Mortality range, toxicity tests

It is important to use different doses of a chemical or drug to evaluate chemical safety vis-a-vis skin toxicity. Dose levels to be tested for acute dermal toxicity in animals should be sufficient in number, (e.g., three or more and spaced appropriately to produce test groups with a range of toxic effects and mortality rates). The data should permit an acceptable determination of LD50. 

Exposure concentrations or chemical test dosages should be sufficient in number (at least three) and should be spaced appropriately. This should produce a range of toxic effects and mortality rates in animals. It also should help to draw a concentration mortality curve and permit an acceptable determination of LC50 values. In the case of potentially explosive test chemicals, care should be taken to avoid generation-explosive concentrations. However, for purposes of establishing suitable exposure concentration, a trial test is recommended. 

QSARs for the prediction of toxicity to aquatic organisms, including fish, invertebrates and algae, are relatively well developed for a broad range of chemical classes. More than 100 SARs for 55 chemical classes are available in a free, downloadable model called ECOSAR from the EPA website, based on test data and assumptions from test data. Aquatic toxicity endpoints include reproduction, growth and mortality, such as acute toxicity to fish, invertebrates, and algae. The PBT Profiler also estimates chronic toxicity to fish by means of the ECOSAR model it compares the fish chronic value to maximum water solubility, in order to estimate potential for aquatic risk. 

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