Coal-Tar Based Pavement Sealcoat, Pahs, and Environmental

You’re standing on it! Coal‐tar‐based pavement sealcoat, PAHs, and Environmental Contamination

1 Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the urban environment

Benzo(a)pyrene

2 NAWQA: Contaminant Trends in Lake Sediment http://tx.usgs.gov/coring/index.html

3 Trends since 1970

Van Metre et al., 2000, Environ. Sci. &Tech. Van Metre and Mahler, 2005, Environ. Sci. & Tech. 4 Lake in the Hills, near Chicago

In 1975, 11% urban

In 2000, 78% urban

5 Population and PAH in lake sediment

Lake in the Hills, IL

1600 14 12 1200 10 8 800 6 4

400 (mg/kg) PAH Total 2

Population Density (/km2) Population Density 0 0 1940 1960 1980 2000 2020

6 The first clue: high PAH in Austin stream sediment

 Extremely high (>1,500 mg/kg) PAHs in some small drainages

 Compare to Probable Effect Concentration (PEC) of 23 mg/kg

 So … what’s upstream? 8 PAHs in urban sources All concentrations in mg/kg (averages of up to 6 studies)

• Fresh asphalt 1.5 Pavement Sealcoat • Weathered asphalt 3 • Fresh motor oil 4 •Asphalt Based • Brake particles 16 ~ 50 • Road dust 24 • Tire particles 86 •Coal‐tar‐based • Diesel engine 102 • Gasoline engine 370 ~70,000 • Used motor oil 440

9 Is use of sealcoat extensive?

• 85 million gallons per – 4 watersheds in Texas: year (per industry) 1‐2% area • 170 mi 2, or 110,000 ac – 1 watershed in Illinois: covered 4% of area • 42% of parking lot area • 89% of driveway area Are contaminants in sealcoat mobile?

11 Sealcoat PAH transport pathways

12 Sealed pavement dust Total PAH (mg/kg) 5.2 <13 570 1,300 3,400 3,200 2.1 3,200 Unsealed pavement dust 3,000 8.5 <8.6 24 30 Asphalt Coal tar 47 21 0.83

Asphalt Coal tar Van Metre et al., 2009, Environ. Sci. & Tech. 13 Sealcoat PAH transport pathways

14 PAH in runoff Sampled runoff from 13 parking lots Analyzed particles and water for PAHs

15 PAH in particles from parking lots

3,500 Black R. Ohio, EPA Superfund Site 1,100 mg/kg Mean concentration is Charles65-times River greater 130 mg/kg

Total PAH (mg/kg) PAH Total 54 PEC Mean Urban Lakes 12 mg/kg

Mahler et al., 2005, Env. Sci. & Tech. 16 Sealcoat PAH transport pathways

17 Environmental Forensics: PAH fingerprints

0.25 Coal

Lake Anne 0.2 r=0.60 0.15

0.1 0.25 Fraction CT dust 0.05 0.2 Lake Anne 0 12 PAHs 0.15 r=0.94 Phe Anth Flu Pyr BaA Chry BbF BkF BeP BaP IP BgP

0.25 Fraction 0.1 Gas vehicle

3 ring 4 ring 5-6 ringLake Anne 0.2 0.05 r=0.68 0.15 0 12 PAHs 0.1 Phe Anth Flu Pyr BaA Chry BbF BkF BeP BaP IP BgP Fraction

0.05

0 12 PAHs 18 Phe Anth Flu Pyr BaA Chry BbF BkF BeP BaP IP BgP CMB* source apportionment

 Vehicle/traffic related Gasoline and diesel soot and exhaust, tunnel air, used oil, tires, asphalt wear  Coal combustion Residential, power plant, and coking plant emissions  Fuel oil combustion  Wood burning Pine-wood soot particles  Coal-tar-based sealcoat NIST standard, products, scrapings, and pavement dust

*EPA contaminant mass balance model

19 PAH sources to U.S. urban lakes

Probable Effect Concentration

Van Metre and Mahler, 2010, STOTEN 20 PAH Trends in New Urban Lakes A large coal‐tar‐sealcoat contribution translates to high PAH concentrations

Probable effect concentration

22 Stormwater ponds unsealed in South Carolina

PAH=1 mg/kg

PAH=45 mg/kg sealed

Weinstein et al., Environ. Monit. & Assess., 2010 23 Effects on aquatic biota

Bommarito et al., 2010, Ecotoxicology Bommarito et al., 2010, Chemosphere Bryer et al., 2009, Environ. Poll. Bryer et al., 2006, Ecotoxicology Scoggins et al., 2006, J. NABS

24 Sealcoat PAH transport pathways

25 Coal‐tar‐based pavement sealcoat

√ High PAH concentrations? √ Use is extensive? √ Documented off‐site transport?

Contaminates dust, soils, Demonstrated adverse runoff, stormwater ponds, effects on aquatic life and lakes, homes, and air: PAHs potential concerns for are 10s to 1,000s of times human health background

Barbara Mahler: [email protected] http://tx.usgs.gov/coring/allthingssealcoat.html 26