Human exposure to DEF/merphos
The harvest-aid herbicides DEF (S,S,S-tributylphosphorotrithioate) and merphos(S,S,S-tributylphosphorotrithioite) have been employed for defoliation of cotton for over 20 years. These compounds are readily taken up by the plant leaf and induce and accelerate abscission. There is little information available on the chemical characteristics of these compounds or on their environmental fate. DEF, however, appears to have very low vapor pressure and is also apparently quite stable. For the most part, environmental fate and human exposure estimates for these compounds have been based on data derived from parathion studies. While these estimates may prevail to some degree, the compounds are not completely comparative, as for example, the fact that parathion hydrolyzes readily under alkaline conditions while DEF reportedly does not.
KeywordsVortex Sulfide Convection Acetone Disulfide
Unable to display preview. Download preview PDF.
- — —, P. R. Timmons, and B. L. Reichert: Delayed neurotoxic and late acuteeffects of S,S,S-tributyl phosphorotrithioate on the hen: Effect of route of administration. Neurotoxicol. 1, 425 (1979 b).Google Scholar
- DHEW (NIOSH) Publ. No. 78–213: Criteria for a recommended standard … Occupation exposure to n-alkane mono thiols, cyclohexanethiol, benzenethiol (1978).Google Scholar
- Mobay Chemical Co.: Personal Communication (1981).Google Scholar
- Peoples, S. A., K. Maddy, P. R. Datta, L. Johnston, C. Smith, D. Conrad, and C. Cooper: Monitoring of potential exposures of mixer-loaders, pilots, and flaggers during application of tributyl phosphorotrithioate (DEF) and tributyl phosphorotrithioite (Folex) to cotton fields in the San Joaquin Valley of California in 1979. Worker Health and Safety Unit, Calif. Dept. Food and Agr. HS-676 (1979).Google Scholar
- Personnel air samplers: Union Industrial Equipment Corporation, Fall River, Mass. Modified by N. Akesson, Dept. Agricultural Engineering, Univ. Calif., Davis.Google Scholar