[I]ts odor is variously described as "foul", "unpleasant", "metallic", "disagreeable", and (wait for it) "characteristic", which is an adjective that shows up often in the literature with regard to smells, and almost always makes a person want to punch whoever thought it was useful.
No need to punch them; if someone has been exposed to enough dimethylcadmium to describe its odor as "characteristic" they probably don't have long to live...
A generation ago or two ago, it was common for chemists to use taste and smell as a tools for qualitative evaluation of chemical compounds.
So older scientific literature is full of all sorts of knowledge that was obtained in ways that are shockingly unsafe by modern standards, including gems like the taste of all sorts of poisons and how large quantities of plutonium are warm to the touch.
Even as a chemist today you get to recognize the smells of chemicals even if barely exposed.
It's typically only the most toxic that you’d use such equipment to not be exposed at all (but then we tend to avoid those anyways).
You start to recognize the smell of ethers like diethyl ether or tetrahydrofuran (which I love the smell of). Sulfides are obvious (smell terrible).
I made a mistake a couple times smelling things I shouldn’t.
Once was diazomethane gas - a potent akylating agent and explosive. I instinctively put the roundbottom flask to my nose to smell, but realized after how dumb it was. No idea if i heavily alkylated my nasal passage epithelial cells or not, but no side effects.
The other time was a brominated aryl compound similar to tear gas. That was amazingly painful and felt like getting wasabi up my nose despite there being almost nothing left in the flask.
One time which wasn't intention was smelling CbzCl (benzyl chloroformate, a reagent used to add a protecting group to nitrogens). I didn't intentionall smell it, but measured it outside the fume hood in a syringe. It smells pretty awful, but what I realize is that the molecule must bind to your nasal passages (proteins have lots of nitrogens) because I could smell it for the next 24 hours. After smelling it that long, the smell now makes me nauseous pretty quickly.
> older scientific literature is full of all sorts of knowledge that was obtained in ways that are shockingly unsafe by modern standards
My favorite is there are old manuals that recommend smoking while working with cyanide. Allegedly it produces a very disagreeable flavor when you inhale the cyanide through the cigarette, so you get warning to get out of the area*
This was before fume hoods were common, when you would most likely be doing this outside or next to a window
* I have not tested this, and I don't know of anyone who has, so don't rely on what could be an old telephone game for chemical safety
A friend’s dad recognised cyanide during a chemistry exam by tasting it. (He survived and passed the exam.)
The task was to say what each of n substances given were in a short enough amount of time, filling out a report. I’m not sure if they still give cyanide to students during exams. That was communist Poland.
on this point, the disease "diabetes" comes from an old latin word "diabeetus" which is Spanish for "urine which tastes very sweet with a hint of cinnamon". Now.. .. one can imagine how physicians of the time would go about diagnosing this disease, "diabeetus"
The author says just that in the previous sentences:
> I'm saddened to report that the chemical literature contains descriptions of dimethylcadmium's smell. Whoever provided these reports was surely exposed to far more of the vapor than common sense would allow, because common sense would tell you to stay about a half mile upwind at all times.
In short the article and conclusions are a total mess and made a nice attention grabbing headline with little to no substance.
As someone that has built and managed clinical laboratories for human samples, I find this article from consumer reports extremely misleading. The describe results as a percentage of a theoretically acceptable level. For example, for cadmium, they are saying an acceptable level is 4.1 ug/day . Then they seem to imply that "TJ The Dark Chocolate Lover's Chocolate 85% Cacao" has 229% of the 4.1ug/day if a consumer ate a 30g piece.
They never actually spell out what they mean or what the actual results they found were, or what the limit of detection of the methodology was or the error range of their tests. I guess they are saying that that chocolate has 9.3ug of cadmium in a 30g sample but it's impossible to say from what they wrote.
The FDA states that the maximum daily consumption of cadmium should be limited to 0.21-0.36ug per kg of body mass. For an avg american male that would mean a threshold of 17.64-30.24ug/day. A typical salad containing 250g of romaine lettuce has 2-14ug of cadmium in it. Lettuce and cereal grains are the most common sources of cadmium in american diets.
The amounts we are talking about are extraordinarily small and difficult to measure. We are talking 5-100 quadrillion individual atoms of cadmium.
>The amounts we are talking about are extraordinarily small and difficult to measure. We are talking 5-100 quadrillion individual atoms of cadmium.
In short you're saying that the CR numbers are suspicious because they're near the limits of what labs can detect? Is there some source you can provide for this?
You're asking people here to put their faith in a comment by some rando (i.e. you) over a well-reputed publication that millions of people have been relying on for decades. I think most will balk at the idea, and I'm one of them. No offense.
Flaxseeds as well. ConsumerLabs carefully documents the cadmium concentration of common brands[0], and many are unsafe.
Flax is such an efficient bio-concentrator of cadmium in fact, that a municipality in PA considered sowing a field of it to remediate a polluted former industrial site. (No clue how they would have harvested and disposed of the tainted flax.)
> No clue how they would have harvested and disposed of the tainted flax.
It's flax. Harvest it before it goes to seed, ret it, break it, scutch it, spin it, weave it, make it into expensive garments. Unless you eat your shirt it's going to be perfectly safe.
Cadmium used to be all around us in Nickel-Cadmium batteries, and in Cadmium Sulfide "electric eye" photoresistors, that lower their resistance when exposed to light, and increase their resistance in darkness. (https://en.wikipedia.org/wiki/Photoresistor).
Its probably a good idea to avoid drilling, sanding, or filing things that may have Cadmium in them if you're dismantaling old electronics, lets you inhale it.
Methyl groups play heavily in organic chemistry. As an organic compound, it allows otherwise fairly inert metals to be easily absorbed into body tissues and interfere with the chemical processes therein.
To take mercury for example, you can stick your hand in a vat of elemental mercury and be fine. A few drops of dimethylmercury on your skin can be fatal.
Yeah I find this interesting too. A methyl group separates the street drug meth from the prescribed drug amphetamine. The main role that methyl group plays is the way it crosses the blood brain barrier. During the process of crossing the methyl group is lost. Which means with both meth and regular amphetamine the chemical that reaches your brain is the same.
I wonder if the dimethyl plays the same role here. Allowing it to cross the blood brain barrier faster
An entertaining article. It's strange to see cadmium described as something obscure that hardly anyone encounters. NiCad batteries were pretty common as well as CdS photo resistors for anyone doing electronics.
Again, the usual "hacker news learns about chemistry" disclaimer must be specified: just because a chemical shares a part of another chemical does not mean that it shares the toxicity of that other chemical.
Chemistry is complex. Biology, even more so. You can't just say "oh, it contains cadmium", and assume that it's bad.
With heavy metals like Cd, it's a good first order of approximation. It's not like flourine that's a vicious oxidiser when it's alone, and so stable the only real issue with it is you can't get rid of it when it's with friends.
Also just about every yellow or orange pigment, like in e.g. oil paint, is cadmium selenide or something in that family, as far as I am aware. Same for ceramics, if you want a nice yellow or orange it's cadmium time.
I remember seeing a cadmium spill on the edges of the sewage treatment plant near where I grew up. I was a nerdy enough kid to recognize it when I saw it.
As an interesting aside, right now bright OLED screens have pretty bad wear characteristics. We do have a cheap solution that would work, but it requires cadmium.
A decade ago or so there was an application for RoHS exemption for the use of cadmium in displays, and their argument was that because coal plants emit cadmium, and because Oled screens with cadmium quantum dots are so much more efficient than backlit screens, that in practice allowing the use of cadmium in screens would reduce total cadmium release into the environment. It didn't pass.
Cadmium was also widely used in the past as a galvanic coating on iron and steel parts to keep them from rusting. And unfortunately when and if it oxidizes, it can become powdery and easily airborne. I mess around with old electronics and it's unfortunately pretty common to encounter on old metal radio chassis and things like that.
Still quite common to encounter elemental cadmium in other contexts, too. I'm around it all the time while working on my race cars where (at least in amateur circuit racing in North America), the use of cadmium-plated "AN" and "MS" fasteners is extremely common. Ditto for aviation.
Mercury is, though, https://en.m.wikipedia.org/wiki/Merbromin - and on the "paints & coatings" side, orange-red and anti-rust often enough used mercury salts as well. Rarely these days, fortunately.
In some ways, it's nice GaN "won" for blue LEDs. CdTe / CdSe would literally have been "twice bad".
Readit News
No need to punch them; if someone has been exposed to enough dimethylcadmium to describe its odor as "characteristic" they probably don't have long to live...
So older scientific literature is full of all sorts of knowledge that was obtained in ways that are shockingly unsafe by modern standards, including gems like the taste of all sorts of poisons and how large quantities of plutonium are warm to the touch.
It's typically only the most toxic that you’d use such equipment to not be exposed at all (but then we tend to avoid those anyways).
You start to recognize the smell of ethers like diethyl ether or tetrahydrofuran (which I love the smell of). Sulfides are obvious (smell terrible).
I made a mistake a couple times smelling things I shouldn’t.
Once was diazomethane gas - a potent akylating agent and explosive. I instinctively put the roundbottom flask to my nose to smell, but realized after how dumb it was. No idea if i heavily alkylated my nasal passage epithelial cells or not, but no side effects.
The other time was a brominated aryl compound similar to tear gas. That was amazingly painful and felt like getting wasabi up my nose despite there being almost nothing left in the flask.
One time which wasn't intention was smelling CbzCl (benzyl chloroformate, a reagent used to add a protecting group to nitrogens). I didn't intentionall smell it, but measured it outside the fume hood in a syringe. It smells pretty awful, but what I realize is that the molecule must bind to your nasal passages (proteins have lots of nitrogens) because I could smell it for the next 24 hours. After smelling it that long, the smell now makes me nauseous pretty quickly.
My favorite is there are old manuals that recommend smoking while working with cyanide. Allegedly it produces a very disagreeable flavor when you inhale the cyanide through the cigarette, so you get warning to get out of the area*
This was before fume hoods were common, when you would most likely be doing this outside or next to a window
* I have not tested this, and I don't know of anyone who has, so don't rely on what could be an old telephone game for chemical safety
I was pretty surprised to see the experiments on human volunteers.
The task was to say what each of n substances given were in a short enough amount of time, filling out a report. I’m not sure if they still give cyanide to students during exams. That was communist Poland.
Deleted Comment
I jest. I believe it was unwanted skin contact ...
> I'm saddened to report that the chemical literature contains descriptions of dimethylcadmium's smell. Whoever provided these reports was surely exposed to far more of the vapor than common sense would allow, because common sense would tell you to stay about a half mile upwind at all times.
The cacao was contaminated with cadmium from the soil during harvest.
As someone that has built and managed clinical laboratories for human samples, I find this article from consumer reports extremely misleading. The describe results as a percentage of a theoretically acceptable level. For example, for cadmium, they are saying an acceptable level is 4.1 ug/day . Then they seem to imply that "TJ The Dark Chocolate Lover's Chocolate 85% Cacao" has 229% of the 4.1ug/day if a consumer ate a 30g piece.
They never actually spell out what they mean or what the actual results they found were, or what the limit of detection of the methodology was or the error range of their tests. I guess they are saying that that chocolate has 9.3ug of cadmium in a 30g sample but it's impossible to say from what they wrote.
The FDA states that the maximum daily consumption of cadmium should be limited to 0.21-0.36ug per kg of body mass. For an avg american male that would mean a threshold of 17.64-30.24ug/day. A typical salad containing 250g of romaine lettuce has 2-14ug of cadmium in it. Lettuce and cereal grains are the most common sources of cadmium in american diets.
The amounts we are talking about are extraordinarily small and difficult to measure. We are talking 5-100 quadrillion individual atoms of cadmium.
https://article.images.consumerreports.org/image/upload/v167...https://www.fda.gov/food/environmental-contaminants-food/cad....
I get what you’re saying but I think it’s kind of funny how impossible it is for a layperson to have any clue if that number is a lot or a little.
Lettuce has cadmium. TIL.-
> threshold of 17.64-30.24ug/day.
So; it I am not mistaken; by these measurements the amount claimed to be contained in the article, for chocolate; would be within bounds ...
(It's just you then could not go ahead and have a salad :)
In short you're saying that the CR numbers are suspicious because they're near the limits of what labs can detect? Is there some source you can provide for this?
Food will always taste bland to foul without them, we will suffer from "lifestyle" disorders, and nature will keep dying, until they are returned.
Flax is such an efficient bio-concentrator of cadmium in fact, that a municipality in PA considered sowing a field of it to remediate a polluted former industrial site. (No clue how they would have harvested and disposed of the tainted flax.)
[0] https://www.consumerlab.com/reviews/flaxseed-whole-ground-an... (may require membership to read).
e.g. https://www.sciencedirect.com/science/article/abs/pii/S09619...
https://www.sciencedirect.com/science/article/abs/pii/S09213...
Sounds like a good basis for a NileRed[1] episode, say making paint[2] from flax seeds.
[1]: https://nile.red/
[2]: https://en.wikipedia.org/wiki/Red_pigments#Cadmium_red
It's flax. Harvest it before it goes to seed, ret it, break it, scutch it, spin it, weave it, make it into expensive garments. Unless you eat your shirt it's going to be perfectly safe.
https://news.ycombinator.com/item?id=38038465 ("A third of chocolate products are high in heavy metals (consumerreports.org)"; 201 comments)
PS. Regarding your username, fan of Fortran 75 meself :)
So maybe there's hope...
That's just bonkers.-
PS. Lead too, apparently ...
I have heard of gallows humour, but its the gallows sarcasm that gets me :-)
Its probably a good idea to avoid drilling, sanding, or filing things that may have Cadmium in them if you're dismantaling old electronics, lets you inhale it.
To take mercury for example, you can stick your hand in a vat of elemental mercury and be fine. A few drops of dimethylmercury on your skin can be fatal.
Sounds like a state actor's weapon of choice ...
https://pubs.acs.org/doi/10.1021/acs.organomet.7b00605
> The general rule is, if you're looking for the worst organic derivatives of any metal, you should hop right on down to the methyl compounds.
I wonder if the dimethyl plays the same role here. Allowing it to cross the blood brain barrier faster
Chemistry is complex. Biology, even more so. You can't just say "oh, it contains cadmium", and assume that it's bad.
Deleted Comment
A decade ago or so there was an application for RoHS exemption for the use of cadmium in displays, and their argument was that because coal plants emit cadmium, and because Oled screens with cadmium quantum dots are so much more efficient than backlit screens, that in practice allowing the use of cadmium in screens would reduce total cadmium release into the environment. It didn't pass.
Mercury is, though, https://en.m.wikipedia.org/wiki/Merbromin - and on the "paints & coatings" side, orange-red and anti-rust often enough used mercury salts as well. Rarely these days, fortunately.
In some ways, it's nice GaN "won" for blue LEDs. CdTe / CdSe would literally have been "twice bad".
They were pretty common.-
Just curious: why did Derek Lowe stop writing these ?