übertool: web applications for ecological risk assessment (beta version)
Cloud-based environmental models used by the USEPA for evaluating pesticide risks to ecosystems under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Endangered Species Act (ESA).
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STIR Overview

The STIR model was developed as a screening model to estimate inhalation risk of chemicals to birds and mammals. Chemical specific physical properties are required for executing the model. Vapor phase and droplet-spray exposure risks are estimated in STIR and then compared to avian inhalation or mammalian inhalation and oral toxicity data. Inhalation exposure routes addressed by the model include directly applied spray, volatilization of residues on plant canopy and volatilization of residues in soil.


The exposure estimates are based on the type of application (i.e., air or ground spray, granules, seed treatments) and the quantity of a specified chemical that is to be applied to a field. The screening tool calculates the theoretical maximum pure product air concentration at standard temperature and pressure based on a chemical's vapor pressure and molecular weight. STIR also calculates inhalation rates and inhalation dose as a function of saturated air concentration, inhalation rate and animal weight. Toxicity endpoints are estimated using adjusted LD50 values. Model results are presented as a ratio of the inhalation exposure dose to toxicity. To determine if inhalation exposure to a particular chemical warrants further investigation, ratios are compared to threshold values.