratio in the plant showed no correlation, which suggested that different uptake mechanisms were involved.

Radium accumulation from water by foliage of the water lily, Nymphaea violacea

Radium accumulation from water by foliage of the water lily, <i>Nymphaea violacea</i>