226Ra concentration in the teeth of habitants of areas with high level of natural radioactivity in Ramsar

The level of natural radiation in some regions of Ramsar, a northern coastal city of Iran, is known to be among the highest levels of natural radiation in the world. 226Ra existing in high concentrations in the soil of this region is washed by underground water and transferred to the surface. In this way, 226Ra enters the food chain of residents and substitutes within the hard body tissues of humans. 226Ra is one of the so-called bone seekers as its metabolic processes in the human body are similar to calcium and remains in hard tissues of body because of its long half-life, and being an alpha emitter causes dangerous effects on human health. The purpose of this study is to determine the concentration of 226Ra in the teeth of residents of these high-level natural radiation areas, compared with a control group. Thirteen teeth in five groups were studied as the case group and thirteen teeth in five corresponding control groups were inspected. The mean values of the activity of 226Ra in the case group and in the control group were 0.32 and 0.18mBqg(-1), respectively.     

An assessment of the external radiological impact in areas of Greece with elevated natural radioactivity

In the present study, the radiological impact assessment in three selected areas of elevated natural radioactivity in Greece is attempted, based on measurements, theoretical relations, and simple model application. These areas are Milos--an island of volcanic origin in Cyclades Archipelago, Ikaria--an island in the Eastern Aegean Sea and Loutraki--a coastal area in mainland Greece. These areas are characterized by their geothermal springs and vents, which emit fluids into the littoral and sublittoral zones. The results include: (a) the exposure dose rates assessed by a car-borne scintillation spectrometry system; (b) laboratory measurements of the activity concentrations of the gamma-emitters of 238U and 232Th series and 40K in soil, spring water, seawater and sediments by gamma-spectrometry; (c) estimations of the effective dose rate equivalents and health risk assessment for humans and external dose rates for natural aquatic populations in relation to organism habitat; and (d) a radiological evaluation for the environmental quality, in terms of the discrete zones of impact of ionizing radiation.     

Effects of non-human species irradiation after the Chernobyl NPP accident

The area affected by the Chernobyl Nuclear Power Plant accident in 1986 has become a unique test site where long-term ecological and biological consequences of a drastic change in a range of environmental factors as well as trends and intensity of selection are studied in natural settings. The consequences of the Chernobyl accident for biota varied from an enhanced rate of mutagenesis to damage at the ecosystem level. The review comprehensively brings together key data of the long-term studies of biological effects in plants and animals inhabiting over 20 years the Chernobyl NPP zone. The severity of radiation effects was strongly dependent on the dose received in the early period after the accident. The most exposed phytocenoses and soil animals' communities exhibited dose dependent alterations in the species composition and reduction in biological diversity. On the other hand, no decrease in numbers or taxonomic diversity of small mammals even in the most radioactive habitat was shown. In a majority of the studies, in both plant and animal populations from the Chernobyl zone, in the first years after the accident high increases in mutation rates were documented. In most cases the dose-effect relationships were nonlinear and the mutation rates per unit dose were higher at low doses and dose rates. In subsequent years a decline in the radiation background rate occurred faster than reduction in the mutation rate. Plant and animal populations have shown signs of adaptation to chronic exposure. In adaptation to the enhanced level of exposure an essential role of epigenetic mechanisms of gene expression regulation was shown. Based on the Chernobyl NPP accident studies, in the present review attempts were made to assess minimum doses at which ecological and biological effects were observed.     

High levels of natural radioactivity in biota from deep-sea hydrothermal vents: a preliminary communication

Hydrothermal deep-sea vent fauna is naturally exposed to a peculiar environment enriched in potentially toxic species such as sulphides, heavy metals and natural radionuclides. It is now well established that some of the organisms present in such an environment accumulate metals during their lifespan. Though only few radionuclide measurements are available, it seems likely that hydrothermal vent communities are exposed to high natural radiation doses. Various archived biological samples collected on the East Pacific Rise and the Mid-Atlantic Ridge in 1996, 2001 and 2002 were analysed by ICP-MS in order to determine their uranium contents (²³⁸U, ²³⁵U and ²³⁴U). In addition ²¹⁰Po–Pb were determined in 2 samples collected in 2002. Vent organisms are characterized by high U, and Po–Pb levels compared to what is generally encountered in organisms from outside hydrothermal vent ecosystems. Though the number of data is low, the results reveal various trends in relation to the site, the location within the mixing zone and/or the organisms' trophic regime.     

Heat waves and floods in urban areas: a policy-oriented review of ecosystem services

Urbanisation is increasing and today more than a half of the world’s population lives in urban areas. Cities, especially those where urbanisation is un-planned or poorly planned, are increasingly vulnerable to hydro-meteorological hazards such as heat waves and floods. Urban areas tend to degrade the environment, fragmenting and isolating ecosystems, compromising their capacity to provide services. The regulating role of ecosystems in buffering hydro-meteorological hazards and reducing urban vulnerability has not received adequate policy attention until now. Whereas there is a wide body of studies in the specialised biological and ecological literature about particular urban ecosystem features and the impacts of hazards upon people and infrastructures, there is no policy-driven overview looking holistically at the ways in which ecosystem features can be managed by cities to reduce their vulnerability to hazards. Using heat waves and floods as examples, this review article identifies the aggravating factors related to urbanisation, the various regulating ecosystem services that buffer cities from hydro-meteorological impacts as well as the impacts of the hazards on the ecosystem. The review also assesses how different cities have attempted to manage related ecosystem services and draws policy-relevant conclusions.     

Assessment of natural or enhanced in situ bioremediation at a chlorinated solvent-contaminated aquifer in Italy: a microcosm study

A microcosm study was used to assess the potential for in situ natural or enhanced bioremediation at a chloroethane- (i.e., tetrachloroethane, TeCA) and chloroethene-contaminated (i.e., tetrachloroethene, PCE; trichloroethene, TCE) groundwater in Northern Italy. All the live microcosms were positive for dechlorination, indicating the presence of an active native dechlorinating population in the subsurface. All the tested electron donors (i.e., yeast extract, lactate, butyrate, hydrogen) promoted enhanced dechlorination of chlorinated contaminants. Lactate- and butyrate-amended microcosms performed the best, and also dechlorinated the solvents past cis-dichloroethene (cis-DCE). The microcosm bioaugmented with a PCE-dechlorinating mixed culture containing Dehalococcoides spp. dechlorinated groundwater contaminants to DCE, vinyl chloride (VC), and ethene (ETH). In conclusion, results from this microcosm study indicate the potential for enhancing full dechlorination at the contaminated site, through a proper addition of a suitable electron donor (e.g., lactate or butyrate) and/or through bioaugmentation with a Dehalococcoides-containing culture.     

The influence of urbanization on natural radiation levels in anomalous areas

This paper verifies the effects of urbanization on the original levels of environmental gamma radiation in an anomalous area. The fieldwork was done in the city of Guarapari, on the seacoast of the state of Espírito Santo, Brazil. This place was chosen because the whole region is naturally rich in monazite sand, which contains thorium and uranium. A similar study was also carried out in the 1960s. The measurements were done using an inorganic NaI scintillometer detector with Cu+Pb filters coupled to a scaler. The methodology of measurements used was similar to the one applied in the fieldwork carried out in the 1960s. In addition, a simulation was performed in the laboratory, to determine the attenuation of the materials used in the urbanization of the region. The results of this work clearly show that there was a reduction in the levels of external radiation in the streets and squares of Guarapari. It was concluded that the reduction was due to attenuation by the materials used in the urbanization.     

Assessment of the natural radioactivity and radiological hazards in Turkish cement and its raw materials

The natural radioactivity due to presence of (226)Ra, (232)Th and (40)K radionuclides in raw materials, intermediate products (clinker) and end products (22 different cement types) was measured using a gamma-ray spectrometry with HPGe detector. The specific radioactivity of (226)Ra, (232)Th and (40)K in the analyzed cement samples ranged from 12.5+/-0.3 to 162.5+/-1.7Bqkg(-1) with a mean of 40.5+/-26.7Bqkg(-1), 6.7+/-0.3 to 124.9+/-2.5Bqkg(-1) with a mean of 26.1+/-18.9Bqkg(-1) and 64.4+/-2.3 to 679.3+/-18.2Bqkg(-1) with a mean of 267.1+/-102.4Bqkg(-1), respectively. The radium equivalent activity (Ra(eq)), the gamma-index, the emanation coefficient, the (222)Rn mass exhalation rate and the indoor absorbed dose rate were estimated for the radiation hazard of the natural radioactivity in all samples. The calculated Ra(eq) values of cement samples (37.2+/-8.7-331.1+/-15.5Bqkg(-1) with a mean of 98.3+/-53.8) are lower than the limit of 370Bqkg(-1) set for building materials. The Ra(eq) values were compared with the corresponding values for cement of different countries. The mean indoor absorbed dose rate is slightly higher than the population-weighted average of 84nGyh(-1).     

Spatial distribution of natural radioactivity levels in topsoil around the high-uranium mineralization zone of Kylleng-Pyndensohiong (Mawthabah) areas, West Khasi Hills District, Meghalaya, India

A study of background radiation and the distribution of radionuclides in the environment of the proposed uranium mining sites of Kylleng-Pyndensohiong (Mawthabah) areas, West Khasi Hills District, Meghalaya, India, has been carried out with the objective of establishing a baseline radiation level of the region. Topsoil samples collected from the region are analysed for radioactivity measurements of primordial radionuclides by gamma-spectrometry technique. Direct dose measurement using a survey meter was also carried out simultaneously. Measurement carried out in the region shows that the activity concentration of (238)U and (232)Th in soil samples is found to be highest in Kylleng with respective median values of 335.3Bqkg(-1) and 283.9Bqkg(-1) followed by Syngkai with activity concentration of 285.3Bqkg(-1) and 257.4Bqkg(-1) for (238)U and (232)Th, respectively. The distribution of (40)K concentration in the study area is found to be in the range of 173.1-359.0Bqkg(-1) which is below the global and Indian average values of 420Bqkg(-1) and 394Bqkg(-1), respectively. The contribution of the primordial radionuclides to the total dose of the study area is found to be very high with a range of 136.8-334.5nGyh(-1) in comparison to the global as well as Indian average values.     

Effects of climate change on species distribution, community structure, and conservation of birds in protected areas in Colombia

Climate change is expected to cause shifts in species distributions worldwide, threatening their viability due to range reductions and altering their representation in protected areas. Biodiversity hotspots might be particularly vulnerable to climate change because they hold large numbers of species with small ranges which could contract even further as species track their optimal habitat. In this study, we assessed the extent to which climate change could cause distribution shifts in threatened and range-restricted birds in Colombia, a megadiverse region that includes the Tropical Andes and Tumbes-Choco-Magdalena hotspots. To evaluate how climate change might influence species in this region, we developed species distribution models using MAXENT. Species are projected to lose on average between 33 and 43 % of their total range under future climate, and up to 18 species may lose their climatically suitable range completely. Species whose suitable climate is projected to disappear occur in mountainous regions, particularly isolated ranges such as the Sierra Nevada de Santa Marta. Depending on the representation target considered, between 46 and 96 % of the species evaluated may be adequately represented in protected areas. In the future, the fraction of species potentially adequately represented is projected to decline to 30–95 %. Additional protected areas may help to retain representativeness of protected areas, but monitoring of species projected to have the largest potential declines in range size will be necessary to assess the need of implementing active management strategies to counteract the effects of climate change.     

Effects of environmental factors on low-molecular-weight peptides of fishes: a review

The present state of knowledge of the influence of heavy metals and some other environmental factors on fish metallothioneins, low-molecular-weight tissue polypeptides, is considered. The ecological-biochemical role of these polypeptides and their involvement in the development of adaptive responses of organs to heavy metal accumulation are demonstrated.Translated from Ekologiya, No. 1, 2005, pp. 48–54.Original Russian Text Copyright © 2005 by Smirnov, Sukhovskaya, Nemova.     

Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review

Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of ⁴⁰K and of ²³⁸U, ²³²Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y⁻¹), the major part of which (99 %) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg⁻¹ for ²³⁸U, from 44 to 255 Bq kg⁻¹ for ²²⁶Ra, from 59 to 205 Bq kg⁻¹ for ²¹⁰Pb, from 9 to 41 Bq kg⁻¹ for ²²⁸Ra (²³²Th) and from 59 to 227 Bq kg⁻¹ for ⁴⁰K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg⁻¹ for ²³⁸U, from 142 to 605 Bq kg⁻¹ for ²²⁶Ra, from 133 to 428 Bq kg⁻¹ for ²¹⁰Pb, from 27 to 68 Bq kg⁻¹ for ²²⁸Ra (²³²Th) and from 204 to 382 Bq kg⁻¹ for ⁴⁰K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5 man-Sv (GW a)⁻¹ for typical old and modern coal-fired power plants, respectively.     

生态脆弱区自然资本可持续利用及驱动机制--以宁夏为例

自然资本的分类测度和分区管理是可持续发展领域的核心议题。文章基于改进后的三维生态足迹模型,分析了2008—2017年宁夏及其各地级市自然资本利用的时空演变特征,并运用偏最小二乘法揭示了自然资本利用演变的驱动机制,旨在为生态脆弱区自然资本的可持续利用、社会经济的协调发展和生态文明建设提供参考。结果显示:①10年来宁夏人均生态足迹以年均5.01%的速率从3.146 hm²增至4.564 hm²,人均生态承载力相对稳定,人均生态赤字由2.462 hm²扩大至3.839 hm²,自然资本的供需矛盾愈加尖锐;市域尺度上,除固原市外其他各市生态赤字明显,总体上呈由南向北递增趋势。②足迹深度和足迹广度表明流量资本已无法满足需求,对存量资本的消耗成为社会经济发展的常态;市域尺度上,足迹深度呈“北高南低”的分布特征,而足迹广度的空间分布与其相反,二者存在显著的地域互补性。③从地类组分构成来看,林地、草地和水域是全区存量资本消耗的主要方式,耕地尚处于流量资本占用状态,建筑用地已过渡为存量资本;市域尺度上,自然资本利用的可持续性呈“南强北弱”格局,各地类间自然资本利用差异显著。④偏最小二乘回归模型揭示能源消耗、社会消费、经济发展和资源禀赋条件是影响宁夏自然资本利用的显著因素,而人口规模、对外贸易、生态建设、科技进步和产业结构演化对自然资本利用的影响程度较轻;市域尺度上自然资本利用的驱动力差异显著。最后,基于自然资本利用空间分异特征,从供需视角提出了自然资本可持续利用的对策建议和优化路径。     

Impact of invasive mammal species on natural ecosystems: An example of the Prioksko-Terrasnyi Biosphere Reserve

On the basis of Annals of Nature of the Prioksko-Terrasnyi Biosphere Reserve, its colonization by invasive mammal species and the current state of their populations have been analyzed. In the mammal fauna of the reserve, 13 out of 60 species can be classified as invasive. They differ in the degree of impact on the biota. The house mouse, Norway and black rats, and European bison have virtually no effect on natural ecosystems; the effect of the muskrat, raccoon dog, American mink, red and axis deer is insignificant; and that of stray dogs and Tartarian roe deer is considerable. The European beaver and wild boar play an environment-forming role. The impact of beaver activities is strong but local, whereas activities of wild boars put into question the very possibility of conservation and analysis of representative biosphere areas and biological diversity in the reserve.     

Distribution of some natural gamma-emitting radionuclides in the soils of the coastal areas of Nigeria

Studies on the radiation level and the radionuclide distribution of some naturally occurring radioactive materials (NORM) in the soils of the coastal areas of Southern Nigeria were undertaken. The purpose of this study is to provide baseline data for the effective monitoring of unforeseeable radioactive fallout in these areas where a lot of oil exploration activities are going on. The radioactivity concentrations of these naturally occurring radionuclides (specifically (40)K, (238)U and (232)Th) in the soil samples were analyzed using a high-resolution, low-background, hyper-pure coaxial gamma-ray detector (EG&G ORTEC HPGe) coupled to an amplifier and multi-channel analyzer. The activity of (40)K ranges between 111.9 and 444.7 kBq kg(-1) with a median value of 283.28 kBq kg(-1); the activity of (226)Ra (a daughter of (238)U) varies from 23.24 to 43.66 kBq kg(-1) with a median value of 34.54 kBq kg(-1); and that of (232)Th ranges from 6.45 to 12.79 kBq kg(-1) with a median value of 9.17 kBq kg(-1). The mean absorbed dose rate in air due to these NORM is found to be (33.655+/-3.409) nGy h(-1). The correlation analyses showed a positive relationship between the three radionuclides in all the five coastal states.     

Long-term stability of decontamination effect in recreational areas near the town Novozybkov, Bryansk Region, Russia

In 1995 and 1997, experimental decontamination campaigns were carried out in two recreational areas, Novie Bobovichi and Guta-Muravinka, near the town of Novozybkov, Bryansk Region, Russia. These areas were strongly affected by the Chernobyl fallout in 1986. In order to examine the long-term stability of the clean-up procedures, a programme has been carried out to continuously monitor the radiological situation in and around the decontaminated areas. This follow-up program consists of regular (1-3 times per year) measurements of absorbed gamma-dose rate in air (DR) at reference indoor and outdoor locations, repeated DR measurements on a grid, and gamma-spectrometric analysis of soil and other environmental samples. Very similar dynamics of the Chernobyl-related DR, mostly attributed to radiocaesium decay, were found in all the locations. For the period under study (September 1995-May 2003), the half-lives (years) for the reduction in radiocaesium-dependent DR contribution due to contaminant migration (in the following termed 'DRM half-lives') were, respectively, 52+/-26, 57+/-23, 43+/-21, 46+/-15, and 80+/-56 for the following locations: untreated outdoors, treated outdoors, untreated indoors, treated indoors, and undisturbed forest-grassland plots outside the recreational areas. These relatively high values of the current DRM half-lives correspond very well with the results of soil core analyses, which showed no time-dependent changes in the mean mass depths of the (137)Cs distribution, neither at treated nor at undisturbed plots. The following signs of natural restoration of the disturbed forest-meadow ecosystems have been observed at treated areas: formation of a new litter layer, development of grassy spots, mushroom growths and new generations of pines and birches. The levels of the (137)Cs content in grass and mushrooms from treated plots were one or two orders of magnitude lower, than those registered in the samples from untreated areas. The follow-up study demonstrates the long-term stability and efficiency of the decontamination carried out. There are two main reasons for the sustainment of the effects: careful implementation of adequate clean-up procedures and natural strong fixation of radiocaesium in soil-associated matrices of the ecosystems.     

High natural radiation exposure in radon spa areas: a detailed field investigation in Niska Banja (Balkan region)

The measurement campaigns have been done in the rural community of Niska Banja, a spa town located in southern Serbia, to evaluate population exposure to natural radioactivity. After a screening survey in 200 houses, annual radon and thoron concentrations were measured in 34 houses, and in 2004 a detailed investigation was carried out at six houses with elevated indoor radon concentrations. The paper presents the results of these detailed measurements. The complementary techniques were applied to determine radon and thoron concentrations in indoor air, in soil gas, radon exhalation from soil, soil permeability, and indoor and outdoor gamma doses. Soil and water samples were collected and analysed in the laboratory. Indoor radon and thoron concentrations were found to be more than 1kBqm(-3) and 200Bqm(-3), respectively. Extremely high concentrations of soil-gas radon (>2000kBqm(-3)) and radon exhalation rates (1.5mBqm(-2)s(-1)) were observed. These results will be utilised to set up the methodology for a more systematic investigation.     

Genotoxicity and cytotoxicity assay of water sampled from the underground nuclear explosion site in the north of the Perm region (Russia)

The results of our study revealed a local biologically relevant surface water contamination in the radionuclide anomaly in the north of Russia (Perm region) by means of Allium schoenoprasum L. anaphase-telophase chromosome aberration assay. This radionuclide anomaly was formed in 1971 as a result of an underground nuclear explosion with soil excavation. Specific activities of main dose-forming radionuclides in all examined reservoirs are below intervention levels officially adopted in Russia for drinking water. We found that (90)Sr significantly contributes to induction of cytogenetic disturbances. Our previous data and the data described here suggest that metal and radionuclide combined exposure (with the dose below permissible exposure limits for human) may cause substantial biological effects. These effects are in part due to synergic response. The findings described here indicated that development of a new concept of radiation protection for humans and biota should be based on the clear understanding of biological effects of low doses of radiation in chronic exposure to multi-pollutant mixtures.     

Comparative study of natural radioactivity levels in soil samples from the Upper Siwaliks and Punjab,India using gamma-ray spectrometry

Natural radioactive materials under certain conditions can reach hazardous radiological levels. So, it becomes necessary to study the natural radioactivity levels in soil to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. The natural radionuclide (²²⁶Ra, ²³²Th, and ⁴⁰K) contents in soil were determined for 26 locations around the Upper Siwaliks of Kala Amb, Nahan and Morni Hills, Northern India, using high-resolution gamma-ray spectrometric analysis. It was observed that the concentration of natural radionuclides viz., ²²⁶Ra, ²³²Th and ⁴⁰K, in the soil varies from 28.3 ± 0.5 to 81.0 ± 1.7 Bq kg⁻¹, 61.2 ± 1.3 to 140.3 ± 2.6 Bq kg⁻¹ and 363.4 ± 4.9 to 1002.2 ± 11.2 Bq kg⁻¹ respectively. The total absorbed dose rate calculated from activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K ranged from 71.1 to 162.0 nGy h⁻¹. The radium equivalent (R_eq) and the external hazard index (H_ex), which resulted from the natural radionuclides in soil, were also calculated and found to vary from 149.4 to 351.8 Bq kg⁻¹and from 0.40 to 0.95 respectively. These values in Upper Siwaliks area were compared with that from the adjoining areas of Punjab. The radium equivalent activities in all the soil samples were lower than the limit (370 Bq kg⁻¹) set in the Organization for Economic Cooperation and Development (OECD) report and the dose equivalent was within the safe limit of 1 mSv y⁻¹.