Search

Rationale Strontium isotope ratios (87Sr/86Sr) in modern‐day marine environments are considered to be homogeneous (~0.7092). However, in the Baltic Sea, the Sr ratios are controlled by mixing seawater and continental drainage from major rivers discharging into the Baltic. This pilot study explores if variations in Sr can be detected in marine mammals from archaeological sites in the Baltic Sea. Methods 87Sr/86Sr ratios were measured in tooth enamel from three seal species by laser ablation multi‐collector inductively coupled plasma mass spectrometry (LA‐MC‐ICP‐MS). The method enables micro‐sampling of solid materials. This is the first time that the method has been applied to marine samples from archaeological collections. Results The analyses showed inter‐tooth 87Sr/86Sr variation suggesting that different ratios can be detected in different regions of the Baltic Sea. Furthermore, the intra‐tooth variation suggests possible different geographic origin or seasonal movement of seals within different regions in the Baltic Sea through their lifetime. Conclusions The method was successfully applied to archaeological marine samples showing that: (1) the 87Sr/86Sr ratio in marine environments is not uniform, (2) 87Sr/86Sr differences might reflect differences in ecology and life history of different seal species, and (3) archaeological mobility studies based on 87Sr/86Sr ratios in humans should therefore be evaluated together with diet reconstruction.

Results of a somewhat preliminary bioanthropological study on the skeletal material from the Pitted ware site of jettböle, excavated in the parish of jomala, Aland (Ahvenanmaa) Islands, some 85-90 years ago are presented, and the causes for the disorderly distribution, including the possibility of cannibalism, are discussed.

The use of a vertically mounted Ge(Li)-detector for gamma spectrometric measurements in the field is described in detail. During measurement the portable detector assembly is mounted on a tripod at a distance of 1 m above ground. All electronic equipment is shockmounted inside a vehicle which makes transportation on moderately rough ground possible. The calculation of the detector response for primary photons originating from gamma emitting radionuclides in the ground is described. Corrections for soil water content, air humidity, pressure and temperature are included. The equipment has successfully been used for long-term field measurements during varying weather conditions.

A study of the absorption of vitamin B12 labelled with 57Co was performed by whole-body counting. The subjects were measured in prone and supine positions by a NaI(Tl) scintillation detector which moved l50 cm along the subject. The technique was evaluated by model studies, by whole-body counting of subjects and by radioactivity assay of excreta. The influence of body size upon the whole-body counter sensitivity was demonstrated. This influence was considerably diminished when the Compton energy range instead of the photopeak energy range was used for the determination of the radioactivity in the body.

The present study concerns the determination of fluorine, iodine, lead and mercury by means of the photonuclear activation techinique with a betatron. The detection limits obtained for the elements in the above sequence were 3, 50, 400 and 15 μg respectively. The technique has been applied in the determination of iodine in pharmaceuticals. A rotating sample holder device was inserted in the bremsstrahlung beam of the betatron in order to ensure uniform irradiation of the samples.

A whole-body counter for determination of body burdens of Cs/sup 137/ and other isotopes is described. The counter, easily assembled and disassembled, has small dimensions and the weight is less than 1500 kg. The background reduction is obtained by lead shielding. Effect on the background of the nadioactive environment and of the size of the subject was studied. The measuring geometry, a 5 in. x 4 in. NaI(Tl) crystal in a 42 cm chair geometry, has been calibrated by comparison with a static iron-room counter. The sensitivity is 2.76 cpm/nC/sup 137/Cs. Measuring accuracy as a function of body burden and background is analyzed. (auth)

The spectral distribution and the total energy of the internal bremsstrahlung of ${\mathrm{P}}^{32}$ were measured from 20 to 1000 kev with a NaI(Tl) scintillation spectrometer. Special care was taken to diminish and correct for bremsstrahlung from the apparatus and the surroundings. The experimental curve agrees with theory from 20 to 50 kev and in the region 50-120 kev shows a weak bump in a smoothed curve; from 120 to 500 kev the curve lies 15 percent, at 800 kev 45 percent, and at 1000 kev 70 percent above a theory based on allowed $\ensuremath{\beta}$ transition; thus, above 120 kev, the experimental curve disagrees with the theory for both allowed and forbidden $\ensuremath{\beta}$ transitions. The total energy per $\ensuremath{\beta}$ decay in the internal bremsstrahlung was found to exceed the calculated value by 21 percent.Using the same experimental arrangements the external bremsstrahlung emitted when the ${\mathrm{P}}^{32}$ $\ensuremath{\beta}$ rays are completely stopped in carbon, aluminum, iron, tin, and lead was also measured. For light elements the observed spectrum was found to agree closely with the theory by Bethe and Heitler as improved by Elwert, but for heavy elements and high energies to exceed the calculated values considerably, e. g., for lead at 500 and 1000 kev by a factor of 1.4 and 2.0, respectively.

After a considerable time spent on preparatory work, the International Commission on Radiation Units and Measurements (I.C.R.U.) over the period 1953–62 presented its definitions of the quantities absorbed dose, exposure and activity and the corresponding special units 1 rad, 1 rontgen (1R) and 1 curie (1 Ci). They are now generally accepted in the whole field of radiology and radiation protection for routine use although certain misuse of some of these quantities is still noticed.

The International System of Units (SI) is a practical system of units of measurement suitable for adoption by all signatories to the Metre Convention. While the general implementation of SI means new difficulties in the future use of the special radiological units, the units curie, rontgen, and rad can all be exactly expressed in SI units. A table shows the conversion factors which indicate that the SI units imply substantial changes in the numerical values of the actual quantities. It may be that some of the problems involved may be solved by introducing new names for the derived SI units.

Accumulation, retention and internal cycling of the fallout radionuclide 137Cs (physical half-life = 30.2 a) was studied in forest moss Pleurozium schreberi (Brid.) Mitt. collected in southern Sweden during the period 1961-1973. The highest 137Cs concentrations occurred in the green top parts of the living moss. A major part of the deposited 137Cs is available for transport from the dying to growing parts of the moss. Elimination of 137Cs from living moss, as well as from dead moss, throughout 1968-1973, can be characterized by the same mean residence time (4 ? 1 a). 137Cs and naturally occurring stable K show different behaviour in the moss, so that the 137Cs/K ratio is higher by a factor of approximately 2 in the dead parts of the moss than in the living parts. The vertical distribution of 137Cs in the moss-covered ground,has been described theoretically. Relative penetration of 137Cs is about 5 times higher in ground covered by mosscarpets than in ground covered by lichen-carpets. Throughout 1969-1973, the total amount of '37Cs retained in the moss-carpet was 64.2 ? 2.2 nCi m-2.

Lichens of the genus Cladonia, mainly C. alpestris, collected during 1882-1972 were analyzed for stable lead and 210Pb. The specific activity of 210Pb (210Pb/Pb ratio) indicates a constant value of about 2 mCi/kg up to 1940, and then decreased to 0.6 mCi/kg during 1950-1960. As the average annual 210Pb deposition is relatively constant, the decrease in the 210Pb/Pb ratio after 1940 indicates an increased deposition of stable lead after 1940. A single exponential variation of the 210Pb/Pb ratio, in respect to latitude, was found in lichens collected in 1964. Values for 210Pb and stable lead in C. alpestris, collected in central Sweden during 1961-1972, appear to be relatively constant and the average area content of 210Pb and stable lead in lichen carpets was 15 ± 2 nCi/m2 and 25 ± 5 mg/m2 respectively. The pattern of vertical distribution was converted to a model for the translocation of lead in lichens, which included the diffusion principle. The diffusion coefficient for lead in the top layer of the lichen carpet was estimated to be about (0.2 ± 0.1) x 10-6 cm2 x s-1. (Less)

The publication of my letter “SI Units in Radiology and Radiation Measurement” in your journal (Liden, 1973) was appreciated by the International Commission on Radiation Units and Measurements, ICRU. The interest of many readers has obviously been awakened by this letter, which also appeared in several other journals. By October 10, 1973 the ICRU had received about 30 written comments from organizations and individuals. Even more comments will no doubt be received in the near future.

The publication of my letter “SI Units in Radiology and Radiation Measurement” in your journal (Liden, 1973) was appreciated by the International Commission on Radiation Units and Measurements, ICRU. The interest of many readers has obviously been awakened by this letter, which also appeared in several other journals. By October 10, 1973 the ICRU had received about 30 written comments from organizations and individuals. Even more comments will no doubt be received in the near future.