First study on ²³⁶ U in the Northeast Pacific Ocean using a new target preparation procedure for AMS measurements

Author(s)

R. Eigl, P. Steier, S. R. Winkler, K. Sakata, A. Sakaguchi

Abstract

We succeeded in obtaining the depth profile of

²³⁶ U for a sampling station in the Northeast Pacific Ocean using only one litre of seawater sample from each depth. For this purpose, a new procedure was developed that allowed for the preparation of accelerator mass spectrometry targets for trace uranium using only 100 μg of iron carrier material. The

²³⁶ U concentrations in water samples from the Northeast Pacific Ocean showed large variations from (9.26 ± 0.42) × 10

⁶ atoms/kg at 60 m depth to (0.08 ± 0.02) × 10

⁶ atoms/kg at a depth of 3000 m. The high

²³⁶ U concentrations in surface water reflect the input of

²³⁶ U by global and local fallout from nuclear weapons tests. The low

²³⁶ U concentrations in seawater from 1500 m and below are an indicator for the low vertical diffusion of surface water to deeper layers in the North Pacific Ocean. The total inventory of

²³⁶ U on the water column was (8.35 ± 0.23) × 10

¹² atoms/m

² , which is lower compared to those of other ocean regions solely affected by global fallout on comparable latitudes. This study represents the first dataset for

²³⁶ U in the Pacific Ocean and shows the possibility of downsizing sample volumes which may help in future applications of

²³⁶ U as tracer for large ocean areas.

Organisation(s)

Isotope Physics

External organisation(s)

Hiroshima University, National Research Foundation, University of Tsukuba

Journal

Journal of Environmental Radioactivity

Volume

162-163

Pages

244-250

No. of pages

7

ISSN

0265-931X

DOI

https://doi.org/10.1016/j.jenvrad.2016.05.025

Publication date

10-2016

Peer reviewed

Yes

Austrian Fields of Science 2012

103013 Ion physics, 103037 Environmental physics

Keywords

ASJC Scopus subject areas

Pollution, Waste Management and Disposal, Health, Toxicology and Mutagenesis, Environmental Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/1e3a5e0c-e429-4605-bb39-8a8d585fec84