Method for characterization of inert organic carbon in urbic anthrosols

Organic matter in Urbic Anthrosols often contains chemically and biological ly inert organic carbon. This material, called black carbon (BC), originate s from municipal wastes, coal-mine deposits and/or fly ash. This black carb on needs to be differentiated from the other soil organic substances becaus e of its very different physical and chemical nature. In this paper, we pro pose a new method for determining BC, integrated into the humic fractionati on procedure. The remaining organic carbon in the soil residue left after l ipid extraction, alkaline extraction [0.5 M sodium hydroxide (NaOH)], and f urther oxidation with 30% hydrogen peroxide (H2O2) is defined as inert orga nic carbon or BC. The common fractions of soil organic matter, such as lipi ds, fulvic and humic acids, and humins are thus supplemented with a new fra ction, BC. According to our results by C-13-NMR spectroscopy, this fraction consists mainly of polyaromatic hydrocarbons with few functional groups.