[1] The MATC is calculated and reported from the results of a number of standard procedures designed by the United States Environmental Protection Agency (US EPA) and other organizations to maintain high accuracy and precision among all toxicity tests for regulatory purposes.
In a toxicity test, the NOEC and LOEC are derived as a comparison from the negative control, or the experimental group that does not contain the chemical in question.
This type of toxicity test uses organisms in their most sensitive life stages, usually during times of early reproduction and growth, but not juveniles.
The ACR is useful for estimating an MATC for species in which only acute toxicity data exists, or for setting regulatory guidelines for the protection of aquatic life through water quality criteria by the US EPA.
[5] The CMC and CCC are two of the six parts of the aquatic life criterion under the WQC, and are the actual regulatory values for all priority pollutants tested.
The CMC is the highest concentration of a chemical in water that aquatic organisms can be exposed to acutely without causing an adverse effect.
Likewise, the CCC is the highest concentration of a chemical in water that aquatic organisms can be exposed to indefinitely without resulting in an adverse effect.
[6] The CWQG's long and short-term exposure concentrations are derived in a similar way as the methods used by the US EPA, and are the CMC or CCC equivalents.
Values derived from toxicity tests such as the MATC are reported to regulatory organizations like the US EPA and Environment Canada so more confident regulations can be designed.
[citation needed] Some common standard methods include those designed by the governmental organizations like Environment Canada, the US EPA, or the United States Food and Drug Administration (FDA).
[9] Because of these reasons, values that are derived through curve fitting methods, such as an LC50, or EC10 (the concentration that causes the measured effect in 10% of organisms) would be preferred if it was possible more often.