Aromatic pollutants such as polycyclic aromatic hydrocarbons (PAHs) are common contaminants in natural waters. Their photolysis in the environment often leads to the formation of toxic products that can harm aquatic life. We have measured photolysis kinetics of the PAHs anthracene and pyrene in solutions designed to mimic various environments, such as sea water, fresh water, and sea surface microlayers (SSMs). Halide salts and sulfate, which are major components of sea water and sea spray aerosols, suppressed pyrene photolysis but enhanced anthracene photolysis kinetics, while the presence of organic matter – whether internally mixed in the sample or in the form of a distinct layer, such as is observed with SSMs – suppressed both anthracene and pyrene photolysis kinetics. This suppressing effect was observed even for organic species that do not absorb sunlight; we determined that this was primarily due to changes in polarity. Our results suggest that the fate of PAHs in natural waters and aqueous aerosols could be significantly different than those predicted by kinetics measured in the absence of solutes.<br/>

Effects of the local environment on photolysis kinetics of aromatic pollutants in natural waters

251st National Meeting (2016)

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