Natural photochemical nanoreactors in aquatic systems

The acceleration of photochemical reactions by humic substances in natural waters has been known for decades.  The prevailing model is that sunlight-excited organic matter is the source of a family of reactive species, such as singlet oxygen and hydrated electron.  The reactive species are then free to diffuse through the aqueous phase reacting with substrates in their path.  There have been some reports that indicate that instead of occurring in the aqueous phase, some of these photochemical reactions are occurring inside the supramolecular structure of the natural organic matter itself.  Data supporting this view of natural organic matter as a natural nano-scale photoreactor will be presented and its consequences for hydrophobic pollutant (H) degradation, pathogen inactivation, and carbon cycling will be discussed.