Stable bromine isotopic composition of atmospheric CH₃Br

Abstract

Tropospheric methyl bromide (CH3Br) is the largest source of bromine to the stratosphere and plays an important role in ozone depletion. Here, the first stable bromine isotope composition (%26dgr%3B81Br) of atmospheric CH3Br is presented. The %26dgr%3B81Br of higher concentration Stockholm samples and free air subarctic Abisko samples suggest a source/background value of %26minus%3B0.04%26plusmn%3B0.28%26permil%3B ranging up to +1.75%26plusmn%3B0.12%26permil%3B. The Stockholm %26dgr%3B81Br versus concentration relationship corresponds to an apparent isotope enrichment factor of %26minus%3B4.7%26plusmn%3B3.7%26permil%3B, representing the combined reaction sink. This study demonstrates the scientific potential of atmospheric %26dgr%3B81Br measurements, which in the future may be combined with other isotope systems in a top-down inverse approach to further understand key source and sink processes of methyl bromide

Genesis of salinized groundwater in Quaternary aquifer system of coastal plain, Laizhou Bay, China: Geochemical evidences, especially from bromine stable isotope

“…10), implying that agriculture activities could also have little influence on Br isotope signatures in brackish water. However, it is worth noting that sample 1222 and 1223 show a decrease of the d 81 Br values, probably toward the anthropogenic CH 3 Br mean value of +0.12 ± 0.9‰ (Horst et al, 2013).…”

“…However, based on the same principle, the authors believe that the same atmospheric process would also result in Br isotope fractionation, and make the recharge water more enriched in 81 Br. Previous results (Eggenkamp, 2014;Gwynne et al, 2013;Horst et al, 2013) indicated that bromine is enriched from selective atmospheric processes (e.g. photolysis of bromomethane) causing fractionation in marine aerosols during transport, and exhibited the enrichment of 81 Br in groundwater in the recharge area.…”

Isotope Fractionation Processes of Selected Elements

“…CH 3 Br may originate from natural and anthropogenic sources. Horst et al (2013) determined the Br isotope composition of methyl bromide at two locations in Sweden. Subarctic samples in northern Sweden were more negative than samples in the Stockholm area.…”

Isotopic Characterization (2H, 13C, 37Cl, 81Br) of the Abiotic Sinks of Methyl Bromide and Methyl Chloride in Water and Implications for Future Studies.

“…Apart from carbon isotope analysis, hydrogen isotope 10 measurements have been demonstrated for CH3Cl (Nadalig et al, 2013;Keppler et al, 2018;Jaeger et al, 2018). For CH3Br bromine isotope analysis was presented in two studies (Horst et al, 2013;Horst et al, 2014).…”