The Alaska Fisheries Science Center Auke Bay Laboratory

The Impacts of Two-stroke Gasoline Engines on Fish

Dr. Jeep Rice

Recreational Boating

• 1 pleasure boat per person in U.S.

• Average use of jetski style craft is 77 hours

• Average for outboard motors is 35 hours

Two-stroke Engines

• Older engines are inefficient

• Can discharge 1/3 uncombusted

• Two-strokes discharge 2-200 million gallons per year

Alaska

Juneau

100 km

Canada

N

S

W E

Auke Lake, Alaska

• Small (46 ha) • 34 m deep • Cold water • Tannin stained • 1103m X 410m • 6 species of salmonids • Used: Apr-Oct by

motor craft

Boat Use on Auke Lake, 2003

0 10 20 30 40 50 60 70 80 90

Apr May Jun Jul Aug Sep Oct

No. of boats

Polycyclic Aromatic Hydrocarbon (PAH) research in Auke Lake Passive samplers (plastic strips)

Integrate over time (21-30 days) Very sensitive

- Seasonal inputs - Recreational use or urban run

off - Spatial trends

- Fingerprint sources

What are PAH and Why Focus on Them?

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 -Benzene

Acute Exposure Chronic Low LevelExposure

“Narcosis” death Leukemia

Why Passive Samplers?

3-4 ring hydrocarbons; pesticides; PCBs

Integrated sampling over time Hot spots; Low concentrations Seasonal Trends

Intermittent inputs

Passive vs Grab Samples

• Integrates over time • Easily deployed • No chemicals • Cover entire time • Sensitive (ppb) • Combines all sources • Standards don’t apply

One time onlySampling gear neededChemicalsCovers 1 time onlyCrude (ppm)Fingerprint sourceMatch State Standards

Bioavailability of Lingering Oil: PEMD Deployment and Retrieval

Polyethylene Membrane Device: PEMD

Seasonal Changes in PAH

0

200

400

600

800

1000

1200

1400

1600

Tot

al P

AH

(ng/

g)

May Jun Jul Aug Sep

PAH at two Depths

0

200

400

600

800

1000

1200

1400

1600

May Jun Jul Aug Sep

Tot

al P

AH

(ng/

g)

1 m 9 m

Interannual Variation in PAH

0

500

1000

1500

2000

2500

3000

3500

4000

Tot

al P

AH

(ng/

g

1999 2000 2001 2002

Boat Use and PAH

May Jul Sep

0

500

1000

1500

Total PAH (ng/g)

0 10 20 30 40 50 60 70 80 90

Apr May Jun Jul Aug Sep Oct

No. of boats

No of boats

PAH Profiles from Auke Lake L P D E

0

5

10

15

20

N0

N1

N2

N3

N4

BP

H

AC

Y

AC

E

F0

F1

F2

F3

D0

D1

D2

D3 P0

P1

P2

P3

P4

AN

T FL

A

PY

R

C1F

B

AA

C

0 C

1 C2

C3

C4

BbF

B

kF

BE

P

BA

P

PE

R

IDP

D

BZ

BzP

Perc

ent o

f tot

al P

AH

G r a b W a te r S a m p l e s

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

N0

N1

N2

N3

N4

BP

H

AC

Y

AC

E

F0

F1

F2

F3

D0

D1

D2

D3 P0

P1

P2

P3

P4

AN

T FL

A

PY

R

C1F

B

AA

C

0 C

1 C2

C3

C4

BbF

B

kF

BE

P

BA

P

PE

R

IDP

DB

Z B

zP

Perc

ent o

f tot

al P

AH

Passive Samples – 21 days

Grab Water Samples

(No BTEX)

(No 3-5 ring PAH)

Different Compositions

Different Sources Urban vs Atmospheric inputs Gasoline vs Fuel Oil Combustion vs Spill

Potential Sources of PAH in Auke Lake

• Recreational Use (PWC, motor boats, floatplanes)

• Highway Runoff • Residential Runoff • Wood Smoke

Conclusions

• Personal Watercraft are correlated with seasonal increases in PAH

• PAH are very toxic • Most PAH were in the top meter • Passive samplers successfully monitor

changes in PAH • Goal: Replace 2 stroke with 4 stroke

engines