PARENT SESSION
MP2 - Aquatic Toxicology
Chair: Spehar, Bob1, 1 U.S. EPA, Duluth, MN
Co-chair: Henry, Mary2, 2 U.S. Fish and Wildlife Service, Arlington, VA
2:10 PM to 5:30 PM - Monday, 18 November 2002
Room Ballroom J
(266) Lessons learned during 15 years of surfactant research in the P&G Experimental Stream Facility.
Belanger, Scott*,1, 1 Procter & Gamble, Cincinnati, OH, USA
ABSTRACT- Procter & Gamble operated a full-scale experimental stream mesocosm facility to test ecological and toxicological hazard assessment predictions based on lower tiers of data for approximately 15 years. A standardized approach was used to evaluate anionic, cationic, and nonionic surfactants. Studies typically utilized an 8-week biological colonization period followed by 8 weeks of exposure. Streams were operated on a continuous, once-through basis. Detailed assessments of microbial, protozoan, and invertebrate community structure and function, environmental fate and exposure, and in situ single species toxicity tests were included. Testing of 8 high volume surfactants (many among those used at the highest industry volumes) provided detailed fate and effect profiles that universally affirmed the conservative nature of laboratory single species approaches. In addition to this direct result addressing the primary objective of the initial ESF program, the standardized nature of the long-term research program allowed many higher-order conclusions regarding experimental stream testing and ecological extrapolation. Some representative examples include: 1. development of a structure-activity-relationship for a range of alcohol ethoxylate non-ionic surfactants allowing quantitative interpolation of AE mixtures; 2. evidence in support of the subsidy-stress gradient hypothesis (Odum 1979) for rapidly biodegrading surfactants; 3. determination of quantitative mesocosm to field extrapolation relationships over a regional to national scale; 4. assessments of the influence of temperature on biodegradation; and, 5. demonstrations of the repeatability of studies on the same compound. These findings and specific conclusions from individual surfactant tests will be reviewed.
Key words: mesocosm, field, surfactant, experimental stream