Phosphogypsum (PG) is a waste by-product (residue) originating from the production of phosphoric acid and phosphate fertilisers. PG contains chemical and radioactive impurities, which is why it is ...mostly stockpiled in controlled areas. Worldwide, only about 15 % of PG is recycled or reused. Today, policies and business strategies prioritise sustainable development through circular economy, which certainly includes PG. This provides new opportunities for Croatia to manage its PG and make an effort to use it as an additive in different industries, such as agriculture and construction. Due to its chemical and radiological properties, PG can potentially cause problems for the environment and human health. Hence, before using PG, detailed knowledge of potential hazards is necessary to protect people and the environment. The aim of this review is to summarise available data on Croatian PG, compare them with other countries, and to identify knowledge gaps and the lack of data on potential hazardous substances in PG in order to assess the opportunities of using PG in Croatia.
The aim of this study was to investigate the natural radioactivity of Plitvice Lakes, under the assumption that due to its status as a National Park, the area can be considered an example of a ...natural freshwater system. Also, considering the transfer parameter data as the largest source of uncertainty in radiological risk assessments, the impact of site-specific data on dose rate assessment, as opposed to currently available data, was investigated. The study included gamma and alpha spectrometric measurements of
238
U,
226
Ra,
210
Pb,
228
Ra, and
40
K in water, sediment, and fish samples, as well as
137
Cs due to the coinciding of the study with the Fukushima accident. The content of naturally occurring radionuclides significantly varied in sediments of different Lakes, probably as a reflection of the different underlying geology of the area. Also, the
210
Pb distribution in sediments indicated an up to 312 Bq kg
−1
of the allochthonous contribution of this radionuclide at the beginning of the Lake’s watercourse, which probably entered into the lake system by the major inlet river with its steady decrease along downstream lakes. Low
40
K activity concentrations (27.5 ± 20.1 mBq L
−1
) in the Lake’s waters might be one of the causes of increased
137
Cs activity concentrations in fish samples (1.5 ± 0.4 Bq kg
−1
), which was found to be an order of magnitude higher than average values for different fish species from other Croatian freshwater systems (0.2 ± 0.1 Bq kg
−1
). A temporary increase of
137
Cs activity concentrations was measured in water samples collected immediately after the Fukushima accident. Calculated site-specific sediment/water distribution coefficients and fish/water concentration ratios for radium and caesium were on average lower than generic ones found in the literature. Background dose rate assessments performed by the ERICA Tool indicated a profound impact of different input data on assessment results with water activity concentrations resulting in significantly higher dose rates (0.1–67 μGy h
−1
) in comparison to sediment activity concentrations (0.03–9 μGy h
−1
). An incremental dose rate due to
137
Cs was found to be in the range of < 0.001–0.023 μGy h
−1
which, in comparison to background dose rates, can be considered negligible.
The paper analyses results of spatio-temporal radiological risk assessment
scenarios based on existing in-situ long-term monitoring data from a natural
gas processing plant to analyse the effect of ...different input data on the
assessment outcome. The ERICA Assessment Tool was used to estimate the dose
rates to biota and potential impacts due to the exposure to ionising
radiation. The input data for radiological risk assessment scenarios
included annual data on activity concentration of radionuclides in soil
from measurements performed from 1994 to 2016 and laboratory
gamma-spectrometric data related to the period from 2014 to 2019. Predicted
total dose rate to biota was generally below the ERICA Tool's screening dose
rate of 10 ?Gyh-1 or slightly above, with the highest total dose rate
estimated for lichen and bryophytes. Total dose rates to lichen and
bryophytes in the studied period show certain temporal variation, but a
specific trend was not detected. Estimated total dose rates to biota from
different assessment scenarios were below internationally proposed reference
levels for which no detrimental effects are expected. The overall potential
radiological risk to terrestrial biota from the operation of the natural gas
processing plant was found to be negligible.
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.
Accreditation in accordance with the international General Requirements for the Competence of Testing and Calibration Laboratories (HRN EN ISO/IEC 17025 standard) has become a widely accepted method ...of quality management and objective evidence of technical competence, knowledge, and skills of testing and calibration laboratories. In 2010, the Institute for Medical Research and Occupational Health (IMROH) had its management system accredited against the HRN EN ISO/IEC 17025 standard for the following scopes: determination of radioactivity, testing of ambient air quality, and testing in the scope of ionising radiation protection. This accreditation encompassed three laboratories: Radiation Protection Unit, Environmental Hygiene Unit, and the Radiation Dosimetry and Radiobiology Unit. In accordance with the rules of the Croatian Accreditation Agency, the second re-accreditation is due in 2020. This paper describes and discusses the quality management system at IMROH over the ten years of its implementation. We share our experiences about non-conformities discovered during regular work, internal audits, and external audits performed by the Croatian Accreditation Agency. The accredited management system significantly improved the performance of the accredited units, and the Institute increased its visibility and marketing advantage, consequently improving its market position.
The assessment of environmental radioactivity much relies on radionuclide content in soil. This stems from the significant contribution of soil to both external and internal exposure to ionising ...radiation via direct emission of gamma radiation and soil-to-plant radionuclide transfer, respectively. This motivated us to carry out a systematic research on the radioactivity of soil in Croatia to obtain relevant data that can be used as a basis for understanding the related effects of geomorphological, biogeographical, and climatological properties of the environment. We collected samples of the surface layer of uncultivated soil (0–10 cm) at 138 sites from all over the country and measured them for radionuclide activity concentrations by means of high-resolution gamma-ray spectrometry. This resulted in radioactivity maps containing data on activity concentrations of representative radionuclides in the environment. In this paper, which is the first in our two-part presentation, we focus on the naturally occurring
Th and
U decay chains and their correlations with the diversity of Croatian regions. For both of the chains, activity concentrations were the highest in the Dinaric region, the lowest in the Pannonian region, and intermediate in the Adriatic region. Relatively high concentrations of
Ra in the soil of the Dinaric region implied a possibility of an enhanced emanation of its progeny
Rn into the air. Activity concentrations of
Pb were additionally elevated in areas with dense vegetation, most probably due to an atmospheric deposition of airborne
Pb onto the surface of plants and their eventual decomposition on the ground.
Raša coal, mined on the Istrian Peninsula (NW Croatia) for nearly 400 years up to 1999, is notable for having superhigh organic sulfur, and high levels of selenium, uranium, vanadium, and molybdenum. ...Selenium is the poison responsible for the widespread loss of cattle and sheep. It is essential to human health in trace amounts, but higher concentrations can be harmful. An estimated 4.4.Mt. of coal remains underground within marine carbonate rocks. The study area belongs to the coastal karst of the Adriatic Sea. Several abandoned coal-mine discharges (CMDs) were released into local streams and the Raša Bay for decades. Therefore, the water quality of a natural karst spring (Fonte Gaja), the Raša Bay seawater, municipal wastewater, and the Raša CMDs were investigated, focusing on sulfur, selected metal(loid)s (major, minor, and trace), radioactivity, and cytotoxicity. The Fonte Gaja spring water, unrelated to the Raša CMD, served as a reference. Its values of Se, U, V, and Mo (µg/L) were as follows: 1.09, 0.75, 1.37, and 2.04, respectively. However, the respective levels (µg/L) were increased in the rest of the water samples as follows: 10.9, 10.8, 4.60, and 33.1. Water sulfate levels were low though. Total beta activities of the CMDs and Raša Bay water were 235 and 1320 Bq/m3, respectively, below the guideline level of 2000 Bq/m3. The cytotoxicity of water samples on the RTG-2 fish cells was not statistically significant. The large volumes of water involved mean the transport of rather large amounts of Se and U, and their deposition in the Adriatic Sea. Due to the complexity of the karst hydrogeology, knowledge of Se and U circulation patterns is highly needed.
We took samples of uncultivated soil from the surface layer (0–10 cm) at 138 sites from all over Croatia and measured their radionuclide activity concentrations with high-resolution gamma-ray ...spectrometry. This second part of our report brings the results on
K and
Cs to complement those on the
Th and
U decay chains addressed in the first part. Together they give the most complete picture of radioactivity of Croatian soil so far. Activity concentrations of
K were the highest in the Pannonian region, and there was an opposite trend for
Cs. We found that the concentrations of
Cs tended to increase with altitude, annual precipitation, and vegetation density. The concentration ratio of
Cs and K in soil, which indicates the potential for
Cs entering food chains via uptake by plants, was the lowest in agriculturally important areas in the east of the Pannonian region. In addition, we used the obtained results on activity concentrations to calculate the related absorbed dose rate as a measure of external exposure to ionising radiation from soil. The sum of the absorbed dose rates for naturally occurring radionuclides and
Cs showed that external exposure was generally the highest in the Dinaric region and Istrian Peninsula.
The contents of natural radionuclides (radium, uranium and potassium) were measured in the area of a phosphate fertilizer factory in central Croatia, as a part of extended and still ongoing ...monitoring program of radioactive contamination of human environment in Croatia that is performed by the Radiation Protection Unit of the Institute for Medical Research and Occupational Health in Zagreb. Activity concentrations in all analysed media (waste water, trickling water from piezometers, phosphogypsum deposit and final products) considerably fluctuated, especially in phosphogypsum and waste water. Mean
226Ra activity concentration in waste phosphogypsum was measured to be 483
±
190
Bq
kg
−1. Based on that value, it was estimated that 4
million
m
3 of phosphogypsum that have been deposited up to now contain about 4.3
×
10
12
Bq, i.e. about 200
g of
226Ra. However, effective dose for an adult that would be incurred by consumption of water from nearby wells was estimated to be 5.3
±
1.3
μSv. The results show that
226Ra activities cause effective doses, which are below the recommended maximum as the estimated annual
226Ra effective dose does not exceed 0.1
mSv as recommended by the World Health Organization.
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