Maarit Muikku

The mean concentration of uranium in drinking water, urine, and hair of the occupationally unexposed Finnish working population.

Uranium concentrations in the household water, urine, and hair of the occupationally unexposed Finnish working population were determined using inductively coupled plasma mass spectrometry (ICP-MS). The age of the randomly selected participants ranged from 18 to 66 y. The mean concentrations of uranium in water, urine, and hair were 1.25 &mgr;g L−1, 0.016 &mgr;g L−1, and 0.216 &mgr;g g−1, respectively. The mean uranium concentration in hair of the Finnish working population was from 3- to 15-fold higher than the values reported in the literature, while the mean uranium concentration in urine was similar to those measured elsewhere in Europe. The observed large variation in the uranium concentrations in hair and urine can be explained by the variation in the uranium concentration in drinking water. Exceptionally high concentrations have been measured in private drilled wells in the granite areas of Southern Finland.

Effective half-lives of 134Cs and 137Cs in reindeer meat and in reindeer herders in Finland after the Chernobyl accident and the ensuing effective radiation doses to humans.

Monitoring of 137Cs in reindeer herders and in reindeer meat in Finnish Lapland began in the early 1960s and has continued until today. The monitoring of 137Cs in reindeer herders and in reindeer meat in the Halla area began after the Chernobyl accident. In this study, reindeer herders together with reindeer meat samples were monitored for gamma-emitting radionuclides from two separate areas in the Finnish reindeer management area, Northern Finland and the Halla area. The effective half-lives determined for 137Cs in reindeer meat were from 3.0 ± 1.7 to 5.1 ± 0.5 y. For 134Cs, the observed effective half-lives in reindeer meat were from 1.3 ± 0.2 to 1.5 ± 0.1 y. The effective half-lives among male and female reindeer herders in Northern Finland were 5.5 ± 1.3 and 4.4 ± 0.9 y, respectively, for the body-burden of 137Cs. In the Halla reindeer herding cooperative, located to the south of Finnish Lapland in the province of Kuusamo, the effective half-lives in the reindeer herders were shorter, about 1–2 y. The 134Cs × 137Cs−1 ratios decreased more rapidly in reindeer meat and also in humans in the Halla area than in Northern Finland. This implies faster removal of Chernobyl-derived cesium from the reindeer-man food chain in the Halla area. The contribution of Chernobyl fallout (percent) in reindeer meat was 70% and 80% in the Paistunturi and Ivalo cooperatives, respectively, and 50% and 80% in the western and eastern part of Halla cooperative, respectively. In humans, the contribution of Chernobyl fallout to 137Cs in whole-body content was 60% in Northern Finland and 80% in the Halla area. The mean committed effective doses of 137Cs for reindeer herders in Finnish Lapland decreased from 0.36 mSv y−1 in 1987 to 0.053 mSv y−1 in 2005.

Exogenous contamination of uranium in human scalp hair

AbstractThe use of human scalp hair as a bioindicator of occupational or environmental exposure has been the subject of some debate over the years. One problem is how to distinguish internal contamination from external contamination. In this study, possibility that elevated levels of natural uranium in human hair are partly due to the exogenously bound uranium from uranium-rich household water was tested. Hair samples from six adult volunteers were cut and then exposed externally to uranium by using washing water with highly elevated levels of natural uranium. After that, and before making the analysis using inductively coupled plasma mass spectrometry (ICP-MS), the samples were washed using two commonly used washing procedures in order to remove external contamination. No quantitative information was gained in the tests, but it was shown that the use of uranium-rich water when washing hair affects the uranium concentration in hair. Although the samples were cleaned according to widely used washing procedures before the analysis, the uranium concentrations in hair were about three orders of magnitude higher after the tests. The possibility of external contamination should be kept in mind, especially when considering hair as an excretion pathway for estimating internal dose.

Natural variation in 210Po and 210Pb activity concentrations in the urine of Finnish population groups

A study to determine activity concentrations of 210Pb and 210Po in the urine of certain Finnish population groups was conducted, to investigate the variation in natural background level of urinary excretion. The study participants were divided into three groups mainly based on their diet. The first group comprised recreational fishermen and the second group represented people consuming more reindeer meat than an average Finn, while people using drinking water with very high activity concentrations of 210Po were selected for the third group. The fourth group was a control group. The mean urinary excretion of 210Po in groups 1 and 2 was 73 and 100xa0mBqxa0d−1, respectively. These values were higher than the value of the control group (20xa0mBqxa0d−1) and the mean values reported in the literature. The mean daily urinary excretion of 210Pb in groups 1 and 2, 70 and 52xa0mBqxa0d−1, was also slightly higher than that in the control group (32xa0mBqxa0d−1). In contrast, the excretion rates of both 210Po and 210Pb for the members of group 3 were one to two orders of magnitude higher than those reported in the literature. This was clearly due to the elevated levels of natural radionuclides in their drinking water. The present study demonstrates the importance of possessing good knowledge of the background levels, in order to allow the determination of the additional exposure due, for example, to the malevolent use of radiation.

COMET strongly supported the development and implementation of medium-term topical research roadmaps consistent with the ALLIANCE Strategic Research Agenda

The ALLIANCE6 Strategic Research Agenda (SRA) initiated by the STAR7 Network of Excellence and integrated in the research strategy implemented by the COMET consortium, defines a long-term vision of the needs for, and implementation of, research in radioecology. This reference document, reflecting views from many stakeholders groups and researchers, serves as an input to those responsible for defining EU research call topics through the ALLIANCE SRA statement delivered each year to the EJP-CONCERT8 (2015-2020). This statement highlights a focused number of priorities for funding. Research in radioecology and related sciences is justified by various drivers, such as policy changes, scientific advances and knowledge gaps, radiological risk perception by the public, and a growing awareness of interconnections between human and ecosystem health. The SRA is being complemented by topical roadmaps that have been initiated by the COMET9 EC-funded project, with the help and endorsement of the ALLIANCE. The strategy underlying roadmap development is driven by the need for improved mechanistic understanding across radioecology. By meeting this need, we can provide fit-for-purpose human and environmental impact/risk assessments in support of the protection of man and the environment in interaction with society and for the three exposure situations defined by the ICRP (i.e., planned, existing and emergency). Within the framework of the EJP-CONCERT the development of a joint roadmap is under discussion among all the European research platforms and will highlight the major research needs for the whole radiation protection field and how these are likely to be addressed by 2030.

Occupational exposure to 131I – A case study

AbstractIn a laboratory in a company manufacturing radiopharmaceuticals, a laboratory technician was contaminated with 131I. The employee was preparing 131I capsules for thyroid carcinoma treatment. The employee was wearing two pairs of protective gloves and, when changing gloves, noticed a rupture in the right inner glove but no visible rupture in the outer glove. Only 3-4 h later, routine monitoring revealed heavy contamination of the back of the right hand. Immediate actions to decontaminate the hand were taken on-site. Stable iodine was not administered. On the next day, besides persisting heavy contamination of the hand, 131I was also detected in the thyroid gland. Based on original measurements on-site and later follow-up at STUK, including surface contamination measurements and whole body counting, the original 131I activity on the hand was estimated at 12 MBq and the superficial skin dose at 33 Gy, affecting a skin area of about 10 cm2. The thyroid dose was estimated at 430 mGy. Eleven days after the incident, the skin was dry and slightly desquamated. After 15 d, the skin was intact with no desquamation left. No further signs of skin damage have occurred. Cytogenetic analysis of circulating lymphocytes indicated a slight elevation of chromosomal aberrations.

Natural radionuclides in human hair

Naturally occurring radionuclides of terrestrial origin, such as 238U, 235U, 226Ra, 210Po and 210Pb, are present to various degrees in all environmental media, including the human body. Like other pollutants, many natural radioactive substances also accumulate in hair. In this article, the transfer to human scalp hair and typical concentrations in hair are presented for some natural radionuclides. Uranium is a primordial radioactive element ubiquitously present in the Earth’s crust. Natural uranium consists of a mixture of three radioactive isotopes: 238U (99.2745% by mass), 235U (0.7200%) and 234U (0.0054%). All three isotopes are α-emitters with very long half-lives. In addition to uranium isotopes, 226Ra, 210Po and 210Pb are taken into account. They occur widely in the natural environment as they are part of the 238U decay chains. All these radionuclides are transferred from the environment to the human body via inhalation and the ingestion of foodstuffs and water. The intake of natural radionuclides varies depending on the diet and residential location. Consequently, the concentrations in human hair vary greatly. The concentrations of uranium, 210Pb and 210Po in human hair have been observed to vary between <0.5-140,000 ng/g, 0.7-10 mBq/g and 0.4-59.3 mBq/g, respectively. Natural variation in the transfer of natural radionuclides into hair complicates the use of hair as an accurate bioindicator.