Nathan Cole-Dai, Gustavus Adolphus College

Class Year:

2024

Mentor:

Michael Gonsior, Ph.D.

Abstract:

Predominantly used in sunscreens, organic ultraviolet filters (OUVFs) are becoming water pollutants of emerging concern. Studies on the photochemistry of OUVFs are increasingly concerned with their environmental fate as opposed to the maximization of effectiveness and safety of consumer products. OUVFs have been associated with bactericide, bioaccumulation and toxicity to marine organisms, in addition to photodegradation—the symmetrical cleavage of a covalent bond under UV conditions to form multiple degradates that may experience further recombination reactions. A thorough understanding of the environmental fate of OUVFs requires knowledge of their photostability, of the kinetics of their degradation reactions, and of their photodegradates’ identities in a variety of aqueous media. In addition, natural water and wastewater components such as inorganic photocatalysts, free chlorine, chromophoric dissolved organic matter (CDOM), inorganic cations and anions, and acids and bases may influence OUVFs’ stability and the outcomes of their photochemical reactions. This comprehensive review concerns three of the most used OUVFs worldwide: octocrylene (OC), the dibenzoyl methane avobenzone (BMDBM), and the salicylate homosalate (HMS). To overall provide a sense of what has been studied on OUVFs’ fate in the hydrosphere, knowledge on the behavior of these compounds in various aqueous matrices is consolidated with knowledge on their behavior on human skin and in organic solvent. Every effort is made to classify the reaction kinetics and photoproducts of OC, BMDBM, and HMS based on previous experiments, many of which rely on the artificial irradiation of OUVF samples and the characterization of photoproducts by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS). Finally, future research objectives are outlined based on the findings of this review.

Location:

Chesapeake Biological Laboratory