Florescence Responses of Dissolved Organic Matter (DOM) Fractions to Typical Urban Source Pollution in Natural Water

The entire dissolved organic matter(DOM) and its fractions in natural water were investigated by resin fractionation and 3D fluorescence techniques to reveal their mechanisms and response characteristics to typical urban source pollution.The first stage fractionation result of DOM showed that hydrophobic base and neutral fraction(HoBN) and weakly hydrophobic acid(WHoA) had some degree of response to urban source pollution,and the amount of dissolved organic carbon(DOC) and relative proportions of both fractions increased dramatically in urban-polluted water.Further results of the 3D-fluorescence characteristics of each fraction in DOM showed that hydrophobic acid(HoA),HoBN and WHoA all had favorable responses to urban source pollution in natural water.The fluorescence response and characteristics of HoA and HoBN in polluted water were relatively prominent and abundant,and were mainly emitted by protein-like matter with UV absorbance.The WHoA varied especially strongly when it was transported from non-polluted source areas,where it was fulvic-like matter with π-structure,to urban water,where it almost disappeared and had a sharply depressed fluorescence response.