Chemical oceanographers Margaret K. Scott and S. Bradley Moran at the University of Rhode Island’s Graduate School of Oceanography have estimated the input of ground water to coastal systems by measuring naturally occurring radium-226 (226Ra) as a ground water tracer.
In a recent study, reported in the Journal of Environmental Radioactivity, Scott and Moran collected and analyzed water samples from Rhode Island salt ponds and several local residential drinking wells, as well as sediment cores from each pond to determine how much 226Ra was present in the water and sediments.
The radioactive element radium was discovered in 1898 by Marie and Pierre Curie in pitchblende (or uraninite) from North Bohemia. It is commonly used to make self-luminous paints, as a neutron source, and for the treatment of conditions such as cancer. It is a white alkaline earth metal that tarnishes black upon exposure to air. It luminesces, decomposes in water, emits radioactive radon gas, disintegrates radioactively until it reaches stable lead, and is a radiological hazard. With a half-life of 1,600 years, radium is more than a million times more radioactive than the same mass of uranium (http://www.webelements.com).
Scott and Moran, funded by the Rhode Island Sea Grant Program, found that using 226Ra as a tracer of ground water input yielded results that were comparable to previous estimates of ground water input to these ponds. The scientists calculated that the imbalance between the amount of 226Ra going into and being discharged from the salt ponds indicated an additional source of radium to the ponds, which they determined to be ground water.
“Quantifying the input of ground water and associated chemicals, such as nutrients, to the state’s coastal waters is important for developing a better understanding of the harmful effects of natural and man-made inputs and improving coastal zone management,” said Moran. "Our most recent research has focused on seasonal variations in the input of groundwater and associated nutrients to these coastal ecosystems."
The URI Graduate School of Oceanography is one of the country's largest marine science education programs, and one of the world's foremost marine research institutions.
Founded in 1961 in Narragansett, RI, GSO serves a community of scientists who are researching the causes of and solutions to such problems as acid rain, global warming, air and water pollution, oil spills, overfishing, and coastal erosion. GSO is home to the Coastal Institute, the Coastal Resources Center, Rhode Island Sea Grant, the Ocean Technology Center, and the National Sea Grant Library.
Journal
Journal of Environmental Radioactivity