What is CMC?
A. The Criterion Maximum Concentration is often thought of synonymously as the “acute” Ambient Water Quality Criterion. CMC is an aqueous contaminant concentration not to be exceeded by 1-hour average concentration once every 3 years. It is calculated as one-half of the final acute value (FAV), which, in turn, is the fifth percentile of the set of the genus mean acute values (GMAV) for species representatives of at least eight animal families: two families in the phylum Chordata, one family in a phy- lum other than Arthropoda or Chordata, (either the Mysidae or Penaeidae family), and four other families.
