Assessment of radiation hazards due to the concentration of natural radionuclides in the environment

A study of natural radionuclides and radon concentration of Hamirpur District of Himachal Pradesh, India is carried out using various methodologies. The activity concentration of the natural radionuclides viz. ²²⁶Ra, ²³²Th and ⁴⁰K is measured using high-resolution-based HPGe detector. Indoor radon measurements in the dwellings of Hamirpur district is carried out using LR-115 type II cellulose nitrate films in the bare mode. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K are 35.58, 54.95 and 580.58 Bq kg^?1, respectively. The annual average indoor radon value in the study area varies from 173.90 to 198.25 Bq m^?3, which is well within the recommended action level given by International Commission on Radiological Protection. The indoor radon values obtained in the present investigation are higher than the world average of 40 Bq m^?3. Radon concentration in water samples is measured using RAD7, an active radon detector. The annual effective dose for stomach and lung is determined from the measured value of radon concentration in water. To assess the radiation hazard of the natural radioactivity in all samples to the people, the radium equivalent activity, external hazard index, lifetime fatality risk, absorbed dose rate and total annual effective dose is estimated. The results signify that the studied area does not possess any radiation hazards due to the presence of natural radioactivity concentration.     

Occurrence of synthetic musk compounds in surface,underground, waste and processed water samples in Belgrade,Serbia

This study assessed the state of waters in Belgrade regarding pollution with musk compounds as the target contaminants. Eleven of these compounds were alicyclic, two were macrocyclic, and one was polycyclic. Solid-phase microextraction was used for the isolation of these compounds from waste, surface and underground waters and from processed water prepared for drinking, while comprehensive orthogonal two-dimensional gas chromatography with mass spectrometry was used as the final analytical method. In wastewater samples, galaxolide was detected in concentrations of 1.13 and 0.40 μg/L, while in the Sava River and underground water its concentrations were 0.09 and 0.038 μg/L. The lowest concentrations of the investigated musk compounds were detected in underground water samples, indicating that this is the cleanest water of all the analyzed sources with respect to musk compounds. Comparing the results of musk compound concentrations determined in surface river water samples and clean river water samples utilized for drinking, a lower concentration of these compounds was detected in the clean river water samples. The majority of musk compounds were found in waters utilized for drinking. Based on the concentration values, we conclude that the analyzed waters are moderately polluted with these compounds.     

Contents of radionuclides in soil and biota at the site of the Kraton-3 accidental underground nuclear test,Yakutia

The paper presents results of radiocological monitoring at the site of the Kraton-3 accidental underground nuclear test in Yakutia. The distribution and migration of ¹³⁷Cs, ⁹⁰Sr, ²³⁷Np, and ^238–240Pu in the soil and its living cover of the northern taiga are analyzed, and it is demonstrated that the radioecological conditions at the territory are still adverse in spite of the rehabilitation measures.     

Assessment of noise exposure and associated health risk in school environment

Noise exposure has become one of the most important factors in determining the quality of life in indoor environments. This paper assesses and analyzes noise exposure levels at school and preschool classrooms with different indoor environments. The sound level [A-weighting equivalent steady sound level L _Aeq (dBA)] was measured using a CEL-63× digital sound level meter. The noise level measurements were performed inside two preschools at three classrooms (an activity room, classroom KG1 and classroom KG2) and three schools at different classrooms, starting from grade 1 to grade 12. The logarithmic average noise levels (L _{Aeq avg}) and the 8-h average noise exposure level (L _{EX, 8-h}) were estimated for each classroom. Furthermore, health risk issues associated with the exposure to high noise levels were investigated using a questionnaire and an interview with more than 250 teachers at the preschools and the schools. Then, the results were analyzed using different statistical tools and were compared with the World Health Organization, Occupational Health and Safety and National Institute for Occupational Safety and Health standards. Also, the results were compared with those from different countries worldwide. The study results show that the 8-h average noise exposure level exceeded the allowable limits in some schools, which indicates that students and teachers can face a serious health effects from noise exposure. The comparisons show that the values of noise levels in Kuwait are higher than those in different countries. The maximum value of noise levels was found in secondary schools. The health problems found during the survey are potentially associated with issues related to hearing, voice, headache and the physiological function of teachers.     

Evaluation of radiation dose due to naturally occurring radionuclides in rock samples of different origins collected from Azad Kashmir

The state of Azad Kashmir is rich in three types of rocks, namely, sedimentary, metamorphic, and igneous rocks. These rocks contain extensive deposits of graphite, marble, limestone, quartzite, granite, dolerite, and sandstone, which are widely used for the construction of dwellings in Azad Kashmir and Pakistan. Therefore, knowledge about the presence of natural radioactivity in these materials is desirable to assess the radiological hazards associated with it. In this context, 30 rock samples were collected from different geologic formations of the Muzaffarabad Division, Azad Kashmir. After processing the samples, the specific activities of ²²⁶Ra, ²³²Th, and ⁴⁰ K in them were measured using a P-type coaxial high-purity germanium detector. The observed highest dose rate values for sedimentary, metamorphic, and igneous rocks have been found to be 83.16 ± 1.08, 135.87 ± 1.18, and 115.98 ± 1 nGy ⋅ h^–1, respectively. The radium equivalent activity (Ra_eq) varied from 23.76 ± 1.15 for dolerite sample (igneous rock) to 293.69 ± 2.60 Bq ⋅ kg^–1 for marble (metamorphic rock). The Ra_eq values of all rock samples are lower than the limit mentioned in the Organization for Economic Cooperation and Development (OECD, 1979) report (370 Bq ⋅ kg^–1, equivalent to γ-dose of 1.5 mSv ⋅ y^–1). The values of external (H_ex) and internal hazard indices (H_in) are less than unity. The mean outdoor and indoor annual effective dose equivalents are 0.073 mSv ⋅ y^–1 and 0.29 mSv ⋅ y^–1, respectively. The mean (over all types of rock samples) annual effective dose equivalent is reported as 0.36 mSv ⋅ y^–1.     

Stratigraphic and lithologic characteristics of Pleistocene fluvial deposits in the Danube and Sava riparian area near Belgrade (Serbia)

The Quaternary sediments in the Danube and Sava riparian area near Belgrade have a considerable thickness. Several categories of deposits (fluvial-lacustrine, fluvial and aeolian) of Pliocene and Quaternary age have been identified. Their thickness, granulometric composition and paleontological features change depending on the distance from the recent Danube and Sava riverbeds. The Pleistocene fluvial deposits are underlain by sediments of the Late Miocene (Sarmatian and Pannonian) or the Plio-Pleistocene age, and are overlain by fluvial-palustrine deposits of the Pleistocene age and recent alluvial deposits. Pleistocene fluvial deposits that form a major part of the Quaternary sediments, have a great significance, since they are proved to be excellent collectors of ground water. Although these deposits are at lower altitudes in the area of Srem, they could be correlated with the high Danube and Morava terraces in Serbia and Drava in Croatia on the basis of their lithologic and paleontological features.     

Evidence in pre-2.2 Ga paleosols for the early evolution of atmospheric oxygen and terrestrial biota

The loss of Fe from some pre-2.2 Ga paleosols has been considered by previous investigators as the best evidence for a reduced atmosphere prior to 2.2 Ga. I have examined the behavior of Fe in both pre- and post-2.2 Ga paleosols from depth profiles of Fe3+/Ti, Fe2+/Ti, and sigma Fe/Ti ratios, and Fe3+/Ti vs. Fe2+/Ti plots. This new approach reveals a previously unrecognized history of paleosols. Essentially all paleosols, regardless of age, retain some characteristics of soils formed under an oxic atmosphere, such as increased Fe3+/Ti ratios from their parental rocks. The minimum oxygen pressure (PO2) for the 3.0-2.2 Ga atmosphere is calculated to be about 1.5% of the present atmospheric level, which is the same as that for the post-1.9 Ga atmosphere. The loss of sigma Fe, common in paleosol sections of all ages, was not due to a reducing atmosphere, but to reductive dissolution of ferric hydroxides formed under an oxic atmosphere. This reductive dissolution of ferric hydroxides occurred either (1) after soil formation by hydrothermal fluids or (2) during and/or after soil formation by organic acids generated from the decay of terrestrial organic matter. Terrestrial biomass on the early continents may have been more extensive than previously recognized.     

Assessment of the pseudo total metal content in alluvial sediments from Danube River,Serbia

We used elemental carbon, nitrogen, hydrogen and sulfur as well as ratios of hydrogen and nitrogen with total organic carbon for investigation of source and conditions of organic matter in alluvial Danube sediments. We also determined the pseudo total concentrations of metals presented as a sum of extracted concentration after five sequential extraction steps. The pseudo total metal concentrations were found to be (mg kg⁻¹) for Mn, 666; Fe, 25,852; Mg, 16,193; K, 2,063; Ni, 32.4; Zn, 72.2; Pb, 15.0; Cu, 26.0 and for Cr, 15.9. Correlation analysis and two multivariate analysis methods (principal component and cluster analysis) were helpful in determining the associations between the pseudo total extracted fractions of metals and with elemental carbon, hydrogen, nitrogen, sulfur, total inorganic and organic carbon. These correlations will help us to identify substrates of trace metals in different oxic/anoxic conditions. The correlation results of the trace metals and Fe, K, Mg and Mn suggest their adsorption, mainly onto Fe and Mn (hydro)oxides and K alumosilicates, whereas correlations of metals with sulfur indicate that they were precipitated as Fe-sulfides.     

Sequence and scale of changes in the terrestrial biota during the Cretaceous (based on materials from fossil resins)

Сomparative analysis of arthropod assemblages found in Cretaceous fossil resins is provided. Arthropod-bearing Cretaceous resin sites are reviewed, and a list of arthropod records (identified to the family level) published up to 2015 is provided. Also, new records of mites, and new arthropod records from the Siberian resins are given. An efficient method for extracting amber from loose sediments in situations of limited infrastructure but easy access to water is described as well.The sequence of arthropod assemblages in Cretaceous resins according to their evolutionary aspect does not match their geological sequence. This can be only partly explained by taphonomic constraints and inadequacy of the material: there is a deeper difference between somewhat contemporary assemblages than was characteristic of Permian assemblages studied in a similar way in previous studies. Our results confirm the earlier hypothesis that the Palaeozoic–Mesozoic biotic crisis was not so much a mass extinction as a biotic reorganisation that opened the way to diversification. These results might indicate a peculiar feature of the immediate effects of such reorganisations, namely that Mesozoic–Cenozoic communities became differentiated in their compositions much deeper than Palaeozoic ones (i.e., that their constituent groups acquired the ability to evolve much deeper changes while adapting to the ecological specifics of their environments). A transformation of organisms and/or their communities took place, comparable in scope to the rise of skeletal fauna in the Cambrian. The difference between these two transformations is that the later one resulted not from a particular adaptation (the skeleton) but from the ability to specialize more deeply than was possible in the Palaeozoic.     

Evidence in pre-2.2 Ga paleosols for the early evolution of atmospheric oxygen and terrestrial biota: comment and reply

The major points of disagreement between Holland and Rye and Ohmoto concern (1) the behavior of ferric iron. (2) the mechanisms of Fe loss. (3) the identification of real paleosols, and (4) the ages of some paleosols.     

Determination of the radiation dose due to radon ingestion and inhalation

The distribution of radon in ground and surface water samples in Sankey Tank and Mallathahalli Lake areas was determined using Durridge RAD-7 analyzer with RAD H₂O accessory. The radiation dose received by an individual falling under different age groups (viz., 3 months; 1, 5, 10, 15 years and adult) depending upon their average annual water consumption rate was attempted. The mean radon activity in surface water of Sankey Tank and Mallathahalli Lake was 7.24 ± 1.48 and 11.43 ± 1.11 Bq/L, respectively. The average radon activities ranged from 11.6 ± 1.7 to 381.2 ± 2.0 Bq/L and 1.50 ± 0.83 to 18.9 ± 1.59 Bq/L, respectively, in 12 groundwater samples each around Sankey Tank and Mallathahalli Lake areas. Majority of the measured groundwater samples (viz., 100 % in Sankey Tank area and 75 % in Mallathahalli Lake area) showed mean radon values above the EPA’s maximum contaminant level of 11.1 Bq/L and only 66.67 % of samples in Sankey Tank area showed radon above the WHO and EU’s reference level of 100 Bq/L. The overall radiation dose due to radon emanating from water in the study area was increasing with increase in age and water consumption rates, but significantly lower than UNSCEAR and WHO recommended limit of 1 mSv/year except for few groundwater samples in Sankey Tank area (i.e., 0.92, 0.99 and 1.39 mSv/year). The radiation dose rate received by bronchial epithelium via inhalation was very high compared to that by stomach walls via ingestion.     

Assessment of groundwater pollution due to tannery industries in and around Dindigul, Tamilnadu, India

The overexploitation of groundwater in some parts of the country induces water quality degradation. The untreated industrial effluents discharged on the surface causes severe groundwater pollution in the industrial belt of the country. This poses a problem of supply of hazard free drinking water in the rural parts of the country. There are about 80 tanneries operating in and around Dindigul town in upper Kodaganar river basin, Tamilnadu, India. The untreated effluents from the tanneries have considerably affected the quality of groundwater in this area. To assess the extent of groundwater deterioration, a detailed analysis of groundwater quality data has been carried out. The concentration of cations such as Calcium (Ca²⁺), Magnesium (Mg²⁺), Sodium (Na⁺) and Potassium (K⁺), and anions such as Bicarbonate (HCO₃^–), Sulphate (SO₄^2–), Chloride (Cl^–) and Nitrate (NO₃^–) in the groundwater have been studied. Apart from these constituents, pH, electrical conductivity (EC), total dissolved solid and total hardness (TH as CaCO₃) were also studied. The correlation of these constituents with the EC has been carried out. The highest correlation is observed between EC and chloride with a correlation coefficient of 0.99. Progressive reduction in correlation coefficients for Mg²⁺, (Na⁺ + K⁺), Ca²⁺ and SO₄^2– are observed as 0.91, 0.87, 0.86 and 0.56, respectively. It is found that the quality of groundwater in the area under investigation is deteriorated mainly due to extensive use of salt in the leather industries.     

Distribution of natural uranium,thorium, lead,and polonium radionuclides in tidal phases of a Delaware salt marsh

Natural radionuclides in the uranium and thorium series were measured in solid tidal phases (suspended particles, bottom sediment, surface microlayer colloids) of a salt marsh in lower Delaware. The purpose was to identify potential processes responsible for trace element cycling (sources, redistribution and exchange) in salt water marshes and with their coastal waters. Generally, concentrations of U, Th,²¹⁰Pb, and²¹⁰Po on the tidal solid phases suggest a general mechanism by which tidal marshes appear to be trapping the nuclides into their interiors. The processes may include transport of enriched fine particles into the marsh, capture by salt marsh grass and chemical fixation by redox processes at the sediment surface. Specifically, the uranium contents of most of the samples are similar with activity ratios²³⁴U²³⁸U≧1, indicating a mixture of detrital and nondetrital (authigenic) uranium inputs such as seawater or ground water. Since the²³⁰Th daughter is generally deficient by about 50%, the authigenic enrichment process appears to favor uranium and is potentially linked to the extensive diagenetic sulfur redox cycle of salt marsh sediments. The²¹⁰Po/²¹⁰Pb activity ratio is less than one on Spartina adsorbed solids, and could suggest a general process in salt marshes which favors²¹⁰Pb enrichment by atmospheric fallout over enrichment of²¹⁰Po on time scales of weeks which correspond to complete tide marsh exchange. A²²⁸Th/²³²Th activity ratio of less than unity on the solids adsorbed onto marsh grass suggests a net process whereby diffusive loss of the intermediate daughter²²⁸Ra from the adsorbed solids to tidal waters dominates over potential²²⁸Th scavenging by suspended sediment.     

Assessment of the plume dispersion due to chemical attack on April 4, 2017, in Syria

Natural Hazards - Sediment-related disasters may cause high casualties and economic losses in mountainous zones. The occurrence of these natural hazards in developing countries, where recovery...     

Evaluation of change in subsurface thermal environment due to groundwater flow in the Tokyo Lowland,Japan

Information on the distribution of subsurface temperature and hydraulic heads at 24 observation wells in and around the Tokyo Lowland, the eastern part of the Tokyo Metropolitan area, were examined to make clear the relationship between groundwater and the subsurface thermal environment in the urban area. Minimums in temperature–depth logs due to subsurface temperature increasing at shallow parts were recognized in 21 wells. This fact shows subsurface temperature is affected by ground surface warming in almost all of this area. Deeper than minimums, where the effects of surface warming became relatively small, regional variation is observed as follows: high temperatures are shown in the central part to the southern part, and low temperatures shown in the inland to eastern part. The high temperature area corresponds to an area where the lower boundary of groundwater flow is relatively shallow. This area corresponds also to an area with severe land subsidence resulting from excessive groundwater pumping. It is considered that this high temperature area is formed by the effects of upward groundwater flow affected by hydrogeological conditions and pumping. On the other hand, a comparison between past data (1956–1967) and present data (2001–2003) revealed widespread decreasing temperature in the inland area. This is explained by downward groundwater flow based on an analysis of temperature–depth logs. This fact suggests that subsurface temperature is not only increasing from the effects of surface warming but also decreasing from the effects of groundwater environment change due to pumping.     

The relative mobility of natural (Th,Pb and Po) and fallout (Pu,Am, Cs) radionuclides in the coastal marine environment: results from model ecosystems (MERL) and Narragansett Bay

The relative mobility of nuclides of Pb, Th, Pu, and Cs, which are widely used as geochemical tracers for sedimentation and bioturbation. was investigated in artificial microcosm tanks (MERL) and in Narragansett Bay. Their mobility was characterized by their removal rates from the water column, their affinity toward particles and their degree of penetration into the surface sediments. Pb, Th, and Pu transport was controlled predominantly by the affinity of these elements to particles, and the transport parameters of the particles themselves (i.e. sediment resuspension and mixing rates). Because of its low distribution coefficient, transport of Cs was controlled by molecular diffusion through pore water in the winter, while in summer, Cs transport was enhanced due to bioturbation. The increase with depth of the $\text{Cs}\text{Pu}$ ratio in core profiles of MERL and Narragansett Bay sediments is thus caused primarily by the higher mobility of Cs.