Determination of transuranic and thorium isotopes in ocean water: In solution and in filterable particles

A sensitive technique for the measurement of dissolved and particulate actinide concentrations and water column distributions is described. Pu, Am, and Th isotopes are collected using large-volume, wire-mounted electrical pumping systems. Particles were removed by filtration, and actinides by absorption on MnO₂-coated filters. The very large volumes processed (up to 4000 liters) result in very sensitive and precise concentration measurements after analyses of the samples by standard radiochemical and alpha spectrometric techniques.