![]() The most significant water-related releases of radium may be from the leaching of uranium mine tailings and from the release of ore-processing effluents generated by leaching, decantation, and filtration processes. Radium-226 has been detected in soils in industrial regions at levels up to 8.1 pCi/g (0.30 Bq/g) ( Jaworowski and Gryzbowska 1977). Eisenbud and Petrow (1964) estimated that a single 1000-megawatt coal-fired power plant will discharge about 28 mCi (1,037,000 kBq) of total radium per year. If it is assumed that the total radium content of fly ash is 5 pCi/g (0.19 Bq/g), and that 1% of the ash generated at all coal-fired power plants in the United States escapes into the atmosphere, then an order-of-magnitude estimate of the amount of radium released each year would be 2.2 Ci (81,000,000 kBq) ( Roy et al. The radium-228 content of fly ash has varied from 1.8 to 3.1 pCi/g (0.07 to 0.12 Bq/g) ( Eisenbud and Petrow 1964). 1978 Eisenbud and Petrow 1964 Morris and Bobrowski 1979). The concentrations of radium-226 in fly ash have ranged from 1 to 10 pCi/g (0.04 to 0.4 Bq/g) ( Coles et al. When combusted, radium may volatilize, then condense onto coal fly ash particles, which in turn may be released from power plants as fugitive emissions. The mean concentration of radium-226 in coal is on the order of 1 pCi/g (0.04 Bq/g). The combustion of coal may be the most important mechanism for releasing radium into the atmosphere. The frequency of NPL hazardous waste sites in the United States at which radium has been found at higher than background levels can be seen in Figure 5-1. Radium may be bioconcentrated and bioaccumulated by plants and animals, and it is transferred through food chains from lower trophic levels to humans. The concentrations of radium-226 and radium-228 in drinking water are generally low, but there are specific geographic regions where high concentrations of radium occur due to geologic sources. Radium does not degrade other than by radioactive decay at rates which are specific to each of four naturally-occurring isotopes. ![]() In addition, radium is constantly being produced by the radioactive decay of its precursors, uranium, and thorium. The concentration of radium in natural water is usually controlled by adsorption-desorption reactions with minerals and rocks and by the solubility of radium-containing minerals. The utilization of radium, uranium, and fossil fuels has resulted in the redistribution of radium in the environment by way of air, water, and land releases. Radium is a naturally-occurring metal that is almost ubiquitous in soils, water, geologic materials, plants, and foods at low concentrations.
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