Radium fluxes from a salt marsh

In this present study Bly Creek, a small marsh-tidal creek system near Georgetown, South Carolina, was chosen to determine the flux of 228Ra and 224Ra, from the sediments to the tidal creek water. The highest activities of 224Ra and 228Ra found in the tidal creek waters occur during low tide, but 226Ra activity remains relatively constant throughout the tidal cycle. Fluxes of 224Ra and 228Ra calculated from mass balances required to support the observed activities in the creek waters and measured directly using a flux chamber are consistent. These measurements reveal a large input of radium from the marsh sediments to the overlying waters. To produce the necessary fluxes, irrigation and bioturbation must replace interstitial water in the top 5 cm of the marsh sediments every 2-3 days. (author)