media.
Before discussing the level of reporting, let's first familiarize ourselves with the chemistry here. "C8" is a trade name for perfluorooctananoic acid or PFOA. A brand name for this compound with which many people more familiar then they would be with "C8" or PFOA would be "Scotch Guard," a chemical product once manufactured by the 3M corporation and widely used in millions of homes and cars to create a protective layer on upholstery and carpet so that if one spilled coffee on them, they could wipe the coffee off without staining the fabric. The product worked very well, as I know, because I had some in my home for many years.
PFOA or "Scotch Guard" or "C8" belongs to a general class of compounds known as fluorocarbons. Most refrigerants are fluorocarbons, HFC's though most are not perfluorocarbons. The difference between fluorocarbons and perfluorocarbons is that in the latter case, all of the hydrogens in the original hydrocarbons have been replaced by fluorines.
One property of perfluorocarbons is their extreme stability. They don't normally participate in chemical reactions of any kind and thus there is no ordinary mechanism by which they are eliminated from the environment. For instance, the man-made compound perfluoromethane is used as a cleaning solvent in the manufacture of solar cells and computer chips. It has a GWP of 5,700, which means that it is 5700 times as potent molecule for molecule as is carbon dioxide in participating in "global warming." It also has an atmospheric half life of over 50,000 years, whereas the half lives of other global warming gases such as methane and carbon dioxide are on the order of a few decades.
Because perfluorcarbons do not participate in chemical reactions, and do not react in living systems, they are generally thought of as being "non-toxic." Teflon, which is a perfluoro polymer is an example. One could eat Teflon (and people frequently do, generally unintentionally) and not worry at all about toxicity, since teflon does not react with tissue. In fact, teflon parts are often used in medical devices for exactly that reason.
So what does all of this have to do with perfluorooctanoic acid and the article in question? First let's look at the article's early comment about how chemists at Dupont recognized that "C8" was in drinking water and marked it "personal and confidential." It sounds nefarious doesn't it? I'm sure that's what the author intended, to sound nefarious. Then it's darkly stated that the levels of "C8" rose from 1.2 ppb to 1.5 ppb! Further its stated how a pregnant woman exposed to "C8" transferred the compound to her fetus! Horrible! Horrible! Isn't it? "C8" moves in the placental barrier! Even worse!
What's missing folks?
Here's what's missing: A discussion of whether or not C8 is toxic in any way! Were it so, we ought to be hearing quite a bit about people who were severely injured by "Scotch Guard." Have you?
Here is an excerpt from a report on the toxicity of PFOA by the EPA:
"No treatment-related effects were reported at any dose level for any of the mating and fertility parameters assessed, including numbers of days to inseminate, numbers of rats that mated, fertility index, numbers of rats with confirmed mating dates during the first and second week of cohabitation, and numbers of pregnant rats per rats in cohabitation. At necropsy, none of the sperm parameters evaluated (sperm number, motility, or morphology) were affected by treatment at any dose level.
At necropsy, statistically significant reductions in terminal body weights were seen at 3, 10, and 30 mg/kg/day. Absolute weights of the left and right epididymides, left cauda epididymis, seminal vesicles (with and without fluid), prostate, pituitary, left and right adrenals, spleen, and thymus were also significantly reduced at 30 mg/kg/day. The absolute weight of the seminal vesicles without fluid was significantly reduced in the 10 mg/kg/day dose group. The absolute weight of the liver was significantly increased in all dose-groups. Kidney weights were significantly increased in the 1, 3, and 10 mg/kg/day dose groups, but significantly decreased in the 30 mg/kg/day group. All organ weight-to-terminal body weight and ratios were significantly increased in all treated groups. Organ weight-to-brain weight ratios were significantly reduced for some organs at the high dose group, and significantly increased for other organs among all treated groups."
http://www.epa.gov/opptintr/pfoa/pfoara.htmSounds scary doesn't it? Until at least you look at the doses being given the sickly rats, 30 mg/kg/day. Since an ordinary human being weighs between 50 kg and 100 kg, this corresponds to eating between 1.5 grams to 3.0 grams a day, every day, throughout an entire pregnancy. Put another way, in order to get this dose at the "horrible" level of 1.5 ppb (parts per billion) one would have to drink 75,000,000 grams of water, or 75,000 liters. I think the water would cause problems long before the PFOA.
The article goes on to list the fact that PFOA passes the placental membrane. So does that awful compound discussed here at DU, dihydrogen oxide.
Here is what 3M did with PFOA: They banned it, on the grounds that it was a persistent compound. You can no longer buy "Scotch Guard," except on the black market. This was erring on the side of caution. What scared them was 1) that the compound was extremely persistent, 2) Could be easily detected widely distributed in tissues and 3) that fact 2) could be used by a scientifically illiterate jury in a lawsuit to find a large judgment against 3M. The fact though that any toxicity associated with PFOA is subtle, if present at all.
Fluorocarbons can, under certain circumstances, disrupt hydrogen bonds (since fluorine, as a 2nd row electronegative element is hydrogen bonding) and hydrogen bonds are important to living systems. Therefore, even though they are chemically inert, it is possible to imagine that PFOA and other perfluorocarbons can indeed have some mildly toxic effects. (I note that it takes huge doses, apparently to kill a rat, though) However the concentrations required to achieve this effect is rather high, certainly much higher than the ppb that so upset the author of this newspaper scare story. (In a scientifically literate world, this article would be in the World Weekly News, and not the local newspaper.) Still I think the case is far from obvious that there was insidious intent here or that the case is far from as serious as the reporter implies. In fact, the reporter seems to be a fool. What is scary is that such fools are too often taken seriously.