PW14 Probabilistic Ecological Risk Assessment
Exhibit Hall
8:00 AM - Wednesday

(PW237) A probabilistic model of rodenticide exposure to non-target predators and scavengers.

Giddings, J1, Warren-Hicks, W2, Mortensen, S3, Edwards, P4, 1 Parametrix, Inc., Rochester, MA, USA2 The Cadmus Group, Inc., Chapel Hill, NC, USA3 Syngenta Crop Protection, Greensboro, NC, USA4 Syngenta Crop Protection, Jealotts Hill, Bracknell, Berks, UK

ABSTRACT- A probabilistic model was developed to estimate the concentrations of rodenticide in the bodies of predators or scavengers whose food may contain rodenticide residues. The basic model estimated dietary ingestion of rodenticide as a function of the animal's food ingestion rate, the fraction of its diet that consists of rodents, the fraction of rodents that have been exposed to rodenticide baiting programs, and the concentration of rodenticide residues in exposed rodents. A simple uptake-depuration model was then used to simulate rodenticide concentrations in the predator or scavenger over a 90-d period. The maximum concentration during the 90-d period was selected as the primary analytical output of the model. Many key input parameters in the model were represented by distributions of values (often based on field data), and the model generated distributions of 90-d maximum concentrations. The output distributions reflected day-to-day variability in the diet of an individual predator, and variability in overall diet among individual predators in a specific habitat. The output of the exposure model was integrated with rodenticide dose-response data to generate probabilistic risk curves, as described in the accompanying poster by Warren-Hicks et al. Through selection of input parameter assumptions, the exposure model can be used to explore different situations of interest (season, location, habitat, rodenticide use, etc.).

Key words: wildlife, rodenticide, probabilistic risk assessment, exposure

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