The aim of this study was to assess the environmental radiological risk of coal ash and slag to terrestrial wildlife. The research site used in this study was a disposal site of coal ash and slag ...with enhaced content of uranium decay chain radionuclides. With the use of the ERICA Tool, total dose rates to wildlife and risk of resultant radiobiological effects were estimated. As input data for the assessment, experimental activity concentrations of 238U, 226Ra and 210Pb in coal ash and slag and best estimates of activity concentrations for related daughter radionuclides and 235U decay chain were used. Where possible, the experimental data for activity concentrations of 238U, 226Ra and 210Pb in plants and related concentration ratios were used. Results were compared to background dose rates, also estimated by the Tool. The Tool's assessment data indicated internal exposure as the prevalent exposure pathway with 226Ra and 210Po as the main dose contributors. Also, the contribution of 235U decay chain to the total dose rate was not negligible since for some organisms it represented up to 11% of the total dose rate. The risk of an occurrence of radiobiological effects in plants on the coal ash and slag disposal site can be considered negligible since the estimated total dose rates were below the screening dose of 10 μGyh−1 and near the dose rates estimated for plants in the control area. However, the estimated dose rates for reference animals and Lichen & Bryophytes were above the screening dose rate for most organisms and on average 13 times higher than the estimated background dose rates. At the given dose rates, an occurrence of different radiobiological effects could not be excluded for animals in close contact with coal ash and slag such as earthworms and small burrowing mammals. A separate assessment performed on an example of reference plants showed that the use of activity concentrations in organisms as input data can result in an order of magnitude smaller estimates of dose rates in comparison to activity concentration in coal and ash as input data. Our study highlighted the need for experimental data in radiological risk assessments to mitigate the conservatism of the ERICA Tool and its tendency to overestimate dose rates.
•The ERICA Tool was used for a radiological risk assessment of CAS to terrestrial wildlife.•Internal exposure was dominant with 226Ra and 210Po as the main dose contributors.•235U decay chain radionuclides contributed on average 7% to the total dose rates.•Different inputs to the Tool can result in an order of magnitude different outcomes.•Radiological risk to animals in close contact with CAS cannot be neglected.
The aim of this study was to provide baseline radioecological data for the temperate forest ecosystem in Plitvice Lakes National Park. Emphasis was placed on the determination of naturally occurring ...radionuclides since there is an acknowledged lack of data for these radionuclides in non-accident conditions in wildlife, even for bioindicator organisms. Activity concentrations of
238
U,
226
Ra,
210
Pb,
232
Th,
40
K,
134
Cs, and
137
Cs were measured by gamma spectrometry in soil and bioindicators: earthworms, conifer needles, mosses, and lichens. From the measured activity concentrations, concentration ratios were calculated to quantify the transfer of these radionuclides from soil to bioindicators. Our results show that soil activity concentrations are biased toward results from other studies conducted within the Dinaric mountain region. However, in moss and lichen samples, we measured higher activity concentrations of
226
Ra and lower activity concentrations of
40
K and
137
Cs in comparison to similar studies. Also, we estimated lower concentration ratios for all radionuclides from soil to these organisms, except for
210
Pb, in comparison to generic values. The transfer of
238
U was generally low for all of the bioindicator organisms. For conifer needles, a correlation was found between activity concentrations of
226
Ra and
137
Cs in soil and related concentration ratios. Correlation was also found between the activity concentration of
40
K in soil and transfer of
40
K and
137
Cs to mosses and lichens. A comparison with literature data highlighted the lack of
226
Ra related concentration ratios for conifer trees and especially for earthworms. Therefore, the results of this study could supplement the sparse data currently available on radionuclide background data in similar ecosystems and related soil-to-wildlife transfer of radionuclides. Dose rate assessments, performed by the ERICA Tool, estimated that 96% of the overall exposure of wildlife in the Park area is due to the background dose rates, while 0.06 μGy h
−1
on average can be attributed as an incremental dose rate from
134
Cs and
137
Cs.
This paper presents the results of long-term investigations of
Cs and
Cs activity concentrations in drinking water in the city of Zagreb for the period 1987–2018. The highest activity concentrations ...of both radio-nuclides were measured in 1987, decreasing exponentially ever since, while
Cs in several subsequent years fell under the detection limit. After the Fukushima Daiichi accident in 2011, the presence of
Cs in drinking water was detected again. The environmental residence time for
Cs was estimated to be 8.1 years in drinking water and 5.7 years in fallout. The correlation between
Cs in fallout and in drinking water is very good, and this indicates that fallout is the main source of water contamination. The observed
Cs/
Cs activity ratio in drinking water for the post-Chernobyl period was similar to the ratio found in other environmental samples. The estimation of annual effective doses received by the adult members of the Croatian population due to the intake of radiocaesium in drinking water showed quite small doses of 0.28 μSv in 1987 decreasing to 2.5 nSv in 2018, which indicated that drinking water was not a critical pathway for the transfer of radiocaesium to humans.
•Stationary diffusion model was used to describe phosphogypsum particle transfer.•Active electronic dosimeters ALARA were used to measure dose rates.•The mass concentration of particles was ...determined fiducially and realistically.•The model enabled to reduce the expenses and time of the measurements.
Phosphogypsum (PG), a waste product in phosphate fertilizer production, is characterized by technically enhanced natural radioactivity. The presented investigation was performed on a PG deposition site in Croatia. A new approach in the determination of the spread of PG particles from the deposition site into the environment based on the PG particle radioactivity measurements is suggested and explained. The stationary diffusion model was assumed and employed to describe long term PG particle transfer into the surroundings. The advantage of this method is that it requires a minimal number of measurement locations and offers a realistic and reliable distribution of PG particles. The mass concentration of PG particles decreased to the distance of about 3m, at most up to 10m from the deposition site edge. The results indicate that a unique mechanism of particle transport exists and the migration of PG particles by surface water is the dominant way of their spread. The particle current deduced from the measurements was very low, approximately 4.05×10−2kg/h, and the migration coefficient was approximately 1.69×10−5m2/h. The obtained results confirmed the initial hypothesis of the stationarity of the migration process, reached within about 6 years.
This study investigates multi-element composition of soil, mosses and mushrooms from a pristine temperate rainforest (Prašnik, Croatia). Additionally, the activity levels of natural (238U, 235U and ...232Th decay chains, 40K and 7Be) and anthropogenic (137Cs and 134Cs) radionuclides in the investigated soil samples, obtained by gamma spectrometry, provide baseline of environmental radioactivity levels in this area. The aim of investigation was to explore the uptake of metal(loid)s by bioindicator species (mosses, mushrooms) growing in a pristine environment characterized by naturally elevated concentration of metals. The calculated enrichment and bioaccumulation factors, correlations between different groups of elements and similar multi-element patterns in mosses, mushrooms and soil samples revealed the prevailing influence of the local substrate geochemistry on element concentrations in mosses and mushrooms. The results suggest atmospheric deposition of Bi, Cd and Pb, while radionuclide activities point to atmospheric fall-out (including global contamination by radiocaesium) and influence of the pedological substrate. The confined area of investigation, with limited variations in soil characteristics and geological composition, allowed clearer insight into the origin of metal(loid)s in mosses and mushrooms. On the other hand, using bioindicator species with different element uptake mechanisms enabled distinction between different sources of elements.
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•Multi-element composition of soil, mosses and mushrooms from a pristine forest.•Soil radioactivity levels (238U, 235U, 232Th, 40K, 7Be,137Cs, 134Cs) determined.•Element levels in mosses and mushrooms influenced by substrate geochemistry.•Indications of atmospheric deposition of Bi, Cd and Pb.
The long-term behaviour of ¹³⁷Cs activity concentrations in air and fallout has been studied in the city of Zagreb for the post-Chernobyl period (1986-2006) as a part of an extended monitoring ...program of radioactive contamination of human environment in Croatia. Annual mean ¹³⁷Cs activity concentrations in air and annual total deposition fluxes (wet plus dry) decreased from 2.8 x 10⁻⁴ Bq m⁻³ in September 1986 to 3.0 x 10⁻⁶ Bq m⁻³ in last quarter of 2006 and from 6,410 Bq m⁻² year⁻¹ in 1986 to 2 Bq m⁻² year⁻¹ in 2006 respectively. By fitting the measured ¹³⁷Cs activity concentrations to the theoretical curve the ecological half-lives of ¹³⁷Cs in air and fallout were estimated with respective values of 0.46 and 0.54 years for immediate post-Chernobyl period, increasing to 5.52 and 3.97 years afterwards. Using the data on ¹³⁷Cs activity concentrations in air and fallout total caesium deposition velocity of (3.34 ± 3.13) x 10⁻² ms⁻¹ was estimated with median value being 2.13 x 10⁻² ms⁻¹. Such relatively high ¹³⁷Cs deposition velocities compared with pre-Chernobyl ones, are characteristic for the post-Chernobyl period and, according to Stokes' settling law, indicate that the diameters of aerosol particles associated with ¹³⁷Cs originated from the Chernobyl accident are pretty large, i.e. >1 μm. ¹³⁴Cs/¹³⁷Cs activity ratio in fallout and in air has been found to be similar to the theoretically predicted values, initial value being about 0.5 and decreasing according to differential radioactive decay. The similar ratio has been observed in most of the other environmental samples.
Long-term investigations of radiocaesium activity concentrations in beef in the Republic of Croatia are presented. The radiocaesium levels in beef decreased exponentially and the effective ecological ...half-life of 137Cs was estimated to be 0.57±0.06 years for 1986–1990 period and 5.21±0.27 years for the 1991–2005 period. For 1986–1990 period, the effective ecological half-life of 134Cs in was estimated to be about 0.69±0.05 while 134Cs activity concentrations after year 1990 were below the detection limit of the instruments.
The 134Cs:137Cs activity ratio in beef has been found to be similar to the ratio that has been observed in other foodstuffs and environmental samples.
Radioecological sensitivity for beef meat, i.e., the transfer coefficient from fallout to sample was estimated to be 1.15× 10−2Bqykg−1/(Bqm−2).
For an adult member of Croatian population annual effective doses received by 134Cs and 137Cs intake due to consumption of beef are small, as per caput effective dose for the overall 1986–2005 period was estimated to be 24.6μSv. Consequently, after the Chernobyl accident beef consumption was not a critical pathway for the transfer of radiocaesium from fallout to humans in Croatia.
Long-term investigations of radiocaesium activity concentrations in carp in the Republic of Croatia are presented. The radiocaesium levels in carp decreased exponentially and the effective ecological ...half-life of
137Cs was estimated to be about 1 year during 1987–2002 and 5 years during 1993–2005.
The observed
134Cs:
137Cs activity ratio in carp was found to be similar to the ratio observed in other environmental samples.
The concentration factor for carp (wet weight) was estimated to be 128
±
74
L
kg
−1, which is in reasonable agreement with model prediction based on K
+ concentrations in water.
Estimated annual effective dose received by adult members of the Croatian population due to consumption of carp contaminated with
134Cs and
137Cs are small: per capita dose from this source during 1987–2005 was estimated to be 0.5
±
0.2
μSv.
Due to minor freshwater fish consumption in Croatia and low radiocaesium activity concentrations in carp, it can be concluded that carp consumption was not a critical pathway for the transfer of radiocaesium from fallout to humans after the Chernobyl accident.
Results of systematic, long-term measurements of (137)Cs activities in wheat for the period 1965-2003 are summarized. Radiocaesum fallout activities affect wheat activity concentrations, the ...coefficient of correlation being 0.91. In the observed period, the highest activity of (137)Cs deposited by fallout, 6321 Bq m(-2), was recorded in 1986, i.e., in the year of Chernobyl accident, causing peak (137)Cs activity concentration in wheat of 38.0 +/- 13.0 Bq kg(-1). After the Chernobyl nuclear accident the (134)Cs:(137)Cs activity ratio in wheat was approximately 0.5, and did not differ from the value found in other environmental samples. The transfer coefficient from (137)Cs fallout deposition to wheat was calculated to be 8.6 x 10(-3) Bq y kg(-1) per Bq m(-2), indicating the low transfer of radiocaesium from fallout to wheat. The upper limit for the collective effective dose for the Croatian population due to (137)Cs and (134)Cs ingestion by wheat and wheat products consumption for period 1965-2003 was estimated to be 665 person-Sv, the upper limit for the annual collective effective dose in 2003 being only about 0.061 person-Sv.
In this study, the influence of anthropogenic pollution on the aquatic environment of Plitvice Lakes National Park (PLNP) was investigated during 2011–2012 using a combination of chemical and ...cytogenetic analyses. Four groups of major contaminants (volatile organic compounds: benzene, toluene, ethylbenzene, and xylenes (BTEX); persistent organochlorine pollutants: organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs); major and trace elements; anthropogenic radionuclides (
90
Sr,
134
Cs, and
137
Cs) were determined in three aquatic compartments (water, sediment, fish). Mass fractions of inorganic constituents in different compartments reflected the geological background of the area, indicating their origin from predominantly natural sources. Levels of volatile and persistent organic compounds in water and fish, respectively, were very low, at levels typical for remote pristine areas. Analysis of anthropogenic radionuclides in water and sediment revealed elevated activity concentrations of
137
Cs in water, and measurable
134
Cs in the upper sediment layers from April 2011, possibly as a consequence of the Fukushima nuclear accident in March 2011. The potential genotoxicity of river and lake water and lake sediment was assessed under laboratory conditions using the alkaline comet assay on human peripheral blood lymphocytes, and measured levels of primary DNA damage were within acceptable boundaries. The results showed that despite the protected status of the park, anthropogenic impact exists in both its terrestrial and aquatic components. Although contaminant levels were low, further monitoring is recommended to make sure that they will not rise and cause potentially hazardous anthropogenic impacts.
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