Talk:Perfluorooctanoic acid

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Neutrality Disputed[edit]

The article has an anti-PFOA bias. While it correctly notes that PFOA is very stable and long lived, it does not give any evidence that PFOA is toxic, or state any mechanisms of PFOA toxicity (the C<sub7F15 part is relativly inert, and there is no reason why the COOH group, by far the most reactive part, be toxic to humans, and there are no Known processes it inhibits like fluoroacetic acid, which inhibits the Krebs cycle) but then quotes various groups as stating that PFOA shold be banned. While these viewpoints should be represented, the arguments of PFOA supporters should also be given to meet the NPOV policy. Polonium 20:56, 31 January 2006 (UTC)

Ok, so why don't you give some detail, and integrate your argument in the article to present the whole picture. The given fact is, that DuPont had to pay quite some money to U.S. EPA (which is not just another public watchdog group, is it?), because serious facts

about the toxicity of PFOA had been suppressed. --Olaf g 16:16, 31 January 2006 (MET)

Everything in the article looks like facts from verifiable sources. Please provide some balance to the article. It looks like you have the information. I have not found anything from PFOA supporters to add. Be sure to cite your sources. -Thanks Nv8200p talk 16:45, 1 February 2006 (UTC)

Neutrality (again)[edit]

This is not to provoke conflict or question sources, but rather, a request to increase the total amount of content in the article. While everything is well sourced, I feel the overall neutrality of this article could be improved somewhat if the actual use of the compound were described a little better. For example:

  • more description of how it does what it does in the processes it is used for.
  • more description of why PFOA and not some other length side chain was selected.
  • comparison of PFOA method of producing PTFE coatings and other methods
  • comparison of environmental damage caused by PFOA to environmental damage prevented due to resources saved by greatly simplified cleanup (think about it: PTFE-coated dishes may help keep a LOT of cleaning supply waste out of the municipal wastewater stream!)

Adding this sort of information would definitely improve the feeling of neutrality of the article. Zaphraud (talk) 13:28, 15 June 2008 (UTC)

Chemistry and processing info needed[edit]

I was very impressed by this article, but it does lack chemistry. PFOA is an interesting carboxylic acid - somewhat related to trifluoroacetic - with a synthesis, properties, and a history that would be relatively neutral (so to speak!). Also, the article seems to imply that PFOA is a component of Teflon whereas my understanding is that it is a kind of surfactant that is required for the (aqueous) emulsion polymerization. I dont know enough of the underlying polymer chem to explain the actual role of the PFOA in the making of Teflon. --Smokefoot 02:19, 30 April 2006 (UTC)

Seems out of place[edit]

The paragraph:

Public watchdog groups are raising the alarm about PFOA. The Environmental Working Group says, in an online report titled "PFCs: A Family of Chemicals that Contaminate the Planet", that "PFCs seem destined to supplant DDT, PCBs, dioxin, and other chemicals as the most notorious, global chemical contaminants ever produced." As with most toxic chemicals, proving that PFOA is dangerous is very difficult and expensive. However it is up to the people who make these chemicals (which never before existed on earth) to prove they are safe before introduction so as to avoid another DDT mess. Moreover there are already serious concerns and a ban is being discussed.

seems out of place, especially the section after the quote describing what should be done about toxic chemicals. While the author is probably right about proving chemicals are safe before they are used, I don't think that information needs to be included in this particular article. I think the paragraph should either be removed entirely or reworded to address the specific hazards associated with PFOA, not environmental policy in general. Jayrandom (talk) 21:01, 27 June 2008 (UTC)

Having read through the recent history, I think I understand where the dispute is coming from. It is definitely not acceptable in its current form, which expresses a strong POV and is completely off topic for this particular article. Is there a way to say that people are concerned about these substances without the diatribe that seems to mostly be a response to a previous users edit? Jayrandom (talk) 21:09, 27 June 2008 (UTC)

Category:Suspected persistent organic pollutants[edit]

I thought contributors to this article might be interested in this CFD notice. Cgingold 04:53, 1 November 2007 (UTC)

This article is NOT a review for a toxicology journal - it's for an encyclopedia[edit]

With hundreds of thousands of publications appearing each year, it is easy to fill any wikipedia article with lots highly specialized references. Anyone can do that! This resource is not intended to be based on narrowly focused (and western-focused) content, but on broader sources, e.g. from books or possibly reviews. Journal references should be to seminal advances, they should not be numerous. In such a manner, the article becomes more accessible to readers because the focus is broad. IMHO.--Smokefoot (talk) 03:30, 27 August 2008 (UTC)

I don't see a real problem here. There is currently a lot of research ongoing on PFOA. If we always have to wait for reviews and books to be published, the information is delayed too much IMHO. --Leyo 08:09, 27 August 2008 (UTC)

Details important because of inaccurate media coverage[edit]

I added details that may be painful to the eye (LOD, detection rate, ng/mL, ppb, and % change etc.), however, these details are important because I keep seeing inaccurate media coverage. For example, in the LA Times, David Lazarus recently wrote this scientific garbage [1] when the truth is PFOA is not used to prevent food from sticking to paper packaging (it's an unintended contaminant), PFOA levels are declining in the U.S. population (EWG's statements mislead you to think they are increasing), PFOA was detected in 99.7% of Americans (not 98%), PFCs are noted for their thermal stability and do not easily break down (unless you are at temperatures above cooking range), PFOA may be having developmental health effects on Americans at current levels (by lowering birth weights & industry argues that possibility is not necessarily harmful to health), and PFOS is also decreasing in the blood of Americans (at a more rapid rate than PFOA), and the fluorinated chemicals (fluorpolymers or fluorotelomers) used on the paper are not used to keep food from sticking, but rather to stop oil from soaking into paper, because no one wants wet oily paper food wrappers as saturated evidence of all the fat they are ingesting. The other news article I saw suggested the LOD for a PFOA "test" was 10 ppb, so I think it is very important to demonstrate current LODs as they apply to relevant methods. I was even thinking of creating a section "Inaccurate Media Coverage of PFOA". Since it's an LA Times article it is supposed to be "good" so smaller media outlets have parroted the factually incorrect information. Very frustrating... and California is dealing with SB 1313 right now... Shootbamboo (talk) 05:28, 6 September 2008 (UTC)

Check  your facts better. 

3M made PFOS not PFOA. PFOS was the product 3M took off the market not PFOA. PFOS was used in Scotchguard. Dupont makes/uses PFOA. It is used (they say) in the production of Teflon products. But Telfon off-gases PFOA. Their main production facility is in WV and local wells in the area have high levels of PFOA. EPA fined them twice under TSCA 8e violations for not disclosing important health data about PFOA. Envirtox (talk) 01:57, 23 September 2008 (UTC)

Envirox your minor edit contains factually incorrect information. "Regarding PFOA, 3M had manufactured the compound primarily for commercial sale to other companies. As a result of its phaseout decision, 3M no longer manufactures or sells PFOA."[2] Was the "Check your facts better" directed towards something I wrote factually incorrect? -Shootbamboo (talk) 02:27, 24 September 2008 (UTC)


Issues of Neutrality[edit]

Cacycle, I am uncertain as to your specific issues. I am a newer editor and I am confused because you didn't put anything here, despite the link you inserted to Wikipedia:No_original_research#Primary.2C_secondary_and_tertiary_sources stating "Appropriate sourcing can be a complicated issue, and these are general rules. Deciding whether primary, secondary or tertiary sources are more suitable on any given occasion is a matter of common sense and good editorial judgment, and should be discussed on article talk pages." Please do. I understand that "While each fact mentioned in the article might be presented fairly, the very selection (and omission) of facts can make an article biased" Wikipedia:NPOV dispute. What facts should be incorporated, or which facts should be omitted, in your opinion?

As it relates to your NPOV dispute regarding "undue weight on persistence" I would like to point out that the persistence of PFOA is a big reason (together with the facts it binds to serum proteins & is toxic to animals) why we are talking about it. If it was metabolized or broken down, we'd forget about it, cause it wouldn't be there anymore. But unfortunately PFOA does persist, in people, water, animals, food, etc. But that doesn't mean PFOA is indestructible! (And it might even, at tiny rates, decompose in the environment, but I doubt it, because I think it took some 185 UV to really get things going). I have been meaning to cite the studies where researchers have found successful ways to degrade PFOA (because of water contamination issues). Canada has banned PFOA precursors because of perfluorinated chemical contamination issues in the Arctic. I haven't mentioned that yet either. I would love to beef up the toxicology (mechanisms) etc., epidemiological surveys of fluorochemical workers, and data on highly exposed populations, (all the the C8 science panel info), but I have been working my way down the page. Today I invited a expert on this subject to assist in the editing of that section, because I really think it looks piecemeal.

Perhaps you are also referring to previous neutrality issues? I have worked to address issues raised regarding neutrality. Am I supposed to talk to those editors to get their approval so they can not dispute the neutrality of the article? Thanks. -Shootbamboo (talk) 06:49, 13 October 2008 (UTC)

I will respond to the tags, which I support. The article is overly detailed. Little effort is dedicated to a nuanced overview vs enumerating individual highly detailed reports. The many references indicate a lack of perspective and the unwillingness to omit detailed report. Yes, I have heard the sanctimonious mantra before - each technical report is precious and notable. Yes, PFOA binds to proteins (few charged species do not). Yes, tox studies show effects (try to publish a tox. paper with a non-effect). Yes, PFOA is persistent (perhaps better persistent than reactive?). On a different level, you should explain yourself and your interests/agenda on your wiki-home page. You should, through broadened editing activities, contribute to other technical articles to demonstrate an ability to balance and integrate technical knowledge vs enumerating reports. Experience shows that long single-author reports often reflect an agenda beyond that of communicating a balanced overview.--Smokefoot (talk) 12:59, 13 October 2008 (UTC)
Smokefoot. We were in the middle of this conversation over a month ago, User talk:Shootbamboo. How many references/words should be allotted to the PFOA page, in your opinion? Can you give me examples of parts of the page you find "detailed" and other sections that are "nuanced"? I found the discussion at the top of my user page productive. It is very frustrating not getting any specifics about page edit suggestions. It seems the only way you get out of talking specifics is to accuse me of bias. My plan is to get PFOA looking good then establish other pages/sections on related chemicals/chemistries and then expand to other chemicals. It could have been PFOS first but I decided upon PFOA because it is more discussed in the media. Also there is the population around WV/Ohio that is undergoing surveying.[3] -Shootbamboo (talk) 23:51, 13 October 2008 (UTC)

The most important part under Wikipedia:No original research#Primary, secondary and tertiary_sources is this:

"Wikipedia articles should rely mainly on published reliable secondary sources and, to a lesser extent, on tertiary sources. All interpretive claims, analyses, or synthetic claims about primary sources must be referenced to a secondary source, rather than original analysis of the primary-source material by Wikipedia editors.
Primary sources that have been published by a reliable source may be used in Wikipedia, but only with care, because it is easy to misuse them. For that reason, anyone—without specialist knowledge—who reads the primary source should be able to verify that the Wikipedia passage agrees with the primary source. Any interpretation of primary source material requires a reliable secondary source for that interpretation."

I cannot remember having ever seen a chemistry or toxicology-related article on Wikipedia with that many references (currently 85!). A disproportionately large number of these references seem to be primary sources as opposed to secondary sources (i.e. review articles). Primary scientific results are always ambiguous and preliminary. If a scientific topic has not been scientifically reviewed by carefully and competently assessing all relevant findings and by putting them into context, then it should not be included in this article. We simply cannot and should not do this ourselves on Wikipedia, especially for controversial topics. Please take this as a very general remark, we certainly appreciate the hard work that you have put into this article and do not assume bad faith or intentional misrepresentations on your site. But Wikipedia is an encyclopedia and has its special rules and limitations. I guess most of us had to learn this at one point... Cacycle (talk) 01:12, 14 October 2008 (UTC)

Thank you for pointing out the focus on secondary sources. I understand the necessity. However, I do not agree with the idea that primary scientific results are always ambiguous and preliminary. Take the primary source for PFOA being found in the Anarctic, for example. PFOA was found there. That is neither ambiguous nor preliminary. It is fact, and it requires no interpretation. But, if you were just over-stating the potential pitfalls of primary sources, to make a point that I needed to hear, then I completely understand. Thanks. But, my impression is that, the more controversial a subject is, the more information is required to put things in context. What justification is there, Wikipedia policy wise, for a set # of references for a given article? -Shootbamboo (talk) 02:09, 15 October 2008 (UTC)
The detection section is a good example. Modern analytical procedures are becoming insanely sensitive and the ability to detect minuscule amounts of certain compounds just depends on how close you look and how much time and effort you invest. The mere occurrence of a substance is useless information unless the concentration is stated. Even then, without toxicological context and multidisciplinary background information it is not possible to draw any conclusion from this.
As for the number of sources, I am not aware of an upper limit of references in Wikipedia articles. I would not worry about adding too many sources :-) as long as they are appropriate and contribute to the quality of the article. I gues you have already visited Wikipedia:Citing sources. Cacycle (talk) 03:24, 15 October 2008 (UTC)
I disagree on calling the (mere) occurrence a useless information, especially for remote areas. The detection in the Arctic and Antartic regions provides an indication on the long-range transport potential of PFOA. However, it would not a bad idea to state concentration ranges in the section mentioned anyway. --Leyo 09:19, 15 October 2008 (UTC)

One general comment. I'm always a bit skeptical when feeding large concentrations of something to an animal and observing detrimental effects is labeled as a "health concern". For example, does the fact that feeding 300 ppm of PFOA to rats causes tumors really tells us anything about the effect of a few ppb in humans (a concentration hundreds of thousands of times smaller!)? Whether you believe that the effect scales linearly or not, there will always be some point at which the effect becomes undetectable (the real question is, what is this point?) My favorite analogy is this one: the fact that solid lead at high velocities can be deadly bears absolutely no correlation with the toxicity of 1 ppb of lead in drinking water. ;-) --Itub (talk) 13:58, 16 October 2008 (UTC)

This analogy reminds me on this cartoon. :-) --Leyo 19:12, 16 October 2008 (UTC)
@Itub/Leyo: Fair enough, but this, in fact, is how risk modern risk assessment works. The gold standard—human experimentation—is off limits for obvious reasons, so you've got to rely on animal experiments. (There's also epidemiology, but ideally you can identify a hazard earlyon and thus prevent levels of human exposure that would cause harm, thus obviating the need for—and even possibility of—doing epidemiology). So you're stuck with animals, and it's a lot easier, quicker, and cheaper to give high doses to a relatively small number of animals and then extrapolate to figure out the effects of low dose exposure—it's a lot more convenient to do that than it is to actually do low dose exposure studies. Cancer is good example. You can give 1 mg/kg/day of a chemical to 50 rats for 2 years (a rats's lifetime), and if it's a potent carcinogen you should be to see statistically significant increase in cancer vs controls. Let's say it causes 5 cancers. So you say 1 mg/kg/day increases lifetime cancer risk by 10%. Let's say typical environmental exposures to this chemical in the real world are only 1 μg/kg/day. What's the cancer risk? If you assume it scales linearly (a big but necessary assumption) then it's 10%÷1000 = 0.01%, which doesn't sound like much, but if 100 million people are being exposed at this level, that's 10,000 extra cancers. Now, let's say that instead of dosing the rats at 1 mg/kg/day, you instead used 1 μg/kg/day. How many of those 50 rats would get cancer? Less than one—you wouldn't even see an effect. In fact you'd need to use hundreds or thousands of rats to see a statistically significant effect, and that's not an experiment you can feasibly do. So my point is that extrapolating the results of high dose toxicology in rats to low doses in humans is necessary, since there's simply no other way to figure this stuff out. Yilloslime (t) 19:57, 16 October 2008 (UTC)
I agree it's the way it has to be done and I respect the people who do those studies. The problem is when a study is cited in a Wikipedia article in a way that gives the impression that the compound in question is certain to cause cancer. For example, this one says that PFOA acid induced tumors in rats, but it doesn't say anything about the probability. Did it induce it in every single rat, or in 10% of the rats? And then, while it does mention the concentration used, it does not make an explicit comparison with the concentrations found in the real world. Inattentive readers might fail to notice that in one case the unit used is ppm while in the other it is ppb and get the impression that they are certain to get cancer from using a Teflon pan, while in reality they are probably more likely to die in a traffic accident! If there is a good reference explicitly making an estimate like the one you made above of how many people might actually be affected, it would be helpful. Because otherwise, just presenting a raw selection of primary-sourced facts in the "right" order can induce someone to think that this is the most toxic substance since Zyklon B (or that it is the best thing since sliced bread). Which is of course what advocates on both sides of any environmental or health issue do all the time. :) --Itub (talk) 09:24, 17 October 2008 (UTC)
I am unhappy with the look of the health concerns section also, I plan to be bold with it and to incorporate ideas. Please, feel free to be bold too! Thanks for the discussion. -Shootbamboo (talk) 12:30, 18 October 2008 (UTC)

Unused links[edit]

  • [4] Chemical in Teflon, other goods is turning up in disturbing places, Seattle Times Oct 1, 2004
  • [5] DuPont, Now in the Frying Pan, NY Times Aug 8, 2004
  • Farkas, Brian (Associated Press). "Plant tests thousands for exposure to Teflon chemical". Austin American-Statesman (November 18, 2005), p A27.
  • "DuPont reaches $16.5M deal with EPA". CNNMoney. Retrieved Dec. 15, 2005.
  • Michael Janofsky, "E.P.A. seeks to phase out a toxic chemical," New York Times, Jan 26, 2006
  • Martin, J.W.; Smithwick, M.M.; Braune, B.M.; Hoekstra, P.F.; Muir, D.C.G.; Mabury, S.A. "Identification of Long-Chain Perfluorinated Acids in Biota from the Canadian Arctic." Environmental Science and Technology 2004, 38 (2), pp. 373-380.
  • Ellis, D.A.; Mabury, S.A.; Martin, J.W.; Muir, D.C.G. "Thermolysis of fluoropolymers as a potential source of halogenated organic acids in the environment." Nature 2001, 412 (6844), pp. 321-324.

If anyone can find a use for these links to reincorporate them please feel free. Thanks. -Shootbamboo (talk) 12:30, 18 October 2008 (UTC)

History[edit]

I removed this from the section Health Concerns "DuPont, one of the largest U.S. users of PFOA, then built its own plant in Fayetteville, North Carolina to manufacture PFOA." because it is not sourced, if someone can source it please do and incorporate it into the History section. -Shootbamboo (talk) 18:06, 18 October 2008 (UTC)

Done. Data has been reincorporated and sourced. -Shootbamboo (talk) 01:57, 9 February 2009 (UTC)

353 journal and review papers are listed in Chem Abs for PFOA - for 2006, 2007, 2008 alone[edit]

An update on my concern about this article being swamped with literature and the threat of this approach to Wikipedia-Chem. My quick check shows that ca. 960 papers (Engl, Fr, German language only) have been published on PFOA, including hundreds in recent years. So why does this article merit nearly 10% of the available literature? Nitrobenzene, nasty and large scale, gives 12,000 hits. Its well-regarded wiki article cites 5 references. It it were to grow proportionately, nitrobenzene would have 1200 references - we seek that??--Smokefoot (talk) 19:16, 18 October 2008 (UTC)

sorry I just don't get the logic. try this. go to google. search news for nitrobenzene. then search news for PFOA. compare. by the way, why did you take the PFOA precursors fluorotelomer alcohols off of the perfluorocarbon page? [6] (under the Perfluorooctanoic acid section of your talk page?) -Shootbamboo (talk) 05:03, 19 October 2008 (UTC)
Smokefoot I would like to draw your attention to the importance of fluorotelomer alcohols and their relevance for PFOA, in an article I just found. [7] and additionally here [8] I am frightened by the possibility you are trying to hide the sources of environmental chemicals from the Wikipedia community. Can you please explain yourself? -Shootbamboo (talk) 16:14, 19 October 2008 (UTC)
Here is my re-explanation for my complaints about what I call your "lit-swamping": (1) I think that the readability of an article in Wikipedia declines when articles contain large numbers of footnotes. No doubt PFOA is more topical than nitrobenzene or even benzene and lots of other material. But I am not sure that topical-ness (trendiness?) is the prime criterion for determining the number of references or ranking importance. (2) I think that by collecting numerous references, you are synthesizing a construct with a biased perspective. Citing large amounts of literature is a device often used by authors/editors inexpert in technical matters but passionate about topic. The overall argument that we are engaged in centers on one's perspective on Wikipedia - some see it as a Whole Earth Catalogue equivalent and some (me, and possibly not many others) see it as a more sober, slightly detached (NPOV) description of the world optimized for readability.--Smokefoot (talk) 19:54, 19 October 2008 (UTC)
inexpert in technical matters? i am new to this so i could be all wrong...but you have led me to cite this [9] where i had to correct you on the simple chemistry property of lipophilicity vs. lipophobicity regarding PFOA and organohalogens. even after i had gone to lengths explaining the chemistry behind it! Smokefoot, dealing with your bs is what drove me to cite so many primary sources. i happily shift the blame to you. i am so thankful Cacycle actually pointed out the policy of Wikipedia on sources to me, where you could have assisted me as i was a new editor. i can't help but conclude that you fight against the very core of Wikipedia: consensus. i find it impossible to reach consensus with you, despite trying.[10] i remain deeply suspicious of the motives behind your edits, i regret to say. -Shootbamboo (talk) 20:46, 25 October 2008 (UTC)

Error in Synthesis?[edit]

I added a citation needed tag for "carboxylation of perfluoroiodooctane" because it strikes me that adding a carboxyl group (via replacement of the iodine) to perfluoroiodooctane would actually give the 9-carbon chain compound perflurononanoic acid. But maybe something else is going on, or there is a catalyst involved in the process that goes completely unmentioned, that cleaves CF2I (instead of I) and replaces it with COOH. Without a citation, who knows? Zaphraud (talk) 00:46, 28 October 2008 (UTC)

Additional note: The citation listed seems to be, direct quote: PFCAs have been manufactured as salts by four distinct synthesis routes, namely: electrochemical fluorination (ECF), fluorotelomer iodide oxidation, fluorotelomer olefin oxidation, and fluorotelomer iodide carboxylation.

I think someone pulled a boner when they were paraphrasing, however carboxylation is also mentioned in japanese patent application 02169553. Anyone care to look that up and see if there are missing pieces to this? Zaphraud (talk) 01:09, 28 October 2008 (UTC)

Zaphraud you are absolutely right about the synthesis yielding PFNA. Regrettably, I made this error in haste. You can see where I thought my source was from on my talk page where I said that the "...second page of the Supplemental Information to the 2006 Prevedouros article - "Sources, Fate, and Transport of Perfluorocarboxylates" because it has equations for all 4 PFOA industrial synthesis routes." But I was wrong the SI shows two equations yielding PFNA instead of all 4 yielding PFOA. In my defense, I was in a rush to "get down the page" to the issues relevant to exposed people. I come at it from this perspective - I try to make edits that exposed people probably care about most - and the details of the synthesis just aren't striking for those people in Ohio or WV. But still, as a chemist I shouldn't have made the mistake. I regret it. Thanks for catching it. But you can **** off with the lude comment about copyright issues, until you show me some policy, because when I was an undergrad writing reviews of articles for my professor to look over I ran into this issue repeatedly and received blessings for text I was fearful crossed the line.

in full:

PFOA has four main synthesis routes: electrochemical fluorination of octanoic acid, oxidation of perfluoroiodooctane, carboxylation of perfluoroiodooctane, and fluorotelomer olefin oxidation.[1]
I shamelessly copied the format of the sentence. If that is crossing the line, let me know. I do not appreciate your childish uncivil manner of raising the issue. -Shootbamboo (talk) 02:34, 28 October 2008 (UTC)

I specified octanoic acid fluoride in the page bc that is the reactant in the source - for more details on the ECF here is Fluorinated Higher Carboxylic Acids. 1994. kirk-othmer encyc. of chem. tech. stating "many of the perfluoroalkyl carboxylic acids were first prepared by the electrochemical fluorination (ECF) method of the corresponding carboxylic acids. In ECF acid chlorides are converted to the corresponding perfluoroacid fluorides..." so it looks like octanoic acid -> octanoic acid chloride -> octanoic acid fluoride -> PFOA for the full route of ECF synthesis. -Shootbamboo (talk) 03:03, 28 October 2008 (UTC)

I don't think I ever meant to imply any ethical or copyright violation occurred with regard to this issue; rather, merely that copy-paste may have been a possible source of the error. Just wanted to clear that up. Zaphraud (talk) 21:04, 10 February 2011 (UTC)

lower birth weights[edit]

I read the American Council on Science and Health's response to the "low birth weight in babies" claim, and the reference to the response should be removed because ACSH utilized very faulty reasoning. The point of the study was to examine how the average birth weight changes as a result of PFOA exposure. This particular study found a lower average. Plain and simple. Maybe it is true that by the numbers, 4 ounces lower is within the normal birth weight range, but this is where the flaw is - to claim that the 4 ounces lower weight is "still normal"; they are different populations in the statistics sense of the word. What's normal for one is irrelevant to different groups.

12.187.137.34 (talk) 03:53, 9 November 2008 (UTC)

Thanks for your comments, I invite you to join Wikipedia and establish an account, as I am also relatively new. Thinking that sources employ faulty reasoning is fine to do, but is not justification for deleting them. That being said, I'm going to reinstate the material. Thanks for your interest. -Shootbamboo (talk) 23:44, 9 November 2008 (UTC)
While it is true that they are two populations, in that they are two different sets of data, comparing "distinct" populations is not uncommon. In this case one is a "control" one is the variable. It should be noted, just because you changed a variable (in this case exposure to POFA), it does not make the populations distinct (this is why I put distinct in quotes earlier). Just because the mean of the populations differ is not enough to say the populations are statistically different. You must do more advanced testing, since randomly picked samples will differ even if they are from identical populations. What matters is they fall with in the normal range. On top of that if you look at specifically the weight study @ CI95% the weight would range –149g to +10g. This means the average falls with in that range 95% of the time. This is not good because with an avg. of -69g, your VARIANCE is larger than the average (your value is roughly 80g) so the average is better given as -69g +/- 80g. This means there is a significant proability that this value (the mean) is actually an increase in weight when extended to infinity, implying there is a chance that in fact PFOA INCREASES birthweight. What I could read of the article didn't give me enough information to do a test to determine if the values are SIGNIFICANTLY DIFFERENT, not different just by chance which is a foundation of the reason for statistics. So in summary I do think that it is a valid contributionPedroDaGr8 (talk) 01:09, 21 November 2008 (UTC)
since you are so interested in this issue, check out these discussions (that i had previously cited) in the page without incorporating any detail. "Guest editorial: biomarkers of perfluorinated chemicals and birth weight""PFOS and PFOA in humans: new study links prenatal exposure to lower birth weight""Perfluoroalkane acids and fetal growth""Perfluoroalkane acids: Apelberg et al. respond" you may find something that backs up your ideas and then you could cite it. please do it in a way that does not violate the WP:NPOV policy (thus i recommend that you should probably cite argument and rebuttal if they are included in the discussions.) thanks for your interest. -Shootbamboo (talk) 03:48, 21 November 2008 (UTC)

2007 EPA study and the 3 bioassays[edit]

Hi, I had trouble verifying this sentence:

A 2007 USEPA toxicology review states, regarding PFOA and PFOS, that "neither compound has been shown to be mutagenic in a variety of assays" and then cites three sources: one authored by 3M, one authored by 3M, DuPont, Covance, Atofina, and Ineos Chlor, and one from the USEPA.[19]

(19 is Lau 2007 from Toxi Sci.) which appears in Perfluorooctanoic acid#Animal data. I used the Find function and couldn't pick up the quoted text. II | (t - c) 07:37, 16 April 2009 (UTC)

Meh, found it. Looks like a bug in Foxit's Find feature where words which are broken into new lines don't get picked up by Find. II | (t - c) 07:42, 16 April 2009 (UTC)

I still might have a bit of an issue with the way that statement is presented. It might leave the reader with the impression that the EPA is hiding something. Yet the preceding sentence states that "FOA has been shown to induce hepatocellular adenomas, Leydig cell tumors, and pancreatic acinar cell tumors in male Sprague–Dawley rats (Biegel et al., 2001; Cook et al., 1992; Sibinski, 1987)." Throughout the article Lau seems fairly upfront about the health risks posed by PFOA. There are non-mutagenic carcinogens, by the way. II | (t - c) 08:01, 16 April 2009 (UTC)

I agree the sentence wasn't presented appropriately. The affiliations of all the authors on those sources was not mentioned in the cited source, so I made this edit[11]. Also, if it helps, there is a url to the full pdf of Lau 2007 in the references. -Shootbamboo (talk) 01:54, 17 April 2009 (UTC)

Sources to People: Food Contact Surfaces and Bias[edit]

I want to thoroughly vet the data pertaining to non-stick coatings in cooking pans and pots, as that is clearly a major entry point for this topic.

In the line referring to non-stick pans as an exposure source:

Overall, PTFE cookware is considered an insignificant exposure source of PFOA.[46][56]

Reference 56 is a Consumer Reports study which does not contain any reliable, hard data. All it says is that "Working with a lab that specializes in PFOA, we..." and "The highest level was about 100 times lower than levels that animal studies suggest are of concern for ongoing exposure to PFOA." What numbers are these? What are they referencing for those claims? Using this as a source for such a claim is not reasonable. Incidentally, this claim is being posted on blogs around the net by DuPont reps, and that alone makes it somewhat questionable (find the consumer reports link in the Comments of this article and google for it--they're using the same form letter to post it everywhere).

Reference 46 does suggest that it's not a MAJOR source, but by no means does it say it is an 'insignificant' source:

The greatest portion of the chronic exposure to PFOS and PFOA is likely to result from the intake of contaminated foods, including drinking water. Consumer products cause a minor portion of the consumer exposure to PFOS and PFOA. Of these, it is mainly impregnation sprays, treated carpets in homes, and coated food contact materials that may lead to consumer exposure to PFOS and PFOA.

For this reason, I propose the following change:

FROM: Overall, PTFE cookware is considered an insignificant exposure source of PFOA.

TO: PTFE cookware is not known to be a major source of PFOA. —Preceding unsigned comment added by 71.67.111.9 (talk) 15:15, 17 October 2009 (UTC)

On page 259 of Trudel et al. (Reference 46) it states that modeling showed PFOA migration (into food from PTFE-coated cookware) did not cause "significant exposure... that is... less than 1% in any of the scenarios". Thus insignificant is not a synthesis as you appear to suggest—let alone biased =). Read this 2009 study if you're interested. (Findings on page 40 showed PTFE cookware PFOA levels ranged from non-detect (<1.5) to 4 parts per billion—which is less than the 4–75 Begley et al. found.) See this take on the 2009 study and a table extracted from it. (Right now it is only in the external links section, and is not cited in the article itself.) -Shootbamboo (talk) 16:45, 17 October 2009 (UTC)
Relevant table from study referenced above now in article. -Shootbamboo (talk) 19:13, 14 November 2009 (UTC)

Alternatives; shorter perfluoroalkyl chain compounds[edit]

C&EN has a Fluorochemicals Go Short article on the new PFOA replacements which could be interesting. We should perhaps have a section on alternatives, although personally I can't see anything which is indefinitely persistent as an acceptable alternative. I would have added the article, but I'm not up for the formatting and it doesn't seem to have a PMID or doi (emailed C&EN about their odd lack of dois). II | (t - c) 19:07, 9 February 2010 (UTC)

I agree, at least a sentence would be useful. Scotchgard and perfluorobutanesulfonic acid deal with this shortening on 3M's part. So perhaps an article on perfluorohexanoic acid to explain the relevance would be useful.[12] There have been some toxicity studies on the C6 carboxylate and degradation studies of 6:2 fluorotelomer alcohol lately because of this shift. Production/sales figures on the C6 based stuff would be nice to get an idea of how relevant it is. Also, I'd like to see some data on how much C8/PFOA is produced. Upon glancing at the DuPont study (doi:10.1016/j.chroma.2006.01.086) DuPont references in the link above, the table is missing the LOD for PFOA, and the LOQ is 2 parts per million, or 2,000 parts per billion. In my opinion, DuPont is in a tough spot, because telomerization is a polymerization—thus it seems next to impossible to synthesize oligomers mostly containing n taxogens without appreciable product with n+1. While a different telomerization, Surflon S-111 gives a feel for one distribution. -Shootbamboo (talk) 21:55, 10 February 2010 (UTC)
I just read Uses of Perfluorinated Substances by Walters & Santillo 2006 from Greenpeace Laboratories. Despite Greenpeace's reputation, I think it is a decent source and at the end they summarize alternatives with a table and comment that "many of these are either other fluorinated substances or novel chemistries for which there is a lack of toxicological information". II | (t - c) 08:00, 20 May 2010 (UTC)

Poor sourcing[edit]

There is a lot of human health information in the article sourced to sources which fail WP:MEDRS, and a lot of dwelling on sources which are - in WP:MEDRS terms - WP:PRIMARY sources. I am attempting to reduce this problem and will introduce some secondary sourcing if I can find it ... Alexbrn talk|contribs|COI 11:00, 3 November 2013 (UTC)

Your massive removal of content and your arguments remind me on industry positions and tactique. --Leyo 20:47, 3 November 2013 (UTC)
Pardon? Alexbrn talk|contribs|COI 20:59, 3 November 2013 (UTC)
Industry representatives keep critisizing available studies and emphasizing that effects of a chemical are not understood and research is needed. And your added statement is not fundamentally different. This is their delaying tactics concerning a potential ban or other regulation. Sorry for being direct. As you do not seem to be from the field, it might well be that you were unaware of this issue and it was thus not your intention. --Leyo 21:33, 3 November 2013 (UTC)
I'm all for keeping our articles well-sourced but these edits have essentially been using a false understanding of our sourcing requirements to erase a lot of negative information from this article. Articles from peer-reviewed journals are acceptable and, used with proper caution, primary studies are as well. Gandydancer (talk) 22:17, 3 November 2013 (UTC)
For biomedical information good secondary sources are really required; primaries can be used carefully as an adjunct to them. This is all set out in WP:MEDRS. Whether the result comes out "negative" or "positive" is not our concern - we must follow the reliable sources. Alexbrn talk|contribs|COI 22:21, 3 November 2013 (UTC)
IMO, MEDRS is for medical research only. No one is going to be doing an RCT on anyone with PFOA anytime in the forseeable future. Thus, WP:SCIRS and WP:PRIMARY apply here. Let's please not lose sight of the purposes of our guidelines. Biosthmors (talk) pls notify me (i.e. {{U}}) while signing a reply, thx 00:20, 4 November 2013 (UTC)
Well, the guidelines does say it applies to "medical and health-related content in any type of article", which seems pretty clear to me. Perhaps the best thing to do is get a view from WT:MED - I'll raise a query. Alexbrn talk|contribs|COI 06:17, 4 November 2013 (UTC)
That would be quite a pro-MEDRS constituency, would it not? Biosthmors (talk) pls notify me (i.e. {{U}}) while signing a reply, thx 10:35, 4 November 2013 (UTC)
Biosthmors – when it's appropriate, of course! The expertise we seek is knowing where the line is drawn, as if that really needs to be asked. Alexbrn talk|contribs|COI 10:39, 4 November 2013 (UTC)

Please discuss your proposed changes, Alexbrn[edit]

I have reverted the massive removal of content and sources from this article by Alexbrn. Wikipedia policy does not prohibit using primary-source studies in articles, and to the extent that sections of the article might need to be rewritten, it should be done so carefully and via consensus. I disagree with the blanket, wholesale removal of dozens of peer-reviewed sources and tens of thousands of bytes of text in one fell swoop without more discussion than a nebulous claim of "unreliable source." Consider this the R in WP:BRD. NorthBySouthBaranof (talk) 06:06, 4 November 2013 (UTC)

Hi there. From my perspective the key objective is not to have bogus health information in article; thr risk comes (among other things) from using poor sources, from misrepresenting sources, and from giving undue weight to certain material. As reverter, the onus is on you to justify the reversion. So let's start at the top: in the "Toxicology data" section Wikipedia states, in her own voice,

PFOA is a carcinogen, liver toxicant, a developmental toxicant, an immune system toxicant, and also exerts hormonal effects including alteration of thyroid hormone levels.

What reliable source backs these sweeping claims? It looks to me like a bit of a misrepresentation of the paper cited. Alexbrn talk|contribs|COI 06:41, 4 November 2013 (UTC)
I agree with you on this one. In fact, I'd agree that there seems to be plenty in that entire section that needs to be looked at. Gandydancer (talk) 08:49, 4 November 2013 (UTC)
I did actually check the sources before removing them, and left an edit summary trying accurately to state my reasons - it took quite a while ... Alexbrn talk|contribs|COI 08:53, 4 November 2013 (UTC)

Good sources[edit]

Searching around I find:

So these are the strong sources (I will add more if I find them) concluding, in essence, that the human health effects of PFOA are unknown. However, that doesn't stop Wikipedia contradicting this by giving us a wealth of information stating and implying health effects, in a great spree of original research based on primary sources. I propose we remove any primary or weak source which runs against the grain of the conclusions above. Alexbrn talk|contribs|COI 08:04, 4 November 2013 (UTC)

I can't understand your reasoning. Both of the above sources state that we do not yet have enough information to decide for certain on whether or not this chemical is causing health effects. To me, that seems all the more reason to include any new information that comes out in the form of primary studies. I'm not sure what you mean by "weak sources"--what do you mean? Gandydancer (talk) 09:09, 4 November 2013 (UTC)
The short answer is, because WP:MEDRS says so. The longer answer is, that by doing so we are engaging in original research. When primary sources are discussed in real secondary sources they are assessed in all kinds of ways: methodological rigour, applicability, comparability, risks of bias, etc. Many are discarded and some few usually synthesized into a conclusion. Wikipedia is attempting to do this itself, but in an inexpert, unreliable way: classic OR and SYNTHESIS. We (editors) have picked out and paraded primary sources to "paint a picture" of the current state of PFOA effects on human health. We should instead rely on independent, reliable secondary sourced precisely to avoid stating or implying possibly bogus health information. There is also the question of weight. If some primary source has not received significant attention from a secondary source, on what basis do we include it? The MO for the article as it was seems to have been to assembly a laundry-list of scary sounding health information. The result is an article which is, in my view, an embarrassment to Wikipedia.
A weak source is a source which does not meet the threefold WP requirement for a good source: independent, secondary, reliable. Alexbrn talk|contribs|COI 09:55, 4 November 2013 (UTC)
For health claims, please apply WP:MEDRS when choosing sources, for non-health claims, please apply WP:RS. Lesion (talk) 10:07, 4 November 2013 (UTC)
How does one differentiate between "health" and "non-health" claims for the purposes of executing this vision? ;-) I think we might just best conclude this would be a false dichotomy, IMO. Maybe someone could prove me wrong though. =) Biosthmors (talk) pls notify me (i.e. {{U}}) while signing a reply, thx 15:22, 4 November 2013 (UTC)
I wonder if it would help to change the heading to "Research"? Gandydancer (talk) 15:28, 4 November 2013 (UTC)
A fix the the "Toxicology data" section (after removing the first sentence) would be to call it "Toxicological animal studies" (or somesuch), and move it away from the "Health" section. Alexbrn talk|contribs|COI 15:34, 4 November 2013 (UTC)

Some recent review studies[edit]

Some of them might be useful to update the article based on secondary sources. --Leyo 09:39, 4 November 2013 (UTC)

Cool - may I ask what search method you used to locate these? Alexbrn talk|contribs|COI 09:55, 4 November 2013 (UTC)
A rather simple one: keywords pfoa and review in Web of Knowledge, then picked the ones that seemed relevant based on title and abstract among the recent publications. --Leyo 10:51, 4 November 2013 (UTC)
One could also just do the keyword for PFOA then filter by reviews. ;-) Biosthmors (talk) pls notify me (i.e. {{U}}) while signing a reply, thx 11:01, 5 November 2013 (UTC)