228Ra and 226Ra Content of Groundwater in Fall Line Aquifers
1980; Lippincott Williams & Wilkins; Volume: 38; Issue: 4 Linguagem: Inglês
10.1097/00004032-198004000-00014
ISSN1538-5159
AutoresJacqueline Michel, Willard S. Moore,
Tópico(s)Nuclear and radioactivity studies
ResumoStudies of the radium isotopic content of groundwater from a Coastal Plain aquifer adjacent to the Fall Line in South Carolina show that elevated 228Ra and 226Ra concentrations are associated with the aquifer. There is little seasonal variation in the concentration of either radium isotope for a single well, but up to an order of magnitude variation among wells within a 4 km2area (228Ra activities range from 4.71 to 11.9 pCi/l. whereas 226Ra activities range from 2.71 to 26.53 pCi/l.). The 228Ra/ 226Ra activity ratio among wells ranges from 0.23 to 3.0, and is inversely proportional to 226Ra content. These results are contrary to the assumption in the U.S. Environmental Protection Agency drinking water regulations which state that 228Ra rarely exceeds 226Ra and thus require 228Ra measurements only when 226Ra exceeds 3.0 pCi/l. It is unknown whether these results are typical for all Fall Line aquifers of the southeastern U.S., which extend from Alabama to Maryland and supply water to many small towns, However, these results, which show that the 226Ra concentration does not parallel 228Ra concentration in this geologic region, call for a re-examination of the EPA regulation.
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