Distribution of (226)Ra-(210)Pb-(210)Po in marine biota and surface sediments of the Red Sea, Sudan

Activity concentration levels and ratios of (226)Ra, (210)Pb and (210)Po are presented in multicellular marine algae, molluscs, coral as well as in surface marine sediments collected from the shallower waters of the fringing reefs area extending towards north and south (Flamingo bay) of PortSudan harbour, Sudan. The analyses were performed adopting alpha-spectrometry, liquid scintillation and Cerenkov counting techniques. Surface sediments from this coastal region are poor in their radioactivity content in contrast to similar data reported from different coastal areas around the globe. There is surface enrichment of (210)Pb and (210)Po with respect to their progenitor (226)Ra as it is evident from the activity ratios of (210)Pb/(226)Ra (3.03+/-1.79) and (210)Po/(226)Ra (2.23+/-1.56). Among marine plants and animals investigated, the green algae species, Halimeda, and coral species, Favites, show substantial concentration of radium at 8.2Bq/kg and 21.9Bq/kg dry weight, respectively. Similarly, the highest concentration of (210)Po was met in Favites at 38.7Bq/kg followed by brown algae, Cystoseria sp., at 32.6Bq/kg. There is no variation seen among algal species for (210)Pb uptake, however, converse to radium and polonium, Favites (coral) was found to contain the minimum concentration of lead (3.88Bq/kg). In most species there is preferential accumulation of polonium over its parent radium as indicated by (210)Po:(226)Ra activity ratio with Cystoseria (brown algae) showing the highest value at 8.81. On the other hand, (210)Po:(210)Pb activity concentration ratio revealed that coral species Favites (9.97) and the brown algae Sargassum (1.85) have a greater tendency to accumulate (210)Po over (210)Pb, while in the rest of species; this ratio is less than unity.     

The temporal variations of (7)Be, (210)Pb and (210)Po in air in England

We have conducted measurements of naturally occurring radionuclides (7)Be, (210)Pb and (210)Po in air at ground level at Chilton, Oxfordshire, England. The sampling and analysis regime for the latter two isotopes has been optimised to minimise uncertainties in measurement due to decay of (210)Po and in-growth of (210)Pb during the sampling and analysis period. Analysis times were reduced by using Cerenkov counting to assay the (210)Bi daughter of (210)Pb. Monthly data collected over a four-year period are presented and discussed. (7)Be activity concentrations appear to peak in spring. (210)Pb activity concentrations also follow a seasonal trend reflecting different (222)Rn emanation rates from soil during winter and summer. Data for (210)Po show no such trend.     

Predictive model for the (14)C radioactivity in a plant following an exposure to airborne (14)CO(2) gas

This paper provides details of a dynamic compartment model for estimating the (14)C radioactivity in an agricultural plant exposed to an amount of airborne (14)CO(2) gas. The plant, in the model, is divided into two compartments, the plant body (shoot and root) and ears, to predict the radioactivity of different parts of a plant. The carbon transports from, to and between the compartments are described by the processes of a photosynthesis, respiration, and translocation. The carbon transport fluxes of these processes are determined from the growth rates of a plant, which are usually easily attained. The model predictions showed that the present model could converge to a region where the specific activity model is applicable when the elapsed exposure time was extended up to the harvest time of a plant. The (14)C activity of a plant was greatly affected by the elapsed exposure time, the developmental stages of a plant at an exposure time, and the airborne (14)C activity during an exposure. It was expected that the peak of the ears' (14)C activity appeared when the exposure time was close to the ears-maturity date. The model predictions agreed reasonably well with the measured (14)C radioactivity of the rice plants that were artificially exposed to (14)CO(2) of a high (14)C source for a short period of time in an exposure box.     

A model for the bioaccumulation of (99)Tc in lobsters (Homarus gammarus) from the West Cumbrian coast

A biokinetic model is presented that simulates the uptake and release of (99)Tc by the European lobster (Homarus gammarus). This organism is of significant radioecological interest since lobsters, in contrast to most other organisms, have a high affinity for (99)Tc. The model is designed to represent annually averaged (99)Tc concentrations in lobsters from the Cumbrian coast, where significant levels of (99)Tc have been released under authorisation by the nuclear fuel reprocessing plant at BNFL Sellafield.This paper describes the construction of the model, how it was calibrated using data from published literature, and preliminary results indicating that model output agrees well with the available monitoring data. Given that this model successfully combines laboratory and field data, this research could potentially make a significant contribution to the field, as, to date, it has been difficult to predict and explain concentrations of (99)Tc in lobsters.     

Factors influencing ambient concentrations of (210)Pb and (7)Be over the city of Edinburgh (55.9 degrees N, 03.2 degrees W)

Concentrations of (210)Pb and (7)Be in air were continuously monitored, using a high-volume air sampler and a high-resolution gamma-ray spectrometer, during the period of July 2002 to June 2003 at the University of Edinburgh 55.9 degrees N, 03.2 degrees W. The time series of both radio-isotopes show seasonality, dependence on air-mass origin, residence time and precipitation. Surface air concentrations of (210)Pb and (7)Be ranged from 0.01 to 0.74 mBq m(-3) and 0.63-6.54 mBq m(-3), respectively. The measurements indicate that the average concentrations of both (210)Pb and (7)Be in surface air were 0.21+/-0.01 and 2.50+/-0.04 mBq m(-3), respectively; which agrees closely with the corresponding values reported for coastal air measurements in Europe.     

Simulating transport of non-Chernobyl (137)Cs and (90)Sr in the North Atlantic-Arctic region

The spatial and temporal distributions of the anthropogenic radionuclides (137)Cs and (90)Sr, originating from nuclear bomb testing and the Sellafield reprocessing plants in the Irish Sea, are simulated using a global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The physical model is forced with daily atmospheric re-analysed fields for the period 1950 to present. Comparison of temporal evolution of observed and simulated concentrations of (137)Cs have been conducted for the regions east of Scotland, west of central Norway and at the entrance of the Barents Sea. It follows that the radionuclides from the Sellafield discharge reach the Barents Sea region after 4-5 years, in accordance with observations. The simulation provides a detailed distribution and evolution of the radionuclides over the integration time. For the Atlantic waters off the coast of Norway and in the southern Barents Sea, the atmospheric fallout dominates over the Sellafield release up to the mid 1960s and from the early 1990s, whereas Sellafield is the main source for the two radionuclides in the 1970s and 1980s. It is furthermore argued that model systems like the one presented here can be used for future prediction of radioactive contaminations in the Nordic Seas and the Arctic Ocean, for instance under various global warming scenarios.     

The effect of pollutants (heavy metals and diesel fuel) on the respiratory activity of constructozems (artificial soils)

Young (1 month old) and mature (2 years old) constructozems (artificial soils) were supplemented with individual heavy metal salts or diesel fuel at different concentrations. The polluted and control constructozem variants were incubated and sampled at different time points to determine microbial biomass carbon (C_mic) and microbial respiration (MR). These parameters were found to be almost twice higher in the young than in the mature constructozem, with all pollutants causing an increase in C_mic, MR, and MR/C_mic = qCO₂ values. The pollutant type had an effect on MR and qCO₂ variances, and the time of exposure, on C_mic. The qCO₂ value showed a strong positive correlation with pollutant concentrations, allowing this parameter to be regarded as a suitable indicator of urban environmental pollution.     

New perspectives on the energy return on (energy) investment (EROI) of corn ethanol

Research on corn ethanol is overly focused on whether corn ethanol is a net energy yielder and, consequently, has missed some other fundamental issues, including (1) whether there is significant error associated with current estimates of the EROI of corn ethanol, (2) whether there is significant spatial variability in the EROI of corn ethanol production, (3) whether yield increases will translate linearly to increases in EROI, (4) the extent to which assumptions about co-product credits impact the EROI of corn ethanol, and (5) how much of the ethanol production from biorefineries is net energy. We address all of these concerns in this research by: (1) performing a meta-error analysis of the calculation of EROI, (2) calculating the EROI for 1,287 counties across the United States, and (3) performing a sensitivity analysis for the values of both yield and co-products within the calculation of EROI. Our results show that the average EROI calculated from the meta-error analysis was 1.07 ± 0.2, meaning that we are unable to assert whether the EROI of corn ethanol is greater than one. The average EROI calculated across 1,287 counties in our spatial analysis was 1.01, indicating that the literature tended to use optimal values for energy inputs and outputs compared to the average conditions across the Unites States. Increases in yield had a trivial impact on EROI, while co-product credits had a large impact on EROI. Based on our results from the spatial analysis and the location of biorefineries across the United States, we conclude that the net energy supplied to society by ethanol is only 0.8% of that supplied from gasoline. Recent work indicates that only energy sources extracted at EROIs of 3:1 or greater have the requisite net energy to sustain the infrastructure of the transportation system of the United States. In light of this work, we conclude that production of corn ethanol within the United States is unsustainable and requires energy subsidies from the larger oil economy.     

Soil-water distribution coefficients and plant transfer factors for (134)Cs, (85)Sr and (65)Zn under field conditions in tropical Australia

Measurements of soil-to-plant transfer of (134)Cs, (85)Sr and (65)Zn from two tropical red earth soils ('Blain' and 'Tippera') to sorghum and mung crops have been undertaken in the north of Australia. The aim of the study was to identify factors that control bioaccumulation of these radionuclides in tropical regions, for which few previous data are available. Batch sorption experiments were conducted to determine the distribution coefficient (K(d)) of the selected radionuclides at pH values similar to natural pH values, which ranged from about 5.5 to 6.7. In addition, K(d) values were obtained at one pH unit above and below the soil-water equilibrium pH values to determine the effect of pH. The adsorption of Cs showed no pH dependence, but the K(d) values for the Tippera soils (2300-4100 ml/g) exceeded those for the Blain soils (800-1200 ml/g) at equilibrium pH. This was related to the greater clay content of the Tippera soil. Both Sr and Zn were more strongly adsorbed at higher pH values, but the K(d) values showed less dependence on the soil type. Strontium K(d)s were 30-60 ml/g whilst Zn ranged from 160 to 1630 ml/g for the two soils at equilibrium pH. With the possible exception of Sr, there was no evidence for downward movement of radionuclides through the soils during the course of the growing season. There was some evidence of surface movement of labelled soil particles. Soil-to-plant transfer factors varied slightly between the soils. The average results for sorghum were 0.1-0.3 g/g for Cs, 0.4-0.8 g/g for Sr and 18-26 g/g for Zn (dry weight) with the initial values relating to Blain and the following values to Tippera. Similar values were observed for the mung bean samples. The transfer factors for Cs and Sr were not substantially different from the typical values observed in temperate studies. However, Zn transfer factors for plants grown on both these tropical soils were greater than for soils in temperate climates (by more than an order of magnitude). This may be related to trace nutrient deficiency and/or the growth of fungal populations in these soils. The results indicate that transfer factors depend on climatic region together with soil type and chemistry and underline the value of specific bioaccumulation data for radionuclides in tropical soils.     

Non-ferrous metals (Pb, Cu, Zn) needs and city development: the Paris example (1815–2009)

The aim of this study is to explore the urban and/or industrial needs for non-ferrous metals (lead (Pb), copper (Cu) and zinc (Zn)) of Paris (France), a highly developed city conurbation, from the beginning of the nineteenth century to the present. Pb was necessary for the development of urban networks (Pb pipes), Zn for Parisian roofs and Cu for the development of boiler making and electricity. This study is based on economic statistics and shows that the situation evolved from a city transforming ores, having its smelters and transforming metal into goods, to a city where metal smelting has been more or less quickly banned, and where only a small activity of metal transformation into metal-containing goods remains. The patterns of the three metals showed slight differences. The deindustrialization of Paris is also accompanied by a change of the supplying areas over time. Ores were always imported from abroad, because of the lack of French non-ferrous metal mines. But foundries, which were first abroad, had developed in France between the late nineteenth and late twentieth century and were again found abroad at the end of the twentieth century. The transformation of metal into goods left Paris to the benefit of other parts of France first, then of abroad, over time. In a second part, the evaluation of Pb consumption per capita in Paris conurbation shows that Pb needs of Paris conurbation were higher than those of France in the nineteenth century. Then, the Paris demand was satisfied and it became lower than that of France. Both the deindustrialisation of Paris conurbation and its lower needs led to a decrease in the relative weight of Paris for non-ferrous metals, compared to other parts of France.     

Comparative accumulation of (109)Cd and (75)Se from water and food by an estuarine fish (Tetractenos glaber)

Few data are available on the comparative accumulation of metal(loid)s from water and food in estuarine/marine fish. Smooth toadfish (Tetractenos glaber), commonly found in estuaries in south-eastern Australia, were separately exposed to radio-labelled seawater (14kBqL(-1) of (109)Cd and 24kBqL(-1) of (75)Se) and food (ghost shrimps; Trypaea australiensis: 875Bqg(-1)(109)Cd and 1130Bqg(-1)(75)Se) for 25 days (uptake phase), followed by exposure to radionuclide-free water or food for 30 days (loss phase). Toadfish accumulated (109)Cd predominantly from water (85%) and (75)Se predominantly from food (62%), although the latter was lower than expected. For both the water and food exposures, (109)Cd was predominantly located in the gut lining (60-75%) at the end of the uptake phase, suggesting that the gut may be the primary pathway of (109)Cd uptake. This may be attributed to toadfish drinking large volumes of water to maintain osmoregulation. By the end of the loss phase, (109)Cd had predominantly shifted to the excretory organs - the liver (81%) in toadfish exposed to radio-labelled food, and in the liver, gills and kidney (82%) of toadfish exposed to radio-labelled water. In contrast, (75)Se was predominantly located in the excretory organs (gills, kidneys and liver; 66-76%) at the end of the uptake phase, irrespective of the exposure pathway, with minimal change in percentage distribution (76-83%) after the loss phase. This study emphasises the importance of differentiating accumulation pathways to better understand metal(loid) transfer dynamics and subsequent toxicity, in aquatic biota.     

Exploring the impact of sustainability (ESG) disclosure on firm value and financial performance (FP) in airline industry: the moderating role of size and age

Environment, Development and Sustainability - This study aims at exploring the impact of ESG scores on the value and FP of firms in the airline industry. The potential moderating role of firm size...     

Assessment of the uncertainties in the Radiological Protection Institute of Ireland (RPII) radon measurements service

The RPII radon (Rn) laboratory holds accreditation for the International Standard ISO/IEC 17025. A requirement of this standard is an estimate of the uncertainty of measurement. This work shows two approaches to estimate the uncertainty. The bottom-up approach involved identifying the components that were found to contribute to the uncertainty. Estimates were made for each of these components, which were combined to give a combined uncertainty of 13.5% at a Rn concentration of approximately 2500Bqm(-3) at the 68% confidence level. By applying a coverage factor of k=2, the expanded uncertainty is +/-27% at the 95% confidence level. The top-down approach used information previously gathered from intercomparison exercises to estimate the uncertainty. This investigation found an expanded uncertainty of +/-22% at approximately 95% confidence level. This is good agreement for such independent estimates.     

High (210)Po atmospheric deposition flux in the subtropical coastal area of Japan

Bulk atmospheric deposition fluxes of (210)Po and (210)Pb were measured at three coastal regions of Japan, the Pacific Ocean coastal area of the Japanese mainland (Odawa Bay), the Chinese continental side of Japanese coastal area (Tsuyazaki), and an isolated island near Okinawa (Akajima). Wet and dry fallout collectors were continuously deployed from September 1997 through August 1998 for periods of 3 to 31 days depending on the frequency of precipitation events. Annual (210)Pb deposition fluxes at Odawa Bay (35 degrees N 139 degrees E), Tsuyazaki (33 degrees N 130 degrees E) and Akajima (26 degrees N 127 degrees E) were 73.3+/-8.0, 197+/-35 and 78.5+/-8.0 Bqm(-2)y(-1), respectively. Higher (210)Pb deposition was observed at the Chinese continental side of Japanese coast than at the Pacific Ocean coastal site. The high (210)Pb atmospheric flux at the Chinese continental side coast was thought to be attributable to (222)Rn-rich air-mass transport from the Chinese continent during the winter monsoon. In contrast, the annual (210)Po deposition fluxes at the three study sites were 13.0+/-2.3 (Odawa Bay), 21.9+/-4.4 (Tsuyazaki) and 58.4+/-7.7 (Akajima)Bqm(-2)y(-1), respectively, indicating unusual high (210)Po deposition at Akajima during winter. Anomalous unsupported (210)Po input was observed during summer 1997, suggesting unknown source of (210)Po at this area.     

Microbial removal of uranyl by sulfate reducing bacteria in the presence of Fe (III) (hydr)oxides

Microbiological reduction of uranyl by sulfate reducing bacteria (SRB) has been proposed as a promising method for removal of radionuclide from groundwater. In this study, we examined the effect of two naturally occurring Fe(III) (hydr)oxides, hematite and goethite, on the bioreduction of U(VI) by a mixed culture of SRB via laboratory batch experiments. The biogenic precipitate from U(VI) bioreduction was determined using X-ray absorption near edge structure (XANES) analysis, showing a typical feature of uraninite (UO₂). In the presence of either hematite or goethite-containing Fe(III) ranging from 10 to 30 mM, the reduction of U(VI) was retarded by both minerals and the retardatory effect was enhanced with increasing amount of Fe(III) (hydr)oxide. When exposed to a mixture of hematite and goethite with the total Fe(III) kept constant at 20 mM, the retardatory effect on U(VI) reduction by the minerals were directly correlated with the fraction of hematite present. A slow increase in U(VI) concentration was also found in all Fe(III) (hydr)oxide treatments after 10-13 days, accompanied by the release of Fe(II) into the solution. The presence of Fe(III) (hydr)oxide can cause the eventual incomplete bioreduction of U(VI). However, it was not the case for the control without minerals. When mixing biogenic uraninite with hematite or goethite without SRB, Fe(II) was also detected in the solution. These findings suggest that the U(VI) remobilization after 10～13 days may be due to reoxidation of the uraninite by the solid-phase Fe(III) (hydr)oxide.     

Effect of liming on the behaviour of (90)Sr and (137)Cs in a lake ecosystem

Liming of lakes is considered one possible remedial action to reduce the accumulation of radionuclides into fish in the case of a radiological accident. These responses were tested in field conditions in a small acidified lake that was divided into two parts: one limed with CaCO₃ and the other half left as an unlimed control. The transfer of ⁹⁰Sr from water into fish decreased on average by 50% during the first year after liming. However, at the same time the ⁹⁰Sr concentration in water increased, reaching a maximum within 6 months after liming. Approximately 50% more ⁹⁰Sr was detected in water in the limed part of the lake than on control side during the first year. ⁹⁰Sr was most probably released from the sediment as the Ca concentration and pH of the water increased. As a result of these two processes, which counterbalanced each other (increased release of ⁹⁰Sr into water from sediment and decreased transfer of ⁹⁰Sr from water into fish), the ⁹⁰Sr concentration in fish did not notably differ between the limed and control sides of the lake. Liming may only be suitable as a remedial action if carried out immediately after a radiological accident, before significant amounts of radionuclides have been deposited in lake sediments. In the case of ¹³⁷Cs, the effect of liming was less pronounced. ¹³⁷Cs activity concentration in water increased in the first year by 20% and uptake by fish decreased by 20%.     

Comparative analysis of (239)Pu, (137)Cs, (210)Pb and (40)K spatial distributions in the top soil layer at the Baltic coast

This paper presents the results of an investigation into the spatial distribution of radionuclides of artificial ((239,240)Pu, (137)Cs) and natural ((210)Pb, (40)K) origins in the upper (0-5 cm) soil layers on the Baltic coastline of Lithuania ( approximately 5 km(2) area). The samples were analysed by gamma ray spectrometry and combined radiochemical procedures. The highest (210)Pb, (239,240)Pu and (137)Cs activity concentrations were determined in the forest samples, whereas (40)K activity was rather homogeneous across the study area. Relatively high (239,240)Pu and (40)K activity concentrations were determined along the surf zone. The (210)Pb and (137)Cs activity concentrations showed a gradual increase from the surf zone to the forest. The average activity concentrations of (239,240)Pu, (137)Cs, (210)Pb and (40)K in the beach and forest samples, respectively, were as follows: 0.32+/-0.08 and 0.74+/-0.14; 50+/-4 and 1190+/-50; 4.7+/-2.0 and 48+/-6; 186+/-15 and 216+/-17 Bq/kg.     

Radon concentrations in groundwaters of the Polish part of the Sudety Mountains (SW Poland)

In the course of researches into radon occurrence in the groundwaters of the Polish part of the Sudety Mountains, conducted in various research centres in Poland, almost 1000 radon concentration determinations have been collected. These results have given the basis for an attempt to characterise the groundwaters of this region with respect to radon content. Radon concentrations oscillated within the range of 0.2-1645 Bq/dm3, with the arithmetic mean at 240.0 Bq/dm3 and the geometric mean at 106.7 Bq/dm3. The largest number of radon concentrations found in the Sudetic groundwaters ranged between ca. 3-6 and 1000 Bq/dm3. The values over 1000 Bq/dm3 can be considered anomalously high. They constitute 3.9% of all the results and occur around six localities within different geological units of the Sudety Mountains. These are shallow circulation, low mineralised groundwaters, which outflow from gneisses and granites. In the face of the fact that from 12.8% to 72.7% (depending on the adopted norm of maximum radon concentration for drinking waters) of the examined waters cannot be drunk directly without removing at least part of the radon, and in the face of the possibility of recognizing as many as 63.5% of the waters as potentially medicinal, extensive research of radon geochemistry in the Sudety Mountains area should be urgently undertaken.     

A review of the ecological effects of radiofrequency electromagnetic fields (RF-EMF)

ObjectiveThis article presents a systematic review of published scientific studies on the potential ecological effects of radiofrequency electromagnetic fields (RF-EMF) in the range of 10 MHz to 3.6 GHz (from amplitude modulation, AM, to lower band microwave, MW, EMF).MethodsPublications in English were searched in ISI Web of Knowledge and Scholar Google with no restriction on publication date. Five species groups were identified: birds, insects, other vertebrates, other organisms, and plants. Not only clear ecological articles, such as field studies, were taken into consideration, but also biological articles on laboratory studies investigating the effects of RF-EMF with biological endpoints such as fertility, reproduction, behaviour and development, which have a clear ecological significance, were also included.ResultsInformation was collected from 113 studies from original peer-reviewed publications or from relevant existing reviews. A limited amount of ecological field studies was identified. The majority of the studies were conducted in a laboratory setting on birds (embryos or eggs), small rodents and plants. In 65% of the studies, ecological effects of RF-EMF (50% of the animal studies and about 75% of the plant studies) were found both at high as well as at low dosages. No clear dose–effect relationship could be discerned. Studies finding an effect applied higher durations of exposure and focused more on the GSM frequency ranges.ConclusionsIn about two third of the reviewed studies ecological effects of RF-EMF was reported at high as well as at low dosages. The very low dosages are compatible with real field situations, and could be found under environmental conditions. However, a lack of standardisation and a limited number of observations limit the possibility of generalising results from an organism to an ecosystem level. We propose in future studies to conduct more repetitions of observations and explicitly use the available standards for reporting RF-EMF relevant physical parameters in both laboratory and field studies.