Exposure analysis pesticides

Golt, J. S., J. Lubin, et al. (2004). Gomparison of pesticide levels in carpet dust and self-reported pest treatment practices in four US sites. Journal of Exposure Analysis and Environmental Epidemiology 14(1) 74-83. 

While deterministic methods are still quite useful in determining long-term, chronic exposures to pesticides, they are being replaced with probabilistic methods for the analysis of acute (short-term) exposures. These probabilistic methods take advantage of improvements in computational capabilities. 

Harden, L., Eriksson, M. Dcgcrmann, A. (1995) Meta-analysis of four Swedish case-control studies on exposure to pesticides as risk-factor for soft-tissue sarcoma including the relation to tumour localization and histopathological type. Int. J. Oncol., 6, 847-851... 

The committee recommends the inclusion of a detailed and accurate exposure analysis for a subset of the biomonitored population in large-scale biomonitoring studies that includes analyses of environmental media in the residence and uses a survey instrument to obtain information on diet, consumer product use, occupational exposures, and other factors relevant to the chemical exposure pathways that are being examined. The exposure assessment can be patterned on protocols used in other exposure analyses, such as the National Human Exposure Assessment Survey (NHEXAS), the Minnesota Children s Pesticide Exposure Study, and Children s Total Exposure to Pesticides and Other Persistent Organic Pollutants. 

Yoder J, Watson M, Benson WW. 1973. Lymphocyte chromosome analysis of agricultural workers during extensive occupational exposure to pesticides. Mutat Res 21 335-340. 

The purpose of this paper is to describe flie policies and procedures of dietary exposure analysis and risk assessment in these two portions of die world, to highlight their differences, and to demonstrate how they both aim for the same goal, a safe food supply. Unless otherwise noted, all references to exposure in this paper pertain to the intake of pesticide residues in food. Nomenclature in other parts of the world refers to dietary intake, but the general concept is the same, regardless of the terminology. Likewise, all references to risk and risk assessment pertain to the risk assessment with regard to dietary exposure to pesticide residues. 

Two types of dietary exposure are understood. Chronic exposure represents exposure to pesticide residues in food over a relatively extended time period, frequently assumed to be the course of a lifetime. In contrast, acute exposure represents exposure to pesticide residues in food over a relatively short time period, usually over the course of one day. Most of the significant differences between the EU and US approaches to dietary exposure analysis and risk assessment focus on acute dietary exposure. Some of the differences have their sources in the different types of data available in the two areas. Other differences have their sources in different regulatory policies or societal viewpoints. 

Pesticide laboratories of food industries and regulatory agencies are continually faced with the problem of analyzing samples whose history of exposure to pesticides is unknown. More than one pesticide may be present in any of these samples and the residue of each may have to be determined. To help solve this problem of analyzing diverse sample types for exposure to different types of pesticides, effort has been made by the FDA scientists, among others, to develop methods for the multiple analysis of pesticides. 

Although the benefits of pesticides are undeniable, attention in recent years has been focused on their impact on human health and environment. Although pesticide law requires that both risks and benefits be considered in all decisions, risk drives the process in terms of depth of analysis and allocation of federal resources. Two questions relative to risk are appropriate "What is acceptable risk " and "How can we minimize the risk . No amount of research can eliminate all uncertainties associated with assessing the risks of exposure to pesticides or eliminate the controversial judgments inherent in any decision about control of pesticide exposures. 

In contrast to these problems, evidence of exposure to pesticides is often much more readily available by analysis of excreta, body fluids and expired air ( ). The power of modern analytical procedures, a topic to be addressed later in this Conference, is exemplified by the characterization of 115 organic compounds in samples of breath from 54 subjects ( ). Exhaled ethane and n-pentane in mice, rats and monkeys (45) has proved to be a useful index of lipid peroxidation, these gases being derived from 0)3-and u)6-fatty acid hydroperoxides (12, 13). Non-invasive measures of drug metabolizing capacity have been developed, using C-phenacetin or C-aminopyrine hepatic dysfunction can be assessed in an analogous manner (, 49). On the horizon is the... 

Risk-benefit analysis as related to pesticides will be discussed from the following points of view (1) how does one determine risk, (2) what are the potential adverse health effects in man from exposure to pesticides, (it must be recognized that adverse effects of pesticides on wildlife and non-target organisms are also an important part of risk-benefit analysis. However, because of time limitations we will restrict our consideration to adverse health effects in man), (3) principles and problems concerning the estimation of risk to man from exposure to pesticides and (4) effects of pesticides that are considered to be beneficial. 

Two general types of methods are available for estimating human exposure to pesticides. First, direct entrapment methods involve the use of some mechanism to entrap the toxic material as it comes in contact with the person during an exposure period. The amount of entrapped toxicant, as determined by chemical analysis, is then a direct measure of the particular exposure under study. Further calculations using the kinetics of dermal absorption for the compound and formulation under study are required to arrive at the actual ateorbed dose. For the oral and inhalation routes, exposure and absorbed dose are more closely equivalent than for the dermal route. However, for precise data, absorption must be taken into account for these routes, also. Second, indirect methods are based on measurement of some effect of the compound on the exposed individual (such as blood... 

Assessment of worker exposure to pesticides through field studies requires collection devices placed on or near the worker, extraction techniques, quantification of the chemical, and statistical analysis. We present an overview of these methods with specific attention given to dermal absorption pads, their proper placement at various body locations, and the statistical variability in pad contamination which commonly results. Use of personal air samplers is reviewed. 

The feasibility of employing fluorescent tracers and video imaging analysis to quantify dermal exposure to pesticide applicators has been demonstrated under realistic field conditions. Six workers loaded a tracer with the organophosphate pesticide, diazinon, into air blast sprayers, and conducted normal dormant spraying in pear orchards. They were examined prior to and immediately after the application. UV-A illumination produced fluorescence on the skin surface, and the pattern of exposure was digitized with a video imaging system. Quantifiable levels of tracer were detected beneath cotton coveralls on five workers. The distribution of exposure over the body surface varied widely due to differences in protective clothing use, work practices and environmental conditions. This assessment method produced exposure values at variance with those calculated by the traditional patch technique. 

Analytical methods have been developed by the Southwest Research Institute, Battelle-Columbus, and others for analyzing pesticides, PAHs, and PCBs in many environmental matrices, including indoor air and house dust samples (Camann 1994 Chuang et al. 1994). Progress in sampling and analysis make possible improvements in exposure analysis and the epidemiological studies discussed in the following sections. 

Camann DE, Buckley JD (1994) Carpet dust an indicator of exposure at home to pesticides, PAHs, and tobacco smoke. In Proceedings of the 6th Conference of the International Society of Environmental Epidemiology and 4th Conference of the International Society for Exposure Analysis, Research Triangle Park, NC. 

Shafik TM, Bradway DE, Enos HR, et al. 1973a. Human exposure to organophosphorus pesticides A modified procedure for the gas-liquid chromatographic analysis of alkylphosphate metabolites in urine. J Agr Food Chem 21 625-629. 

Endosulfan is a popular pesticide with greenhouse chrysanthemum producers. Surveys of usage patterns and potential exposure were conducted in Ontario (Archibald et al. 1994b). Collection and analysis of a-and P-endosulfan and endosulfan sulfate in greenhouse air have been described (Vidal et al. 1997). Results indicate that 7.5% of the initial concentration of endosulfan remained in the greenhouse atmosphere 24 hours after application. 

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