PAHs in House Dust and their Relation to Pavement Sealcoat

1. PAHs in House Dustand their Relation to Pavement Sealcoat Barbara J. Mahler and Peter C. Van Metre U.S. Geological Survey

2. Benzo(a)pyrene Pyrene Naphthalene What are polycyclic aromatic hydrocarbons (PAHs)?

3. Why are PAHs going up???

4. The first clues

5. Coal-tar sealcoat = Used motor oil

7. Sealcoated Pavement Dust PAH (mg/kg) Asphalt Coal tar 5.2 570 <13 3,400 1,300 3,800 2.1 3,200 1,200 Composite dust sample

9. Where is it going?

10. 23 ground-floor apartments “coffee” = asphalt sealcoat “tea” = coal-tar sealcoat

11. Median SPAH [mg/g] n=12 n=11 5.1 129 9.0 4,760 Out-CT = 530 * Out-NCT In-CT = 25 * In-NCT

12. Factors explaining PAH in house dust • Coal-tar based sealcoat explains ~50% of variance in log-transformed T-PAH • Coal-tar based sealcoat and urban land-use together explain 60% of variance

13. SB2PAH [mg/g] max 156 2.6 47 4.4 2,040 > 40 mg/g SB2 PAH results in excess cancer risk of > 1 x 10-4 (Maertens et al., 2004)

14. Benzo[a]pyrene [mg/g] max 24.2 0.44 4.5 0.53 285 Exposure to 10 mg/g should be minimized to avoid adverse health effects (German Federal Environmental Agency)

15. Conclusions and Implications • Coal-tar based pavement sealcoat associated with elevated PAHs in house dust • Concentrations and human health risk