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
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
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%
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
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.
During the last decade, more than one billion gallons of oil spilled worldwide.
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) – perwww.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 . 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 . 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 .
As an oil used in a crankcase, motor oil breaks down to
give a wide variety of oxygenated and aromatic
hydrocarbons . 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 .
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 . PAHs,
heavy metals, additives and antioxidants, trace levels of
chlorinated solvents, and PCBs have been detected in used
engine oil . As mentioned above, naphthalene,
benzo(a)pyrene, fluorene, and phenanthrene are common PAH
components of used motor oil .
Hope you can help...
[edit on 18-5-2010 by IgnoranceIsntBlisss]