Accession Number : ADA296955

Title :   Adsorbers for In-Situ Collection and At-Sea Gamma Analysis of Dissolved Thorium-234 in Seawater.

Descriptive Note : Technical rept.,

Corporate Author : WOODS HOLE OCEANOGRAPHIC INSTITUTION MA

Personal Author(s) : Hartman, M. C. ; Buesseler, K. O.

PDF Url : ADA296955

Report Date : JUL 1994

Pagination or Media Count : 20

Abstract : Two polypropylene cartridge types (Beta Pure and Hytrex II) were tested in the laboratory as adsorbers for in-situ collection of dissolved Thorium-234 (234Th) in seawater. Using a uranyl nitrate tracer, we determined that a MnO2 impregnated 3.25-inch Hytrex II cartridge with a flow rate of 8 liters/minute would collect 234Th with a greater than 60% efficiency. The smaller size and composition of the 3.25 inch Hytrex II cartridge enabled it to be pressed into a permanent 1-inch "puck" for direct gamma counting. This protocol significantly reduced the handling between collection and counting. when field tested in the Gulf of Maine as a large volume (> 500 liters) collector, the new adsorbers produced a greater than 80% collection efficiency and a dissolved 234Th concentration which was consistent with independent samples collected at the same station and depth. These adsorbers were used successfully for the in-situ collection of 234Th in large volumes of seawater during the 1992 NOAA and NSF sponsored JGOFS EqPac program, with a mean collection efficiency of 0.79 +/-9% (n = 104 cartridge pairs). jg p.3

Descriptors :   *ADSORPTION, *SEA WATER, *THORIUM, COUNTING METHODS, EFFICIENCY, MANGANESE OXIDES, POLYPROPYLENE, SAMPLING, SHIPBOARD, GAMMA RAYS, MEAN, NITRATES, CARTRIDGES, TRACER STUDIES, URANYL RADICALS.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Radiation and Nuclear Chemistry
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE