Slow-stirring method, partition coefficients

De Bruijn, J., Busser, G., Seinen, W., Hermens, J. (1989) Determination of octanol/water partition coefficient for hydrophobic organic chemicals with the slow-stirring method. Environ. Toxicol. Chem. 8, 499-512. 

Mass exchange between a non-aqueous-phase liquid (NAPL) such as diesel fuel and water can be studied with the so-called slow stirring method (SSM). The SSM was designed to determine solubilities and octanol-water partition coefficients of organic compounds such as petroleum hydrocarbons. The kinetics of the exchange process also yield valuable information on the exchange between ground-water and a NAPL spilled into an aquifer. 

Fisk, A T., Bosenberg, B., Cymbalisty, C.D, Stem, G.A., Muir, D.C.G. (1999) Octanol/water partition coefficients of toxaphene congeners determined by the slow-stirring method. Chemosphere 39, 2549-2562 Fisk, AT., Norstrom, R.J., Cymbalisty, C.D, Muir, D.C.G. (1998) Dietary accumulation and depuration of hydrophobic oiganochlo-rines bioaccumulation parameters and their relationship with the octanol/water partition coefficient. Environ. Toxicol. Chem. 17, 951-961. 

Fisk, A.T., Bosenberg, B., Cymbalisty, C.D., Stem, G.A., Muir, D.C.G. (1999) Octanol/water partition coefficients of toxaphene congeners determined by the slow-stirring method. Chemophere 39, 2549-2562. 

VII) The best or right n-octanol/water partition coefficients which were experimentally determined e.g. by the slow-stirring method or the HPLC method (in agreement with the OECD guideline) were used for establishing the QSAR. 

Water solubility determined by the generator column method by van Haelst et al. [244]. n-Octanol/water partition coefficients determined by Van Haelst et al. using the slow stirring method [245]. 

The octanol-water partition coefficient for surfactants can not be determined using the shake-flask or slow stirring method because of the formation of emulsions. In addition, the surfactant molecules will exist in the water phase almost exclusively as ions, whereas they will have to pair with a counter-ion in order to be dissolved in octanol. Therefore, experimental determination of K w does not characterize the partition of ionic surfactants (Tolls, 1998). On the other hand, it has been shown that the bioconcentration of anionic and non-ionic surfactants increases with increasing lipophilicity (Tolls, 1998). Tolls (1998) showed that for some surfactants, an estimated log Kow value using LOGKOW could represent the bioaccumulation potential however, for other surfactants some correction to the estimated log Kow value using the method of Roberts (1989) was required. These results illustrate that the quality of the relationship between log Kow estimates and bioconcentration depends on the class and specific type of surfactants involved. Therefore, the classification of the bioconcentration potential based on log Kow values should be used with caution. 

OECD draft Test Guideline, 1998. Partition Coefficient n-OctanoFWater Pow Slow-stirring method for highly hydrophobic chemicals. Draft proposal for an OECD Guideline for Testing of Chemicals... 

OECD Guidelines for the Testing of Chemicals 123, Partition Coefficient (1-Octanol/Water) Slow-Stirring Method, Organisation for Economic Co-operation and Development, Paris, France, 2006. 

Log ATow is the logio octanol-water partition coefficient. Included are the mean, standard deviation (sd), and standard error of the mean (sem) for all data. Data from 1, Radding et al. (1976) 2, Leo et al. (1971) 3, Karickhoff et al. (1979) 4, de Bruijn et al. (1989) 5, Hansch and Leo (1979) 6, Konasewich et al. (1982) 7, Krishnamurthy and Wasik (1978) 8, Mackay et al. (1980) 9, Means et al. (1980) 10, Miller et al. (1985) 11, Mills et al. (1982) 12, U.S. EPA Athens, slow stir method 13, Bruggeman et al. (1982) 14, Hammers et al. (1982) 15, De Kock and Lord (1987) 16, D Amboise and Hanai (1982) 17, early-release prototype version of the SPARC model, Karickhoff et al. (1991). Bold indicates mean of many values from this citation MW is molecular weight in daltons. No distinction was made between measured and calculated AT s. Most AowS for a compound are unique however, there is the possibility that some entries occur in two or more citations. 

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