Talk:Polychlorinated biphenyl

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[edit] Needs references

Many statements in this article need references. I will try to provide them as I have time, but any help is appreciated. Jed 20:06, 9 April 2007 (UTC)

[edit] History

moved from main article: "It's funny how this article is couched in terms of PCBs being pollutants! Indeed, they are when they escape into the environment, but initially they were a rather powerful enabling technology in electrical power generation, were they not?"

-Hindsight is always 20/20. Excellent chemicals for what they were originally used for. No one saw the long term health effects.

- Actually, the known human health effects were revealed in the late 1930s in something called the Drinker Study, conducted for a company called Halowax (which used PCB as an ingredient). GE was present at the meeting, since it was a kind of electrical industry powwow. The Drinker Study indicated that therre was liver necrosis in workers exposed to the substance. So from right at the beginning of commercial production, there was the long term health issue.

This is from my 1994 article in Sierra magazine...

"Drinker presented his results at a 1937 meeting at Harvard attended by Monsanto, GE, Halowax, the U.S. Public Health Service, and state health officials from Massachusetts and Connecticut. Like the Halowax workers, Drinker's test rats had suffered severe liver damage. "These experiments leave no doubt as to the possibility of systemic effects from the chlorinated napthalenes and chlorinated diphenyls," he concluded.

"Minutes of a discussion held later that day include a telling remark by GE official F. R. Kaimer: "We had 50 other men in very bad condition as far as the acne was concerned," he told the group. "The first reaction that several of our executives had was to throw [the PCB] out - get it out of our plant. But that was easily said but not so easily done. We might just as well have thrown our business to the four winds and said, 'We'll close up', because there was no substitute and there is none today in spite of all the efforts we have made through our own research laboratories to find one."

"Sanford Brown, the president of Halowax, concluded the meeting with another thought that would echo through the next five decades. Brown stressed the "necessity of not creating mob hysteria on the part of workmen in the plants" where chemical-safety inspections were being made. Problems with PCBs and napthalenes, he predicted, "may continue, probably will continue for years." The silence of those at the meeting ensured that effect.

"Meanwhile, the damning evidence continued to spill out of corporate laboratories. A 1938 study of PCB-oil mixtures manufactured by Westinghouse and GE demonstrated that liver damage could be caused by skin contact alone, and called for the "greatest personal hygiene" in minimizing exposure. In further research for Monsanto, Drinker warned that adequate ventilation was necessary when handling the chemicals. By 1951, Monsanto also had in its files a 1947 scientific finding that there was "need to give warning" about PCBs because 'the toxicity of those compounds has been repeatedly demonstrated'."


This is actually quite interesting. Is there some way some of this information can be included in the history section without copyright issues? [pared down, perhaps] Jed 21:06, 20 January 2007 (UTC)

The last paragraph in the History section (discussing issues concerning a Westinghouse plant) is written in an informal style and is thus inappropriate for a formal encyclopedia entry. Parts of it also appear opinionated, and the section as a whole is uncited (thus rendering it worthless to someone like me doing research). While not wanting to run roughshod over someone else's work-in-progress (I hope), I suggest that this section be deleted or modified and cited. 64.81.3.74 18:45, 2 May 2007 (UTC)Jonathan

I just created a separate section for the large scale PCB contamination sites - included so far are only the Hudson River and Indiana, to be added later are New Bedford Harbor, MA (Superfund priority site #5 - I looked it up once), and the just-cleaned up Housatonic River in MA/CT. Jed 18:59, 2 May 2007 (UTC)

[edit] Chemical Degradation of PCBs

I changed the earlier statement regarding solar excitation and degradation of PCBs in the atmosphere. Work dating back to 1996 (Anderson et al, Environ. Sci. Technol., 1996, 30, 1756-1763) shows that OH radicals are the major removal pathway in the atmosphere. Work has been done to sensitize PCBs to solar wavelengths (Manzano et al, Chemosphere, 2004, 57, 645-654), but if this takes place at all in the atmosphere, it would be negligable compared to the OH radical pathway. --dil 01:24, 23 November 2005 (UTC) pcb is very usefull we cant get rid of it...

[edit] Known human carcinogen

I made reference to PCB's being classified by the National Toxicology Program as known human carcinogens based on Technical Reports 520 and 531. They can be found here http://ntp-server.niehs.nih.gov/ntpweb/index.cfm?objectid=08481142-D3A0-C8AE-408773AC4B6D89C5

Which someone has since removed for some unknown reason. I suggest reverting it back to include your addition unless they can provide a good reason for removing it. dil 20:12, 27 October 2006 (UTC)
While making a routine repair to vandalism I noticed that removal as quite clearly being unwarranted. So I reverted it too. Samuel Erau 16:25, 30 October 2006 (UTC)

[edit] NPOV discussion

This article only discusses the claim that PCBs are toxic/carcinogenic when there is evidence that it is neither. If you claim that it is fact since PCBs are on a government list as a carcinogen, please research saccarine and see how it was on a government list at one time also.
References:

http://www.junkscience.com/mar99/kimbro.htm
http://query.nytimes.com/gst/fullpage.html?sec=health&res=9A03E7DB1E3FF933A25750C0A96F958260
Beyond the fact that the current consensus generally seems to be in favor of the fact that PCBs are indeed harmful, the article mentions that this claim is a source of some controversy. Clearly the article needs more information on the controversy and cited sources, though. Perhaps it'd be best to do those things, then pull the NPOV tag? --FreelanceWizard 23:55, 1 July 2006 (UTC)

[edit] Removal of NPOV Discussion

I have removed the NPOV disclaimer. PCB are comprhensively studied carcinogens, and the references provided by abover poster are a GE funded epidimeological syudy, and a New York Times review article of said study. Below please find several recent references from the scientific literature detailed toxicity and mechanism for PCB.

Ludewig, G. Cancer initiation by PCBs. PCBs, Recent Advances in Environmental Toxicology and Health Effects (2001), 337-354.

Tohyama, C.; Nishimura, Noriko; Yonemoto, J. Differential disrupting effects of polychlorinated biphenyl isomers on homeostasis of thyroid hormone and retinoid in mice. Organohalogen Compounds (2003), 63 401-404.

Mechanisms of hepatic tumor promotion by polychlorinated biphenyl mixtures. Dean, Charles Edward, Jr. Colorado State Univ., Fort Collins, CO, USA. Avail. UMI, Order No. DA3107075. (2003), 173 pp. From: Diss. Abstr. Int., B 2004, 64(9), 4295. Dissertation.

I agree that the NPOV tag should be removed. A significant number of peer-reviewed references regarding the toxicity of PCB's have been cited; two newspaper articles stating that they are not have been cited. From Wikipedia's own NPOV page: "If a viewpoint is held by an extremely small (or vastly limited) minority, it doesn't belong in Wikipedia (except perhaps in some ancillary article) regardless of whether it's true or not; and regardless of whether you can prove it or not." Unless those who believe they aren't toxic can show a more significant body of work, the tag simply doesn't belong here. dil 01:58, 25 July 2006 (UTC)
I also agree per above comments. It looks like the POV tag may have been erroneously restored in anti-vandal effort.Qball6 23:10, 24 August 2006 (UTC)

[edit] GE section

I added a section about the GE contamination of the Hudson River, and an exteranl link that discusses that controversy in more detail.KonaScout 19:17, 28 September 2006 (UTC)

This still doesn't have a reference, so I removed the entire paragraph. It can be put back in with a source. Superm401 - Talk 11:05, 30 December 2007 (UTC)

[edit] olestra

Does someone want to confirm or refute the assertion that olestra can treat PCB poisoning? I read it somewhere, and think it might be interesting to include, but I don't have time to be responsible and fact-check it.--Joel 09:00, 8 October 2006 (UTC)

I work with PCBs and chlorinated dioxins, and we have been told to eat Olestra in case of accidental exposure. There is a reference on the dioxin page to Olestra therapy, which I will copy over. Jed 22:10, 14 November 2006 (UTC)

I work on effects of prenatal exposure to PCBs and this is the first time I have heard of Olestra in the field. I went through a fast search in PubMed and there is only one paper on Olestra having effects after Arochlor poisoning. Redgrave TG, Wallace P, Jandacek RJ, Tso P. Treatment with a dietary fat substitute decreased Arochlor 1254 contamination in an obese diabetic male. J Nutr Biochem. 2005 Jun;16(6):383-4. Piedrafita 18:17, 8 February 2007 (UTC)

Ah, but there are a few articles about Olestra increasing dioxin (TCDD) excretion - I have presumed that dioxins and PCBs behave pharmacokinetically similar (which is essentially the case). Geusau A, Tschachler E, Meixner M, Sandermann S, Papke O, Wolf C, Valic E, Stingl G, McLachlan M. Olestra increases faecal excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Lancet. 1999 Oct 9;354(9186):1266-7. Olestra has also been used in a clinical setting for TCDD exposure: Geusau A, Abraham K, Geissler K, Sator MO, Stingl G, Tschachler E. Severe 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) intoxication: clinical and laboratory effects. Environ Health Perspect. 2001 Aug;109(8):865-9. [1] Jed 02:49, 9 February 2007 (UTC)

I don't believe this is so across the board for PCBs. All dioxins, by virtue of their structure, are planar due to the dual oxygen linkage between the chlorinated rings. PCBs have a single linkage and therefore the rings may be able to rotate outside of a coplanar configuration. This is mostly dependent on the positions of the substituent chlorines. For example, the rings will be forced out of a coplanar configuration if there are multiple ortho chlorines. This leads to a wide variation in biological effects between various PCB congeners. dil 14:35, 9 February 2007 (UTC)
You are of course absolutely correct. I was thinking of the non-ortho-substituted PCBs, which are considered the most toxic (ie PCB-77: 3,3',4,4'-tetraCB or PCB-126: 3,3',4,4',5-pentaCB). The ortho substituted PCBs are quite non-coplanar, and thus have different toxicokinetics. However, they may have similar hydrophobicities, which I think is probably the relevant parameter in regards to solubility in olestra. Jed 21:54, 28 February 2007 (UTC)

[edit] Monsanto As Sole Producer

The article suggested that Monsanto was the "major" manufacturer of PCBs and then stated that GE also marketed PCB products, which in turn suggests that GE was another North American manufacturer of PCBs. This is inaccurate. After it purchased the Swann Chemical Company in 1930, the sole manufacturing facilities for PCBs in North America were the two Monsanto PCB plants, one located in Anniston, Alabama and one located in Sauget (formerly Monsanto), Illinois. I have edited that passage accordingly. It is also the case that PCB production halted at the Anniston plant in 1971 but continued in Sauget until 1977 (just before the effective date of the Toxic Substances Control Act (TSCA) banning PCB production altogether).

Bhamlaw 18:26, 2 April 2007 (UTC)

[edit] Are PCBs banned (in the U.S.) or aren't they?

Currently, in the "History" section the article says

Concern over the toxicity and persistence (chemical stability) of PCBs in the environment led the United States Congress to ban their domestic production in 1977, although some use continues in closed systems such as capacitors and transformers.

I put a "{{disputable}} tag on this sentence, as it seems self-contradictory. If Congress banned their domestic production, how can "some uses continue"? Are the chemicals imported? or was the ban not complete, with some exceptions made? Inquiring minds would like to know.

While I was at it, I removed the word dielectric from its use in tranformers, as the chemical is used there as an insulator (dielectrics are for capacitors). +ILike2BeAnonymous 18:42, 16 July 2007 (UTC)

I don't see these as being contradictory at all. In fact, it's explained pretty clearly if you read the paragraphs immediately before and after the one you've tagged:
"From 1973 their use was banned in "open" or "dissipative" sources..."
Followed by...
"...led the United States Congress to ban their domestic production in 1977..."
Followed by...
"The use of PCBs in "closed" uses include..."
A production ban isn't the same thing as banning its use and, while use in open applications has, use in closed application hasn't been banned. Unless you've got some compelling reason to keep it, I'm going to remove the disputed tag. dil 12:36, 17 July 2007 (UTC)
Well, OK, but let me just ask an obvious question: if there's a ban on production, then where does the stuff come from? Abroad? In other words, how can you use something without also producing it? It doesn't come from holes in the ground ... +ILike2BeAnonymous 17:43, 17 July 2007 (UTC)
It's already there - the transformers that were manufactured while PCB's could still be legally produced are still in use today. Companies weren't forced to remove old transformers and replace them with PCB-free transformers when the production or open system ues bans went into effect. I'm not sure why you're equating use with production, as they're two totally separate concepts; it's leading to unneccesary confusion. dil 17:08, 18 July 2007 (UTC)

The simple explanation for why production is banned, but closed system uses continue, is that PCBs remain in large electrical components whose useful life spans decades. The ban did not require electrical utilities, for example, to remove 10 year old transformers with a useful life of 50 years from power poles. Many older transformers and other large electrical components that contained PCBs that were manufactured when it was still legal remain in use. Believe me (I'm a lawyer specializing in PCB litigation), the U.S. ban absolutely prohibits the manufacture, importation, or sale of PCBs for new uses.

Bhamlaw 20:35, 17 July 2007 (UTC)

I believe you. Now we're getting somewhere. So PCBs have essentially been grandfathered in for certain uses—I believe that's the correct term, right? So the article ought to be edited to convey this; it's not clear at all the way it's written now. +ILike2BeAnonymous 05:49, 18 July 2007 (UTC)
Sorry, didn't see this before I replied above. dil 17:11, 18 July 2007 (UTC)

[edit] Featured Article Status

Where are we at now and what needs to be done to make this a featured article? dil 17:14, 18 July 2007 (UTC)

[edit] List of trade names

Would a list of trade names under which PCBs were manufactured and sold be of any use? Jed (talk) 04:12, 7 March 2008 (UTC)

How different is it from Polychlorinated biphenyl#Alternative_names? - Neparis (talk) 02:39, 8 March 2008 (UTC)
Oops. Not enough to make a difference. A few extra names, but it's probably just clutter. 03:45, 12 March 2008 (UTC) —Preceding unsigned comment added by Jedgold (talk • contribs)

[edit] Salmon

Perhaps this may warrant mention : [2] —Preceding unsigned comment added by 4.159.77.35 (talk) 15:19, 30 March 2008 (UTC)