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"The lowest quantity of oil and petroleum found was 16 parts per million in water from Katrina Key, the highest being 221 parts per million in a sample taken from a pool of water in Orange Beach where a child was playing."

This is no more valid than the "health effects" anecdotal data. Without knowing precisely where and how the samples were collected, any result is completely meaningless. There is lots of oil scattered around many places, without identifying the source (which "is" possible) you simply can't say that the source is from the spill

I'm an analytical chemist, this is my career specialty. So I "do" know whereof I speak.

"And something is seriously wrong when a water sample from Dauphin Island Marina exploded within seconds, breaking its glass container, probably the result of the presence of methane gas or a chemical oil dispersant in the water.

Again, more completely meaningless anecdotal data. There is nothing in either the dispersant or the oil that will have this kind of effect. ANY analytical chemist knows that when you add a solvent to ANY sample in a separatory funnel, that the sample will cause a buildup of pressure, as the changed solubility constants will cause outgassing, even of dissolved AIR, and that you have to be careful to vent that pressure. It could well be that the particular sep funnel was scratched and simply couldn't take the normal pressure change.

Here's a couple of down-thread comments from CHEMISTS:

Retired chemist. Done more sep funnel extractions than I want to think about. It could have been methane (I'm assuming you meant methane not methanol). It could have been a small crack in the glassware after it was washed. It may be that the extraction broke up the associated hydrocarbon-dispersant molecules and created a strong entropic effect that caused expansion or contraction. I don't think a broken sep funnel is newsworthy but then a lot of the stuff on cable news is not worthy."

"The solvents used in extractions, like methylene chloride mentioned above and hexane, are very volatile and depending on the analyst, how vigorously the sample is shaken, how long before it is vented, and the condition of the glassware, this kind of thing could just as easily happen with a distilled water blank. On the other hand, the sample could just as easily be 250 ppm gasoline and not break one in a hundred samples."

Even Prof Overton has emphasized we can’t see right now what is going on under the surface of the water and won’t know for several years the extent of the damage or the long-term effects of the use of this much dispersant over such a large area for such a long period of time.

And OSHA may not have found anything approaching the minimum levels of toxic components of dispersants but their level is probably based much more short term, like a work week. Recovery workers working offshore are around the toxic chemicals almost 24/7. Workers on boats, rigs drilling relief wells, and others miles off shore also have constant exposure.

For heaven’s sake even the company CTEH contracted by BP to monitor air levels as they related to recovery worker safety has released data that shows disturbing levels of toxic dispersants, the same chemical blamed for chronic health problems in Exxon Valdez recovery workers, in 20% of offshore recovery workers and 15% of near-shore workers.

At least admit the long-term effects could well be both serious and potentially invisible to the public...