Natural Organic Matter

Abstract

Abstract This chapter focuses on the composition and behavior of natural organic matter (NOM) in aquatic systems. The chemical, ecological, and engineering significance of these substances is described, along with the terminology associated with NOM and its dissolved fraction (DOM). Emphasis is given to DOM and its colored component, known as CDOM, which is closely related to aquatic humic matter (AHM)—fulvic and humic acids. CDOM represents the bulk of DOM in many surface waters. The chapter describes methods to isolate and chemically characterize DOM and CDOM (AHM) by NMR, high-resolution mass spectrometry and other modern methods. A historical perspective illustrates changing views on the chemical structure of AHM over time, and the chemical composition of DOM associated with major types of natural and anthropogenic water bodies is described. The spectral, redox, acid-base, and metal-binding properties of DOM are explained, and current metal-binding models, WHAM and NICA-Donnan, are described.