Pesticide measuring exposure

The purpose of this article is to present a detailed description of the current field methods for collection of samples while measuring exposure of pesticides to farm workers. These current field methods encompass detailed descriptions of the methods for measuring respiratory and also dermal exposure for workers who handle the pesticide products directly (mixer-loaders and applicators) and for re-entry workers who are exposed to pesticide dislodgeable residues when re-entering treated crops. 

Table 26.5 Acute and Chronic Toxicity of Pesticides Measured from Laboratory Exposures of Fish Species...

PRINCIPLES OF OPERATOR EXPOSURE MODELLING 175 PHED PESTICIDE HANDLERS EXPOSURE DATABASE 176 General Description 176 Qnality of Data 177 Formnlations and Use Scenarios 177 Use in Risk Assessment 178 Exposnre Rednction Measures 178 Model Updates 179 Comments on the Model 179 GERMAN MODEL 180 General Description 180 Formulations and Use Scenarios 181 Use in Risk Assessment 182 Exposure Reduction Measures 182 Model Updates 182 Comments on the Model 183... 

Curry and Iyengar (1992) have reviewed and compared existing published and unpublished guidance for measuring exposure of individuals using pesticides or... 

Considering the multi-route and multimedia exposure of pesticides, the exposure assessment can be considered from three aspects (i) external (or potential) dose, (ii) internal or absorbed dose and (iii) biologically active dose. The external dose measurements determine the potential exposure of individuals or population. It involves a proper monitoring of the exposed environment, including air, water, food consumptions and workplace environment, to achieve an accurate quantification of the potential exposure of individuals. This kind of monitoring does not give information about the absorption of pesticides into the body. 

Although the extent of absorption was not measured, the above evidence suggests that absorption in humans occurs rapidly following dermal exposure to commercial pesticide formulations of methyl parathion. 

Davies JE, Peterson JC. 1997. Surveillance of occupational, accidental, and incidental exposure to organophosphate pesticides using urine alkyl phosphate and phenolic metabolite measurements. Aim NY Acad Sci 837 257-268. 

Durham WF, Wolfe HR. 1962. Measurement of the exposure of workers to pesticides. Bull WHO 26 75-91. 

Shafik TM, Sullivan HC, Enos HR. 1973b. Multiresidue procedure for halo- and nitrophenols. Measurement of exposure to biodegradable pesticides yielding these compounds as metabolites. J Agr Food Chem 21 295-297. 

Agarwal et al. 1978), the quantification of these specific enzymes may indicate that exposure to endosulfan has occurred. Blood tests, such as decay curves for aminopyrine in plasma, which are semiquantitative indices of liver enzyme induction, have been used successfully in the past to demonstrate enzyme induction in pesticide-exposed workers. Because numerous chemicals found at hazardous waste sites also induce these hepatic enzymes, these measurements are not specific for endosulfan exposure. However, measurements of enzyme activity, together with the detection of the parent compound or its metabolites in tissue or excreta, can be useful indicators of exposure. All of these potential biomarkers require further verification in epidemiological studies. Further studies with focus on the development of methods to separate and measure the estrogenicity of endosulfan in in vitro assays would be valuable since these assays are more sensitive and discriminative than other conventional biomarkers. Preliminary results have been presented by Sonnenschein et al. (1995). 

Plant uptake is one of several routes by which an organic contaminant can enter man s food chain. The amount of uptake depends on plant species, concentration, depth of placement, soil type, temperature, moisture, and many other parameters. Translocation of the absorbed material into various plant parts will determine the degree of man s exposure—i.e., whether the material moves to an edible portion of the plant. Past experience with nonpolar chlorinated pesticides suggested optimal uptake conditions are achieved when the chemical is placed in a soil with low adsorptive capacity e.g., a sand), evenly distributed throughout the soil profile, and with oil producing plants. Plant experiments were conducted with one set of parameters that would be optimal for uptake and translocation. The uptake of two dioxins and one phenol (2,4-dichlorophenol (DCP)) from one soil was measured in soybean and oats (7). The application rates were DCP = 0.07 ppm, DCDD 0.10 ppm, and TCDD = 0.06 ppm. The specific activity of the com-... 

For most chemicals, inhalation is the main route of entry into the body. However, certain chemicals (e.g. phenol, aniline, certain pesticides) can penetrate intact skin and so become absorbed into the body. This may occur through local contamination, e.g. from a liquid splash, or through exposure to high vapour concentrations. Special precautions to avoid skin contact are required with these chemicals and potential exposure via skin absorption has to be taken into account when assessing the adequacy of control measures. Chemicals able to penetrate intact skin are listed in Table 4.2. 

C.P. Weisskopf and J.N. Seiber, New approaches to the analysis of organophosphate metabolites in the urine of field workers, in ACS Symposium Series Biological Monitoring for Pesticide Exposure Measurement, Estimation, and Risk Reduction, eds. R.G.M. Wang, C.A. Franklin, R.C. Honeycutt, and J.C. Reinert, American Chemical Society, Washington, DC, pp. 206-214 (1989). 

---