Observations on the influence of water and soil pH on the persistence of insecticides
- 1 January 1982
- journal article
- research article
- Published by Taylor & Francis in Journal of Environmental Science and Health, Part B
- Vol. 17 (5) , 487-504
- https://doi.org/10.1080/03601238209372336
Abstract
The pH‐disappearance rate profiles were determined at ca. 25°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 (>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 >1 year for fensulfothion and cyper‐methrin. 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.Keywords
This publication has 44 references indexed in Scilit:
- LABORATORY STUDIES ON THE PERSISTENCE AND BEHAVIOUR IN SOIL OF FOUR PYRETHROID INSECTICIDESThe Canadian Entomologist, 1981
- INSECTICIDAL ACTIVITY AND PERSISTENCE OF PHORATE, PHORATE SULFOXIDE, AND PHORATE SULFONE IN SOILSThe Canadian Entomologist, 1980
- Persistence of eight organophosporus insecticides in sterile and non-sterile mineral and organic soilsBulletin of Environmental Contamination and Toxicology, 1979
- Degradation of selected organophosphate pesticides in water and soilJournal of Agricultural and Food Chemistry, 1979
- Degradation of carbofuran by soil microorganismsBulletin of Environmental Contamination and Toxicology, 1976
- Persistence in soil and losses in runoff of soil-incorporated carbaryl in a small watershedJournal of Agricultural and Food Chemistry, 1974
- Influence of some soil characteristics on the dissipation rate of landrin insecticideBulletin of Environmental Contamination and Toxicology, 1974
- Soil Degradation of Diazinon, a Phosphorothioate Insecticide1Agronomy Journal, 1967
- Insecticidal Phosphates Obtained by a New Rearrangement Reaction1aJournal of the American Chemical Society, 1955
- The New Insecticide O,O-Dimethyl 2,2,2-Trichloro-1-hydroxyethylphosphonateJournal of the American Chemical Society, 1955