Mixers potential exposure

Nigg and Stamper (1983) conducted potential exposure and actual exposure measurements during three weekdays over three consecutive weeks for applicators and mixer-loaders, one week using normal work clothes, the second week disposable coveralls in addition to their work clothes, and the third week disposable coveralls and NIOSH-approved respirators. In conjunction, urinary excretion of a metabolite of the active ingredient was... 

The design of a study by Davies et al. (1982) for mixers and applicators was similar to that of Nigg and Stamper (1983). "Between-days" variances of exposure were not given. Mean urinary metabolite concentrations were used to show reduction of internal exposure by protective clothing. The design of the study by van Rooij et al. (1993) was similar to our study (i.e., "within-worker" comparisons of internal exposure). Because no potential dermal exposure was assessed in this study, "within-worker" variances of potential exposure are not known. 

Pesticide usage factors include those factors needed to characterize the amount of pesticide an individual is potentially exposed to each day, as well as the duration, frequency and interval of potential exposures. For example, for mixer/loaders/ applicators, this would include hectares typically treated per day, typical application rates, types of equipment used, and whether application is conducted by the farmer or a custom applicator. 

Mixers receive most of their exposure as a result of splashes, powder spills, contact with encrusted equipment, overflows, and other random events. None of these are predictable, yet the magnitude of these potential exposures obliterates the long term contribution of vapors, low level dust clouds, etc., when statistical correlations are made. Consequently, the most practical approach would be to revamp the mixing process so that the opportunities for accidents are minimized, recognizing that this short time-span operation should be conducted under strict protective conditions. 

C. Conrad, D. Cooper, C. Monitoring of Potential Exposures of Mixer-Loaders, Pilots, and Flaggers During Application of tributyl phosphorotrlthloate (DEF) and trlbutyl phosphorotrithl-olte (FOLEX) to Cotton Fields in the San Joaquin Valley of California in 1979. California Department of Food and Agriculture, 1981. 

Applicators, mixers, loaders, and others who mix, spray, or apply pesticides to crops face potential dermal and/or inhalation exposure when handling bulk quantities of the formulated active ingredients. Although the exposure periods are short and occur only a few times annually, an estimate of this exposure can be obtained by quantifying the excreted polar urinary metabolites. Atrazine is the most studied triazine for potential human exposure purposes, and, therefore, most of the reported methods address the determination of atrazine or atrazine and its metabolites in urine. To a lesser extent, methods are also reported for the analysis of atrazine in blood plasma and serum. 

The calculation of potential total dermal exposure of mixer-loaders and re-entry workers using dosimetry data and calculation of the internal dose using biological monitoring data is complex but will be discussed briefly. 

Pesticide mixers and applicators at Farms A and B, and also at an active farm not having a CCC, were monitored for topical (dermal) exposure throughout the 1980 season. No Increased exposure was measured as a result of using the Chemical Control Centers. A paper addressing potential applicator exposure In this and similar situations Is In preparatlon( ). 

Potential routes of exposure to molinate include inhalation (for mixers, applicators, field workers, and residents of rice-growing regions), dermal (for mixers, applicators, field workers, and anyone exposed to drift of spray droplets or residues on plants), and dietary (from drinking water sources contaminated with molinate and from residues on rice and rice products). 

May displace chemicals that pose potential human health concerns or reduce exposures to mixers, loaders, applicators, and reentry workers... 

California regulations require daily provision and use of clean coveralls or other clean outer clothing to mixers, loaders, flaggers, and applicators of any pesticide in toxicity Categories I and II (12). These requirements serve to reduce the potential dermal exposure of workers to pesticides by decreasing the area of bare skin available for contact with the chemicals. 

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. 

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