Occurrence and geochemistry of radium in water from principal drinking-water aquifer systems of the United States |
| |
| Authors: | Zoltan Szabo Vincent T dePaul Jeffrey M Fischer Thomas F Kraemer Eric Jacobsen |
| |
| Institution: | 1. US Geological Survey, 810 Bear Tavern Rd., W. Trenton, NJ 08628, United States;2. US Geological Survey, 12201 Sunrise Valley Rd., Reston, VA 20192, United States |
| |
| Abstract: | A total of 1270 raw-water samples (before treatment) were collected from 15 principal and other major aquifer systems (PAs) used for drinking water in 45 states in all major physiographic provinces of the USA and analyzed for concentrations of the Ra isotopes 224Ra, 226Ra and 228Ra establishing the framework for evaluating Ra occurrence. The US Environmental Protection Agency Maximum Contaminant Level (MCL) of 0.185 Bq/L (5 pCi/L) for combined Ra (226Ra plus 228Ra) for drinking water was exceeded in 4.02% (39 of 971) of samples for which both 226Ra and 228Ra were determined, or in 3.15% (40 of 1266) of the samples in which at least one isotope concentration (226Ra or 228Ra) was determined. The maximum concentration of combined Ra was 0.755 Bq/L (20.4 pCi/L) in water from the North Atlantic Coastal Plain quartzose sand aquifer system. All the exceedences of the MCL for combined Ra occurred in water samples from the following 7 PAs (in order of decreasing relative frequency of occurrence): the Midcontinent and Ozark Plateau Cambro-Ordovician dolomites and sandstones, the North Atlantic Coastal Plain, the Floridan, the crystalline rocks (granitic, metamorphic) of New England, the Mesozoic basins of the Appalachian Piedmont, the Gulf Coastal Plain, and the glacial sands and gravels (highest concentrations in New England). |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
