M3 AM Ecological Risk Assessment (Part 1)
Monday, 14 November 2005: 8:00 AM - 11:40 AM in Ballroom 3

(JOH-1117-765772) Use of the SPMD-TOX paradigm for toxicological risk assessment of urban streams in six major metropolitan areas of the United States.

Johnson, B¹, Goodbred, S², Huckins, J¹, ¹ USGS, Columbia Environmental Research Center, Columbia, MO, USA² USGS, Sacramentp, CA, USA

ABSTRACT- Toxicological risk assessments to determine the effects of urban land-use on aquatic communities in six major metropolitan areas in the United States were conducted as part of the National Water Quality Assessment (NAWQA) program effects of urbanization on stream ecosystems (EUSE) study. Managing aquatic resources in rapidly developing urban areas though out the U.S. is becoming a challenge. One hundred and sixty sites in urban streams, from MidAtlantic, Midwestern, Southern, and Western states were monitored over 30-day periods for the bioavailability of hydrophobic organic contaminants. Toxicological risk assessments were made using the SPMD-TOX paradigm: semipermeable membrane devices (SPMD) to collect and concentrate bioavailable aquatic contaminants in situ and short-term microscale toxicity tests (TOX) -- Fluoroscan, Microtox, Mutatox, and three direct small scale invertebrate tests -- to detect waterborne bioavailable ecotoxins. SPMD-TOX assessment clearly indicated that hydrophobic contaminants and potential toxicity increase in streams as urban intensity increases in all six major metropolitan areas. Hot spots or areas of concern for the resource managers were also identified and may be caused by specific point sources of pollution. SPMD-TOX was a sensitive, technically simple, and cost-effective tool to monitor and assess urban streams for chemical contaminants that may adversely affect aquatic communities and water quality.

Key words: SPMD-TOX, NAWQA, Risk Assessment, Microscale Testing