Estimating dermal contact soil exposure for amphibians

Area of Science:

• Environmental toxicology
• Ecological risk assessment
• Dermal exposure pathways

Background:

• Dermal exposure is an underemphasized route in ecological risk assessment for terrestrial animals.
• Limited data exists for amphibians, hindering accurate exposure modeling.
• Recent studies provide pesticide dose measurements for terrestrial amphibians.

Purpose of the Study:

• To collate and summarize available dermal pesticide exposure data for terrestrial amphibians.
• To compare the performance of two screening exposure models against measured data.
• To provide a database for future model development and bioconcentration factor calculations.

Main Methods:

• Compiled pesticide tissue concentrations from 11 studies involving 11 amphibian species and 14 pesticides.
• Compared measured concentrations to predictions from two models: one bird-surrogate and one amphibian-specific.
• Defined and calculated the false-negative rate (underestimation) for each model.

Main Results:

• The bird-surrogate model did not underestimate amphibian body burdens.
• The amphibian-specific model underestimated measured concentrations in 11.3% of 1158 comparisons.
• A comprehensive database of measured pesticide concentrations was created.

Conclusions:

• Amphibian-specific models are more accurate for estimating dermal pesticide exposure than bird-surrogate models.
• The developed database is valuable for refining ecological risk assessment models for amphibians.
• Addressing dermal exposure is critical for comprehensive ecological risk assessment.