The world is terrifying. And it is always trying to kill us. A great example (out of so many) is rabies, which we've talked about before. Horrifying stuff, and if not vaccinated against, deadly every time. Another example is lead. It's everywhere on our little blue dot, and exposure can cause all kinds of issues.
Today we mostly think about lead exposure when it comes to children putting things into their mouths that have lead in them. But as I said, lead is everywhere on the planet and before we understood how dangerous it was, it was in everything. Paint, for example. Lead was added to paint to "speed up drying, increase durability, maintain the color, and resist moisture". Humanity has been using lead in paints for centuries. In the 4th Century BC, earthenware pots painted with lead were fired in kilns and workers often suffered "apoplexy, epilepsy, and paralysis" from working with lead. In 1786, Benjamin Franklin wrote a letter "warning a friend about the hazards of lead and lead paint, which he considered well-established". Lead, particularly lead white, was widely used by artists until the 19th century. Since the middle of the 20th century, many countries have banned the use of lead in paints and many other products. But other countries, like India, didn't ban its use until VERY recently - 2016 to be exact.
Houses built in the US before 1978 (the year lead-based paints were banned in the country) were filled with lead. When the paint peels or cracks, it makes lead paint chips and dust. Even breathing in the dust can cause health issues, but children who are exposed often show no signs at first. It's a little like rabies in that way - no symptoms or maybe some mild ones like headaches and fatigue. Which could be mistaken for a simple cold. But long-term exposure to lead is deadly. In children, it can cause behavioral problems, learning difficulties, lowered IQ, hyperactivity, growth delays, and hearing problems. In adults, it can cause hypertension, kidney problems, and fertility/reproductive issues. And the effects of lead exposure aren't reversible.
Staying exposed to high levels of lead can ultimately cause seizures, unconsciousness, and death.
And paint isn't the only thing that is dangerous! Soil, pottery, toys, cosmetics, certain herbal and folk remedies, Mexican candy, lead bullets, and even working in certain occupations (auto repair, mining, pipe fitting, battery manufacturing, construction) come with an increased risk of lead exposure There are, of course, protective measures to take, like filtered masks and goggles. But lead is in everything.
And the reason we know that is because of a man named Clair Patterson.
Born in Iowa on June 2, 1922, Clair showed a curiosity about the world around him early on. This curiosity was encouraged by his parents, and combined with a sharp mind, Patterson pursued as much schooling as he could. He graduated from high school at 16, and 4 years later earned a degree in chemistry from Grinnell College. He and his future wife, Lorna, both then attended the University of Iowa, where Patterson earned a Master's degree in molecular spectroscopy.
Molecular spectroscopy is the measurement of interactions between electromagnetic waves and matter. The scattering of the sunlight produces a colorful spectrum when a narrow beam of light is passed through a triangular glass prism. This visible light is simply a part of the whole spectrum of electromagnetic radiation, extending from radio waves to cosmic rays. A spectrum comprising the different electromagnetic radiations according to energy, frequency, or wavelength is called an electromagnetic spectrum. Generally, electromagnetic radiations are classified as radio waves; microwaves; infrared, visible, and ultraviolet light waves; X-rays; and gamma rays (Table 3.1). Electromagnetic waves are transverse waves that travel at the speed of light and involve oscillating electric and magnetic fields at right angles to each other.
And then he and Lorna were sent to both work on the Manhattan Project, first at the University of Chicago, and then in Tennessee. Patterson's introduction to mass spectrometry would change the course of his studies, and ultimately change the world.
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.
While Lorna took a research job as an infrared spectroscopist to support Clair during his PhD, Patterson made several early discoveries. Initially, he worked with his advisor Harrison Brown and a lab partner named George Tilton. They were working on geological aging of zircons. Zircon is used in dating because when they're formed "they possess tiny imperfections of uranium but no lead. Therefore, if any lead is present in the zircon, it must come from the decay of uranium." It's now known as U-Pb dating. At the time, Patterson and Tilton were trying to figure out the composition of primordial lead in the Earth; doing so would make it "possible to figure out the age of the solar system, and in turn, the Earth, by using the same techniques on meterorites".
This work began in 1948, just a few years after the end of WWII. But Patterson's end of the research was being delayed - his lead samples were contaminated. It made no sense. They knew the age of the rock from which the zircon came, and Tilton's measurements seemed to be in line. Patterson was baffled, but like any good scientist, he wanted to know why. After six years, after earning his PhD, he and Tilton were no closer to determining the age of the Earth or understanding why his lead samples were contaminated.
In 1953, Harrison Brown brought Patterson to CalTech so they could work on a commission for a new mass spectrometer and Patterson could build his own lab from scratch. Here's part of this guy's genius - he secured all points of entry for air and other contaminants; acid cleaned all lab apparatuses and even distilled all of his chemicals shipped to him. Patterson, by nature of his desire to solve a scientific problem, created one of the world's first clean rooms. And it worked. He was able to continue work on what was known as the Canyon Diablo meteorite and get uncontaiminated lead samples.
In 1956, Patterson published "Age of Meteorites and the Earth", the first paper containing the true age of the solar system. Before this, it was widely accepted that the Earth was roughly 3.3 billion years old. We now know it is 4.543 billion years.
But this discovery - massive as it was - wasn't the only thing Patterson discovered. While refining his paper on the Canyon Diablo meteorite, he was also finding lead everywhere. And Patterson was quickly realizing the dangers of lead.
Lead, The Silent Killer
In 1965, Patterson published a paper titled, "Contaminated and Natural Lead Environments of Man'' in an attempt to draw public attention to the problem of increased lead levels, both in the environment and in the food chain. The paper didn't have the immediate effect he was hoping for; in fact, it drew ire from other scientists, ones who were recognized as experts in fields like food production, industrialization, and the infamous gasoline companies. Possibly Patterson's biggest critic was a man named Robert A. Kehoe, an American toxicologist who worked on behalf of the lead industry, including the manufacturing of leaded gasoline and lead-acid batteries.
Kehoe was definitely what we would call a bad scientist, driven by money and power over the advancement of scientific discoveries and the health and well-being of his fellow humans. Kehoe even claimed that the "presence of lead in humans and other organisms was normal and that exposure to low lead levels was not harmful." The "Kehoe Rule" or "Kehoe Paradigm" came out of his testimony at a conference in 1925
"Kehoe offered (speaking on behalf of the companies engaged in the Ethyl Gasoline enterprise) to discontinue the sale of gasoline containing lead "if it can be shown ... that an actual danger is had as a result..." But, he reasoned, if it could not be shown "on the basis of facts," a product this economically beneficial should not be "thrown into the discard on the basis of opinions." Kehoe's offer thus acted as a decision rule (hence, "the Kehoe Rule"), setting out a choice point and two alternative paths that could be followed, depending on what was shown as proof at that choice point." The rule essentially became a Schrodinger's Cat issue, allowing Kehoe to sidestep any immediate concerns about lead in gasoline by saying there could be an issue, but there was no evidence in the immediate to support such a claim. His lab, which was then charged with finding, if any, health effects from lead exposure, was able to control the research and dominate that realm of science for decades, allowing gasoline companies to continue using lead.
Patterson was Kehoe's biggest naysayer, especially because he noted that global lead contamination was taking place and that it "had started gradually with the Industrial Revolution but had been markedly accelerated once leaded gasoline had entered the market." Directly in conflict with Kehoe's aggressive assertions and, of course, the source of his income. The power of these industries was so strong that Patterson was refused contracts with many research organizations, including the supposedly neutral United States Public Health Service. In 1971, Patterson was excluded from a NRC (National Research Council) panel on atmospheric lead conditions, even though he was the then foremost expert on the subject.
Blind greed and lobbying in science leads to drastic consequences.
Eventually Patterson's efforts did pay off. The 1970 Clean Air Act and a global effort to remove lead from gasoline and other products grew out of his work and increased public awareness. It's impossible to know exactly the impact of Patterson's work on global health, but there continues to be compelling evidence, like how the rise in violent crime in the US in the 1960s and 1970s (and its decline in the 1990s) can be tied to lead's prevalence in the atmosphere. The article in Mother Jones, "Lead: America's Real Criminal Element" is a fascinating read but the author's conclusions make it pretty clear that lead "may explain as much as 90 percent of the rise and fall of violent crime over the past half century."
"The biggest source of lead in the postwar era, it turns out, wasn't paint. It was leaded gasoline. And if you chart the rise and fall of atmospheric lead caused by the rise and fall of leaded gasoline consumption, you get a pretty simple upside-down U: Lead emissions from tailpipes rose steadily from the early '40s through the early '70s, nearly quadrupling over that period. Then, as unleaded gasoline began to replace leaded gasoline, emissions plummeted. Intriguingly, violent crime rates followed the same upside-down U pattern. The only thing different was the time period: Crime rates rose dramatically in the '60s through the '80s, and then began dropping steadily starting in the early '90s. The two curves looked eerily identical, but were offset by about 20 years....digging up detailed data on lead emissions and crime rates to see if the similarity of the curves was as good as it seemed. It turned out to be even better:...[a] 2000 paper...concluded that if you add a lag time of 23 years, lead emissions from automobiles explain 90 percent of the variation in violent crime in America. Toddlers who ingested high levels of lead in the '40s and '50s really were more likely to become violent criminals in the '60s, '70s, and '80s."
Conclusion? "When the differences of atmospheric lead density between big and small cities largely went away, so did the difference in murder rates." And, "high childhood [lead] exposure damages a part of the brain linked to aggression control. The impact is greater among boys."
Despite the gasoline industry's best efforts to defund Patterson completely, he did receive support from the US government, a few branches of the Armed Forces, and the National Science Foundation, to name a few. This increase in research funds let Patterson take a team to Greenland to study the ice sheets, under the theory that if lead accumulated in our oceans, it must accumulate in ice as well. Working with ice cores, he was able to study how much lead was present in past centuries. His conclusion: that before the introduction of tetraethyl lead, there was almost no lead in the atmosphere. We created this problem.
"In 1979, Patterson conducted an analysis of 1600 year-old bones from Peruvian Indians, and he discovered that they held a vastly smaller amount of lead than the bones of modern-day humans. Patterson used his lab at Caltech to measure the amount of lead in canned tuna. Other labs had shown that there was no difference in the amounts of lead in canned tuna and fresh tuna; however, Patterson was able to find that there was a thousand-fold difference in amounts of lead in fresh tuna than in canned tuna. This find would be able to be applied to all fresh and canned fish, thus showing that lead should not be used in commercial products."
Patterson's work has had massive impacts, even decades later. It's too bad we didn't ban lead in gasoline and other products earlier. Our cars are lead free today, but all that lead spewed into the atmosphere had to go somewhere. A lot of it wound up in our soil. And as subsequent studies have shown, even miniscule amounts of lead are linked to attention deficit/hyperactivity disorder. Children now may be affected by what was spewed out of tailpipes in the US for 50+ years. There have been suggestions that the rise of aggression and decrease in critical thinking skills and IQ in Boomers and Gen Xers could be tied to lead exposure from their childhoods.
"Researchers found that estimated lead-linked deficits were greatest for people born between 1966 and 1970, a population of about 20.8 million people, which experienced an average deficit of 5.9 IQ points per person."
"One study based out of Cincinnati, Ohio in 2001, for instance, found that young adults who had high exposures to lead as children were more likely to display psychological traits that included impulsivity and egocentricity-traits that ultimately impact a person's ability to regulate their emotions."
We're still understanding the impacts of Patterson's work, and the fight to regulate chemicals is ongoing. But without Clair Patterson, we can't begin to calculate what might have happened with more lead in our air, water, and soil.
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