This test determines the toxic effect of a substance to fish. For this species Brachidario rerio (zebrafish) which is exposed to the test substance for 96 hours, recording mortality at 24, 48, 72 and 96 hours, and determining the concentrations that kill 50% (LD50 is used: Lethal dose 50%). The test can be done in two ways: 1) Calculating LD50, in which case it takes place in two phases, a preliminary phase to determine the lethal approximate acute average concentration, and a second phase to determine the lethal concentration using a range of concentrations adjusted, depending on the findings of the preliminary phase; 2) Alternatively, one can determine the toxic effect of a substance fish, without actually determine the lethal concentration 50 (LD50), at concentrations chosen by the customer. In the test specimens of Brachidario rerio (zebrafish) of about 30 mm that are acclimatised for 7 days in the dilution water specially prepared for the test with a built salts they are used, and it must be measured throughout the test day, the concentration of dissolved oxygen, temperature, and pH. Test substances are dissolved in the dilution water. For substances with low aqueous solubility are pre - dissolved with ultrasonic devices or organic solvents with low toxicity to fish, in which case the corresponding controls toxicity of solvents to be included. In tests to calculate the 50% lethal dose (LD50) are used at least six groups with three fish in the first preliminary phase for determining the toxic range, and other 6 groups with at least seven fish in the second final step for calculating adjusted lethal concentration. In addition, a positive control with potassium dichromate tested with 7 fish should be included, so at least 67 fish are used. When low solubility substances are tested two additional controls are included to include assaying toxicity of the solvent used (14 fish), which is in this toxicity test with low solubility products totaling 81 fish. In tests to estimate the toxicity of certain specific concentrations, the number of fish is reduced by not having to evaluate the range of toxic concentrations. For testing, the laboratory must be provided the following information: interval of concentrations are to be assessed, in the case of having to calculate the LD50; concentrations to be tested in the case that only test specific desired concentrations (maximum 3 concentrations); nature of the product and its solubility; if insoluble in water, indicate what the organic solvent recommended.
Cost of the test: