Stability of chlorpyrifos for termiticidal control in six Australian soils.

Chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate] is the most widely used soil-applied termiticide in Australia. It is relatively stable, has low water solubility, is absorbed by organic matter, and has a high affinity for soil with low partitioning potential from soil matter to soil water. The purpose of this degradation study is to determine the effect of soil alkalinity on the longevity of termite protection when chlorpyrifos is applied as a termiticide in a range of Australian soils, particularly high-pH substrates. The study also examines the effects of initial soil concentration on the degradation of chlorpyrifos in the range of soils. At an initial soil concentration of 1000 mg kg(-)(1) for termite control, the degradation rate of chlorpyrifos is very strongly retarded in soils tested when compared with lower soil concentrations of 100 and 10 mg kg(-)(1) in the same soils. The degradation data correlated with a logarithmic model of decay, and it was thus possible to produce half-lives and predict likely periods of termite control. Average half-lives for all soils for the three concentrations were 385, 155, and 41 days, respectively. Soil pH had no effect on the rate of degradation at all concentrations tested.

[The effect of changing the association properties of psychopharmaceuticals in colloidal solutions on their liberation. 4. The effect of chemical structure as well as environmental conditions on the elevation of critical micelle formation concentration and reduction of micelle weight with hydrotropic material]. / Freisetzungsbeeinflussung von Psychopharmaka in kolloidalen Lösungen durch Veränderung ihrer Assoziationseigenschaften. 4. Mitteilung: Einflüsse der chemischen Struktur sowie der Milieubedingungen auf die Erhöhung der kritischen Mizellbildungskonzentration und die Verminderung des Mizellgewichtes durch hydrotrope Stoffe.

As shown by 8 different tri- and tetracyclic psychiatric drugs the authors demonstrated that the rate of desaggregation is markedly influenced by the chemical structure of drugs. In presence of 0.1 mol/l nicotinamide the cmc increased between 1.3 times for Maprotiline-HCl and 3.5 times for Chlorprothixene-HCl in acetate buffer pH 5.0; I = 0.154. Investigations about influences on the micellar weights showed for Flupenthixol-di HCl, Clomipramine-HCl and Melitracen-HCl decreases of 21.5, 16.1 and 14.0 per cent conferred by addition of 0.3 mol/l nicotinamide. There was a good correlation to the increase of the cmc. Different hydrotropic substances may show great differences of influence on the micellar weights and the cmc respectively. The micellar weight of Flupenthixoldi HCl for example reduces for about 17 per cent by concentrations of 0.2 mol/l nicotinamide or 1 mol/l propandiol-1.2, but the cmc increases to the 3.6- and 1.4fold value.