AQUAWEB (Aquatic Food Web) model

AQUAWEB is a site-specific bioaccumulation model for aquatic food webs and provides estimates of chemical concentrations in organisms of aquatic food webs from chemical concentrations in the water and the sediment. The model is presented in rate constant format for assessing the bioaccumulation of non-ionic hydrophobic organic chemicals at steady-state.

For zooplankton, aquatic invertebrates and fish the model calculates rates of chemical uptake from the water and the diet and rates of chemical elimination to the water, feces and the “pseudo-loss” mechanism of growth dilution. Metabolic biotransformation rate data can also be included as a mechanism of chemical elimination (see database and the BCFBAF module of US EPA EPI Suite™). AQUAWEB is a modification of a previous food web model (Gobas 1993). The models are intended to estimate chemical concentrations and associated bioconcentration factors (BCF), bioaccumulation factors (BAF) and biota-sediment accumulation factors (BSAF) of non-ionic hydrophobic organic chemicals. The models are useful for assessing exposure and risks of chemicals in the water and sediment to organisms in aquatic ecosystems and higher trophic level organisms that eat aquatic species such as birds and mammals, including humans.

Both the Gobas 1993 and Arnot and Gobas 2004 models have been evaluated using empirical data from three different freshwater ecosystems involving 1,019 observations for 35 species and 64 chemicals and are coded in one Microsoft Excel™ workbook. The AQUAWEB model also forms the basis of the U.S. Environmental Protection Agency’s KABAM model used primarily for pesticide assessments.

Full details of the 2004 model are available in the following publication:

– Arnot JA, Gobas FAPC. 2004. A food web bioaccumulation model for organic chemicals in aquatic ecosystems. Environ Toxicol Chem 23(10): 2343–2355.

Versions for Download: For earlier versions of the AQUAWEB model please contact Jon Arnot.

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