1. Human Health & Aquatic Life Criteria
Cara Cowan Watts
Graduate Student
Biosystems Engineering

2. Source of Class Materials
Presentations and Handouts
adapted from
The U.S. EPA’s
Water Quality Standards Academy
November 27-December 1, 2006
Washington, DC

3. Human Health Criteria Expressed as a Pollutant Concentration Based on:
Toxicological Assessment
Exposure Scenario
Calculated for Ingestion of Aquatic Organisms Only and for Ingestion of Water and Organisms

4. Data Needed for HHC Toxicity Exposure Bioaccumulation factors (BAFs)
Toxic effects and dose-response properties
Risk Specific Doses for linear carcinogens
Point of Departure (POD) & Uncertainty Factor (UF) for nonlinear carcinogens
Reference dose (RfD) for noncarcinogens
Exposure
Site-specific BAFs or National BAFs
Trophic level data on accumulation of chemical in fish or shellfish
Bioaccumulation factors (BAFs)
Relative Source Contribution (RSC)
Exposure parameters: body weight (BW) drinking water intake (DI) and Fish Intake (FI)

5. Non-threshold Effects
All Levels of exposure pose some probability of an adverse response
Incremental risk levels can be calculated
EPA targets a risk level of one in one million (10-6)

6. Threshold Effects
Exposures to some finite value are expected to be without adverse effect on human health

7. Non-Cancer Dose Response Values
Reference Dose (RfD)
Estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to humans (including sensitive subgroups) that is likely to be without an appreciable risk of adverse effects during a lifetime
EPA’s Integrated Risk Information System (IRIS)

8. Non-Cancer Effects RfD Derivation Point of Departure
Point of Departure divided by Uncertainty Factor (UF)
Point of Departure
No Observed Adverse Effect Level (NOAEL)
Lowest Observed Adverse Effect Level (LOAEL)
Benchmark Dose (BMD)

9. Benchmark Dose Model

10. Uncertainty Factors Five areas of consideration
Intraspecies variation (UFH)
Interspecies variation (UFA)
Uncertainty due to the duration of study (UFS)
Uncertainty due to use of LOAEL (UFL)
Uncertainty due an inadequate database (UFD)
Invoked as integers of 1, 3, 10
3 is a half log10
Value selected determined by the data available
Usually ≤ 3,000

11. Non-Cancerous Effects
AWQC = RfD x RSC x [ ] BW
DI + (FI x BAF)
AWQC = Ambient Water Quality Criterion (mg/L)
RfD = Reference Dose (mg/kg-day)
RSC = Relative Source Contribution (%, to account for other sources of exposure)
BW = Human Body Weight (kg, 70 for average adult)
DI = Drinking Water Intake (L/day, 2 for average adult)
FI = Fish Intake (kg/day)
BAF = Bioaccumulation Factor (L/kg)

12. Carcinogen Dose-Response Values
Risk Specific Dose (RSD) for linear carcinogens
RSD is the acceptable risk Level divided by the Cancer Slope Factor
EPA recommends 10-6 (one in a million chance of cancer) but accepts the 10-5 risk level as long as highly exposed populations do not exceed 10-4 risk level
POD/UF approach for nonlinear carcinogens

13. Carcinogens Dose-Response

14. Linear Cancerous Effects
AWQC = RSD x [ ] BW
DI + (FI x BAF)
AWQC = Ambient Water Quality Criterion (mg/L)
RSD = Risk Specific Dose (mg/kg-day)
BW = Human Body Weight (kg, 70 for average adult)
DI = Drinking Water Intake (L/day, 2 for average adult)
FI = Fish Intake (kg/day)
BAF = Bioaccumulation Factor (L/kg)

15. Dose Response for Nonlinear Carcinogens

16. Nonlinear Cancer Effects
AWQC = POD/UF x RSC x [ ] BW
DI + (FI x BAF)
AWQC = Ambient Water Quality Criterion (mg/L)
POD/UF = Point of Departure/Uncertainty Factor (mg/kg-day)
RSC = Relative Source Contribution (to account for other sources of exposure)
BW = Human Body Weight (kg, 70 for average adult)
DI = Drinking Water Intake (L/day, 2 for average adult)
FI = Fish Intake (kg/day) = Bioaccumulation Factor (L/kg)
BAF = Bioaccumulation factor (L/kg)

17. Exposure Parameters
Assumes daily exposure over the course of a lifetime
Assigns mix of average values and high end values (e.g., 90th percentile) for exposure parameters such as ingestion rates and body weight
Derived to protect the majority of the general population

18. Default Exposure Parameters
Average adult body weight
BW = 70 kg
90th percentile estimate
DI = 2 L/day
FI = 17.5 g/day
Used by EPA for the national recommended water quality criteria when chronic health effects are of concern

19. Developmental Exposure Parameters
Women of childbearing age (ages 15-44), when fetal developmental effects are the most sensitive health endpoint
BW = 67 Kg
DI = 2 L/day
Children
BW = 30 Kg; ages 1-14
= 13 Kg; toddlers (ages 1-3)
= 7 Kg; infants
DI = 1 L/day for all sub-categories

20. Fish Intake Values For chronic health effects when targeting:
Recreational fishers = 17.5 g/day
Estimate of average consumption of freshwater/estuarine fish/shellfish;
Subsistence fishers = g/day
Estimate of average consumption of freshwater/estuarine fish/shellfish.
For developmental health effects when targeting:
Women of childbearing age (re: fetal effects) = g/day
Estimate of 90th percentile meal size of freshwater/estuarine fish/shellfish;
Children (ages 1-14) = g/day
Estimate of 90th percentile meal size of freshwater/estuarine fish/shellfish.

21. Relative Source Contribution
Accounts for exposures from sources other than water and freshwater/estuarine fish and shellfish ingestion
Inhalation for airborne sources
Consumption of food
Consumption of marine aquatic organisms
Not applied to linear carcinogens (i.e., those associated with a risk level)
Expressed as a percentage or subtracted, depending on the circumstances, from the RfD or nonlinear carcinogen

22. Bioaccumulation
Concentration in Tissue
Concentration in Water
BAF =

23. Aquatic Life Criteria Concentration of Exposure
Magnitude
Time Period of Exposure
Duration
Frequency of Exposure
How often (

24. Aquatic Life Criteria Types

25. CMC and CCC
CMC
Highest instream concentration of a toxicant to which organisms can be exposed for a brief period of time without causing an unacceptable adverse acute effect
CCC
Highest instream concentration of a toxicant to which organisms can be exposed for longer time periods without causing an unacceptable adverse effect
Final Chronic Value
Final Plant Value
Final Residue Value

26. Acute Toxicity Test 96-hour LC50 Concentration:
0.0 μg/L μg/L μg/L μg/L μg/L μg/L
Control
96-hr LC50 = 50 μg/L

27. Fathead Minnow Early Life Stage Test Growth Measured as Length
Chronic Toxicity Test
Fathead Minnow Early Life Stage Test
Growth Measured as Length
Concentration:
Control
0.0 μg/L μg/L μg/L μg/L μg/L μg/L
Length:
40 mm mm mm mm mm mm

28. Minimum Data Set: Freshwater Criteria Development
SALMONID
SECOND
FISH
FAMILY
CHORDATA
PLANKTONIC
CRUSTACEAN
BENTHIC
INSECT
ROTIFERA,
ANNELIDA,
MOLLUSCA
OTHER
INSECT OR

29. Sensitive Life Stages
Most Sensitive
Egg
Larva
Adult

30. Aquatic WQC Determination
Rank Genus Mean Acute Values
(GMAV) and Calculate the Percentile
of Each Rank (100 R/(N+1))
GMAV
Chronic Endpoints
Using the 4 Most Sensitive Genera,
Perform a Least Squares Regression
of the GMAV2 (log values) on the
Percentile Ranks (square roots)

31. Final Chronic Value
Perform Acute and Chronic testing using same species
in same dilution water
2. Use Results to Calculate Acute-Chronic Ratios (ACR)
Acute Value
Chronic Value
ACR =
3. Develop final Acute-Chronic Ratio (FACR) by taking
Geometric Mean of the appropriate Acute-Chronic Ratios
4. Calculate the Final Chronic Value (FCV) using the final Acute-Chronic Ratio
Final Acute Value
FACR
FCV =

32. Final Chronic Value Process
Are Data Available
from 8 Families?
Is Toxicity Related to a
WQ Characteristic?
Calculate Final
Chronic Equation
Yes
Yes No No
Use Calculation of FAV
Procedures To Calculate
Final Chronic Value
Calculate Species Mean
Acute-Chronic Ratios
Yes
Do Ratios Fit Any of the
4 Specified Cases in
Guidelines?
Calculate
Final Chronic Value:
Final Acute Value
Final Acute-Chronic
Ratio No
A Final Chronic Value
Cannot Be Calculated

33. Final Residue Value FRV = CCC CMC 4-Day Average 1-Hour Average
Maximum Permissable
Tissue Concentration
BCF or BAF
FRV =
Default Averaging Period for Freshwater and Saltwater
CCC
CMC
4-Day Average
1-Hour Average

34. Site Specific Criteria
Sensitivities of the site-species differ from the National Data Base
and/or
Physical/Chemical characteristics of the site alter the bioavailability or toxicity of the pollutant

35. Site Specific Criteria Procedures
Use Recalculation Procedure in Conjunction with Water-
Effect Ratio Procedure or Use Resident Species Procedure
If Physical or Chemical Properties at Site Affect Bioavailability
If Species at Site Are More or Less Sensitive
If Both of These Conditions Exist
Use Water-Effect Ratio Procedure or a Streamlined WER
Use Recalculation Procedure

36. Water Effect Ratios Site Water Toxicity Concentration WER =
Lab Water Toxicity Concentration
WER =
Site-Specific Criteria = WER x National Criteria

37. Questions?