Aquatic Life CriteriaDevelopments Relevant to

Coal Mining

Charles DelosU.S. EPA, Office of Water

Health & Ecological Criteria DivisionSeptember 6, 2007

Three Topics:

New Copper Criterion

Selenium

Biological Criteria

Views are those of the author, not necessarily those of EPA.

Bioavailability-based Criterionfor Copper

Biotic Ligand Model2007

Compared toprevious hardness-based criterion,

the new BLM-based criterion may have:

– Higher value when Dissolved OrganicCarbon is high,

– Lower value when pH is low.

Selenium Toxicity

&

Aquatic Life Criteria Development

Selenium: bioaccumulationbut little or no biomagnification

• Algae and aquatic plants bioconcentrateselenium. Aquatic animals (further up thefood chain) receive nearly all of theirselenium from their diet, not directly fromwater.

• Exposure concentrations do not usuallychange significantly moving up the foodchain (in contrast to mercury).

Selenium Risk

• Species differences in sensitivity result indifferences in risk.

• In the field, effects have been observed infish and in birds.

• Mammals (including humans) appear to beless sensitive.

• Effects on invertebrates have notgenerally been the object of concern forselenium.

What are the threshold effects in fish?

• Deformities of offspring of excessivelyexposed adults:– Frequently observed in the field and in

combined field-lab tests.• Possible mortality of first year juveniles

over winter in cold climates.– Observed in one laboratory test (simulated

winter).– Not corroborated by field observations.– Subject of new toxicity testing by EPA.

Why did EPA opt for a fish tissuecriterion in its 2004 draft?

• The capacity for selenium bioaccumulationvaries from one water body to anotherbecause of differences in food webs.

• The same water concentration may yielddifferent degrees of fish tissueaccumulation and different degrees of riskin different water bodies.

• During implementation, a tissue criterionallows consideration of site-to-sitevariability in bioaccumulation.

What is the status of EPA criteria?

• Current criterion: 5 µg/L (water).– 1987 criterion relied on field observations of a

North Carolina impoundment.• 2004 draft: 7.9 µg/g (dry wt, fish tissue)

with 5.85 µg/g monitoring trigger value.• Currently re-evaluating to consider public

input and new data.– Due for publication late 2008.– Cannot predict the criterion value.

How much tissue-based datawere available for 2004 draft?

RotiferChinook salmonRainbow troutCutthroat troutBrook troutFathead minnow

Flannelmouth suckerRazorback suckerBluegill sunfishSunfish mixtureStriped bass

Aquatic species with chronic toxicity data:

Bluegill Chronic Toxicity TissueThresholds, parts per million

<5.85 – 7.9Lab> 17Mesocosm8.95Lab

12Mesocosm21 – 28Field

> 13Lab> 5.4Field

> 6.0Lab20 – 44Field

ValueTypeValueType

Site-Specific Effects Testing

• Obtain ripe adults from Se-contaminatedarea and reference area.

• Return to lab and fertilize eggs.• Culture eggs and larvae (further Se

exposure unnecessary).• Observe percentage of larvae with edema

or deformities (e.g., craniofacial and spinalmalformations).

Biological Criteria&

Tiered Aquatic Life Uses

Biological Criteria

• Biological Criteria are narrative or numericexpressions that describe the referencebiological integrity (structure and function)of aquatic communities inhabiting watersof a given designated aquatic life use.Biocriteria are based on the numbers andkinds of organisms present and areregulatory-based biologicalmeasurements.

Bio

logi

cal C

ondi

tion

The Biological Condition Gradient – Tiers

Increasing Levels of Stressors

Natural structure & function of biotic community maintained

Minimal changes in structure & function

Evident changes in structure andminimal changes in function

Moderate changes in structure &minimal changes in function

Major changes in structure &moderate changes in function

Severe changes in structure & function

1122

33

44

55

66

Ecological Attributes Evaluated ForEach Tier

Native taxa and non native taxa

Sensitive, intolerant taxa

Tolerant taxa

Condition (e.g. anomalies, parasites)

Ecosystem function (P/R ratios, decomposition,trophic level)

Ecosystem connectedness, temporal and spatialextent of effects

CaddisfliesCaddisflies

MayfliesMayflies

StonefliesStoneflies

Dragonflies and DamselfliesDragonflies and DamselfliesSensitive Organisms in Ohio Streams

Courtesy of Chris Yoder, CABB

MidgesMidgesLeechesLeeches

SnailsSnailsScudsScudsTolerant Organisms in Streams

Courtesy of Chris Yoder, CABB

BiologicalCondition

The Biological Condition Gradient

NaturalVariability

Increasing Level of Stressors

Minimal changes in structure & function

Evident changes in structure andminimal changes in function

Moderate changes in structure &minimal changes in function

Major changes in structure &moderate changes in function

Severe changes in structure & function

11 22

33

44

55

66

Natural structural, functional,and taxonomic integrity is

preserved.

A Tier 1 Communityin Maine

MidgesMidges

BeetlesBeetles

Dragonflies,Dragonflies,DamselfliesDamselflies

CaddisfliesCaddisflies

MayfliesMayflies

StonefliesStoneflies

1 inch

Courtesy of Susan Davies, ME DEP

BiologicalCondition

The Biological Condition Gradient

NaturalVariability

Increasing Level of Stressors

Natural structure and function of biotic community maintained

Minimal changes in structure & function

Evident changes in structure andminimal changes in function

Moderate changes in structure &minimal changes in function

Major changes in structure &moderate changes in function

Severe changes in structure & function

1122

3344

55

66

Evident changes instructure due to loss ofsome rare native taxa;shifts in relativeabundance; ecosystemlevel functions fullymaintained throughredundant attributes ofthe system.

CaddisfliesCaddisflies

StonefliesStoneflies

MayfliesMayfliesBlackflies

MidgesMidges

Non-insectsNon-insects

Crane flies

Beetles

A Tier 3 Community

1 inchCourtesy of Susan Davies, ME DEP

BiologicalCondition

The Biological Condition Gradient

NaturalVariability

- - No Effect - -

Natural structure and function of biotic community maintained

Minimal changes in structure & function

Evident changes in structure andminimal changes in function

Moderate changes in structure &minimal changes in function

Major changes in structure &moderate changes in function

Severe changes in structure & function

1122

33

44

66Extreme changes in structure;

wholesale changes in taxonomiccomposition; extreme alterationsfrom normal densities; organism

condition is often poor; anomaliesmay be frequent; ecosystem

functions are extremely altered.

A Tier 5-6 Community

CaddisfliesCaddisflies

SnailsSnails

MidgesMidges

LeechesLeeches

ScudsScuds

BeetlesBeetlesCranefliesCraneflies

1 inch

Courtesy of Susan Davies, ME DEP

Bio

logi

cal C

ondi

tion

The Biological Condition Gradient – Tiers

Increasing Levels of Stressors

Natural structure & function of biotic community maintained

Minimal changes in structure & function

Evident changes in structure andminimal changes in function

Moderate changes in structure &minimal changes in function

Major changes in structure &moderate changes in function

Severe changes in structure & function

1122

33

44

55

66