Everything Everywhere Daily: History, Science, Geography & More - A History of Lead (Encore)

Starting point is 00:00:00 The following is an encore presentation of Everything Everywhere Daily. Sometime around 8,000 to 9,000 years ago, ancient people in Asia Minor found a very dull gray metal that turned out to be easy to manipulate when it was heated. For thousands of years, it was used for a variety of purposes, including as a food additive. With the advent of the Industrial Revolution, even more uses were found for this unique metal. However, by the 20th century, scientists realized that maybe this stuff really wasn't so good for us. Learn more about lead, how it's been used throughout history, and how our perception of it has changed on this episode of Everything Everywhere Daily.

Starting point is 00:00:40 What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night. And how it shaped the world now. Time travel with us. Every week on the ThruLine podcast. from NPR. As I mentioned in several previous episodes, there were seven metals that were known to ancient

Starting point is 00:01:24 people. Gold, silver, tin, iron, copper, mercury, and lead. I've done episodes on all the other metals of antiquity, and this is the episode about the last of the seven metals, lead. So let's start with the basics of lead. Lead sits at the 82nd position on the periodic table with 82 protons in its nucleus. There are four stable isotopes of lead, and lead is often created at the end point of the decay chain of uranium 238, uranium 235, and thorium 232. Lead has the highest atomic number of any stable non-radioactive element.

Starting point is 00:02:04 Lead naturally has a very dull gray color, making it one of the few metals that doesn't have a shiny silver color. One of the attributes of lead you're probably familiar with is its density. lead has a very high density which makes it useful for a host of applications, some of which I'll get to in a bit. Lead also has a relatively low melting point, which makes it easy to work with. Of the seven metals of antiquity, only mercury, which is a liquid at room temperature, and tin have lower melting points. One of the other significant properties of lead is that it doesn't corrode. So with that, the earliest evidence of the human use of lead dates back about 8,500 years. in Anatolia in modern-day Turkey.

Starting point is 00:02:47 Small lead beads have been discovered, which may have been evidence of the earliest human smelting of metal. It's thought that the first attempts at lead extraction really had nothing to do with lead per se. It's just that lead is often found alongside silver, and it may have been that the lead was smelted just to get access to the more attractive silver. However, lead was eventually pursued for its own sake

Starting point is 00:03:10 once its properties were better understood. The first people to probably actually use lead were the ancient Egyptians. They used lead for a host of purposes, including for cosmetics, glazing for pottery, weights for fishing nets, and for ornamental use. Many other cultures independently discovered the properties of lead all around the world. In Mesopotamia, as well as in China, lead was used for simple coins. In the Indus Valley civilization and the civilizations in Mesoamerica, they used lead for simple jewelry and amulets. In eastern and southern Africa, lead was used to create wire, which was actually one of the earliest examples of metal wire making in human history.

Starting point is 00:03:52 The Greeks were the first people to take advantage of the anti-corrosive nature of lead. They would create sheets of lead and use them to line the bottoms of ships. This would not only inhibit the growth of barnacles, but the weight of the lead would serve as a ballast. Another major use of lead was for ammunition for slings. Lead was heavy, and it could be shaped into a more leafful. projectile. And lead was also used occasionally as a medium for writing, as thin sheets of lead could easily be scratched. The people who really took lead usage and lead production to another level were, of course, the Romans. They were far and away the biggest producers and consumers

Starting point is 00:04:30 of lead in the ancient world. In many ways, the Romans used lead in a similar way that we use plastics in the modern world. Lead was very malleable, which made it very easy to shape. One of the biggest uses of lead was in aqueducts and in water pipes. In fact, the Latin word for lead is plumbum, which is where we get the English word for plumbing. And it's also why the chemical symbol for lead is PB. The Romans used lead to line their baths and use lead in cookware. It was well known that cooking food in lead containers would add sweetness to it in the form of sugar of lead, chemically known as lead acetate. The Romans were producing about 80,000 tons of lead per year out of the mines around the empire, although, as with the first users of lead, they primarily got their lead while pursuing silver. After the fall of the Western Roman Empire, lead production around the Mediterranean dropped sharply. The new centers of lead mining were in India and China. In China, lead was used in metal alloys as well as many of the uses I described before.

Starting point is 00:05:35 In India, lead was used in traditional Ayurvedic medicine, and was thought to have therapeutic properties. And, yes, I know what you're thinking when you hear that, and I'll be getting to it in a bit. Back in Europe, around the 10th and 11th centuries, Lead made a comeback. It was used as a major component in the creation of stained glass. Both European and Islamic alchemists thought that lead was simply an impure form of gold. They both had similar properties in terms of density and malleability. And this was why alchemists thought that they could turn lead into gold.

Starting point is 00:06:08 because they simply thought that gold was a purified version of lead. Around this time, firearms came into use, and lead was found to be an ideal projectile. Lead projectiles had a high density, could easily be made with a wood fire, and were deformed on impact causing more damage. Lead was also the base of the pigment known as Venetian seruse. It was a white powder that was used as a cosmetic, as well as in powdered wigs. If you've ever seen an image of Queen Elizabeth I'm wearing white powder all over her face, it's Venetian seruse.

Starting point is 00:06:43 It was also used to powder wigs up until the 18th century. When the printing press was developed, much of the movable type was created using a lead alloy. Lead was also used as the tiles for roofs because of their waterproof and anti-corrosive attributes. Puter, which was an alloy of lead and tin, became popular in the 17th and 18th centuries for use as plates and cups. When the Industrial Revolution began in the 18th century, the demand for lead went up dramatically. It was the first time in centuries that lead production managed to equal the levels that it did during the Roman Empire. Lead was still used for ammunition, and the demand for ammunition only increased as wars became ever larger. Lead continued to be used for plumbing, and demand for pipes increased as running water became more popular.

Starting point is 00:07:31 Lead was also used in many paints as the addition of lead made for more durable paint, that dried faster and resisted moisture. Contrary to popular belief, lead was never used in pencils, even though it's commonly referred to as pencil lead. The name simply comes from the confusion over the color, and some form of graphite has always been used for what people think of as lead. One of the biggest uses of lead was in the creation of lead acid batteries, and today this is still the biggest use of lead in the world.

Starting point is 00:08:03 In 1921, lead was added to gasoline as an anti-knock agent to make cars drive better. So you can see that lead has had a host of uses throughout history in places all over the world. However, there is a giant elephant in the room that I haven't yet mentioned, and I'm guessing that most of you thought it right away the moment you heard the topic of this episode. The fact that lead is toxic. For thousands of years, people all over the world have been consuming lead, directly or indirectly. The Romans used it for plumbing and carrying their water. They also used it as a sweetener. In China, India, and other countries, lead was often administered as a medicine.

Starting point is 00:08:45 Lead was eventually used to make glass in the form of crystalware, which was again used to drink out of. Lead poisoning was something that had been known for a very long time. The Roman architect Vitruvius wrote about the dangers of lead poisoning over 2,000 years ago, and the Romans knew it as Saturnine gout. It wasn't until the 20th century, however, that we realized just how bad lead can be. For starters, there is no known biological need for lead at any level. There are certain elements that are required for human metabolism in very trace amounts, such as selenium and chromium. However, there appears to be zero need for lead. However, the human body can bioaccumulate lead over a lifetime, and it can collect in your bones and organs. Because lead can accumulate, even low

Starting point is 00:09:39 amounts of lead can become lethal over long periods of time. Lead poisoning can cause developmental delays, learning difficulties, and behavioral issues in children, along with neurological symptoms, gastrointestinal problems, and anemia. In adults, it can lead to memory loss, mood disorders, muscle and joint pain, reproductive issues, and hypertension with symptoms varying between acute and chronic exposure. The harms from lead poisoning became so well known and so bad that in 1983, an environmental chemist by the name of Jerome Naragu wrote an academic paper where he proposed that the Roman Empire actually fell due to lead poisoning.

Starting point is 00:10:20 However, his thesis has been roundly rejected by pretty much everyone. The movement to ban lead seriously began with the discovery by Claire Patterson, whose story I told in a previous episode that lead was showing up everywhere in the environment due to its use as a gasoline additive. Over the last several decades, lead has been removed from almost everything. Paint is now almost universally lead-free, as is crystal. That doesn't mean you can't touch lead or that it's as bad as something like mercury, but it does mean that you absolutely should not be ingesting it. Despite the bans and concerns around lead, lead production has actually been going up globally, and today lead production is at an all-time high. About 10 million metric tons of lead

Starting point is 00:11:06 is produced annually, and over half of that actually comes from recycling. The world's largest producers are in order, China, Australia, and the United States. About 80% of all lead produced today is used in lead acid batteries. Lead acid batteries are the type that are used in cars, and the lead is why those batteries are so heavy. Lead acid batteries still. Lead acid batteries still have many advantages, including being rechargeable and relatively cheap. In addition to automobiles are often used in home renewable power setups. The other 20% of global lead production mostly goes towards the creation of glass. High quality glass still uses lead, but it's no longer used for dinnerware. Normally, when I do an episode on an element, I can say that somewhere around you is something

Starting point is 00:11:54 made out of that element. But in the case of lead, that probably isn't the case unless you happen to be in your car right now. That place is lead in a very unique category of material. It's one that used to be more important than it currently is today. And that is all due to the realization of just how dangerous lead is and the decades' long attempt to get the lead out. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Austin Oakden and Cameron Kiefer. I want to thank everyone who supports the show over on Patreon, your support helps make this podcast possible. I'd also like to thank all the members of the Everything Everywhere community who are active on the Facebook group and the Discord server.

Starting point is 00:12:41 If you'd like to join in the discussion, there are links to both in the show notes. And as always, if you leave a review or send me a boostagram, you too can have it read on the show.

Everything Everywhere Daily: History, Science, Geography & More - A History of Lead (Encore)

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