History and science have always interested me for the same reason: these subjects explain why things are the way they are. They just explain different types of things. Sometimes they’re more intricately connected than one might expect. Chemistry is connected to many minor historical events, for example the fall of the Roman Empire. Yes!
Lead has the chemical symbol Pb and the atomic number 82 on the Periodic Table. It’s atomic mass is 207.2 and it melts at 621.5°F (327.5°C), which is relatively low for a metal (compared to gold (Au) which melts at 1,948°F (1,064°C)). It’s classified as a heavy metal. Some of the common effects of lead poisoning, many of which are common to all types of heavy metal poisoning, include the appetite loss, abdominal pain, colic, pallor, weight loss, depression, fatigue, irritability, and nervous spasms. Also, eventually you’ll go crazy because it affects the nervous system. It’s not fully understood by what mechanism heavy metals affect the nervous system, but it may have something to do with the enzymes responsible for distributing important minerals throughout the body, such as Calcium and Selenium (1). So, you can see why consuming this type toxin could be disruptive to a society.
Our love of lead began a long, long time ago. It was one of the easiest metals to work with and extract from natural ore because of its low melting point and abundance in the earth’s crust. The oldest known lead object is from Turkey (circa 6,500 B.C.), and pottery from Ancient Egypt (3,000-4,000 B.C.) has been found glazed with lead. Lead has been used for everything from furniture decorations to stained glass window frames in churches and cathedrals. Its use has had endless repercussions on history, so I’ll touch on the highlights.
Lead (II) Acetate, chemical formula Pb(CH3COO)2, also known as “sugar of lead” was used by the Ancient Romans as a sweetener for food and beverages, particularly wine (2). That was long before anyone was sailing over to the Americas and bringing back cane sugar. As if running your drinking water through lead pipes wasn’t enough, they went right ahead and added the stuff directly to their diet, sometimes even sprinkling the crystals on dishes like a spice. Good plan.
Lead compounds were also commonplace in colonial times:
During the Colonial Period, in addition to the trade in rum, there was extensive manufacture and use of glazed earthenware, pewter, lead pipe, lead shot, and lead type for printing. Red and white lead were widely used as pigments for paints (also as an addition to red pepper); lead acetate and lead oxide were used to sweeten and whiten bread. Litharge (a PbO product) was used as a putty to install windows and, according to colonial records, was sometimes added to snuff. Apparently, lead intoxication was rampant during the Colonial Period in America and may have been involved in accusations of witchcraft because individuals with lead poisoning neu- ropathy often show weird behavior (3).
People long suspected that lead had negative effects on health, based on their observations of those who worked directly with it, such as miners or potters. Yet, time and time again, despite the difficulties of Roman emperors (notably Julius Cesear and his successor, Caesar Augustus) had producing children, the observations of Greek physicians, the warnings of Benjamin Franklin and even the U.S. government, people continued to use it in all sorts of self-destructive ways. In 1473, a publication entitled “On the Poisonous and Noxious Vapors and Fumes of Metals” was authored by U. Ellenberg, but the United States Congress waited until 1970 to pass the Occuptational Health Act to regulate lead in food packaging and the environment.
I was shocked to learn that leaded fuel was available until the 1990′s, and that a 1980 report from the National Academy of Sciences estimated that Americans were using about 11 pounds of lead per person each year. The General Motors engineers who developed the leaded fuel met the same fate that many exposed to lead had met before,
As many as fifteen workers who helped produce the additive in refineries in Ohio and New Jersey fell sick and died. In most cases, mental derangement preceded death, and many of the workers died in straightjackets. Nearly 300 workers from three plants were pronounced psychotic, and workers and journalists soon began to call leaded fuel “loony gas.” For the next six decades, as many as 5,000 Americans died every year from lead poisoning, according to a 1995 EPA report (4).
I had no idea that lead use was and is such a big deal. Some researchers estimate that 7 million tons of lead from burnt gasoline remain in the United States ecosystem. But, hey, at least we’re not using it as a condiment anymore.
More information about lead and the environment can be found here. And the links in the sources are also worth checking out.