Mind the Science Gap: Oil and Water…and Dirt

by Shara Evans on February 24, 2012

This article is Cross Posted from Mind the Science Gap. Under the guidance of the Risk Science Center’s director Andrew Maynard, for ten weeks between January and April 2012, Ten Masters of Public Health students from the University of Michigan will post weekly articles, translating complex sciences into accessible science communication for a broad audience.

Joseph Martin is a second year Masters of Public Health student in Environmental Quality and Health. After graduation from this program, he will pursue a Ph.D. in soil science. His interests lie in soil science and chemistry, human health and how they interact, especially in regards to agricultural practice and productivity.

On July 26th, 2010, an Enbridge Energy Oil Pipeline leaked nearly 1,000,000 gallons of bituminous oil (that is, oil from tar sands) into a tributary of the Kalamazoo River. This was, in technical terms, very bad. The volatilizing organics caused many health problems, prompting evacuation of many residents, capping of wells and irrigation pumps, and a total ban on contact or fishing from the tributary and major portions of Kalamazoo River. (By contact, I mean any sport or activity which might potentially put you in contact with the water. All boating, swimming, synchronized swimming, or establishing underwater secret lairs is strictly forbidden.) Health suits are common against Enbridge, who has been tasked with cleaning and monitoring the affected water  bodies until they are safe again for human interaction.

Nearly two years later, there is still a total ban on surface contact or fishing from the affected waters. Farmers are losing income for lack of irrigation. Yet Enbridge claims that 766,000 gallons of the 843,000 spilled have been removed. What, as it has been asked, gives? Part of the reason is that yes, 77,000 gallons is a whole lot of petroleum to still be in a river ecosystem. But that doesn’t completely answer the question. Another important reason lies in the chemical properties of oil.

That last sentence was a bit of misdirection. Petroleum isn’t a chemical; it is many hydrocarbons plus a good deal of contaminants of varying types. Even if we ignore the contaminants (like sulfur), petroleum is a hugely complex mixture with many different chemicals to consider. A considerable portion of these chemicals violate one of the basic rules of “oil” – they sink. A portion of petrochemicals are denser than water and, though they will not dissolve, will sink to the bottom where it cannot be skimmed. In the lazy river attractions now ubiquitous at water parks, this would still not be a terrible problem. You could put a hose at the bottom and start pumping. It might take some time, but the way forward is clear.

But the big difference between the lazy river and a real river is the degree to which life proliferates, the usual sunburnt habitants of a lazy river notwithstanding. The Kalamazoo River, like most rivers in Michigan, has been full of living and dying creatures for the 11,000 or so years. The muck and sediment on the bottom, even when it looks just like sand, is full of organic matter, both living and not. And many of the petroleum sinkers will complex and bind with the organic and inorganic matter which makes up the river bed. (Similarly, if the sediment is churned up, or even in regular river water, floating petroleum chemicals can be bound to the sediment and contribute a significant or even majority portion of the total sediment contamination). All of this is combined with the fact that a lot of the oil itself, not just contaminated sediment, is sitting on the river bottom, (reportedly, some 200 acres of river bottom are still covered in this petroleum). All this also have to be cleaned up.

In truth, the fact that the sediment is contaminated isn’t of great human health concern – it’s really more the 200 acres covered in submerged oil. As long as you don’t spend a lot of time eating river dirt, swimming and boating should be fine. Where concerns could come up is with eating fish. Bottom-feeding fish, such as catfish, as well as many the tiny organisms which proliferate on the river bed, consume this bound petroleum and get it all up in them. All of this is great for making poison darts out of the entrée at a Kalamazoo fish fry. (Unfortunately, that’s not a big problem. A limited fish consumption advisory has existed for the Kalamazoo River since 1970’s, due to PCB contamination. In fact, in 1990, 35 miles of the Kalamazoo river was designated a Superfund site.)

In conclusion – this river’s messed up. But suffice to say, the effects from the contamination of this river will be felt for years and years, even after the submerged oil is dredged and the waterways re-opened for human use. (It will be a long time until the fish are okay to eat. The PCB’s themselves last for long time, regardless of the petroleum contamination). I think the best we can do now is remember that an ounce of prevention is worth a pound of cure.

Addendum – As you may have noticed, I’m kind of into dirt, and it’s what I’m trying to become good at writing about. All of my posts in this class/on this blog will be about the places where soil (even if underwater) and human health interact. But in writing about the sediment contamination from this spill, I glossed over what is likely the major cause of the health problems from this oil spill. Many of the really scary chemicals, like the infamous BTEX (benzene, toluene, ethylbenzene, and the xylenes) chemicals, will volatilize off into the air. It is these volatile chemicals which were responsible for the horrible smell from the spill. Chemicals like benzene and toluene are known to have serious health effects, (benzene is known to cause leukemia among many other health problems, and toluene can cause neurological damage.) I wanted to mention this to establish that the health concerns and claims of those affected by the spill against are serious and legitimate. Here is an excellent article on the spill and the health effects on those exposed from Al-Jizeera.

Image Credit: Mic Stoltz

Related posts:

  1. Mind the Science Gap: The Science Influencing the CDC Panel Recommendation for the HPV Vaccine for Boys
  2. Mind the Science Gap – Helping science students connect with a non-science audience
  3. Mind the Science Gap: Why Don’t More Kids Get Flu Shots?
  4. Mind the Scienge Gap: Beach Bums! Gastrointestinal Distress from Sand?

Leave a Comment

Previous post:

Next post: