es405691q_si_003.xlsx (126.03 kB)
PAH Concentrations in Lake Sediment Decline Following Ban on Coal-Tar-Based Pavement Sealants in Austin, Texas
dataset
posted on 2014-07-01, 00:00 authored by Peter C. Van Metre, Barbara J. MahlerRecent
studies have concluded that coal-tar-based pavement sealants
are a major source of polycyclic aromatic hydrocarbons (PAHs) in urban
settings in large parts of the United States. In 2006, Austin, TX,
became the first jurisdiction in the U.S. to ban the use of coal-tar
sealants. We evaluated the effect of Austin’s ban by analyzing
PAHs in sediment cores and bottom-sediment samples collected in 1998,
2000, 2001, 2012, and 2014 from Lady Bird Lake, the principal receiving
water body for Austin urban runoff. The sum concentration of the
16 EPA Priority Pollutant PAHs (∑PAH16) in dated
core intervals and surficial bottom-sediment samples collected from
sites in the lower lake declined about 44% from 1998–2005 to
2006–2014 (means of 7980 and 4500 μg kg–1, respectively), and by 2012–2014, the decline was about 58%
(mean of 3320 μg kg–1). Concentrations of
∑PAH16 in bottom sediment from two of three mid-lake
sites decreased by about 71 and 35% from 2001 to 2014. Concentrations
at a third site increased by about 14% from 2001 to 2014. The decreases
since 2006 reverse a 40-year (1959–1998) upward trend. Despite
declines in PAH concentrations, PAH profiles and source-receptor modeling
results indicate that coal-tar sealants remain the largest PAH source
to the lake, implying that PAH concentrations likely will continue
to decline as stocks of previously applied sealant gradually become
depleted.