Title : Observations on the influence of water and soil pH on the persistence of insecticides - Chapman_1982_J.Environ.Sci.Health.[B]_17_487
Author(s) : Chapman RA , Cole CM
Ref : J Environ Sci Health [B] , 17 :487 , 1982
Abstract :

The pH-disappearance rate profiles were determined at ca. 25 degrees C for 24 insecticides at 4 or 5 pH values over the range 4.5 to 8.0 in sterile phosphate buffers prepared in water-ethanol (99:1 v/v). Half-lives measured at pH 8 were generally smaller than at lower pH values. Changes in half lives between pH 8.0 and 4.5 were largest (greater than 1000x) for the aryl carbamates, carbofuran and carbaryl, the oxime carbamate, oxamyl, and the organophosphorus insecticide, trichlorfon. In contrast, half lives of phorate, terbufos, heptachlor, fensulfothion and aldicarb were affected only slightly by pH changes. Under the experimental conditions described half lives at pH8 varied from 1-2 days for trichlorfon and oxamyl to greater than 1 year for fensulfothion and cypermethrin. Insecticide persistence on alumina (acid, neutral and basic), mineral soils amended with aluminum sulfate or calcium hydroxide to different pH values and four natural soils of different pH was examined. No correlation was observed between the measured pH of these solids and the rate of disappearance of selected insecticides applied to them. These observations demonstrate the difficulty of extrapolating the pH dependent disappearance behaviour observed in homogeneous solution to partially solid heterogeneous systems such as soil.

PubMedSearch : Chapman_1982_J.Environ.Sci.Health.[B]_17_487
PubMedID: 7175098

Related information

Inhibitor Aldicarb    Carbaryl    Carbofuran    Oxamyl    Terbufos

Citations formats

Chapman RA, Cole CM (1982)
Observations on the influence of water and soil pH on the persistence of insecticides
J Environ Sci Health [B] 17 :487

Chapman RA, Cole CM (1982)
J Environ Sci Health [B] 17 :487