Bayesian Approach to Estimating Reproductive Inhibition Potency in Aquatic Toxicity Testing

• Activity Number: 41
• Type: Contributed
• Date/Time: Sunday, July 29, 2012 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics and the Environment
• Author(s): Jing Zhang*+ and A. John Bailer and James T. Oris
• Companies: Miami University and Miami University and Miami University
• Keywords: Bayesian Hierarchical Models ; Reproductive Toxicology ; Historical Control Information ; Ceriodaphnia dubia

Abstract

Effectively and accurately assessing the toxicity of chemicals and their impact to the environment continues to be an important concern in ecotoxicology. Single experiments conducted by a particular laboratory often serve as the basis of toxicity risk assessment. These laboratories often have a long history of conducting experiments using particular protocols. In the present study, a Bayesian analysis for estimation of potency based on a single experiment was formulated, which then served as the basis for incorporating the experimental information from historical controls. A Bayesian hierarchical model was developed to estimate the reproductive inhibition concentrations (RIp) of a toxicant and flexible ways of using historical control information were suggested. The methods were illustrated using a data set produced by the test for reproduction in Ceriodaphnia dubia in which the number of young produced over three broods was recorded. Incorporating historical control information in the Bayesian hierarchical model results in potency estimates that are more precise compared to frequentist methods.