Humic substances are the predominant form of natural organic matter (NOM) in soil and water and comprise the major pools of biologically refractory organic carbon and nitrogen in the biosphere. Humic substances play a role in almost all geochemical processes affecting soil and water. Knowledge of the formation and mineralization pathways of soil and aquatic humic substances is therefore critical to an understanding of the biogeochemical cycles of carbon and nitrogen, and climate change. Humic substances act as electron donor-acceptor systems and thus participate in oxidation –reduction processes with transition metal ions and biological systems in soil and water environments. Chlorination and chloramination of NOM during water treatment [...]