Rapid mapping of anthropogenic radionuclides, metals, and organic compounds in surficial marine sediments

Abstract

The Center for Applied Isotope Studies has developed a rapid survey system that enables continuous collection, analysis, and near real time mapping of surficial bottom sediments in aquatic environments while the survey vessel is underway. The system is used to measure and map radiometric parameters of surficial sediments by continuous in situ detection of gamma activities, and to determine and map elemental concentrations of sediments using non-destructive X-ray fluorescence (XRF) analysis of sediment wafers processed from samples collected at the sediment/water interface. The CAIS is now expanding system capabilities by incorporating a field-portable gas chromatograph/mass spectrometer (GC/MS) into the sample processing line of the existing survey system, enabling in situ measurement of selected organic compound constituents in surficial sediment samples. To date, a sonication method using methylene chloride has been developed for sample extraction, and satisfactory detection levels have been obtained in the laboratory. A thermal desorption method is being developed for shipboard applications and near real time mapping of organic constituents of surface sediments.