Halogen Radicals in Aquatic Systems

Halogen Radicals & the Roles of Halides in Photochemistry

Environmental Science & Technology

Cover art featuring Parker et al. 2016, selected as Environmental Science & Technology’s Best Science Paper of 2016 (link).

Seawater Photochemistry

Along with sodium, halides (i.e. chloride, Cl¯, and bromide, Br¯) are the dominant constituents of sea salt. Despite the importance of sunlight photochemistry in halide-containing waters, the role of halides in photochemical reactions was previously not well understood. Dr. Parker’s work demonstrated that halides have an important role in seawater photochemistry, particularly through the photogeneration of halogen radical oxidants (e.g. Reactive Halogen Species, RHS). Ongoing work seeks to understand the implications of these seawater-specific photooxidants for important marine biogeochemical processes, such as the aqueous transformation of dimethyl sulfide (DMS), a precursor to cloud condensation nuclei.


Drinking Water  Treatment

New projects underway seek to investigate halogen radicals during advanced water treatment processes. Contact Dr. Parker for more information!



Related Publications

Parker KM, Reichwaldt E, Ghadouani A, Mitch WA. Halogen Radicals Promote the Photodegradation of Microcystins in Estuarine Systems.Environmental Science & Technology, 2016, 50 (16), 8505-8513. (Full text)

  • Selected as Environmental Science & Technology’s Best Science Paper of 2016 (link).

Parker KM, Mitch WA. Halogen radicals contribute to photooxidation in coastal and estuarine waters. Proceedings of the National Academy of Sciences USA, 2016, 113 (21), 5868-5873. (Full text)

  • News Feature: Stanford News, May 9, 2016 (link)

Parker KM, Pignatello JJ, Mitch WA. Influence of ionic strength on triplet-state natural organic matter loss by energy transfer and electron transfer pathways. Environmental Science & Technology, 2013, 47 (19), 10987-10994. (Full text)