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The Laboratory for Environmental Analysis of RadioNuclides (LEARN)


The Laboratory for Environmental Analysis of RadioNuclides (LEARN) at Duke University seeks to gain a better understanding of the occurrence and distribution of radionuclides in the natural environment and water resources. Our laboratory is equipped with a gamma spectrometer, delayed coincidence alpha counters, and a radon monitor (RAD7) that enable us to measure a large spectrum of radionuclides in geological and environmental materials, including lead-210, uranium-235, thorium-234, radium-226, radium-228, radium-224, radium-223, radon-222, and thoron-220.

Research in LEARN focuses on three major areas:

  1. Radium isotope distribution in groundwater:
    In many aquifers, worldwide, radium and radon concentrations in local groundwater exceeds the international drinking water standards. Utilization of water with high levels of radium and radon may pose a significant health risk. Research at LEARN has found high levels of radium in groundwater from aquifers in the Negev, Israel, southern Jordan, and North Carolina, USA. In addition to providing a reliable database for the occurrence and distribution of the radium isotope quartet in these aquifers, we seek to establish geochemical models to understand better the mechanisms that control radium mobilization in groundwater resources.

  2. Radium as a geochemical tool for groundwater discharge into surface waters: Groundwater has typically high concentrations of radium as compared to surface waters. The level of radium activity in groundwater is typically associated with the salinity of groundwater. Research at LEARN aims to use these relationships to quantify groundwater subsurface discharge into lakes and river. We use the Sea of Galilee in Israel as a case study for quantifying saline groundwater discharge into fresh water lake and the adsorption of radium isotopes to the lake sediments.

  3. Proxies for high-resolution reconstruction of the sedimentary record and climate change:
    The combined use of the 137Cs, 210Pb, 226Ra, and 228Ra isotope variations measured in sediment cores from lakes and estuarine water provide important information for the rate of sedimentation and different processes that affect sediment-water interactions. Research at LEARN aims to use these variations to identify recent changes in the chemistry of lake and estuarine water that might reflect variations in hydrological patterns related to climate change.