Toxicitiy of crude oil, by percentage?

In attempting to understand what degree of harm is being caused, by whatever volume of oil being leaked, can anyone explain in detail the varying degrees of toxicity of crude oil?

Until a couple days ago I hadn't realized that about 49% of spilled oil evaporates into thin air. But what about the rest that dissolves?

Then I saw a guy claim that since a gallon of used motor oil can contaminate a million gallons of water, then therefore based on his guess of the leaked oil something like 61 TRILLION gallons of Gulf water is already contaminated.

There is obvious flaws in this logic, but it got me thinking, how much IS or CAN BE potentially contaminated to unsafe levels. Of course the water cycles out of the Gulf, so nothing is static here, but the potential does seem important in assessing the destruction of this or any other oil spill for that matter.

The problem is, despite a couple hours of research, no webpages jumped out at me that break down this reality.

Now what I do know is that about 50% of the crude evaporates, meaning once it does then its harmful effects are essentially gone. This leaves about 50% of the crude still in the water / whatever. But where do we go from here? Also helpful would be how fast does the other 50% evaporate?

What I also know is that about 6% of crude is tar, which isn't yummy stuff, but it tends to stay stuck together, unlike distilled motor oil with all of its additives and then new chemicals in it that occur during its intended use. Tar will stick to things, and its nasty, but it doesn't contaminate in the ways the rest of crudes more liquid toxic components do, as tar doesn't quite dissolve.

So this leaves us with about 45% of the crude, which is (perhaps) liquid enough to contaminate water in terms of alcohol-water, opposed to tarblob-water.

Can anyone help us understand the toxicity of this remaining 45% of crude?

I had a hard time finding data explaining the different components of crude beyond these foggy percentages:

Composition by weight Hydrocarbon Average Range
Paraffins 30% 15 to 60%
Naphthenes 49% 30 to 60%
Aromatics 15% 3 to 30%
Asphaltics 6% remainder
en.wikipedia.org...
Composition by weight Element Percent range
Carbon 83 to 87%
Hydrogen 10 to 14%
Nitrogen 0.1 to 2%
Oxygen 0.1 to 1.5%
Sulfur 0.5 to 6%
Metals



Here's some random data that I did come across that is relevant:

EXPLANATION: Backyard mechanics dump more used oil into Michigan's environment each year than the Exxon Valdez spilled into Alaska's Prince William Sound
...
EXPLANATION: Oil spills account for only about five percent of the oil entering the oceans.
The Coast Guard estimates that for United States waters sewage treatment plants discharge twice as much oil each year as tanker spills.
seawifs.gsfc.nasa.gov...
During the last decade, more than one billion gallons of oil spilled worldwide.
www.marinergroup.com...
Land runoff and recreational boating account for nearly 3⁄4 of the 5,000,000
gallons of petroleum released into the oceans annually
National Academy of Sciences 5/23/2203) – per

www.4.nationalacademies.org)

Here's what makes used motor oil different than crude oil:

Like several individual PAHs, waste crankcase oil has
been shown to be mutagenic and teratogenic [75]. The
results are mixed, but some immunological, reproductive,
fetotoxic, and genotoxic effects have been associated

The concentration of various PAHs is much higher in used
oil than in (fresh) lubricating oil [519]. For example,
Grimmer et al. reported concentrations of dibenz(a,c)-
anthracene, 4-methylpyrene, fluoranthene,
benz(a)anthracene, benzo(e)pyrene, benzo(g,h,i)perylene,
and benzo(a)pyrene, respectively, 36, 49, 253, 720,
1,112, 4,770, and 7,226 times higher in used compared
to fresh oil [519].

As an oil used in a crankcase, motor oil breaks down to
give a wide variety of oxygenated and aromatic
hydrocarbons [497]. Other organic compounds found in
waste oil include toluene, benzene, xylenes, and
ethylbenzene. Also present are organic and inorganic
compounds of chlorine, sulphur, phosphorus, bromine,
nitrogen, and metals such as zinc, magnesium, barium, and
lead resulting from oil additives and contamination
during use or disposal [752].

Used engine oil is a contaminant of concern, with large
volumes entering aquatic ecosystems through water runoff.
The major source of petroleum contamination in urbanized
estuaries comes from waste crankcase oil [762]. PAHs,
heavy metals, additives and antioxidants, trace levels of
chlorinated solvents, and PCBs have been detected in used
engine oil [519]. As mentioned above, naphthalene,
benzo(a)pyrene, fluorene, and phenanthrene are common PAH
components of used motor oil [75].
www.nature.nps.gov/hazardssafety/toxic/oilused.pdf

Hope you can help...

[edit on 18-5-2010 by IgnoranceIsntBlisss]

Maybe a consequence of oil industry and fed oversight incompetence is to insist on Freedom of Information laws to get quick factual information in disasters and abuse.
That helps us...

Umm…… It will get ate. By the little buggies in the sea, and on the land. I mean, the real little buggies, as in, microbes, and bacteria. There is a lot of organisms that consume, and thrive off of oil compounds.

www.examiner.com...

www.forces.gc.ca...

Even the tar balls will slowly disappear after a while if left out in the open; they will be consumed by the organisms in the environment. As long as there is oxygen in the environment for the little bugs to use to consume the oil, then they will do so. That is why they are concerned about depleting oxygen levels in the ocean close to the blowout. That is because of all the little bugs sucking up the oxygen as they feed off the oil and multiply. They multiply so much that there isn’t enough oxygen for all of them to breath.

Like, if you spill some oil on the ground, if it stays close to the surface where there is air, it will quickly disappear. The only time it will hang around for a while is if it settles deep in the ground where there is little, to no oxygen. That will mean that the little bugs that eat it, can’t breath. In places where they have oil contamination, they will some times drive pipes into the ground, and pump air into them, to aerate the ground deep below. That allows the little bugs to survive and quickly break down the oil in the ground.

Oil is just hydrocarbons. Very close to the make up of simple sugars. Most sugars are just partially oxygenated hydrocarbons. A lot of organisms can feed off of both just as easily.

Heck, if there wasn’t stuff constantly consuming crude as it comes to the surface, we would be up to our ears in oil. Do you think all that oil just stays down there? Think about it. The plates crack, and holes open up. There is thousands of natural oil seeps across the globe. The total amount of oil continuously coming out of all of them would dwarf the BP blowout by at least an order of magnitude. The only difference with all of them is they are spread out. All the little life in the ocean makes quick work of the stuff as it comes up.

The only thing that I have pondered is. We know there is some pretty big oil deposits in some places. We know that once in a while, a new fault opens up in a random location. The logical conclusion is… sooner or later, a fault will rip through a very big oil deposit, and the whole thing will come up at once. I mean a BIG deposit, not some little pip squeak like the couple million barrel deposit that is currently hemorrhaging. I mean multi billion barrel. It is not a question of if, but just when. What would be the fallout from such an incident?.

And it is probably safe to say that is has happened in the past, too. What would happen if a 5 billion barrels of oil came to the surface of the ocean in just a couple days? An oil volcano! It wouldn’t be a single pipe to fight, It would bee a thousand mile long fisher!




[edit on 18-5-2010 by Mr Tranny]

[edit on 18-5-2010 by Mr Tranny]

reply to post by Mr Tranny


Something went wrong with your links.

That still doesn't speak to the actual toxicity of crude. But what about any data that gives some concept of how long it takes the bacteria to eat the oil?

The links should be fixed.

The time depends on the oxygen supply, and number of organisms you start out with. I will see if I can find some links to some stuff I seen several years ago.

The first is about bioremediation in general.
The next one is about using it in the ocean and such.
Then, a few more general articles.
The last few on the list are more technical, in regards to ground contamination.

www.biotechinstitute.org...

conservancy.umn.edu...

www.clu-in.org...

conservancy.umn.edu...

ipec.utulsa.edu...

www.epa.gov...

pubs.nrc-cnrc.gc.ca...

www.cluin.org...

iahs.info...

They should give you an overall view.

Edit…….
Forgot to mention a paradigm shift that happened a while back.

Up until the late 90’s all the “scientist” though that the explanation for oil breaking down in the environment was strictly a result of chemical degradation.

Until a few test proved that it wasn’t by normal chemical means. Then the scientific world finally come to the crystal clear realization that it was the organic life feeding off of the oil that was causing it to disappear in the environment. Duh……

They forgot the basic idea that all organisms will try to adapt, to use any source of energy they can find. Oil has been around a long time before we have. Other organisms have be using oil for energy long before we discovered it. And, if you happen to spill any of it, there is a army of little buggers that is just waiting to get first dibs at the diner table.

After that realization, then they started coming up with ideas on how to boost that natural process.


[edit on 19-5-2010 by Mr Tranny]

UPDATES on the oil:

Light crude contains volatile organic compounds which evaporate. Thus, light crude oil will lose up to 10 to 15% of its volume immediately, and up to 25% of its volume within 24 hours. How much of its volume is lost depends on the surface-to-volume ratio of the bulk oil. Events that disperse the oil, such as a well blowout, can affect this. Thus, crude oil in a pool or tank will retain more of its volatile components than crude in an oil slick.[2]

When oil is spilled in the ocean, it initially spreads primarily on the surface of the water. How much it spreads depends on its relative density and composition. The oil slick formed may remain cohesive, or, if seas are rough, it may break up. Waves, water currents, and wind can force the oil slick to drift over large areas, impacting the open ocean, coastal areas, and marine and terrestrial habitats in the path of the drift.

Oil that contains volatile organic compounds partially evaporates, losing 20 to 40 percent of its mass and becoming denser and more viscous. A small percentage of oil may dissolve in the water. The oil residue also can spread almost invisibly in the water or combine with water to form a thick mousse-like substance. Part of the oil waste may sink with suspended particulate matter, and the remainder eventually congeals into sticky tar balls.

Over time, oil waste deteriorates (weathers) and disintegrates because of exposure to sunlight (photolysis) and biodegradation. The rate of biodegradation depends on the availability of nutrients, oxygen, and microorganisms, as well as temperature.
www.cdc.gov...

Still not having much luck on the tar etc content on 'light crude' or more importantly the specifics of this specific oil.

The only Wikipedia entry that has a percentage listing is the generic "Petroleum" page. The entries for Light Crude, etc don't have percentage listings. Are we to assume that the Petro page is listing the components of 'medium crude', or what.

In my view this is all critical info in damage assessment.

The crude oil that is spilling into the Gulf is called MC252, or Louisiana Sweet Crude. When it reaches the surface of the water, it spreads into a thin slick that is dull or dark brown in color. As wind and waves tear the slick into smaller patches, various processes begin to work on the oil, changing its appearance and physical characteristics.

Oil that reaches the shoreline might appear as mousse or tar balls. Oil mousse is a mixture of oil and water. It is brown, rust, or orange in color with a pudding-like consistency. Oil mousse can sometimes be confused with algae. Tar balls are small, dark-colored pieces of weathered oil that may stick to your feet when you walk on the beach. Tar balls also occur naturally and wash up regularly on Gulf Coast shorelines. pensacolabeachhistory.com...

When the Exxon Valdez struck Bligh Reef in Prince William Sound in Alaska 21 years ago, it spewed 10.8 million gallons of heavy crude oil onto pristine shores. Only 10 percent of the spilled oil was ever recovered. The April 20 explosion and fire that killed 11 aboard the Deepwater Horizon released a different grade of petroleum product, "Louisiana sweet crude."
...
"It's called sweet because it has a sulfur content of less than 1 percent," said John Curry, director of external affairs for BP. "It's thinner and it's a lot lighter than heavy crude." LINK

Well I finally found a document that lists the tar content of Sweet Louisiana Light, but it costs $ that I cant afford:
Determin ation of Asphaltenes in Petroleum Crude Oils by Fourier Transform Infrared Spectroscopy

This document doesn't list the tar %, but it is very useful:
www.deepwaterhorizonresponse.com...

The oil from the Deepwater Horizon/BP spill is known as Light Louisiana Crude, which does not contain hydrogen sulfide. The
components of Light Louisiana Crude which are of most concerns to public health, such as benzene, evaporate quickly once the oil
reaches the surface. As much as 40 percent of the oil spill volume may evaporate in the first 24 to 48 hours after being released.
www.deepwaterhorizonresponse.com...

MSDS (seems generic though)
MC252 Addendum (seems flawed)


[edit on 26-5-2010 by IgnoranceIsntBlisss]

The details of crude oil maybe good to add to the 3D simulation of the gulf, as it evolves:

Researchers race to produce 3D solution for BP oil spill: Weather & Economic Simulations

They'll need to know economic data of the affected areas. It may help with the solution for the clean-up or to return the situation to its previous carbon neutral state. May help prevent medical issues, too.