Bromacil in Lakeland Soil Ground Water
1978
Hebb, Edwin A. | Wheeler, Willis B.
The objective of this study was to evaluate the probable magnitude of the problem of the leaching of pesticides into ground water under extreme conditions: a sandy soil low in organic matter, a persistent and mobile herbicide applied at a high rate, plentiful rainfall, and a water table within 6 m. Bromacil (5-bromo-3-sec-butyl-6-methyluracil) was applied at the rate of 22 kg/ha to a Lakeland sand bearing scrub vegetation of small oaks and poor grasses. Ground water (at depths ranging from 4.5 to 6 m) was sampled from bromacil residue at weekly intervals for 2 years. Residue was first found in the ground water 3 mo after application and was highest (1.25 ppm) 1 month later. Thereafter the amount declined to <0.1 ppm in about a year and <0.001 ppm in 2 years. Peaks in residues generally followed periods of increased rainfall by about 2 weeks. Residues (0.24 ppm) were still detected in the surface soil 2 years after application.
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