Wednesday, June 6, 2007 - 11:45 AM
210

Occurrence and effects of PAHs on stream benthic macroinvertebrate communities below coal tar sealed parking lots

Mateo Scoggins1, Pamela J. Bryer2, Nancy L. McClintock1, and Leila Gosselink1. (1) Watershed Protection and Development Review, City of Austin, 505 Barton Springs Road, 11th Floor, Austin, TX 78704, (2) The Institute of Environmental and Human Health, Texas Tech University, 1207 Gilbert Drive, Reese Center, Lubbock, TX 79416

Parking lot pavement sealants have recently been recognized as a major source of Polycyclic Aromatic Hydrocarbons (PAHs) in urban stream sediments in Austin, Texas.  Laboratory and field studies have shown that PAHs in sediments can be toxic to aquatic organisms and can degrade aquatic communities.  After identifying increases in concentrations of PAHs in sediments below seal-coated parking lots, we investigated whether the increases had significant effects on stream biota in 5 Austin streams.  We sampled sediment chemistry and biological communities both above and below the point at which stormwater runoff from the parking lots discharge into the streams, thus providing 5 upstream reference sites and 5 downstream treatment sites.  Differences between upstream and downstream concentrations of total PAH ranged from 3.9 to 32 mg/kg. Analysis of the species occurrence data from pool and riffle habitats indicate a significant decrease in community health at the downstream sites, including decreases in richness, intolerant taxa, dipteran taxa, and density.