Vapor-phase photochemistry of pesticides

Woodrow, James E.; Crosby, Donald G.; Seiber, James N.

doi:10.1007/978-1-4612-5462-1_9

Cited by 34 publications

(30 citation statements)

References 25 publications

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“…It is the family of oxon phosphorus esters which is most dangerous . Their atmospheric degradation has been quantified empirically and it occurs in on the order of hours to days depending on local conditions and on molecular structure (Woodrow et al, 1983). Overall breakdown mechanisms are not known, but initiation has been studied for model compounds such as trimethyl phosphate (Winer and Atkinson, 1990).…”

Section: Discussionmentioning

confidence: 99%

“…A complex sequence of evaporation, revolatilization, and resuspension steps is involved (Woodrow et al, 1983;Woodrow et al, 1986). Early concerns revolved around DDT and its decay products (Cory et al, 1970;Metcalf, 1982), and it rapidly became clear that they were sufficiently stable to mobilize on the regional scale (Wania and MacKay, 1993).…”

Section: Related Pesticidesmentioning

confidence: 99%

“…Winer and Atkinson (I 990) single out hydrogen abstraction by the hydroxyl as the major atmospheric loss channel for most of the organophosphorus pesticides. Thions were converted to oxons with a yield of around lo%, perhaps explaining results such as those of Woodrow et al (1983) or Seiber et al (1993). Product identification in the studies was restricted to measurement of oxons (Atkinson et al, 1989).…”

Section: Related Pesticidesmentioning

confidence: 99%

“…Time scales for parathion oxidations in the atmosphere (Woodrow et al, 1983 Figure 1. Propylene decay through ozone reaction in the mechanism of Falls and Seinfeld (1978).…”

mentioning

confidence: 99%

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Pathways for the oxidation of sarin in urban atmospheres

Elliott

Streit

Gaffney

et al. 1999

Environ. Sci. & Pollut. Res.

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Section: Discussionmentioning

confidence: 99%

Section: Related Pesticidesmentioning

confidence: 99%

Section: Related Pesticidesmentioning

confidence: 99%

“…Time scales for parathion oxidations in the atmosphere (Woodrow et al, 1983 Figure 1. Propylene decay through ozone reaction in the mechanism of Falls and Seinfeld (1978).…”

mentioning

confidence: 99%

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Pathways for the oxidation of sarin in urban atmospheres

Elliott

Streit

Gaffney

et al. 1999

Environ. Sci. & Pollut. Res.

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“…Such experiments, which mimic, for example reactions in the condensed phase, may in some cases be helpful for the description of the photolytic behaviour of a pesticide in air and its removal from the atmosphere. Thus in one study [78], which investigated the fate of different pesticides under simulated atmospheric conditions and field conditions, the substances were vaporised in a special chamber and irradiated with UV-light, in some cases in the presence of ozone. During the field study downwind air was sampled at defined distances from a treated field.…”

Section: Experimental Techniquesmentioning

confidence: 99%

Significance of the Long Range Transport of Pesticides in the Atmosphere

Unsworth¹,

Wauchope²,

Klein³

et al. 1999

Pure and Applied Chemistry

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Since the 1960s there has been a growing body of data regarding the presence of pesticides in the atmosphere. The monitoring results obtained show that traces of pesticides may undergo long range transport and be deposited considerable distances away from the treatment areas, including remote areas such as the Arctic and Antarctic regions. Pesticides have been found in air, rain, cloud water, fog and snow. The appearance and subsequent behaviour of pesticides in the atmosphere are complex processes and the concentrations found depend on several variables such as their volatility, photostability, method of application and extent of use. Whilst volatility of pesticides can be linked to their Henry's Law constant this is very much a simplification since it is also influenced by the surfaces treated, e.g. soil or leaves, and by the extent to which aerosols are formed during the application. The disappearance of pesticides from the atmosphere is due to hydrolysis, indirect photolysis via OH ؒ radicals and to deposition in rain. Pesticides which are resistant to hydrolysis and photolysis can be transported over great distances, for example, organochlorine insecticides have been detected in the Arctic regions. In general, concentrations in rainwater are, when detected, in the low or sub g/L range and highest concentrations are found during the time of application. The use of fugacity models has been shown to be a useful approach to predict concentrations in air. Under most conditions the presence of pesticides in air, or rainwater, has no significant effects on nontarget systems, including direct and indirect effects. Exceptions to this are damage by auxintype herbicides to sensitive plants which has resulted on restrictions in their use in certain areas and transient chlorotic spotting thought to be caused by drift of aerosols from application of low rate sulfonyl urea herbicides. For animal species one possible exception has been postulated. This is for persistent organochlorine pesticides in Arctic regions where, due to the very oligotrophic nature of the Arctic ocean, they are more liable to bioaccumulate and be transported in the food web giving enhanced levels in mothers' milk. THE IUPAC COMMISSION ON AGROCHEMICALS AND THE ENVIRONMENT MAKES THE FOLLOWING RECOMMENDATIONSBased on the conclusions from this review, several recommendations for further areas of research are suggested. Since the factors governing the fate and behaviour of pesticides in the atmosphere are the same for any organic contaminant, whether from natural or anthropogenic sources, research studies on pesticides in air should be considered in the same way as any organic contaminant in the atmosphere.

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Airborne residues resulting from use of methyl parathion, molinate and thiobencarb on rice in the sacramento valley, California

Seiber

McChesney

Woodrow

1989

Environmental Toxicology and Chemistry

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In connection with requirements of California's Toxic Air Contaminant Act, 24‐h ambient air samples were collected using an XAD‐4 resin trap technique capable of simultaneously collecting methyl parathion, methyl paraoxon, molinate and thiobencarb. Sampling was conducted on rooftops of public buildings located in four towns in two counties where methyl parathion, molinate and thiobencarb were used in significant quantities, and at a background site located in a county where no use occurred, for four intervals each week for 5 weeks during the springtime application period of 1986. Satisfactory recoveries (greater than 66%) were obtained from dynamic spiking experiments, and the precision from field replicates was consistently less than 50% relative standard deviation using a protocol designed to accommodate a large number of samples. Daily maximum average concentrations (and the range in averages for all sites over the 19 and 20 sampling days in the two‐county use area) were 25.7 ng/m3 (0.2‐6.2 ng/m3) for methyl parathion, 3.1 ng/m3 (<0.5‐0.8 ng/m3) for methyl paraoxon, 1,720 ng/m3 (60‐650 ng/m3) for molinate and 250 ng/m3 (12.9‐67.8 ng/m3) for thiobencarb. Concentrations correlated well with reported uses of methyl parathion and molinate in the general vicinity of the sampling sites. The likely sources of observed residue levels, based upon the method of application and pesticide physicochemical properties, were spray drift during application for methyl parathion, vapor‐phase oxidation of parent thion for methyl paraoxon, and postapplication volatilization from field water for molinate and thiobencarb.

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Vapor-phase photochemistry of pesticides

Cited by 34 publications

References 25 publications

Pathways for the oxidation of sarin in urban atmospheres

Pathways for the oxidation of sarin in urban atmospheres

Significance of the Long Range Transport of Pesticides in the Atmosphere

Airborne residues resulting from use of methyl parathion, molinate and thiobencarb on rice in the sacramento valley, California

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