A Small Dose of Oil Dispersants

orThe Dark Side of Dispersants

or Oil Dispersants: Our Right to

KnowSteven G. Gilbert, PhD, DABT

INND/Toxipediawww.toxipedia.orgsgilbert@innd.org

INNDInstitute of Neurotoxicology 

& Neurological DisordersToxipedia - www.toxipedia.orgPutting scientific

information in the context of history, society, and

culture. http://www.toxipedia.org/display/toxipedia/Oil+Dispersant

What do these have in common?

Oil DispersantsPesticides

Flame Retardants

Oil Spills are US Gulf - BP

Kalamazoo RiverChina - NigeriaExxon Valdez

and .....

What is Crude Oil?

• mixture of hydrocarbons• lighter hydrocarbons methane, ethane, propane

and butane occur as gases• heavier ones from pentane and up are in the form

of liquids or solids• various aromatic hydrocarbons while the other

organic compounds contain nitrogen, oxygen and sulfur, and trace amounts of metals such as iron, nickel, copper, mercury, and vanadium

Oil Dispersants

Soap the Basics•Sodium or potassium salts of fatty acids •Made from common oils or fats with a strong

alkaline solution lye•Soap molecules • hydrophilic end, which dissolves in water• hydrophobic end, dissolves nonpolar

grease molecules

Soap / detergents

Soap a bit of History• First production of soap-like materials 2800 BC in Ancient

Babylon• Babylonian clay tablet from 2200 BC - formula for soap

consisting of water, alkali and cassia oil • Sapo, Latin for soap, first appears in Pliny the Elder's Historia

Naturalis, 80 AD discusses the manufacture of soap from tallow and ashes • 15th century - professional manufacture of soap Provence,

France• 16th century, more refined soap - using vegetable oils (such as

olive oil) instead of animal fats. • 1800s start of high-quality, transparent soap in London

Oil landfall in Gulf

Released4.9 million barrels (780×103 m3), or 205.8 million gallons of crude oil.

1,100,000 US gallons chemical dispersants were sprayed at the wellhead five thousand feet under the sea

Methods of Oil CleanUpSkim it offSoak it upBurn it offBreak it down

Turbulence and Oil dispersants (nature) (synthetic) ….. then oil degrading bacteria

What are oil dispersants?Common tool to remove

oil slicks from the water surface and increase the oil's rate of biodegradation.

By removing large slicks, oil dispersants are intended to reduce harmful oil exposures to birds, fish, and other wildlife.

Prevent oil from contaminating coast lines, estuaries, and beaches

Separates an oil slick into small droplets of oil

Water turbulence breaks up droplets more and disperses them in water column

Oil droplets consumed by naturally occurring bacteria or carried out into the open ocean

How do oil dispersants work?

How do oil dispersants work?Nalco - how they work

What’s in oil dispersants?COREXIT 9500

Distillates, petroleum, hyrdrotreated light

Propylene GlycolOrganic sulfonic acid

salt

COREXIT 9527• 2-Butoxyethanol• Propylene Glycol•Organic sulfonic acid

salt

Other Ingredients:• Butanedioic acid, 2-sulfo-, 1,4-bis(2-ethylhexyl) ester, sodium salt (1:1)

• Sorbitan, mono-(9Z)-9-octadecenoate• Sorbitan, mono-(9Z)-9-octadecenoate, poly(oxy-1,2-ethanediyl) derivs.• Sorbitan, tri-(9Z)-9-octadecenoate, poly(oxy-1,2-ethanediyl) derivs 2

• Propanol, 1-(2-butoxy-1-methylethoxy)

2-Butoxyethanol

Gulf workers reported irritation of the nose and eyes, headache, a metallic taste in the mouth, and vomiting

"should be handled as a CARCINOGEN--WITH EXTREME CAUTION“~NJ Dept Health

Prolonged or repeated exposures can cause damage to the liver, kidneys, lymph system, blood and blood-forming organs

Propylene Glycol

Clear, syrupy liquid that lacks almost any odor or taste.

"generally recognized as safe" for use in foodbut studies on the effects of different types of

exposures to humans and the environment do not exist or need to be further examined

skin irritant, repeated exposure to may cause sensitization, or allergy

Sulfonic acid salt

sulfonate is a salt or ester of a sulfonic acid. It contains the functional group R-SO2O-

sulfonic acids tend to be strong acids

Protecting or Threatening the Environment?

Oil dispersants increase exposure and uptake of hydrocarbons by fishCardiac problems, fluid balance issues, and

spine and skull deformation of fish embryosEarly life stage of aquatic organisms highly

sensitive fish, crustaceans, and mollusks Exposure Damage to

Species

Relationship between Temperature and Toxicity

Water temperature Toxicity to aquatic life

85-90 degrees surface temperature of Gulf

Negative effects on shrimp and scallops reversible at low concentrations, but the higher the concentration, the more likely that the effects will be irreversible

An Ecological Experiment“More than 1m barrels of chemicals have been deployed so far. This is common practice for oil spills on the surface; using them in bulk at depth, as in the Gulf, is an ecological experiment.”-The Economist- July 15, 2010

Safer/more effective oil dispersant products

available?12 of 18 EPA approved oil dispersants are

more effective at dispersing Southern Louisiana Crude Oil than the Corexit products used in Deep Water Horizon

14 of the 18 products are less toxic to a common species of fish (which one?) than the Corexit products currently in use

-Source: EPA

Problems with this experiment

Dr. Paul Anastas EPA “Toxicity tests not conducted at the same pressures and temperatures where much of the dispersant was applied – 5,000 feet beneath the surface at the wellhead. That leaves uncertainties about how the dispersant might affect the ecosystem at that depth.”

Precautionary Principle“When an activity raises threats of harm to human health or the environment, precautionary measures should be take even if some cause and effect relationships are not fully established scientifically.”Wingspread Conference, 1998.

Precautionary Principle• Setting goals (Health indicators)• Taking preventive action in the face of uncertainty• Shifting the burden of responsibility to the

proponents of an activity (Who benefits?)• Exploring a wide range of alternatives to possibly

harmful actions (Is it necessary?)• Increasing public participation in decision making

(transparency of information & environmental justice)

References✦ COMPARATIVE TOXICITY OF TWO OIL DISPERSANTS, SUPERDISPERSANT-25 AND

COREXIT 9527, TO A RANGE OF COASTAL SPECIES Alan Scarlett, Tamara S. Galloway et al.... Environmental Toxicology and Chemistry, Vol. 24, No. 5, pp. 1219–1227, 2005

✦ "CDC - Oil Spill Response - Dispersant Information for Health Professionals." Centers for Disease Control and Prevention. 19 May 2010. Web. 03 June 2010. <http://emergency.cdc.gov/gulfoilspill2010/dispersants_hcp_info.asp>.

✦ US EPA EPA Response to BP Spill in the Gulf of Mexico http://www.epa.gov/bpspill/

✦ Toxipedia - Oil Dispersants - http://www.toxipedia.org/display/toxipedia/Oil+Dispersant

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