technical challenges in the development of the clark fork river ecological risk assessment dale j....

Technical Challenges in Technical Challenges in the Development of the the Development of the

Clark Fork River Ecological Clark Fork River Ecological Risk AssessmentRisk Assessment

Dale J. Hoff, Ph.D.Dale J. Hoff, Ph.D.

Region VIII, USEPARegion VIII, USEPA

BTAG CoordinatorBTAG Coordinator

Clark Fork River Ecological Clark Fork River Ecological Risk AssessmentRisk Assessment

Not Here to talk about the Results of Not Here to talk about the Results of the Assessment as much as to the Assessment as much as to discuss technical aspects of multiple discuss technical aspects of multiple debatesdebates

IMPORTANT: NEED to acknowledge IMPORTANT: NEED to acknowledge the incredible support that this the incredible support that this project received from ORD: Drs. project received from ORD: Drs. Erickson, Stephan and Mount from Erickson, Stephan and Mount from the Duluth Effects Lab.the Duluth Effects Lab.

Multiple Lines of Evidence were used Multiple Lines of Evidence were used to Answer Questions of Aquatic Riskto Answer Questions of Aquatic Risk

Weight of Evidence ApproachWeight of Evidence Approach– Predictive approach:Predictive approach:

HQ= Site exposure / Reference ExposureHQ= Site exposure / Reference Exposure

– Site-Specific Toxicity TestsSite-Specific Toxicity Tests WER Ratio tests……WER Ratio tests…… caged fish studiescaged fish studies dietary exposure studiesdietary exposure studies

– Direct Observations of Receptor Direct Observations of Receptor DemographicsDemographics

Major Findings from the Major Findings from the CFRERACFRERA

Impacts to the Aquatic Community as a Impacts to the Aquatic Community as a Whole from As, Cd, Cu, Pb and ZnWhole from As, Cd, Cu, Pb and Zn– Comparison of AWQC values to Total and Comparison of AWQC values to Total and

Dissolved MetalsDissolved Metals– Total and Dissolved metals concentrations Total and Dissolved metals concentrations

compared to both acute and chronic criteriacompared to both acute and chronic criteria Total recoverable concentrations of all metals Total recoverable concentrations of all metals

exceeded AWQCexceeded AWQC Dissolved concentrations of only Cu exceeded Dissolved concentrations of only Cu exceeded

Chronic and Acute occasionallyChronic and Acute occasionally


Impacts to Salmonids Impacts to Salmonids – Predictive: Few, < 10 out of 232 exceed Predictive: Few, < 10 out of 232 exceed

salmonid surface water toxicity reference valuesalmonid surface water toxicity reference value– Toxicity tests: Toxicity tests completed by PRP Toxicity tests: Toxicity tests completed by PRP

and supported by trustee results for respiratory and supported by trustee results for respiratory exposure were used to derive site specific exposure were used to derive site specific surface water TRVs, 2 out of 232 exceeded surface water TRVs, 2 out of 232 exceeded chronic, O exceeded Acute.chronic, O exceeded Acute.

– Demographics: 2 replicates (multiple years) of Demographics: 2 replicates (multiple years) of 15 stations consistently had less fish on CFR 15 stations consistently had less fish on CFR compared to Referencecompared to Reference


Other Toxicity tests on SalmonidsOther Toxicity tests on Salmonids– Trout Feeding StudiesTrout Feeding Studies

Conflicting results led to multiple analyses to Conflicting results led to multiple analyses to reduce uncertainty. Oral TRVs were used from the reduce uncertainty. Oral TRVs were used from the lowest concentrations leading to effects lowest concentrations leading to effects (Woodward et al ). Very few exceedences occurred (Woodward et al ). Very few exceedences occurred of little magnitude and only in the upper reachesof little magnitude and only in the upper reaches

Tissue burdens in fish leading to effects in growth Tissue burdens in fish leading to effects in growth from other pathways of exposure were used to from other pathways of exposure were used to help support site-specific TRV. help support site-specific TRV.

– Conclusion:Conclusion: supported decrease in demographics were supported decrease in demographics were more a result of Acute, not chronic exposuremore a result of Acute, not chronic exposure


Other Toxicity tests on SalmonidsOther Toxicity tests on Salmonids– Caged fish studiesCaged fish studies

Hatchery fish were placed in cages in the river Hatchery fish were placed in cages in the river during spring flow. during spring flow.

No apparent or statistical correlation between No apparent or statistical correlation between ambient, measured levels of total recoverable ambient, measured levels of total recoverable and survival were noted, and survival were noted,

Survival and growth were decreased on the CFR Survival and growth were decreased on the CFR compared to referencecompared to reference

– ConclusionConclusion: : Caged fish studies support Acute Caged fish studies support Acute exposures more than chronic exposures resulting in exposures more than chronic exposures resulting in effects.effects.


Other Toxicity tests on SalmonidsOther Toxicity tests on Salmonids– Flow through Mobile Laboratory testFlow through Mobile Laboratory test

Multiple life stages of trout exposed to dilutions Multiple life stages of trout exposed to dilutions of CFR water and survival of eggs, swim-ups, of CFR water and survival of eggs, swim-ups, and frys monitored. Water concentrations of and frys monitored. Water concentrations of metals quantified every 4 hrs for 6 weeks during metals quantified every 4 hrs for 6 weeks during spring runoff.spring runoff.

No difference among any endpoints and any No difference among any endpoints and any dilutions. No high spikes from low-flow runoff dilutions. No high spikes from low-flow runoff year were noted.year were noted.

– ConclusionsConclusions: Supportive of acute risks, not chronic : Supportive of acute risks, not chronic risksrisks


Other Toxicity tests on SalmonidsOther Toxicity tests on Salmonids Non-lethal Endpoints Non-lethal Endpoints

– BiomarkersBiomarkers MetallothioneinMetallothionein lipid peroxidaselipid peroxidase Clinical Pathology: liver enzymes, Blood Cell Clinical Pathology: liver enzymes, Blood Cell

counts, etccounts, etc– AvoidanceAvoidance

Laboratory avoidance is most likely real at Laboratory avoidance is most likely real at concentrations as low as 1 ppb dissolved Cu.concentrations as low as 1 ppb dissolved Cu.

– UncertaintyUncertainty: Evidence of exposure, not effects, : Evidence of exposure, not effects, principally in laboratory only, little concurrent principally in laboratory only, little concurrent evidence of exposure and effects in the field.evidence of exposure and effects in the field.


Impacts to Benthic InvertebratesImpacts to Benthic Invertebrates– Predictive:Predictive: Some species should be impacted Some species should be impacted

based off of Daphnia toxicity valuesbased off of Daphnia toxicity values– Toxicity testsToxicity tests: Sediment, SEM-AVS, pore-: Sediment, SEM-AVS, pore-

water analyses demonstrate and predict water analyses demonstrate and predict toxicity in upper portionstoxicity in upper portions

– DemographicsDemographics: A 12 yr data set collected by : A 12 yr data set collected by the same observer in the same locations the same observer in the same locations consistent with finding that sensitive species consistent with finding that sensitive species are limited, but biomass unaffectedare limited, but biomass unaffected


Impacts to Benthic InvertebratesImpacts to Benthic Invertebrates– statistical correlation between water statistical correlation between water

concentrations, not sediment, and tissue concentrations, not sediment, and tissue concentrations positiveconcentrations positive

– statistical correlation between water statistical correlation between water concentrations, not sediment, and species concentrations, not sediment, and species richness and EPT indexs were positive.richness and EPT indexs were positive.

ConclusionsConclusions: All three lines of evidence not consistent : All three lines of evidence not consistent with a large magnitude of chronic risk to COMMUNITY, with a large magnitude of chronic risk to COMMUNITY, principle pathway was through the water, not principle pathway was through the water, not sediment.sediment.


Impacts to AlgaeImpacts to Algae– Predictive: Few exceedences of Predictive: Few exceedences of

Surface water TRVSurface water TRV– Toxicity tests: no direct toxicity Toxicity tests: no direct toxicity

studies availablestudies available– Demographics: Algal populations are Demographics: Algal populations are

the same as reference stream.the same as reference stream. Conclusion:Conclusion: Algal populations on the CFR are not Algal populations on the CFR are not

impacted by metalsimpacted by metals

How can the following How can the following observations be concurrently observations be concurrently

occurring?occurring?

Trout population (k-Trout population (k-selected, top level selected, top level predator) be decreased predator) be decreased up to 6 foldup to 6 fold

Only the most metals Only the most metals sensitive species of sensitive species of Benthics be decreased Benthics be decreased (k- and r- selected)(k- and r- selected)

Algal populations (r-Algal populations (r-selected) not impactedselected) not impacted

Nearly random Nearly random storm events in storm events in time and space time and space prevent learned prevent learned protective protective behavior behavior

r-selected species r-selected species can reproduce can reproduce exponentially after exponentially after acute eventsacute events

Theoretical population Theoretical population relationship among exposure relationship among exposure

and effectsand effectsP

opu

lati

on E

stim

ate

(n)

Time of n Estimate

Time of AcutePulse Event

Time

Trout

Benthics

Algae


Impacts to the Aquatic CommunityImpacts to the Aquatic Community– Risks to aquatic species are apparent from Risks to aquatic species are apparent from

multiple lines of evidencemultiple lines of evidence– Risks are principally from acute exposure Risks are principally from acute exposure

during storm eventsduring storm events– Risks from non-lethal chronic exposures are of Risks from non-lethal chronic exposures are of

probable little consequence to receptors as probable little consequence to receptors as exposures are of neither of sufficient duration exposures are of neither of sufficient duration or magnitude to impact or magnitude to impact growth………………..but…..uncertaintly growth………………..but…..uncertaintly precludes total exclusion of chronic risks.precludes total exclusion of chronic risks.


Soil organisms---weight of evidenceSoil organisms---weight of evidence– Predicted: Predicted: risk is occurring and could be risk is occurring and could be

widespread, depending on what widespread, depending on what benchmark value is usedbenchmark value is used

– Toxicity experimentsToxicity experiments: microbes and : microbes and earthworms are affected in slickens earthworms are affected in slickens areasareas

– Population SurveysPopulation Surveys:: Limited information Limited information


Plants--- weight of evidencePlants--- weight of evidence– Predictive:Predictive: Many soil samples had heavy metal Many soil samples had heavy metal

levels greater than those found to have effects in levels greater than those found to have effects in other conditionsother conditions

– Toxicity ExperimentsToxicity Experiments: tests from soils on the site : tests from soils on the site has found them to be toxic to at least some has found them to be toxic to at least some plants. plants.

– Population SurveysPopulation Surveys: Decreased number of : Decreased number of different types of plants (species richness)different types of plants (species richness)

NotesNotes– impossible to consider metals effects without impossible to consider metals effects without

pH--acid soil is harmful to plantspH--acid soil is harmful to plants– Risk outside slickens areas is lowerRisk outside slickens areas is lower


Wildlife--- weight of evidenceWildlife--- weight of evidence– Predictive: Predictive: Risks highest to small organisms Risks highest to small organisms

that eat insects that eat insects – Toxicity experimentsToxicity experiments: no info: no info– Population SurveysPopulation Surveys: Frequency of sign for : Frequency of sign for

raccoon, mink, and otter was significantly raccoon, mink, and otter was significantly less on the Clark Fork River compared to the less on the Clark Fork River compared to the Big Hole RiverBig Hole River

NotesNotes: Conclusions are uncertain because of : Conclusions are uncertain because of the lack of direct measurements and evidence the lack of direct measurements and evidence of exposure and toxicity.of exposure and toxicity.


Which metals are of most concern Which metals are of most concern for terrestrial speciesfor terrestrial species– Varies for each speciesVaries for each species

PlantsPlants: best estimate is the sum of all : best estimate is the sum of all metals in conjunction with pH best metals in conjunction with pH best predict effects in the fieldpredict effects in the field

Microbes and wormsMicrobes and worms: Copper and Arsenic : Copper and Arsenic primarilyprimarily

WildlifeWildlife: Arsenic, cadmium and lead: Arsenic, cadmium and lead


Impacts to the terrestrial systemImpacts to the terrestrial system– Risks to vegetation and soil invertebrates Risks to vegetation and soil invertebrates

associated with pH and exposed associated with pH and exposed “slickens” tailings areas“slickens” tailings areas

– Risks to wildlife predicted but highly Risks to wildlife predicted but highly uncertainuncertain

Conclusions:Conclusions: Risks focussed around Risks focussed around the upper portions of the river, in and the upper portions of the river, in and around exposed tailings...around exposed tailings...


Common Themes among systems:Common Themes among systems:– 1. “Slickens”, exposed tailings bad for both 1. “Slickens”, exposed tailings bad for both

aquatic and terrestrial species.aquatic and terrestrial species.– 2. Chronic risks of relatively little concern, 2. Chronic risks of relatively little concern,

absolute risk immeasurable compared to absolute risk immeasurable compared to potential impacts from acute exposures (> potential impacts from acute exposures (> 500,000 ppb dissolved Cu flowing into river)500,000 ppb dissolved Cu flowing into river)

– 3. Focus of remedial action should be on 3. Focus of remedial action should be on “Slickens”, to prevent acute exposures in “Slickens”, to prevent acute exposures in Aquatic system and decrease bioavailability of Aquatic system and decrease bioavailability of metals in terrestrial system.metals in terrestrial system.

Feasibility StudyFeasibility Study

Clearly, the focus for remedial Clearly, the focus for remedial action is on areas of exposed action is on areas of exposed tailingstailings

Secondarily, answering questions Secondarily, answering questions about the feasibility of addressing about the feasibility of addressing chronic riskschronic risks

How to resolve issues ?How to resolve issues ?

1. USE GOOD SCIENCE !!1. USE GOOD SCIENCE !!– Doesn’t always make people feel good, Doesn’t always make people feel good,

but puts forth the evidence in a logical but puts forth the evidence in a logical manner and provides the Agency with manner and provides the Agency with the most defensible document for the most defensible document for enforcement actionsenforcement actions

2. Weight of Evidence to objectively 2. Weight of Evidence to objectively describe strengths and weaknesses describe strengths and weaknesses of given issuesof given issues

Significant IssuesSignificant Issues

Burden of ProofBurden of Proof– what is threshold for saying an effect what is threshold for saying an effect

is likely. is likely. Significant Ecological EffectSignificant Ecological Effect

– lethal vs. non-lethallethal vs. non-lethal– growth vs. biomarkergrowth vs. biomarker– individual vs. a populationindividual vs. a population– population vs. a communitypopulation vs. a community

Significant IssuesSignificant Issues

Use of Water Effect Ratio testing in Use of Water Effect Ratio testing in the Risk Assessmentthe Risk Assessment

WER = Ratio of Site Water Toxicity and Lab water

LD50 = 300 ug/L Cu (site water)150 ug/L Cu (lab water)

WER = 2

Use of Water Effect Ratio Testing Use of Water Effect Ratio Testing in CERCLA Risk Assessmentsin CERCLA Risk Assessments

ProsPros– Site-specifice toxicity Site-specifice toxicity

teststests– relative toxicity to relative toxicity to

literature values tested literature values tested directlydirectly

– relative toxicity can be relative toxicity can be measured throughout measured throughout the yearthe year

– data from multiple data from multiple species requiredspecies required

– Established protocols Established protocols must be usedmust be used

ConsCons– Some specifics of the Some specifics of the

test proceduretest procedure– Differences on toxicity Differences on toxicity

from the influence of from the influence of Ca (lab) and Mg (field)Ca (lab) and Mg (field)

– Influence from Influence from multiple metalsmultiple metals

– Ongoing remedial Ongoing remedial action will influence action will influence WER ResultsWER Results

Use of Water Effect Ratio Testing Use of Water Effect Ratio Testing in CERCLA Risk Assessmentsin CERCLA Risk Assessments Resolution (The Duluth EP - A team)Resolution (The Duluth EP - A team)

– Use of Raw data to establish site-specific Use of Raw data to establish site-specific thresholds of toxicity……forgot about an thresholds of toxicity……forgot about an adjustment factoradjustment factor

Final equation for Acute number Final equation for Acute number (Normalized to a 0.4 g fish):(Normalized to a 0.4 g fish):– Log (LC50)=1.478 + 0.505 x log Log (LC50)=1.478 + 0.505 x log

(Calcium/10) +0.398 x log (DOC) - 0.391 (Calcium/10) +0.398 x log (DOC) - 0.391 x log (Calcium / 10) x log (DOC)x log (Calcium / 10) x log (DOC)


Points of InterestPoints of Interest– Mass significantly influenced LC50 estimate Mass significantly influenced LC50 estimate

(0.4 g is the most sensitive mass, smaller (0.4 g is the most sensitive mass, smaller and larger fish less sensitive)and larger fish less sensitive)

– Ca/Mg ratio more important than Hardness Ca/Mg ratio more important than Hardness estimate for the influence of toxicityestimate for the influence of toxicity

– DOC also influences the toxicityDOC also influences the toxicity– Need to use river water in same system, but Need to use river water in same system, but

outside the OU to establish credible outside the OU to establish credible relationships.relationships.


ORD Research Need ?ORD Research Need ?– Not basic research, but important to Not basic research, but important to

programsprograms– What other criteria would benefit from What other criteria would benefit from

weight adjustment/normalization?weight adjustment/normalization?– What is the relative importance of What is the relative importance of

different salts (measured as calcium different salts (measured as calcium carbonate equivalents) in their role on carbonate equivalents) in their role on mediating the toxicity of metals in water? mediating the toxicity of metals in water?

Trout Feeding StudiesTrout Feeding Studies

Pathway is realPathway is real Uncertainties around current studies:Uncertainties around current studies:

– Bioavailability: Bioavailability: Topically applied metals to trout chow vs. ground Topically applied metals to trout chow vs. ground

up benthics from the fieldup benthics from the field Multiple metal mixtures. One metal influencing the Multiple metal mixtures. One metal influencing the

uptake of other metalsuptake of other metals

– Confounding factors:Confounding factors: nutritional problems from benthic studiesnutritional problems from benthic studies food matrix leading to gut impaction not related to food matrix leading to gut impaction not related to

metals exposuremetals exposure

Trout Feeding StudiesTrout Feeding Studies

UncertaintiesUncertainties– If have a TRV, what matrix do you If have a TRV, what matrix do you

compare it to.compare it to. Swim-up fry do not eat large mayflys, Swim-up fry do not eat large mayflys,

caddisflys etc.caddisflys etc. what is the geographical representation of what is the geographical representation of

whatever matrix is measured ? whatever matrix is measured ?

– No from natural organism exposure (ie, No from natural organism exposure (ie, not trout chow) has ever demonstrated a not trout chow) has ever demonstrated a consistent dose-response.consistent dose-response.

Trout Feeding StudiesTrout Feeding Studies ORD Research Need ?ORD Research Need ?

– 1. What techniques can be used to quantify 1. What techniques can be used to quantify wild fry diets?wild fry diets?

– 2. What are the diets?2. What are the diets?– 3. What factors influence bioavailability of 3. What factors influence bioavailability of

the metals in the fish gut?the metals in the fish gut?– 4. What factors need to be considered in 4. What factors need to be considered in

designing a study around dietary exposure?designing a study around dietary exposure?– 5. What standard procedures can be 5. What standard procedures can be

developed to prevent confounding factorsdeveloped to prevent confounding factors

Non-lethal EndpointsNon-lethal Endpoints

BiomarkersBiomarkers– Hypothesis is that responses by enzymatic Hypothesis is that responses by enzymatic

biomarkers influence overall healthbiomarkers influence overall health Principle mechanism is energy transfer to protein Principle mechanism is energy transfer to protein

synthesis of biomarker away from growth related synthesis of biomarker away from growth related expendituresexpenditures

Examples: Metallothioneins, lipid peroxidase, Examples: Metallothioneins, lipid peroxidase, Clinical pathologyClinical pathology

ORD Question: Is there any relationship ORD Question: Is there any relationship between growth and biomarker responsebetween growth and biomarker response


ORD Research for biomarkers??ORD Research for biomarkers??– Is there any relationship between Is there any relationship between

growth and biomarker response?growth and biomarker response?– Is there any relationship between Is there any relationship between

growth effects and population growth effects and population decline?decline?

– Is there a threshold level of biomarker Is there a threshold level of biomarker response that adds concern of response that adds concern of effects ?effects ?

Non-lethal EndpointsNon-lethal Endpoints Avoidance BehaviorAvoidance Behavior

– Avoidance behavior of trout to metals has been Avoidance behavior of trout to metals has been found repeatedly in laboratory settings.found repeatedly in laboratory settings.

– Concentrations as low as 1 ppb Cu has caused Concentrations as low as 1 ppb Cu has caused avoidance in laboratoryavoidance in laboratory

– Applicability of laboratory data is called into Applicability of laboratory data is called into question in the fieldquestion in the field

– Only examples of field avoidance behavior are Only examples of field avoidance behavior are at surface water metal concentrations well at surface water metal concentrations well above those of chronic and even acute criteria!above those of chronic and even acute criteria!


Avoidance BehaviorAvoidance Behavior– ORD Research:ORD Research:

What other factors besides metals are What other factors besides metals are quantifiably important in avoidance behavior quantifiably important in avoidance behavior

– (cover, food, etc)(cover, food, etc) What relative importance is avoidance level What relative importance is avoidance level

concentrations in reference to other concentrations in reference to other endpoints in the wild?endpoints in the wild?

What magnitude of avoidance must occur What magnitude of avoidance must occur before population level impacts are seen?before population level impacts are seen?


and effectsand effectsP

opu

lati

on E

stim

ate

(n)

Time of n Estimate

Time of AcutePulse Event

Time

Trout

Benthics

Algae


and effectsand effects

Multi-component community Multi-component community analysis?analysis?

Can better decisions be made by Can better decisions be made by looking at multiple levels?looking at multiple levels?

Much work has been done on Much work has been done on Benthic communities, but how do Benthic communities, but how do they fit into the bigger picture?they fit into the bigger picture?

Wildlife WorkWildlife Work

I did not think I would have a lot of I did not think I would have a lot of time to go into these issues, but time to go into these issues, but there are many, many more research there are many, many more research questions related to wildlife toxicity.questions related to wildlife toxicity.– Principle questions revolve around Principle questions revolve around

bioavailabilitybioavailability What factors are the most important to What factors are the most important to

consider in the absorption of metals in consider in the absorption of metals in different species?different species?

ORD input into Superfund Risk ORD input into Superfund Risk Assessment: A Regional Assessment: A Regional

PerspectivePerspective

Unfortunately………most of need is Unfortunately………most of need is NOT basic researchNOT basic research

Fortunately……….most of pragmatic Fortunately……….most of pragmatic need can be met through need can be met through coordination of regional scientists coordination of regional scientists with basic research questionswith basic research questions

Example of Mount study: Use of CFR Example of Mount study: Use of CFR sediment in new trout feeding study.sediment in new trout feeding study.


PerspectivePerspective Follow up on basic research important for Follow up on basic research important for

applications in the Region.applications in the Region.– Erickson’s paper on dissolved vs. total metalsErickson’s paper on dissolved vs. total metals– Believe it or not: Unscrupulous scientists will Believe it or not: Unscrupulous scientists will

intentionally misuse your DATA!!!!intentionally misuse your DATA!!!!– Briefings through videoconference to primary Briefings through videoconference to primary

program contacts (such as BTAG coordinators program contacts (such as BTAG coordinators in Superfund) can help insure appropropriate in Superfund) can help insure appropropriate use of ORD data and methods.use of ORD data and methods.


PerspectivePerspective Remember that often what is boring to you Remember that often what is boring to you

all is NEWS to us!!!!all is NEWS to us!!!! ORD needs to continue original research ORD needs to continue original research

with ideas that are new and NOT necessarily with ideas that are new and NOT necessarily applied.applied.

However, all new research is built on old However, all new research is built on old concepts. If sites can be used for new work, concepts. If sites can be used for new work, all the better. all the better.

Don’t forget about regional scientists as a Don’t forget about regional scientists as a source of ideas and even labor!!source of ideas and even labor!!

technical challenges in the development of the clark fork river ecological risk assessment dale j....

Documents

n survival

cfrera n impacts

fish studies n hatchery

studies n conflicting

chronic exposure slide

reference slide

major findings

upper reaches n tissue