Radioecological Impact Research Articles

Assessment of marine radiological impact after an hypothetical nuclear accident in Eastern Mediterranean Sea

The consequences after an hypothetical nuclear accident at the Akkuyu Nuclear Power Plant in the region of Eastern Mediterranean Sea are presented. The dispersion of the radioactive plume in the sea is simulated applying a regional hydrodynamic/Lagrangian drift model and the radioecological impact is estimated after the release of 137Cs, 238Pu and 131I. The doses to marine biota and the human habitants of the affected regions are presented, while the sensitivity analysis of the results revile the most vulnerable features of this marine environment.

Risk analysis of radioecological effect of e-waste lead (Pb) content on life forms

Electronic waste (e-waste) has been proven to pollute the soil, air, and groundwater significantly. Aside from the physical effect of coming in contact with pollution, the radioecological impact of the pollution may be dangerous either directly or indirectly to persons living at the source of pollution. In this study, the lead (Pb) pollution from e-waste was used to calculate several organisms’ radioecological parameter. It is was observed that there was a moderate reduction in the number of plants with leaves (22%), a major reduction in cumulative stem growth (43% the control value), a severe increase in the number of chlorophyll mutations, severe changes in leaf colour (4.9-fold), and a major increase in mortality for all organism. It is recommended that landfill areas where e-wastes are dumped be excavated 9 m depth as a corrective measure to reduce the negative outcome on landfill workers.

Atmospheric discharge of 14C from the Tokai reprocessing plant: comprehensive chronology and environmental impact assessment

Quantitative evaluation of the atmospheric discharge of radiocarbon (14C) is of primary importance for accurately assessing the radioecological impact of the operation of the Tokai reprocessing plant (TRP). However, monitoring the atmospheric 14C discharge was not conducted at the TRP prior to October 1991. The main purpose of this study was to establish the chronology of atmospheric 14C discharges for the entire operation period (1977–2014). We found a strong correlation between the 14C discharge and spent fuel reprocessing data obtained after October 1991; we used this correlation to estimate the monthly 14C discharges in the 1977–1991 period. The total amount of atmospheric 14C discharge was estimated at 7741 ± 217 GBq for the entire period, with the largest annual discharge of 978 GBq in 1992. Tree-ring 14C analysis and model calculations using the established discharges were conducted to assess the excess 14C concentrations around the TRP in the past. The results suggested that the excess 14C concentrations were <45 Bq kg−1 C and the annual effective dose via the atmosphere–rice ingestion pathway was as low as 1.2 μSv y−1, indicating no significant radioecological impact of atmospheric 14C discharges from the TRP.

Health and ecological hazards due to natural radioactivity in soil from mining areas of Nasarawa State, Nigeria

Nasarawa State is located in north central Nigeria and it is known as Nigeria's home of solid minerals. It is endowed with barite, copper, zinc, tantalite and granite. Continuous releases of mining waste and tailings into the biosphere may result in a build-up of radionuclides in air, water and soil. This work therefore aims to measure the activity concentration levels of primordial radionuclides in the soil/sediment samples collected from selected mines of the mining areas of Nasarawa State. The paper also assesses the radiological and radio ecological impacts of mining activities on the residents of mining areas and their environment. The activity concentrations of primordial radionuclides (226Ra, 232Th and 40K) in the surface soils/sediment samples were determined using sodium iodide-thallium gamma spectroscopy. Seven major mines were considered with 21 samples taken from each of the mines for radiochemistry analysis. The human health hazard assessment was conducted using regulatory methodologies set by the United Nations Scientific Committee on the Effects of Atomic Radiation, while the radio ecological impact assessment was conducted using the ERICA tool v. 1.2. The result shows that the activity concentrations of 40K in the water ways of the Akiri copper and the Azara barite mines are 60 and 67 % higher than the world average value for 40K, respectively. In all mines, the annual effective dose rates (mSv y−1) were less than unity, and a maximum annual gonadal dose of 0.58 mSv y−1 is received at the Akiri copper mine, which is almost twice the world average value for gonadal dose. The external hazard indices for all the mines were less than unity. Our results also show that mollusc-gastropod, insect larvae, mollusc-bivalve and zooplankton are the freshwater biotas with the highest dose rates ranging from 5 to 7 µGy h−1. These higher dose rates could be associated with zinc and copper mining at Abuni and Akiri, respectively. The most exposed terrestrial reference organisms are lichen and bryophytes. In all cases, the radio ecological risks are not likely to be discernible. This paper presents a pioneer data for ecological risk from ionizing contaminants due to mining activity in Nasarawa State, Nigeria. Its methodology could be adopted for future work on radioecology of mining.

Consequences of radioactive releases into the sea resulting from the accident at the Fukushima Dai-ichi nuclear power plant - Evolution of expert investigation according to the data available

The accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011 led to an unprecedented direct input of artificial radioactivity into the marine environment. The Institute for Radioprotection and Nuclear Safety was requested by the French authorities to investigate the radioecological impact of this input, in particular the potential contamination of products of marine origin used for human consumption. This article describes the close link between the responses provided and the availability of the data, as well as their nature and ability to meet the requirements of expert investigation. These responses were needed: (i) to evaluate the inputs of radionuclides into the marine environment, (ii) to understand their dispersion in seawater, and (iii) to estimate their transfer to the biota and sediments. Three phases can be distinguished which characterise these processes during the accident and post-accident periods. The first phase corresponds to an emergency phase during which no measurements were available on samples from the marine environment. It involved the formulation of hypotheses based solely on the expertise of the Institute for Radioprotection and Nuclear Safety. The second phase started when the Japanese authorities provided measurements of the concentrations of radionuclides in seawater. Although these data were not yet adapted to addressing the problems of radioecology, the scenarios could then be refined and the estimates developed in more detail. During the third phase, the accumulation of data over the course of time made it possible to study the phenomena in an appropriate way. The chronology of the events shows that it is essential to have (i) significant measurements of concentration from samples collected in the various matrices of the marine environment, regularly updated and sufficiently well-documented, (ii) samples of seawater collected at the earliest opportunity as close as possible to the damaged site to characterise the source term, and (iii) a numerical tool allowing rapid modelling of the dispersion of radionuclides in seawater, as well as their transfer to sediments and the biota, ultimately for the purpose of estimating the dose to humans.

Radioecological evaluation (spatial and temporal variation) of the planktonic microorganisms in the Antas Reservoir, Caldas, Minas Gerais, Brazil

The Antas Reservoir (AR) receives treated effluents coming from the acid drainage of uranium ore from the Ore Treatment Unit?Brazilian Nuclear Industries (UTM-INB) plant located in Caldas, Minas Gerais, Brazil. This study was conducted in order to determine the possible radioecological impact caused by discharges of the treated liquid effluent from the UTM into the reservoir. Biological and physicochemical variables were evaluated in the present study. Sampling in the AR (Cab, P41, P14S and P14F points) took place during the dry winter (July 2006) and rainy summer seasons (February 2007). Each day, samples were collected four times (6:00 am, 12:00 noon, 6:00 pm and 12:00 midnight). The average trophic state index values obtained for samples in the dry and rainy periods allowed the areas to be classified as oligotrophic and mesotrophic, respectively. Chemical parameters indicated failures in the nuclear facility effluent treatment system, showing that effluents discharged at P41 do not agree with the standards that have been established by the Brazilian current legislation for Class II water. These results agreed with biological analyses, since P41 has the lowest density values for ciliated protozoa, indicating possible environmental impacts on the ecosystem due to the release of effluents by the mining company.

Chemical composition of 14C in airborne release from the Tokai reprocessing plant, Japan

Fuel reprocessing plant is one of the most important sources of anthropogenic (14)C in the environment. A method was developed to determine the amount and chemical composition of airborne (14)C release from the Tokai reprocessing plant, Japan. Effluent monitoring using this method showed most of the (14)C is released in CO(2) form and the ratio of (14)C in hydrocarbons to the total is less than 3%, not depending on the type of fuel reprocessed. This finding would provide improved understanding on dynamical behaviour of (14)C in the environment and assessment of radioecological impact from nuclear fuel cycle.

Characterization of uranium and plutonium containing particles originating from the nuclear weapons accident in Thule, Greenland, 1968

To improve long-term radioecological impact assessment for the contaminated ecosystem of Bylot Sound, Greenland, U and Pu containing particles have been characterized with respect to particle size, elemental distribution, morphology and oxidation states. Based on scanning electron microscopy with XRMA, particles ranging from about 20 to 40 μm were isolated. XRMA and μ-XRF mapping demonstrated that U and Pu were homogeneously distributed throughout the particles, indicating that U and Pu have been fused. Furthermore, μ-XANES showed that U and Pu in the particles were present as mixed oxides. U was found to be in oxidation state IV whereas Pu apparently is a mixture of Pu(III) and Pu(IV). As previous assessments are based on PuO 2 only, revisions should be made, taking Pu(III) into account.

Environmental characterization and radio-ecological impacts of non-nuclear industries on the Red Sea coast

The Red Sea is a deep semi-enclosed and narrow basin connected to the Indian Ocean by a narrow sill in the south and to the Suez Canal in the north. Oil industries in the Gulf of Suez, phosphate ore mining activities in Safaga—Quseir region and intensified navigation activities are non-nuclear pollution sources that could have serious radiological impacts on the marine environment and the coastal ecosystems of the Red Sea. It is essential to establish the radiological base-line data, which does not exist yet, and to investigate the present radio-ecological impact of the non-nuclear industries to preserve and protect the coastal environment of the Red Sea. Some natural and man-made radionuclides have been measured in shore sediment samples collected from the Egyptian coast of the Red Sea. The specific activities of 226Ra and 210Pb ( 238U) series, 232Th series, 40K and 137Cs (Bq/kg dry weight) were measured using gamma ray spectrometers based on hyper-pure germanium detectors. The specific activities of 210Po ( 210Pb) and uranium isotopes ( 238U, 235U and 234U) (Bq/kg dry weight) were measured using alpha spectrometers based on surface barrier (PIPS) detectors after radiochemical separation. The absorbed radiation dose rates in air (nGy/h) due to natural radionuclides in shore sediment and radium equivalent activity index (Bq/kg) were calculated. The specific activity ratios of 228Ra/ 226Ra, 210Pb/ 226Ra, 226Ra/ 238U and 234U/ 238U were calculated for evaluation of the geo-chemical behaviour of these radionuclides. The average specific activity of 226Ra ( 238U) series, 232Th series, 40K and 210Pb were 24.7, 31.4, 427.5 and 25.6 Bq/kg, respectively. The concentration of 137Cs in the sediment samples was less than the lower limit of detection. The Red Sea coast is an arid region with very low rainfall and the sediment is mainly composed of sand. The specific activity of 238U, 235U and 234U were 25.3, 2.9 and 25.0 Bq/kg. The average specific activity ratios of 226Ra/ 228Ra, 210Pb/ 226Ra and 234U/ 238U were 1.67, 1.22 and 1.0, respectively. The relationship between 226Ra/ 228Ra activity ratio and sample locations along the coastal shoreline indicates the increase of this ratio in the direction of the Shuqeir in the north and Safaga in the south where the oil exploration and phosphate mining activities are located. These activities may contribute a high flux of 226Ra. The concentration and distribution pattern of 226Ra in sediment can be used to trace the radiological impact of the non-nuclear industries on the Red Sea coast.

Derivation of a screening methodology for evaluating radiation dose to aquatic and terrestrial biota

The United States Department of Energy (DOE) currently has in place a radiation dose standard for the protection of aquatic animals, and is considering additional dose standards for terrestrial biota. These standards are: 10 mGy/d for aquatic animals, 10 mGy/d for terrestrial plants, and, 1 mGy/d for terrestrial animals. Guidance on suitable approaches to the implementation of these standards is needed. A screening methodology, developed through DOE’s Biota Dose Assessment Committee (BDAC), serves as the principal element of DOE’s graded approach for evaluating radiation doses to aquatic and terrestrial biota. Limiting concentrations of radionuclides in water, soil, and sediment were derived for 23 radionuclides. Four organism types (aquatic animals; riparian animals; terrestrial animals; and terrestrial plants) were selected as the basis for development of the screening method. Internal doses for each organism type were calculated as the product of contaminant concentration, bioaccumulation factor(s) and dose conversion factors. External doses were calculated based on the assumption of immersion of the organism in soil, sediment, or water. The assumptions and default parameters used provide for conservative screening values. The screening methodology within DOE’s graded approach should prove useful in demonstrating compliance with biota dose limits and for conducting screening assessments of radioecological impact. It provides a needed evaluation tool that can be employed within a framework for protection of the environment.

Radioecological impact from radionuclide releases into the rivers

Absract. The radiological impacts from radionuclide releases into Techa, and Yenisei Rivers in Russia are discussed. The dose assessments for human and natural biota are calculated using the methodology of multiple pathways of exposure. In the Mayak complex area the collective dose to the Techa River population during 19491956 was 6,200 man-Sv. The collective dose from radioactive discharges of the Krasnoyarsk complex into Yenisei River during the period 1958-1991 was about 1,200 man-Sv. A major contributor to this dose was consumption of the fish from Yenisei River (about 70 %). The doses to the natural biota are considerably higher than those to humans by a factor of 10-1000. This difference is most pronounced in the periods of significant radioactive releases. Especially high levels of exposure to biota were demonstrated for Techa River in the period of maximum discharges of radionuclides. A dose rate level of 10 mGy/day to natural biota was exceeded.

Spatial and temporal evolution of the levels of tritium in the Tagus river in its passage through Caceres (Spain) and the Alentejo (Portugal)

This work is the result of a collaboration between Spanish and Portuguese laboratories. The specific objective was to quantify the time evolution during 1994, 1995 and 1996 of the radioecological impact of the liquid releases of 3H from the Almaraz Nuclear Power Plant (ANPP) in the section of the Tagus River corresponding to Cáceres province in Spain and the Alentejo region in Portugal. We found that the temporal evolution of the levels of tritium depends on the management of the water held in the cooling reservoir of the ANPP and the presence of the dams that exist along the river. This management regime has a 12-month period. Also the movement of the mass of tritiated water (HTO) downriver was much faster during 1996 than 1995 or 1994 due to the hydrological differences between those years and consequently to the different amounts of water transferred between the reservoirs of the dams. From the hypothesis that hydrodynamically it is impossible to differentiate tritiated water from non-tritiated water, a model was constructed that satisfactorily reproduces the temporal evolution of the 3H in the zone of the Tagus River in which the exchange of water takes place, with the cooling reservoir of the Almaraz Nuclear Power Plant.

Radioecological Impact of the French Nuclear Power Plants on the Marine Environment

Since the end of the 1970s a global method has been developed and improved to characterise the radioecological impact of French nuclear power plants (PWRs) on the marine ecosystems. The environment of every nuclear plant is examined yearly, in addition to special studies carried out before plant operations begin and after each period of ten years. Three nuclear power plants are situated on the Channel coast (Flamanville, Paluel, Penly) and one on the North Sea coast (Gravelines). Near the power plants local radioecological impact is measurable and is essentially due to 58 Co, 60 Co and 110 Ag m . The monitoring of artificial gamma-emitter radioactivity in bioindicators (Fucus sp.) reveals the overall decline in releases from the four power stations in question ( 58 Co, 60 Co and 110 Ag m ) as well as the more marked decrease in relation to the reprocessing plant at La Hague ( 106 Ru, 60 Co, 125 Sb, 241 Am).