Determination of Bromide by Ion Chromatography in NADP/NTN Samples and Background Levels in Central Analytical Laboratory Weekly Blank Samples

Lee Green, Tracy Dombek, and Christopher Lehmann
Central Analytical Laboratory
National Atmospheric Deposition Program
Illinois State Water Survey, Institute of Natural Resource Sustainability
University of Illinois at Urbana-Champaign
Champaign, IL 61820;

Bromide is released into the environment via natural and anthropogenic processes. Brominated flame retardants are used in the production of polymers because they increase the fire resistance of a wide variety of products produced from polymers. Methyl bromide is a fumigant applied before plant growth as well as post harvest for a variety of fruits and vegetables. Methyl bromide is classified as an ozone-depleting substance, and its use is strictly regulated and monitored by the U.S EPA. Users must meet criteria set by the EPA for critical use before purchasing and applying methyl bromide. Although there are regulations in place, there is a concern about the amount of bromide present in the atmosphere.

Bromide concentrations have been measured in all NTN and AIRMoN samples since June of 2009. Additional funding was provided by the U.S. Geological Survey to evaluate bromide concentrations in NTN archive samples. Archive samples from 2001 and 2002 were selected based upon geographical locations and agricultural activities in those areas. Spatial and temporal trends are evaluated and presented from the data obtained for 2001-2002 and 2009-2010.

The Central Analytical Laboratory (CAL) has continued to measure bromide in blank samples, which are monitored weekly, to evaluate the cleanliness of buckets, lids, bottles and bags used to collect, transport, and contain NADP/NTN samples. Detection limits and background levels will be updated based on results obtained through 2009 and 2010. The blank data are compared to typical concentrations observed in NTN samples to evaluate the ability of the CAL to measure long-term bromide ion trends in precipitation.