title: Simple Method for High-Sensitivity Determination of Cosmogenic35S in Snow and Water Samples Collected from Remote Regions.
abstract: Cosmogenic35S is useful in understanding a wide variety of chemical and physical processes in the atmosphere, the hydrosphere, and the cryosphere. The 87.4-day half-life and the ubiquity of sulfur in natural environments renders it an ideal tracer of many phenomena. Measurements of35S in snow and water samples are scarce as existing analytical methods require a large volume of sample (>20 L) due to their high analytical activity background and low counting efficiency. Here, we present a new set of snow/water sample collecting and handling procedures for high-sensitivity determination of cosmogenic35S using a low-level liquid scintillation spectrometer. Laboratory experiments using diluted35S standards (with activities of <5 disintegrations per minute) showed a35S recovery percentage of ∼95%, demonstrating a relatively small deviation from the true value. Using this method, we successfully measured35S in ∼1 L of fresh snow sample collected from a glacier on the Tibetan Plateau to be 47 ± 7 mBq/L. On the basis of35S activities in 9 natural samples measured in this study, a first proof-of-concept approximation for age determinations and source attributions was presented. This new method will provide a powerful tool in studying35S in small volumes of snow and water samples, especially those from remote but climatically important regions such as the polar regions and the Tibetan Plateau and Himalayas. The measurements are particularly important as the radioactive sulfur provides an actual clock of glacial melting processes. With the growing rate of glacial loss, the need for measurements from remote locations becomes all the more important.
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego , La Jolla, California 92093, United States.
authors.forename: Mang
authors.identifier: 0000-0001-8904-7697
authors.initials: M
authors.lastname: Lin
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego , La Jolla, California 92093, United States.|State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS) , Lanzhou 730000, China.|University of CAS , Beijing 100049, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS) , Lanzhou 730000, China.|CAS Center for Excellence in Tibetan Plateau Earth Sciences , Beijing 100101, China.|University of CAS , Beijing 100049, China.
authors.forename: Shichang
authors.initials: S
authors.lastname: Kang
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego , La Jolla, California 92093, United States.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Thiemens