[HN Gopher] The Dangers of Dimethylmercury (2019) ___________________________________________________________________ The Dangers of Dimethylmercury (2019) Author : caaqil Score : 54 points Date : 2022-01-22 15:51 UTC (7 hours ago) (HTM) web link (www.chemistryworld.com) (TXT) w3m dump (www.chemistryworld.com) | JoeyBananas wrote: | > OSHA fined Dartmouth $9,000 (PS6890) for what it considered the | institution's failure to provide adequate caution, particularly | about the shortcomings of disposable latex gloves. | | I would think that PhD. chemists would be responsible for buying | their own PPE. Also $9,000 is such a weirdly small number | vmception wrote: | And everyone's guidance was wrong at the time, so it doesnt | make sense. | | OSHA used the opportunity to make a statement that wouldnt be | fought, compared to if they tried this with a much higher fine. | michaelcampbell wrote: | > I would think that PhD. chemists would be responsible for | buying their own PPE. | | I wouldn't; why would you? | masklinn wrote: | Guessing / hoping they meant the chemists would be | responsible for determining / ordering PPE suiting what | they're working on, not that they're supposed to pay for it | out of pocket. | | Though from what I've heard about solid through sand buckets, | and pitted face-shields, and contents of lab fridges, I'd | think GP a bit optimistic. | pmoriarty wrote: | This reminds me of the tragic case (involving a different | compound) of Sheri Sangji[1], a research assistant at UCLA who | spilled a pyrophoric substance on her highly flammable synthetic | sweater that she was wearing instead of a lab coat. | | [1] - https://en.wikipedia.org/wiki/Sheri_Sangji_case | praptak wrote: | This stuff is scary when you think it could be used in Putin- | style assassinations. | vmception wrote: | The assassins are too scared to handle it too | | Coupled with the year long gap before death | | Its probably not an ideal choice | pumnikol wrote: | It is now assumed that this already happened, in 2011, in a | Bulgarian umbrella attack in Germany's crime capital, Hanover. | My somewhat unfounded guess is that the perpetrator himself | perished not too long after the victim, which would explain why | the case is still unsolved. | trutannus wrote: | Worked with a professor who knew this person. He talked about | this not infrequently. All the grad students knew of the story as | well, and would talk about it. Her death really shook up the NMR | community. It was the reason we never use DEM in our lab, and why | many try to avoid it at all costs even now. If I remember | properly, and this was over 10 years ago, the reason its commonly | used is to calibrate the spectrometers, so in some areas it gets | hard to avoid. | | Also, the article mentions you need nitrile gloves to protect | yourself from it. _This is not sufficient_ and is dangerously | misinformed. You need _silver shield gloves_ to protect yourself | from it. | kibwen wrote: | The article mentions it: | | _" The bulletin also urged that, aside from wearing a face | shield, anyone working with dimethylmercury should wear Silver | Shield laminate gloves beneath abrasion-resistant outer gloves. | [...] Sugden points out that, when dealing with toxic | substances, labs have shifted from latex gloves to nitrile | gloves, which are less porous"_ | User23 wrote: | If I were a chemist and I had to work with that satan's brew I | wouldn't trust any gloves. I'd want a proper waldo setup. | rotifer wrote: | > Also, the article mentions you need nitrile gloves to protect | yourself from it. | | I don't see that. With respect to an OSHA bulletin, the article | says: The bulletin also urged that, aside from | wearing a face shield, anyone working with dimethylmercury | should wear Silver Shield laminate gloves beneath abrasion- | resistant outer gloves. | | The mention of nitrile gloves is in a more general context: | Sugden points out that, when dealing with toxic substances, | labs have shifted from latex gloves to nitrile gloves, [...] | crdrost wrote: | Yeah I wouldn't even want nitrile gloves on with the stuff. | | It is worth explaining just what is wrong with it. Mercury of | course is a toxic compound, but kids used to crack mercury | thermometers in their mouths and suffer no consequences. | Pressure gauges came with exposed tubs of mercury and you | would get some on your hands and it was fine, even kind of | fun to play around with. Felters famously felt symptoms after | careers of using it, usually blamed on long term inhalation, | but it required a long time and lots of exposure to get to | that point. Many people received dental amalgams with mercury | bases and while there has always been a conspiracy theory | about it, it has never been acutely toxic enough to be | mainstream--the shift to other composites has instead been | driven by comfort (metal fillings conduct heat and cold at an | unnatural rate) and aesthetics (the new composites are white | instead of silvery). | | The basic reason is that the body does not eat metal and does | not know what to do with it largely. Even with the metals | that the body uses, like cobalt, it wraps every atom of | cobalt in a big old ring of carbon and that's Vitamin B12. | | Dimethyl mercury, is different from normal mercury, in a | similar way. The methyl groups are organic groups that your | body is much more willing to absorb and process. So the latex | is not protecting you nearly as much because latex is this | organic natural filter that lets things through... But also | your skin is not protecting you because this stuff can seep | into your skin via those methyl groups, your cells are just | like "oh you look interesting I can take you into my | chemistry." | | So yeah, milligrams are all it takes, tiny trace amounts: but | the reason that you don't think of it being quite that | dangerous is that your exposure to the liquid metal version | is an exposure to a form that your body is uniquely unsuited | to process or absorb. Water off a duck's back. Even though | the water contains neurotoxin, it just rolls right off. Even, | in our case, when ingested. But add these little methyl | groups, methylmercury and dimethylmercury and really any | organic mercury molecule, it gets real bad real fast because | it's no longer rolling off our backs, it's soaking into our | feathers. | aligray wrote: | Thank you very much for taking the time to write such a | fascinating comment! | DaveExeter wrote: | When I was a kid I would take the mercury from tilt- | switches and pour it from hand to hand. | | So heavy and shiny! | madengr wrote: | phkahler wrote: | So what is the mercury compound they put in multi-dose | vaccines? | | EDIT: Thiomersal, and it looks pretty organic. I've read | that it leaves the bloodstream quickly, but not seen solid | evidence that its leaving the body. | an1sotropy wrote: | from: https://www.cdc.gov/vaccinesafety/concerns/thimeros | al/index.... "Thimerosal contains ethylmercury, which is | cleared from the human body more quickly than | methylmercury, and is therefore less likely to cause any | harm." | pumnikol wrote: | It's a nice step in the right direction, for sure. But, | having worked paying jobs in both Chemistry and Product | Safety: Not counting latex, nitrile is the bare minimum, | really, when it comes to chemical resistivity, and it cannot | handle heat (> 40 degC). But hot surfaces are very common in | labs. Hands off of latex gloves, though! Not only are they no | good against most chemicals, they can fill up like a sponge | and soak your hands with them. | jonpalmisc wrote: | ChubbyEmu's video [1] on this was quite good. (As is the rest of | his channel, if this kind of stuff interests you.) | | [1] https://m.youtube.com/watch?v=NJ7M01jV058 | ngcc_hk wrote: | Whilst it becomes political now, lab accidents and lab protection | even for known risk is still happened. If you study something | intensively and it will leak out with more probabilities. | supernova87a wrote: | I think every blackboard organic chemistry class should be | required to be taught with multiple repeated asides about the | dangers of organometallic reagents. And other dangerous materials | too. It's not just pushing electrons around, it's fucking with | your life potentially. | | And they send you into lab with only folk-story level preparation | if you're lucky enough to have gotten that info from others, and | one day there is in front of you a bottle of organo-tin looking | not too dissimilar from any other less harmful reagent. Only | saved from danger by some slightly older grad student saying, "be | careful around that stuff" (again, if you're lucky). | | I myself only knew about, for example, the dangers of ether | bottles left for a long time, because of my own interest in | happening to read about it. Not a single person in my entire | undergrad/grad career mentioned it. Hydrofluoric acid. Other | nasty stuff, etc. | | It's a major oversight for student education -- to be taught the | dangers of the subject you're about to be exposed to in real | life. | ashtonkem wrote: | Even as a lay person I know that most fluorine molecules are | not to be messed with. | dheera wrote: | Uh, except the stuff you shove on your toothbrush? | | The high-dimensional surface of "threat to life" vs. molecule | structure is super, super, non-convex. | | Like H2O -> yay, H2O2 -> die, H2 + O2 -> fire | | Like methanol -> die, ethanol -> fun, propanol -> die, | butanol -> die, heptanol -> die, octanol -> die | ashtonkem wrote: | And that's why I said "most". | masklinn wrote: | > Uh, except the stuff you shove on your toothbrush? | | Fluoride is an exception, only in small quantities, and | only topically (lots of salts are toxic, and so are | concentrated solutions). | | By and large fluorine chemistry is a giant pile of nope, so | staying away from it is an excellent rule and quite far | from a "super, super, non-convex". | rakejake wrote: | My high-school chemistry teacher had this joke: "If you | drink Ethanol you dance around people, if you drink | Methanol, people end up dancing around you". For context, | certain communities in India have people dancing around the | funeral procession. | FreeFull wrote: | 1-Propanol acts like ethanol, but stronger, so you'll be | fine if you don't ingest too much. 2-Propanol on the other | hand (isopropyl alcohol) gets metabolised into acetone, | which isn't great. And the only difference between the two | is the way the atoms are arranged! | addaon wrote: | Yes. I've often heard (although it appears to be an open | question[1]) that chemists have a significantly shorter life | span than the general population. | | [1] https://pubs.acs.org/doi/10.1021/cen-v049n010.p005 | Natsu wrote: | Yeah, most of the time I've read about such compounds it was | via blogs, like this one on dimethylcadmium: | | https://www.science.org/content/blog-post/things-i-won-t-wor... | | "I'm saddened to report that the chemical literature contains | descriptions of dimethylcadmium's smell." | chrisbrandow wrote: | I still remember this event when it happened. I was getting my | PhD at the time. I think about it regularly. | DrAwdeOccarim wrote: | I started my chem grad school about a decade later and all the | changes were well accepted and the field was still mourning her | loss. What a tragedy. | throwawayboise wrote: | I wonder if the outcome would have been differnt if she had | just immediately changed her gloves (or maybe she did? The | story doesn't really say, but implies that she just continued | the experiment). | [deleted] | verisimi wrote: | kwohlfahrt wrote: | Ethylmercury is used insted of (di-)methylmercury, because it | is cleared from the body faster: | https://www.cdc.gov/vaccinesafety/concerns/thimerosal/index.... | bogota wrote: | No its not as you pointed out but didn't clarify. Ethylmercury | is not the same as methylmercury. | hammock wrote: | It is not. The mercury in (some, but not all or even most, | these days) vaccines is ethyl mercury. Here is an article that | explains a bit more of the similarity with dimethyl mercury, | though - they are both organic mercurials: | | >Both ethyl mercury and Hg2+ are very neuro toxic compounds. | However, ethyl mercury is more rapidly partitioned into the | hydrophobic (fatty) tissues of the central nervous system and | is a more potent neuro toxin than Hg2+ based on this | "partitioning factor". It is this partitioning factor that | makes organic mercurials such as dimethyl mercury so neuro | toxically lethal (this is the compound that caused the death of | a Dartmouth University chemistry professor after she was | exposed to a drop or two on her gloved hand). | | >The concern with organic mercurials, such as thimerosal, is | that such compounds can be perceived as "pro toxicants" just as | certain pharmaceuticals can be classified as "pro drugs". This | means that the original compound, e.g. thimerosal, is less | reactive giving the compound time to partition into certain | areas of the body before it breaks down releasing the ethyl | mercury and then further releasing Hg2+. However, while | attaching ethyl mercury to thiolsalicylate makes the ethyl | mercury less reactive it most likely allows increased | partitioning into the central nervous system before the ethyl | mercury is released and thereby, increases the neuro toxicity | per unit ethyl mercury involved | | https://vaccinechoicecanada.com/vaccine-ingredients/thimeros... | bawolff wrote: | I would think it would go without saying vaccines don't use one | of the most toxic substances known by virtue of the fact people | aren't dropping dead. | mahkeiro wrote: | When I was studying chemistry, latex gloves were not allowed in | org chemistry lab as too many thing can go through them and they | provide a false sense of security. | throwawayboise wrote: | I didn't take chemistry past freshman general chem, but we | didn't use gloves at all. Eye protection, yes. | julienchastang wrote: | Note the time between initial exposure and death -- almost a | year. Terrifying. | brazzy wrote: | And about 5 month before any symptoms showed up, then comatose | within 3 weeks. | | I once asked a biochemist how that's even possible. Apparently | it irretrievably destroys a part of the body's metabolism that | is necessary to repair nerve cells. ___________________________________________________________________ (page generated 2022-01-22 23:00 UTC)