Monitoring dermal exposure

In addition, the use of chemical protective clothing was not supported by air or surface contamination monitoring to determine the potential for dermal exposure and the appropriate PPE. 

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. 

In order to evaluate "within-worker" variances of dermal exposure and its distribution over the body, whole-body monitoring during three applications and concomitant re-entry was performed for high-volume (HV) applicators (n = 4) and harvesters of carnations (n = 6). 

Dermal exposure assessment Whole-body monitoring... 

The WBDs retained an average potential dermal exposure (PDE) of 13,757 pg chlorpyrifos. If clothing penetration is assumed to be 10% and dermal absorption 9.6% per 24 hr, then the absorbed dose would be 132 pg, and the absorbed dosage would be about 1.9 pg/kg. Biological monitoring of the 13 volunteers wearing cotton dosimeters indicated that the absorbed daily dose that penetrated the WBD and was absorbed was 2 pg chlorpyrifos equivalents/kg (Table 2). 

The first pesticide exposure study was reported by Griffiths et al. (1951). Parathion was trapped on respirator filter discs during application to citrus trees. Batchelor and Walker (1954) expanded exposure monitoring to include the estimation of potential dermal exposure using pads attached to workers clothing. Durham and Wolfe (1962), in their classic review of worker exposure methodologies, also provided some experimental validation for the best available methods. 

Well-conducted studies in animals to evaluate these end points for mirex following acute- and intermediate-duration inhalation, oral, and dermal exposures would be helpful. As with the shorter duration exposures, monitoring humans who are chronically exposed to mirex by any route would be useful. 

Phenol has been measured in effluents (up to 53 ppm), ambient water (from 1.5 to >100 ppb), drinking water (not quantified), groundwater (from 1.9 to >10 ppb), rain (0.075-1.2 ppb), sediment (>10 ppb), and ambient air (0.03-44 ppb). Occupational exposures occur through inhalation and dermal exposure air concentrations monitored in various workplaces range from 0.1 to 12.5 mg/m3 (0.03-32 ppm). Occupational as well as consumer exposure may also occur through dermal contact with phenol or phenol-containing products. 

No studies were located regarding the dermal absorption of 1,2-dibromoethane in humans. However, two occupational case reports suggest that dermal absorption of 1,2-dibromoethane was the major route of exposure to 1,2-dibromoethane that resulted in death (Letz et al. 1984). Dermal absorption does occur in animals but has not been quantified. Absorption of 1,2-dibromoethane was demonstrated in guinea pigs whose blood levels were monitored during dermal exposure to 1 mL of... 

Reproductive Effects. It has not been definitively determined whether chloroform exposure induces reproductive effects in humans. No studies were located regarding reproductive effects in humans after inhalation or dermal exposure to chloroform. Only one study was located regarding reproductive effects in humans after oral exposure to chloroform. Bove et al. (1995) studied the effects of drinking-water consumption on birth outcomes and found that exposure to TTHM at levels >0.1 ppm resulted in reduced birth weight and size as well as an increased risk of oral cleft, central nervous system, and neural tube defects. These results should be viewed with caution since the authors did not specifically monitor chloroform levels. The effects seen may be due to exposure to other THMs or non-THM contaminants in the drinking water. 

If 1,2-diphenylhydrazine or its metabolites in urine can be correlated with dermal exposure in humans, it may be possible to monitor humans for exposure. If toxic effects resulting from dermal exposure to 1,2-diphenylhydrazine are identified in humans, it may then be possible to correlate urinary levels of 1,2-diphenylhydrazine or a metabolite with systemic effects. 

In this study a series of surface water and deep soil samples were analyzed to detect ai migration or runoff of waste pesticides from typical Chemical Control Centers. Entomological evaluation of soil biota and monitoring of dermal exposure to pesticides of mlxer-appllcators took place throughout the 1980 season. No adverse effects as a result of the Chemical Control Centers were detected. 

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( ). 

In addition to its presence in the ambient atmosphere, diazinon also has been monitored in both outdoor and indoor air associated with its use in a variety of domestic, commercial, and occupational exposure situations. Exposure to diazinon from its use in lawn and home garden applications was evaluated by Davis et al. (1983). Diazinon was mixed with water and sprayed using compressed air sprayers or hose-end sprayers, and potential respiratory and dermal exposures were estimated from residues collected from respirator filters, body pads, and hand rinsings. These authors reported mean respiratory exposures of 1.9,... 

Table 1 shows the number and types of workers and the various situations in which these workers were monitored for dermal exposure to carbaryl. Formulations of carbaryl that were evaluated included 80S, a wettable powder containing 80% active carbaryl 50W, a wettable powder containing 50% active carbaryl Sevimol 4, a liquid suspension of carbaryl in molasses containing 40% active ingredient and XLR, a water based flowable containing 4 lbs active carbaryl per gallon. 

Table I.—Operations in which workers were monitored for dermal exposure to carbaryl.

White Phosphorus Smoke. There is a limited amount of available information on human toxicity of white phosphoms smoke. These acute-duration human exposure studies monitored for systemic effects following inhalation exposure. Death, systemic effects, and developmental effects have been observed in animals exposed to airborne white phosphoms smoke for acute and intermediate durations. Reproductive and neurological end points have also been monitored following intermediate-duration inhalation exposure. No dermal exposure studies were located. 

The collection and handling techniques for monitoring 2,4-D exposure levels in the breathing zone, on patches to measure dermal exposure, and in urine were similar to the procedures carried out in the 2,4,5-T tests. One difference was in the type and location of patches used. Denim strips were attached to workers clothing near bare skin areas. A 2.5 by 40-cm strip was attached to the workers collar, a 2.5 by 48-cm strip to the hatband, and two 2.5 by 15-cm strips around the wrists to the cuff. 

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