Influence of moisture on the persistence of chlorpyrifos and chlorfenvinphos in sterile and natural mineral and organic soils
Title:
Influence of moisture on the persistence of chlorpyrifos and chlorfenvinphos in sterile and natural mineral and organic soils
Author:
Miles, J. R. W. Harris, C. R. Tu, C. M.
Appeared in:
Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes
Paging:
Volume 19 (1984) nr. 2 pages 237-243
Year:
1984
Contents:
Chlorpyrifos and chlorfenvinphos persistences were examined (concentration - 10 μg/g) in sterile and natural mineral (sandy loam) and organic (muck) soils at 4 moisture levels; air-dry, and 20, 40 and 60% of moisture holding capacity at 28°C. Chlorpyrifos was fairly stable in sterile soils, with ca. 50% remaining at the end of the 24 wk experiment. In natural soils, chlorpyrifos disappeared most rapidly from air-dry soil; slightly less rapidly from the 3 moist soils. Chlorfenvinphos was fairly stable in sterile soils, with >50% remaining at 24 wk at all moisture levels. In natural soils chlorfenvinphos, in contrast to chlorpyrifos, was more stable in air-dry soils. In moist loam the disappearance rates of chlorfenvinphos were similar for all 3 moisture levels; but in moist muck its disappearance was proportional to the moisture content. “Cis”; (ca 10% of the technical material) and “trans”; chlorfenvinphos disappeared at the same rate in sterile soils. In natural soils the “cis”; isomer disappeared about twice as fast, suggesting specific microbial degradation.