The effects of climate change and the resulting global rise of sea levels has caused coastal freshwater wetlands, such as those found in the Southeastern United States, to be threatened by saltwater intrusion. This results in a high influx of Cl- and Br- into coastal estuaries, and this alteration of seawater chemical composition significantly changes the ecosystem, and importantly, the formation and reactivity of natural organic matter in salt-impacted wetlands. As more halides come into contact with labile natural organic matter on the coast, the system responds to this change by elevated production of organohalogens, many of which are considered to be a toxic class of compounds and persistent in the environment. We use synchrotron X-ray spectroscopy to characterize bromine speciation in salt-impacted wetland soil samples from the Winyah Bay in South Carolina and in freshwater wetland samples exposed to bromine under laboratory conditions. Organobromine is shown to be produced at levels of 80-90%, relative to inorganic bromine, under seawater like conditions[SM1] . In addition, we show that elevated levels of seawater intrusion in soil systems has impacted the organochlorine that is originally part of natural organic matter. Previous studies have indicated increased chloromethane emissions in salt-impacted wetlands, and this may have been caused by the halogenation reactions in these coastal wetlands.

Effect of sea level rise on the production of organohalogens in coastal wetlands

253rd National Meeting (2017)

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