Hydrolysis, dissolved organic matter

Noblet, J.A., L.A. Smith, and I.H. Suffet (1996). Influence of natural dissolved organic matter, temperature, and mixing on the abiotic hydrolysis of triazine and organophosphate pesticides. J. Agric. Food Chem., 44 3685-3693. 

Richardot, M., Debroas, D., Thouvenot, A., Sargos, D., Berthon, J. L., and Devaux, J. (2001). Influence of cladoceran grazing activity on dissolved organic matter, enzymatic hydrolysis and bacterial growth. J. Plankton Res. 23(11), 1249-1261. 

Stone, A.T. 1989b. The effect of Dismal Swamp dissolved organic matter on the adsorption and surface-enhanced hydrolysis of monophenyl terephthalate in aluminum oxide suspensions. J, Colloid Interface Sci. 132 81-87. 

In some special cases, hydrolysis of carboxylic and carbonic acid derivatives in homogeneous solution may also be catalyzed by metal ions (see Chapter 3, this volume). The effects of dissolved organic matter on hydrolysis rates seems, however, to be of secondary importance (Macalady et al., 1989). 

Saiz-Jimenez, C. and Hermosin, B., Thermally assisted hydrolysis and methylation of dissolved organic matter in dripping water from Altamira cave, J. Anal. Appl. Pyrolysis, 49, 337-347, 1999. 

The rapid oxidation of Fe " close to the surface and in the presence of a fair supply of organic matter and dissolved Si, conditions which hinder crystallization, leads to ferrihydrite instead of goethite. The ferrihydrite is, however, often associated with goethite and it is still unknown whether the two minerals have formed simultaneously or in sequence. Simultaneous formation seems more likely for two reasons in the first place, low-temperature hydrolysis of Fe " or oxidation of Fe ", both, led to mixtures of the two oxides in different proportions if the rate of hydrolysis/oxidation was varied (Schwertmann et al. 1999 Schwertmann Cornell, 2000). Secondly, the transformation of ferrihydrite, especially in the presence of Si, appears to be extremely sluggish. 

Although hydrolysis of the triazine herbicides is temperature and pH dependent, these herbicides are considered to be hydrolytically stable under the pH and temperature conditions encountered in natural waters. However, the relatively slow hydrolysis rates in natural waters may be enhanced somewhat by the presence of dissolved organic carbon (DOC) (in the form of fulvic acids and a variety of low-molecular-weight carboxylic acids and phenols) that has been shown to catalyze the hydrolysis of several triazine herbicides. Although microbial degradation is probably the most important mechanism of dissipation of the triazine herbicides in soils, abiotic hydrolysis of these herbicides also occurs. Hydrolysis in soils is affected by the pH, organic matter (humic acid) content, and the type and content of clay in the soil. 

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