You are here:
ACUTE-TO-CHRONIC ESTIMATION (ACE V 2.0) WITH TIME-CONCENTRATION-EFFECT MODELS: USER MANUAL AND SOFTWARE
Citation:
Ellersieck, M. R., A. Asfaw, F L. Mayer Jr., G. F. Krause, K. Sun, AND G. Lee. ACUTE-TO-CHRONIC ESTIMATION (ACE V 2.0) WITH TIME-CONCENTRATION-EFFECT MODELS: USER MANUAL AND SOFTWARE. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-03/107, 2003.
Impact/Purpose:
The software program, Acute-to-Chronic Estimation (ACE), described herein, allows the user to estimate chronic toxicity for a species from raw acute toxicity data with accuracy and precision.
Description:
Ellersieck, Mark R., Amha Asfaw, Foster L. Mayer, Gary F. Krause, Kai Sun and Gunhee Lee. 2003. Acute-to-Chronic Estimation (ACE v2.0) with Time-Concentration-Effect Models: User Manual and Software. EPA/600/R-03/107. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL. 20 p.
Predictive toxicological models, including estimates of uncertainty, are necessary to address probability-based ecological risk assessments. Methods and software (ACE) were developed for estimating chronic toxicity from raw acute toxicity data (all response observations at all times and exposures). Three methods were developed - - Accelerated Life Testing (ALT), Multifactor Probit Analysis (MPA), and two-stage Linear Regression Analysis (LRA). Of the three, the method of choice is ALT, in that time to failure (death) of each experiment unit is independent. It requires three partial responses over the time period of acute testing, but will function with one. The MPA is a two dimensional probit analysis using both time and concentration to produce a multiple regression equation, however, each experimental unit is not independent. Also, the MPA requires more partial responses than the ALT. The LRA calculates LC values for each time period and then regresses the LC values as the Y axis and the reciprocal of time as the X axis. The Y intercept is the chronic no-effect concentration. The LRA will function when ALT and MPA fail; no partial responses are required. All methods provide confidence limits for the point estimates. The methods have previously been shown to estimate chronic no-effect concentrations very well when validated against actual paired acute and chronic test results with fishes.