Document Type

Dissertation - Open Access

Award Date

2024

Degree Name

Doctor of Philosophy (PhD)

Department / School

Chemistry and Biochemistry

First Advisor

Jihong Cole-Dai

Keywords

Greenland ice core, Maunder Minimum, perchlorate, solar radiation, sunspot number

Abstract

Perchlorate, which derives from both anthropogenic and natural sources in the current environment, poses a substantial health hazard to humans as it competes with iodine uptake in the thyroid gland. Consequently, there has been considerable concern about minimizing human exposure to environmental perchlorate by restricting its release from man-made sources. However, the absence of a clear understanding regarding the respective contributions of man-made and natural sources has hindered widespread regulation efforts. A 300-year (1700–2007) Summit, Greenland ice core record from a previous study showed relatively stable perchlorate concentrations in Greenland snow prior to 1980, with some elevated perchlorate levels associated with large volcanic eruptions that inject a substantial amount of SO2 and HCl gases into the stratosphere. The present 400-year perchlorate record from Summit, Greenland ice cores shows that the 1601–1700 time period is an exception to the stable pre-industrial perchlorate level. The average perchlorate concentration (standard deviation) from 1601 to 1700 (2.1 ± 1.5 ng kg-1) is nearly twice (p-value

Library of Congress Subject Headings

Perchlorates -- Environmental aspects.
Ice cores -- Analysis.
Solar radiation.
Sunspots.

Publisher

South Dakota State University

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Rights Statement

In Copyright