Transcript EA Engineering, Science, and Technology

Setting Standards: The Science of
Water Quality Criteria
Presented by: James B. Whitaker
Review of Annex 1 of the GLWQA
IJC Great Lakes Science Advisory Board
21 March 2001
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EA Engineering, Science,
and Technology
Introduction
Setting standards
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Standards are a necessity
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The ideal vs. the reality
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Introduction
Confusion introduced by terminology
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Water Quality Standards
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Water Quality Criteria
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Specific Objectives
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Guidelines
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Action Levels
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Introduction
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Do all of these terms mean the same
thing?
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Are the numerical values comparable?
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Can a single value be used for each
chemical?
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What is the best approach based on
current science?
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Water Quality Standards
Consist of two parts
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Designated Use
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Water Quality Criteria to protect that
use
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Water Quality Standards
Designated Uses
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Aquatic life
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Warm water/cold water
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Survival/propagation
Human Health
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Drinking/non-drinking
Wildlife
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Water Quality Standards
Designated Uses (continued)
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Recreation
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Agricultural
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Industrial
Existing vs. attainable uses
Use attainability analysis
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Water Quality Criteria
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Narrative: “No toxics in toxic
amounts”
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Numeric: Chemical concentrations to
protect designated uses
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Water Quality Criteria
Ohio WQC for Total Chromium (ug/l)
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Aquatic life (acute)
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Aquatic life (chronic)
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Human Health (drinking)
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Human Health (non-drinking)
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Agricultural
Annex 1 Specific Objective
1,800
86
140
14,000
100
50
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Water Quality Criteria
Three Components
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Magnitude (How much?)
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Duration (How long?)
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Frequency (How often?)
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Aquatic Life Criteria
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US EPA Guidelines
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Virtually unchanged since 1985
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Stringent data requirements (e.g., 8
families)
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Basis for GLWQG, most states
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Aquatic Life Criteria
Magnitude
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Protect 95th percentile most sensitive
species
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Acute and chronic criteria
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May be expressed as function of
water hardness, pH
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Aquatic Life Criteria
Key Drivers of Magnitude
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Acute toxicity of four most sensitive
species
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Number of species
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Acute-chronic ratio
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Aquatic Life Criteria
Duration
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Acute: 1-hour average
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Chronic: 4-day average
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How do these compare to actual
exposures in toxicity tests?
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Are these appropriate for all
chemicals?
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Aquatic Life Criteria
Frequency
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Once every three years
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Basis?
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Is it dependent on magnitude of
exceedance?
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Is this appropriate for all chemicals?
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Aquatic Life Criteria
Site-Specific Criteria
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Recalculation
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Water Effect Ratio
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Resident species
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Human Health Criteria
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US EPA Guidelines
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Updated in 2000
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Similar to GLWQC
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Carcinogens and non-carcinogens
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Human Health Criteria
Key Drivers of Magnitude
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Fish consumption rate
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BAF vs. BCF
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Cancer risk level
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Uncertainty factors
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Relative source contribution
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Human Health Criteria
Duration
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Lifetime (70 years)
Frequency
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Not expressed
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Wildlife Criteria
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Introduced in GLWQG
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Protect birds and mammals that
consume fish
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Similar to human health procedures
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Limited data, few criteria
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Emerging Criteria
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Aquatic life criteria for metals
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Dissolved
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Biotic Ligand Model
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Tier 2 “values”
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Nutrient criteria
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Tissue-based criteria
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Sediment criteria/guidelines
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Biocriteria
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Key Considerations for Deriving
Criteria
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What are you trying to protect?
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Appropriate and attainable uses
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Individuals or populations?
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What is actual exposure?
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What is “acceptable” level of risk?
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Where do criteria apply?
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Key Considerations for Deriving
Criteria
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National, regional, watershed, or sitespecific?
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What chemicals do you set criteria for?
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What do you do when minimum data
requirements are not met?
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How do you assess compliance?
Many of these are policy, rather than scientific
issues.
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Characteristics of “Quality” Criteria
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Robust
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Localized
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Based on extensive data base across range
of species to minimize effects of statistical
analyses and uncertainty factors
Appropriate for ecosystem and designated
use
Flexible
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Adjustable using reasonable site-specific
procedures
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