Water: Water Quality Standards Academy
Education & TrainingTraining ProgramsWater Quality Standards AcademyPreparation for Deriving the CCC: Approach Based on Available DataPreparation for Deriving the CCC: Approach Based on Available Data
Course Navigation
- Listing Impaired Waters and Developing TMDLs
- Monitoring & Assessment
- NPDES Permit Program
- Human Health Ambient Water Quality Criteria
- Aquatic Life Criteria
- EPA's Role
- Two Concentration-Related Criteria
- Steps in Deriving the Criteria
- Prioritizing Chemicals
- Collecting Effects Data
- Assessing Acute Effects Data
- Calculate the GMAVs
- Rank the GMAVs
- Calculate the FAV
- From FAV to CMC
- Factoring in Water Characteristics
- CCC Approach Based on Available Data
- Assessing Chronic Effects Data
- CCC Calculation of the FCV
- FCV to CCC
- Criteria Review Process
- Site-Specific Criteria
- Summary
- Quiz
Basic Course: Supplemental Topics
For deriving the Criterion Continuous Concentration (or Chronic Criterion), the 1985 Guidelines call for using the same procedure as the one described above to derive the CMC (or acute criterion) when sufficient data are available. That is, if chronic values are available for at least eight families with the required taxonomic diversity, the CCC is set to the fifth percentile of the Genus Mean Chronic Values (GMCVs) in the same way the FAV for the CMC is calculated from GMAVs.
Often, however, available chronic toxicity test data are insufficient to meet the guidelines’ minimum requirements—because chronic toxicity tests take longer to carry out and thus are more expensive than acute effects testing. For such situations, the 1985 Guidelines provide an alternate way to derive a chronic criterion by using ratios derived from studies in which both acute and chronic tests have been conducted simultaneously for the same species.
