Mirex half-life

Mirex was rapidly cleared from the blood of rats following an intravenous injection of 10 mg/kg (Byrd et al. 1982). Mirex blood levels at 8 hours were less than 4% of the levels seen 2 minutes after injection. Pharmacokinetic modeling predicted that intravenously administered mirex was quickly cleared from the blood into a rapidly equilibrating compartment. Over the next several weeks, mirex was redistributed to a slowly equilibrating compartment, which acted as a depot for mirex storage (Byrd et al. 1982). The biological half-life of mirex was estimated to be 435 days (Byrd et al. 1982). 

Epidemiological and Human Dosimetry Studies. No epidemiological studies are available for mirex exposure. Individuals living in areas that have been treated for fire ants or near hazardous waste sites containing mirex or chlordecone are the most likely exposed subpopulation because of the relatively long half-lives of these substances-estimated half-life of 10 years-(Carlson et al. 1976 ... 

The half-life was reduced sixfold in the two former cases and twofold in the latter. Benzamide and reduction photoproducts (mono- and dichlorinated derivatives) could be characterized by GC-MS. Chlorothalonil, which bears several electron-withdrawing substituents, could be only oxidized by a strong oxidant and the involvement of hydroxyl radicals was very likely. Photoreduction also occurred. Since chlorothalonil is very poorly soluble in water, it might sorb to DOM and react with solvated electrons produced within the hydrophobic zones of DOM in a similar way to Mirex. 

The photoreaction of lindane was markedly enhanced in solutions of s commercial soil fulvic acid (Contech) and in natural water samples with higj DOM concentrations (DOC 10-27 mg of C/L) with estimated half-lives a 1-10 days versus a half-life in excess of 100 days in air-saturated distilled watei (Table III). Moreover, Mudambi and Hassett (31) reported that the high chlorinated pollutant, mirex, is reductively dehalogenated to photomirex wit a half-life of 6-8 days under sunlight in Lake Ontario water (eq 15). 

Mirex is rapidly adsorbed onto various organic particles in the water column, including algae, and eventually is removed to the sediments. Not surprisingly, mirex has a long half-life in terrestrial and aquatic sediments large fractional residues were detected at... 

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