Photochemistry in the hydrosphere and soil

Most of the Earth s surface is covered by water, which forms oceans, seas, rivers, estuaries, lakes, ponds, streams, pools, and puddles. The water basins contain various chemicals of both natural and anthropogenic origin. In the aquatic medium, more 

The maximum depth for the light level corresponding to 0.1 % of incident light for the wavelength of interest involved in a given photochemical reaction in surface or marine water is called the photochemical zone . Typical values of absorption coefficients for surface and marine waters at 400 nm correspond to a depth of 6-30 m, whereas for shorter wavelengths the depth is much smaller. Thereby, photochemical reactions in water basins are confined to their top layers [10]. 

There are three typical classes of compounds, for which photochemistry plays a crucial role in surface and marine waters nitrate ions, humic substances, and transition metal ions. 

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