Abstract
Laboratory studies on the breakdown of several organophosphate pesticides both in aqueous solution and moist soil were conducted. The hydrolysis rates of phosmet, dialifor, malathion, methyl chlorpyrifos, dicapthon, chlorpyrifos, and parathion were measured at 20 and 37.5 °C (pH 7.4) in an aqueous system.A similar studywas carried out at 20 °C and pH 6.1. The half-lives at 20 °C (pH 7.4) range from 7.1h for phosmet to 130 days for parathion; the corresponding rates at 37.5 °C are approximately five-seven times greater than those at 20 °C. The rate equations at pH 7.4 were calculated from the 20 and 37.5°C data in an Arrhenius form : k = A exp(-Ea/RT). In moist soil (pH 6.2), degradation rates were measured at pesticide concentrations of approximately 1.0 and 0.1 ppm in a Willamette clay loam soil at a moisture level of 50% of field capacity. A comparison of the 20 °C half-lives for phosmet and dialifor in water and in moist soil at comparable pH indicates an appreciable increase in persistence for these two compounds, but little for the others in the soil-water system. This study was intended to evaluate the stabilities of several agricultural pesticides.
| Original language | English |
|---|---|
| Pages (from-to) | 706-708 |
| Number of pages | 3 |
| Journal | Journal of Agricultural and Food Chemistry |
| Volume | 27 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1979 Feb 1 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Agricultural and Biological Sciences(all)
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Degradation of Selected Organophosphate Pesticides in Water and Soil. / Freed, Virgil H.; Chiou, Cary T.; Schmedding, David W.
In: Journal of Agricultural and Food Chemistry, Vol. 27, No. 4, 01.02.1979, p. 706-708.Research output: Contribution to journal › Article
TY - JOUR
T1 - Degradation of Selected Organophosphate Pesticides in Water and Soil
AU - Freed, Virgil H.
AU - Chiou, Cary T.
AU - Schmedding, David W.
PY - 1979/2/1
Y1 - 1979/2/1
N2 - Laboratory studies on the breakdown of several organophosphate pesticides both in aqueous solution and moist soil were conducted. The hydrolysis rates of phosmet, dialifor, malathion, methyl chlorpyrifos, dicapthon, chlorpyrifos, and parathion were measured at 20 and 37.5 °C (pH 7.4) in an aqueous system.A similar studywas carried out at 20 °C and pH 6.1. The half-lives at 20 °C (pH 7.4) range from 7.1h for phosmet to 130 days for parathion; the corresponding rates at 37.5 °C are approximately five-seven times greater than those at 20 °C. The rate equations at pH 7.4 were calculated from the 20 and 37.5°C data in an Arrhenius form : k = A exp(-Ea/RT). In moist soil (pH 6.2), degradation rates were measured at pesticide concentrations of approximately 1.0 and 0.1 ppm in a Willamette clay loam soil at a moisture level of 50% of field capacity. A comparison of the 20 °C half-lives for phosmet and dialifor in water and in moist soil at comparable pH indicates an appreciable increase in persistence for these two compounds, but little for the others in the soil-water system. This study was intended to evaluate the stabilities of several agricultural pesticides.
AB - Laboratory studies on the breakdown of several organophosphate pesticides both in aqueous solution and moist soil were conducted. The hydrolysis rates of phosmet, dialifor, malathion, methyl chlorpyrifos, dicapthon, chlorpyrifos, and parathion were measured at 20 and 37.5 °C (pH 7.4) in an aqueous system.A similar studywas carried out at 20 °C and pH 6.1. The half-lives at 20 °C (pH 7.4) range from 7.1h for phosmet to 130 days for parathion; the corresponding rates at 37.5 °C are approximately five-seven times greater than those at 20 °C. The rate equations at pH 7.4 were calculated from the 20 and 37.5°C data in an Arrhenius form : k = A exp(-Ea/RT). In moist soil (pH 6.2), degradation rates were measured at pesticide concentrations of approximately 1.0 and 0.1 ppm in a Willamette clay loam soil at a moisture level of 50% of field capacity. A comparison of the 20 °C half-lives for phosmet and dialifor in water and in moist soil at comparable pH indicates an appreciable increase in persistence for these two compounds, but little for the others in the soil-water system. This study was intended to evaluate the stabilities of several agricultural pesticides.
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U2 - 10.1021/jf60224a023
DO - 10.1021/jf60224a023
M3 - Article
AN - SCOPUS:0018389833
VL - 27
SP - 706
EP - 708
JO - Journal of Agricultural and Food Chemistry
JF - Journal of Agricultural and Food Chemistry
SN - 0021-8561
IS - 4
ER -