Summary

Description

Aquatic habitat of the endangered Barton Springs salamander, Eurycea sosorum, in Travis County, Texas can potentially be impacted by contaminants in surface runoff from urbanized areas. This study was conducted to 1 determine types and levels of pydrophobic contaminants in springdischarged sediment in four habitat springs of the salamander during major precipitation events and 2 define timecourse differences in contaminant levels for the four habitat springs during these events. Suspended sediment from the four habitat springs was sampled and analyzed for hydrophobic contaminants after rainstorm events had caused turbid flow at these springs. Soluble pesticides were also sampled from each spring during a single rain event in May 2000. Eight trace metals As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were present in varying concentrations in suspended sediment samples taken at the four habitat springs. Arsenic and nickel exceeded TELs threshold effects levels on a relative basis for all recorded rainfall events in the springs. Nickel concentrations exceeded a relative PEL probable effects level at least once in all four springs during a rainfall event. Five soluble pesticides atrazine, simazine, metolachlor, diazinon, and prometon were detected in at least one sample from the four springs. Deethylatrazine a degredate of atrazine was also detected. Although these contaminants occurred within salamander habitat during the years of 2000 to 2002 in concentrations that are below lethal dosages for the salamander and its prey, additional analyses should be made on both an acute and chronic basis to ensure that contaminant exposure does not reach concentrations that can impact the salamander or its habitat. In addition, future toxicity testing involving this highly endangered amphibian should include sublethal endpoints such as effects on growth and reproduction.