Dissolved organic carbon transformations

The most common partition coefficient encountered in environmental work (Sect. 2.1.4) is the octanol water partition coefficient (K0VI) and the solid phase carbon-water partition coefficient (Koc). A partition coefficient for dissolved organic matter-water (i. e., Kd ()M) or dissolved organic carbon-water (i. e., Kd oc) occasionally appears in the literature. In the case of PCBs, Boyd and Sun [378] defined a partition coefficient for residual transformer oil and water as Kd oil, while Sun and Boyd [379] defined a coefficient for PCB dielectric fluid-water as Kd pen-These authors [378,379] identified a total partition coefficient that com-... 

Environmental releases of PCBs often accompany releases of carriers from utility equipment. An example would be mineral oil released from oil filled transformers. When PCBs are present in a mineral oil-PCB mixture the aqueous solubility of the PCBs is reduced significantly. Two factors play a role in this reduction partitioning of the lipophilic (oil-loving) PCBs into the oil phase, and the reduced interaction of the PCBs with precipitation or groundwater caused by the hydrophobic nature of the oil matrix. Interpretation of aqueous PCB concentrations in the field must consider the presence of dissolved organic carbon (DOC) [382,386,397,403]. 

Unlike the transformation processes that reduce the total amount of triazine present in soil, retention only decreases the amount available for weed control, microbial transformations, or transport. The amount retained or sorbed by soil can range from 0% to 100% of the amount applied, but sorption on silt loam, loam, or clay loam soils typically ranges from 50% to 80%. Triazine retention in soil is influenced primarily by organic carbon content, soil clay content and type, and soil pH. Other factors influencing retention include the amount of triazine applied, the amount of dissolved organic carbon (DOC) in soil solution, soil water content, and triazine to soil contact time (aging). 

Engelhaupt, E., Bianchi, T.S., Wetzel, R.G, and Tarr, M.A. (2002) Photochemical transformations and bacterial utilization of high-molecular-weight dissolved organic carbon in southern Louisiana tidal stream (Bayou Trepagnier). Biogeochemistry 62, 39-58. 

Chasar L. S., Chanton J. P., Glaser P. H., Siegel D. I., and Rivers J. S. (2000b) Radiocarbon and stable carbon isotopic evidence for transport and transformation of dissolved organic carbon, dissolved inorganic carbon, and CH4 in a northern Minnesota peatland. Global Biogeochem. Cycles 14, 1095-1108. 

In conclusion, we have to outline the limits of respiratory methods. Indeed, in the metabolic reaction, polymer carbon is used by microorganisms to produce not only C02, but also oligomers and new biomass. Thus, a single measurement of C02 (or, what is worse, consumed 02) is not sufficient to clearly indicate the amount of transformed polymer. Dissolved organic carbon (DOC) is sometimes measured at the end of the test and indicates the amount of oligomer remaining in the medium. This procedure should be obligatory in order to make the balance of carbon, and to check if there are no unexpected losses. 

Activated Carbon Atomic Force Microscopy Aquanc Organic Matter Agricultural Research Management Council of Australia and New Zealand Attenuated Total Reflection Fourier Transformation Infrared Spectroscopy Biodegradable Dissolved Organic Carbon Cellulose Acetate... 

Transformation of reactive organic substances will result in variations of redox potential, pH-values, as well as concentrations of inorganic ions and dissolved organic carbon the latter two components may enhance complexation of metals. Regarding the subsequent consideration, acid-producing potentials derived from oxidation of sulphides and organic matter are of prime importance. 

This process combines the use of biological activated carbon with adsorption. The biodegradable organic matter, or biodegradable dissolved organic carbon, which enters with the raw water is transformed into carbon dioxide and biomass by heterotrophic bacteria fixed on the carbon. The biomass is then partially consumed by protozoa. An equilibrium is reached among the inflow of food, bacteria, protozoa and algae. This equilibrium must be carefully controlled in order to assure the... 

Ma, X.D. and Green, S.A. (2004). Photochemical transformation of dissolved organic carbon in Lake Superior - An in-situ experiment. J. Great Lakes Res., 30,97-112. 

In many freshwater aquatic systems, dissolved organic material (DOM) represents a major pool of organic material. Processes that produce, consume, and transform DOM are important in the overall cycling of carbon, energy, and nutrients in these aquatic ecosystems. Current research has... 

Transformations and Cycling of Dissolved and Particulate Organic Carbon... 

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