The Barton Springs Salamander (Eurycea sosorum) is an entirely aquatic species of the Family Plethodontidae. It is federally endangered and confined to an area commonly known as Barton Springs in Austin Texas, found within the Edwards Aquifer. Development in the Barton Springs watershed threatens the continued existence of E. sosorum. The principal factor thought to be contributing to its decline is polycyclic aromatic hydrocarbons (PAHs). Asphalt parking lots paved with coal-tar and asphalt sealants have been identified as the probably source of PAHs. The objectives of my project are to: 1) determine if sediments contaminated with coal tar sealants negatively affect eastern newts and San Marcos salamanders through mortality, growth, genotoxicity, or oxidative stress, 2) Calculate uptake of selected PAHs by exposing both species to sediments contaminated with coal tar sealants, 3) Determine if toxicity of coal-tar sealants is altered when exposed to ultraviolet radiation, and 4) determine lethal and sublethal concentration/response relationships between coal tar and asphalt-based sealants to provide information for prospective risk assessment and to assess if asphalt-based sealants are less toxic than coal-tar sealants.
The eastern newt (Notophthalmus viridescens) will be exposed to a range of PAH concentrations with and without UV (290-400nm) and visible light (400-700nm) to determine the concentration/response relationship. Unaltered parent compounds of PAHs can have toxic effects, but oxidation and UV radiation can create structures 100 times more toxic than parent compounds. Spotted salamanders (Ambystoma maculatum) will then be exposed to concentrations similar to those found within Barton Springs with and without UV and visible light. End points during the study will include mortality, growth rates, genotoxicity, liver degeneration, cellular stress, and bioaccumulation.
