Dermal Exposure Levels Research Articles

Case Study on Risk Evaluation of Silver Nanoparticle Exposure from Antibacterial Sprays Containing Silver Nanoparticles

This study evaluated the risk of silver nanoparticle (AgNP) exposure from antibacterial sprays containing AgNPs. Using an exposure simulation chamber as the setting for the experiment, various instruments, including a scanning mobility particle sizer (SMPS), condensation particle counter (CPC), dust monitor, and mixed cellulose esters (MCE) filters, are connected to the chamber to measure the exposure levels of AgNPs when using the sprays. To assess potential risks to consumers, margin of exposure (MOE) approach was used to assess risk in which a calculated MOE was compared with a target MOE. When evaluating the risk of antibacterial sprays to inhalation exposure using the MOE, spraying a whole can and spraying an air conditioner both resulted in a high‐risk concern level with a MOE ranging from 59 to 146 that was much lower than the no‐risk concern level of 1000, while some spray showed a MOE 2049 with no‐risk concern level. The dermal exposure levels with a single layer of clothing were estimated at 2–50 μg/kg/day with a MOE ranging from 20,000 to 500,000. Therefore, the current results showed the possibility of high‐risk inhalation exposure to AgNPs released when using antibacterial sprays.

Leukemia from Dermal Exposure to Cyclophosphamide among Nurses in the Netherlands: Quantitative Assessment of the Risk

Several studies showed that oncology nurses are exposed to antineoplastic drugs via the skin during daily activities. Several antineoplastic drugs (including cyclophosphamide) have been classified as carcinogenic to humans. This study aims to assess the leukemia risk of occupational exposure to cyclophosphamide. Average task frequencies from the population of oncology nurses in the Netherlands and task-based dermal exposure intensities were used to calculate oncology nurses' dermal exposure levels. A dermal absorption model in combination with a physiologically based pharmacokinetic model was used to assess the delivered dose of cyclophosphamide and its active metabolites in the bone marrow. This delivered dose was subsequently related to pharmacodynamic and epidemiological information from a longitudinal study with cyclophosphamide-treated patients to estimate the excess lifetime leukemia risk at age 80 for Dutch oncology nurses after 40 years of exposure to cyclophosphamide. The excess lifetime leukemia risk at age 80 of an exposed oncology nurse after 40 years of dermal exposure to cyclophosphamide was estimated to be 1.04 per million oncology nurses. This risk could potentially increase to a maximum of 154 per million if a nurse performs all cyclophosphamide-related tasks with the maximum frequency (as observed in this population) and is exposed to maximum exposure intensities for each task without using protective gloves for 40 years. This study indicates that the risk of an oncology nurse in a Dutch hospital with an average dermal exposure to cyclophosphamide is well below the maximum tolerable risk of one extra death from cancer per 250 deaths after 40 years of occupational exposure, and that this level is not exceeded in a worst-case scenario.

Dermal & inhalation exposure of operators during fungicide application in vineyards. Evaluation of coverall performance

In the present study the dermal and the inhalation exposure of five operators during fungicide applications in vineyards were determined. The produced exposure datasets can be used as surrogate for the estimation of the actual and the potential dermal as well as inhalation operator exposure levels for this application scenario. The dermal exposure was measured using the whole body dosimetry method while the inhalation exposure with the use of personal air sampling devices with XAD tubes located on the operator's breathing zone. Ten field trials were carried out by 5 different operators using a tractor assisted hand-held lance with spray gun at the Tanagra region of Viotia, Greece. An in-house GC–ECD analytical method was developed and validated for the determination of penconazole, which was the active substance (a.s.) of the fungicide formulation used in field trials. The mean recovery of field-fortified samples was 81%. The operator exposure results showed expected variability and were compared to those derived from the German model for prediction of operator exposure. The comparison of the 75th percentile values for an operator wearing personal protection equipment has shown that the measured levels were 2.2 times lower than those estimated by the German model. The levels of actual dermal exposure ranged from 2 to 19mg/kg a.s. applied. The protection provided by the two types of coveralls was evaluated and in comparison to the existing reduction factors used for other types of PPE (coveralls) was found satisfactory for the operator under the conditions of the specific applications.

Relationship between dermal exposure and PAH-DNA adducts in lymphocyte DNA in truck-drivers exposed to polycyclic aromatic hydrocarbons

Background: Truck drivers in Pakistan are confronted with numerous respiratory problems mainly because no proper occupational safety guidelines exist and health monitoring services are rarely extended to them. Aim: We aimed to assess dermal contamination by Polycyclic Aromatic Hydrocarbons (PAHs) among 79 truck drivers who work for more than six hours per day. Methods: We took both skin pad and urine samples to measure dermal exposure by PAH and subsequent secretion through body. Pyrene was used as biological marker for dermal exposure. Results: The results show that truck drivers have high PAH dermal exposure. However, the mean pyrene exposure levels were reduced to 33% when painters wore masks during work. The biological measure for the internal exposure to PAHs was urinary 1-hydroxyprene whose concentration was relatively low (range 21 and 133 nmol) when compared to dermal exposure levels. PAH-DNA adducts were observed in lymphocytes DNA among one-third of the workers. Using multiple regression analysis, we identified mass balance between dermal pyrene dose and 1-hydroxyprene excretion that confirmed the relevance of the dermal exposure route. Our estimates of the dermal and urinary pyrene levels clearly indicate that an average of 52% of the total absorbed amount of pyrene enters the body through the skin. Conclusions: Study concludes that mitigation measures to reduce PAH exposure should be focused more on the reduction of dermal contamination by PAHs than any other route. Moreover, use of occupational safety guideline must be prepared and distributed among truck drivers.

Sub-chronic Dermal Toxicity of Silver Nanoparticles in Guinea Pig: Special Emphasis to Heart, Bone and Kidney Toxicities.

Silver nanoparticles (Ag NPs) have been widely used as new potent antimicrobial agents in cosmetic and hygienic products. Present study compares the tissue levels of Ag NPs in different organs of Guiana Pigs quantitatively after dermal application and analysis the morphological changes and pathological abnormalities on the basis of the Ag NPs tissue levels. Before toxicological assessments,the size of colloidal nanosilver was recorded by X-Ray Diffraction and Transmission Electron Microscope tests and the sizes of samples were recorded in sizes less than 100 nm. For toxicological evaluation, male guinea pigs were exposed to three concentrations of Ag NPs (100, 1000 and 10000 ppm) according to acute pretests for further assessments in subchronic model in a period of 13 weeks . A close correlation between dermal exposure and tissue levels of Ag NPs was found (p < 0.05) and tissue uptakes happened in dose dependent manner with the following ranking: ki dney>muscle>bone>skin>liver>heart >spleen. In histopathological studies, severe proximal convoluted tubule degeneration and distal convoluted tubule were seen in the kidneys of the middle and high-dose animals. Separated lines and marrow space narrow were determined as two major signs of bone toxicities which observed in three different dose levels of Ag NPs. Increased dermal dose of Ag NPs caused cardiocyte deformity, congestion and inflammation. The three different Ag NPs concentration gave comparable results for several endpoints measured in heart, bone and kidney, but differed in tissue concentrations and the extent of histopathological changes. It seems that Ag ions could be detected in different organs after dermal exposure ,which has the potential to provide target organ toxicities in a time and dose dependent manner.

Dermal exposure assessment of pesticide use: The case of sprayers in potato farms in the Colombian highlands

Quantifying dermal exposure to pesticides in farming systems in developing countries is of special interest for the estimation of potential health risks, especially when there is a lack of occupational hygiene regulations. In this paper we present the results of a dermal exposure assessment for the potato farming system in the highlands of Colombia, where farmers apply pesticides with hand pressure sprayers without any personal protective equipment. The fractioning of the pesticide, in terms of potential and actual dermal exposure, was determined via the whole-body dosimetry methodology, using the tracer uranine as pesticide surrogate, and luminescence spectrometry as analytical method. We assessed the three activities involved in pesticide management: preparation, application, and cleaning; analyzed three types of nozzles: one with a standard discharge and two modified by farmers to increase the discharge; and derived the protection factor given by work clothing. Our results suggest that to reduce the health risk, three aspects have to be considered: (i) avoiding the modification of nozzles, which affects the droplet size spectrum and increases the level of dermal exposure; (ii) using adequate work clothing made of thick fabrics, especially on the upper body parts; and (iii) cleaning properly the tank sprayer before the application activity.

Physiologically based toxicokinetic modelling as a tool to support risk assessment: three case studies.

In this contribution we present three case studies of physiologically based toxicokinetic (PBTK) modelling in regulatory risk assessment. (1) Age-dependent lower enzyme expression in the newborn leads to bisphenol A (BPA) blood levels which are near the levels of the tolerated daily intake (TDI) at the oral exposure as calculated by EFSA. (2) Dermal exposure of BPA by receipts, car park tickets, and so forth, contribute to the exposure towards BPA. However, at the present levels of dermal exposure there is no risk for the adult. (3) Dermal exposure towards coumarin via cosmetic products leads to external exposures of two-fold the TDI. PBTK modeling helped to identify liver peak concentration as the metric for liver toxicity. After dermal exposure of twice the TDI, the liver peak concentration was lower than that present after oral exposure with the TDI dose. In the presented cases, PBTK modeling was useful to reach scientifically sound regulatory decisions.

The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+−) genotypes were associated with a decrease in urine naphthalene level (p < 0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure.

Assessment of dermal exposure to N’N-dimethyl formamide in synthetic leather workers

Objective To assess the dermal exposure levels of N'N-dimethylformamide (DMF) in synthetic leather workers. Methods Potential dermal exposure levels of DMF was measured with skin wiping and hand washing samples in printing workers. The DMF concentration in personal air samples and urinary NMF were also detected. Results DMF was detected in all the hand washing (0.35～15.34 mg DMF) and skin wiping (29.58～110.45 μg DMF) samples. DMF level in hand washing samples and cumulative exposure level were correlated with NMF level in urine after logarithm transform. There was no good correlation between the DMF level of skin wiping samples and the urinary NMF level. Conclusion The sampling method of hand washing is a reasonable method to determine dermal exposure level. Key words: Dimethylformamide; Risk assessment; Environmental monitoring

Estimation of dermal and oral exposure of children to scented toys: Analysis of the migration of fragrance allergens by dynamic headspace GC–MS

Fragrances capable of inducing contact allergy in skin potentially can migrate from the toy to the child via oral or dermal contacts. The goal of this work was the developing of an analytical method based on dynamic headspace GC-MS to determine the concentration of 24 fragrances in saliva or sweat simulant. Under optimized conditions, 5 mL of the migration simulant with 2 g sodium chloride were incubated for 10 min at 30°C. The headspace was purged at a flow rate of 50 mL/min. The compounds were quantified by internal calibration resulting in good linearity (>0.991). The recovery was greater than 66.3% for most of the compounds. The limits of detection ranged between 0.5 ng/mL for hydrophobic and 196.0 ng/mL for hydrophilic fragrances. The method was subsequently applied to seven real toys purchased from the market. The highest migration rate could be observed for benzyl benzoate with 268.0 ng/cm(2)/min. Based on the migration data measured, the ranges of dermal and oral exposure of children to fragrances in scented toys were calculated. The maximum oral and dermal exposure levels were estimated at 22.2 μg per kg body weight (BW) and day (d) for benzyl benzoate and 605.0 μg/kg BW/d for benzyl alcohol, respectively.

Pesticide risk assessment: A study on inhalation and dermal exposure to 2,4-D and paraquat among Malaysian paddy farmers

A cross-section analytical study was conducted to evaluate the risk of pesticide exposure to those applying the Class II pesticides 2,4-D and paraquat in the paddy-growing areas of Kerian, Perak, Malaysia. It investigated the influence of weather on exposure as well as documented health problems commonly related to pesticide exposure. Potential inhalation and dermal exposure for 140 paddy farmers (handlers of pesticides) were assessed. Results showed that while temperature and humidity affected exposure, windspeed had the strongest impact on pesticide exposure via inhalation. However, the degree of exposure to both herbicides via inhalation was below the permissible exposure limits set by United States National Institute of Occupational Safety and Health (NIOSH). Dermal Exposure Assessment Method (DREAM) readings showed that dermal exposure with manual spraying ranged from moderate to high. With motorized sprayers, however, the level of dermal exposure ranged from low to moderate. Dermal exposure was significantly negatively correlated with the usage of protective clothing. Various types of deleterious health effects were detected among users of manual knapsack sprayers. Long-term spraying activities were positively correlated with increasing levels of the gamma-glutamyl transpeptidase (GGT) liver enzyme. The type of spraying equipment, usage of proper protective clothing and adherence to correct spraying practices were found to be the most important factors influencing the degree of pesticide exposure among those applying pesticides.

An Assessment of Dermal Exposure to Heavy Fuel Oil (HFO) in Occupational Settings

Heavy fuel oil (HFO) components are a group of heavy petroleum streams produced in oil refineries from crude oil. Due to its physicochemical properties, the dermal route is an important route of exposure. However, no information on dermal exposure levels for HFO has previously been published. A method for measuring dermal HFO levels was developed using wipe sampling and measuring phenanthrene and naphthalene as markers of HFO exposure. Measurement surveys were carried out in four different types of facilities: oil refineries, distribution terminals, energy providers, and an engine building and repair company. Dermal wipe samples were collected from different anatomical regions: neck, hands, and forearms. The frequency of tasks with potential for dermal HFO exposure was generally low at these facilities, with the exception of the distribution terminals and the engine building and repair site. The geometric mean (GM) dermal load on the hands was ∼0.1 μg cm(-2) for both left and right hand and 0.013 and 0.019 μg cm(-2) for the left and right forearm, respectively. With one exception, all results from the neck samples were below the limit of detection. The highest dermal loads for the hands and forearms were found in the engine building and repair facility (hands: GM = 1.6 μg cm(-2); forearms: GM = 0.41 μg cm(-2)). The tasks with the highest dermal loads were the maintenance (hands: GM = 1.7 μg cm(-2)) and cleaning tasks (hands: GM = 0.24 μg cm(-2)). Actual dermal loads were low when compared with workplace dermal exposure measurements reported by other researchers for similar scenarios with other substances. This may be explained by high compliance of gloves use by workers during HFO handling tasks and likely avoidance of contact with HFO due to its high viscosity and the requirement to keep HFO at elevated temperatures during storage, transport, and use.

Urine 1,6-Hexamethylene Diamine (HDA) Levels Among Workers Exposed to 1,6-Hexamethylene Diisocyanate (HDI)

Urinary 1,6-hexamethylene diamine (HDA) may serve as a biomarker for systemic exposure to 1,6-hexamethylene diisocyanate (HDI) in occupationally exposed populations. However, the quantitative relationships between dermal and inhalation exposure to HDI and urine HDA levels have not been established. We measured acid-hydrolyzed urine HDA levels along with dermal and breathing-zone levels of HDI in 48 automotive spray painters. These measurements were conducted over the course of an entire workday for up to three separate workdays that were spaced approximately 1 month apart. One urine sample was collected before the start of work with HDI-containing paints and subsequent samples were collected during the workday. HDA levels varied throughout the day and ranged from nondetectable to 65.9 microg l(-1) with a geometric mean and geometric standard deviation of 0.10 microg l(-1) +/- 6.68. Dermal exposure and inhalation exposure levels, adjusted for the type of respirator worn, were both significant predictors of urine HDA levels in the linear mixed models. Creatinine was a significant covariate when used as an independent variable along with dermal and respirator-adjusted inhalation exposure. Consequently, exposure assessment models must account for the water content of a urine sample. These findings indicate that HDA exhibits a biphasic elimination pattern, with a half-life of 2.9 h for the fast elimination phase. Our results also indicate that urine HDA level is significantly associated with systemic HDI exposure through both the skin and the lungs. We conclude that urinary HDA may be used as a biomarker of exposure to HDI, but biological monitoring should be tailored to reliably capture the intermittent exposure pattern typical in this industry.

Dermal exposure to polycyclic aromatic hydrocarbons in asphalt workers

ObjectivesTo assess dermal exposure to 16 polycyclic aromatic hydrocarbons (PAHs) in asphalt workers by applying polypropylene pads to six body sites (neck, shoulder, upper arm, wrist, groin, ankle), to identify...

Quantitative Plasma Biomarker Analysis in HDI Exposure Assessment

Quantification of amines in biological samples is important for evaluating occupational exposure to diisocyanates. In this study, we describe the quantification of 1,6-hexamethylene diamine (HDA) levels in hydrolyzed plasma of 46 spray painters applying 1,6-hexamethylene diisocyanate (HDI)-containing paint in vehicle repair shops collected during repeated visits to their workplace and their relationship with dermal and inhalation exposure to HDI monomer. HDA was detected in 76% of plasma samples, as heptafluorobutyryl derivatives, and the range of HDA concentrations was < or =0.02-0.92 microg l(-1). After log-transformation of the data, the correlation between plasma HDA levels and HDI inhalation exposure measured on the same workday was low (N = 108, r = 0.22, P = 0.026) compared with the correlation between plasma HDA levels and inhalation exposure occurring approximately 20 to 60 days before blood collection (N = 29, r = 0.57, P = 0.0014). The correlation between plasma HDA levels and HDI dermal exposure measured on the same workday, although statistically significant, was low (N = 108, r = 0.22, P = 0.040) while the correlation between HDA and dermal exposure occurring approximately 20 to 60 days before blood collection was slightly improved (N = 29, r = 0.36, P = 0.053). We evaluated various workplace factors and controls (i.e. location, personal protective equipment use and paint booth type) as modifiers of plasma HDA levels. Workers using a downdraft-ventilated booth had significantly lower plasma HDA levels relative to semi-downdraft and crossdraft booth types (P = 0.0108); this trend was comparable to HDI inhalation and dermal exposure levels stratified by booth type. These findings indicate that HDA concentration in hydrolyzed plasma may be used as a biomarker of cumulative inhalation and dermal exposure to HDI and for investigating the effectiveness of exposure controls in the workplace.

Dermal and Inhalation Exposure to Methylene Bisphenyl Isocyanate (MDI) in Iron Foundry Workers

Diisocyanates are a group of chemically reactive agents, which are used in the production of coatings, adhesives, polyurethane foams, and parts for the automotive industry and as curing agents for cores in the foundry industry. Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) is associated with respiratory sensitization and occupational asthma. However, limited research has been performed on the quantitative evaluation of dermal and inhalation exposure to MDI in occupationally exposed workers. The objective of this research was to quantify dermal and inhalation exposure levels in iron foundry workers. Workers involved in mechanized moulding and mechanized production of cores were monitored: 12 core makers, 2 core-sand preparers, and 5 core installers. Personal breathing-zone levels of MDI were measured using impregnated filter sampling. Dermal exposure to MDI was measured using a tape-strip technique. Three or five consecutive tape-strip samples were collected from five exposed skin areas (right and left forefingers, left and right wrists, and forehead). The average personal air concentration was 0.55 microg m(-3), 50-fold lower than the Swedish occupational exposure limit of 30 microg m(-3). The core makers had an average exposure of 0.77 microg m(-3), which was not significantly different from core installers' and core-sand preparers' average exposure of 0.16 microg m(-3) (P = 0.059). Three core makers had a 10-fold higher inhalation exposure than the other core makers. The core makers' mean dermal exposure at different skin sites varied from 0.13 to 0.34 microg while the two other groups' exposure ranged from 0.006 to 0.062 microg. No significant difference was observed in the MDI levels between the skin sites in a pairwise comparison, except for left forefinger compared to left and right wrist (P < 0.05). In addition, quantifiable but decreasing levels of MDI were observed in the consecutive tape strip per site indicating MDI penetration into the skin. This study indicates that exposure to MDI can be quantified on workers' skin even if air levels are close to unquantifiable. Thus, the potential for uncured MDI to deposit on and penetrate into the skin is demonstrated. Therefore, dermal exposure along with inhalation exposure to MDI should be measured in the occupational settings where MDI is present in order to shed light on their roles in the development of occupational isocyanate asthma.

Fire fighting trainers’ exposure to carcinogenic agents in smoke diving simulators

It is well known that fire fighters are potentially exposed to various carcinogenic agents at a fire scene. An almost unheeded issue, however, is fire fighters’ exposure to carcinogenic agents in smoke diving simulators. Biomonitoring (urinary muconic acid, 1-naphthol and 1-pyrenol), dermal (polycyclic aromatic hydrocarbons) and occupational hygiene measurements (cyanides, hydrogen cyanide, polycyclic aromatic hydrocarbons, volatile organic compounds and formaldehyde) were used to determine how the burning material, the type of simulator and protective clothing used affect fire fighting trainers’ exposure. The highest excretion of 1-pyrenol (sampled 6 h after end of exposure, in average 4.3–9.2 nmol/L) and emissions of benzene (1.0–2.5 mg/m 3) and hydrogen cyanide (0.2–0.9 mg/m 3) were measured during the burning of conifer plywood and chipboard, and the lowest when pure pine and spruce wood (1.5 nmol/L, 0.6 mg/m 3, and 0.05 mg/m 3) was burned. However the safest burning material seemed to be propane (1.0 nmol/L, 0.2 mg/m 3, and not measured). The type of simulator used affected trainers’ exposure very clearly. The highest dermal whole body exposures to polycyclic aromatic hydrocarbons were measured in the fire house simulator (in average 1200 ng/cm 2). Clearly lower exposure levels were measured in container training sessions (760 ng/cm 2), where the average dermal exposure level was 35% lower than in the fire house. The exposure levels (30 ng/cm 2) in the gas simulator in turn, were only 4% of the levels in container training sessions. The amount of polycyclic aromatic hydrocarbons decreased by 80% on trainers’ hands when they used under gloves (in average 8.7 ng/cm 2) compared to those (48.4 ng/cm 2) who did not. There was not difference in protection efficiency against polycyclic aromatic hydrocarbons between tested fire suits (Brage and Bristol).

Dermal Exposure of Pesticide Applicators as a Measure of Coverall Performance Under Field Conditions

In this study, the field performance of two coverall designs used by pesticide applicators was determined. Two coverall types were selected based on data from previously conducted comfort testing under field conditions in southern Europe. Dermal exposure was measured during 22 applications conducted with 11 operators using similar hand-held spray guns in greenhouse pepper crops in the Ierapetra region of Crete, Greece. One of the coverall designs studied was made from a cotton/polyester material treated with a water-repellent Resist Spills(R) finish, which was compared in the field study to a coverall of similar design, but using a woven, untreated cotton material. An in-house analytical method was developed and validated for determining residues of the active substance (a.s.) malathion on the dosimeters. The derived levels of dermal exposure were used as a measure of the protection provided by the two types of coveralls. In addition, by comparing the total amount of the a.s. recovered from outer and inner dosimeters (potential dermal exposure = 238.8 mg kg(-1) a.s. for the cotton coverall and 160.44 mg kg(-1) a.s. for the Resist Spills coverall), a value could be determined for the degree of coverall penetration. The mean penetration (milligrams per kilogram a.s.) of the outer coveralls, calculated as a percentage of the total contamination, was 0.4% for the water-repellent coverall and 2.3% for the cotton coverall. The mean recovery from the laboratory and field-fortified samples was >91 and 74%, respectively and used as the main criterion for quality control of the analytical data. Under the field trial conditions evaluated, both the coverall designs gave better protection than the default values used in the most relevant predictive exposure model. Therefore, they could be considered as appropriate tools of personal protection when both comfort and field performance is taken into account under the specific application scenario.

Assessing inhalatory and dermal exposures and their resultant health-risks for workers exposed to polycyclic aromatic hydrocarbons (PAHs) contained in oil mists in a fastener manufacturing industry

This study first assessed workers' inhalatory and dermal exposures to polycyclic aromatic hydrocarbons (PAHs) contained in oil mists. Then, their resultant lung cancer and skin cancer risks were estimated. Finally, control strategies were initiated from the health-risk management aspect. All threading workers in a fastener manufacturing plant were included. 16 inhalatory and 88 dermal PAH exposure samples were collected. Results show that the inhalatory gas phase total PAH exposure level (8.60 × 10 4 ng/m 3) was much higher than that of particle phase (2.30 × 10 3 ng/m 3). Workers' mean inhalatory exposure level (8.83 × 10 4 ng/m 3) was lower, but its corresponding 1-sided upper 95% confidence level (UCL 1,95% =1.02 × 10 5 ng/m 3) was higher than the time-weighted average permissible exposure level (PEL-TWA) regulated in Taiwan for PAHs (1.00 × 10 5 ng/m 3). The mean whole body total PAHs dermal exposure levels was 5.44 × 10 6 ng/day and the top five exposed surface areas were lower arm, hand, upper arm, neck, and head/front. The estimated lifetime skin cancer risk (9.72 × 10 − 3 ) was lower than that of lung cancer risk (1.64 × 10 − 2 ), but both were higher than the significant risk level (10 − 3 ) defined by the US Supreme Court in 1980. The installation of a local exhaust ventilation system at the threading machine should be considered as the first priority measurement because both lung and skin cancer risks can be reduced simultaneously. If the personal protection equipment would be adopted in the future, both respiratory protection equipment and protective clothing should be used simultaneously.

Development and application of quantitative methods for monitoring dermal and inhalation exposure to propiconazole

Quantitative methods to measure dermal and inhalation exposure to the fungicide propiconazole were developed in the laboratory and applied in the occupational exposure setting for monitoring five farm workers' exposure during pesticide preparation and application to peach crops. Dermal exposure was measured with tape-strips applied to the skin, and the amount of propiconazole was normalized to keratin content in the tape-strip. Inhalation exposure was measured with an OVS tube placed in the worker's breathing-zone during pesticide handling. Samples were analyzed by GC-MS in EI+ mode (limit of detection 6 pg microl(-1)). Dermal exposure ranged from non-detectable to 32.1 +/- 22.6 ng per microg keratin while breathing-zone concentrations varied from 0.2 to 2.2 microg m(-3). A positive correlation was observed between breathing-zone concentrations and ambient air temperature (r2 = 0.87, p < 0.01). Breathing-zone concentrations did not correlate with dermal exposure levels (r2 = 0.11, p = 0.52). Propiconazole levels were below limit of detection when rubber gloves, coveralls, and full-face mask were used. The total-body propiconazole dose, determined for each worker by summing the estimated dermal dose and inhalation dose, ranged from 0.01 to 12 microg per kg body weight per day. Our results show that tape-stripping of the skin and the OVS can be effectively utilized to measure dermal and inhalation exposure to propiconazole, respectively, and that the dermal route of exposure contributed substantially more to the total dose than the inhalation route.