PARENT SESSION
Poster Session #12: Modeling.
Tuesday, August 7, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall
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The use of AQUATOX to disaggregate the effects of multiple stressors on aquatic ecosystems.
Park, Richard1, Wellman, Marjorie2, Mauriello, David 2, Clough, Jonathan1, 1 2
ABSTRACT- The combined effects of nutrients, toxic substances, suspended sediments, and key species are very important in water management. Increasingly there is a need to disaggregate effects, identify causal relationships, and determine key stressors that are subject to control. The US EPA recently released and is actively enhancing a simulation model that is capable of examining complex ecological relationships. The AQUATOX model integrates aquatic ecosystem, chemodynamic, bioaccumulative, and ecotoxicologic modules. It can simulate the simultaneous effects of up to 20 toxic chemicals and conventional pollutants on as many as 34 algal, macrophyte, invertebrate, and fish groups plus up to 15 age classes of one game fish; and it can perform Latin hypercube uncertainty analysis. Simulations of Coralville Reservoir, Iowa, represent the combined effects of pesticides, suspended sediments, nutrients, and detrital loadings and have been used to resolve causal relationships. The model successfully forecast the recovery of an important bass fishery as dieldrin levels decreased over a period of years; it also suggested the impacts of detrital and suspended sediment loadings on a commercial buffalofish fishery. Simulations of in-stream experiments in Walker Branch, Tenn., correctly predicted the separate impacts of grazing, light, and nutrients on periphyton and confirmed the theoretical basis for the importance of the lengths of food chains. Application to Hyalite Creek, Mont., verified the importance of both nutrients and scour on periphyton.
KEY WORDS: model, toxic, nutrient, risk