Deposition of atmospheric selenium to the northern Greenland ice sheet during the 1900-1970 AD

Abstract

Selenium is one of the trace elements which are essential for human and animals health. Previously, numbers of researches have been carried out with various environmental samples, and it has been known that atmospheric transport of selenium plays important role in its bio-geochemical cycle (Wen and Carignan, 2007). Most of previous researches focused on spatial distribution and/or changes over short period less than one year (Ellis et al., 1993; Kagawa et al., 2003; Ranville et al., 2010). Only one record showing long-term changes in atmospheric selenium was reported 40 years ago from Greenland ice core (Weiss et al., 1971). This study, however, did not follow clean protocols essential for analysis for trace metals in ice core, and thus the reliability of data was not confirmed. In This research, past changes in atmospheric selenium during 1900-1970s are recovered from the Greenland NEEM ice core. The selenium concentrations increases from 1900 to 1940, and then decreased until 1970s. The largest natural and anthropogenic sources for atmospheric selenium are marine bioactivity and coal combustion, respectively. The selenium record of Greenland NEEM ice core is rather similar to that of chlorophyll concentration in North Atlantic, while global coal consumption record did not show decrease (Boyce et al., 2010; Roser, 2015). Therefore, it can be inferred that the input of atmospheric selenium during the 20th century was controlled by the marine bio-activity in North Atlantic.