Dust fallout

Gulson BL, Davis JJ, Mixon KJ, Dorsch MJ and Bawden-Smith j (1995) Sources of lead in soil and dust and the use of dust fallout as a sampling medium. Sci Total Environ 166 245-262. 

Gulson BL, Davis JJ, Mizon KJ et al (1995a) Sources of lead in soil and dust and the use of dust fallout as a sampling medium. Sci Total Environ 166 245-262 Gulson BL, Mahaffey KR, Mizon KJ et al (1995b) Contribution of tissue lead to blood lead in adult female subjects based on stable lead isotope methods. J Lab Clin Med 125 703-712 Hageman KJ, Simonich SL, Campbell DH et al (2006) Atmospheric deposition of current-use and historic-use pesticides in snow at national parks in the western United States. Environ Sci Technol 40 3174-3180... 

During the second and third Gulf Wars (1990-1991 and 2003), the main components of the terrestrial ecosystem especially soil were severely damaged by military operations. These operations have different impacts on the various parts of the terrestrial ecosystem depending on the timing, magnitude, and goals of military operations as well as the local physical conditions. The impacts of military operations are differentiated into onsite and offsite. The onsite impacts include terrain deformation and depletion of resources. The offsite impacts involve increase of the rates of sand transport and dust fallout. 

Half-lives span a very wide range (Table 17.5). Consider strontium-90, for which the half-life is 28 a. This nuclide is present in nuclear fallout, the fine dust that settles from clouds of airborne particles after the explosion of a nuclear bomb, and may also be present in the accidental release of radioactive materials into the air. Because it is chemically very similar to calcium, strontium may accompany that element through the environment and become incorporated into bones once there, it continues to emit radiation for many years. About 10 half-lives (for strontium-90, 280 a) must pass before the activity of a sample has fallen to 1/1000 of its initial value. Iodine-131, which was released in the accidental fire at the Chernobyl nuclear power plant, has a half-life of only 8.05 d, but it accumulates in the thyroid gland. Several cases of thyroid cancer have been linked to iodine-131 exposure from the accident. Plutonium-239 has a half-life of 24 ka (24000 years). Consequently, very long term storage facilities are required for plutonium waste, and land contaminated with plutonium cannot be inhabited again for thousands of years without expensive remediation efforts. 

Denmark 1.5 days after the explosion. Air samples collected at Roskilde, Denmark on April 27-28, contained a mean air concentration of 241Am of 5.2 pBq/m3 (0.14 fCi/m3). In May 1986, the mean concentration was 11 pBq/m3 (0.30 fCi/m3) (Aarkrog 1988). Whereas debris from nuclear weapons testing is injected into the stratosphere, debris from Chernobyl was injected into the troposphere. As the mean residence time in the troposphere is 20-40 days, it would appear that the fallout would have decreased to very low levels by the end of 1986. However, from the levels of other radioactive elements, this was not the case. Sequential extraction studies were performed on aerosols collected in Lithuania after dust storms in September 1992 carried radioactive aerosols to the region from contaminated areas of the Ukraine and Belarus. The fraction distribution of241 Am in the aerosol samples was approximately (fraction, percent) organically-bound, 18% oxide-bound, 10% acid-soluble, 36% and residual, 32% (Lujaniene et al. 1999). Very little americium was found in the more readily extractable exchangeable and water soluble and specifically adsorbed fractions. 

Merk, I. (1967). Fallout in Rain, Dust, and Soil and Its Absorption in Plants, Report No. EIR-103 (Eidgenoessisches Institut fuer Reaktorforschung, Wuerenlingen, Switzerland). 

This paper deals mainly with the condensation of trace concentrations of radioactive vapor onto spherical particles of a substrate. For this situation the relation between the engineering approach, the molecular approach, and the fluid-dynamic approach are illustrated for several different cases of rate limitation. From these considerations criteria are derived for the use of basic physical and chemical parameters to predict the rate-controlling step or steps. Finally, the effect of changing temperature is considered and the groundwork is thereby laid for a kinetic approach to predicting fallout formation. The relation of these approaches to the escape of fission products from reactor fuel and to the deposition of radon and thoron daughters on dust particles in a uranium mine is indicated. 

Figure 15 shows the close-in fallout collection array (NRDL) and the radiation pattern at 1 hour. The first three numbers of the close-in samples correspond to the numbers of the stations shown here. The letters AO and PC indicate always-open collectors and platform collectors, respectively. These collectors were identical, but the PC collectors received better protection from dust prior to shot time. The next number indicates which of the 9 or 16 pans in the array has been taken. Additional numbers indicate sieve sizes retaining the debris. 

Land releases of radium are related to atmospheric fallout of coal fly ash (see Section 5.2.1). For example, elevated radium-226 concentrations in snow have been detected near a coal-fired power plant in Poland (Jaworowski et al. 1971). Other land releases may include the disposal of coal fly ash, lime slurry derived from water softening processes, and uranium mine tailings and associated wind-blown dusts. However, no information was located on the total amount of land-released radium... 

If we assume that a fallout rate of cosmic dusts has been constant and 3He in sediments is entirely due to cosmic dusts, a 3He concentration in sediment can be expressed as a function of sedimentation rate (r) and of a cosmic dust fall-out flux (F),... 

In addition to direct contact with the pesticide, indirect exposure is also likely through such actions as brushing against plants, animals, or other items just treated with pesticides or from overhead fallout of pesticide, such as mists, drips, or dusts. 

Fallout, rain water, dust Monthly Nuclide analysis Basin method... 

The role of the atmosphere in the phosphorus cycle seems to be poorly understood. Since it does not exist in the form of stable gaseous compounds, phosphorus in the atmosphere is either adsorbed on particulate matter, e.g. dust (including pollen) and exhaust fumes or dissolved in sea-spray. The fallout of phosphorus, as dry deposition and precipitation, has been estimated to be within the range 3.6—9.2 Tg P y for terrestrial ecosystems, 0.054— 0.140 Tg P y for freshwater ecosystems, and 2.6—3.5 Tg y" for the marine ecosystem. This gives a total fallout from the atmosphere of 6.3—12.8 Tg P y i (Pierrou, 1976). It should be noted, however, that Emery et al. (1955)... 

Strontium is a naturally occurring element found in rocks, soil, dust, coal, and oil. Naturally occurring strontium is not radioactive and is referred to as stable strontium. Stable strontium in the environment exists in four stable isotopes, " Sr (read as strontium 84), Sr, Sr, and Sr. Twelve other unstable isotopes are known to exist. Its radioactive isotopes are Sr and °Sr. Strontium is chemically similar to calcium. It was discovered in 1790. The isotope Sr is a highly radioactive poison, and was present in fallout from atmospheric nuclear explosions and is created in nuclear reactors. Atmospheric tests of nuclear weapons in the 1950s resulted in deposits and contaminations. °Sr has a half-life of 28 years and is a high-energy beta emitter. Its common cationic salts are water soluble it forms chelates with compounds such as ethylenediaminetetraacetic acid strontium coordination compounds are not common. Powdered metallic strontium may constitute an explosion hazard when exposed to flame. 

---