38. Strontium: Little Town

Let’s look past the bad reputation this element has to learn how it’s an essential part of an idyllic childhood.

Featured above: Jean-Leon Gerome’s Pollice Verso, a painting featuring several vegetarians.

Show Notes

My Podcast, My Podcast And Me: I mentioned that you can ingest strontium and it “does no harm,” assuming that by now, you’re well aware that if you’re really determined, you could do some damage to yourself with element 38. Recently, I discovered that there’s an episode of Sawbones (a podcast about medical history hosted by Justin McElroy and his wife, Dr. Sydnee McElroy) that’s entirely about Paracelsus. It has the delightful and accurate title, Paracelsus: A Weird Guy Who Did Weird Things And Then Died.

It’s Otherwise A Hard Diet To Stick To: It’s worth noting that those gladiators weren’t exactly vegetarians by choice. Often they were prisoners or slaves, and they had to eat whatever they were given. That weird beverage of ashes they drank was intended to make up for the complete and utter calcium deficit caused by a diet of little else besides barley.

Naming Rights: It’s especially ironic that there’s only one element named after a place in the British Isles, because so many elements were discovered there. By some counts, it’s responsible for more discoveries than any other country!

Worth It? Those strontium supplements are proooobably nothing at all. There is a strontium ranelate supplement that’s available in Europe and Australia that appears to strengthen bones, but no one is quite sure how it works, and it has a host of side effects. The kind you can get over-the-counter in pretty much any country are a different formulation, and are probably not of any great benefit.

The pin that children would receive for sending their baby teeth off to Dr. Reiss.

Do Not Eat: Strontium might be a non-toxic glow-in-the-dark paint, but there are radioactive paints! That’s something we will allmost certainly discuss fifty episodes from now, when we get to radium.

At-Home Particle Accelerators: If that doesn’t ring a bell, head on back and listen to the intro segment from Episode 3, Lithium. (And maybe the rest, too!)

Adult Teeth Get In On The Action: One other source from which you can acquire today’s element is *some* toothpaste for sensitive teeth. Supposedly strontium is an essential part of the active ingredient in some of them. Personally, though, I have some brand-name toothpaste-for-sensitive-teeth in my home, and not a mole of strontium in sight.

Episode Script

When you think of ancient Roman gladiators, you might imagine such bloodthirsty warriors subsisting on a diet of raw meat in between fights to the death. But the fact is, they were almost entirely vegetarian, mostly eating a lot of barley, and drinking a kind of ancient Gatorade that was a slurry of plant ashes.1 2

The University of Vienna team who made this discovery did so, in part, by measuring the amount of strontium in those gladiators’ bones. Plant life, y’see, contains much more strontium than meat, so it’s easy to measure, even in centuries-old remains.3

It’s a simple little story, but packs a lot in that’s relevant to today’s element. From foodstuffs to bone health to explosive acts of violence, strontium has carved out for itself a highly varied yet very distinct niche.

You’re listening to The Episodic Table Of Elements, and I’m T. R. Appleton. Each episode, we take a look at the fascinating true stories behind one element on the periodic table.

Today, we’re accumulating stories about strontium.

Strontian is a modest little town in the Scottish Highlands. It has a population around 400, and didn’t even have a high school until 2002. And it is, of course, the namesake for element 38 on the periodic table — an honor that can be claimed by no place else in the United Kingdom.4

It was founded as a mining town in the early 18th century. Lead was their main product, especially lead for bullets. The mines at Strontian produced nearly all of the bullets fired in the Napoleonic Wars, and captured French soldiers would then be made to work in those mines.5 6

In 1787, someone found an unusual new rock in those lead mines, which made its way into the hands of Edinburgh doctor Adair Crawford, and then another Edinburgh doctor named Thomas Charles Hope. Building on Crawford’s work, Hope discovered that this curious little mineral contained an entirely new element. You might recall that at this point in history, scientists hadn’t yet discovered how to use spectroscopy to identify elements, but Hope did discover that when held to a candle’s flame, strontium turned the flame red — a little fact that turns out to be integral to the element’s identity, as we’ll see later.

You might also remember that our bodies can have a little trouble distinguishing between elements that share a group on the periodic table. Sometimes, this can have fatal consequences — like when arsenic takes the place of phosphorus in ATP molecules. Strontium, however, is far less dramatic. Our bodies often treat it the same as its upstairs neighbor, calcium, but strontium just gets used as an alternative construction material for bones. It doesn’t do any harm. Some people even take strontium supplements, making this another element you can procure by visiting your neighborhood drugstore.

There is one caveat here, though. In Episode 6, Carbon, we learned that an element can come in several varieties, called “isotopes,” that differ based on how many neutrons are in the atom’s nucleus. If the atom possesses too many or too few neutrons, it becomes unstable — AKA, radioactive. Sometimes that’s nothing to worry about, like the small amounts of radioactive potassium present in bananas. But one particular isotope of strontium is very radioactive, and very dangerous.

When the body absorbs strontium-90, it gets deposited in bones and marrow, just like any other isotope of element 38. But once delivered there, it settles in and emits beta radiation, poisoning the body for years or even decades, potentially causing bone cancer and leukemia.

Fortunately, strontium-90 is not a naturally occurring isotope, so it only exists as a byproduct of certain man-made processes. Unfortunately, those man-made processes are nuclear meltdowns and atomic explosions.

Presently, those are both very rare occurrences — a fact we can all be grateful for. But that wasn’t always the case. The bombs above Hiroshima and Nagasaki are the only two ever detonated as an act of war. Between 1945 and 1963, the United States and Soviet Union each detonated hundreds of atomic bombs in atmospheric tests. Clearly it’s less harmful to trigger such an explosion over the barren desert or frozen tundra than a dense city, but that doesn’t mean it’s entirely without dangerous side effects.

For all those years, those hundreds of bombs would create radioactive fallout, including strontium-90, and project it high into the upper atmosphere. From there, it would travel for hundreds or even thousands of miles, falling gently on dairy and vegetable farms all over the world and becoming an inextricable part of millions of people’s diets.7

This radioactive precipitation was invisible to the human eye, but Louise Reiss was one of many doctors who suspected it had terrible and far-reaching side effects. And she came up with a perfect experiment to test that.

Starting in 1959, Reiss worked with schools across the greater St. Louis metropolitan area to get students to mail her their baby teeth whenever they fell out. In her lab, Dr. Reiss would test the concentration of strontium-90 within those teeth. For their assistance, all those junior volunteers received a bright button featuring a beaming gap-toothed face that said, “I gave my tooth to science.”8

The study was well supported, with Dr. Reiss’s office receiving well over three hundred thousand baby teeth over the course of twelve years. Well armed with such plentiful data, it became clear that as time went on, children’s bodies were accumulating frightening amounts of the carcinogenic chemical. By the 1960s, children’s bodies were accumulating more than fifty times more strontium-90 than kids born in 1950.

Dr. Louise Reiss was the director of this study, but it was her husband, Dr. Eric Reiss, who presented these findings before a Senate committee. Two months later, the United States, Soviet Union, and United Kingdom signed the Partial Nuclear Test Ban Treaty. With the signing of this treaty, neither nation could conduct nuclear tests in the open atmosphere, underwater, or outer space, confining such tests to happen only underground.9

The Baby Tooth Survey continued for several years afterward, allowing it to reach an ultimately optimistic conclusion: Children born five years after the signing of the Partial Nuclear Test Ban Treaty exhibited strontium-90 levels that were fifty percent lower than those born before the treaty.

Rarely has a single study been so widely influential, especially when governments are involved. In a letter to a friend, Dr. Louise Reiss wrote, “I continue to be moved by the knowledge that a group of organized people can effectively pressure government if they come up with data instead of rhetoric.”

Radioactive strontium became even less of a hazard following the signing of the Comprehensive Nuclear Test Ban Treaty in 1996, which fully prohibits any nuclear detonations, anywhere for any reason. But that was not the end of element 38’s association with explosions.

One industry in particular has found the red color strontium imparts to a flame to be very useful: fireworks manufacturers. For years, strontium has been the element of choice for lending a bright red hue to those explosions in the sky — proving that, in fact, there *is* a situation where you might want an explosion of strontium to rain down upon children.10

Still, I wouldn’t recommend fussing with the fuse of a firecracker to satisfy your element collection, especially when there are far safer ways to get your hands on it.

Some of the most effective glow-in-the-dark materials are entirely dependent on strontium for their luminescent qualities. While that might appear to make a surface look radioactive, I can assure you it is not. This is the regular old behavior of electrons, similar to that displayed by neon in lamps. The strontium-based paint absorbs the energy of bright light, exciting electrons to occupy higher orbitals, then slowly releasing that energy in the form of (much dimmer) light as those electrons gradually fall back to their ground states.11

In fact, for all the huffing and puffing I’ve just done about radioactive strontium-90, the element’s stable isotopes have played an important role in protecting people from radiation. Back when cathode ray tube televisions were the norm, rather than today’s flatscreens, strontium-infused glass ensured that viewers didn’t receive a deadly dose of x-rays as they sat in front of their at-home particle accelerator.

But nowadays, the place you’re most likely to encounter strontium is stuck to your kitchen. For applications where a magnet’s expense is more important than its strength, like your refrigerator door, strontium ferrite is the compound of choice. So if you have fond memories of fireworks shows, glow-in-the-dark toys, hours in front of the TV, or proudly displaying your latest art class masterpiece on the fridge, it sounds like you can be thankful for a strontium childhood.

Thanks for listening to The Episodic Table of Elements. Music is by Kai Engel. To learn whether those strontium supplements are worth taking, visit episodic table dot com slash S r.

Next time, we’ll visit another tiny town that’s had a huge influence with yttrium.

Until then, this is T. R. Appleton, reminding you that the food we eat in life echoes in eternity.


  1. Science Daily, Roman Gladiators Ate A Mostly Vegetarian Diet And Drank A Tonic Of Ashes After Training. Medical University Of Vienna, October 20, 2014.
  2. BBC News, Gladiators Were “Mostly Vegetarian”. Sean Coughlan, October 22, 2014.
  3. Archaeology Archive, The Gladiator Diet. Andrew Curry, November/December 2008.
  4. BBC News, Pupils Celebrate Metal Discovery. June 27, 2008.
  5. Scotland Highlands & Islands Footprint Handbook, p. 219. Alan Murphy, 2014.
  6. I Never Knew That About Scotland, p. 26. Christopher Winn, 2012.
  7. The American Journal Of Public Health, A Public Health Perspective On Strontium-90. August, 1960.
  8. The New York Times, Dr. Louise Reiss, Who Helped Ban Atomic Testing, Dies At 90. Dennis Hevesi, January 10, 2011.
  9. St. Louis Magazine, How To Stop A Nuclear Bomb: The St. Louis Baby Tooth Survey, 50 Years Later. Rosalind Early, September 20, 2013.
  10. Nature, In Your Element: Strontium’s Scarlet Sparkles. Francois-Xavier Coudert, October 2015.
  11. Chemistry World, Strontium Aluminate. Brian Clegg, February 1, 2018.

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