https://phys.org/news/2025-01-pollution-widespread-iq-declines-ancient.html
Lead exposure is responsible for a range of human health impacts, with even relatively low levels impacting the cognitive development of children. DRI scientists have previously used atmospheric pollution records preserved in Arctic ice cores to identify periods of lead pollution throughout the Roman Empire, and now new research expands on this finding to identify how this pollution may have affected the European population.
The study, published Jan. 6 in Proceedings of the National Academy of Sciences, examined three ice core records to identify lead pollution levels in the Arctic between 500 BCE through 600 CE. This era spans the rise of the Roman Republic through the fall of the Roman Empire, with the study focusing on the approximately 200-year height of the Empire called the Pax Romana.
Lead isotopes allowed the research team to identify mining and smelting operations throughout Europe as the likely source of pollution during this period. Advanced computer modeling of atmospheric movement then produced maps of atmospheric lead pollution levels across Europe. Combined with research linking lead exposure to cognitive decline, the research team also identified likely reductions in IQ levels of at least 2 to 3 points among the European population.
"This is the first study to take a pollution record from an ice core and invert it to get atmospheric concentrations of pollution and then assess human impacts," says Joe McConnell, research professor of hydrology at DRI and lead author of the study. "The idea that we can do this for 2,000 years ago is pretty novel and exciting."
Journal Reference: McConnell, Joseph R., Pan-European atmospheric lead pollution, enhanced blood lead levels, and cognitive decline from Roman-era mining and smelting, PNAS (2025). DOI: 10.1073/pnas.2419630121
(Score: -1, Troll) by Anonymous Coward on Wednesday January 08, @07:56AM (1 child)
The Americas weren't yet discovered at the time and so the USians were the smartest.
(Score: -1, Troll) by Anonymous Coward on Wednesday January 08, @09:39AM
You mean: how come, all the lead retarded Romans emigrated to the US?
(Score: 3, Insightful) by looorg on Wednesday January 08, @09:16AM (11 children)
Wasn't this already known? Drinking wine, or anything, out of lead cups isn't great. Eating or powdering your face, or wigs, with arsenic isn't great either. Yet ancient man did it. Looked nice and was cheap. So it's not hard to imagine that there was higher concentrations of lead etc in the air.
I guess we didn't learn to much from it at the time tho since we kept on using lead pipes and such for along time after ancient Roman times. That said it wasn't long ago since they wanted us to learn things from "ancient" mining techniques. I guess they were not that great either then ...
(Score: 4, Interesting) by RamiK on Wednesday January 08, @12:00PM (3 children)
It's about atmospheric levels across Europe, especially in villages vs. cities, rather than what people were exposed to from pipes and utensils:
( https://www.pnas.org/doi/10.1073/pnas.2419630121 [pnas.org] emphasis mine )
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(Score: 4, Informative) by JoeMerchant on Wednesday January 08, @06:07PM (2 children)
Lead exposure from pipes depends on the water chemistry, acidic water will leach lead from plumbing into the water, but then it will also quickly deteriorate lead pipes so they wouldn't be used for a very long time carrying acidic waters. Most water is basic enough to cause lead to self-seal much like aluminum oxide prevents aluminum corrosion.
Breathing lead (as one does when it's burned in internal combustion engines) is a much more effective way to get a bio-available dose.
Of course, radon gas is another fun route to inhaled lead poisoning, but instead of getting "leaded" right away, the radon is inhaled, and slowly decays [wikipedia.org] while emitting ionizing particles along the way, giving a pretty good shot at lung cancer before the lead exposure becomes too troubling, unless you're getting supplemental lead from other sources too.
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(Score: 2) by RamiK on Wednesday January 08, @09:31PM (1 child)
I'm guessing lead utensils and cookware were also prevalent in every day use.
Regardless, I think the major pollutant in ancient times was the charcoal/wood used to light fires.
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(Score: 2) by JoeMerchant on Wednesday January 08, @11:47PM
As I understand it, syphilis and gonorrhea were big killers in the more urban settings as well - thus: God's wrath visiting those who sleep around, etc.
I wouldn't be surprised if pollution exposure varied dramatically from place to place even within the cities. Some people lived on top of the hill with nothing emitting foul odors that would reach them, others were coerced to live next to the smelters...
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(Score: 2) by JoeMerchant on Wednesday January 08, @12:14PM (6 children)
I recall being taught about Roman lead issues in the 2980s, pretty sure my parents learned about it in the 1960s.
Worth mentioning: Contribution of childhood lead exposure to psychopathology in the US population over the past 75 years
https://acamh.onlinelibrary.wiley.com/doi/10.1111/jcpp.14072 [wiley.com]
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(Score: 5, Funny) by Thexalon on Wednesday January 08, @01:18PM (3 children)
As a time traveler, of all the times you could have picked, why did you decide to show up now?
"Think of how stupid the average person is. Then realize half of 'em are stupider than that." - George Carlin
(Score: 2) by JoeMerchant on Wednesday January 08, @05:59PM (2 children)
It's the lead poisoning, not only does it give digital palsy, it makes one forgetful, prone to slip and reveal one's true birthdate.
I definitely remember watching dad fill up with leaded gas at the pump in the early 70s.
All of this has happened before, and will happen again. [stackexchange.com]
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(Score: 2) by mcgrew on Thursday January 09, @07:19PM (1 child)
I definitely remember watching dad fill up with leaded gas at the pump in the early 70s.
So did I. My '69 Mustang I bought in the USAF ran on leaded gas. I'd blame my forgetfulness on leaded gas, but I'm pretty sure it was the unleaded grass :)
There was a story, probably bullshit, that a woman died after eating mushrooms picked by a highway in the 1960s. They thought she had ingested the wrong species of mushroom, until the coroner ruled lead poisoning. Again, it's probably urban legend but I found it interesting.
A man legally forbidden from possessing a firearm is in charge of America's nuclear arsenal. Have a nice day.
(Score: 2) by JoeMerchant on Thursday January 09, @08:58PM
In grad school I had a landlord with a super mean and annoying Chow Chow dog that roamed freely outside my door.
I fed it lots of lead foil, wrapped in meat. It never changed its disposition, much less killed it. Too bad I didn't have access to the special (likely imaginary) mushrooms from your legend.
For the cruelty to animals crew, you need to understand, this was the third Chow Chow in less than a year. The landlord's 8 year old son had daddy issues (as in: daddy's in federal pen for fencing stolen cars...) and he would whip the dogs with sticks, which didn't improve their dispositions. The first two dogs turned against the family and they got rid of them, but this third dog was older and must have developed a kind of Stockholm Syndrome because it kept coming back for more whippings from the boy... Not that that excuses my young actions of feeding a poor defenseless animal that snarled and snapped at me every time I walked by, that would bark anytime I moved inside my apartment any hour of the day or night, lead foil wrapped in tasty treats. No, that was a very bad thing that you should never encourage anyone to do, because it clearly didn't work.
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(Score: 2) by mcgrew on Thursday January 09, @07:12PM
I was in high school in the 1960s. Then, it was hypothesis/theory. The theory has now been proven. It's like black holes; they only existed in theory for decades, until Cygnus X-1 was found.
A man legally forbidden from possessing a firearm is in charge of America's nuclear arsenal. Have a nice day.
(Score: 2) by mcgrew on Thursday January 09, @07:14PM
I recall being taught about Roman lead issues in the 2980s
Say "hi" to Rority and Doctor Who for me, would you?
A man legally forbidden from possessing a firearm is in charge of America's nuclear arsenal. Have a nice day.
(Score: 4, Interesting) by VLM on Wednesday January 08, @12:56PM (8 children)
To provide some perspective, its not even remotely controversial in the USA to intentionally add fluoride to water to rise to a level of 0.7 mg/L
However, here's a USA NIH report :
https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/completed/fluoride [nih.gov]
So, the Romans may have accidentally dropped their IQ by 2 or 3 points, but the Americans intentionally drop their kids IQs by a little more than one point.
The irony is topical fluoride (smeared on teeth for awhile) has a positive effect on teeth, but drinking it has no real medical effect other than making kids dumber and some mood altering effects. Its probably a good idea to add it to toothpaste that you spit out and probably a very bad idea to add it to the water supply.
My point of the above is the result is kind of "meh". There are places with natural fluoride levels high enough to cause a larger IQ decrease, and people in general really don't care if their kids are dumber as long as the social media of the day supported it. We could go back to the days of using lead salts as a food sweetener and adding it back to gasoline and it would be just fine as long as there's enough centrally controlled propaganda in support. Would not be surprised to see tetraethyl lead back on the shelves as an octane booster within my lifetime. After all, in the current year, carbon is worse than lead amirite?
(Score: 3, Informative) by Username on Wednesday January 08, @03:00PM (2 children)
I remember having to "swish" fluoride and drink it when I was in elementary school. I always questioned that.
(Score: 2) by VLM on Wednesday January 08, @04:37PM
Topically it works well to prevent tooth decay but ingestion is a bad idea. Its about half as bad as the lead in the article, according to our own government, which nobody trusts, so its probably worse LOL.
(Score: 3, Informative) by aafcac on Wednesday January 08, @05:43PM
And drink it? Every fluoride containing product that I've ever bought has explicit warnings not to drink it, and that if you manage to swallow more than what you'd naturally swallow while using it properly, to seek medical attention. The amount of fluoride in tap water is pretty low, the there's a much higher concentration in fluoride containing products to help ensure that an adequate amount gets into the teeth during the short period during which it is in contact with them.
(Score: 3, Informative) by aafcac on Wednesday January 08, @05:41PM
1.63 IQ points is pretty much nothing. Chances are that just taking the test on different days could provide more of a variation than that in individual test takers.
I do personally question, how much good fluoride in the water does, when it has such limited contact with the teeth and when there are other options like putting it in toothpaste, mouth wash and other things which do contact the teeth for longer. It's not like people commonly swish their water around in their mouths when drinking.
I'm not suggesting that that's enough to justify it's removal, just that perhaps we should be really considering other things like making sure everybody has dental care rather than arguing over whether there should be fluoride in the water.
(Score: 4, Interesting) by JoeMerchant on Thursday January 09, @02:55AM
>The meta-analysis found that for every 1 mg/L increase in urinary fluoride, there is a decrease of 1.63 IQ points in children.
You got extra fluoride treatments as a child, during the leaded gasoline years, amirite?
> in the USA to intentionally add fluoride to water to rise to a level of 0.7 mg/L
That's the tap water. How much of your total water intake comes from tap water sources as opposed to milk, juice, soda, fruits, etc.?
Did the meta-analysis establish linearity down to 0 for the IQ / urinary fluoride concentration correlation? Most such effects have a minimum threshold dose before any significant effects can be observed or even implied. Even when there are very low dose effects, the dose-response curve is rarely linear. https://en.wikipedia.org/wiki/Dose%E2%80%93response_relationship [wikipedia.org]
>probably a very bad idea to add it to the water supply.
Depending on who you listen to... "Science" from the time of Dr. Strangelove's screenplay writing up until very very recently was "settled" on the conclusion that population level benefits in dental health outweighed any undesired side effects / risks. My flouride fuzzed memory (from childhood, we haven't had fluoride in our household drinking water for the past 12 years - deep well source) seems to recall that scientists observed much greater resistance to tooth decay in some natural populations as compared with others, and they established not only a correlation with natural levels of fluoride in the local drinking water, but also a causal relationship between the fluoride and the mineralization strength of human teeth.
I'm sure JFK Jr. and his DDS friends would love to wipe fluoridation out of all US municipal water systems without a further thought, based on a few recently published studies (of dubious backing) which have suggested what you are saying here: fluoride treatments for teeth should only be administered by dental professionals for a fee, rather than distributed to everyone for free. Maybe they're right, but for 60 years the preponderance of the "Science" has pointed against them.
I would dig into the more recent contradicting studies and take a hard look at how and why they were done (follow the money) before drawing the conclusion that newer opinions must be better than 60 years of established population level results.
One little IQ aside note: our well water comes with significant quantities of dissolved H2S, which we treat somewhat aggressively to outgas outside the house instead of smelling the stinky sulfur indoors. Apparently it's not just stinky, chronic exposure to low levels H2S gas has been shown to have significant negative effects on IQ - which goes a long ways toward explaining most of the people I know from central Florida. The studies point to a fairly high threshold dose for H2S cognitive effects. If you order a glass of water in a restaurant in Arcadia, Florida you'll be served something harsh to outsiders, but unremarkable to the locals who drink worse than that from their home well systems.
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(Score: 1, Interesting) by Anonymous Coward on Thursday January 09, @09:07AM
That is not correct. Approximately half of the fluoride ingested ends up deposited in the skeleton. It significantly increases bone density, but without increasing bone strength. As a result, fluoride ingestion is very strongly correlated with hip fractures in the elderly.
(Score: 2) by mcgrew on Thursday January 09, @07:30PM (1 child)
From TFA: some pregnant women and children may be getting more fluoride than they need because they now get fluoride from many sources
Your comment: The irony is topical fluoride (smeared on teeth for awhile) has a positive effect on teeth, but drinking it has no real medical effect other than making kids dumber and some mood altering effects
From what I've read, that's backwards; the fluoride has to be ingested, not just smeared on teeth. 1.5 milligrams of fluoride per liter is an awful lot. Do any municipalities add that much?
A far more prevalent and powerful cause of lowered IQ in children is pregnant drinking. There's no comparison between wine and fluoride. A drunken pregnant woman is unlikely to have a child with an IQ over 70.
A man legally forbidden from possessing a firearm is in charge of America's nuclear arsenal. Have a nice day.
(Score: 1, Interesting) by Anonymous Coward on Friday January 10, @11:33AM
You are completely wrong about fluoride. "Smearing" fluoride on teeth replaces hydrogen ions in some of the dental compounds and makes them more acid resistant. It is a surface phenomenon that toughens enamel.
Ingesting fluoride is a very bad idea. 50% of what you ingest gets deposited in the bones, decreasing their strength to weight ratio significantly.
(Score: 0) by Anonymous Coward on Wednesday January 08, @07:14PM
> Lead Pollution Likely Caused Widespread IQ Declines in Ancient Rome
The Romans had IQ testing? If so, that's the big news here...
(Score: 2) by JoeMerchant on Thursday January 09, @12:18AM
Same story, different filter... I'm wondering if Google is snooping my Soylent browsing and feeding me related articles now:
https://www.sciencealert.com/roman-empires-air-pollution-may-have-lowered-the-iq-of-europe [sciencealert.com]
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(Score: 4, Informative) by Zoot on Thursday January 09, @02:59AM
Only 100 years ago, before 1924, we didn't have iodized salt and the lack of dietary iodine in many populations, especially for example the US Midwest, was responsible for substantially reduced IQ as well as an epidemic of neck goiters.
It is now estimated that the switch to iodized salt raised the average IQ by 15 points in these areas.