Photochemical Degradation Studies

Photochemical Degradation of Organic UV Filter Chemicals in Surface Waters

Organic ultraviolet filter chemicals (UVFCs) detected in surface waters and biota are listed active ingredients in numerous personal care products. The fate of UVFCs in the aquatic environment will affect the relative potential for bioaccumulation and toxicity, and little is currently known about potential elimination processes. This research project considers the breakdown of FDA-approved UVFCs in model and natural surface waters under simulated and natural sunlight. Results from these experiments indicate the relative importance of direct and indirect photolysis and the effects of seasonal variability. Our goal is to identify photochemical degradation products and to measure the contribution of photochemical degradation to the environmental half-lives of UVFCs in surface waters.

OMC degradation scheme

The direct photolysis of trans-OMC results in photoisomerization (formation of cis-OMC) followed by the degradation/transformation of both OMC isomers to form smaller products and cyclodimers (MacManus-Spencer, L. A.; Tse, M. L.; Klein, J. L.; Kracunas, A. E. Aqueous photolysis of the organic ultraviolet filter chemical octyl methoxycinnamate. Environmental Science and Technology 2011, 45, 3931-3937).