Benchmark Dose Analysis from Multiple Data Sets: The Cumulative Risk Assessment for N-Methyl Carbamate Pesticides

• Activity Number: 78
• Type: Contributed
• Date/Time: Sunday, August 1, 2010 : 4:00 PM to 5:50 PM
• Sponsor: Section on Risk Analysis
• Author(s): Rhyne Woodrow Setzer*+
• Companies: U.S. Environmental Protection Agency
• Keywords: dose response ; hierarchical models ; benchmark dose

Abstract

The US EPA's N-Methyl Carbamate (NMC) Cumulative Risk Assessment was based on inhibition of acetylcholine esterase (AChE) activity through a common mechanism by 10 NMC pesticides through dietary, drinking water, and residential exposures, with the assumption that the effects of joint exposure to NMCs was dose-additive. The risk assessment used peak inhibition and the half-life of recovery from inhibition, which were estimated using dose-time-response modeling of animal studies, with multiple datasets for each chemical. The overall dose-time-response function was fit to the data using hierarchical non-linear models by approximate maximum likelihood. Relative potencies were calculated as ratios of doses estimated to result in 10% AChE inhibition, the benchmark dose. This work was reviewed by EPA and approved for publication but does not necessarily reflect official Agency policy.