Replicated field experiments were conducted at three locations in North Carolina to study the disappearance of parathion from flue-cured tobacco. Immediately after application, parathion residues on green leaves, averaged over locations, were 51.0 and 78.8 ppm, respectively, for the 0.56 and 1.12 kg/ha rates. These residues dropped to 0.63 and 1.50 ppm for the two rates at five days after application. Parathion residues disappeared from green leaves most rapidly during the first 24 hr after application; the loss was over 95 percent in five days and over 99 percent at nine days after application. Residues of paraoxon on green leaves were highest one day after application when concentrations averaged 1.4 and 3.0 ppm for application rates of 0.56 and 1.12 kg/ha, respectively. Loss of total parathion residues during flue-curing ranged from 53 to 87 percent with an average of 72 percent.

AbstractWhen 13.4 kg/ha of DDT were applied to cotton (Gossypium hirsutum L.) during the 1969 growing season, 2.83% was found in natural runoff between July 11, 1969 and January 5,1970. About 96% of the DDT in runoff was associated with suspended sediment. Of 26.8 kg/ha of toxaphene applied, 0.36% was detected in runoff, and 75% of the toxaphene in runoff was in the sediment fraction. When DDT and toxaphene were applied to the same plot (13.4 and 26.8 kg/ha, respectively, over the season) only 1.03% of the DDT was found in runoff, and the percentage for toxaphene was 0.61. A much greater percentage of DDT and toxaphene remained as soil residues than was found in runoff, but a high percentage of the pesticides applied was not recovered. Residues of DDT in water from a small pond within one experimental watershed ranged from <0.35 ppb before spraying to 13.4 ppb during the spraying season. Toxaphene residues in pond water varied from <1 ppb before spraying to 65 ppb about midseason.

OLNEY et al. (1962) showed that chlorinated hydrocarbon pesticides tend to accumulate in the fatty deposits of chickens. Wesley et al. (1966) presented evidence which suggested that starvation increased the depletion rate of DDT from the tissues of chickens. Repeated cycles of 48 hours of starvation followed by 24 hours of feeding non-contaminated feed reduced body fat content and body burden of DDT when starved chicks were grown to the same body weight as full-fed controls (Donaldson et al., 1968). The results with starvation suggest that any treatments which tend to decrease body fat may also tend to increase the rate of elimination of DDT residues from the body. Turner et al. (1946) showed that feeding iodinated casein to laying hens resulted in decreased deposition of subcutaneous and carcass fat. Stamler et al. (1950) found that the feeding of dessicated thyroid to chicks reduced the lipemia and fatty liver produced…