Solubilities of Pesticide Chemicals in Water Part I: Environmental Physical Chemistry

Abstract

In 1968 Gunther, Westlake, and Jaglan compiled and published data on the water solubility of 738 pesticide chemicals. That pioneering review noted that there were “glaring inconsistencies and lamentable gaps in the literature commonly available to research workers and others interested in even approximate solubility data.” For 63% of the chemicals either no data were available or the information was of a purely qualitative nature, for example, a statement to the effect that the chemical was “relatively insoluble” (Gunther et al. 1968). In the two decades since that review there has been considerable improvement in the quantity and quality of reported data and a deeper understanding has emerged of the relationships between solubility and other physical-chemical properties, notably octanol-water partition coefficient K _ow (Chiou et al. 1977, 1982, Mackay et al. 1980, Miller et al. 1985) and other environmentally relevant partition coefficients such as those between air and water (Mackay and Shiu 1981), and water and organic carbon (Karickhoff et al. 1979) or lipid phases (Kenaga 1980a,b, Briggs 1981, Mackay 1982, Chiou 1985, Seiber 1987). Further, the role that physical-chemical properties play in determining pesticide fate in the environment is now much clearer (Biggar and Seiber 1987). Methods for assessing or predicting chemical behavior have been improved by exploiting the greater availability of computers and computer models. Such assessments routinely require information on water solubility, not only for agricultural chemicals but also for chemicals in general commercial use.