along the coastline is diluted by
freshwater and contains the radioactive isotope radium 226, which erodes off
sediment encountered by
rivers and groundwater. Since the radium concentrations in
rivers are well established, unusually high radium levels in coastal waters indicated
to Moore that there had to be another source of freshwater. To determine just
how much groundwater was flowing into the ocean, Moore examined the chemistry
of the freshwater entering the ocean along 200 miles of the South Carolina coast.
diluted = mixed concentrations
Moore believed that oceans had another source of freshwater besides rivers because he found low concentrations of radium in coastal waters.