PAC Exposure among Asphalt Workers

PI: Robert Herrick, ScD, Harvard School of Public Health
Co-Investigators: Michael McClean, ScD, BUSPH; Jennifer Cavallari, ScD, Harvard School of Public Health

ebrg_6This study investigates the relative contribution of inhalation and dermal exposure to the levels of Polycyclic Aromatic Compounds (PAC) and PAC metabolites in the urine of hot-mix asphalt paving workers. The need for such research was emphasized at the June 2006 International Health Symposium in Dresden Germany, where the true extent of dermal absorption and the relevant biomarkers of exposure were identified as data gaps. To fill this gap, a partnership was formed by researchers from a variety of disciplines, resulting in a study designed to determine the source, nature, pathway, and biological relevance of PAC exposure in hot-mix asphalt paving workers.

Because asphalt emissions occur during paving operations, the workers associated with this process can be exposed to PACs in a variety of ways; this study focuses on inhalation and dermal exposures, where the exposure route could be through the lungs, skin or consumption from sources found in food. We use a repeated measures panel study design to monitor each participant for three days over four different scenarios. Exposures are measured: 1) at baseline under routine paving conditions, 2) without the use of diesel oil (using a PAC-free biofuel substitute), 3) with the addition of respirators to control inhalation exposure, and 4) with the addition of protective clothing to control dermal exposure. Additionally, a control group of non-asphalt exposed construction workers (members of a concrete crew) is included for comparison to the asphalt exposed workers. Since smoking-related PACs are a confounder, smoking is accounted for in the analyses by measuring cotinine levels in each urine sample. Urine cotinine measurements capture both direct and second hand cigarette smoke exposures.

We are investigating the sources of PACs present in the work environment, and the biological relevance (absorbed dose) of these PACs by studying the metabolites present in workers’ urine. Both inhalation and dermal exposure to PACs are determined through detailed chemical, biological and physical analyses (gas, aerosol, particulate). By investigating the chemical make-up of inhalation and dermal exposure analytes and their resulting urinary metabolites, we will assess whether their source can be ascertained.

Publications

  • Cavallari JM, Osborn LV, Snawder JE, Kriech AJ, Olsen LD, Herrick RF, McClean MD. 2012. Predictors of airborne exposures to polycyclic aromatic compounds and total organic matter among hot-mix asphalt paving workers and influence of work conditions and practices. Ann Occup Hyg. 56(2): 138-47.
  • Cavallari JM, Osborn LV, Snawder JE, Olsen LD, Kriech AJ, Herrick RF, McClean MD. 2011. Predictors of dermal exposures to polycyclic aromatic compounds among hot-mix asphalt paving workers. Ann Occup Hyg. Published on-line December 8, 2011.
  • Cavallari JM, Zwack LM, Lange CR, Herrick RF, McClean MD. 2012. Temperature-dependent emission concentrations of polycyclic aromatic hydrocarbons in paving and built-up roofing asphalts. Ann Occup Hyg. Published on-line January 20, 2012.
  • Cavallari JM, Osborn LV, Snawder JE, Kriech AJ, Olsen LD, Herrick RF, McClean MD. 2011. Predictors of dermal exposures to polycyclic aromatic compounds among asphalt paving workers. 5th International Conference on Occupational & Environmental Exposure of Skin to Chemicals. June 5-8. Toronto, Canada.
  • Kriech AJ, Osborn LV, Snawder JE, Olsen LD, Herrick RF, Cavallari J, McClean MD, Blackburn GR. 2011. Study design and methods to investigate inhalation and dermal exposure to polycyclic aromatic compounds and urinary metabolites from asphalt paving workers: Research conducted through partnership. Polycyclic Aromatic Compounds. 31(4): 243-269.
  • McClean MD, Kelsey KT, Sison JD, Quesenberry CP, Wrensch MR, Wiencke JK. 2011. A case-control study of asphalt and tar exposure and lung cancer in minorities. Am J Ind Med. 54: 811-18. PMCID: PMC3196745
  • Osborn LV, Snawder JE, Olsen LD, Kriech AJ, Cavallari J, Herrick RF, McClean MD, Blackburn GR. 2011. Pilot study for the investigation of personal breathing zone and dermal exposure using levels of polycyclic aromatic compounds (PAC) and PAC metabolites in the urine of hot-mix asphalt paving workers. Polycyclic Aromatic Compounds. 31(4): 173-200.
  • Sobus JR, Pleil JD, McClean MD, Herrick RH, Rappaport SM. 2010. Biomarker variance component estimation for exposure surrogate selection and toxicokinetic inference. Toxicol Lett. 199: 247-253. PMCID: PMC2998189.

Presentations

  • Blackburn GR, Osborn LV, Snawder JE, Herrick RF, Olsen LD, McClean MD, Cavallari JM, Kriech AJ. 2009. Monitoring PACs and their metabolites in the urine of hot-mix asphalt paving workers using the Ames mutagenicity assay of their nitrated derivatives. International Symposium on Polycyclic Aromatic Compounds. September 20-24. Charleston, SC.
  • Kriech AJ, Snawder JE, Herrick RF, Olsen LD, McClean MD, Cavallari JM, Osborn LV, Blackburn GR. 2009. Partnerships, processes and study design to investigate the contribution of inhalation and dermal exposure to PACs and related metabolites in the urine of hot-mix asphalt workers. International Symposium on Polycyclic Aromatic Compounds. September 20-24. Charleston, SC.
  • Olsen LD, Snawder JE, Osborn LV, McClean MD, Herrick RF, Cavallari JM, Kriech AJ. 2009. Dermal monitoring of asphalt paving workers: Preliminary baseline results. International Symposium on Polycyclic Aromatic Compounds. September 20-24. Charleston, SC.
  • Osborn LV, Olsen LD, Snawder JE, Kriech AJ, Herrick RF, McClean MD, Cavallari JM. 2009. Inhalation exposure monitoring of asphalt paving workers: Preliminary baseline results with emphasis on polycyclic aromatic compound content. International Symposium on Polycyclic Aromatic Compounds. September 20-24. Charleston, SC.
  • Osborn LV, Snawder JE, Cavallari JM, Olsen LD, Kriech AJ, Blackburn GR, Herrick RF, McClean MD. 2009. Pilot study for the investigation of inhalation and dermal exposure using levels of PACs and PAC metabolites in the urine of hot-mix asphalt paving workers. International Symposium on Polycyclic Aromatic Compounds. September 20-24. Charleston, SC.
  • Snawder JE, Olsen LD, Osborn LV, Herrick RF, McClean MD, Cavallari JM, Kriech AJ. 2009. Polycyclic aromatic compound metabolites in urine of asphalt paving workers; Preliminary results of baseline conditions only. International Symposium on Polycyclic Aromatic Compounds. September 20-24. Charleston, SC.
  • McClean MD, Rinehart RD, Herrick RF. 2006. Dermal Exposure and Urinary 1-Hydroxypyrene among Asphalt Roofing Workers. International Conference on Environmental Epidemiology and Exposure. September 3-6. Paris, France.
  • McClean MD, Rinehart RD, Herrick RF. 2006. Dermal Exposure and Urinary 1-Hydroxypyrene among Asphalt Roofing Workers. Health Effects of Occupational Exposure to Emissions from Asphalt/Bitumen Symposium. June 7-8. Dresden, Germany.
  • McClean MD, Wiencke JK, Kelsey KT, Varkonyi A, Ngo L, Eisen EA, Herrick RF. 2004. DNA Adducts and Polycyclic Aromatic Hydrocarbon Exposure among Asphalt Paving Workers. X2004 Exposure Assessment in a Changing Environment. June 16-18. Utrecht, The Netherlands.
  • McClean MD, Rinehart RD, Ngo L, Eisen EA, Kelsey KT, Wiencke JK, Herrick RF. 2004. Urinary 1-Hydroxypyrene and Polycyclic Aromatic Hydrocarbon Exposure among Asphalt Paving Workers. X2004 Exposure Assessment in a Changing Environment. June 16-18. Utrecht, The Netherlands.
  • McClean MD, Rinehart RD, Ngo L, Eisen EA, Kelsey KT, Herrick RF. 2004. Inhalation and dermal PAH exposure among asphalt workers. Ann Occup Hyg. 48(8): 663-71.
  • McClean MD, Rinehart RD, Ngo L, Eisen EA, Kelsey KT, Wiencke JK, Herrick RF. 2004. Urinary 1-hydroxypyrene and polycyclic aromatic hydrocarbon exposure among asphalt paving workers. Ann Occup Hyg. 48(6): 565-78.
  • Herrick RH, McClean MD, Meeker JD, Zwack L, Hanley K. 2007. Physical and chemical characterization of asphalt (bitumen) paving exposures. J Occup Environ Health. 4 Suppl 1: 209-16.
  • McClean MD, Wiencke JK, Kelsey KT, Varkonyi A, Ngo L, Eisen EA, Herrick RF. 2007. DNA adducts among asphalt paving workers. Ann Occup Hyg. 51(1): p.27-34.
  • McClean MD, Rinehart RD, Sapkota A, Cavallari JM, Herrick RF. 2007. Dermal exposure and urinary 1-hydroxypyrene exposure among asphalt roofing workers. J Occup Environ Health. 4 Suppl 1: 118-26.
  • Sobus JR, Waidyanatha S, McClean MD, Herrick RF, Smith TJ, Garshick E, Laden F, Hart JE, Zheng Y, Rappaport SM. 2009. Urinary naphthalene and phenanthrene as biomarkers of occupational exposure to polycyclic aromatic hydrocarbons. Occup Environ Med. 66(2): 99-104. PMCID: PMC2633650.
  • Sobus JR, McClean MD, Herrick RF, Waidyanatha S, Onyemauwa F, Kupper LL, Rappaport SM. 2009. Investigation of PAH biomarkers in the urine of workers exposed to hot asphalt. Ann Occup Hyg. 53(6): 551-60. PMCID: PMC2723215.
  • Sobus JR, McClean MD, Herrick RF, Waidyanatha S, Nylander-French L, Kupper LL, Rappaport SM. 2009. Comparing urinary biomarkers of inhalation and dermal exposure to polycyclic aromatic compounds in asphalt-exposed workers. Ann Occup Hyg. 53(6): 561-71. PMCID: PMC2723216.
  • Kriech AJ, Snawder JE, Herrick RF, Olsen LD, McClean MD, Cavallari J, Osborn LV, Blackburn GR. 2010. Partnerships, processes, study design and methods to investigate the contribution of inhalation and dermal exposure to polycyclic aromatic hydrocarbons and related metabolites in the urine of hot-mix asphalt workers. In Review.