Dermal Exposure and Urinary 1-Hydroxypyrene among Asphalt Roofing Workers

Abstract

The primary objective of this study was to identify significant determinants of dermal exposure to polycyclic aromatic compounds (PACs) among asphalt roofing workers and use urinary 1-hydroxyprene (1-OHP) measurements to evaluate the effect of dermal exposure on total absorbed dose. The study population included 26 asphalt roofing workers who performed three primary tasks: tearing off old roofs (tear-off), putting down new roofs (put-down), and operating the kettle at ground level (kettle). During multiple consecutive work shifts (90 workerdays), dermal patch samples were collected from the underside of each worker's wrists and were analyzed for PACs, pyrene, and benzo(a)pyrene (BAP). During the same work week, urine samples were collected at pre-shift, post-shift, and bedtime each day and were analyzed for 1-OHP (205 urine samples). Linear mixed effects models were used to evaluate the dermal measurements for the purpose of identifying important determinants of exposure, and to evaluate urinary 1-OHP measurements for the purpose of identifying important determinants of total absorbed dose. Dermal exposures to PAC, pyrene, and BAP were found to vary significantly by roofing task (tear-off > put-down > kettle) and by the presence of an old coal tar pitch roof (pitch > no pitch). For each of the three analytes, the adjusted mean dermal exposures associated with tear-off (812 ng PAC/cm2, 14.9 ng pyrene/cm2, 4.5 ng BAP/cm2) were approximately four times higher than exposures associated with operating the kettle (181 ng PAC/cm2, 4.1 ng pyrene/cm2, 1.1 ng BAP/cm2). Exposure to coal tar pitch was associated with a 6-fold increase in PAC exposure (p = 0.0005), an 8-fold increase in pyrene exposure (p < 0.0001), and a 35-fold increase in BAP exposure (p < 0.0001). Similarly, urinary 1-OHP levels were found to be significantly higher on days when an old pitch roof was removed, accounting for a 3.7-fold difference at pre-shift (p = 0.01), a 5.0-fold difference at post-shift (p = 0.004), and a 7.2-fold difference at bedtime (p = 0.002). The pyrene measurements obtained during the work shift were found to be strongly correlated with urinary 1-OHP measurements obtained at the end of that shift (r = 0.8, p < 0.001) as well as at bedtime (r = 0.7, p < 0.001). Ultimately, the results of a distributed lag model indicated that dermal exposure during the preceding 40 hours had a statistically significant effect on urinary 1-OHP. The presence of coal tar pitch was the primary determinant of dermal exposure, particularly for exposure to BAP. However, the task-based differences that were observed while controlling for pitch suggest that exposure to asphalt also contributes to dermal exposures. We found that dermal exposure was a significant determinant of total absorbed dose, suggesting that control strategies aimed at reducing occupational exposure to PACs should include an effort to minimize dermal exposure.

Analysis of Polycyclic Aromatic Hydrocarbons in Amniotic Fluid Samples From Smokers and Nonsmokers

“…Previous studies have focused only on the detection of 1-hydroxypyrene as a biomarker of exposure relating to polycyclic hydrocarbons, especially in urinary samples obtained from smokers and nonsmokers (174)(175)(176)(177)(178)(179)(180)(181). Although the presence of this compound generally indicates the presence of other compounds of the same classification, it fails to be a marker of specific polycyclic aromatic hydrocarbons, especially those compounds that may result in a more significant toxicological effect on the fetus.…”

Review and implications of IARC monograph 103 outcomes for the asphalt pavement industry

“…wearing gloves and/or long sleeves) (Cavallari et al, 2012b) to reduce dermal exposures. McClean et al (2007) provided evidence that PACs in air are dermally absorbed and confirmed that reducing the application temperature of bitumen mix, increasing dermal coverage of workers and substituting biodiesel for diesel oil as a cleaning agent appear to be promising strategies for reducing PAC exposure among paving workers. Showering after work also minimises risk of dermal absorption (McClean et al, 2007).…”

“…McClean et al (2007) provided evidence that PACs in air are dermally absorbed and confirmed that reducing the application temperature of bitumen mix, increasing dermal coverage of workers and substituting biodiesel for diesel oil as a cleaning agent appear to be promising strategies for reducing PAC exposure among paving workers. Showering after work also minimises risk of dermal absorption (McClean et al, 2007). Smith et al (2011) reported a method for determining urinary PAC metabolites using an ELISA immunoassay method that shows promise as a more rapid and less costly routine method for determining worker exposure to PACs in bitumen emissions as compared to liquid-liquid extraction with gas chromatography/isotope dilution high-resolution mass spectrometry.…”

“…In addition to identifying temperature as a predictor of PAC exposure, Cavallari et al (2012aCavallari et al ( , 2012b and McClean, Rinehart, Sapkota, Cavallari, and Herrick (2007) reported that reduction of airborne exposures to PACs among HMA paving workers can be achieved by substituting biodiesel for diesel oil as a cleaning agent (Cavallari et al, 2012a). Substituting biodiesel for diesel oil as a cleaning agent, and decreasing the HMA application temperature of dermal exposure also reduced dermal exposures to PACs; but the authors also recommended the use of dermal coverage (e.g.…”

Meta-Analysis of Lung Cancer in Asphalt Roofing and Paving Workers with External Adjustment for Confounding by Coal Tar

“…NIOSH industrial hygiene surveys have concluded that workers exposed to coal tar tear-off dust are exposed to higher airborne concentrations of organic particulate and PAHs than workers involved with the application of hot coal tar pitch. (30,31) The significance of coal tar dust as a source of PAH exposure was reinforced by McClean's (32) recent findings that exposure to coal tar pitch dust during tear-offs of old roofs was associated with roughly (1) Coke oven workers 7-18; 8-135; 63 (GM A ) Coal gas production Armstrong et al (18) Retorts 3 By-products 0.5 IARC Monographs vol. 34 (19) Retort (19) Vertical-stud: Soderberg 0.7-9.0; 13-116 (GM 38); 7-184 (GM 36)…”