Substantial Reduction of Uncertainty in a Baseline ERA after...

Department of Zoology/National Food Safety and Toxicology CenterMichigan State University

Substantial Reduction of Uncertainty in a Baseline ERA after Application of Site-Specific Data

Matt J. Zwiernik, Ph.D.John P. Giesy, Ph.D.Alan L. Blankenship, Ph.D.Paul D. Jones, Ph.D.K. Kannan, Ph.D.Denise Kay, Ph.D.Cyrus Park, B.S.Stephanie Pastva, M.S.Karl Strause, M.S.Arianne Neigh, B.S.Monica MacCarroll, B.S.Ryan Holem, B.S.

Aquatic Toxicology Laboratory


Kalamazoo River ProjectDesigned to address the effects of uncertainties in a

Baseline Risk Assessment• Site-specific PCB exposures

– Congener specific PCB analysis– Dietary composition– PCB concentration in dietary items– Compare exposure to dietary effect levels (TRVs)– Site use

• Receptor tissue concentrations• Measure receptor health (e.g., productivity and other relevant

endpoints)


Examining the Risk Assessment DogmaUncertainty and Conservative Bias : Reality

• 1993: State of Michigan and PRPs agreed upon the scope of data to be collected for a site-specific wildlife ERA for the Kalamazoo River area of concern

• 1993-95: Biota outlined in the sampling plan were collected and analyzed

• 1999: A combination of site-specific and modeled data was used to develop the “Site-specific Baseline ERA”

• 2000-2004: MSU-ATL has been conducting a multi-year comprehensive site-specific risk of harm evaluation for wildlife receptors on the Kalamazoo River.


Kalamazoo River Area of Concern


Kalamazoo Area of Concern

•130 km of river from the city of Kalamazoo to Lake Michigan

•Alternating series of free flowing sections and impoundments formed by six dams

•Three of the dams have been removed to their sill levels, exposing approximately 205 ha of former sediments as floodplain soils


Kalamazoo Area of ConcernContaminant Issues: PCBs

•Five paper mills between the cities of Kalamazoo and Plainwell

•A majority of these mills used recycled paper pulp as one component of their paper production

•De-inking carbonless copypaper resulted in PCBs in the waste streams of some mills from 1957-1971


Specific Study Objectives

Wildlife expected to have the greatest exposures and/or sensitivity to PCBs

•Mink•Bald eagles•Great horned owls•Passerine birds•Short-tailed shrews


Terrestrial Exposure Pathways

Aquatic Exposure Pathways


Receptor measurements

Mink

Fish/crayfish Small mammals

Benthic inverts Terrestrial inverts

Sediments Soils

Bald Eagle

Fish & Waterfowl

Benthic insects

Sediments

Turtles/mammalsMuskrats

Vegetation

Vegetation

Tissue Conc.

Abundance Demographics

Habitat suitability

Soils

Tissue Conc.

Foraging Range

Productivity


Receptor Measurements

Aquatic emergent insects

OwlsSwallows

Small mammals & Bluebirds

Terrestrial insects

Sediments Soils

Swallows/Muskrats

Terrestrial insects and Plants

Aquatic emergent insects/Aquatic Plants

Sediments Soils

Blue Birds

Productivity Nest Attentiveness Productivity Abundance

Tissue Conc. Tissue Conc

Biota Samples Collected• 196 sediment • 46 plant• 226 groups of aquatic insects• 138 groups of benthic invertebrates • 182 fish• 316 groups of terrestrial invertebrates • 146 small mammals• 12 pooled samples of crayfish• 8 turtles • 16 bald eagle nestling plasma• 1 bald eagle egg (addled)• 1 great horned owl adult• 16 great horned owl nestling plasma• 14 great horned owl eggs• 54 owl pellets• 14 adult mink • 153 passerine bird eggs/nestlings


Aquatic Emergent Insect Sampling


Benthic Invertebrate Sampling


Bird Box Studies


Small Mammal Sampling


Terrestrial Invertebrate Sampling


Dietary Composition


Non-destructive tissue sampling and productivity


Reduction of uncertainty by use of measured vs. predicted stressor concentrations

• In the absence of measured values for concentrations of PCBs in plants, values were predicted based on literature BCFs

• Variations in PCB mixtures and congeners resulted in a wide range of BCF values in literature.

• Measured values provide great reductions in uncertainties and associated conservative bias

PCB Concentrations in Plants

Uncertainties of Predicted vs. Measured Values

3.5

0.0000180

2

4

6

8

10

12

14

16

18

20

Predicted Measured

Plan

t PC

B C

once

ntra

tion

in m

g/kg

0.000018

0

0.000005

0.00001

0.000015

0.00002

0.000025

0.00003

0.000035

Measured

Plan

t PC

B C

once

ntra

tion

in m

g/kg


American Robin Hazard Quotients

Prey concentrationgeometric mean95% UCL geometric meanMaximum

(LOEL)0.0 - 0.10.0 - 0.3

0.6

Egg concentrationpredicted rangemeasured range

mg/kg, ww0.2 - 3.90.4 -3.8

(NOEL)0.1 - 0.30.1 - 0.8

1.7

(NOEL)

23

(NOEL)0.02 - 0.40.04 - 0.4

MSU-ATL HQsBLERA HQ


Red FoxHazard Quotients

Prey PCB Concentrationgeometric mean95% UCL geometric meanmaximum

(LOEL)0.0 - 0.020.0 - 0.04

0.06

(NOEL)0.0 - 0.10.0 - 0.2

0.7

(NOEL)

47

MSU-ATL HQsBLERA HQ


Mink Hazard Quotients

Prey concentrationgeometric mean95% UCL geometric meanmaximum

(LOEL)0.1 - 1.00.1 - 1.3

3.2

liver concentrationpredicted rangemeasured range (n=6)

mg/kg, ww0.6 - 10.60.049 - 6.0

(NOEL)0.1 - 1.60.1 - 2.0

4.9

(NOEL)0.25 - 4.30.03 - 2.4

(NOEL)

72

MSU-ATL HQsBLERA HQ


Great Horned Owl Hazard Quotients

Prey concentrationgeometric mean95% UCL geometric meanmaximum

(LOEL)0.0 - 0.10.0 - 0.2

0.3

Tissue concentrationpredicted rangemeasured range in plasma (n=5)measured range in eggs (n=5)

(NOEL)0.07 - 0.50.3 -0.430.65 -1.1

(NOEL)0.1 - 0.30.2 - 0.6

0.7

(NOEL)

5.1

MSU-ATL HQsBLERA HQ

Conclusions• Unrealistic predictions of harm may occur due to compounded conservative bias

• Risk measurements such as hazard quotients should be expressed as a ranges to help communicate uncertainties

• Risk assessments are an iterative exercises• The use of multiple lines of evidence should be used where significant uncertainties exist

Substantial Reduction of Uncertainty in a Baseline ERA after...

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