Things I Won't Work With: Dimethylcadmium (2013)

https://www.science.org/content/blog-post/things-i-won-t-work-dimethylcadmium

by Bluestein • 2 years ago

301 169 2 years ago

kens• 2 years ago

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.

Bluestein31• 2 years ago

Indeed. In fact, a recent participant around here spoke of dealing with huge amounts of such batteries on a daily, professional basis.-

They were pretty common.-

jaggederest• 2 years ago

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.

Bluestein31• 2 years ago

Stuff's ubiquitous once you start looking.-

dhosek• 2 years ago

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.

timr6• 2 years ago

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.

Dylan168072• 2 years ago

The comment you replied to does not say or imply anything about toxicity.

wisty• 2 years ago

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.

fortran773• 2 years ago

I would guess that kens has a great deal of background knowledge.

hvs• 2 years ago

On the plus side, it's a step up from the general public's: "X is bad because it contains chemicals!"

apothegm• 2 years ago

IIRC the author works in pharmaceuticals. I would be unsurprised to learn that cadmium is rarely used in the production of medications.

fch422• 2 years ago

maybe not Cadmium.

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".

Jeema101• 2 years ago

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.

Tuna-Fish• 2 years ago

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.

teuobk• 2 years ago

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.

supertofu• 2 years ago

A consumer report not too long ago found cadmium at unsafe levels in many dark chocolate brands: https://www.consumerreports.org/health/food-safety/lead-and-...

The cacao was contaminated with cadmium from the soil during harvest.

Bluestein31• 2 years ago

found cadmium at unsafe levels in many dark chocolate brands:

That's just bonkers.-

PS. Lead too, apparently ...

MattGaiser• 2 years ago

Chocolate production is a mess of child labour, toxins, violence, and poverty.

perihelions• 2 years ago

Discussed on HN here (and a few other threads if one's motivated to search):

https://news.ycombinator.com/item?id=38038465 ("A third of chocolate products are high in heavy metals (consumerreports.org)"; 201 comments)

duffpkg• 2 years ago

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.

https://article.images.consumerreports.org/image/upload/v167... https://www.fda.gov/food/environmental-contaminants-food/cad....

Bluestein31• 2 years ago

Lettuce and cereal grains are the most common sources of cadmium in american diets.

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 :)

Waterluvian2• 2 years ago

The amounts we are talking about are extraordinarily small and difficult to measure. We are talking 5-100 quadrillion individual atoms of cadmium.

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.

enraged_camel• 2 years ago

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.

mixmastamyk• 2 years ago

It wasn’t the only study, was it?

gruez• 2 years ago

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?

throw1567542282• 2 years ago

The OP's article says Cadmium is not well absorbed from the gut. So even less reason to be concerned.

Anotheroneagain2• 2 years ago

CC Patterson in fact likely found out that the balance of lead isotopes was impossible, and the "heavy metals" were removed to hide the evidence.

Food will always taste bland to foul without them, we will suffer from "lifestyle" disorders, and nature will keep dying, until they are returned.

fortran773• 2 years ago

Maybe it's the "Cad" in Cadburry?!

Bluestein31• 2 years ago

I for one like your pun.-

PS. Regarding your username, fan of Fortran 75 meself :)

lostlogin3• 2 years ago

I know it varies region to region, but here in New Zealand, Cadbury is probably the worst chocolate you can buy.

nielsbot• 2 years ago

Although, I note (FTA): "Fortunately, cadmium is not well absorbed from the gut,"

So maybe there's hope...

lr4444lr2• 2 years ago

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.)

[0] https://www.consumerlab.com/reviews/flaxseed-whole-ground-an... (may require membership to read).

lazide4• 2 years ago

Probably burned it - hence releasing it all into the air. But hey, out of sight, out of mind?

magicalhippo• 2 years ago

No clue how they would have harvested and disposed of the tainted flax.

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

stephen_g• 2 years ago

They could potentially do pyrolysis of the biomass (after harvest) and then extract the heavy metals from the resulting char.

e.g. https://www.sciencedirect.com/science/article/abs/pii/S09619...

https://www.sciencedirect.com/science/article/abs/pii/S09213...

bregma• 2 years ago

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.

teractiveodular• 2 years ago

(2013)

mhb2• 2 years ago

et alia:

https://hn.algolia.com/?q=things+i+won%27t+work+with+

DylanSp2• 2 years ago

https://www.science.org/topic/blog-category/things-i-wont-wo... links to all of Lowe's posts in this category. The How Not to Do It series is also great - https://www.science.org/topic/blog-category/how-not-to-do-it.

brenns10• 2 years ago

(warning: pedantic comment)

"et alia" is used to refer to "the others (people)" whereas "et cetera" is used to refer to "the others (things)". So you'd use "et cetera" to refer to the other posts. But if you were writing a list of authors you might end with "et al." to indicate that there are more.

I know correcting somebody's Latin usage is really pedantic even by HN's standards. I'm only saying it cause I find it interesting and want to share, not because I want to correct you :)

https://en.m.wikipedia.org/wiki/Et_cetera

Ekaros2• 2 years ago

Are dimethyls with wrong sort of metals all really nasty stuff? Just wondering as dimethylmercury is also nasty stuff.

ta988• 2 years ago

It seem so, but it is a bit more complex in reality

https://pubs.acs.org/doi/10.1021/acs.organomet.7b00605

zdragnar3• 2 years ago

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.

Bluestein31• 2 years ago

A few drops of dimethylmercury on your skin can be fatal.

Sounds like a state actor's weapon of choice ...

User23• 2 years ago

Methylating is like acetylating. It's kind of a go-to thing to try in medicinal chemistry.

monktastic1• 2 years ago

Indeed. I am reminded of the sad and horrible story of https://en.m.wikipedia.org/wiki/Karen_Wetterhahn

culi2• 2 years ago

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

scotteric• 2 years ago

As an aside, methamphetamine is also a prescribed drug in the US, called Desoxyn.

abound• 2 years ago

From the article:

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.

cperciva2• 2 years ago

[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...

stavros• 2 years ago

I'm sure the author knows this, and wants to punch them anyway.

gtmitchell• 2 years ago

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.

thrw9358767• 2 years ago

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.

thaumasiotes• 2 years ago

I was just looking at https://www.ncbi.nlm.nih.gov/books/NBK597858/ , a review of the effects of fluorine in various forms as administered in various ways.

I was pretty surprised to see the experiments on human volunteers.

StableAlkyne• 2 years ago

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

refurb2• 2 years ago

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.

Bluestein31• 2 years ago

("Amd this, dear children is how we got psychedelics ..."

I jest. I believe it was unwanted skin contact ...

amy-petrik-214• 2 years ago

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"

JadeNB• 2 years ago

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.

lifeisstillgood• 2 years ago

>> Cadmium compounds in general have also been confirmed as carcinogenic, should you survive the initial exposure.

I have heard of gallows humour, but its the gallows sarcasm that gets me :-)

fortran773• 2 years ago

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.

rbanffy2• 2 years ago

I can't believe I have to say this, but please don't eat batteries. ;-)

wiml• 2 years ago

It's still reasonably common as an anti-corrosive plating on metal hardware.

tim333• 2 years ago

It sees to make one of the most cost effective solar cells but I think they only use them in commercial projects rather than on roofs.

throw1567542282• 2 years ago

Great discussion following the article in the comments. Bunsen was a legend.

Bluestein31• 2 years ago

I noticed. Also a good read, the entire comment section :)

gizajob• 2 years ago

Nice to see the word “floof” in a Science article

fch422• 2 years ago

I love reading the "things I won't work with" series ... a shame it's no longer being added to.

Just curious: why did Derek Lowe stop writing these ?

mattmaroon• 2 years ago

Perhaps he’ll work with almost everything so he ran out.

Bluestein31• 2 years ago

Wikipedia seems to put 2017 as the stopping point for his collaboration with the publication. He went elsewhere.-

DylanSp2• 2 years ago

He's definitely still blogging on Science, he just hasn't posted any Things I Won't Work With entries in a few years.

petereborn• 2 years ago

I prefer Derek's previous thing he won't work with: Satan's Kimchi. https://www.science.org/content/blog-post/things-i-won-t-wor...

Things I Won't Work With: Dimethylcadmium (2013)

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