Dissolved humic material, effect

Gauthier T, Seitz W, Grant C (1987) Effects of structural and compositional variations of dissolved humic materials on pyrene Koc values. Environ Sci Technol 21 243-248... 

McCarthy, J.F., Jimenez, B.D., Barbee, T. (1985) Effect of dissolved humic material on accumulation of polycyclic aromatic hydrocarbons structure-activity relationships. Aqua. Toxicol. 7, 15-24. 

Schlautman, M.A., Morgan, JJ. (1993a) Effects of aqueous chemistry on the binding of polycyclic aromatic hydrocarbons by dissolved humic materials. Environ. Sci. Technol. 27, 961-969. 

If released to water, 1,3-DNB and 1,3,5-TNB may be subject to direct photolysis when exposed to sunlight because both compounds can absorb light at wavelengths greater than 290 nm (ERA 1976 Mill and Mabey 1985). However, no data were located regarding the photolysis of 1,3,5-TNB in water. The photolytic half-life of 1,3-DNB in pure water was calculated to be 23 days (Simmons and Zepp 1986). A three-to four-fold increase in the rate of photoreaction of 1,3-DNB was observed in ambient waters containing natural humic substances or in distilled water containing dissolved humic materials compared to reaction without humic substances (Simmons and Zepp 1986). This enhancement of the reaction rate has been attributed to catalysis of the photoreaction by photosensitization effects of humic substances. 

Cotner, J. B., and R. T. Heath. 1990. Iron redox effects on photosensitive phosphorus release from dissolved humic materials. Limnology and Oceanography 35 1175-1181. 

Stewart A. J., and R. G. Wetzel. 1981. Dissolved humic materials Photodegradation, sediment effects, and reactivity with phosphate and calcium carbonate precipitation. Archiv fur Hydrobiologie 92 265-286. 

Ortego, L.S. and Benson, W.H. (1992) Effects of dissolved humic material on the toxicity of selected pyrethroid insecticides, Environmental Toxicology and Chemistry 11 (2), 261-265. 

Calculations which consider binding of sorbing solutes to dissolved humic matter show that the previously reported inverse relationship between effect of sediment concentration and sorption equilibrium can be accounted for by desorption of humic material followed by binding to the DOC (46, 48). 

Dissolved humic and fulvic acids can be isolated from the total DOC pool by adsorption onto resins as discussed by Aiken in Chapter 14 of this book. Muenster (1982) found that 77-86% of the DOC (measured by UV absorbance and organic carbon) adsorbed onto XAD resin at pH values of 2.0-3.0. Adsorption onto PVP resin was slightly less effective (70-76% at pH values of 2.0-3.0). These differences in adsorption efficiency may be explained by organic material other than humic substances being retained on these resins. 

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