Talk:Methylmercury

Chemicals B‑class High‑importance

	This article is within the scope of WikiProject Chemicals, a daughter project of WikiProject Chemistry, which aims to improve Wikipedia's coverage of chemicals. To participate, help improve this article or visit the project page for details on the project.ChemicalsWikipedia:WikiProject ChemicalsTemplate:WikiProject Chemicalschemicals articles
B	This article has been rated as B-class on Wikipedia's content assessment scale.
High	This article has been rated as High-importance on the project's importance scale.

Article renaming

I moved this article here from methyl mercury in what I thought would be an uncontroversial move. For what it's worth, I wasn't just taking part in some sort of Holy Quest to change the spacing; I was also here to clean the stub a bit. It seems that the move has prompted rather more discussion than I expected, so here is my reasoning.

Methylmercury is in line with IUPAC nomenclature standards. (PDF.)
Methylmercury is more often used on the WWW, based on its Google results:
- "Methylmercury" 120,000 results.
- "Methyl mercury" 64,500 results, and a prompt for Did you mean: "methylmercury".
On PubMed, methylmercury draws 3273 hits, versus 775 for methyl mercury.

As far as I know, there's no US versus British English issue here, so I shouldn't be treading on those sensitive toes. I changed the wikilinks in articles with methyl mercury because that's standard practice after renaming an article; I didn't use piped links because I didn't expect any controversy. Frankly, I still don't see the harm in the change. If someone feels this should go to RfC for further consultation, that's fine. --TenOfAllTrades (talk/contrib) 18:19, 2 May 2005 (UTC)[reply]

One more thought—this name is also consistent with the name of our existing article at dimethylmercury. Cheers, TenOfAllTrades (talk/contrib) 21:13, 2 May 2005 (UTC)[reply]

Expert review is needed

Methylmercury is formed mainly by a process called biomethylation. which is carried out by sulfate reducing bacteria, not as written in the article --Tarawneh 06:32, 19 November 2005 (UTC)[reply]

Unexplained reversion

I don't understand why the anonymous 205.208.227.31 removed the 3 JAN 06 material contributed by 160.93.167.240. The former person seems to have done some good stuff elsewhere in Wikipedia, so this was not vandalism. However I thought that the new material was valuable. I would like to see comment on this, especially from 160* so that I or someone more knowledgible could make a decision about reinstating what was removed. Myron 23:47, 10 January 2006 (UTC)[reply]

As the reversion remains unexplained, I have restored the material contributed by 160.93.167.240 and have reorganized it and added some sources. The article still calls for wikification and some more sources. Myron 02:23, 13 January 2006 (UTC)[reply]

Frequency of ill effects

Cut from article:

Several studies indicate that methylmercury is linked to subtle developmental deficits in children exposed in-utero such as loss of IQ points, and decreased performance in tests of language skills, memory function and attention deficits. Methylmercury exposure in adults has also been linked to increased risk of cardiovascular disease including heart attack. Some evidence also suggests that methylmercury can cause autoimmune effects in sensitive individuals. However, to date, methylmercury has not been linked to any specific neurologic or autoimmune disease. Although there is no doubt that methylmercury is toxic in several respects, including through exposure of the developing fetus, there is still some controversy as to the levels of methylmercury in the diet that can result in adverse effects.

This paragraph comes right after a passage which says this sort of thing is rarely seen. But the way it's worded implies than studies have found lots of this sort of thing happening.

Repair strategy:

Say that IF too much methylmercury gets in the uterus THEN children will suffer brain problems.
Explain where and when this has occurred. Like, any place other than Japan several decades ago?

(We also need to address mercury in fish (trace amounts are a hazard) vs. not eating fish (losing the nutrients may be a hazard too).)

I'm proposing an article on Mercury toxicity to address all of this:

Please help! --Uncle Ed 02:40, 9 December 2006 (UTC)[reply]

Ah, now I see why you added the redlink to the see also (I reverted one, I believe that see also sections should not contain redlinks, looks strange, but well). Yes, I think this is a good idea, thouhg I believe that covering it in mercury poisoning is also OK (making mercury toxicity a redirect there), these subjects are closely related. --Dirk Beetstra ^{T C} 10:50, 9 December 2006 (UTC)[reply]

I am the original author of the main text of the current version. The section of text presented above is correct as stated. There is no actual contradiction between the previous material that discusses frank poisoning episodes such as those in Minamata, and the deleted section that discusses more subtle effects such as increased risk of neurodevelopmental deficits, and increased risk of cardiovascular disease. In fact the distinction between those frank poisonings and these more subtle effects is explained in the paragraph the precedes the section of text in question. I strongly suggest that the current version be retained.

As above, I am the original author of the main text of the current version. I have deleted the statement that methylmercury is lipid soluble. This is not correct. In fact, methylmercury is found in much higher concentrations in fish muscle tissue than in fatty tissue. It is well absorbed and can pass the blood-brain and placental barriers because when it is bound to the amino acid cysteine, the complex is recognized by the neutral amino acid carrier as the amino acid methionine and passes through cell membranes bound to the carrier. This (and not fat solubility) is also the likely reason that it has a relatively long half-lifeI have also deleted the wording immediately following this statement that talks about absorption in the gastro-intestinal tract. This information is repeated in the following paragraph. 6, August 2007

Bioaccumulation and Retention in Aquatic Organisms

The current version states that bioaccumulation in aquatic food chain occurs because of the half-life of 72 days in those organisms. This statement is not accompanied by a citation and even if correct for some organisms, is almost certainly a gross oversimplification since the food chain encompasses a wide range of organisms. The retention of methylmercury through the food chain is likely to be very different at different ends of the food chain. This needs specific expert review. —Preceding unsigned comment added by 160.93.74.210 (talk) 19:55, 19 May 2009 (UTC)[reply]

I have edited the section "Human Health" to read, "There are isolated reports of various clinical health effects in individuals who consume large amounts of fish..." As previously written, it referred to unspecified types of health effects and "subpopulations." This made it confusing with respect to the preceding discussion about subtle sub-clinical health effects discernible by comparing populations and not necessarily discernible in individuals. In this case the intent was to refer to adult (i.e., non-developmental) effects that are identifiable in individuals (and hence, clinical effects). That is the essence of citation 17. 160.93.105.218 (talk) 22:01, 19 January 2010 (UTC) 19, January 2009[reply]

Claims that no neurological diseases have been associated...

The POV statement saying that no neurological diseases have been associated, well, it's just not so:

From OSHA (source: http://www.osha.gov/dts/chemicalsampling/data/CH_250500.html)

SYMPTOM(s): Paresthesia, ataxia, dysarthria; vision, hearing disturbances; spastic, jerking; dizziness; salivation; lacrimation; nausea, vomiting, diarrhea, constipation; skin burns; emotional disturbances

Sure reads like some neurological diseases. — Preceding unsigned comment added by BodyPride (talk • contribs) 22:03, 29 October 2011 (UTC)[reply]

I am the author of the original version of this article. I have responded to the neutrality concern regarding the statement about no neurologic disease association with methylmercury. Although I did not write that statement, it seems that it was inserted with respect to specific neurologic diseases (as opposed to toxicological symptoms)such as autism. I have, therefore deleted the original text and inserted text dealing specifically with autism, stating that there is little evidence establishing a link. Given this change, I have removed the neutrality (POV) flag for this statement. I have also added text and citations about the potential mediating effects of omega-3 fatty acids and selenium on methylmercury toxicity. — Preceding unsigned comment added by 160.93.113.69 (talk) 16:22, 15 December 2011 (UTC)[reply]

HUMAN HEALTH EFFECTS - Low-Dose Clinical Effects The statement regarding the lack of large-scale and controlled studies of low-dose clinical effects is correct as written. There are no such studies in the literature and all such reports are anecdotal case-studies. I have, therefore, removed the neutrality (POV) flag from this statement. I have also removed the neutrality (POV) flag from the statement regarding uncertainty as to the level of methylmercury that results in adverse effects. This is a topic of active discussion in the scientific literature. The text I have added (with citations) regarding potential mediation of adverse effects from omega-3 fatty acids and selenium provides additional information justifying the uncertainty as to effect levels.

"A Related Cation"

Would anyone mind if we used a more accessible term? It may be accurate but if you don't already know what it means, it looks like a typo. 74.132.249.206 (talk) 21:06, 12 April 2012 (UTC)[reply]