Life expectancy vs Lead exposure?

[Alex Eisenhut]

Maybe if you make a smoothie out of the boards and drink one every day.

Ask yourself this.

People have been using stuff like this

for decades. There would have been something happening by now?

[bjdhjy888]

Normal soldering temperatures are far too low to cause any lead vapour to form.

https://en.wikipedia.org/wiki/Lead

I just looked up the boiling point of lead on Wikipedia, where it says it's 1749 °C. Does this mean that we can only inhale lead or absorb lead through our skin when our soldering iron's tip reaches a temperature of 1749 °C?
If yes, then I feel super safe now..
 

[tautech]

Maybe if you make a smoothie out of the boards and drink one every day.

Ask yourself this.

People have been using stuff like this
(Attachment Link)
for decades. There would have been something happening by now?

Yep we used to carry them around in our mouth before we knew better. 

[james_s]

Leaded gasoline was probably the worst of all by a wide margin. It was atomized and spread all over the planet, during the heyday of leaded gas it was inescapable.

From the man who also brought us CFCs! Sometimes you just can't catch a break.

To their credit, CFCs are relatively nontoxic, nonflammable and generally inert substances. Nobody realized they would break down the ozone layer, that could have really been a disaster without modern science to detect it and determine the cause.

[maginnovision]

I worked in electronics manufacturing for years using leaded processes. Never got sick or had problems and I'm an asthmatic. Only time I took precautions was cleaning dross from the wave solder machine. I'd wear a mask and gloves(mostly due to the heat). Even if you're just using a soldering iron and a fan you'll be fine. If you didn't use a fan I'd just recommend taking a break before you get a sore throat, drinking water at regular intervals, and taking a shower at the end of the day(with lots of steam) to help cough up anything you managed to get in your lungs.

[Mr. Scram]

I worked in electronics manufacturing for years using leaded processes. Never got sick or had problems and I'm an asthmatic. Only time I took precautions was cleaning dross from the wave solder machine. I'd wear a mask and gloves(mostly due to the heat). Even if you're just using a soldering iron and a fan you'll be fine. If you didn't use a fan I'd just recommend taking a break before you get a sore throat, drinking water at regular intervals, and taking a shower at the end of the day(with lots of steam) to help cough up anything you managed to get in your lungs.

What's being asthmatic got to do with lead poisoning?

[maginnovision]

Nothing it has to do with irritation from flux fumes.

[SkyMaster]

According to Thomas Midgley, lead is inoffensive.

Thomas Midgley was an engineer. He was then probably right.

https://en.wikipedia.org/wiki/Thomas_Midgley_Jr.


Wait, he also invented Freon...


 

[Nominal Animal]

You don't want to eat and drink from lead (or uranium) platters and goblets every day for years, but doing it once hurts you less than breathing in in any densely populated city.

If you do not have open wounds or sores, handling heavy metals like lead or mercury is safe.  Just wash your hands afterwards, so you do not end up ingesting them.
(If you do have wounds or sores, it depends on the material structure.  Usually it does not matter.  The risk, really, is getting some lodged in the wound, so your immune system tries to slowly digest it.  You wouldn't want to deal with heavy metal powders with your bare hands, if you have cuts in your hands.  Just use gloves then.)

Welding and soldering generates fumes.  Welding generates metal vapor (zinc vapor being particularly nasty) and small metal particulates, and both welding and soldering vaporizes some of the flux.  These are most chemically active when hot, so you don't want to breath them in fresh.  If the small particulates are still hot when they get in your lungs, they can embed themselves in the tissues, and since there is a lot of blood flow there, it is not far off from getting them directly in your bloodstream.  So that's bad.  Venting the fumes cools them down, making them much, much less chemically active and thus much less dangerous, and mixing them to the ambient outside air reduces their density to safe levels.  The fumes are much more dangerous in closed spaces: that's why you should always weld outside or a special room with fume extraction and/or air filtration.

If say a factory or a hack lab has welding or soldering stations, they should have an air filter unit.  However, this too is a balance: making such air filters takes resources and generates pollution, so such an air filter really should be used enough to warrant itself, or it will be a net loss for the environment.

Environmental risk management is something where you need both rational thinking, and a wide range of facts to rely on.  (For example, like ²³⁸U being a heavy metal and dangerous due to its chemistry, like lead and mercury, and not because it is radioactive.)
It truly is pity that leaded solder is considered dangerous, as the amounts used are minuscule compared to other industries, and the way they are used means the lead is in environmentally pretty safe alloys.  The chemically harsher fluxes needed with non-leaded solders probably negates any benefits anyway.

Anyway, the small bit of 60/40 solder I just ate, didn't taste of anything.  Explains why the Romans used lead in their dinnerware.  Stainless steel has much more of a "metallic" taste.  If I get sick, it would be because of the flux in it.  I won't, though.

[janoc]

I always use disposable gloves. When cleaning out the brass wool, there's a lot of fine lead, almost powdered. I would imagine that poses the greatest risk, as it puts a lot of particles in the air, and they would dissolve the easiest.

Lead really doesn't dissolve easily, not even in acids or strong bases. So no need to panic over that - you most likely don't have anything on or near the bench that could cause it to dissolve in a meaningful time frame. If you put that lead somewhere into a landfill and let it sit in an acid rain or leach into water for years, that would be a different matter.

And those shavings that you clean out of your tip cleaning wool are way too large and heavy to fly far by air (assuming you are not waving the wool around). Those particles would need to be order of magnitude or two smaller to be a meaningful hazard.

Just bear in mind that children are especially susceptible to lead ingestion and may suffer irreversible developmental issues. Unless you lick your fingers after soldering you'll probably be fine but keep it away from children. Also note that while washing your hands with water and soap to remove lead is effective it isn't quite perfect.

If you are afraid that small kids could put it in their mouth and such - if the kids can get to your solder, they most likely can get also to the hot iron or sharp tools on your desk. I would consider that a much bigger issue than a kid licking a solder wire once or twice or touching the wire and then licking their fingers. You really don't die or turn into a babbling drooling vegetable from a tiny exposure like that. Unless that kid is doing that every day for a while, they will likely be fine.

Also, if someone is worried about lead poisoning from a leaded solder - we have lead-free solder too 

Normal soldering temperatures are far too low to cause any lead vapour to form.

https://en.wikipedia.org/wiki/Lead

I just looked up the boiling point of lead on Wikipedia, where it says it's 1749 °C. Does this mean that we can only inhale lead or absorb lead through our skin when our soldering iron's tip reaches a temperature of 1749 °C?
If yes, then I feel super safe now..
 

Boiling point of a substance has literally zero to do with vapor forming. Water also doesn't start to evaporate only once it reaches the boiling temperature! Boiling point is only the temperature when the substance is evaporating from the entire volume (that's what produces the bubbles) and not only the surface.

Vapors can form even when the matter is still solid (sublimation - even solid lead sublimates under certain conditions) or liquid but below the boiling point.

(Pure) lead melts at 327°C and starts releasing fumes at 480°C or so. Common soldering (especially given that we use lead-tin alloys that melt at even lower temperatures than this) has no way to reach that unless you are using a flame thrower to solder.

[janoc]

cheap white mouth-nose protector with elastic thingie,

That will literally do nothing apart from providing you with the feel-good reassurance. Those protectors are only against dust, they don't protect against gases (e.g. flux, lead or paint fumes). Even for dust they aren't great - e.g. almost useless against FR4 or similarly sized fine dust. Those things are really for woodworkers, construction workers demolishing walls and such only.

If you want to protect yourself against fine dust, you need a proper respirator and if you wanted to protect yourself against gases, then you would need a gas mask with a filter matched to the toxins you want to keep out.

[Mr. Scram]

Lead really doesn't dissolve easily, not even in acids or strong bases. So no need to panic over that - you most likely don't have anything on or near the bench that could cause it to dissolve in a meaningful time frame. If you put that lead somewhere into a landfill and let it sit in an acid rain or leach into water for years, that would be a different matter.

And those shavings that you clean out of your tip cleaning wool are way too large and heavy to fly far by air (assuming you are not waving the wool around). Those particles would need to be order of magnitude or two smaller to be a meaningful hazard.

If you are afraid that small kids could put it in their mouth and such - if the kids can get to your solder, they most likely can get also to the hot iron or sharp tools on your desk. I would consider that a much bigger issue than a kid licking a solder wire once or twice or touching the wire and then licking their fingers. You really don't die or turn into a babbling drooling vegetable from a tiny exposure like that. Unless that kid is doing that every day for a while, they will likely be fine.

Also, if someone is worried about lead poisoning from a leaded solder - we have lead-free solder too 

Boiling point of a substance has literally zero to do with vapor forming. Water also doesn't start to evaporate only once it reaches the boiling temperature! Boiling point is only the temperature when the substance is evaporating from the entire volume (that's what produces the bubbles) and not only the surface.

Vapors can form even when the matter is still solid (sublimation - even solid lead sublimates under certain conditions) or liquid but below the boiling point.

(Pure) lead melts at 327°C and starts releasing fumes at 480°C or so. Common soldering (especially given that we use lead-tin alloys that melt at even lower temperatures than this) has no way to reach that unless you are using a flame thrower to solder.

It's not about licking a roll of solder, it's about ingesting particulates like the solder balls that tend to form. This represents a relevant amount of lead although a single isolated exposure is unlikely to do a lot of long term harm. Particulates being under the desk or spread throughout the house as they cling to soles can be a concern.

[janoc]

It's not about licking a roll of solder, it's about ingesting particulates like the solder balls that tend to form. This represents a relevant amount of lead although a single isolated exposure is unlikely to do a lot of long term harm. Particulates being under the desk or spread throughout the house as they cling to soles can be a concern.

Hum, clean your workshop periodically and don't fling solder all over the place in the first place? Those solder balls tend to be pretty macroscopic too. I can understand bits of solder on the bench but if you are worried about them being spread by soles all over the house it sounds like a major cleanup is in order. I solder quite a bit and for some reason don't have solder balls on the floor or in the carpet.

And teach your kids to not put whatever crap they find in the mouth. Frankly, in an average household there are much worse and immediately toxic things I would be worried about a child putting in their mouth than solder particulates on the floor.

But again, if you are worried about the kids, lead-free solder does exist ...

[Mr. Scram]

Hum, clean your workshop periodically and don't fling solder all over the place in the first place? Those solder balls tend to be pretty macroscopic too. I can understand bits of solder on the bench but if you are worried about them being spread by soles all over the house it sounds like a major cleanup is in order. I solder quite a bit and for some reason don't have solder balls on the floor or in the carpet.

And teach your kids to not put whatever crap they find in the mouth. Frankly, in an average household there are much worse and immediately toxic things I would be worried about a child putting in their mouth than solder particulates on the floor.

But again, if you are worried about the kids, lead-free solder does exist ...

We can disparage the risk all day long but it's an avenue of exposure that should be given some thought given the susceptibility of children. Though lead-free solder doesn't exist just to protect the children.

[dom0]

Personally I don't usually bother with the fume extractor for small stuff unless I am working with verowire, which releases rather toxic fumes when you burn the insulating PU lacquer off. I am one of those guys who inhales before soldering and blows at the rosin smoke (it's automated). I use eutectic lead solder with a mild, modified rosin core for most things. (F-SW-31/1.1.1/ROL0).

My fume extractor goes directly out the window, making it my neighbours problem. I wouldn't put too much trust into those little "PC fan with activated carbon mat" fume extractors.

[soldar]

https://nypost.com/2019/08/19/lead-scrubbed-from-paris-streets-as-notre-dame-work-resumes/

PARIS — Specialists shoring up fire-damaged Notre Dame Cathedral returned Monday to the Paris site for the first time in nearly a month, this time wearing disposable suits and other protective gear after a delay prompted by fears of lead contamination.

Meanwhile, cleanup teams swept, sprayed and vacuumed neighboring streets Monday to scrub away any lead left over from the April blaze that destroyed Notre Dame’s roof and toppled its spire. Toxic dust spewed into the air as hundreds of tons of lead melted in the fire.

At the cathedral itself, activity resumed Monday under strict new lead protection measures for the stonemasons, cleanup workers and scientists working on the monument, according to the Culture Ministry. They include throwaway full-body clothing, obligatory showers and a new decontamination zone to ensure that no one tracks pollution outside the site.

[dom0]

When stuff burns everything gets turned into fine and ultra-fine particulates. Same with lead. They are worried about dust and particulates contaminated with leaded compounds.

[Old Printer]

https://nypost.com/2019/08/19/lead-scrubbed-from-paris-streets-as-notre-dame-work-resumes/

PARIS — Specialists shoring up fire-damaged Notre Dame Cathedral returned Monday to the Paris site for the first time in nearly a month, this time wearing disposable suits and other protective gear after a delay prompted by fears of lead contamination.

Meanwhile, cleanup teams swept, sprayed and vacuumed neighboring streets Monday to scrub away any lead left over from the April blaze that destroyed Notre Dame’s roof and toppled its spire. Toxic dust spewed into the air as hundreds of tons of lead melted in the fire.

At the cathedral itself, activity resumed Monday under strict new lead protection measures for the stonemasons, cleanup workers and scientists working on the monument, according to the Culture Ministry. They include throwaway full-body clothing, obligatory showers and a new decontamination zone to ensure that no one tracks pollution outside the site.

Industries will appear where ever there is money.

Besides working with lead most of my life, I spent a good number of years competing in indoor small bore rifle matches. In those days most indoor ranges did not have air scrubbing systems. My doctor suggested having my blood lead level checked at my yearly physical. As I recall it was a pretty minimal expense, and my results were never out of the normal range. So if anyone is concerned about their exposure, it's not hard or expensive to get it checked at your next physical. Lead in developing brains can have serious long term effects, but in healthy adults treating it as uranium is fear mongering IMO.

[bjdhjy888]

I felt super safe when I was reading you guys' replies.

Then....when I was soldering my STM32 a moment ago, my air quaility meter read:
PM 2.5   100+ ug/sq meters
PM 10    300+ ug/sq meters

OMG!

I tried to read the numbers with my door closed and open, while my fan was working, blowing fumes out of my window. Either way, the numbers were all above 100+, up to 300+
I used lead solder and solder paste.

The readings dropped to 63 and 109 respectively, after 30 minutes.

 

[janoc]

We can disparage the risk all day long but it's an avenue of exposure that should be given some thought given the susceptibility of children. Though lead-free solder doesn't exist just to protect the children.

Christ ... Do you know that even drinking water can kill you? (no kidding). Or you could get hit by a meteorite.  I guess we better don't drink and stay indoors 24/7 then.

It is not about disparaging anything but about evaluating the consequences vs real exposure risks instead of falling for hysterical  alarmist bullshit.

[janoc]

https://nypost.com/2019/08/19/lead-scrubbed-from-paris-streets-as-notre-dame-work-resumes/

PARIS — Specialists shoring up fire-damaged Notre Dame Cathedral returned Monday to the Paris site for the first time in nearly a month, this time wearing disposable suits and other protective gear after a delay prompted by fears of lead contamination.

Meanwhile, cleanup teams swept, sprayed and vacuumed neighboring streets Monday to scrub away any lead left over from the April blaze that destroyed Notre Dame’s roof and toppled its spire. Toxic dust spewed into the air as hundreds of tons of lead melted in the fire.

At the cathedral itself, activity resumed Monday under strict new lead protection measures for the stonemasons, cleanup workers and scientists working on the monument, according to the Culture Ministry. They include throwaway full-body clothing, obligatory showers and a new decontamination zone to ensure that no one tracks pollution outside the site.

How is that relevant to this topic? Nobody is disputing that lead is toxic.

You do realize that there are a few hundreds of tons of lead melted there and toxic dust from the fire, right? None of which you are likely to have in your workshop.

[Mr. Scram]

Christ ... Do you know that even drinking water can kill you? (no kidding). Or you could get hit by a meteorite.  I guess we better don't drink and stay indoors 24/7 then.

It is not about disparaging anything but about evaluating the consequences vs real exposure risks instead of falling for hysterical  alarmist bullshit.

I'm sure the French government is spending millions to clean up due to "alarmist bullshit" instead of actual risks? Actual research shows lead intake is cumulative and definitely harmful at blood levels of 10 µg/dL. It could be worse though. "There is no known safe blood lead concentration. But it is known that, as lead exposure increases, the range and severity of symptoms and effects also increases. Even blood lead concentrations as low as 5 µg/dL, once thought to be a “safe level”, may be associated with decreased intelligence in children, behavioural difficulties, and learning problems." You won't keel over instantly and the biggest risk is definitely associated with children but it is a veritable toxin and should be handled with consideration.

[Nominal Animal]

• Lead salts are most dangerous, because they are very efficiently absorbed into the body.
• When ingested, adult bodies absorb only about 1% of pure lead, the rest is excreted in a few weeks.
• When ingested, child bodies absorb about 33% of pure lead.
• Nanoparticles and very fine dust easily lodges in human lungs.
  The smaller a particle has, the larger surface-to-volume ratio it has.  Because the surface is where chemical reactions occur, the same weight or volume of nanoparticles causes an order of magnitude more chemical reactions than a single nonporous chunk.  This is how car catalysers work.
  Because of their reactivity, nanoparticles can easily embed themselves in lung tissue, and even enter the blood stream.
• Adult human bodies contain about 0.1g of lead, total, on average.

I recently ingested a cubic millimeter of 60-40 lead alloy, containing about 0.7 mg of lead.  If this was pure lead, my body would retain about 1% of it, or about 1 µg.  This increases the amount of lead in my body by about 0.001%.  Let's say I repeat this every day for a year, accumulating about 400 µg = 0.4 mg of lead into my body.  That is still only a 0.4% increase in the amount of lead in my body.  I could do this for the rest of my life, and even if I were to live to be 100 years old, I'd only increase the lead content in my body by about 25%.  It is not enough to raise the coroners eyebrow: where you live and what kind of air you breath, makes a bigger difference.

So, worrying about millimeter-sized lead or lead-alloy spherules only matters if you have kids.

Statistically, if we were to increase the lead load by 25% for an entire population, we'd likely see some negative health effects.  This is why banning lead paint is a good idea, especially for toys.  (The lead in lead paint is in suspension, and can be in basically nanoparticle form.  Same for lead additives in fuels.  Lead salts are even worse, because almost all of them get absorbed into the body when ingested.)

But, as you can see from the above calculation, the amount of lead in solder and how it is in a form so unlikely to get into human bodies, makes leaded/unleaded solder discussion completely wacky.  Electronics already contain much worse chemicals making it necessary to dispose of them properly (to avoid negative health effects on the human population), and leaded/unleaded solder has an utterly insignificant effect there.

[james_s]

I felt super safe when I was reading you guys' replies.

Then....when I was soldering my STM32 a moment ago, my air quaility meter read:
PM 2.5   100+ ug/sq meters
PM 10    300+ ug/sq meters

OMG!

I tried to read the numbers with my door closed and open, while my fan was working, blowing fumes out of my window. Either way, the numbers were all above 100+, up to 300+
I used lead solder and solder paste.

The readings dropped to 63 and 109 respectively, after 30 minutes.

 

What exactly does your air quality meter measure? These are not typically precision devices, the one built into a room air filter thing we have pegs every time I fire up the gas oven in the kitchen or use a squirt of canned air across the room. It only measures certain characteristics, it doesn't really tell you with any certainty what it has detected or whether it is harmful.

[Mr. Scram]

• Lead salts are most dangerous, because they are very efficiently absorbed into the body.
• When ingested, adult bodies absorb only about 1% of pure lead, the rest is excreted in a few weeks.
• When ingested, child bodies absorb about 33% of pure lead.
• Nanoparticles and very fine dust easily lodges in human lungs.
  The smaller a particle has, the larger surface-to-volume ratio it has.  Because the surface is where chemical reactions occur, the same weight or volume of nanoparticles causes an order of magnitude more chemical reactions than a single nonporous chunk.  This is how car catalysers work.
  Because of their reactivity, nanoparticles can easily embed themselves in lung tissue, and even enter the blood stream.
• Adult human bodies contain about 0.1g of lead, total, on average.

I recently ingested a cubic millimeter of 60-40 lead alloy, containing about 0.7 mg of lead.  If this was pure lead, my body would retain about 1% of it, or about 1 µg.  This increases the amount of lead in my body by about 0.001%.  Let's say I repeat this every day for a year, accumulating about 400 µg = 0.4 mg of lead into my body.  That is still only a 0.4% increase in the amount of lead in my body.  I could do this for the rest of my life, and even if I were to live to be 100 years old, I'd only increase the lead content in my body by about 25%.  It is not enough to raise the coroners eyebrow: where you live and what kind of air you breath, makes a bigger difference.

So, worrying about millimeter-sized lead or lead-alloy spherules only matters if you have kids.

Statistically, if we were to increase the lead load by 25% for an entire population, we'd likely see some negative health effects.  This is why banning lead paint is a good idea, especially for toys.  (The lead in lead paint is in suspension, and can be in basically nanoparticle form.  Same for lead additives in fuels.  Lead salts are even worse, because almost all of them get absorbed into the body when ingested.)

But, as you can see from the above calculation, the amount of lead in solder and how it is in a form so unlikely to get into human bodies, makes leaded/unleaded solder discussion completely wacky.  Electronics already contain much worse chemicals making it necessary to dispose of them properly (to avoid negative health effects on the human population), and leaded/unleaded solder has an utterly insignificant effect there.

Where did you grab those numbers on lead absorption?