Exxon Valdez:

Long Term EffectsFrom Residual Oil

(10 yrs, 4 research groups)

What is Different about the Exxon Valdez Oil Spill?

- $100 million into post spill research

- Fewer peopleeffects

- Isolatedenvironment

Three Species – Long Term Impacts:

1.) Pink Salmon 4 years

2.) Sea Otters ~10 years

3.) Harlequin Ducks ~10 years

What do these species have in common?Spawn

orForage

Intertidal Zone

Residual Oil Effects:

1.) IF Oil is still there

AND

2.) IF Oil is biologically available

AND

3.) IF there is toxicity paradigm shift

Is the Oil Still There?

2001 SurveyResults:

91 sites and9,000 pits

- 53 sites with oil- 38 sites without oil

100 Miles

Kodiak Is

Alaska P

eninsula

Kenai Pen.

Prince WilliamSound

Alaska

Gulf ofAlaska

N

Light Oil Residue

Moderate Oil Residue

Heavy Oil Residue

Subsurface Oil -

LOR MOR

HOR

Distribution of Oil 12 Years Later:

UpperIntertidal

BiologicalZone

(lower Intertidal) Oil Below Sampling Grid = YesHow far down = ?

Tidalzone (m)

+ 4.8+ 4.3+ 3.3+ 2.8+ 2.3+ 1.8

< 1m

Surface Oil(# of pits)

375658604029

5286991123117

Subsurface Oil(# of pits)

0

200

400

600

800

1000

TPAHng/g

dry wt

Clams

Ribbon

worm

sgu

nnel

Hermit c

rabDog

whe

lkSpin

dle w

helk

Musse

ls

4,400

Herring Bay1999

Is Oil Still Bioavailable?Prey Species

Is Oil Still Bioavailable?

1996 – 98 Sea Otters

1996 – 98 Sea Ducks

1. Elevated P450 in oiled areas

2. Poor population recovery in oiledareas (1989-99)

Predators

Paradigm Shift in Ecotoxicity

1970s:1-2 PAH rings

Mono Di PAH

WSF

1990s:3-5 PAH rings

Mono Di PAH

Weatheredoil

LC50 = 1 ppM

effects = 1-20 ppB

Different Toxic Mechanisms –from Different Toxic Compounds

Acute LC50Narcosis

Long Term“Reduced Fitness”

Mono Di PAH

WSF

Mono Di PAH

Weatheredoil

Different Toxic Mechanisms -

Chronic Low LevelExposure

“Narcosis” death Leukemia

Acute Exposure

Monoaromatics PAH

Different Toxic Mechanisms -

Chronic Low LevelExposure

“Narcosis” death Leukemia

Acute Exposure

BenzeneE.g.

Reduced Fitness Results In:

in Survival -

in Deformities

in Growth

in Predator avoidance

in Reproductive SuccessSupported by field and laboratory studies

Decreased Survival:-Pink Salmon

89

population #'s

EVOSspill

pre - spill

90 9192 93Field: ADFG

Elevated egg mortality in “oiled” stream

Field Research

1989 & 1995 OiledSalmon Streams

Shelter Bay, Evans Island

Grass

Grass

Grass

Grass GrassTransit Position

ModerateHeavy

Light

Observed Oil 1989

#1

Sample 1989 19951 ? 153 2 ? 328 3 29,800 24 U ? 14 M ? 64 L ? 11

Oil Concentration (ug/g)

ADFG Stream# 16613

L

M

T

U

#1

#2

#1 Sampling Stations

North

Scale10 m

#3

stream

Field Research

Dye Released inSalmon Stream

Field Research

Decreased Survival: Pink Salmon

% survivalto

eyed egg

Eggs Incubating in Oiled Gravel Reduces Survival to Eyeing

Lab Research

0.8 1.3 3.6 7.8 18 31 48Aqueous Concentration (ppB)

50

55

60

65

70

75

Exposure to Eggs (ppB PAH)

* *

*

-Extra fins

- Deformedmouth

- Metabolismproblems

Increased Deformities:Pink Salmon Alevin at Emergence

Exposure to Eggs (ppB PAH)

Lab Research

Delayed Growth:Effects to Salmon Fry

0 9 18 27 36 451

1.2

1.4

1.6

1.8

Aqueous Dose (ppB PAH)

% increaseIn weightPer day

Exposure to Eggs (ppB PAH)

Lab Research

Delayed Growth:Effects on Adult Salmon Returns

Control 5.2 19.40

0.5

1

1.5

**

% survivalof

returningadults

Exposure to Eggs (ppB PAH)

Lab Research

Conclusions:

Residual oil with 3-5 ring PAH

- can persist

- is toxic

- affects fitness

= Populations

100 Miles

Kodiak Is

Alaska P

eninsula

Kenai Pen.

Prince WilliamSound

Alaska

Gulf ofAlaska

1989 Exxon ValdezOil Spill

Exxon Scientists Disagree

89

population #'s

90 9192 93

10 5# Oiled Stream

12,000 1,200# Eggs per Stream

9 1# Years

Statistical PowerADFG Exxon

Oiled Mussel Bed 1999

Stratified Random Sampling Grid

100 m12.5m

A B C D E F G H+4.6m

+1.8m

0.51.0

1.5

2.0

2.5

3.0

1/2 meterdrops

96 randomly selected

pit locations

Total # random pits = 6,775