PAH Concentrations in Lake Sediment Decline Following Ban on Coal-Tar-Based Pavement Sealants in Austin, Texas

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• 作者：Peter C. Van Metre ; Barbara J. Mahler
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：July 1, 2014
• 年：2014
• 卷：48
• 期：13
• 页码：7222-7228
• 全文大小：291K
• ISSN：1520-5851

文摘

Recent 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鈥檚 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 (鈭慞AH₁₆) in dated core intervals and surficial bottom-sediment samples collected from sites in the lower lake declined about 44% from 1998鈥?005 to 2006鈥?014 (means of 7980 and 4500 渭g kg^鈥?, respectively), and by 2012鈥?014, the decline was about 58% (mean of 3320 渭g kg^鈥?). Concentrations of 鈭慞AH₁₆ 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鈥?998) 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.