Nonpersistent

In basic soils mepiquat chloride is nonpersistent and is rapidly degraded. There is a half-life of two years in other soil types, but 86—93% is metabolized within 30 days (10). Breakdown does not appear to be a function of microbial activity. 

Slow release formulations incorporate nonpersistent compounds, eg, methyl parathion, insect growth regulators, and sex pheromones, in a variety of granular, laminated, microencapsulated, and hoUow-ftber preparations. 

For those pesticides that are cometabolized, ie, not utilized as a growth substrate, the assumption of first-order kinetics is appropriate. The more accurate kinetic expression is actually pseudo-first-order kinetics, where the rate is dependent on both the pesticide concentration and the numbers of pesticide-degrading microorganisms. However, because of the difficulties in enumerating pesticide-transforming microorganisms, first-order rate constants, or half-hves, are typically reported. Based on kinetic constants, it is possible to rank the relative persistence of pesticides. Pesticides with half-hves of <10 days are considered to be relatively nonpersistent pesticides with half-hves of >100 days are considered to be relatively persistent. 

With the renewed interest in environmentally friendly products, ceUulose esters are being re-evaluated as a natural source of biodegradable thermoplastics. CeUulose acetates are potentiaUy biodegradable (152). Films prepared from a ceUulose acetate with a DS of 2.5 were shown to require only a 10—12 day incubation period for extensive degradation in an in vitro enrichment assay. Similarly, films prepared from a ceUulose acetate with a DS of 1.7 saw 70% degradation in 27 days in a wastewater treatment facUity, whereas films prepared from a ceUulose acetate with a DS of 2.5 required approximately 10 weeks for similar degradation to occur. The results of this work demonstrate that ceUulose acetate fibers and films are potentiaUy environmentally nonpersistant. 

Lichtenstein EP, Katan J, Anderegg BN. 1977. Binding of "persistent" and "nonpersistent" 14C-labelled insecticides in an agricultural soil. J Agric Food Chem 25 43-47. 

Persistency About 2 h in soil. Relatively nonpersistent on surfaces and water. 

Appearance Pure AC is a nonpersistent, colorless liquid that is highly... 

Type Chemical name A - nonpersistent 2-(dimethylamino)ethyl-dimethylphosphoramido fluoridate... 

Depending on the properties of the specific agent, unmodified G-series agents are classified as either nonpersistent or moderately persistent by the military. Evaporation rates range from near that of water down to that of light machine oil. 

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