Diet-to-Small Mammal Concentration
When Soil-to-Small Mammal relationships are unavailable, chemical concentrations in vertebrate prey of carnivorous wildlife may be estimated from Diet-to-Small Mammal BAFs. Unlike soil-to-tissue BAFs where the BAF is multiplied by the soil concentration to arrive at the tissue concentration, diet-to-tissue BAFs are multiplied by the chemical concentration in the prey animal’s diet to determine the tissue concentration. Thus, it’s necessary to estimate the chemical concentration in the prey animal’s diet. SADA does this using dietary information specified for Mammalian Prey Diet at the Set Terrestrial Exposure Parameters screen.
Default Diet-to-Small Mammal point estimates appear as Custom BAFs. Defaults are largely based on studies of uptake into beef. When necessary, they were converted from transfer factors in d/kg to BAFs in mg/kg tissue per mg/kg dry food by multiplying the transfer factor by the dry food ingestion rate for beef cows. Users can modify these values if they have site-specific values or prefer values from a source other than that used to derive default values for SADA.
No Diet-to-Tissue regression relationships have been included in SADA, but users who have developed their own relationships may enter the slope and intercept values under Diet-to-Small Mammal Concentration, Tissue Regression if the Diet-to-vertebrate tissue regression relationship is of the form:
where Ctissue = Chemical concentration in vertebrate tissue (mg/kg, dry weight)
Cdiet = Chemical concentration in diet (mg/kg, dry weight)
Slope = coefficient for slope of the regression model
Intercept = value for the y-intercept of the regression model.