Dissolved organic matter light absorption

Natural substances (dissolved organic matter, DOM) also contribute to light absorption, and a, is used to account for light attenuation by DOM in natural water. Total light absorption in a natural water follows the relation in Equation (5) ... 

Harmful substances may be present in water in either undissolved or dissolved form. Some organic compounds in water can absorb the UV light in a wavelength range of 254-280 nm. Just as turbidity detection is used to measure the total solids content, UV absorption detection at a wavelength of 254 nm can be employed to measure the total content of dissolved organic matter. The typical absorbance values at 254 nm for some important types of waters are listed in Table 1. 

A fraction of the organic compounds present in dissolved organic matter absorbs light and a subfraction of these also fluoresce (Figure 8.1). For several decades, the optical (absorption and fluorescence) properties of DOM have been used to study both the distribution of DOM and its characteristics in aquatic environments. The major advantage of the approach is that it requires very small sample volumes and minimal preparation before... 

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