Methidathion toxicity

ChemicaPPhysical. Emits toxic fumes of phosphorus, nitrogen, and sulfur oxides when heated to decomposition (Sax and Lewis, 1987). Methidathion oxon was also found in fogwater collected near Earlier, CA (Glotfelty et ah, 1990). It was suggested that methidathion was oxidized in the atmosphere during daylight hours prior to its partitioning from the vapor phase into the fog. On 12 January 1986, the distributions of parathion (0.45 ng/my in the vapor phase, dissolved phase, air particles, and water particles were 57.5, 25.4, 16.8, and 0.3%, respectively. For methidathion oxon (0.84 ng/m3), the distribution in the vapor phase, dissolved phase, air particles, and water particles were <7.1, 20.8, 78.6, and 0.1%, respectively. 

The procedure involves converting oxon to thion toxicity equivalents by multiplying the oxon value by its relative toxicity (ED of thion r ED,.q of oxon) in Table I. The ED. value is the aermal dose in ug/cnr of total body surface which produces 50% inhibition of red cell ChE activity 72 hours after application. The total thion and oxon level is then divided by the thion toxicity equivalents and the factor is multiplied by the safe level established for thion in Table I. This procedure was conducted for the dislodgeable residues of parathion-paraoxon, methidathion-methidathion oxon, and azinphosmethyl-azinphosmethyl oxon. The safe levels for the total disloggeable residues were determined to be 0.06, 0.2 and 1.6 ug/cm, respectively, for... 

Induction of glutathione S-transferases by phenobarbital in houseflies provides some protection against the toxicity of methyl parathion, methyl paraoxon, azinphosmethyl, and methidathion. Similarly, induction of glutathione S-transferase by host plants in fall armyworm larvae protects the larvae against organophosphate insecticides. Larvae fed... 

Methyl parathion, methamidophos, and methidathion, all too often found in dead bee samples, are hazardous both for the environment and for man and reflect a non-professional approach to farming and above all a lack of respect for the territory. There is also the issue of fenoxycarb. The sale and use of this compound is banned throughout Italy (Ministerial Decree 8.8.1995 G.U. n. 189 of 14.8.1995, an exception being made only for the province of Bolzano), in view of its toxic effects on beneficial ento-mofauna. Nonetheless, residues of this compound were found in a bee sample taken from station OZZ 3 in June. 

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