Chlorpyrifos persistence

Schimmel SC, Gamas RE, Patrick JM, et al. 1983. Acute toxicity, bioconcentration and persistence of AC 222,705, benthiocarb, chlorpyrifos, fenvalerate, methyl parathion and permethrin in the estuarine environment. J Agric Food Chem 31 104-113. 

Miles, J.R.W., C.R. Harris, and C.M. Tu. 1983. Influence of temperature on the persistence of chlorpyrifos and chlorfenvinphos in sterile and natural mineral and organic soils. Jour Environ. Sci. Health B 18 705-712. 

Kuhr, R.J. and H. Tashiro. 1978. Distribution and persistence of chlorpyrifos and diazinon applied to turf. Bull. Environ. Contam. Toxicol. 20 652-656. 

Chapman, R.A. and Chapman, P.C. Persistence of granular and ec formulations of chlorpyrifos in a mineral and organic soil incubated in open and closed containers, J. Environ. Sci Health, B21(6) 447-456, 1986. 

Getzin, L.W. Factors inflnencing the persistence and effectiveness of chlorpyrifos in soil, J. Econ. Entomol, 78 412-418,1985. Getzin, L.W. and Rosefield, I. Organophosphoms insecticide degradation by heat-labile snbstances in soil, J. Agric. Food Chem., 16(4) 598-601, 1968. 

Leuck, D.B., Jones, R.L., and Bowman, M.C. Chlorpyrifos-methyl insecticide residues their analysis and persistence in coastal bermuda grass and forage corn, J. Econ. Entomol, 69 287-290, 1975. 

In relation to this article, those chlorinated pesticides which are rapidly degraded in the environment, and considered as non-persistent, will not be discussed. Compounds such as atrazine, chlorpyrifos and the phenoxy acid herbicides (2,4-D), mecoprop, MCPA, etc.) all contain organic chlorine and may... 

Singh, B.K., Walker, A., and Wright, D.J., Persistence of chlorpyrifos, fenamiphos, chlorothalonil, and pendimethalin in soil and their effects on soil microbial characteristics, Bull. Environ. Contain. Toxicol., 69,181, 2002. 

Somewhat water-soluble pesticides such as acid herbicides will be washed from foliar surfaces and into subsurface soils by rainfall. For example, dislodge-able turf residues of 2,4-D after a 2.54-cm rainfall have been reported to be only 1-5% of those found at 4-8 h after application (Nishioka et al., 1996 USEPA, 1997c). However, dew or rain on aged turf residues may increase their dislodgeability (Nishioka et al, 1996). OP insecticides are semivolatile and will vaporize from surfaces after applications. Chlorpyrifos vaporizes rapidly from lawns if applied in aqueous formulations. Diazinon, which is used on lawns as well as indoors, dissipates even more rapidly. However, the persistence of OP... 

Sears, M.K., C. Bowhey, H. Braun, G.R. Stephenson (1987). Dislodgeable residues and persistence of diazinon, chlorpyrifos and isofenphos following their application to turf-grass, Pesticide Sci, 20, 223-231. 

Cholinesterase inhibition can sometimes persist for weeks thus, repeated exposures to small amounts of this material may result in accumulation of acetylcholinesterase inhibition with possible sudden-onset acute toxicity. Chlorpyrifos may be capable of causing organophosphate-induced delayed neurotoxicity in humans a massive overdose resulted in signs characteristic of delayed neurotoxicity. Animal studies generally indicate, however, that doses several times higher than the LD50 would be required to initiate delayed neurotoxicity. 

Chlorpyrifos is moderately persistent in soils, with a half-life from 2 weeks to 1 year depending on soil... 

In contrast to the other insecticides intensely investigated, chlorpyrifos showed no decrease in persistence in soil with a history of chlorpyrifos use. This corroborates earlier laboratory and field... 

Chlorovrifos. Prior applications of 3,5,6-trichloro-2-pyridinol, the hydrolysis product of chlorpyrifos, increased the persistence of chlorpyrifos (Table III). At the end of a 3-week incubation, there was about 5 to 10% increase in chlorpyrifos recovered in pyridinol-pretreated soils as compared with control soils. Increased persistence of a parent compound in soil pretreated with its degradation product is new to the literature. 

Chlorpyrifos is immobile in soil and is not available to microbes. However, its pyridinol hydrolysis product is relatively mobile its microbial toxicity and availability in soil may contribute to the increased persistence of chlorpyrifos observed in pyridinol-treated soils. 

---