A simple model to estimate deposition based on a statistical reassessment of global fallout data

Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. Monitoring of the resulting global fallout was carried out globally by the Environmental Measurements Laboratory and the UK Atomic Energy Research Establishment as well as at national level by some countries. A correlation was identified between fallout deposition and precipitation and an uneven distribution with latitude. In this study, the available data from 1954 to 1976 for (90)Sr and (137)Cs were reanalysed using analysis of covariance (ANCOVA) and logarithmically transformed values of the monthly deposition density as the response variable. Generalized additive models (GAM) were used to explore the relationship of different variables to the response variable and quantify the explanatory power that could be achieved. The explanatory variables which consistently explained most of the variability were precipitation at each site, latitude and change with time and a simple linear model was produced with similar explanatory power as the GAM. The estimates improved as the temporal resolution of the precipitation data increased. A good log-log fit could be obtained if a bias of about 1-6 mm precipitation per month was added, this could be interpreted as dry deposition which is not otherwise accounted for in the model. The deposition rate could then be explained as a simple non-linear power function of the precipitation rate (r(0.2-0.6) depending on latitude band). A similar non-linear power function relationship has been the outcome of some studies linking wash-out and rain-out coefficients with rain intensity. Our results showed that the precipitation rate was an important parameter, not just the total amount. The simple model presented here allows the recreation of the deposition history at a site, allowing comparison with time series of activity concentrations for different environmental compartments, which is important for model validation.

Tracking of airborne radionuclides from the damaged Fukushima Dai-ichi nuclear reactors by European networks

Radioactive emissions into the atmosphere from the damaged reactors of the Fukushima Dai-ichi nuclear power plant (NPP) started on March 12th, 2011. Among the various radionuclides released, iodine-131 ((131)I) and cesium isotopes ((137)Cs and (134)Cs) were transported across the Pacific toward the North American continent and reached Europe despite dispersion and washout along the route of the contaminated air masses. In Europe, the first signs of the releases were detected 7 days later while the first peak of activity level was observed between March 28th and March 30th. Time variations over a 20-day period and spatial variations across more than 150 sampling locations in Europe made it possible to characterize the contaminated air masses. After the Chernobyl accident, only a few measurements of the gaseous (131)I fraction were conducted compared to the number of measurements for the particulate fraction. Several studies had already pointed out the importance of the gaseous (131)I and the large underestimation of the total (131)I airborne activity level, and subsequent calculations of inhalation dose, if neglected. The measurements made across Europe following the releases from the Fukushima NPP reactors have provided a significant amount of new data on the ratio of the gaseous (131)I fraction to total (131)I, both on a spatial scale and its temporal variation. It can be pointed out that during the Fukushima event, the (134)Cs to (137)Cs ratio proved to be different from that observed after the Chernobyl accident. The data set provided in this paper is the most comprehensive survey of the main relevant airborne radionuclides from the Fukushima reactors, measured across Europe. A rough estimate of the total (131)I inventory that has passed over Europe during this period was <1% of the released amount. According to the measurements, airborne activity levels remain of no concern for public health in Europe.

Assessing deposition levels of 55Fe, 60Co and 63Ni in the Ignalina NPP environment

Two RBMK-1500 reactor units operated in Lithuania in the 1987-2004 period (one of them was stopped for decommissioning in 2004). This study presents a preliminary investigation of surface deposition density levels of (55)Fe and (63)Ni in moss samples collected in the close vicinity of the Ignalina NPP. Non-destructive analysis by the HPGe gamma-spectrometry was followed by radiochemical separation. Radiochemical analysis was based on anion-exchange and extraction chromatography. (55)Fe and (63)Ni activities were measured by liquid scintillation counting (LSC). The results indicate that the deposition values of (55)Fe are generally higher than those of (60)Co and (63)Ni.

Requirements for estimation of doses from contaminants dispersed by a 'dirty bomb' explosion in an urban area

The ARGOS decision support system is currently being extended to enable estimation of the consequences of terror attacks involving chemical, biological, nuclear and radiological substances. This paper presents elements of the framework that will be applied in ARGOS to calculate the dose contributions from contaminants dispersed in the atmosphere after a 'dirty bomb' explosion. Conceptual methodologies are presented which describe the various dose components on the basis of knowledge of time-integrated contaminant air concentrations. Also the aerosolisation and atmospheric dispersion in a city of different types of conceivable contaminants from a 'dirty bomb' are discussed.

Root uptake of lead by Norway spruce grown on 210Pb spiked soils

The root uptake of lead (Pb) by trees and the transfer of Pb by leaf litter deposition to the forest floor were investigated through a pot experiment with Norway spruce. Natural Pb and radio isotopic lead (210Pb) were determined in needles and twigs and in the pot soil spiked with 210Pb. Calculations of the specific activity in plant material and in the supporting pot soil showed that less than 2% of the Pb content of needles and twigs originates from root uptake and approximately 98% are deposited from the atmosphere. Atmospheric Pb has declined by a factor of 7 from 1980 to 2007 but is still a major pathway of Pb to vegetation and topsoils. The conclusion from the experiment is that the internal circulation of Pb through root uptake, translocation and litterfall, gives an insignificant input of Pb to the forest floor compared to atmospheric deposition.

Estimation of health hazards resulting from a radiological terrorist attack in a city

In recent years, the concern for protection of urban populations against terror attacks involving radiological, biological or chemical substances has attracted increasing attention. It sets new demands to decision support and consequence assessment tools, where the focus has traditionally been on accidental exposure. The aim of the present study was to illustrate issues that need to be considered in evaluating the radiological consequences of a 'dirty bomb' explosion. This is done through a worked example of simplified calculations of relative dose contributions for a specific 'dirty bomb' scenario leading to atmospheric dispersion of 90Sr contamination over a city area. Also, the requirements of atmospheric dispersion models for such scenarios are discussed.

New developments to support decision-making in contaminated inhabited areas following incidents involving a release of radioactivity to the environment

The Chernobyl accident demonstrated that releases from nuclear installations can lead to significant contamination of large inhabited areas. A new generic European decision support handbook has been produced on the basis of lessons learned on the management of contaminated inhabited areas. The handbook comprises detailed descriptions of 59 countermeasures in a standardised datasheet format, which facilitates a comparison of features. It also contains guidance in the form of decision flowcharts, tables, check lists and text to support identification of optimised solutions for managing the recovery of inhabited areas within a framework consistent with ICRP recommendations. A new comprehensive inhabited-area dose model is also being developed for implementation in the ARGOS and RODOS decision support systems. Shortcomings of previous models are demonstrated. Decision support modelling in relation to malicious dispersion of radioactive matter in inhabited areas is also discussed. Here, the implications of, e.g., particle sizes and dispersion altitude are highlighted.

Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea)

A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units.

Performance of four clinical screening tools to select peri- and early postmenopausal women for dual X-ray absorptiometry

Several methods to select postmenopausal women for dual X-ray absorptiometry (DXA) have been proposed. We decided to compare the performance of three clinical decision rules (SCORE, ORAI, OST) with the usual case-finding strategy based on the presence of a major risk factor for future fracture (CFMRF). The study subjects were 2009 healthy, white, peri- or early postmenopausal women participating in the Danish Osteoporosis Prevention Study (DOPS). DXA results expressed as T-scores and scores on SCORE, ORAI, OST and CFMRF were extracted from the DOPS database. First, we evaluated the screening tools as originally described by the developers. The resulting sensitivities and specificities ranged from 18% to 92% and from 66% to 85%, respectively. Only OST achieved a high sensitivity (92%) with respect to femoral neck T-score < or = -2.5; however, the sensitivity with respect to lumbar spine T-score < or = -2.5 was only 51%. Next, the performance of the screening tools was evaluated against T-score < or = -2.0 (and T-score < or = -2.5) in at least one of the regions: femoral neck, total hip or lumbar spine. Using ROC curve analysis, we determined cut-offs yielding sensitivities as close as possible to 90%. The CFMRF and the ORAI tool were too coarse to yield 90% sensitivity. The performances of OST and SCORE were equal from a clinical perspective in that the sensitivities and the specificities varied from 89% to 94% and from 23% to 28%, respectively. The performance of CFMRF was no better than could be expected by chance, yielding a sensitivity of 19% and a specificity of 85%. Applying SCORE or OST 75% of the women would have to be referred for densitometry to identify 90% of the women with T-score < or = -2.0 (or T-score < or = -2.5) in at least one region. In conclusion, our results question the utility of all the evaluated tools for screening peri- and early postmenopausal women for low BMD. However, if a decision on referral has to be made, it may be based on the simple OST rule, which performed as well as or better than any of the other tools.

Environmental radioactivity in the South Urals 1990-1997. An international study supported by INTAS, EC and national funding

Radioecological studies carried out in a joint co-operation between Russian, Ukrainian and Danish Laboratories are reported. The environmental impact of routine, discharges as well as accidental events, notably the Kyshtym accident in 1957 and the Karachay wind dispersion in 1968 have been studied. From measurements and based on model assumptions it has been estimated that the Ob river system outside Mayak, i.e. first of all the Techa and Iset rivers and their floodplains contain 0.1 PBq 90Sr, 0.3 PBq 137Cs and 0.8 TBq 239, 240Pu. The uncertainty of these estimates is a factor of 3-4. The present contamination from the Kyshtym accident outside the Mayak area is calculated to 0.1-0.5 PBq 90Sr and from the Karachay incident the contamination is 0.05-0.1 Bq 137Cs. The environmental contaminations with Pu from these two events are in the order of 1 TBq. The occurrence of 99Tc, 129I and 237Np in highly contaminated Techa river sediments collected outside Mayak is for the first time reported.

Iodine-129 and caesium-137 in Chernobyl contaminated soil and their chemical fractionation

Soil samples from areas in Belarus, Russia and Sweden contaminated by the Chernobyl accident were analysed for (129)I by radiochemical neutron activation analysis, as well as for 137Cs by gamma-spectrometry. The atomic ratio of (129)I/137Cs in the upper layer of the examined soil cores ranged from 0.10 to 0.30, with an average of 0.18, and no correlation between (129)I/137Cs ratio and the distance from Chernobyl reactor to sampling location was observed. It seems feasible to use the (129)I/137Cs ratio to reconstruct the deposition pattern of 131I in these areas. The association of (129)I and 137Cs in the Chernobyl soil and Irish Sea sediment was investigated by a sequential extraction method. Similar speciation of (129)I in the Chernobyl soil and Irish Sea sediment was found. Approximately 70% of (129)I is bound to oxides and organic matter, and 10-20% is in the readily available phase, while most of the 137Cs (73%) in Chernobyl soil remains in the extraction residue.

Iodine-129 in thyroid and urine in Ukraine and Denmark

Human thyroids collected from Gomel in Belarus, sheep thyroid from Jutland and human urine from Zealand in Denmark were analysed for 129I and 127I concentrations. The ratios of 129I/127I in human thyroid in Gomel are 2.65-11.0 x 10(-9) with an average of 7.21 x 10(-9), which is one order of magnitude higher than those from Asia and South America (10(-10)), but significantly lower than those observed in west Europe (10(-8)). A weak negative correlation (P < 0.05) between 129I/127I ratio in human thyroid and the age of the subjects was observed in Gomel. The average ratio of 129I/127I in sheep thyroids from Jutland of Denmark is 1.81 x 10(-7), which is two orders of magnitude higher than those in south hemisphere, and Asia. It is also significantly higher than those observed in other west European countries before 1984 and that in human thyroid in Gomel. The high thyroid 129I level in Jutland is attributed to the release of reprocessing plants in France and UK. The 129I/127I ratios in human urine in Zealand of Denmark are 0.86-2.86 x 10(-8). The possibility of using urine 129I to evaluate the thyroid exposure to 129I is investigated.

Level and origin of iodine-129 in the Baltic Sea

Environmental samples, such as seawater, seaweed, lake water, lake sediment and grass collected from the Baltic Sea area were analyzed for 129I and 127I by radiochemical neutron activation analysis. In 2000, the concentration of 129I in the seawater from Borholm and Møen in the Baltic Sea has reached 6.0 x 10(-13) and 16 x 10(-13) g/l, respectively, these are more than two orders of magnitude higher than the global fallout level. The highest value of 270 x 10(-13) g/l being found in the seawater from the Kattegat. By comparison of the level of 129I in the lake water and precipitation in this region, it is estimated that more than 95% of 129I in the Baltic Sea originates from reprocessing emissions, especially from the French nuclear fuel reprocessing plant at La Hague. More than 30% of 129I in the south Baltic and 93% in the Kattegat directly originates from the marine discharges of the European reprocessing plants.

[Hormone replacement therapy reduces the risk of forearm fracture in postmenopausal women. Results of the Danish Osteoporosis Prevention Study]

In a prospective, controlled, comprehensive cohort trial of 2,016 healthy early postmenopausal women aged 45-58 years we studied fracture prevention through the use of oestrogen. There were two main study arms: a randomised arm (randomised to HRT [n = 502] or not [n = 504]) and a non-randomised arm (on HRT [n = 221] or not [n = 789] by own choice). After five years, an intention-to-treat analysis (n = 2,016) showed a reduction in the overall fracture risk (RR = 0.73, 95% CI: 0.50-1.05) and in the forearm fracture risk (RR = 0.45, 95% CI: 0.22-0.90) with oestrogen. Restriction of the analysis to women who had adhered to their initial allocation of either oestrogen (n = 395) or no oestrogen (n = 977) showed a significant reduction in both the overall fracture risk (RR = 0.61, 95% CI: 0.39-0.97) and the risk of forearm fractures (RR = 0.24, 95% CI: 0.09-0.69). We conclude that it is possible to reduce the number of forearm fractures in early postmenopausal women by the use of oestrogen as primary prevention.

Discordance between changes in bone mineral density measured at different skeletal sites in perimenopausal women--implications for assessment of bone loss and response to therapy: The Danish Osteoporosis Prevention Study

Assessing bone loss and gain is important in clinical decision-making, both in evaluating treatment and in following untreated patients. The aim of this study was to correlate changes in bone mineral density (BMD) at different skeletal sites during the first 5 years after menopause and determine if forearm measurements can substitute for dual-energy X-ray absorptiometry (DXA) of the spine and hip. BMD was measured at 0, 1, 2, 3, and 5 years using Hologic 1000/W and 2000 densitometers in 2,016 perimenopausal women participating in a national cohort study. This analysis comprises 1,422 women remaining in the study after 5 years without changes to their initial treatment (hormone-replacement therapy [HRT], n = 497, or none, n = 925). Despite correlated rates of change between forearm and spine (r2 = 0.11; p < 0.01), one-half of those who experienced a significant decrease in spine BMD at 5 years showed no significant fall in forearm BMD (sensitivity, 50%; specificity, 85%; kappa = 0.25). The total hip had significant better agreement with spine (sensitivity, 63%; specificity, 85%; kappa = 0.37; p < 0.01). Analysis of quartiles of change also showed significant better agreement with spine and whole body for the total hip than for the femoral neck or ultradistal (UD) forearm. In a logistic regression analysis for identification of group (HRT or control), the prediction was best for whole body (82.6%) and spine (80.9%), followed by total hip (78.5%) and forearm (74.7%). In conclusion, changes at the commonly measured sites are discordant, and DXA of the forearm is less useful than DXA of the hip or spine in determining the overall skeletal response to therapy or assessing bone loss in untreated women.

The fallacy of BMD: a critical review of the diagnostic use of dual X-ray absorptiometry

The diagnostic use of BMD should be cautious as BMD is not an ideal measure of true bone density; it is not an ideal measure of bone strength; it does not predict fractures well; and it has inherent problems of accuracy and linearity. The limitations of BMD, based on the physical deficiencies of DXA, are further obscured by the introduction of T-scores. It is suggested that BMD and BMC, when used diagnostically and for fracture risk classification, be used after correction for body size and/or bone size, age and sex, and that measured values be evaluated in the light of established mean fracture incidence data. BMD is not a parameter of sufficient validity to be the sole indicator of present and future fracture risk. A low BMD should be regarded one of several fracture risk factors. It seems that there is a need to redefine the T-score based definition of osteoporosis.

Comparison of quantitative ultrasound and dual X-ray absorptiometry in estrogen-treated early postmenopausal women

Identifying individuals at risk of developing osteoporosis is important in order to initiate early treatment. Many new techniques have been proposed as alternatives for DXA-scanning. Some of these alternatives certainly have advantages, but none have so far been demonstrated to predict fractures better, or even to identify individuals at risk of osteoporosis as well as with the standard method. In this study, comprising a group of women from the Danish Osteoporosis Prevention Study, we wished to investigate whether a technique based on quantitative ultrasound (QUS) could identify individuals with low BMC/BMD as measured by dual X-ray absorptiometry (DXA). Furthermore, we wished to test whether the method could detect differences between untreated individuals and those treated with hormone replacement therapy. We found that QUS could detect differences between the treated and untreated groups, but it was unable to identify women with low BMD, although it might be able to identify persons not at risk of osteoporosis. Low QUS values should be followed by a regular DXA measurement to confirm the presence of osteoporosis.

The metacarpal index revisited: a brief overview

Metacarpal index (MCI) is combined cortical thickness (both sides)) normalized with regard to outer bone diameter of the measuring site, the midshaft of the second metacarpal, or the three midmetacarpals of both hands. MCI is reduced with age, particularly in postmenopausal women. It correlates with axial bone mass in group studies. Measurement of the MCI in its modern version, digital X-ray radiogrammetry (DXR), requires only a plain analog radiograph, a PC, a film scanner, and reliable software. MCI can be used diagnostically and longitudinally for monitoring changes. MCI measured with DXR has few problems regarding accuracy and precision errors, and MCI is presently regaining lost territories among tests for quantification of bone mass and bone strength. It can be measured inexpensively and swiftly. MCI and other geometrical variables of bone can be measured on old radiographs, thus enabling estimation of cortical bone loss from the time of earlier recordings.

Geometric properties of distal radius and pathogenesis of Colles fracture: a peripheral quantitative computed tomography study

It is well known among clinicians that Colles fracture patients may have normal projected axial bone mineral density and that bone mass is not synonymous with bone strength. The aim of this work was to investigate whether cross-sectional properties of the distal radius in female patients with recent Colles fracture differ from those of a younger group of normal women without fracture. It was hypothesized that patients with Colles fracture had petite distal radii and that cortical thinning and reduced cortical and trabecular volumetric density are dominant features of this fracture type. We used a multilayer high-precision peripheral quantitative computed tomography (pQCT) device with a long-term precision error of 0.1% for a dedicated phantom during the measurement period (152 d). Clinical measurements were made at an ultradistal site rich in trabecular bone and a less ultradistal site rich in cortical bone. The results show that the following pQCT variables were significantly reduced in the nonfractured radius of the Colles fracture cases: mean ultradistal trabecular volumetric density, mean ultradistal and distal cortical volumetric density, mean ultradistal and distal cortical thickness (p < 0.001 for all differences). The outer cortical diameter, cross-sectional bone area, and cortical bending moment of inertia were not statistically different in the two groups. Thus, it would appear that Colles fracture cases did not have petite distal radii. The results suggest that the deforming force of Colles fracture has a transaxial direction (fall on outstretched arm), resulting in a crush fracture, and that it is not a bending force. We suggest that Colles fracture occurs as a result of the combined effect of a fall on the out-stretched arm, low trabecular and cortical volumetric bone density, and reduced cortical thickness.

Metacarpal index by digital X-ray radiogrammetry: normative reference values and comparison with dual X-ray absorptiometry

Metacarpal index (MCI), the combined cortical midmetacarpal thickness divided by the outer mid-metacarpal diameter, fell into oblivion when dual photon absorptiometry was introduced a quarter of a century ago. Modern PC-based digital X-ray diameter measurements offers a unique opportunity for precise and accurate measurements of MCI (DXR-MCI). We hypothesized that DXR-MCI in contrast to projected areal bone mineral density (BMD) (DXA-BMD) is independent of bone size and studied 384 normal women by measuring DXR-MCI and DXA-BMD of the lumbar spine, hip, and distal radius. A normative MCI database for women is presented. It has its maximum in the third decade, and a moderate biologic variation that seems to decline with age. It was found that DXR-MCI was independent of body weight and body surface area, whereas all DXA-BMD values were significantly dependent on them. Body height was significantly correlated with DXA-BMD at all sites, but less so with DXR-MCI. The latter was correlated with metacarpal bone length. It is suggested that the moderate correlation between MCI and body height would be abolished if the region of interest used for calculation of MCI be adjusted according to individual metacarpal bone length. DXR-MCI correlated significantly with DXA-BMD at the sites measured, and particularly well with that of the distal radius (r = 0.67; p < 0.0001).

Hormonal replacement therapy reduces forearm fracture incidence in recent postmenopausal women - results of the Danish Osteoporosis Prevention Study

OBJECTIVES

To study the fracture reducing potential of hormonal replacement therapy (HRT) in recent postmenopausal women in a primary preventive scenario.

METHODS

Prospective controlled comprehensive cohort trial: 2016 healthy women aged 45-58 years, from three to 24 months past last menstrual bleeding were recruited from a random sample of the background population. Mean age was 50. 8+/-2.8 years, and the number of person years followed was 9335.3. There were two main study arms: a randomised arm (randomised to HRT; n=502, or not; n=504) and a non-randomised arm (on HRT; n=221, or not; n=789 by own choice). First line HRT was oral sequential oestradiol/norethisterone in women with intact uterus and oral continuous oestradiol in hysterectomised women.

RESULTS

After five years, a total of 156 fractures were sustained by 140 women. There were 51 forearm fractures in 51 women. By intention-to-treat analysis (n=2016), overall fracture risk was borderline statistically significantly reduced (RR=0.73, 95% CI: 0.50-1.05), and forearm fracture risk was significantly reduced (RR=0.45, 95% CI: 0.22-0.90) with HRT. Restricting the analysis to women who had adhered to their initial allocation of either HRT (n=395) or no HRT (n=977) showed a significant reduction in both the overall fracture risk (RR=0.61, 95% CI: 0.39-0.97) and the risk of forearm fractures (RR=0.24, 95% CI: 0.09-0.69). Compliance with HRT was 65% after five years.

CONCLUSIONS

It is possible to reduce the number of forearm fractures and possibly the total number of fractures in recent postmenopausal women by use of HRT as primary prevention.

Iodine-129 in human thyroids and seaweed in China

The concentrations of 129I and the ratios of 129I/127I in normal human thyroids collected in Tianjin, China, and some seaweed samples from the Chinese coast were determined by neutron activation analysis. The mean 129I/127I ratio in these thyroids was found to be 1.13 x 10(-9), which is two orders of magnitude higher than the level of the pre-nuclear era, but one order of magnitude lower than the level in Europe in the post-nuclear era. There is no significant difference between the ratio of 129I/127I in the thyroids for the post-nuclear era from China and other areas, which are considered not to have been directly exposed to 129I emission from a nuclear source, such as Chile, Taiwan and Tokyo. The mean 129I/127I ratio in seaweed from the Chinese coast is 2.35 x 10(-10), approximately two orders of magnitude higher than in seaweed collected in the pre-nuclear age, and similar to that from locations without direct exposure to the emission from nuclear installations, influenced only by global fallout. This indicates that the 129I level in China is within the global fallout background level.

Environmental radioactive contamination in Greenland: a 35 years retrospect

Environmental studies of anthropogenic radionuclides in Greenland over four decades are reported. The studies have comprised the marine as well as the terrestrial environments and emphasis has been laid on measurements of 90Sr and 137Cs. The temporal and the spatial trends of these radionuclides are described. The radiation exposure from consumption of locally produced diets has been calculated from consumption rates and the infinite time integrated levels of 90Sr and 137Cs concentrations in the various food products. Compared with most other Arctic people, the Greenlanders have received relatively low doses from anthropogenic radionuclides. There are several reasons for this, first of all, because of the relatively high consumption of marine products compared with terrestrial products. Secondly, because winter slaughtering of reindeer is less frequent in Greenland than in other Arctic countries and Greenland reindeer consume, in general, less lichen than most other Arctic reinder, and thirdly, because the transfer from deposition to lichen in Greenland seems lower than in other Arctic areas.

Mercury in dated Greenland marine sediments

Twenty marine sediment cores from Greenland were analyzed for mercury, and dated by the lead-210 method. In general the cores exhibit a mercury profile with higher mercury concentrations in the upper centimetres of the core. The cores were studied by linear regression of in Hg vs. age of the sediment for the youngest 100 years. As a rule the mercury decreased with depth in the sediment with various degrees of significance. The increase of the mercury flux during the last 100 years is roughly a doubling. The increase may be of anthropogenic origin as it is restricted to the last 100 years. In four cores the concentration of manganese was found also to increase in the top layers indicating diagenesis. In the other cases the higher concentrations were not accompanied by higher manganese concentrations. The mercury flux to the sediment surface was generally proportional to the Pb-210 flux indicating that the mercury mainly originates from atmospheric washout. But the large variability indicates that other processes also influence the mercury flux to Arctic marine sediments.

Validation of a leg-to-leg bioimpedance analysis system in assessing body composition in postmenopausal women

OBJECTIVES

To evaluate the validity of a leg-to-leg bioimpedance analysis (BIA) system in predicting body composition as measured by dual-energy X-ray absorptiometry (DXA) in postmenopausal women.

SUBJECTS AND METHODS

Body fat mass (FM), %Fat and fat free mass (FFM) were measured in 124 postmenopausal women (age: 51-63 y, body mass index (BMI): 17-38 kg/m2) first by the leg-to-leg BIA system, and then by DXA as reference method. Bland-Altman analysis was used to determine the bias and 95% limits of agreement between the two methods for the assessment of the individual. Precision error (CV%) of the BIA system was obtained by repeated measurements with intermediate repositioning.

RESULTS

The leg-to-leg BIA system had a high reproducibility with within-day CVs being 0.6% for FFM and 1.1% for FM, and between-day CVs about twice that. The impedance index (Ht2/Z) obtained by the leg-to-leg BIA was moderately correlated to FFM measured by DXA (r=0.66). A significant, systematic bias was observed between the two methods. The BIA system overestimated FM by a mean of 3.1 kg, and underestimated FFM by 2.7 kg. The analysis of 95% limits of agreement showed that for most individuals, %Fat estimated by the BIA might differ from that measured by DXA by 12% below to 45% above, indicating the lack of agreement between the two methods for the assessment of the individual.

CONCLUSIONS

The leg-to-leg BIA system can provide simple, rapid and highly reproducible measurements of body composition for groups, but it has limited accuracy for the assessment of the individual. Population-specific equations will be needed to improve its accuracy in estimating body composition in postmenopausal women.

Interruption of early pregnancy with mifepristone in combination with gemeprost

BACKGROUND

Mifepristone in combination with prostaglandin has been used since 1988 for induction of early abortion. The aim of the present investigation was to assess the tolerance and efficacy of 600 mg. mifepristone orally followed by gemeprost 1 mg. vaginally either 24 hours (group one) or 48 hours (group two) later.

METHODS

Sixty-four healthy women applying for abortion within the first 8 weeks of pregnancy were randomly allocated to one of the two treatment groups. Intrauterine pregnancy and gestational age were verified by ultrasonography. Symptoms after administration of mifepristone and gemeprost were recorded, and the patients observed at the hospital for at least three hours after prostaglandin-insertion. Blood samples for blood group, hemoglobin, beta-chorion-gonadotrophin, aspartate-aminotransferase and creatinine were drawn.

RESULTS

Outcome was established by gynecological examination, the level of beta-hCG and ultrasonography, at visits one, two and if necessary three to four weeks later. Surgical curettage was performed in case of incomplete abortion, of which there were four in the 24-hour interval group and five in the 48-hour interval group with a success rate (complete abortion) of 55 out of 64 patients (86%).

CONCLUSIONS

There was no difference in efficacy or side effects whether the prostaglandin was administered 24 or 48 hours after mifepristone intake, which suggests that the treatment period can be reduced from the conventional 48 hours.

The radiological exposure of man from radioactivity in the Baltic Sea

A radiological assessment has been carried out considering discharges of radioactivity to the Baltic Sea marine environment since 1950. The sources of radioactivity that have been evaluated are atmospheric nuclear-weapons fallout, fallout from the Chernobyl accident in 1986, discharges of radionuclides from Sellafield and La Hague transported into the Baltic Sea, and discharges of radionuclides from nuclear installations located in the Baltic Sea area. Dose rates from man-made radioactivity to individual members of the public (critical groups) have been calculated based on annual intake of seafood and beach occupancy time. The dose rates to individuals from the regions of the Bothnian Sea and Gulf of Finland are predicted to be larger than from any other area in the Baltic Sea due to the pattern of Chernobyl fallout. The dose rates are predicted to have peaked in 1986 at a value of 0.2 mSv year-1. Collective committed doses to members of the public have been calculated based on fishery statistics and predicted concentrations of radionuclides in biota and coastal sediments. The total collective dose from man-made radioactivity in the Baltic Sea is estimated at 2600 manSv, of which approximately two-thirds originate from Chernobyl fallout, approximately one-quarter from atmospheric nuclear-weapons fallout, approximately 8% from European reprocessing facilities, and approximately 0.04% from nuclear installations bordering the Baltic Sea area. An assessment of small-scale dumping of low-level radioactive waste in the Baltic Sea in the 1960s by Sweden and the Soviet Union has showed that doses to man from these activities are negligible. Dose rates and doses from natural radioactivity dominate except for the year 1986 where dose rates to individuals from Chernobyl fallout in some regions of the Baltic Sea approached those from natural radioactivity.

Marine radioactivity in the Arctic: a retrospect of environmental studies in Greenland waters with emphasis on transport of 90Sr and 137Cs with the East Greenland Current

The waters around Greenland have received radioactive contamination from three major sources: Global fallout, discharges from the nuclear fuel reprocessing plant Sellafield in the UK, and the Chernobyl accident in the Former Soviet Union (FSU). The global fallout peaked in the early 1960s. The radiologically most important radionuclides from this source are 90Sr and 137Cs. The input of global fallout to arctic waters was direct deposition from the atmosphere and indirect delivery through river run off and advection from the Atlantic Ocean via the north-east Atlantic current system. The waterborne discharges from Sellafield which were at their peak between 1974 and 1981 contributed primarily 137Cs, although some 90Sr was also discharged. The Chernobyl accident in 1986 was characterised by its substantial atmospheric release of radiocaesium (134Cs and 137Cs). Other sources may, however, also have contributed to the radioactivity in the Greenland waters. Examples include La Hague, France, and radioactive discharges to the great Siberian rivers (Ob, Yenisey and Lena) from nuclear activities in the Former Soviet Union or the local fallout from the Novaya Zemlya nuclear weapons test site. Dumping of nuclear waste in the Kara and Barents Seas may be another, although minor source. From measurements in Greenland waters carried out since 1962 the transport of radionuclides with the East Greenland Current is calculated and compared with the estimated inputs of 90Sr and 137Cs to the Arctic Ocean. This study focus on 90Sr and 137Cs because the longest time series are available for these two radionuclides.

The Danish Osteoporosis Prevention Study (DOPS): project design and inclusion of 2000 normal perimenopausal women

OBJECTIVE

In 1990 we initiated a 20 year, partly randomised study (Danish Osteoporosis Prevention Study, DOPS) in order to (a) evaluate clinical, biochemical and osteodensitometric variables as predictors of low bone mass and future osteoporotic fractures, and (b) test the hypothesis, that hormone replacement therapy (HRT) initiated shortly after menopause reduces the risk of later osteoporotic fractures. This report describes study design and baseline characteristics of the DOPS-cohort.

METHODS

The study design is pragmatic, attempting to mimic the normal clinical situation. Several HRT alternatives are available according to clinical need. It was considered futile, impractical and unethical to use placebo for 20 years. Instead the study focus on hard endpoints (fractures) confirmed by independent persons (peripheral fractures) or by methods which allow investigator blinding (spinal X-rays). Statistical evaluation will focus on intention to treat analyses evaluating the decision of HRT and it's feasibility. With a compliance of 60% we will have sufficient statistical power (88%) to detect a fracture reduction of 40% in the treatments group. Clinical risk factors, current daily intakes of macronutrients, vitamins and minerals, anthropometric variables, biochemical variables (including bone markers and 25-hydroxyvitamin D), regional bone mineral density (BMD) and total body composition were assessed in all participants at entry and at various follow up intervals.

RESULTS

2016 study participants were recruited by direct mailing to a random sample of 45-58 years old women. In the randomised arm 501 were allocated to HRT and 505 to no treatment. In the non-randomised arm 219 preferred HRT and 791 preferred no treatment. Post-randomisation analysis revealed a slight but significant difference in age (50.01 versus 50.44 years) but no difference in menopausal age, prevalence of hysterectomy, educational level, BMI, serum bone alkaline phosphatase, serum osteocalcin, urine hydroxyproline or serum 25-hydroxyvitamin D. In the non-randomised arm women preferring HRT were closer to menopause, had a higher prevalence of hysterectomy, were better educated, were leaner, and had lower bone turnover than the women, who refused HRT.

CONCLUSION

It is possible to include a sufficient number of perimenopausal women in a randomised 20 year study on the antifracture effect of HRT.

Influence of strontium on bone mineral density and bone mineral content measurements by dual X-ray absorptiometry

The presence of Sr in bone influences bone mineral density (BMD) and content (BMC) measurements by dual-energy X-ray absorptiometry (DXA). This interaction is of interest, since strontium ranelate (S12911) demonstrated positive effects on bone metabolism in various animal models of osteoporosis, and is currently being evaluated for treatment of postmenopausal osteoporosis. The present in vitro study aimed to determine adjustment factors for DXA measurements of BMC and BMD at different Sr concentrations in order to estimate the corresponding values that would have been measured without Sr. A series of mixtures of Ca and Sr hydroxyapatites were prepared, with biologically relevant Sr/Ca ratios ranging from 0 to 3.5 mol/mol%, and a constant total concentration of divalent cations (145 mmol). The mixtures were conditioned in plastic dishes 4.5 cm in diameter, to obtain an areal density close to the human vertebral mineral density of 0.7-1.1 g/cm(2). DXA measurements of the mixtures were made with a wide range of different instruments and various acquisition modes. A direct linear relationship (r(2) > 0.99) was found between strontium content and overestimation of BMD and BMC. There were no significant differences in adjustment factors for BMC or BMD between the different machines or acquisition modes, and the presence of Sr in the water bath used to mimic soft tissues did not affect the accuracy and precision of the method. This demonstrates that reliable DXA determinations of BMD may be carried out in the presence of Sr, and may be interpreted in terms of calcium hydroxyapatite equivalent if the bone Sr content of the measured bone is known. The same adjustment factor (10% overestimation for 1 mol/mol% Sr) can be used for all presently available types of instrument and acquisition modes.

Combined versus sequential hormonal replacement therapy: a double-blind, placebo-controlled study on quality of life-related outcome measures

BACKGROUND

To compare combined and sequential hormonal replacement therapies to each other as well as placebo in patients suffering from the postmenopausal syndrome. Clinical outcomes were measured concerning both the specific postmenopausal symptoms (using the Kupperman scale) and health or well-being dimensions (using subscales of the General Health Questionnaire and specific depression and anxiety scales).

METHODS

A prospective randomized double-blind study over 12 months of 105 normal early postmenopausal women in the setting of a general hospital.

RESULTS

Both hormone replacement therapies were superior to placebo on the Kupperman scale (sweating, hot flushing, myalgia and vertigo). The psychic symptoms on the Kupperman scale were psychometrically invalid. However, psychic symptoms as measured by the Beck Depression Inventory and the General Health Questionnaire were significantly improved by the hormonal replacement therapies. No differences were observed when combined therapy was compared to sequential therapy.

CONCLUSION

One-year treatment with hormonal replacement therapy is superior to placebo in measuring the somatic and psychic symptoms of the menopausal syndrome. No differences were found in this respect between combined and sequential replacement therapy.

Bone mineral changes during pregnancy and lactation: a longitudinal cohort study

1. The influence of pregnancy, lactation and weaning on bone mineral density in healthy women was investigated during a 2 year prospective study of 59 pregnant and lactating women from the 18th week of gestation. 2. Bone mineral density was measured by dual energy X-ray absorptiometry at the non-dominant radius ultra distally and more proximally in the 18th and 37th weeks of gestation, and 0, 3, 6, 12 and 18 months after delivery. Measurements of bone mineral density of the lumbar spine, the proximal femur and the whole body were performed at all dates after delivery. 3. Reappearance of menstruation after delivery averaged 6.1 months; mean lactating period was 8.7 months. During pregnancy and lactation bone mineral density tended to decrease, but different measuring sites showed different patterns of bone mineral density changes. The reduction in the ultra distal radius during pregnancy amounted to 2%, and no further changes were observed here during lactation. After delivery, reduction in mean bone mineral density was most pronounced in the spine (5.2% in 3 months), but the fall in bone mass tended to revert after resumption of menstruation. Bone mineral density was still reduced by 3.3% after 12 months in women with menstruation resumption later than 8 months after delivery. No significant reduction was observed 18 months after delivery. No association with calcium intake, weight changes or initial bone mineral density was observed. High calcium intake did not protect against bone mineral loss in the spine and the femur. 4. Thus it can be concluded that bone loss during pregnancy and lactation took place mainly from the trabecular skeleton. Resumption of menstruation tended to result in a regain of bone mass towards baseline.

Benchmarking of numerical models describing the dispersion of radionuclides in the Arctic Seas

As part of the International Arctic Seas Assessment Project (IASAP) of the International Atomic Energy Agency (IAEA), a working group was created to model the dispersal and transfer of radionuclides released from radioactive waste disposed of in the Kara Sea. The objectives of this group are: (1) development of realistic and reliable assessment models for the dispersal of radioactive contaminants both within, and from, the Arctic ocean; and (2) evaluation of the contributions of different transfer mechanisms to contaminant dispersal and hence, ultimately, to the risks to human health and environment. With regard to the first objective, the modelling work has been directed towards assessment of model reliability and asone aspect of this, a benchmarking exercise has been carried out. This paper briefly describes the benchmark scenario, the models developed and used, and discusses some of the benchmarking results. The role of the exercise within the modelling programme of IASAP will be discussed and future work described.

Collective doses to man from dumping of radioactive waste in the Arctic Seas

A box model for the dispersion of radionuclides in the marine environment covering the Arctic Ocean and the North Atlantic Ocean has been constructed. Collective doses from ingestion pathways have been calculated from unit releases of the radionuclides 3H, 60Co, 63Ni, 90Sr, 129I, 137Cs, 239Pu and 241Am into a fjord on the east coast of NovayaZemlya. The results show that doses for the shorter-lived radionuclides (e.g. 137Cs) are derived mainly from seafood production in the Barents Sea. Doses from the longer-lived radionuclides (e.g. 239Pu) are delivered through marine produce further away from the Arctic Ocean. Collective doses were calculated for two release scenarios, both of which are based on information of the dumping of radioactive waste in the Barents and Kara Seas by the former Soviet Union and on preliminary information from the International Arctic Sea Assessment Programme. A worst-case scenario was assumed according to which all radionuclides in liquid and solid radioactive waste were available for dispersion in the marine environment at the time of dumping. Release of radionuclides from spent nuclear fuel was assumed to take place by direct corrosion of the fuel ignoring the barriers that prevent direct contact between the fuel and the seawater. The second scenario selected assumed that releases of radionuclides from spent nuclear fuel do not occur until after failure of the protective barriers. All other liquid and solid radioactive waste was assumed to be available for dispersion at the time of discharge in both scenarios. The estimated collective dose for the worst-case scenario was about 9 manSv and that for the second scenario was about 3 manSv. In both cases, 137Cs is the radionuclide predicted to dominate the collective doses as well as the peak collective dose rates.

Effects on bone mass after eight years of hormonal replacement therapy

OBJECTIVE

The purpose of this randomised double-blind placebo-controlled study over two years followed by a six year open controlled extension phase was to investigate the effects of hormonal replacement therapy (HRT) both continuous combined HRT and sequential HRT) versus no treatment on lumbar spine bone mineral density (L-BMD) and distal forearm bone mineral content (F-BMC). Further, bone mineral density of the proximal femur, lateral spine, and distal forearm was studied after eight years.

DESIGN

Prospective study of normal, early postmenopausal women, initially in a double-blind, placebo controlled study, subsequently an open, controlled investigation.

SETTING

Clinical physiology unit of a general second degree referral hospital.

SAMPLE

Seventy-three normal, early postmenopausal women (HRT n = .47; placebo/untreated n = 26).

METHODS

Dual photon absorptiometry, dual X-ray absorptiometry, single photon absorptiometry.

MAIN OUTCOME MEASURES

HRT resulted in a significantly (P < 0.001) higher mean L-BMD after eight years, when it was 12.1% higher than the mean initial value and 14.8% higher than the mean bone mineral density of the untreated group. L-BMD increased by 14.6% in women receiving continuous combined HRT compared with 11.1% in those on sequential HRT but intergroup differences were not statistically significant. Mean F-BMC measured with SPA decreased in the HRT group and in the placebo/untreated group by 0.2% and 14.8% (P < 0.001), respectively. However, after eight years mean F-BMC was 14.5% higher in the HRT group than in the placebo/untreated group. The study showed after eight years for all regions of the distal radius and ulna a significantly higher bone mineral density value compared with the placebo/untreated group (P < 0.001). An especially large effect of HRT was found on the bone mineral density of the vertebral body of the 3rd lumbar vertebra (L3), this one, measured by lateral scanning, being 18.7% higher than that of the placebo/untreated group. For the proximal femur, only the bone mineral density of Ward's triangle was significantly higher in the HRT group than in the placebo/untreated group.

CONCLUSION

Eight years of treatment with HRT resulted in a significant, substantial gain of bone mineral density in the lumbar spine. The distal radius, ulna and Ward's triangle showed a significantly higher bone mineral density in the HRT group compared with the placebo/untreated group.

Effect of 10 years' hormone replacement therapy on bone mineral content in postmenopausal women

The purpose of this study was to investigate the effects of 10 years of hormone replacement therapy (HRT) in postmenopausal women on bone mineral density of the lumbar spine (L-BMD) and bone mineral content of the distal forearm (F-BMC). A total of 151 women were enrolled in the study, 100 of whom were randomized to receive oral HRT (equally divided between a continuous combined and a sequential treatment regimen), with the remaining 51 receiving placebo or no treatment. The study was double-blind for the first 24 months, followed by 8 years of open-label follow-up. Total treatment duration was 10 years. At the end of 10 years, 38% of women randomized to continuous combined HRT remained on therapy compared with 22% of those who had received sequential HRT and 49% of the untreated group. A further 18% of women originally randomized to HRT had switched to other regimens. After 10 years of therapy, L-BMD was found to be significantly higher in HRT-treated women than in those who remained untreated (14.5%; p < 0.001), corresponding to an increase in L-BMD of 13.1% from baseline values on HRT compared with a reduction in L-BMD of 4.7% without therapy. L-BMD increased by 15.9% in women receiving continuous combined therapy compared with 11.1% in those on sequential HRT; however, intergroup differences were not statistically significant. F-BMC decreased by 0.7% over the 10 year period in the HRT treatment groups compared with a reduction of 17.6% in untreated women (p < 0.001). Mean F-BMC was 20.3% higher in women who had received HRT than in those who had not received therapy at the end of the 10 year follow-up. In conclusion, 10 years of treatment with HRT resulted in a substantial increase in L-BMD, with F-BMC also significantly higher in the HRT group than in untreated women. These results confirm that long-term HRT exerts a continuous effect against bone loss in postmenopausal women.

Multiparity and bone mass

OBJECTIVE

To investigate the influence of multiparity on bone mass of the axial skeleton in a population of women of high parity.

DESIGN

Open study of Omani women.

SETTING

Medical physics department and clinical physiology department of a third degree referral (university) hospital.

PARTICIPANTS

A consecutive series of 159 normal women referred with low back pain over a period of six months.

RESULTS

The bone mineral density was measured with dual-photon absorptiometry and the mean was found to be 0.984 (+/-0.166) (+/- SD) g cm-2. The age ranged from 20 to 70 years with a mean age of 43.4 (+/- 12.5) years. The number of children per woman ranged from 0 to 14 with a mean of 5.1 (+/- 3.5). There was no statistically significant influence of the number of children per woman on bone mineral density but there was a strong correlation with age and body size variables.

CONCLUSION

Multiparity does not influence lumbar spine bone mineral density in normal women.

Ultrasound measurements of the os calcis. Side differences and prediction of bone density in 39 persons

We measured the ultrasound Stiffness Index (SI) of the os calcis bilaterally with the Achilles Ultrasound Bone Densitometer in 30 women and 9 men, aged 53 (31-76) years. Lumbar spine BMD (percent of mean per age group) was measured with a DXA bone densitometer. Supplementary BMD measurements of the hip and the nondominant radius were made in 29 of the 39 persons; 11 of them had had a unilateral total hip arthroplasty (THA), the rest were healthy control subjects. SI values were in the range of 78-138 percent. Large individual differences between the right and the left os calcis were seen, even in healthy controls (CV 6.3 percent), although no differences between the means of the two sides were found. The prediction of SI of one os calcis from that of the other was inaccurate (SEE 6 percent). The SI of the dominant os calcis correlated significantly to the lumbar spine BMD, to the hip BMD and to the non-dominant radius BMD. In the group with unilateral THA the individual SI side-differences were larger (CV 8 percent; SEE 9 percent), but no systematic difference between the means of the operated and non-operated sides was found. We conclude that there are large random individual differences between the SI of the right and the left os calcis and recommend measurement of both sides for classification of one individual.