Fate of ethion in canals draining a Florida citrus grove

Abstract

6-month incubation (Table 111). In whole grain of both treatments, malathion monocarboxylic acid was the most prevalent degradation product, followed by an unknown compound. The dockage fraction, however, contained larger quantities of the unknown compound than malathion monocarboxylic acid. Both treatments contained smaller amounts of malathion and larger amounts of the degradation products after 6 months than after 2 months. Malaoxon was not found in the grain. The unknown compound did not correspond to malathion, malaoxon, malathion mono-or dicarboxylic acid, malaoxon mono-or dicarboxylic acid, demethyl malathion, diethyl mercaptosuccinate, thiomalic acid, or the alkyl phosphate metabolites. Malathion dicarboxylic acid was not detectable in this study because it did not contain the radiocarbon label. ACKNOWLEDGMENTWe are grateful to R. Beeman, who developed and assisted in the HPLC analysis, and to T. Hopkins for helpful suggestions concerning sample oxidation.Registry No. Malathion, 121-75-5; malathion monocarboxylic acid, 35884-76-5.

Microbial degradation of the organophosphate pesticide, Ethion

“…In this case, flask sterility was confirmed through microscopic examination and plating on nutrient agar. Similarly, Dierberger and Pfeuffer have reported that the half‐life of Ethion in buffered (pH 7) distilled water at 30 °C is 20.8 weeks [9]. Thus, the increase in OD660 was not due to infection or hydrolysis of the Ethion.…”

“…The lack of these components in Ethion may support its significantly faster microbial degradation. The abiotic hydrolytic degradation products of Ethion; Ethion Monoxon, Ethion Dioxon, O,O ‐diethylthiophosphate and Thio‐formaldehyde were not observed using GC–MS [9,19]. Their absence may be due to a number of factors, however it seems most likely that Ethion and its degradation products were rapidly utilised for microbial growth.…”

“…There is considerable concern however for the safety of landfill disposal in relation to the long‐term stability of pollutants as well as potential hazards involved in transport of contaminated waste [8]. While the hydrolysis and biodegradation of Ethion in a variety of environments has been demonstrated by Dierberger and Pfeuffer [9], to the best of our knowledge, this is the first report of its biodegradation by individual isolates which may have potential in bioremediation technologies.…”