90Sr data

With these circulation features in mind, the apparent stratospheric residence times deduced from the tungsten tracer data (9), the cosmic ray spallation product distribution (2), and the 90Sr concentration variations displayed by recent balloon samples (23) can be placed in better perspective. 

Correlation of 90Sr and 91Y Data. With regard to these nuclides, there is a third set of data to consider along with the data from Laboratories A and B. The laboratory responsible for the third set, Laboratory... 

C, determined only 89Sr, 90Sr, 91Y, and 95Zr. The samples supplied to them were the same kind supplied to Laboratories A and B and should have shown the same fractionation behavior. It is unfortunate that there is no way of verifying the reliability of the 95Zr data from Laboratory C,... 

The data show that the specific activity is generally not a simple function of particle size, confirming the composite nature of the samples. The sharp decrease of the 147Pm specific activities in coral burst samples toward large particle sizes is particularly significant. Systematic differences as a function of yield or soil type between refractory 147Pm behavior and semivolatile 90Sr behavior are not apparent. Uranium behaves very much like "Sr. 

Transfer coefficients can also be deduced from statistics of the levels of 90Sr and 137Cs in milk measured during monitoring of the fallout from nuclear weapon tests. This has the advantage over experimental work of taking into account variations in agricultural practices, but introduces complications such as the use of root crops and imported feed for cattle and the uptake by crops from the soil of activity deposited in previous years. UNSCEAR (1977) analysed data from a number of countries, obtained in the years 1958-74, in the form,... 

Data Table 13.1 Data 89Sr, 90Sr, and 90Y count rates... 

Calculation of the 90Sr concentration from yttrium precipitation and 90 Y counting data... 

Sr on the basis of the 90Y ingrowth. Count the two filters with 89Sr to calculate the counting efficiency and observe the radioactive decay of the radionuclide. Record the gross count rates and background count rate in Data Table 13.4. 

The Techa River population exposed to chronic combined external gamma radiation and internal radiation due to 90Sr and 137Cs exhibited alterations in hematological parameters, including leukopenia, thrombocytopenia, and granulocytopenia (Akleyev et al. 1995). These effects were observed in a portion of the exposed population that received radiation doses to the bone marrow at rates in excess of 30-50 rem (0.3-0.5 Sv) per year. These data are omitted from Table 3-3 because exposures were to multiple sources of radiation. 

Strontium released into the atmosphere from natural and anthropogenetic activities is transported and redeposited on the earth by dry or wet deposition. Dry deposition results from gravitational settling, impact, and sorption on surfaces (NCRP 1984). Experimental data on dry deposition of strontium, present in the ambient atmosphere, is limited. Rain, sleet, snow, or other forms of moisture can wash airborne particles containing strontium from the atmosphere by the process of wet deposition. Wet deposition depends on conditions such as particle solubility, air concentration, rain drop size distribution, and rain fall rate (NCRP 1984). Hirose et al. (1993) examined the mechanism of aerial deposition of 90Sr derived from the Chernobyl accident, and found that 96% of atmospheric 90Sr returned to earth as wet deposition. 

Exposure Levels in Environmental Media. Information about concentrations of strontium and 90Sr in air, water, soil, and food are available. However, updated information on the concentration levels in air, soil, and food may be useful. Specific monitoring of 90Sr in airborne particulates may also be beneficial. Reliable monitoring data for the levels of 90Sr in contaminated media at hazardous waste sites may be useful so that the information obtained on levels of 90Sr in the environment can be used in combination of the known body burden with strontium to assess the potential risk of adverse health effects in populations living in the vicinity of hazardous waste sites. 

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