Photochemical Implications of Changes in the Spectral Properties of Chromophoric Dissolved Organic Matter: A Model Assessment for Surface Waters.

Chromophoric dissolved organic matter (CDOM) is the main sunlight absorber in surface waters and a very important photosensitiser towards the generation of photochemically produced reactive intermediates (PPRIs), which take part in pollutant degradation. The absorption spectrum of CDOM ((λ), unitless) can be described by an exponential function that decays with increasing wavelength: (λ) = 100 DOC e, where [m] is water depth, DOC [mg L] is dissolved organic carbon, [L mg cm] is a pre-exponential factor, and [nm] is the spectral slope. Sunlight absorption by CDOM is higher when and DOC are higher and is lower, and vice versa.