Petroleum hydrocarbons in the coastal environment

Chris ReddyDept. of Marine Chemistry and

GeochemistryWoods Hole Oceanographic Institution, Woods Hole, MA

Petroleum hydrocarbons

• Petroleum is the biologic and geologic product of the “cooking and squeezing” of organic matter.

• It is composed of many compounds that can have different chemical, physical, and biological properties.

• Easiest to class as either refined or crude.

Wide-cutgas oils

Residual oils

Boi

ling

rang

e °F

Residuum

Boiling range °C

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1000

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Straight-rungasoline Middle distillates

Gasolinefractions

Homeheatingoil

Lightgas oil

Diesel

Heavygas oil

Heavylubes

Lightlubes

Kerosine

Jetfuel

max m

in

normalalkanes

branchedalkanes

cycloalkanes

nitrogen,sulfur, andoxygen

Gasoline Kerosene Dieselfuel

Heavy gas oil

Lubricatingoil

Residuum

Boiling point °C

020 40 60 80 100

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s

napthenoaromatics

aromatics

Percentageof moleculartypes

Oil in the coastal zone• Urban runofflarge input term “leaky faucet”,

mainly used crankcase oil from cars and trucks, relatively low acute toxicity, impacts urban areas.

• Oil spillssmaller input, but is a dramatic event that may be from a wide range of products, toxicity can vary, pristine areas are vulnerable.

• Natural oil seepslarge input for long times scales, crude oil with varying toxicity.

Why study the fate of oil?

• Excellent opportunity to observe how ecosystems react to anthropogenic perturbations.

• Use knowledge for “engineered” clean-ups.

• Societal issues (human and animal health)

• Oil Pollution Act of 1990

FloridaWild HarborSeptember 16, 1969Spilled 700,000 L of diesel fuel

Bouchard 65Winsor Cove October 9, 197441,000 to 140,000 L of diesel fuel

Historical Spills

Florida spill: Background

• On September 16, 1969, the barge Florida ran aground on rocks near West Falmouth, MA.

• Over ~650,000 liters of diesel fuel spilled into the water column.

• Storm winds from the southwest drove the oil into Wild Harbor.

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Concentration of total petroleum hydrocarbons (TPHs)(mg g-1 dry weight)

0 108642D

epth

(cm

)

Wild HarborAugust 2000

Florida spill (1969)

Atlantic marsh fiddler crab Uca pugnax

Burrowing depthMade plaster casts of burrows in areas of Wild Harbor and Great Sippewissett to compare burrow depths of oiled and non-oiled areas.

Peacock et al. 2005

RESULTS: Burrowing depth

Oil Non-Oil

Wild Harbor Wild Harbor Great Sippewissett

Mean depth (cm) ± s.e.

6.4 ± 0.6 16.2 ± 0.6 13.7 ± 3.2

Significant difference between oil and non-oil areas in Wild Harbor (t-test, p < 0.001)

Burrow casts

Wild Harbor (oiled) Great Sippewissett

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Concentration of total petroleum hydrocarbons (TPHs)(mg g-1 dry weight)

0 108642D

epth

(cm

)

Wild HarborAugust 2000

Florida spill (1969)

Santa Barbara Oil Seeps

• Releases >20,000 liters of petroleum daily.

• Seepage has been occurring for thousands of years.

• Sheens and tar balls along the Santa Barbara coastline are constant reminders of this natural process.

• Excellent opportunity to study the fate of petroleum in the marine environment.

• My group started work at this site a few months ago.

Seep stringer

Tarballs

Holly Platform product

Santa Barbara seep stringer

Santa Barbara beach tar

Santa Barbara beach tar

Summary

• Oil can have different properties and behave differently in the environment.

• Thanks to Helen White, Bob Nelson, Greg Slater, Jennifer Culbertson, Ivan Valiela, and Emily Peacock