Analytical Method for Measuring Cosmogenic ^sup 35^S in Natural Waters

Cosmogenic sulfur-35 in water as dissolved sulfate (35SO4) has successfully been used as an intrinsic hydrologic tracer in low-SO4, high-elevation basins. Its application in environmental waters containing high SO4 concentrations has been limited because only small amounts of SO4 can be analyzed usi...

Full description

Saved in:
Bibliographic Details
Published in:Analytical chemistry (Washington) 2015-06, Vol.87 (12), p.6064
Main Authors: Urióstegui, Stephanie H, Bibby, Richard K, Esser, Bradley K, Clark, Jordan F
Format: Article
Language:English
Subjects:
Analytical chemistry
Basins
Groundwater
Hydrology
Sulfide compounds
Surface water
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Cosmogenic sulfur-35 in water as dissolved sulfate (35SO4) has successfully been used as an intrinsic hydrologic tracer in low-SO4, high-elevation basins. Its application in environmental waters containing high SO4 concentrations has been limited because only small amounts of SO4 can be analyzed using current liquid scintillation counting (LSC) techniques. We present a new analytical method for analyzing large amounts of BaSO4 for 35S. We quantify efficiency gains when suspending BaSO4 precipitate in Inta-Gel Plus cocktail, purify BaSO4 precipitate to remove dissolved organic matter, mitigate interference of radium-226 and its daughter products by selection of high purity barium chloride, and optimize LSC counting parameters for 35S determination in larger masses of BaSO4. Using this improved procedure, we achieved counting efficiencies that are comparable to published LSC techniques despite a 10-fold increase in the SO4 sample load. 35SO4 was successfully measured in high SO4 surface waters and groundwaters containing low ratios of 35S activity to SO4 mass demonstrating that this new analytical method expands the analytical range of 35SO4 and broadens the utility of 35SO4 as an intrinsic tracer in hydrologic settings.
ISSN:0003-2700
1520-6882