Pesticide in air

Pesticides in air and on surfaces Pumped filters/sorbent tubes with gas chromatography 94... 

In a study to determine the concentrations of pesticides in air collected during times of peak pesticide use in California, air samples were collected at applications sites and at locations adjacent to the application sites (Baker et al. 1996). Of the samples collected adjacent to the application sites, 50% had levels of methyl parathion greater than the detectable limit of 0.2 ng/m, while 21% had levels of methyl paraoxon... 

Hoff RM, Muir DCG, Grift NP. 1992. Annual cycle of polychlorinated biphenyls and organohalogen pesticides in air in southern Ontario. 1. Air concentration data. Environ Sci Technol 26(2) 266-275. 

Pesticides may enter the atmosphere during spray applications of the formulated product, by volatilization, through management practices, via wind-distributed soil particles containing absorbed pesticides, etc. Several analytical methods have been reported over the last 30 years for the determination of pesticides in air, and all involve the passage of known volumes of air for a pre-defined time period through an adsorbent material to trap the desired analytes. These analytes are then extracted, concentrated, and analyzed. A few analytical methods have been reported for the determination of triazine compounds in air in the last decade. 

Sonication helps improve solid-liquid extractions. Usually a finely ground sample is covered with solvent and placed in an ultrasonic bath. The ultrasonic action facilitates dissolution, and the heating aids the extraction. There are many EPA methods for solids such as soils and sludges that use sonication for extraction. The type of solvent used is determined by the nature of the analytes. This technique is still in widespread use because of its simplicity and good extraction efficiency. For example, in research to determine the amount of pesticide in air after application to rice paddy systems, air samples collected on PUF were extracted by sonication, using acetone as the solvent. The extraction recoveries were between 92% and 103% [21]. 

Table XIV shows the levels of pesticides In air samples In the five field stations that had detectable levels. In general, the pesticide air levels found did compare favorably with the vapor pressure and residue levels of chemicals In the top 0-1 Inch surface of soil. These same conclusions have been made from previous studies (. However, levels were not always detected In the quantities that might be predicted ( ), perhaps due to other variables such as Inconsistent wetting of the beds, oil film In some of the beds and unidentified foreign matter on the surface of some beds Although the beds were all made up of sandy loam, the degree of sand, silt and clay varied appreciably.

Pesticides In Air Samples Taken Over U.C Evaporation Beds During 1982... 

J. R. Collection of Chlorpyrifos and Other Pesticides in Air on Chemically Bonded Sorbents Anal. Chem., 1978, 5J0, 251. 

Airborne pesticides have been collected by a variety of techniques using filters, impingers, bubblers, solid sorbents, polyurethane foams, and combinations thereof. Sampling for pesticides in air is complicated because specific pesticides may be present as particulate or as a vapor or both, depending on the concentration of the pesticide in the atmosphere, the equilibrium vapor concentration, and the temperature (1-6). 

Test atmospheres of known concentration of the pesticide in air were dynamically generated at levels of twice, one-half, and at the OSHA standard for the specific pesticide. 

Seiber JN, Glotfelty DW, Lucas AD, et al. 1990. A multiresidue method by high performance liquid chromatography-based fractionation and gas chromatographic determination of trace levels of pesticides in air and water. Arch Environ Contam Toxicol 19 583-592. 

Table 10 Average concentrations (pg/m3) of organochlorine pesticides in air samples and in wet precipitation (ng/L) in Big Creek watershed and at closest IADN sites (Sturgeon Point and Point Petre)...

Air analysis for some of the individual pesticides of this class has been published by NIOSH. These pesticides include mevinphos, TEPP, ronnel, malathion, parathion, EPN, and demeton (NIOSH Methods 2503, 2504, 1450). In general, pesticides in air may be trapped over various filters, such as Chro-mosorb 102, cellulose ester, XAD-2, PTFE membrane (1 pm), or a glass fiber filter. The analyte(s) are extracted from the filter or the sorbent tube with toluene or any other suitable organic solvent. The extract is analyzed by GC (using a NPD or FPD) or by GC/MS. The column conditions and the characteristic ions for compound identifications are presented in the preceding section. Desorption efficiency of the solvent should be determined before the analysis by spiking a known amount of the analyte into the sorbent tube or filter and then measuring the spike recovery. 

The research on persistent pesticides in the atmosphere has focused on the gas phase, particulate phase, rainfall, and pine needles. In China, there are only a limited number of studies on POP pesticides in the atmosphere, and these focus mainly on airborne particles. The spatial difference in concentration of persistent pesticides in air is small due to diffusion and transport. Since the agricultural ban on use in 1983, the concentration of POP pesticides in the atmosphere has decreased dramatically in China. In some regions, however, the concentrations of pesticide POPs in the atmosphere are unusually high, particularly for DDTs, which indicates that there might be new sources of POPs in these regions, such as Dicofol. In China, no environmental quality standards about pesticide POPs in the atmosphere have been established. 

Sediment is an important media for the transformation of POPs in the environment. Many years after production has ceased and the ban on the use of POP pesticides globally, research in other countries indicates that sediment has the highest concentrations of POP pesticides, as compared to soil, water, and air. Without emission sources of POP pesticides on land, sediment in some water bodies, especially inland lakes, became the source of POP pesticides in air and water. The recent research in China on sediments of inland lakes and costal areas has corroborated this finding. 

A variety of methods have been developed for sampling pesticides in air. Suitable procedures must deal with difficulties posed by the uncertainty regarding the physical state (aerosols, solid particles, vapors) of airborne residues, their relatively low concentrations (less than 1 mg/m, ca 80 ppb), fluctuations in pesticide concentrations and the levels of potential interferences with time, potential reactivity during the sampling process, and limited availability of sampling devices. These are in addition to the problems of cleanup, recovery, quantitation, and confirmation which are common to trace analytical processes once the sample has been collected and brought to the laboratory for determination. 

Barquet, A. Morgade, C. Shafik, T.M. Davies, J.E. Danauskas, J.X. Pesticides in Air Air monitoring studies in South Florida. Presented at 170th National Meeting of the American Chemical Society (PEST 089), Chicago, Aug. 24-9, 1975. 

Crosby, D.G. Moilanen, K.W. Seiber, J.N. Woodrow, J.E. Chemical reactions of pesticides in air. Presented at the American Chemical Society/Chemical Society of Japan Chemical Congress (PEST 053), Honolulu, April 1-6, 1979. 

While a -HCH is one of the most frequently studied chiral legacy pesticides in air and water, only limited measurements have been made of its enantiomers in soils and sediments, given its relatively low propensity to sorb to natural organic matter compared to other POPs (log Kg of 3.9 [32]). A depletion of (+)-a-HCH (EF = 0.39) was observed in surficial sediments of the North water Polynya [137]. This value was more nonracemic than the water column composition (EF = 0.45)[137],suggestingeitherpreferentialmicrobialdegradationof(+)-a-HCHasit descended in the water column [127] and/or further degradation once deposited in sediments. 

Yeary, R.A. and J.A. Leonard (1993). Measurement of pesticides in air during application to lawns, trees, and shrubs in urban environments, in Pesticides in Urban Environments, K.D. Racke and A.R. Leslie (Eds), ACS Symposium Series 522, American Chemical Society, Washington, DC, USA, pp. 275-281. 

Roinestadt et al. [40], analyzing 23 pesticides in indoor air and dust, reported that pesticides in air were always found in the corresponding dust with the exception of dichlorvos, o-phenylphenol and chlordane. The majority of household pesticides, however, are preferably detected in the home environment by dust sampling [40]. This holds true particularly for permethrin, which could not be detected in the air (detection limit 1 ng m ), whereas it was present in the dust samples in the milhgrams per kilogram range [40]. Stolz et al. [ 110] reporting results for permethrin in dust samples and air observed no correlation. 

In this review the use of indoor air and of house dust for identifying indoor contaminants and for characterizing the potential exposure were discussed. Furthermore a short overview of methods to analyze pesticides in air and dust as well as results was given. Results for indoor concentrations of pesticides may vary significantly with the conditions under which they are obtained. 

Wehner TA, Woodrow JE, Kim YH, et al. 1984. Multiresidue analysis of trace organic pesticides in air. Identification Analysis of Organic Pollutants 273-290. 

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