Diet

A receptor’s diet is described by the proportion of each food type that makes up its total diet. Food types currently allowed in SADA include plants (foliage and/or seeds), invertebrates, and vertebrates. All types of invertebrates are lumped into Fraction Insect, and all types of vertebrates are lumped into Fraction Mamm. The fraction of plants, invertebrates, and vertebrates in the diet should sum to 1.

Mammalian Prey Diet

Mammalian prey diet is only used when Fraction Mammal is >0 and no soil-to-small mammal bioaccumulation factor is available. Modeling the dose to wildlife receptors requires information on the chemical concentration in the foods they eat. This is fairly straight-forward when soil-to-plant tissue, soil-to-invertebrate tissue, or soil-to-small mammal tissue bioaccumulation factors or regressions are available, since these can be used to estimate food type concentrations directly from the chemical concentration in soil. However, for some chemicals, soil-to-small mammal tissue factors are unavailable, and only diet-to-small mammal tissue biotransfer factors are available. In order to estimate the chemical concentration in vertebrate prey of carnivorous wildlife in these cases, it is necessary to specify the diet of the vertebrate prey. The default in SADA is a small omnivorous mammal consuming 50% plants and 50% invertebrates with soil ingestion equal to 3% of its total food ingestion. The concentration in the diet of the vertebrate prey is then multiplied by the diet-to-tissue transfer factor to estimate the chemical concentration in vertebrate prey.