Distribution, risk evaluation, and source allocation of cesium and strontium in surface soil in a mining city.

Radioactive nuclides cesium (Cs) and strontium (Sr) possess long half-lives, with 135Cs at approximately 2.3 million years and 87Sr at about 49 billion years. Their persistent accumulation can result in long-lasting radioactive contamination of soil ecosystems. This study employed geo-accumulation index (Igeo), pollution load index (PLI), potential ecological risk index (PEPI), health risk assessment model (HRA), and Monte Carlo simulation to evaluate the pollution and health risks of Cs and Sr in the surface soil of different functional areas in a typical mining city in China. Positive matrix factorization (PMF) model was used to elucidate the potential sources of Cs and Sr and the respective contribution rates of natural and anthropogenic sources. The findings indicate that soils in the mining area exhibited significantly higher levels of Cs and Sr pollution compared to smelting factory area, agricultural area, and urban residential area. Strontium did not pose a potential ecological risk in any studied functional area. The non-carcinogenic health risk of Sr to the human body in the study area was relatively low. Because of the lack of parameters for Cs, the potential ecological and human health risks of Cs was not calculated. The primary source of Cs in the soil was identified as the parent material from which the soil developed, while Sr mainly originated from associated contamination caused by mining activities. This research provides data for the control of Cs and Sr pollution in the surface soil of mining city.

The character of Lake Kishkensor contamination in the area of underground nuclear explosions at the Semipalatinsk Test Site territory.

The timely identification of areas where man-made radionuclides migrate through water streams is highly important for the territory of the former Semipalatinsk Test Site since the aquatic environment is currently a source of secondary contamination of environment. This article presents research findings on radioactively contaminated Lake Kishkensor located at the Semipalatinsk Test Site territory. As a result of this research, a new locally contaminated spot was discovered in the vicinity of the "Balapan" test site. Lake Kishkensor was found to be contaminated with man-made 3H and 90Sr. The 3H activity concentration in surface waters reached 430 kBq/L, and the concentration of 90Sr reached 100 Bq/L. In the sediments, the 3H activity concentration reached 700 kBq/kg, while that of 90Sr and 239+240Pu reached 310 Bq/kg and 250 Bq/kg, respectively. Ground water was found to be a source of surface water and sediment contamination. The monitoring results showed that the contamination level of the lake largely depended on the season and the inflow of contaminated ground water.

[Assessment of the radiation risk to health caused by the intake of Cs-137 and Sr-90 radionuclides from food in the able-bodied population of the Samara region].

Monitoring of the content of technogenic radionuclides (Cs-137 and Sr-90) in foods is one of the key areas in ensuring radiation safety of the population, taking into account the current radiation situation. The greatest risk to health is food produced or imported from the territories that have been subjected to man-made radiation accidents. The purpose of the research was to assess the radiation risk caused by oral intake of radionuclides based on the study of the actual nutrition of the adult population and contamination of food with Cs-137 and Sr-90 radionuclides. Material and methods. The specific activity of Cs-137 and Sr-90 radionuclides (median and 90 percentile) was assessed by gamma spectrometric method in 1235 samples of food produced in the Samara region and imported from outside. Data on the actual nutrition of 894 respondents aged 18 to 68 years (in the autumn-winter period) were obtained by the 24-hour dietary recall using the automated software package Nutri-prof (version 2.9). Based on the data obtained, effective annual doses of internal radiation were calculated, information was obtained on the risks of malignant neoplasms, including in the long-term period under various scenarios of internal radiation. Results. Radiometric studies of food samples did not reveal deviations from hygienic standards. The highest median values of Cs-137 specific activity were observed in samples of forest mushrooms (1.23 Bq/kg), wild berries (0.97 Bq/kg), fish and fish products (0.96 Bq/kg). The highest median values of Sr-90 specific activity were also observed in samples of forest mushrooms (3.86 Bq/kg), fish and fish products (2.71 Bq/kg). The radiation risk under various scenarios of Cs-137 intake was regarded as «negligible¼, while the risk was regarded as «small¼ when consuming food contaminated with Sr-90. The number of additional cases of malignant neoplasms at the admission of Cs-137 in the median values of specific activity is 0.38 per year, at maximum values - 0.57 per year, at the admission of Sr-90 - 2.04 per year and 3.30 cases per year, respectively. Conclusion. The implementation of radiation monitoring of food, especially those imported from areas of high radiation risk, is a necessary condition for ensuring radiation safety of the population. It is also necessary to take into account the stochastic effect of the influence of small doses of internal exposure on the organism when consuming food, which make a significant contribution to the formation of the dose of internal radiation.

Fish otoliths as biological dosimeter: internal dose calculation.

Otoliths are organs used by fish for hearing and keeping balance. They consist of biogenic crystals of hydroxyapatite and do not contain any living cells. Upon exposure to ionizing radiation, otolith hydroxyapatite accumulates radiation-induced stable CO2- radicals whose amount is proportional to absorbed dose. In electron paramagnetic resonance (EPR) dosimetry, carbonate ions are registered and, hence, the total accumulated dose in the fish otolith can be quantified. Therefore, otoliths can be used as individual fish dosimeters to support radiobiological and radioecological studies. An important aspect of otolith-based EPR dosimetry on fish from contaminated water bodies is the potential presence of bone-seeking 90Sr. Consequently, cumulative absorbed doses measured with EPR in otoliths may reflect the superposition of internal exposure to 90Sr/90Y and external exposure due to radionuclides circulating in soft tissue of the fish as well as due to environmental contamination. The objective of the present study was to develop a method that allows for an assessment of the contribution of 90Sr to the total dose in otolith. The method has been tested using otoliths from seven fish taken from reservoirs located in the Southern Urals contaminated with radionuclides including 90Sr. It has been shown that dose to otoliths is largely determined by 90Sr in the hydroxyapatite. The internal dose component can be calculated using activity concentration-to-dose conversion factors, which vary slightly in the range of 2.0-2.8 × 10-3 Gy year-1 per Bq g-1 depending on fish species and age. Internal doses to fish from water bodies with different levels of 90Sr contamination were calculated in the range from 2 mGy to ~ 200 Gy. External dose contribution was derived for two fish only to be about 100 and 40 Gy. It is concluded that EPR dosimetry on fish otoliths is a promising tool when external exposure prevails or is comparable to internal exposure due to 90Sr.

Measurement of 90Sr in Marine Biological Samples.

Strontium-90 (90Sr) is one of the most hazardous radionuclides, and it contributes to radiation exposure by ingestion. The routine determination of 90Sr in marine biological samples is highly desirable given the development of the nuclear power industry. A fast, simple, and low-detection-limit method was developed for the measurement of 90Sr in marine biological samples based on determining 90Y by means of coprecipitation and solvent extraction with bis-2-ethylhexyl-phosphoric acid (HDEHP) in n-heptane. The interfering 210Bi is removed using Bi2S3 precipitation. The separation and purification of eight samples per day can be accomplished through this method. The detection limit of 90Sr for this method is 0.10 Bq/kg (ash weight). The radiochemical procedure was validated by fitting the decay curve of the sample source and by the determination of 90Sr standards.

Recent Development on Determination of Low-Level 90Sr in Environmental and Biological Samples: A Review.

In the context of the rapid development of the world's nuclear power industry, it is vital to establish reliable and efficient radioanalytical methods to support sound environment and food radioactivity monitoring programs and a cost-effective waste management strategy. As one of the most import fission products generated during human nuclear activities, 90Sr has been widely determined based on different analytical techniques for routine radioactivity monitoring, emergency preparedness and radioactive waste management. Herein, we summarize and critically review analytical methods developed over the last few decades for the determination of 90Sr in environmental and biological samples. Approaches applied in different steps of the analysis including sample preparation, chemical separation and detection are systematically discussed. The recent development of modern materials for 90Sr concentration and advanced instruments for rapid 90Sr measurement are also addressed.

Analytical Methods for the Determination of 90Sr and 239,240Pu in Environmental Samples.

Artificial long-lived radionuclides such as 90Sr and 239,240Pu have been long released into the environment by human nuclear activities, which have a profound impact on the ecological environment. It is of great significance to monitor the concentration of these radionuclides for environmental safety. This paper summarizes and critically discusses the separation and measurement methods for ultra-trace determination of 90Sr, 239Pu, and 240Pu in the environment. After selecting the measurement method, it is necessary to consider the decontamination of the interference from matrix elements and the key elements, and this involves the choice of the separation method. Measurement methods include both radiometric methods and non-radiometric methods. Radiometric methods, including alpha spectroscopy, liquid scintillation spectrometry, etc., are commonly used methods for measuring 239+240Pu and 90Sr. Mass spectrometry, as the representative of non-radiometric measurement methods, has been regarded as the most promising analytical method due to its high absolute sensitivity, low detection limit, and relatively short sample-analysis time. Through the comparison of various measurement methods, the future development trend of radionuclide measurement is prospected in this review. The fully automatic and rapid analysis method is a highlight. The new mass spectrometer with ultra-high sensitivity shows strong analytical capabilities for extremely low concentrations of 90Sr, 239Pu, and 240Pu, and it is expected to develop determination methods with higher sensitivity and lower detection limit.

RESULTS OF RESEARCH OF PERSONAL HYGIENE PRODUCTS FOR SUITABILITY FOR SPECIAL PROCESSING IN ZONES OF CHEMICAL, RADIOACTIVE CONTAMINATION AND IN COMBAT CONDITIONS.

OBJECTIVE: The aim: Research of personal hygiene products with detoxification properties by evaluating their formulation composition, emulsifying and complexing ability to heavy metal ions and radionuclides. PATIENTS AND METHODS: Materials and methods: The complex-forming ability of raw materials with heavy metal ions was determined in vitro, the content of heavy metals was determined by the method of atomic emission spectrometry with inductively coupled plasma (BS EN 13805:2014); determined the content of 137Cs, 232Th, 40K, 226Ra, 90Sr in washings from the surface of the skin of hands treated with personal hygiene products. The means were tested for compliance with the standard on scintillation spectrometers of gamma radiation energy «SEG-001¼ «AKP-S¼ and beta radiation (SEB-01-70); methods used: MI 12-04-099 and MI 12-05-099. RESULTS: Results: A high complexing ability of the pectin-containing «Liana¼ shampoo was found in relation to heavy metal ions (Co2+, Cu2+, Zn2+, Cd2+, Pb2+), as well as in their combined presence. It was established that the effectiveness of removing fatty impurities from the surface of the skin of the «Liana¼ product was 10.1 times higher than that of liquid soap (p<0.001). A high level of deactivating, degassing and antibacterialproperties of the personal care products «Bastion¼ and «Bastion-M¼ was revealed. CONCLUSION: Conclusions: Today, there is significant potential in the creation of formulations for special (sanitary) skin and hair surface treatment, containing natural complexing agents as detoxicants, and can be used in special professional activities associated with the risk of exposure to CBRN factors.

Earliest isotopic evidence in the Maya region for animal management and long-distance trade at the site of Ceibal, Guatemala.

This study uses a multiisotope (carbon, nitrogen, oxygen, and strontium) approach to examine early animal management in the Maya region. An analysis of faunal specimens across almost 2,000 years (1000 BC to AD 950) at the site of Ceibal, Guatemala, reveals the earliest evidence for live-traded dogs and possible captive-reared taxa in the Americas. These animals may have been procured for ceremonial functions based on their location in the monumental site core, suggesting that animal management and trade began in the Maya area to promote special events, activities that were critical in the development of state society. Isotopic evidence for animal captivity at Ceibal reveals that animal management played a greater role in Maya communities than previously believed.

Modern Flow Analysis.

A brief overview of articles published in this Special Issue of Molecules titled "Modern Flow Analysis" is provided. In addition to cross-sectional and methodological works, there are some reports on new technical and instrumental achievements. It has been shown that all these papers create a good picture of contemporary flow analysis, revealing the most current trends and problems in this branch of flow chemistry.

An Automated SeaFAST ICP-DRC-MS Method for the Determination of 90Sr in Spent Nuclear Fuel Leachates.

To reduce uncertainties in determining the source term and evolving condition of spent nuclear fuel is fundamental to the safety assessment. ß-emitting nuclides pose a challenging task for reliable, quantitative determination because both radiometric and mass spectrometric methodologies require prior chemical purification for the removal of interfering activity and isobars, respectively. A method for the determination of 90Sr at trace levels in nuclear spent fuel leachate samples without sophisticated and time-consuming procedures has been established. The analytical approach uses a commercially available automated pre-concentration device (SeaFAST) coupled to an ICP-DRC-MS. The method shows good performances with regard to reproducibility, precision, and LOD reducing the total time of analysis for each sample to 12.5 min. The comparison between the developed method and the classical radiochemical method shows a good agreement when taking into account the associated uncertainties.

Radiation monitoring of agricultural soils of the Volyn region in Ukraine.

Background: The development of effective environmental management programs requires an appropriate assessment of the current state of the environment and contributes to anticipating future changes in the state of the environment. Obtaining such information is one of the main objectives of monitoring the environment, which is subject to anthropogenic stress, including radiological contamination. The distribution of radionuclides and their ability to migrate in ecological chains and concentration in individual parts requires special control in contaminated areas. Objective: The purpose of the study was to analyze the content of radionuclides ( 137Cs and 90Sr) in soils near the settlements of the zone of radioactive contamination of the Volyn region and their spatial differentiation. Priority is given to agricultural lands, soils, crop products, which necessitates the organization of targeted monitoring of the agro industrial complex. Material and methods: Radioactivity from 137Cs and 90Sr in the soil originating in the Volyn region was studied from 1996 to 2018. Radiation control was carried out on the area of 59852 ha (arable land - 38897 ha, meadows and pastures - 20955 ha). Results: A significant part of the study area has elevated levels of radioactive contamination. The density of radionuclide contamination of agricultural soils in the settlements of the region has been determined. Density of pollution of all surveyed agricultural lands 137Cs ranges from 0.01 to 2.826 Ci/km2, and 90Sr from 0.01 to 0.048 Ci/km2. Conclusions: The radiological situation in the Volyn region (Ukraine) remains stable. There are slight fluctuations of 137Cs and 90Sr, which is due to changes in weather conditions, which leads to an increase or decrease in groundwater and as a consequence - the migration of radionuclides. The most polluted were the soils of administrative districts of Manevychi and Liubeshiv.

Modelling the mitigation speeds of 137Cs, 90Sr and 131I in the topsoils and assessment of the radiological hazards.

Fate modelling of artificial radionuclides (ARs) in top soils are necessary to assess the radiological effects to population. Among ARs, 137Cs, 90Sr and 131I are very important since the large abundances in the environment. In this study, the fates of 137Cs, 90Sr and 131I in the surface soil layers were simulated by the soil model which was developed by the Canadian Centre for Environmental Modelling and Chemistry (CEMC). The scenario that 137Cs, 90Sr and 131I contaminated in topsoil in the exclusion of Fukushima Daiichi nuclear power plant (NPP) accident was evaluated. The results show the expected time for the minimum hazardous level of exposure. It is 115.5 days after the exposure, when the total effective dose is 1 mSv y-1 in which 0.46 mSv y-1 from ingestion and 0.54 mSv y-1 from gamma exposure. Hazard levels due to exposure progresses are varied in order gamma exposure (82.14%) > ingestion (17.47%) > inhalation (0.39%). The hazard levels from radionuclides are varied in order 137Cs (63.34%) > 131I (33.48%) > 90Sr (3.18%).

Wear, tear and systematic repair: testing models of growth dynamics in conodonts with high-resolution imaging.

Conodont elements are the earliest mineralized vertebrate dental tools and the only ones capable of extensive repair. Two models of conodont growth, as well as the presence of a larval stage, have been hypothesized. We analysed normally and pathologically developed elements to test these hypotheses and identified three ontogenetic stages characterized by different anisometric growth and morphology. The distinction of these stages is independently corroborated by differences in tissue strontium (Sr) content. The onset of the last stage is marked by the appearance of wear resulting from mechanical food digestion. At least five episodes of damage and repair could be identified in the normally developed specimen. In the pathological element, function was compromised by the development of abnormal denticles. This development can be reconstructed as addition of new growth centres out of the main growth axis during an episode of renewed growth. Our findings support the model of periodic retraction of elements and addition of new growth centres. Changes in Sr content coincident with distinct morphology and lack of wear in the early life stage indicate that conodonts might have assumed their mature feeding habit of predators or scavengers after an initial larval stage characterized by a different feeding mode.

Assessment of multiple anthropogenic contaminants and their potential genotoxicity in the aquatic environment of Plitvice Lakes National Park, Croatia.

In this study, the influence of anthropogenic pollution on the aquatic environment of Plitvice Lakes National Park (PLNP) was investigated during 2011-2012 using a combination of chemical and cytogenetic analyses. Four groups of major contaminants [(volatile organic compounds: benzene, toluene, ethylbenzene, and xylenes (BTEX); persistent organochlorine pollutants: organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs); major and trace elements; anthropogenic radionuclides (90Sr, 134Cs, and 137Cs)] were determined in three aquatic compartments (water, sediment, fish). Mass fractions of inorganic constituents in different compartments reflected the geological background of the area, indicating their origin from predominantly natural sources. Levels of volatile and persistent organic compounds in water and fish, respectively, were very low, at levels typical for remote pristine areas. Analysis of anthropogenic radionuclides in water and sediment revealed elevated activity concentrations of 137Cs in water, and measurable 134Cs in the upper sediment layers from April 2011, possibly as a consequence of the Fukushima nuclear accident in March 2011. The potential genotoxicity of river and lake water and lake sediment was assessed under laboratory conditions using the alkaline comet assay on human peripheral blood lymphocytes, and measured levels of primary DNA damage were within acceptable boundaries. The results showed that despite the protected status of the park, anthropogenic impact exists in both its terrestrial and aquatic components. Although contaminant levels were low, further monitoring is recommended to make sure that they will not rise and cause potentially hazardous anthropogenic impacts.

A distinct section of the Early Bronze Age society? Stable isotope investigations of burials in settlement pits and multiple inhumations of the Únetice culture in central Germany.

OBJECTIVES: Inhumations in so-called settlement pits and multiple interments are subordinate burial practices of the Early Bronze Age Únetice culture in central Germany (2200-1700/1650 BC). The majority of the Únetice population was entombed as single inhumations in rectangular grave pits with a normative position of the body. The goal of the study was to test archaeological hypotheses that the deviant burials may represent socially distinct or nonlocal individuals. MATERIALS AND METHODS: The study comprised up to two teeth and one bone each of 74 human individuals from eight sites and faunal comparative samples. The inhumations included regular, deviant burials in so-called settlement or storage pits, and multiple burials. We investigated radiogenic strontium isotope compositions of tooth enamel ((87) Sr/(86) Sr) and light stable isotope ratios of carbon and nitrogen of bone collagen (δ(13) C, δ(15) N) aiming at the disclosure of residential changes and dietary patterns. RESULTS: Site-specific strontium isotope data ranges mirror different geological properties including calcareous bedrock, loess, and glacial till. Independent from burial types, they disclose low portions of nonlocal individuals of up to some 20% at the individual sites. The light stable isotope ratios of burials in settlement pits and rectangular graves overlap widely and indicate highly similar dietary habits. DISCUSSION: The analytical results let to conclude that inhumations in settlement pits and multiple burials were two of the manifold burial practices of the Early Bronze Age. The selection criteria of the individuals for the different forms of inhumation remained undisclosed.

Isotopic evidence of human mobility and diet in a prehistoric/protohistoric Fijian coastal environment (c. 750-150 BP).

OBJECTIVES: Bourewa, on the southwest coast of Viti Levu in Fiji, is a multi-period site that contained burials dated to the later Vuda Phase (750-150 BP), a period of climatic fluctuations that potentially impacted the availability of food resources. We aim to investigate diet and movement at this site during a time of possible ecological pressure and political change. MATERIALS AND METHODS: We analyzed δ(13) C, δ(15) N, and (87) Sr/(86) Sr of these Vuda Phase individuals (n = 25) interred at the site. By analyzing dentin and bone, both childhood diet and the diet within the past few years of adults' lives were examined. RESULTS: The paleodietary results suggested that adult diets consisted largely of low trophic level marine organisms. Dentin and bone isotopic values differed significantly: childhood diet involved consumption of more higher trophic level terrestrial foods. Most individuals displayed (87) Sr/(86) Sr ratios expected of people living along a marine coastline. However, a few individuals displayed (87) Sr/(86) Sr ratios and paleodietary values (δ(13) Cdentin , δ(15) Ndentin ) suggestive of living further inland or consuming a more terrestrial-based childhood diet. DISCUSSION: The results are compared with past studies of sites from Fiji and nearby archipelagoes, placing our interpretations into a wider regional context. The Bourewa community appears to have consumed more low trophic level marine foods than any nearby site, possibly because terrestrial foods were more difficult to acquire. Interpreting the childhood diet is challenging due to the paucity of ethnohistoric literature on Fijian childhood; small meals outside of communal mealtimes or feeding children terrestrial animal protein as a means of cultural buffering are potential explanations.

[Comparative evaluation of the prevalence of congenital malformations de novo in newborns from radiation-contaminated territories of the Bryansk region (1999-2014)].

On the basis of official statistics for 1999-2014 there was performed the comparative evaluation of the prevalence of congenital malformations de novo: polydactyly, reduction limb defects and multiple congenital malformations in newborns of radiation-contaminated areas of the Bryansk area residing in areas with the various density of radioactive contamination by long lived radionuclides cesium-137 (from 10.0 to 2523.4 kBq/m) and strontium-90 (from 0.7 to 42.5 kBq/m). The findings showed no statistically significant differences in the prevalence of polydactyly, reduction limb defects and multiple congenital malformations in newborns in the South-Western areas compared to medium regional values, although the maximum value of the amount of congenital malformations de novo is found in most radiation-contaminated areas.

Use of otolith for detecting strontium-90 in fish from the harbor of Fukushima Dai-ichi Nuclear Power Plant.

To clarify the level of contamination with radioactive cesium (radiocesium) discharged from Fukushima Dai-ichi Nuclear Power Plant (FDNPP), three fish species caught in the main harbor of FDNPP were subjected to γ-ray analysis. The concentration of radiocesium in muscle differed among individual fish, even those of similar size of the same species, and showed little relation to the standard length of fish. The maximum concentration of radiocesium (202 kBq/kg wet) was detected from fat greenling samples. A comparison to data from outside the port indicated that the level of radiocesium contamination inside the port was higher than that outside. We found that ß-rays were emitted from otoliths of fishes caught in the port of FDNPP. ß-ray intensities were correlated with the concentrations of radiocesium in muscles of the three fish species. In Japanese rockfish, the ß-ray count rates from otoliths were significantly correlated with the concentration of radiocesium and (90)Sr in the whole body without internal organs of Japanese rockfish. However, no ß-rays were detected from brown hakeling samples collected around FDNPP, suggesting that the detection of ß-rays from otoliths may indicate living in the main harbor of FDNPP.