Description: The EPA Fathead Minnow Acute Toxicity database was generated by the U.S. EPA Mid-Continental Ecology Division (MED) for the purpose of developing an expert system to predict acute toxicity from chemical structure based on mode of action considerations. Hence, an important and unusual characteristic of this toxicity database is that the 617 tested industrial organic chemicals were expressly chosen to serve as a useful training set for development of predictive quantitative structure-activity relationships (QSARs). A second valuable aspect of this database, from a QSAR modeling perspective, is the inclusion of general mode-of-action (MOA) classifications of acute toxicity response for individual chemicals derived from study results. These MOA assignments are biologically based classifications, allowing definition of chemical similarity based upon biological activity instead of organic chemistry functional class as most commonly employed in QSAR study. MOA classifications should strengthen the scientific basis for construction of individual QSARs. However, it is cautioned that the broad MOA categorizations should not be construed to represent a single molecular mechanism; for example, CNS seizure agents and respiratory inhibitors are known to act through a variety of receptors. The DSSTox EPAFHM database includes information pertaining to organic chemical class assignments (ChemClass_FHM), acute toxicity in fathead minnow (LC50_mg), dose-response assessments (LC50_Ratio, ExcessToxicityIndex), behavioral assessments (FishBehaviorTest), joint toxicity MOA evaluations of mixtures (MOA_MixtureTest), and additional MOA evaluation of fish acute toxicity syndrome (FishAcuteToxSyndrome) in rainbow trout. All of these indicators, to the extent available, were considered in the determination of MOA and, additionally, were used to determine a level of confidence in the MOA assignment for each chemical (MOA_Confidence).
Number of Chemicals: 617