Biodegradation Methoxychlor

Baarschers WH, AI Bharaty, J Elvish (1982) The biodegradation of methoxychlor by Klebsiella pneumoniae. Can J Microbiol 28 176-179. 

Methoxychlor. Methoxychlor is strongly adsorbed to the soil and does not leach, and volatilization is slow. There is no evidence for oxidation, and although photolysis is rapid in aquatic systems, it is assumed not to occur in the soil environment. The hydrolysis half-life is a year in aquatic systems (33) and probably longer in soil systems because of adsorption. Biodegradation does occur in soil systems, however, with a half-life of from 1 to 3 weeks (34). Methoxychlor would not persist in the soil environment. 

In a model aquatic ecosystem, methoxychlor degraded to ethanol, dihydroxy ethane, dihy-droxyethylene, and unidentified polar metabolites (Metcalf et al, 1971). Kapoor et al. (1970) also studied the biodegradation of methoxychlor in a model ecosystem containing snails, plankton, mosquito larvae, Daphnia magna, and mosquito fish Gambusia affinis). The following metabolites were identified 2-(/5-methoxyphenyl)-2-(p-hydroxyphenyl)-l,l,l-trichloroethane, 2,2-bis (p-hydroxyphenyl) -1,1,1 -trichloroethane, 2,2-bis (p-hydroxyphenyl) -1,1,1 -trichloroethylene,... 

Fogel, S., Lancione, R., Sewall, A., and Boething, R.S. Enhanced biodegradation of methoxychlor in soil under enhanced environmental conditions, Appl. Environ. Microbiol, 44(1) 113-120, 1982. 

The comparative figures for methoxychlor, a biodegradable pesticide, were 1343 and 206, respectively. Although it is... 

Although nonpolar compounds tend to dissolve and remain in fatty tissues, polar substances are more water soluble, and more readily excreted into an environment where they may be degraded by other organisms. Explain why methoxychlor is more biodegradable than DDT. 

Methoxychlor. Its chemical structure and properties are similar to those of DDT, but it biodegrades more easily. Aquatic organisms metabolize it and transform it into other less toxic substances and therefore it does not lead to significant bioaccumulation phenomena. 

Methoxychlor is an insecticide that was intended to take DDT s place because it is not as soluble in fatty tissues and is more readily biodegradable. It, too, can accumulate in the environment, however, so its use was also banned—in 2002 in the European Union and in 2003 in the United States. Why is methoxychlor less soluble in fatty tissues than DDT ... 

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