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Causes of Increasing Concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in U.S. Lakes U.S. Department of the Interior U.S. Geological Survey
Causes of Increasing Concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in U.S. Lakes
U.S. Department of the InteriorU.S. Geological Survey
PAHs are increasing in urban lakes
Van Metre et al., Environ. Sci. Technol., 2005
What are polycyclic aromatic hydrocarbons (PAHs)?
Benzo(a)pyrene
PyreneNaphthalene
In 1975, 11% urban
Lake in the Hills, near Chicago
In 2000, 78% urban
Lake in the Hills, IL
0
400
800
1200
1600
1940 1960 1980 2000 2020
Po
pu
lati
on
Den
sity
(/k
m2)
0
2
4
6
8
10
12
14
To
tal
PA
H (
mg
/kg
)
Population and PAH in lake sediment
Population
PAHs
City of Austin measures PAH concentrations greater than 1,500 mg/kg
What could be the source?
• Fresh asphalt 1.5• Weathered asphalt 3• Fresh motor oil 4• Brake particles 16• Road dust 24• Tire-wear particles 86• Diesel engine emissions 102• Gasoline engine emissions 370• Used motor oil 440
1,500 mg/kg in creek sediment
Pavement Sealcoat
Asphalt-based
50
Coal-tar-based
100,000
Coal-tar sealcoatCoal-tar sealcoat
Used motor oilUsed motor oil
=
Mahler et al., Env. Sci. Technol., 2005
5.2<13
2.1
3,000
570
3,2003,400
3,200
1,3000
Sealed Parking Lots (mg/kg)
Unsealed Parking Lots
Asphalt Coal tar 8.5<8.6
0.83
54
24
2147 30
Asphalt Coal tar
Van Metre et al., Environ. Sci. Technol., 2009
What’s causing upward trends in PAHs?
Environmental forensics: PAH “fingerprints”
0
0.05
0.1
0.15
0.2
0.25
CT dust
Lake Anne
12 PAHs
Fra
ctio
n
0
0.05
0.1
0.15
0.2
0.25Gas vehicle
Lake Anne
12 PAHs
Fra
ctio
n
0
0.05
0.1
0.15
0.2
0.25 Coal
Lake Anne
12 PAHs
Fra
ctio
nPAH fingerprints and Lake Anne sediment
r=0.60
r=0.68
r=0.94
burning
Lake Anne, Reston, Virginia
Date sediment deposited
1970 1980 1990 2000
PA
H c
once
ntra
tion
(mg/
kg)
0
5
10
15
20
25
Lake Anne, Reston, Virginia
Date sediment deposited
1970 1980 1990 2000
PA
H c
once
ntra
tion
(mg/
kg)
0
5
10
15
20
25
Lake Anne, Reston, Virginia
Date sediment deposited
1970 1980 1990 2000
PA
H c
once
ntra
tion
(mg/
kg)
0
5
10
15
20
25
Lake Anne, Reston, Virginia
Date sediment deposited
1970 1980 1990 2000
PA
H c
once
ntra
tion
(mg/
kg)
0
5
10
15
20
25
Lake Anne, Reston, Virginia
Date sediment deposited
1970 1980 1990 2000
PA
H c
once
ntra
tion
(mg/
kg)
0
5
10
15
20
25
Total PAH
Wood burning
VehiclesCoal burning
Coal-tar sealcoat
Sources of PAHs to Sediment in Lake Anne Reston, VA
PAH sources to U.S. urban lakes
Coal-tar-based sealcoat
Probable effects concentration
Van Metre and Mahler, Sci. Total Environ., 2010
Without coal-tar-based sealcoat, the urban PAH baseline is low
Probable effects concentration
Five lakes with the lowest PAH
contribution from coal-tar sealcoat
Five lakes with the highest PAH
contribution from coal-tar sealcoat
Biological effects
Bommarito et al., 2010, EcotoxicologyBommarito et al., 2010, ChemosphereBryer et al., 2009, Environ. Poll.Bryer et al., 2006, EcotoxicologyScoggins et al., 2006, J. NABS
Photos from Jupiter Images and Corbis Images, Inc.
23 ground-floor apartments
5.15.1
9.09.0
129129
4,7604,760
Median total PAH [mg/kg]
n=12 n=11
Mahler et al., 2010, Environ. Sci. Technol.
PAHs are increasing in urban lakes nationally
High PAH concentrations? Use is extensive? Particles are mobile?
PAHs in house dust are elevated where coal-tar-based
sealcoat is used
Coal-tar-based sealcoat is the largest contributor of PAHs to
urban lakes
√√√
USGS publications on sealcoat and PAHs in peer-reviewed journals
Van Metre, P. C.; Mahler, B. J., 2010, Contribution of PAHs from Coal-Tar Pavement Sealcoat and Other Sources to 40 U.S. Lakes. Sci. Total Environ., v. 409, 334-344.
Mahler, B. J.; Van Metre, P. C.; Wilson, J. T.; Musgrove, M.; Burbank, T. L.; Ennis, T.; Bashara, T. J., 2010, Coal-tar-based parking lot sealcoat: An unrecognized source of PAH to settled house dust. Environ. Sci. Technol., v. 44, 894-900.
Yang, Y., Van Metre, P.C., Mahler, B.J., Wilson, J.T., Ligouis, B., Razzaque, M.M., Schaeffer, D.J., and Werth, C.J., 2010, Influence of coal-tar sealcoat and other carbonaceous materials on polycyclic aromatic hydrocarbon loading in an urban watershed. Environ. Sci. Technol., v. 44, p. 1217-1223.
Van Metre, P. C.; Mahler, B. J.; Wilson, J., 2009, PAHs underfoot: Contaminated dust from sealcoated pavements. Environ. Sci. Technol., v. 43, 20-25.
Van Metre, P.C., and Mahler, B.J., 2005, Trends in Hydrophobic Organic Contaminants in Lake Sediments Across the United States, 1970-2001. Environ. Sci. Technol., v. 39, p. 5567-5574.
Mahler, B. J.; Van Metre, P. C.; Bashara, T. J.; Wilson, J. T.; Johns, D. A., 2005, Parking lot sealcoat: An unrecognized source of urban PAHs. Environ. Sci. Technol., v. 39, 5560-5566.
http://tx.usgs.gov/coring/allthingssealcoat.html
Barbara Mahler, [email protected](512) 927-3566
Peter Van Metre, [email protected](512) 927-3506
How do some sources compare?Milligrams of PAH in:
• One storm on a CT sealed driveway 56 mg (Mahler et al., 2005)
• One storm on a CT sealed driveway 174 mg (Watts et al., 2011)
• Driving 12,000 miles (tail pipe) 56 mg (Bergvall and Westerholm, 2009)
• Driving 23,000 miles (tire wear) 56 mg (Aatmeeyata, 2010)
• One storm on an unsealed driveway 0.86 mg (Mahler et al., 2005)
