Protective clothing assessment

A computer program is provided for ease of calculation and efficient use of the standard. This rational method of assessing hot environments allows identification of the relative importance of different components of the thermal environment, and hence can be used in environmental design. The WBGT index is an empirical index, and it cannot be used to analyze the influence of the individual parameters. The required sweat rate (SW. ) has this capability, but lack of data may make it difficult to estimate the benefits of protective clothing. 

Based on the patch method to assess worker or re-entry exposure, researchers have developed a database, which may be used to estimate exposure. Each patch from an individual in a study can be entered into the database separately, the residue data from patches from various body areas can be summed to yield a whole-body exposure number, and the data may be sorted as to worker tasks, equipment used, protective clothing worn, formulation types and other parameters. This is the basis for the currently used Pesticide Handlers Data Base (PHED), which was developed through a joint effort in the 1980s of CropLife America [formerly known as American Crop Protection Association (ACPA) and National Agricultural Chemicals Association (NACA)], the Environmental Protection Agency (ERA) and Health Canada. " The PHED is discussed in detail in another article in this book. 

In this part of the study, the internal dose of propoxur was assessed for HV applicators (n = 9) and harvesters (n = 18) using biological monitoring in two trials. In the first trial, workers wore their normal work clothing, followed by a trial where the same workers wore additional protective clothing. The minimum period between the two trials was 5 days. 

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. 

Fenske, R.A. (1988) Comparative assessment of protective clothing performance by measurement of dermal exposure during pesticide applications, Appl. Ind. Hygiene, 3 207-213. 

The outer layer of samples (gloves, coveralls, socks, face wash, hand wash, and hat) allowed measurement of the complete dose encountered on the outside of the protective clothing without any subsampling. This eliminated any uncertainty or error due to the highly variable deposition of residues across the body surface. This is the upper limit of the potential dose that could be encountered by the operator, and it is used to assess the effectiveness of the protective clothing and other preventive measures. 

Behnke and Seaman (35) have designed equipment which measures the conductive, convective, and radiant heat flux through textiles However, their instrumentation was designed for testing protective clothing to high temperature exposure and may not be useful for assessing thermal characteristics of textiles under normal end-use conditions. 

Fluorescent tracer techniques hold the promise of improved accuracy in assessing dermal exposures, as they require no assumptions regarding the distribution of exposure across skin surfaces. However, this approach also has several limitations. First, it requires introduction of the tracer compound into the agricultural spray mix. Secondly, there must be demonstration of a correspondence between pesticide deposition and deposition of the fluorescent compound for the production, such that the fluorescence can indeed be considered a tracer of chemical deposition. Thirdly, range-finding and quality assurance studies may be needed to ensure the accuracy of tracer measurements. Fourthly, when protective clothing is worn by workers, the relative penetration of the pesticide and tracer needs to be characterized. All of these limitations make fluorescent tracer methods technically challenging. 

Preliminary Assessment of Life-Cycle Costs of Protective Clothing US. Environmental Protection Agency, 1990. EPA/600/S2-90/021. 

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