pollution

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spot
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pollution

Post by spot »

I can understand why oil spills at sea are undesireable from an environmental viewpoint, but why is http://news.bbc.co.uk/2/hi/americas/4795866.stm (Alaska hit by 'massive' oil spill), being as it is on land, distressing?
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Rapunzel
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pollution

Post by Rapunzel »

spot wrote: I can understand why oil spills at sea are undesireable from an environmental viewpoint, but why is http://news.bbc.co.uk/2/hi/americas/4795866.stm (Alaska hit by 'massive' oil spill), being as it is on land, distressing?


The oil sinks down through the ground into the water table. As underground water trickles downhill it joins up with other rivulets of water until it comes above ground as a stream. Pollution in the water table will infect the rivulets and stream and be carried downhill, until it eventually reaches the sea.

The (polluted) water will be used by people living in the area. It also affects the food chain. The pollution will decimate the local populations of herring, pink salmon and seals. Oil pollution on land will also affect any animals that might live or feed there.

I'm not sure what the land is like where the spill occurred. If it is tundra then it will affect plant growth for a decade or two, if its ice then the watershed will be infected and sealife which is still recovering from the Exxon Valdiz disaster will be affected again!

Cleanup operations are of no real help either. Oil is a biodegradable product which will eventually biodegrade within the sea water. However, in an effort to be "seen" to be dealing with the problem, the companies involved bring in people to pour chemicals onto the spill and to wash the birds with soapy water. The chemicals are NOT biodegradable and cause more longterm damage than the oil would if left untreated. The seabirds are covered in a natural lubricant which oils their feathers and allows them to sit on or dive into the water without soaking it up like a sponge. It also aids flight. When people wash the oil off the birds, they also wash off their protective lubricant. The birds can no longer dive into the sea for fish....and so they starve to death! More birds are lost because of this than would be lost if left uncleaned!

Hope that helps Spot.
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spot
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pollution

Post by spot »

I'm not convinced about the argument that even volatile components of the spill will spread. Here's a quote from the U.S. Geological Survey at http://water.usgs.gov/wid/html/GW.html#HDR10

USGS studies of a crude-oil spill from a broken pipeline in Bemidji, Minnesota, have indicated that large concentrations of petroleum-type hydrocarbons can be attenuated or removed from ground water through biodegradation. The size of the plume containing hydrocarbons at the top of the local water table has changed little during the 9 years of the study (1984-93). The chemistry of the plume components has been changing with time; however, biodegradation of the hydrocarbons has kept them within 450 feet downgradient from the oil source. Another factor that helped contain the plume is the presence of silt layers of low hydraulic conductivity near the oil at the top of the aquifer. This long-term study provides perhaps the best-documented case that natural attenuation is an effective treatment approach at some sites provided careful attention is paid to the hydrogeologic setting and the chemistry of the contaminants.


If oilspill constituents in a warm climate like Minnesota stay within 450 feet of the spill, then you'd think the North Alaskan land environment would lock it up even more tightly. I don't see any of that reaching any food chain, animal or human, and certainly not seawater.

I agree entirely with your criticism of short-term cleanup benefits at sea. I don't understand why any damage can be expected from the spill under discussion, other than to any microorganisms in immediate contact with or under the spillage itself. Carting it away would involve traffic to the area which would damage more of the environment than has already been affected. Dispersion would be appallingly destructive.
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