Marine versus Continental Sources of Iodine and Selenium in Rainfall at Two European High-Altitude Locations.

Elke Suess,Franziska Aemisegger,Lenny H E Winkel,Heini Wernli,Jeroen E Sonke,Michael Sprenger

doi:10.1021/acs.est.8b05533

Abstract

The essential elements selenium (Se) and iodine (I) are often present in low levels in terrestrial diets, leading to potential deficiencies. Marine I and Se emissions and subsequent atmospheric wet deposition has been suggested to be an important source of I and Se to soils and terrestrial food chains. However, the contribution of recycled moisture of continental origin to I and Se to precipitation has never been analyzed. Here we report concentrations and speciation of I and Se, as well as of bromine (Br), sulfur (S), and DOC-δ13C signatures for weekly collected precipitation samples (in the period of April 2015 to September 2016) at two high altitude sites, i.e., Jungfraujoch (JFJ; Switzerland) and Pic du Midi (PDM; France). Analysis of precipitation chemistry and moisture sources indicate combined marine and continental sources of precipitation and Se, I, Br, and S at both sites. At JFJ, concentrations of I and Se were highest when continental moisture sources were dominant, indicating important terrestrial sources for these elements. Furthermore, correlations between investigated elements and DOC-δ13C, particularly when continental moisture source contributions were high, indicate a link between these elements and the source of dissolved organic matter, especially for I (JFJ and PDM) and Se (JFJ).

Highlights

INTRODUCTION Importance ofIodine (I) and Selenium (Se) in Human Health
Many trace elements are essential for human health, low dietary intake can cause micronutrient deficiencies that have been estimated to affect over 3 billion people around the globe.[1]
Two such essential trace elements, which are often deficient in human diets are iodine (I) and selenium (Se).[2,3]

Summary

Introduction

INTRODUCTION Importance ofIodine (I) and Selenium (Se) in Human Health. Many trace elements are essential for human health, low dietary intake can cause micronutrient deficiencies that have been estimated to affect over 3 billion people around the globe.[1]. Despite the fact that the body requires relatively small amounts of I, deficiency disorders caused by inadequate intakes are widespread.[2,5] Se is an essential element for humans as it is needed in a small set of selenoproteins that serve redox functions.[6−9] Sources of both I and Se in the human diet are food crops (especially for Se), meat, dairy products, sea food, and food additives, especially for I in the form of iodized salt.[5,10]

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