I just got an image-use request from the rather interesting NowPublic news site. They wanted to use one of my pictures of my 85-watt compact fluorescent to illustrate this article, about the dangers of mercury exposure from broken compact fluorescent lamps.
As regular readers would expect, I said no, and started in on an interminable explanation of why. It got long enough that I turned it into this blog post.
Executive summary: The second you read someone saying that metallic mercury is an incredibly potent neurotoxin, you know you're looking at bullshit.
ORGANIC mercury compounds are indeed ultra-poisonous, but metallic mercury quite simply is not. It ain't good for you; there ain't no Vitamin C in there. But breathing a bit of metallic mercury vapour really is not a big deal.
And the amount of metallic mercury in a domestic CFL is tiny - only a few milligrams. And it's all likely to be in the vapour state. So if you break the bulb anywhere with remotely normal indoor ventilation levels, the vapour will just blow away, in minutes at most. You'd have to smash the bulb and immediately stick your nose into the shards and inhale to get any measurable mercury dose at all.
If there were epidemiological support for the idea then the lack of a plausible mechanism of action wouldn't matter so much, but there isn't, especially after you filter out the unsourced ravings of people who're sure that tiny mercury doses from fillings or vaccinations cause every disease under the sun.
(Fools! Don't they know it's really aspartame we should be worrying about?!)
The NowPublic piece does have a source for the idea that tiny non-chronic metallic mercury exposure is bad for humans; it's the "study of workers" mentioned at the top of the article.
That study is not, by the way, the same as the "Maine scientific study" the article mentions next, which in fact concluded that existing cleanup methods were OK.
The "study of workers" is quoted hither and yon, but usually, as in this case, without a footnote saying where and when it was actually published.
It was published in the journal "Environmental Research" in 1993; here's the abstract. The study was done by the Department of Occupational Health at Shanghai Medical University, and it concluded that exposure to 33,000 nanograms of mercury per cubic metre of air seemed to have a measurable effect on people's mental abilities, with only a very small chance that this difference was a mere fluke.
But the average duration of exposure in the Shanghai study was TEN-POINT-FOUR YEARS.
The Maine study, I remind you, considered a "short excursion" of mercury concentration above 25,000 nanograms per cubic metre, as a result of a broken CFL, to be large. It found contamination briefly reaching more than 100,000 nanograms per cubic metre was "possible", but presumably didn't actually manage to measure it, on account of the very brief duration of such contamination as the trace of mercury vapour swirled away.
Mercury vapour exposure times from a broken CFL are likely to be measured in minutes, at most. There just isn't enough mercury in a domestic fluorescent lamp to keep a significant volume of air at the Shanghai study's dosage - far above the 300ng/m^3 Maine Ambient Air Guideline - for more than a few minutes.
I mean, even if you've got five milligrams of mercury in your CFL - you probably don't, but let's say you do - then that's five million nanograms, so it can contaminate 151.5 cubic metres of air to 33,000 ng/m3. Open a window or two and a lot more air than that is likely to blow through the room in an hour (the heavy mercury vapour can also just leak out through the floorboards of a "sealed" room). I cannot imagine how someone in a normal domestic or commercial setting could manage to keep the contamination level of a room in the tens of thousands of nanograms per cubic metre level for more than a few minutes, if they've only got a few milligrams of mercury vapour to do it with.
Given that there are more than half a million minutes in a year, I think it's clear that the exposure times in the Shanghai and Maine studies are not even remotely comparable. The NowPublic article puts the results of these two studies right next to each other as if they're both talking about the same thing, and doesn't even tell readers where to find information about the studies so they can discover the imposture.
And, on top of that, the Environmental Research study was just that one study, done by Shanghai Medical University fifteen years ago. There've been many other studies of chronic low-level mercury exposure, and it's easy to find ones that conclude that it has little to no effect, even after many years. And, I repeat, years of exposure comprise hundred of thousands, and quite possibly millions, of times the mercury exposure you can get by breaking a CFL.
So right now, there does not appear to be any reason to be particularly concerned about breaking even large fluorescent tubes indoors, let alone little CFLs. And the Maine study in fact supports this conclusion, because it found that breaking CFLs cannot create the chronic exposure which the subjects of the Shanghai study had suffered.
So it would appear that the mysterious CFL Bandit is not, in fact, a menace to public safety.
4 September 2008 at 7:22 pm
Ah, the usual "dangers of everyday materials to the consumer" articles. These things are pretty much everywhere and around half of them are absolute bullshit or overblown facts based on irresponsible and downright bad research.
5 September 2008 at 6:38 am
What about the folk medicine cure used for stomach troubles in some Latin American countries, which is to drink liquid Mercury (Wouldn't want to stand behind one of those people if they broke wind!). Also, what about things such as Mecurochrome? I can remember that being used on me as a child. Plus, there were many other "medications" containing much more Mercury than a CFL contains (even a case of CFLs), and humanity seems to have survived.
Dave
5 September 2008 at 7:45 am
A swig of mercury was apparently a pretty popular treatment for a lot of things, back in the days when bloodletting and cupping were considered an important part of balancing your humours.
5 September 2008 at 8:46 am
To be fair, Dan, if one was employed as a Compact Fluorescent Light Bulb Shatterer, there might actually be some health problems?
Really, though, thanks for exposing yet another Bunch Of Crap.
5 September 2008 at 8:52 am
Well, Dave, there's always this...
5 September 2008 at 10:10 am
Dan, did NowPublic respond to your criticisms of their shoddy journalism?
[No, but they're not one monolithic journalistic entity; they're a site where anybody can write a story, then other people can express their opinions about it. It's not a wiki system, though; you can't EDIT other people's stories. So it's sort of like the Everything2 or Metafilter of news. -Dan]
5 September 2008 at 10:22 am
Is metallic mercury the one usually used in industry? I ask because a friend brought a bottle of mercury to school which he acquired from his fathers shed who did some industrial work. he had very large plastic bottles of the stuff for some reason. We, of course, played with it with wild abandon. (holding in hands, pushing around the place etc) This was all done outside and we lost pretty much all of it on the ground in between the pavers.
Could this have done any long term harm to any of us if it was metallic mercury? Looking at your previous articles on the subject I'm not too worried, and about 7 years on none of has have died or had any sort of serious health issues.
5 September 2008 at 10:51 am
I remember braking thermometers and keeping the mercury from those in a matchbox to play with. This was a fairly common thing to do in Poland in the 70's and early 80's. Am I doomed?
5 September 2008 at 12:14 pm
I actually remember hearing the scare stories about CFLs growing up. Not knowing any better at the time, I was always very cautious around loose bulbs. But, after getting learned some chemistry, the whole thing seemed really stupid. There's plenty of other chemicals in the average house that can do you harm, worrying about trace mercury amounts seems like such a waste of time.
5 September 2008 at 2:26 pm
Re: the Mercurochome business: I've heard of that too, but the amount of elemental Mercury in a bottle is tiny; the FDA actually responded to an URBAN LEGEND that stated that supposedly burn patients were being slathered in the stuff and receiving unhealthy doses of Mercury. Not only is this not correct protocol for burns (they use some kind of silver compound I think; oddly enough another elemental metal...) but it's complete horseshit.
5 September 2008 at 2:32 pm
In answer to the two "am I doomed" questions:
Yes. You are going to die.
But so's everybody else, so I wouldn't get too bothered about it.
Acute metallic mercury exposure in the classic pushing-it-around-in-the-palm-of-your-hand way is indeed bad, but I think metallic mercury really doesn't bioaccumulate in humans all that well. You can't actually absorb it very effectively through your skin or even through your gastrointestinal tract, and you'll wee and sweat out a significant amount of what mercury does make it in. I remember reading an old National Geographic that mentioned the saunas used to treat people with severe metallic-mercury exposure; little droplets of mercury metal could indeed actually be recovered from their sweat!
If you're not going back to the vat of mercury every day to make more hat-felt, then even if you did eat some of the stuff, it won't necessarily have any quantifiable health impact on you. Chronic occupational exposure at even low levels is a different story, as are organic mercury compounds, but handling the metal itself on a few occasions does not appear to any more dangerous than occasionally getting a whiff of the tin-and-lead solder you're using to build an electronics kit.
6 September 2008 at 1:50 am
I thought every kid played with metallic Mercury in elementary school! I know I did. Some kid brought a pound bottle of it to my sixth grade class, and we had lots of fun pouring it out on the desks, squishing it (with our bare hands!), letting it fall on the floor and shatter (or stomping on it with our feet), and then rolling the little beads back together and repeating the process. Hmm, that's been about 40 years ago, but the school is still in use. I wonder if it's been "decontaminated" yet? ;-)
While I was going to engineering school, I eventually received an office to use. Upon opening the top draw of the desk in that office, my first thought was "Gee, someone left an assortment of ball bearings in this drawer.". Then, after examining the "ball bearings" a bit closer, my reaction was "Noooo, that's Mercury!". So, I scraped it up (using my fingers) into an envelope, and ended up with between a quarter and a half of a pound of it. I then took it up to the chemistry department and donated it to one of the chemistry profs, who was thrilled to get it (since the price of Mercury had recently shot up, and they went through the stuff like crazy). Oh, and I got a really good grade out of his chemistry class, too. And, I continued to use that office, too. ;-)
But, despite those, and other, exposures, I haven't noticed
any 143=-DFaspert1i34uty-1jh-380j side-effects. ;-)
Dave
6 September 2008 at 9:33 am
What about taking fluorescent bulbs to a special recycling place? Here in the Seattle area, when you buy a new energy-saving fluorescent bulb, there's a web site printed on the side of the box where you're supposed to go and take the used bulb so that it doesn't destroy the planet.
Not much mercury in one bulb, but it seems like if there were a LOT of bulbs (say a million households or so), it could add up to a significant amount.
Or are we just making ourselves feel better (and burning gas to drive to the recycling places on the way)?
6 September 2008 at 11:54 am
I remember seeing something quite recently on The New Inventors - though it could have been a repeat - about a man who'd invented a fluoro bulb recycler that can be retrofitted to a wheelie bin. It had all kinds of awesome vacuumy bits and carbon filters and the like to protect us from chemical nasties.
Are you saying that it's really no big deal?
6 September 2008 at 12:57 pm
Recycling sites and/or garbage dumps where lots of fluorescent lamps end up - including the much bigger tubes that used to be the ONLY kind of domestic fluorescent - certainly could end up with significant mercury contamination. I still wouldn't be bothered about going there to drop off my own lamps, but working in the area could easily give you a significant cumulative mercury dose, especially if the tubes are all sitting there in the open getting rained on and reacting with whatever other junk and bacteria happen to be there, which could result in significant amounts of organic mercury compounds.
Working in such a place is still not like being given an office in Chernobyl Reactor Building Four, but I'd want to know that my employers got a bloke with a sniffer meter to wander around the place once a year and complied with all other relevant legislation. This is good practice in any dump anyway; you never know when someone's going to sneak in there with a bunch of rusty barrels from the Too Expensive To Dispose Of Properly room at the local university.
Regarding special on-site disposal devices: They may be very handy if your aim is to keep your workplace below some very low Precautionary-Principle mercury-contamination level, but those very low permissible levels are probably for chronic exposure, not the brief exposure that happens if you happen to be working on the loading dock when someone comes by and tosses four six-foot fluoros into the open-topped skip.
It's possible that enforcement of the lower limit may be done by someone who hasn't read that far in the guidelines, though, or by some bloody-minded local-council jobsworth who just refuses to understand what he's actually meant to be doing.
That aside, unless you literally are in the fluorescent-light wrecking business, I can see no practical reason for an ordinary business to have a special filtered-ventilation fluoro-disposal bin.
11 September 2008 at 11:02 am
Dan, any idea where to find some 85w bayonet CFLs? The links from your 2006 article no longer work and my Googlefu has turned up nothing usefull.
24 December 2008 at 1:43 am
I just broke one of those light bulbs. Am bringing it to a site and dumping the lamps. I can just see New Yorkers using these light bulbs. No way.
24 December 2008 at 3:39 am
Um... what?
8 February 2009 at 8:03 am
mercury in a hot lamp is gaseous so you stand a good chance of getting a lung full if you break one that is lit. In a cold lamp the mercury is condensed out all through the lamp envelope so less chance of getting too much until you get the dust up in the air this is why it is inadvisable to use a vacuum cleaner to clean them up.
Real problems occur in landfill when the microbes present convert the mercury to methyl mercury that is water soluable and 20 times more poisonous to higher life form than metallic mercury.
So don't break them and do recycle them if you csn suffer them in the first place!
By the way according to research carried out for the European parliament it takes 12 times the energy to manufacture a compact fluorescent energy saver lamp that it does to manufacture an incandescent lamp. The study also shows that only 5 grams of waste are produced during the manufacture of an incandescent lamp whereas 112 grams of waste of which 78 grams are hazardous are produced in the manufacture of a compact fluorescent that typically weighs 80 grams!
Kevan Shaw Direstor of Sustainability for the Professional Lighting Designers Association
8 February 2009 at 12:19 pm
Do you have a source for any of this, Kevan?
The only documents I can find say that environmental mercury is significantly reduced by the use of CFLs, because lower power consumed means less coal burned. I've also never heard these claims about manufacturing energy and waste. Obviously a CFL is a more complex object than an incandescent globe, but I find it hard to believe that the difference outweighs the fourfold power-consumption difference, especially given that CFLs can last a lot longer than incandescents.
8 February 2009 at 12:53 pm
On reading a bit more, it becomes clear that Kevan's Professional Lighting Designer's Association has an official position on the topic of banning incandescent bulbs altogether, namely that it's a dumb idea. I concur, here; things like cupboard and bathroom lights that aren't left on for long periods and are turned on and off frequently should stay as incandescents, at least until we can come up with a CFL that doesn't die after X many power cycles, X being too few for the lamp to last in one of these situations.
[EDIT: It now occurs to me that LED lamps will be a good option for almost all of these situations. They're still not quite cheap and bright enough for use as a bathroom light, even when you consider the fact that they'll probably last pretty much forever. But super-LEDs are already quite able to substitute for the low-wattage bulbs that illuminate the insides of fridges and microwaves. You probably can't yet buy an LED lamp with the right dimensions and base to fit in those little nooks, but as soon as even a half-hearted "incandescent ban" is legislated somewhere big, Chinese factories will start pumping out LED fridge bulbs.]
I doubt, however, that incandescent-bulb bans will be so thorough that it will actually be impossible to buy bulbs for these purposes. Perhaps the EU one really will be; I don't know.
The foundations of the PLDA's complaint seem to me to be a scattershot collection of factoids, not all of which are true. Among the statements which I think are invalid:
* CFLs are unsuitable for use on dimmer-switch circuits. This is true for common-or-garden CFLs; if you've got the usual kind of little-buzzing-knob dimmer, you have to remove it altogether from the circuit, not just leave it turned up to max. But it is now possible to buy dimmable CFLs, reducing this problem to a minor nuisance.
* "The ballast power factor is very poor." It's my understanding that it's now quite difficult to buy a CFL with a lousy power factor; power-factor correction circuitry is standard equipment for modern CFLs. I suppose the PLDA ought to know more about this than I do, but they don't seem to mention corrected CFLs at all, which strikes me as odd.
* No organised way to recover or recycle the lamps. True, but not very relevant. I think it's not a bad deal to get a little metallic mercury going into landfills in return for not burning a lot of coal, which creates several different flavours of air pollution, and of course lots of CO2. If you prefer the air-pollution option, put your old CFLs in a bucket, take it outside, and smash 'em with a brick; the mercury will all have wafted away in a minute or two, and you can drop the remains in the bin.
* Disturbance of sleeping patterns, zero effect on real carbon emissions because of carbon-trading systems that already exist: Now I think you're just being silly.
People with CFL bedside lamps are not all suddenly being stricken with insomnia, and I think your understanding of cap-and-trade systems is defective. Yes, organisations subject to emissions-trading systems like the EU one are, in the aggregate, still going to emit as much as the system allows them to, but the whole point of these systems is to reduce pollution by slowly reducing the cap, and it won't be possible to do that if nobody saves any bloody power. The more CFLs and other emissions-reducing devices people install, the lower will be the industry pressure to keep the cap high.
(And you can too use CFLs in enclosed outdoor light fittings. I do here. They may never warm up and start glowing properly if you're using them in a winter in most of the EU, but in warmer climates - including some of the EU - they work just fine.)
6 April 2009 at 11:08 pm
Daniel, I just got back here an fel I should answer some of your points.
1 PLDA is not my organisation I am a member. It is composed of a large number of Independent lighting Designers throughout the world. I am a mere voluntary Director!
2 Since writing the EU ban has been passed as EU law. Incandescent lamps will now disappear completely over the next few years.
3 We have a number of "Dimmable CFLi" None perform as well as incandescent lamps. Many have a limited dimming range and start to flicker badly below 30%. None look good dimmed the colour appearance goes gray rather than warmwer lik an incandescent. Retail price for "Dimmable lamps is betwen 5 and 10 times that of a conventional CFLi and few retail places stock them.
4 Power factor very relevant! MOST CFLi are por power factor, Yes good power factor lamps can b made but in the EU are not generally available as again they are more costly than poor power factor types. The EU regulations set in place PERMIT poor power factor lamps so there is no market for more costly corrected lamps.
• The mercury figures used in these comparisons are worst case. In the EU less than 30% of electricity is generated by coal fired power stations. Mercury scrubbing of flue gas is very easy and should be installed as standard farily soon. CFLi will acount for 1.7 tonnes of metallic mercury in landfill in the EU each year once Incandescents are completely phased out. The problem is conversion to highly toxic Methyl Mercury in landfill, this is a one way route to the food chain and is fast. Airbourne mercury does not all end up in the food chain.
5 Sleep disturbance, may not affect everybody but is shown as evidentially proven. It is more likely to affect people with other problems such as Dementia, Asberger's syndrome, Epilepsy etc.
6 We are concerned that we are trading power generation emissions for other more insidious problems. The high proportion of non recoverable plastics, mercury , non re-useable glass that come from the manufacture of CFLi are contributing to the depletion of many natural resources. Workers are being unnecesserily exposed to hazardous materials and processes.
There are now a number of efficient Tungsten Halogen incandescent lamps appearing in the market. They offer at least 30% direct energy saving with none of the risks associated with CFLI however the EU legislation will ban these as well!
Kevan Shaw
7 April 2009 at 5:25 pm
I'm still waiting for you to source these statements, Kevan. I'm sure that at least some of what you say is true, but I really do need to know on what you base your assertions, because they do not seem to entirely match up with what I know about these subjects.
The EU incandescent-lamp ban, to choose one example, does indeed have a 2012 deadline. But member states are left to their own devices as to how they enforce this. Some are banning sales of incandescent lamps altogether; others, like Britain, have a voluntary phase-out, starting with hundred-watt bulbs.
I need to know why you think the ban will, in fact, make it impossible to buy incandescent bulbs of all sorts in all - or even most - of the EU by 2012. Given the usual degree to which nations conform to international agreements - even ones having to do with very important things like human rights and inhumane weapons, never mind just light bulbs - I'd find it very surprising if incandescent bulbs actually became impossible to at least buy in batches on eBay from overseas, even in countries that ban their sale locally.
I also expect to see exceptions made, in at least some nations, for specialty bulbs that cannot be had in more efficient versions, and whose contribution to the overall energy budget is not large. Take purpose-built heat lamps, for instance. (Apparently it actually is possible to buy compact fluorescents that fit in standard 375W heat-lamp sockets - this of course means your bathroom heater doesn't heat any more. :-)
And even if it really does become impossible, or unreasonably impractical, to buy ordinary incandescent bulbs in many nations, a deadline of 2012 strikes me as one that gives a decent amount of time for usefully bright and affordable (especially when you take into account their very long lifespan) LED lamps to arrive.
So I just don't see what the big problem is, Kevan. Please support your argument with references if you choose to continue.
10 May 2009 at 2:03 am
Your words: "Executive summary: The second you read someone saying that metallic mercury is an incredibly potent neurotoxin, you know you’re looking at bullshit. ORGANIC mercury compounds are indeed ultra-poisonous, but metallic mercury quite simply is not. It ain’t good for you; there ain’t no Vitamin C in there. But breathing a bit of metallic mercury vapour really is not a big deal."
The words of people who actually know:
"There is no comparable body of epidemiological
evidence on the effects of mercury
vapor in the very young, but an analogous
hypersensitivity of the developing brain to
damage from elemental mercury has been
well documented in animal studies."
• Edward Groth, PhD, Groth Consulting Services, Pelham, NY
• Alicia Culver, Green Purchasing Institute and
• Eric Uram, Headwater Consulting / Sierra Club – National Environmental
Quality Strategy Team.
Mercury Policy Project
1420 North St.
Montpelier, VT 05602
http://www.mercurypolicy.org
©2008
Now, your job is to admit your ignorance and advise your readers.
10 May 2009 at 3:14 am
It took me a while to find the document you're quoting there, wkmacc, since you didn't mention the title.
(This, of course, immediately made me think that you, or someone upstream from you, had just made the whole thing up, because that's what usually happens when people throw around unsourced quotes. Only my preternatural desire to not do anything productive or entertaining with what remains of my evening spurred me to continue the investigation.)
The document in question is titled "Shedding Light on Mercury Risks from CFL Breakage", and it can indeed be found on a Mercury Policy Project site of some description - mpp.cclearn.org, instead of their main http://www.mercurypolicy.org . Interested readers can download it from here (PDF).
Unfortunately, although the authors certainly do say that "hypersensitivity of the developing brain to damage from elemental mercury has been well documented in animal studies", they do not cite any such studies. It's also a bit odd that there's no human epidemiological evidence to be had - if this is actually the case - since quite a lot of epidemiological studies have been done on people who live in areas with lots of air pollution, and air pollution from coal-fired power stations, among other sources, is rich in elemental mercury.
And the Mercury Policy Project themselves don't seem to make this same claim anywhere else, which also strikes me as odd.
I can't, for a start, find it anywhere on the main Mercury Policy Project Web site. When I searched the site for "developing brain", I found they have a document called "Over the Limit: Eating Too Much High-Mercury Fish", dated October 2008 and authored by Edward Groth and Eric Uram, here (PDF). It's about methylmercury, which you'll recall I agree is a very toxic substance, but it doesn't seem to mention elemental mercury anywhere. If they think elemental mercury's a big deal, you'd think they'd have mentioned it.
The only other mercurypolicy.org hit for "developing brain" was a link on this page, to a paper (PDF) titled "Public Health and Economic Consequences of Methyl Mercury Toxicity to the Developing Brain". Which, again, ain't about metallic mercury; they mention metallic mercury, but only because elemental mercury pollution that finds its way to the appropriate bacteria can be turned into methylmercury. Which, once again, is bad news.
Switching the search to mpp.cclearn.org, I found the CFL-breakage document, two more documents warning about methylmercury, and two documents that mention the possible dangers of mercury fillings. Read charitably, they recommend the application of the precautionary principle, which in this case apparently means avoiding mercury-amalgam fillings that provably outgas very very close to zero mercury - well, compared with the amount of mercury you inhale every day from normal suburban air, anyway. Instead, I suppose you should insist on gold, no matter how expensive it is, because I'm sure nobody this dedicated to the precautionary principle would recommend those strange and untested composite fillings composed of synthetic resins with names as long as your arm.
The authors you mention also don't seem to have any collaborative works listed in Medline. I'm no Medline search ninja, but I've done a few searches now and haven't found anything from anybody else that supports your statement, either. I mean, apparently you can probably tell, by dissecting fetuses, if pregnant rats were exposed to four hours a day of air contaminated with 300 micrograms of metallic mercury per cubic metre; since that's one thousand times the Maine Ambient Air Guideline of 300 nanograms per cubic metre, I'm not bloody surprised.
It's not hard to find hits for a search vaguely connected with with developing brains and mercury hypersensitivity; here's a jumping-off point. The results that're actually relevant all seem to be talking about organic mercury compounds or large doses of metallic mercury, though. Do please tell me if you strike oil on results page 19, or something.
Oh, and since we seem to be playing the Duelling Experts game with an added coda of Make The Other Guy Humiliate Himself 'Cos He's Wrong, Wrong, Wrong, I hereby require that if your allegation turns out to be misattributed, fictional, published in the Letters section of a medical journal and then misleadingly claimed to have been "published in a peer-reviewed journal", et cetera, you must drop your pants and run seven times around the pool table singing "I've Got A Lovely Bunch Of Coconuts".
You may select a clockwise or anticlockwise run according to your personal preference.
10 May 2013 at 4:07 am
I personally would not worry about the amount of mercury inhaled as the result of a cfl break, for an adult. The problem is that there are NO studies that look at the effects of one of these breakages on children. Also you may want to read the Maine study in a little more depth before stating that all of their mercury all just blows away. The maine study proves that much of the mercry from a breakage become tiny little droplets ( not vapor) and adsorbs to surfaces (carpet, couch, toys, hardwood) and vaporizes for weeks to months after the breakage. Wait I know what you going to say, in tiny amounts. No, near surface readings are relatively high (20,000+ ng/m3), but you just don't put your face there right. Kids crawl on flooring at home, they play with toys in close contact. Here is some math for you. Minimum levels for mercury toxicity in blood are 50 ug per liter. Children have around a liter of blood and breath between .5-1 m3 of air an hour. Mercury vapour is absorbed through the lungs at about an 80% uptake to the bloodstream. Lets take the worst case scenario from the maine study with a 24 hour average of around 5000 ug/m3. Lets take the lower breathing rate. .5 m3 x 24=12. 12x5000=60ug. Poisoning. If they play on contaminated carpet or with contaminated toys, well, you're smart you can do the math on that.
26 May 2013 at 4:34 am
So do you really think a broken cfl isn't really a big deal for a child? Here is a link to a bunch of studies on developing brains They are only on animals but it shows developing brains are more sensitive to elemental mercury vapor (though I don't think that is debatable as they are with all toxins)
http://oehha.ca.gov/air/toxic_contaminants/pdf_zip/Mercury_postSRP3.pdf