Cultivation of the macrophyte Lemna minor and the microalgae Chlorella sorokiniana in thermal mineral waters: Biomass characteristics, radioisotopes and heavy metals content.

Microalgae and macrophytes are commonly used as human and animal food supplements. We examined the cultivation of the microalgae Chlorella sorokiniana and the duckweed Lemna minor in thermal waters under batch and sequencing batch conditions and we characterized the produced biomass for the presence of essential nutrients as well as for heavy metals and radioisotope content. The highest specific growth rate for the microalgae was observed when 5 or 15 mg/L N were supplemented while the optimal conditions for Lemna minor were observed in the co-presence of 5 mg/L N and 1.7 mg/L P. Lemna minor presented higher concentrations of proteins and lipids comparing to the studied microalgae. Both organisms contained high amounts of lutein (up to 1378 mg/kg for Lemna minor) and chlorophyll (up to 1518 mg/kg for Lemna minor) while ß-carotene and tocopherols were found at lower concentrations, not exceeding a few tens of mg/kg. The heavy metal content varied between the two species. Lemna minor accumulated more Cd, Cu, K, Mn, Na, Ni, and Zn whereas Al, Ca and Mg were higher in Chlorella sorokiniana. Both organisms could be a significant source of essential metals but the occasional exceedance of the statutory levels of toxic metals in food products raises concern for potential risk to either humans or animals. Application of gamma-spectroscopy to quantify the effective dose to humans from 228Ra, 226Ra and 40K showed that Chlorella sorokiniana was well under the radiological limits while the collected mass of Lemna minor was too small for radiological measurements with confidence.

Natural radioactivity of residues from groundwater treatment facilities in Finland.

The accumulation of naturally occurring radionuclides in solid residues was investigated from groundwater treatment facilities (GTFs) in Finland. Natural radionuclides U-238, Ra-226, Pb-210 and Ra-228 were found in various precipitates, sludges and filters at concentrations exceeding the general clearance level of 1 kBq kg-1used for solid materials in the European directive 2013/59/Euratom. The accumulation of natural radionuclides in different solid residues was observed even when the activity concentrations in the untreated groundwater were relatively low, and when there was no measurable change in the concentrations between raw and treated groundwater within analytical uncertainties. Based on mass and activity balance considerations this is thought to be due to the large volumes of treated water per year. The exposure of workers to natural radiation from solid residues in the regular use of a groundwater facility was found not to be likely to exceed 0.3 mSv a-1if the activity concentrations are <10 kBq kg-1for U-238, Ra-226, Pb-210 and Ra-228. The worker exposure from solid residues is therefore likely to remain below the reference level of 1 mSv a-1, and indoor radon is more of a concern for the radiation protection of workers at GTFs. However, the natural radionuclide content in the different solid residues from groundwater treatment needs to be characterised properly to be able to ensure safety in the final use of the residues with respect to the potential exposure of the public.

Evaluation of radioactivity levels and radiological hazards of some endemic plants used as medicine in Ankara, Turkey.

In this study, natural radioactivity levels (226Ra, 232Th, and 4 K) of some medicinal plant samples with known anti-oxidative properties, which are frequently consumed by animals and humans, were obtained from Ankara province and its surroundings (Mamak, Kizilcahamam, Beypazari, Kahramankazan, and Polatli districts) were determined using a thallium-doped sodium iodide NaI(Tl) gamma spectrometry. By using the determined natural radioactivity concentrations in the collected plant samples, the number of radiological doses that people could be exposed by consuming these plants was calculated. As a result of the study, 226Ra, 232Th, and 4 K radioactivity concentration ranges of the plant samples were found be 14.69 ± 1.27-59.08 ± 3.12 Bq kg-1, 1.78 ± 0.04-50.05 ± 2.76 Bq kg-1 and 207.24 ± 34.09-826.13 ± 25.40 Bq kg-1, respectively. The highest 226Ra, 232Th, and 4 K activity concentrations were measured in Astragalus densifolius subsp. ayashensis (Kahramankazan), Astragalus kochakii (Kahramankazan) and Rumex patientia (Patience Dock) (Kahramankazan) plants, respectively. The lowest 226Ra, 232Th and,4 K activity concentration plants were determined respectively as Rumex patientia (Mamak), Lavandula angustifolia (Kizilcahamam), and Astragalus acikirensis (Polatli). The establishment and routine repetition of environmental radioactivity monitoring programs in each region are important for human and animal health, and the results of this study gain importance for Ankara and its surroundings in terms of environmental health.

Natural radioactivity of groundwater in Vendian deposits in St. Petersburg Region.

The study is focused on the hydrogeological conditions and the chemistry of groundwater of the Vendian aquifer in the western part of the Leningrad oblast (Karelian Isthmus and the area near Sosnovy Bor town) and St. Petersburg City, where groundwater features higher radioactivity, but nevertheless it is used for drinking water supply. Data on the radiological characteristics, which have been determined in the estimation of the quality of groundwater used for drinking are generalized and analyzed. These characteristics include the gross alpha and gross beta activity and the specific activity of natural radionuclides 222Rn, 226Ra, 228Ra, 210Pb, 210Po, 238U, and 234U. The data were subjected to statistical and correlation analysis to determine the hygienic criteria for the use of groundwater of this aquifer for drinking water supply and to study the sources and the processes of formation of the natural radiological background. Groundwater quality standards were shown to be exceeded in the majority of the analyzed wells. The brackish water in the southern, deeper, part of the aquifer system was shown to have higher radioactivity and relatively high concentrations of 226Ra, 228Ra, 210Pb, and 210Po, compared with fresh water in the northern part of the territory, of which higher, though nonuniform, 222Rn activity is typical. Relationships between the radiation characteristics of groundwater are considered along with the causes of formation of groundwater radionuclide composition as a result of the higher radioactivity of the host deposits and the chemistry of groundwater; changes in the radiological and hydrochemical background groundwater characteristics from the north to the south are characterized in accordance with the subsidence of the aquifer system and an increase in the stagnation of the hydrochemical regime. The analysis of the well-known relationship between the concentrations of radium isotopes in groundwater, uranium and thorium isotopes in the host rocks, and groundwater residence time in the aquifer, along with the comparison of the available field data with calculation results, suggested the conclusion that the concentration of uranium in the water-bearing rocks in the major portion of the area under consideration is higher than its regional mean values.

Targeted education and outreach to neighbors of homes with high gross alpha radioactivity in domestic well water.

Gross alpha, a measurement of radioactivity in drinking water, is the most frequent laboratory test to exceed primary drinking water standards among wells tested under the New Jersey Private Well Testing Act (NJ PWTA). Certain geological factors prevalent in New Jersey (NJ) are primarily responsible for the presence of radioactivity in private well drinking water and thus, many of the estimated one million private well users in NJ may be at-risk of water contamination from naturally occurring radionuclides. Neighbor-based private well outreach methodology was utilized to identify high risk wells in both northern and southern NJ regions and offer free private well testing for radionuclides. Previously tested wells with gross alpha exceeding or equal to 3.7 becquerels per liter (Bq L-1; 100 pCi/L) were selected (n = 49) to identify neighbors (n = 406) within 152.4 m (500 feet). Invitation letters were mailed to selected neighbors and some of the previously tested high wells (n = 12) offering free water sampling for the following parameters: gross alpha (48-hour rapid test), combined radium-226 and radium-228 (Ra-226 + Ra-228), uranium-238 (U-238), radon-222 (Rn-222) and iron. Overall, 70 neighbors and 5 high PWTA wells participated in this free water testing opportunity. For neighboring wells, gross alpha results revealed 47 (67.1%) wells exceeding the gross alpha MCL of 0.555 Bq L-1 (15 pCi/L) mainly due to radium activity in the raw/untreated water. Of those with water treatment (n = 62), 12 (19.4%) treated water samples exceeded the gross alpha MCL. Targeting neighbors of known highly radioactive wells for private well testing is an effective public health outreach method and can also provide useful insight of regional contaminant variations.

Does exposure to weathered coal ash with an enhanced content of uranium-series radionuclides affect flora? Changes in the physiological indicators of five referent plant species.

Coal ash deposited in open landfills is a potential source of environmental pollutants due to the contained toxic element content. The weathered coal ash used in this study additionally contains enhanced activity concentrations of 238U series radionuclides. This study aimed to determine the physiological effects of enhanced ionizing radiation and toxic elements on five plant species (smilo grass, sticky fleabane, blackberry, mastic and pine tree) inhabiting the coal ash disposal site. Among the potentially toxic measured elements, contents of Sb, As and especially V significantly exceeded their respective levels at the control site, as well as the content of 238U and its progenies. Significant changes in photosynthetic pigments were recorded following chronic exposure to the plants growing on the coal ash site. Different responses were also observed in the plant species regarding the activity of catalase and glutathione-S-transferase (GST). The level of lipid peroxidation markedly increased in plants from the disposal site, except in blackberry, wherein GST activity was the strongest, indicating an important role of that enzyme in the adaptation to coal ash pollutants. The results of this study suggest that the modulation of the studied biochemical parameters in plants growing on coal ash is primarily species-dependent.

Seasonal variations of terrestrial gamma dose, natural radionuclides and human health.

The aim of the research was to study seasonal variations in gamma radiation and the statistical significance of these variations. Moreover, we compared in-situ and laboratory analyses of uranium, thorium, radium and potassium K-40 contents. Exposure to a low level of radiation is a minor (but still is) contributor to overall cancer risk therefore we compared doses generated by gamma radiation with overall cancer risk. The research was performed in SW Poland in two granitoid massifs -Strzelin and Karkonosze. The in-situ measurements were performed seasonally using gamma-ray spectrometer Exploranium with BGO detector and Radiometer RK-100. The laboratory measurements were performed using spectrometer with HPGe detector Canberra-Packard and alpha spectrometry technique. The general trend of seasonal variations of natural radionuclides, terrestrial ambient gamma dose (TGDR) and ambient gamma dose rate (AGDR) was difficult to identify. We noticed slightly increased values of all analysed parameters in warmer seasons, and lower in colder, although there were some exceptions. These exceptions were induced by precipitation and varied soil water content, but variations were mostly not statistically significant. The statistically important deviation from the trend was registered only in equivalent uranium data when the survey was carried out during or just after intensive precipitation. We observed a good positive correlation between in-situ and laboratory results (TGDR in situ/Lab r = 0.696), therefore, we recommend using in-situ measurements in a dense measuring grid before collecting selected soil samples to better evaluate the level of natural radiation in the environment. The average ambient gamma dose in the Karkonosze Massif was 0.52 mSv y-1 whereas in the Strzelin Massif was 0.39 mSv y-1. The overall cancer risk in Karkonoski county is higher than in Strzelin county. A connection between increased gamma radiation and higher overall cancer risk is possible but should be examined during more elaborated research.

Estimation of radiological impact of the activities of Olusosun Dump Site on workers and dwellers of Olusosun, in Lagos Southwest Nigeria.

This study assessed the potential radiological risks associated with the activities on Olusosun dump site on workers and dwellers of Olusosun community. The activity concentrations of 238U, 232Th and 40K from of soil and water samples were determined using High-Purity Germanium (HPGe) detector. The background radiation level of Olusosun dump site was measured using a portable Geiger-Müller counter-Radeye B20 survey meter. The mean value of background radiation was 1.46 mSv/yr. This value is about 46% higher than the recommended reference level of 1.0 mSv/yr for the public. The mean activity concentrations of 238U, 232Th and 40K in the soil samples were 19.1 ± 3.2, 29.1 ± 4.4 and 171.5 ± 6.1 Bq/kg respectively which are about 45.4%, 35.3% and 59.2% lower than the world's average levels. For the water samples, the mean activity concentrations obtained for 238U, 232Th and 40K are 0.4 ± 0.4, 0.8 ± 0.2 and 0.8 ± 0.3 Bq/l respectively. These are about 99.9% and 20% lower than WHO reference levels for 238U and 232Th. The mean absorbed dose rate in air (D), Annual effective dose (AED) outdoor, Radium Equivalent (Req), External hazard index (Hex) internal hazard index (Hin) and Excess lifetime cancer risk (ELCR) from soil samples were 33.6 nGy/h, 41.0 µSv/yr, 73.1 Bq/kg and 0.2, 0.3 and $1.4\times{10}^{-4}$, respectively. Absorbed dose in air D, AED outdoor, Req, Hex, Hin and ELCR are 41.1%, 41.4%, 80.3%, 80%, 75% and 50% lower than their corresponding world's average and references. The estimated AEDw from ingestion of water is 148.9 ± 50.4 µSv/yr, this is about 49% higher than the WHO reference level of 100.0 µSv/y from ingestion of water. The radiological hazard indices estimated from soil samples do not indicate any potential risks to the users. The elevated background radiation level of the dump site, and AEDw from ingestion of water, however, suggest that the activities on Olusosun dump site pose potential radiological risks on workers on the site and the public from consumption of water from Olusosun community.

Distribution of Radionuclides and Radiological Health Assessment in Seih-Sidri Area, Southwestern Sinai.

The current contribution goal is to measure the distribution of the radionuclide within the exposed rock units of southwestern Sinai, Seih-Sidri area, and assess the radiological risk. Gneisses, older granites, younger gabbro, younger granites, and post granitic dikes (pegmatites) are the main rock units copout in the target area. Radioactivity, as well as radiological implications, were investigated for forty-three samples from gneisses (seven hornblende biotite gneiss and seven biotite gneiss), older granites (fourteen samples), and younger granites (fifteen samples of syenogranites) using NaI (Tl) scintillation detector. External and internal hazard index (Hex, Hin), internal and external level indices (Iα, Iγ), absorbed dose rates in the air (D), the annual effective dose equivalent (AED), radium equivalent activity (Raeq), annual gonadal dose (AGDE), excess lifetime cancer risk (ELCR), and the value of Upper Continental Core 232Th/238U mass fractions were determined from the obtained values of 238U, 232Th and 40K for the examined rocks of Seih-Sidri area. The average 238U mg/kg in hornblende biotite gneiss and biotite gneiss, older granites, and syenogranites is 2.3, 2.1, 2.7, and 8.4 mg/kg, respectively, reflecting a relatively higher concentration of uranium content in syenogranites. The results suggest that using these materials may pose risks to one's radiological health.

Determination of the internal dose due to the intake of 226Ra and 210Pb in drinking water from deep wells in the Metropolitan Region of Recife-Brazil.

The Metropolitan Region of Recife, the capital of the state of Pernambuco in northeastern Brazil, has a high demographic density and developed under a region of marine phosphorus with high concentrations of phosphate that naturally contains uranium ore, producing ionizing radiation from descendants of the radioisotope 238U where 226Ra and 210Pb are of great importance in verifying the probable harmful effects on human health due to environmental radioactivity. The supply of drinking water is the responsibility of the state-owned company COMPESA which uses wells of great depth to complete the supply of drinking water for the entire population. COMPESA and the RAE Group of the Federal University of Pernambuco developed a joint project to assess the concentrations of 226Ra and 210Pb and estimate the equivalent and effective doses caused by ingesting these radiation sources. According to the above, this research aimed to evaluate concentrations of 226Ra and 210Pb in drinking water samples from 110 deep wells in Recife. The activities of 226Ra and 210Pb ranged from 1.4 ± 0.3 to 119.3 ± 12.9 and from 25.6 ± 3.3 to 563.2 ± 45.6 mBq.L-1, with arithmetic means of 48.1 ± 3.8 and 231.1 ± 20 mBq.L-1, respectively. The equivalent doses average in bone tissue due to 226Ra and 210Pb were 0.45 ± 0.04 and 3.9 ± 0.37 mSv.y-1, and the annual average effective doses were 0.01 ± 0.00 and 0.13 ± 0.01 mSv.y-1, respectively.

Case studies of radioactivity of drilling mud for in situ leaching uranium mining in China.

The drilling mud from in situ leaching uranium mining is a type of low-radioactivity waste that contains natural nuclides and other harmful substances. In order to determine whether the drilling mud can meet the requirements of radioactive exemption management standards, field investigations and data simulations were conducted in this study. Two typical uranium mines were selected for onsite investigations. Drilling mud from different layers (i.e., the upper covering layer and ore-bearing layer) and from different stages (e.g., logging stage mud, drilling expansion stage mud, and mixed mud) was sampled. For each sample, the 238U and 226Ra concentrations of the solid components and the U and 226Ra concentrations of the supernatant were analyzed. The results revealed that the highest 238U and 226Ra concentrations of the solid components were 4122 Bq/kg and 4077 Bq/kg, while the 238U and 226Ra concentrations of the mixed drilling mud were all less than 300 Bq/kg. A radioactivity estimation model was established for scenario analysis. Exemption management screening lines of waste drilling mud, which can be used to classify and treat the drilling project according to the deposit's grade and conditions, were proposed for in situ leaching drilling projects.

Impact of Environmental Radiation on the Incidence of Cancer and Birth Defects in Regions with High Natural Radioactivity.

Four regions of high natural radioactivity were selected to assess radionuclide levels in rocks and soils, ambient radiation doses, radon exhalation from the ground, and radon concentrations in the air. The regions have different geochemical characteristics and radioactivity levels, which modulate the radiation exposure of local populations. Combining radiometric data with data from regional health statistics on non-infectious diseases, a statistically significant positive correlation was found between radiation exposure and the incidence of cancer and birth defects. Although this is a preliminary and prospective study, the empirical evidence gathered in this paper indicated increased the incidence of some diseases in relationship with the natural radiation background. It is suggested that further research, including epidemiological studies and direct determination of radiation exposures in regions with a high natural radiation background, is needed and justified.

Environmental evaluation of radioactivity levels and associated radiation hazards in groundwater around the WIPP site.

Groundwater may contain radioactive substances which can be dangerous to human health. Concentrations of natural radionuclides polonium (Po), thorium (Th), uranium (U), and radium (Ra) isotopes were measured in groundwater samples collected from different locations in the vicinity of the Waste Isolation Pilot Plant (WIPP) site in Carlsbad, New Mexico. The average values of gross activity concentrations of 210Po, 228Th, 238U, 234U, 226Ra and 228 Ra isotopes were determined to be 1.62 Bq L-1 in shallow groundwater and 5.88 Bq L-1 in deep groundwater, respectively. The total radioactivity in deep groundwater was higher than that in shallow groundwater, and most of the radioactivity in the water is from 226Ra. Furthermore, the effective doses for ingestion of natural radionuclides were about 0.333 mSv y-1 for shallow groundwater and about 1.338 mSv y-1 for deep groundwater samples, which are higher than the World Health Organization (WHO, 2017) guideline level (0.1 mSv y-1) for drinking water. Ra dominated the total ingestion dose, contributing 93.06 % and 75.40 % of the total effective doses to the deep and shallow groundwater, respectively. The ingrowth and decay of natural radionuclides suggested that 228Ra/226Ra ratio can be a useful indicator of the source of radioactive contamination. The radioactivity data obtained from the investigated groundwater samples can be used to establish a baseline for radioactivity levels in groundwater around the WIPP site.

Risk survey for the population of Recife and neighboring cities due to the occurrence of radium in groundwater.

The Metropolitan Region of Recife and its surroundings are heavily exploited to capture water for public supply through tubular wells. However, a survey of the levels of natural radionuclides from these sources had never been carried out, even though part of this region contains a phosphate deposit that has a high concentration of natural uranium. In this context, this research aimed to identify 228Ra and 226Ra levels in groundwater in the coastal region of Pernambuco, Brazil. About 110 points (wells) of drinking water for public supply were identified and studies were carried out to estimate the level of ingestion and subsequent risk due to the presence of this radionuclide. The average concentration of combined radium was 104 mBq.L-1. For 228Ra an effective dose of 0.46, 0.11, 0.12 and 0.0276 mSv.y-1 for infants, children aged 1 and 10 and adults, respectively, were obtained. Although doses above those recommended by WHO were found, the equivalent dose and the induction of bone sarcoma did not indicate a risk to the population. Groundwater with higher dose values is influenced by local geology.

Radioactivity in Future Phosphogypsum: New predictions based on estimates of 'Peak P' and rock phosphate resources.

Global food supplies currently depend on producing inorganic P fertilisers from a finite reserve of rock phosphate (RP). P fertilisers are themselves significant pollutants but their production from RP also leaves a phosphogypsum (PG) by-product that is sufficiently radioactive that its reuse is restricted. PG is mostly accumulated in open 'stacks' that make up a significant proportion of all Technologically Enhanced Naturally-Occurring Radioactive Material (TENORM) waste. Using lower and upper estimates of current RP reserves, historic production, and Hubbert's logistic function-based 'peak theory', lower and upper boundaries for possible RP production were predicted to the year 2100. The 'low' boundary scenario had a production peak of c.350 Mt/a RP in c.2050 followed by a steep decline. The 'high' boundary scenario had a production peak of c.1200 Mt/a RP in about 2090. Future trends in P demand for food production were used to predict a possible, demand-driven, RP production scenario until 2100 which peaked at a demand of c.620 Mt/a RP and was within possible production boundaries. An RP:P ratio of 5.62:1 and PG:P fertiliser ratio of 4:1 was used to calculate that this predicted demand-driven scenario would ultimately produce nearly 350 Mt/a of PG and a cumulative total of c.30 Gt by 2100. Average PG activity concentrations of 226Ra (650 Bq/kg), 210Po (300 Bq/kg) and 230Th (100 Bq/kg) give a total of c.30 PBq radioactivity in this by-product. Humanity is faced with a phosphorus dilemma - if the low production scenario unfolds it threatens food security but if predicted demand for P is met from RP the environmental challenges arising from P fertiliser use will be profound and exacerbated by a significant radioactive waste challenge. The estimates reported here show that studies of environmental radioactivity have a role to play in debates about P resources and global food security.

Multifractal features of activity concentration and stochastic risk assessment of naturally occurring and technogenic radionuclides in the soil of Yerevan, Armenia.

Spatial patterns and background ranges of naturally occurring radionuclides (NORs) (i.e. U-238, Th-232, K-40) and Cs-137 were studied in the urban soils of Yerevan, the capital city of Armenia. Multifractal Inverse Distance Weighting (MIDW) was used to generate and analyze distribution patterns of radionuclide activities. Based on Fourier transformation of radioactivity data, a spectral analysis was also applied to separate, where possible, background/baseline patterns from local anomalies: two ranges of background values were found to characterise the Yerevan territory. Specifically, in the south and south-east of Yerevan, the lower background ranges of U-238, Th-232 and K-40 comprised in the intervals 2.60-36.42 Bq/kg, 4.04-30.63 Bq/kg and 147.7-396.7 Bq/kg, respectively, were observed in association with the presence of sedimentary formations. In contrast, the higher ones were found, instead, in the central and northern parts of the city where andesite-basalt lavas and ignimbrite tuffs occur. Here, the background values rise to 142.4 Bq/kg, 138.76 Bq/kg and 1502 Bq/kg, respectively. As for the distribution of artificial Cs-137, its baseline levels in Yerevan seem to depend mostly on the global radioactive fallout and some local technogenic sources. Its distribution patterns partially differ from those of NORs. In the framework of this paper, Radium equivalent activity (RaEq), outdoor absorbed dose rate in air (ODRA) and annual effective dose equivalent (AEDEs) were also determined and mapped. They show a good coincidence of their spatial variations with those of NORs. The Monte Carlo simulation was used to assess excess lifetime cancer risk from a stochastic perspective. The related sensitivity analysis revealed that, among NORs, U-238 and Th-232 give the greatest contribution to the total variance (45.7% 42.8%, respectively). In comparison, K-40 has the lowest share (11.3%). Regarding Cs-137, a highly negligible contribution to the onset of health risks (accounting for 0.02%) was observed.

Determination of radioactivity levels in feldspathic dental ceramics.

Activity concentrations of 42 different feldspathic dental ceramic powders were determined using a gamma spectrometer with an HPGe detector. The average 238U, 232Th and 226Ra activity concentrations of the specimens were 126 ± 8 Bq kg-1, 5.6 ± 0.5 Bq kg-1 and 12.7 ± 1.2 Bq kg-1, respectively. The average 40K activity was found as 2855 ± 89 Bq kg-1 ranging from 2252 ± 70 Bq kg-1 to 3522 ± 110 Bq kg-1 due to high potassium content in dental ceramics. None of the activity concentration measurements exceeded the limits by EC and ISO.

Radioactive fossils: The uranium anomaly and its paleobiological implications.

In this study, several natural radionuclides (40K, 238U, 235U, 228Ac) and their decay product were investigated in various invertebrate and vertebrate fossils. In the high radioactivity group of fossils, 238U and 235U concentrations increased from 141 to 3621 Bq/kg and from 5.4 to 167 Bq/kg, respectively. In the low radioactivity group of fossils, concentrations of both U isotopes increased from 4.6 to 51 Bq/kg and from 0.18 to 2.3 Bq/kg, respectively. High radioactivity has been linked to the phosphatization process that affected the uranium sorption. Scanning of electron microscope images and X-ray fluorescence analysis were used to confirm the mode of preservation of studied fossils and the presence of a correlation between the phosphorus content and uranium elements in fossil specimens.

Evaluation of naturally occurring radioactive materials (NORM) in the soil, in a potential area for unconventional reservoirs in the Rancheria Sub-Basin.

Naturally occurring radioactive elements depend on lithology geogenic characteristics, such as depositional, environmental, or diagenetic. Thus, evaluating these elements constitutes a tool to define ionizing radiation effect from rocky sequences. This study carried out in the Rancheria Sub-Basin establishes both characterization and assessment of this kind of material, known as NORM. The sampling included uranium-238, thorium-232, potassium-40, radon-226, and radon-222 in soil samples, cutting samples from the Molino-1 well, and radon in surface water. Bases on a radiometric methodology with a gamma-ray spectrometer for uranium-238, thorium-232, and potassium-40 and emanometric with ionizing chambers for radio-226 and radon-222. The analysis and results of the activity concentrations in soil samples of U-238, Th-232, K-40, and Ra-226 are 11.7 BqKg-1, 33.0 BqKg-1, 424.5 BqKg-1, and 15.59 BqKg-1, respectively, among the acceptable global averages. However, in some areas, observed values indicate high activity concentrations of U-238, Th-232, K-40, Ra-226, and Rn-222 in the soil of 50.2 BqKg-1, 62.8 BqKg-1, 1596.3 BqKg-1, 44.25 BqKg-1, and 112546.79 Bqm-3, respectively. Those activity concentrations were associated with zone lithology.

Phosphogypsum and its potential use in Croatia: challenges and opportunities.

Phosphogypsum (PG) is a waste by-product (residue) originating from the production of phosphoric acid and phosphate fertilisers. PG contains chemical and radioactive impurities, which is why it is mostly stockpiled in controlled areas. Worldwide, only about 15 % of PG is recycled or reused. Today, policies and business strategies prioritise sustainable development through circular economy, which certainly includes PG. This provides new opportunities for Croatia to manage its PG and make an effort to use it as an additive in different industries, such as agriculture and construction. Due to its chemical and radiological properties, PG can potentially cause problems for the environment and human health. Hence, before using PG, detailed knowledge of potential hazards is necessary to protect people and the environment. The aim of this review is to summarise available data on Croatian PG, compare them with other countries, and to identify knowledge gaps and the lack of data on potential hazardous substances in PG in order to assess the opportunities of using PG in Croatia.