Metabolism captan

Biological and Chemical Behavior of Perhalogen-methylmercapto Fungicides Metabolism and in Vitro Reactions of Dichlofluanid in Comparison with Captan... 

This report will mainly be concerned with the metabolic fate of dichlofluanid in strawberries, captan in spinach and soil as well as in vitro reactions of diohlofluanid with cell thiols and the comparative behavior of metabolites in the Ames assay. 

Special attempts were made to identify carbonyl sulfide as a metabolite of dichlofluanld because it would help us understand the metabolic pathway. In a previous investigation into the metabolism of captan, CS was found as a metabolite (4), while in a latter study, COS was reported ( 17). Viles reagent (18) often used by many investigators for this purpose, proved to be unsuitable because of the possible presence of carbon disulfide. Both COS and CS2 give colored copper chelates that can not be quantitatively separated by tic. Furthermore, analysis of the mixtu-... 

Our initial studies on the metabolic pathway of captan in spinach point to similarities with dichlo-fluanid metabolism in strawberries. Preplanting treatment of soil with I C-captan followed by spinach cultivation for 34 days in a closed controlled ventilated cultivating system resulted in a recovery of 87% radiocarbon (Table III). The ma or amount (49%) was found in the soil, 19% in the spinach and 19% as carbon dioxide. Bligh-Dyer extraction of the spinach gave 7.4% of the l c-iabel in the chloroform and metha-... 

At the present time, the biomarkers that correlate best with exposure are metabolite levels in the urine (Baselt 1980 Beauchamp et al. 1983 Campbell et al. 1985 Lieben 1974 WHO 1986). The iodine-azide and the TTCA tests, which measure the presence of urinary carbon disulfide metabolites, have been shown to correlate well with actual exposure. However, the iodine-azide test is nonspecific (Dox et al. 1992). TTCA is produced in humans after exposure to Antabuse and in rats after exposure to Captan (Cox et al. 1992). Moreover, other investigations are necessary in order to determine whether the interaction of carbon disulfide with other substances (such as hydrogen sulfide, drugs, carbon tetrachloride, malathion, and alcohol), disease states, and variations in diet and in individual metabolism, as well as other factors, could confound the results of the iodine-azide test and the TTCA test for carbon disulfide exposure. Baseline urine, breath, and blood samples are necessary to correct for non-workplace exposures. For exposures around hazardous waste sites, the influence of workplace exposures must also be corrected for in this manner. 

Captan Loss of this compound from soil can be explained by its low persistence in this compartment. But the high proportion detected in the air is inconsistent with its low Henry s law constant. This response is due to the fact that unlike the other compounds tested that have the incorporated in a stable ring, the label is in a —SCCI3 fragment that is readily metabolized to CO2. Movement through soil would also be limited by the rapid metabolism of this compound. 

Schuphan, L., Westphal, D., Haque, A. Ebing, W. (1981). Biological and chemical behaviour of perhalogenmethylmercapto fungicides Metabolism and in-vitro reactions of dichlofluanid in comparison with captan. Am. Chem. Soc., Symposium Series 158, 85-96. 

Schuphan, L., Westphal, D., Haque, A. and Ebing, W., 1981. Biological and chemical behaviour of perhalogenmethylmercapto fungicides Metabolism and in-vitro reactions of dichlofluanid in comparison with captan. Am. Chem. Soc., Symposium Series, 158, 85-96. Schweinfurth, H. A. and Giinzel, P., 1987. The tributyltins Mammalian toxicity and risk evaluation for humans. Proc. Oceans, 87, 1421-37. Scott, C. R. and Wolf, P. A., 1962. Antibacterial activity of a series of quaternaries prepared from hexamethylenetetramine and halohydro-carbons. Appl Microbiol. 10, 211-16. 

Strain. By these criteria, methyl methanesulfonate, A -acetoxyfluorenylacet-amide, captan, and others are preferential inhibitors of the pol Ai strain (Tables 7 and 8). On the other hand, streptomycin and chloramphenicol, although they induce lethality in both indicator strains, do not preferentially kill the pol Ar strain (SI = 1.12 and 1.02, respectively). It should be noted that this procedure is compatible with metabolic activation. Thus, the precarcinogens 2-aminofluorene and cyclophosphamide, which require metabolic activation by hepatic enzymes, do not preferentially inhibit the pol Ai strain in the absence of rat liver microsomes, but do so in the presence of this preparation (Tables 7 and 8). This procedure has the added advantage that results obtained by this modified pol Ai assay are expressed quantitatively, rather than as differences in the diameters of the zones of growth inhibition. As will be seen below, this modified procedure greatly increases the usefulness of the pol A assay (Table 9). 

To obtain a suitable coating viscosity, and to prevent settling of filler particles, thickeners are often used. These are often low-cost natural products based on cellulose or casein. These are readily metabolized by many bacteria and fungi therefore, a biocide should be included. Biocides in powder form such as Captan (R.T. Vanderbilt) or Zinc Omadine (Akcros) can be dispersed with fillers and pigments. A useful starting point level is 1 percent by weight of the natural polymer to be protected. Alternatively, a biocide water dispersion, such as Nuocide 404-D (40.4%, International Specialty Products), can be used. 

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