Exposure various pesticides

Obendorf, SK USDA Methods to limit worker exposure to various pesticides, including methyl parathion. 

Brouwer, D.H. and van Hemmen, J.J. (1994) Fitting personal protective equipment (PPE) to the hazard selection of PPE for various pesticide exposure scenarios in greenhouses, in Book of Abstracts of the American Industrial Hygiene Conference Exposition, American Industrial Hygiene Association, Anaheim, CA. 

The Food Quality Protection Act (FQPA) of 1996 mandated that the US EPA carry out risk assessments that consider the cumulative effects of exposure to pesticides having a common mechanism of toxicity, as well as consider exposure to each pesticide by various routes of exposure (e.g., dermal, dietary, inhalation) and sources (e.g., residues in food and water) in an aggregate manner [19]. To accomplish this, there needs to be sufficient evidence supporting a common adverse effect that is associated with a common mechanism of action in specific target tissues. To date, the required criteria necessary to establish a common mechanism of toxicity with a specific toxic effect for the pyrethroids are not available [1,8,98]. 

Hassoun et al. (1993) examined the effects of various pesticides on lipid peroxidation and DNA single strand breakage in the hepatic cells of female Sprague-Dawley rats. Animals were dosed orally once with endrin at 4.5 mg/kg, lindane at 30 mg/kg, chlordane at 120 mg/kg, or DDT (dichlorodiphenyl trichloro-ethane) at 40 mg/kg, or vehicle only (com oil, control). At 6, 12, and 24 hours post-dosing, 4 animals from each group were sacrificed, their livers removed, and prepared for lipid peroxidation assay. Lipid peroxidation was measured calorimetrically by determining the amount of thiobarbituric acid reactive substances (TBARS) formed. Exposure to endrin resulted in a 14.5% increase in hepatic mitochondrial... 

Inaeased risk of various cancers (e.g., lymphatics, blood, stomach, prostate, testes, brain, and soft tissues) was reported upon exposure to pesticides (Zahm and Blair 1993 Hayes et al. 1995 Zahm et al. 1997). Children s cancer, including brain tumors, leukemia, non-Hodgkin s lymphoma, sarcoma, and Wilms tumor due to direct or parental exposure to pesticides also has been determined (Fear et al. 1998 Kristensen et al. 1996 Pogoda and Preston-Martin 1997 Sharpe et al. 1995 Buckley et al. 1994). Often, the risk of cancer due to exposure to pesticides has been higher in children than in adults (Zahm and Ward 1998). Moreover, birth defects, including limb-reduction defects, have been linked to exposures to pesticides (Restrepo et al. 1990 Schwartz and LoGerfo 1998 Lin et al. 1994), as has a higher-than-normal risk of stillborn births (Pastore et al. 1997). 

The UK-POEM database is based on a review of the data available on the exposure of pesticide spray operators (in the UK). The review indicated that several factors determined the dose absorbed by a spray operator. These included the following the volume of external contamination, the extent to which this external contamination penetrated clothing to reach the skin and the rate at which the chemical came into direct contact with the skin surface and was absorbed (JMP, 1986 Martin, 1990). These various independent factors were assumed, with the exception of dermal absorption, to be of a sufficient generic nature to be suitable for extrapolation purposes. Two major work activities were differentiated mix-ing/loading and application. An update of the default values in UK-POEM has been presented (POEM, 1992). 

Users of agricultural pesticides perform many activities that involve direct exposure to these chemicals. Adequate PPE selection guidelines must address the range of pesticide-handling jobs and the associated exposure risks. To simplify and focus this discussion, the various pesticide activities will be described under three main operations mixing, loading, and application. 

In a case control study of NHL in Nebraska, Hoar Zahm et al (3 ) examined the association with exposure to various pesticides. A small Increase in NHL (OR-1.5 95% Cl 0.9-2.4) was associated with use of 2,4-D. The odds ratio increased to... 

Suicide (7511 patients, 66.7%) was the most common intent of exposure. The oral route (8930 patients, 79.2%) was the most common route of exposure. Table 8 shows increased age. suicide attempt, oral exposure, and concurrent exposure with a higher risk of fatality. In terms of age differences, people 19-39 years old comprised the largest number of injured patients. Acute pesticide poisoning mainly involved adults, and the mean age of patients was 43,3 18.9 years. Acute pesticide poisoning was associated with a very high case fatality rate (14.5%), and there was a wide range of differences in clinical severity among various pesticides. 

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. 

T IS GENERALLY RECOGNIZED that a potential health risk exists for agricultural workers (applicators, mixer-loaders, harvesters, and Held workers) who are exposed to pesticides. Thus, since 1980, various symposia, including the one upon which this book is based, have been held to examine various parameters involved in the risk assessment of these workers due to dermal exposure from pesticides. 

A chemical that is not corrosive but causes a reversible inflammatory effect on living tissue by chemical action at the site of contact. A chemical is considered a skin irritant if, when tested on the intact skin of albino rabbits by the methods of Consumer Products Safety Commission (CPSC) 16 CFR Part 1500.41 for an exposure of four or more hours or by other appropriate techniques, it results in an empirical score of 5 or more. A chemical is classified as an eye irritant if so determined under the procedure listed in CPSC 16 CFR Part 1500.42 or other approved techniques. Some examples of irritants are chlorine, nitric acid, and various pesticides. 

Komorova (1976) developed interesting data on certain blood diseases caused by exposure to organochlorine compounds. DDT and DDE contents were higher in the hemopoietic organs of people who died of leukoses or hypoplastic anemia than in their subcutaneous fat. Of 1,083 patients examined to identify the causes of various forms of leukoses, hypoplastic anemia and diatheses, 17.4% had a past history of prolonged exposure to pesticides (compared with 6% of people having other than hematologic diseases). 

Many very hazardous solvents, such as benzene and carbon tetrachloride, were widely used until the 1970s. The situation was very similar for the use of pesticides. Among the toxic pesticides that were still in wide use 20 years ago were chlorophenols, DDT, lindane, and arsenic salts, all of which are classified as human carcinogens as well as being acutely toxic. Fortunately, use of these kinds of very toxic chemicals is now limited in the industrialized world. However, because the number of chemicals used in various industries continues to increase, the risks of long-term health hazards due to long-term exposure to low concentrations of chemicals continues to be a problem in the workplace. 

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