In South Greenland, public concerns have linked "black livers" in sheep to presumed environmental pollution from the Kvanefjeld mining exploration project. Elevated concentrations of metals and radionuclides in the area reflect natural geochemistry and weathering processes, not pollution from exploration activities. However, in response, we conducted a preliminary case-control study to diagnose the condition, investigate links between liver discoloration and environmental concentrations of metals and radionuclides, and to estimate the annual effective dose to the public from polonium-210 (210Po) ingestion via sheep and lamb liver consumption. We also evaluated the prevalence of acquired melanosis, grazing and herd effects, and their association with carcass quality and disease markers. Histological analysis confirmed acquired melanosis in affected liver samples. No statistically significant differences in concentrations of chemical elements or radionuclides (including ²¹⁰Po and ²¹⁰Pb) were found between case and control groups, across age groups, grazing areas, or farms. Except for the most exposed children (10% percentile), the estimated annual effective dose to adults and children from 210Po ingestion in black and healthy livers remained below the world average of 120 µSv due to the ingestion of naturally occurring radionuclides. The overall prevalence of ovine acquired melanosis based on a large sample size was 10.59%, with herd prevalence ranging from 0% to 51.79%. Age-specific prevalence was 10.38% in lambs and 13.40% in adult sheep. Acquired melanosis was negatively correlated with fat and muscle content in carcasses. Acquired melanosis in sheep from South Greenland does not pose a health risk to humans through liver consumption.

Radon-222 (222Rn) and its decay products are the primary sources of a population’s exposure to background ionizing radiation. Radon decay products are the leading cause of lung cancer for non-smokers and the second leading cause of lung cancer after smoking for smokers. A community-driven long-term radon survey was completed in 232 residential homes in different subdivisions of Whitehorse, the capital of the Yukon, during the heating season from November to April in 2016–2017 and in 2017–2018. Radon concentrations were measured in living rooms and bedrooms on ground floors. The arithmetic and geometric means of indoor radon activity concentrations in different subdivisions of Whitehorse ranged from 52 ± 0.6 Bq m−3 and 37 ± 2.3 Bq m−3 in the Downtown area of Whitehorse to 993.0 ± 55.0 Bq m−3 and 726.2 ± 2.4 Bq m−3 in Wolf Creek. Underlying geology and glacial surfaces may partly explain these variations of indoor radon concentrations in subdivisions of Whitehorse. A total of 78 homes (34.0%) had radon concentrations higher than 100 Bq m−3, 47 homes (20.5%) had concentrations higher than 200 Bq m−3 and 33 homes (14.4%) had concentrations higher than 300 Bq m−3. The indoor radon contribution to the annual effective inhalation dose to residents ranged from 3.0 mSv in the Downtown area to 51.0 mSv in Wolf Creek. The estimated annual average dose to adults in Whitehorse, Yukon, is higher than the world’s average annual effective dose of 1.3 mSv due to the inhalation of indoor radon. The annual radon inhalation effective dose was assessed using radon measurements taken during winter; hence the assessed dose may be overestimated. Cost-efficient mitigation methods are available to reduce radon in existing buildings and to prevent radon entry into new buildings.

Indoor radon and its decay products are the primary sources of the population's exposure to background ionizing radiation. Radon decay products are one of the leading causes of lung cancer, with a higher lung cancer risk for smokers due to the synergistic effects of radon decay products and cigarette smoking. A total of 459 year-long radon measurements in 257 detached and semi-detached residential homes in southwest and south Greenland were carried out, and a dose assessment for adults was performed. The annual arithmetic and geometric means of indoor radon concentrations was 10.5 +/- 0.2 Bq m- 3 and 8.0 +/- 2.3 Bq m- 3 in Nuuk, 139.0 +/- 1.0 Bq m- 3 and 97.3 +/- 2.1 Bq m- 3 in Narsaq, and 42.1 +/- 0.7 Bq m- 3 and 22.0 +/- 3.1 Bq m- 3 in Qaqortoq. Arithmetic and geometric mean radon concentration of 79.0 Bq m- 3 and 50.3 Bq m- 3 were estimated for adult, person-weighted living in south Greenland. The total number of detached and semi-detached residential homes where indoor radon is exceeding 100 Bq m- 3, 200 Bq m- 3, and 300 Bq m- 3 is 37 homes (15.0%), 13 homes (5.2%), and 8 homes (3.2%), respectively. A positive correlation between indoor air radon concentrations and underlying geology was observed.The indoor radon contribution to the annual inhalation effective dose to an average adult was 0.5 mSv in Nuuk, 6.5 mSv in Narsaq, 2.0 mSv in Qaqortoq, and 4.0 mSv for south Greenland adult person weighted. The estimated annual average effective dose to adults in Narsaq is higher than the world's average annual effective dose of 1.3 mSv due to inhalation of indoor radon. Cost-efficient mitigation methods exist to reduce radon in existing buildings, and to prevent radon entry into new buildings.

Polonium-210 (210Po) is a radionuclide sentinel as it bioaccumulates in marine organisms, thereby being the main contributor to committed dietary doses in seafood consumers. Although seafood and marine mammals are an important part of the traditional Inuit diet, there is a general lack of information on the 210Po concentrations in the Greenlandic marine food chain leading to the human consumer. Here, we determine background 210Po concentrations in edible parts of different marine organisms from Greenland and provide a dose assessment. Blue mussels (Mytilus edulis), organs of ringed seal (Pusa hispida) and polar bear (Ursus maritimus) displayed significantly elevated 210Po concentrations in respect to all other studied organisms (p < 0.001). 210Po concentrations ranged from 0.02 Bq kg-1, w.w. in Greenland halibut (Reinhardtius hippoglossoides) muscle to 78 Bq kg-1, w.w. and 202 Bq kg-1, w.w. in ringed seal muscle and kidneys, respectively. 210Po concentration ratio for edible parts increases in the order bladderwrack (Fucus Vesiculosus), northern shrimp (Pandalus borealis), blue mussels, and from fish species to ringed seal and polar bear. 210Po distribution in fish, ringed seal, and polar bear follows a general pattern, the lowest concentrations were in muscle, and the highest concentrations were in the organs involved in metabolism. The derived 210Po annual absorbed dose in edible parts of studied marine organisms are several orders of magnitude lower than the recommended dose rate screening value of 10 μGy h-1. Effective doses from intake of 210Po to Greenland average children (1.4 mSv y-1), and high seafood and marine mammal consumers (2 mSv y-1 for adults and 3.6 mSv y-1 for children) are higher than the world average annual effective dose due to ingestion of naturally occurring radionuclides.

Naturally occurring radionuclides, in particular, polonium-210 (Po-210), have a greater contribution than anthropogenic radionuclides to the annual effective dose received by the general public due to consumption of seafood. Knowledge of potential trophic sources and transfer of Po-210 to seabird species and subsequently to the Greenlandic people is, however, still poor. Here, we assess the transfer of Po-210 and Pb-210 to seabirds sampled during autumn and winter 2017 and 2018 in Greenland and provide a dose assessment. The activity concentrations of Po-210 in muscle and liver, respectively, ranged from 0.2 +/- 0.1 Bq kg(-1) w.w. in glaucous gull (Larus hyperboreus) to 212 +/- 22.6 Bq kg(-1) w.w. in thick-billed murre (Uric loinvia) and from 32.0 9.4 Bq kg(-1) w.w. in common eider (Somateria mollissima) to 40.5 +/- 49.0 Bq kg(-1) w.w. in thick-billed murre. (210)po was non-uniformly distributed in the body of thick-billed murre. Kidneys and feathers showed higher Po-210 activity concentrations than heart and bone. The Po-210/Pb-210 activity concentration ratios are higher than unity, indicating that Po-210 is preferentially taken up by seabirds compared to its progenitor Pb-210. The derived annual absorbed dose from Po-210 to the whole body of thick-billed murre was 6.4 x 10(2) +/- 3.0 x 10(2) mu Gy. The annual effective dose to the average adult and representative person in Greenland due to ingestion of 210Po in seabirds was estimated to 13.0 mu Sv and 57.0 mu Sv, respectively. This derived dose is low and poses a slight risk, and risk communication is therefore deemed unnecessary. (C) 2020 Elsevier B.V. All rights reserved.

The environmental mobility and bioavailability of radionuclides are related to their physicochemical forms, namely species. We here present a speciation analysis of important radionuclides including 129I (also 127I), 137Cs, 232Th, 238U and plutonium isotopes (239Pu and 240Pu) in soil (IAEA-375) and sediment (NIST-4354) standard reference materials and two fresh sediment samples from Øvre Heimdalsvatnet Lake, Norway. A modified sequential extraction protocol was used for the speciation analysis of these samples to obtain fractionation information of target radionuclides. Analytical results reveal that the partitioning behaviour, and thus the potential mobility and bioavailability, are exclusively featured for the individual radionuclide. Iodine is relatively mobile and readily binds to organic matter, while plutonium is mainly bound to both organic matter and nitric acid leachable fractions. Thorium is predominated in nitric acid leachable fraction and caesium is primarily observed in nitric acid and aqua regia leachable fractions and residue. Our analytical results reveal that around 50% of uranium might still remain in the residue which could not be extracted with aggressive acid, namely, aqua regia.

Natural organic matter, such as humic and fulvic acids and humin, plays a key role in determining the fate and mobility of radioiodine in soil and sediments. The radioisotope I-129 is continuously produced and released from nuclear fuel reprocessing plants, and as a biophilic element, its environmental mobility is strongly linked to organic matter.Due to its long half-life (15.7 million years), I-129 builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different types of organic matter in soil and sediment is rarely explored. Here we present a sequential extraction of I-129 and I-127 chemical forms encountered in a Danish soil, a soil reference material (IAEA-375), an anoxic marine sediment from Southern Norway and an oxic sediment from the Barents Sea. The different forms of iodine are related to water soluble, exchangeable, carbonates, oxides as well as iodine bound to humic acid, fulvic acid and to humin and minerals. This is the first study to identify I-129 in humic and fulvic acid and humin. The results show that 30-56% of the total I-127 and 42-60% of the total I-129 are associated with organic matter in soil and sediment samples. At a soil/sediment pH below 5.0-5.5, I-127 and I-129 in the organic fraction associate primarily with the humic acid while at soil/sediment pH > 6 I-129 was mostly found to be bound to fulvic acid. Anoxic conditions seem to increase the mobility and availability of iodine compared to oxic, while subaerial conditions (soils) reduces the availability of water soluble fraction compared to subaqueous (marine) conditions. (C) 2011 Elsevier Ltd. All rights reserved.

Despite the common incorporation of iodine in the biological cycle and occurrence of huge contamination of the radioactive isotope 129I in the Baltic Proper, Skagerrak and Kattegat, there is no data on chemical speciation of iodine in these waters. We here present first time data on iodine isotopes 129I and 127I species as iodide and iodate in surface seawater samples collected from 16 locations in August 2006 and 19 locations in April 2007 in the Baltic Proper, Skagerrak and Kattegat. After extensive separation methods, the isotopes concentrations were determined using accelerator mass spectrometry (AMS) technique for the 129I and inductively coupled plasma mass spectroscopy (ICP-MS) for 127I. High concentrations of both isotopes species were found in the Skagerrak–Kattegat basins, whereas the values in the Baltic Proper are low for both species. The ratios of 129I−/129IO3− and 127I−/127IO3− significantly increase from south to central Baltic Sea, and iodide (both isotopes) appears as the predominant inorganic iodine species along the Baltic Sea. The results show insignificant change in 129I and 127I speciation and suggest that reduction of iodate and oxidation of iodide in Skagerrak and Kattegat may be a slow process. Additionally, the positive correlation between salinity and iodide and iodate (both isotopes) may reflect effective control of Skagerrak water mass on iodine distribution in surface water of the Baltic Sea.

As a long-lived beta-emitting radioisotope of iodine, 129I is produced both naturally and as a result of human nuclear activities. At present time, the main part of 129I in the environment originates from the human nuclear activity, especially the releases from the spent nuclear fuel reprocessing plants, the 129I/127I ratios have being reached to values of 10−10 to 10−4 in the environment from 10−12 in the pre-nuclear era. In this article, we review the occurrence, sources, inventory, and concentration level of 129I in environment and the method for speciation analysis of 129I in the environment. Measurement techniques for the determination of 129I are presented and compared. An overview of applications of 129I speciation in various scientific disciplines such as radiation protection, waste depository, and environmental sciences is given. In addition, the bioavailability and radiation toxicity (dose to thyroid) of 129I are discussed.