Water-quality and ecological assessment of Rottenwood and Sope Creeks, Marietta, Georgia, 2002

Abstract

Discharge of volatile organic compounds from ground water into Rottenwood Creek near Marietta, Georgia, has been documented. In response to a need for information of the effects of these discharges on the aquatic biota of Rottenwood Creek, the U.S. Geological Survey in cooperation with U.S. Air Force Aeronautical Systems Center conducted an assessment of water qual-ity and ecological health of the stream and compared it with a nearby stream, Sope Creek. Aquatic macroinver-tebrate, habitat, and water-quality data were collected in Rottenwood and Sope Creeks to assess water-quality conditions and ecosystem health. To assess potential bioavailability and toxicity of lipophylic compounds in Rottenwood and Sope Creeks, semipermeable mem-brane devices were deployed and Microtox®* micro-scale toxicity testing was conducted on extracts from each site. The water-quality conditions of the two streams were similar and reflected the urban conditions of both watersheds. Chlorinated solvents were detected in Rottenwood Creek but not in Sope Creek. Aquatic communities in Rottenwood and Sope Creeks were similar in composition. Both creeks contained pollu-tion-tolerant EPT taxa. However, Rottenwood Creek contained more species from the order Trichoptera, whereas Sope Creek contained more species from the order Ephemeroptera. In Sope Creek, 50 percent or more of the community at each reach was comprised of Dipterans, suggesting that Sope Creek has slightly more degraded habitat, water-quality, or flow conditions.