1999 U.S. EPA Ammonia Criteria Technical Review Update

1
1999 U.S. EPA Ammonia CriteriaTechnical Review
Update
Basic Standards Workgroup September 10, 2004

• Prepared by
• Chadwick Ecological Consultants, Inc.

2
Ammonia Criteria Review

• What we found and how we got there
• Review conducted on behalf of Colorado Wastewater
  Utility Council
• Completed earlier analysis last fall
• We suggested new approaches
• Maybe too radical
• Back to more straightforward approach
• Council suggested we simply update EPA equations
  based on our
• Literature review results
• Data quality review

3
Derivation of Revised Criteria

• Technical Review
• Analysis of data used/not used by EPA
• Analysis of data analysis approaches
• Literature review for any new data
• There are lots of new data
• EPA did not conduct formal literature review for
  1999 update
• Reanalysis of criteria different approaches?
• Preliminary Results
• Review generally supports 1999 criteria as is
• But could update with new data/approaches

4
Updated EPA acute database

• Evaluate existing studies for appropriate use in
  deriving numerical water quality criteria
• Data quality review some bad datapoints, some
  odd decisions
• Removed gt or lt LC50 values from database
• Updated EPA acute toxicity database
• Literature review results
• Added 15 genera to the 34 in database (49 total)

5
Updated database, continued

• Recalculate SMAV and GMAV based on pH8 normalized
  data
• Could not specifically verify with and without
  salmonid derivation used by EPA
• Recommend warm and cold instead
• More supportable and representative
• Simply split dataset based on habitat types
  (i.e., cold water and warm water)

6
Final Acute Value (FAV) for the Cold Water
database

• Four most sensitive genera
• Prosopium (12.1 mg TA-N/L)
• Ceriodaphnia (14.2 mg TA-N/L)
• Oncorhynchus (20.0 mg TA-N/L)
• Salmo (23.7 mg TA-N/L)
• FAV 13.3 mg TA-N/L
• Did not override the FAV with large O. mykiss
  SMAV of 11.23 mg TA-N/L used by EPA
• value could not be substantiated

7
Final Acute Value (FAV) for the Warm Water
database

• Four most sensitive genera
• Fusconaia (1.3 mg TA-N/L)
• Lasmigona (2.8 mg TA-N/L)
• Medionidus (4.5 mg TA-N/L)
• Pyganodon (4.7 mg TA-N/L)
• FAV 2.8 mg TA-N/L
• All Unionidae clams (mussels)

8
Might Need to Reevaluate Revised Warm Water
Database.

• In fact, the eight most sensitive species in the
  revised warm water database are Unionid clams
• Considerable uncertainty regarding Unionidae
  presence or distribution within the State of
  Colorado
• Considerable uncertainty regarding Unionidae
  ammonia toxicity data
• So, split the warm water database into with and
  without Unionidae
• Both still meet eight family rule

9
Warm Water without Unionidae

• Four most sensitive genera
• Ceriodaphnia (14.2 mg TA-N/L)
• Notemigomus (14.7 mg TA-N/L)
• Gambusia (15.3 mg TA-N/L)
• Etheostoma (18.1 mg TA-N/L)
• FAV 14.8 mg TA-N/L

10

• Comparison of EPA Acute vs. Revised
• Acute Equations

Salmonids present
EPA Acute Equations
Salmonids absent
Revised Acute Equations
Cold-water
Warm-water without Unionidae
11

• Graphic comparison of EPA Acute vs. Revised Acute

12
Evaluation of EPA Chronic Database

• Limited chronic database
• We also updated chronic database
• Lit review and data quality
• Removed some data points added others
• No net change in size of chronic database
• EPA compelled to use one or two studies to
  derived CCC model
• EPA decided to include a seasonality component to
  protect presumed sensitive life stages of fish

13
Questions regarding EPA formulation of CCC

• Chronic database does not meet 8 family rule!
• For seasonality, incorporated the temperature
  slope from an acute ammonia toxicity study
• Same study used to show temperature not important
• Used Hyalella (amphipod) response slope for
  temperature relationship to represent with and
  without early life stage fish
• And the Hyalella data questionable due to poor
  control organism performance
• Built final equations using early life stage
  Lepomis and the Hyalella data

14
Alternate chronic approach

• Drop temperature component
• i.e., drop with and without early life stage
  approach since no data to support
• Either temperature effect or life-stage effect
• Revert to more common chronic criteria approach
  acute-to-chronic ratios
• Updated data provide ACR 4.7
• Apply to either EPA with and without salmonid
  equations or our cold, warm, warm w/o unionid
  equations

15
Comparison of EPA and CEC CCC

• Comparison of EPA Chronic and ACR chronic
• Similar at higher pH values
• EPA values generally less restrictive in cold
  water
• Diverge at mid-to-low pH
• especially in warm water

10
SM ACR 4.5
GM ACR 4.7
8
6
TA-N (mgN/L)
4
2
0
6.5
7.0
7.5
8.0
8.5
9.0
pH
CCC Fish ELS Present _at_ 24.6C
CCC Fish ELS Absent _at_ 24.6C
CCC Fish ELS Present _at_ 9C
CCC Fish ELS Absent _at_ 9C
CEC-CCC cold water
CEC-CCC warm water
CEC-CCC warm water w/o Unionids
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Acute Chronic
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So, whats next?!

• Keep existing EPA numbers?
• Modify acute?
• Rather than with and without salmonids, use
  cold and warm with and w/o unionids?
• Keep EPA chronic?
• Modify Chronic using acute-to-chronic ratio
  approach?
• Rather than with and without early life stages,
  use ACR adjusted acute equations