Lead, a dense, malleable metal is good for many things. The reason lead was (is) so prevalent in our society is due to its many desirable characteristics. In short, lead is a wonder of nature with many practical uses. It’s abundant and easily shaped. It has a low melting point, requiring less energy to mold. It is resistant to corrosion. Lead makes paints adhere to walls better and gasoline resist knocking. Lead was exactly what was needed for the printing press to take off and for firearms to achieve their deadly potential. Most of the lead used today is in lead acid car batteries, where recycling and proper disposal is tightly regulated.
Lead is toxic to humans and animals. Its negative health effects have been known since the Industrial Revolution, and some even claim nearly 1,700 years earlier. Lead exposure has detrimental effects on child brain development. The adverse effect of lead on child development has been known for 80 years:
Since 1943, scientists have known that lead can have adverse effects on neurological development in children, leading to behavioral problems and lowered intelligence. That’s because it can easily replace calcium. Calcium is how neurons in the brain communicate, and if lead replaces it, there is either too little communication among neurons, or too much. This can cause erratic mood swings, or difficulty processing information, for instance.
From the late 1960s into the late 1970s, officials began trying to get lead out of the environment. According to NPR:
American blood lead levels have plummeted more than 90 percent in recent decades. In the late ’70s, almost 9 out of 10 American children were walking around with high lead levels. By 2008, it was closer to 1 in 100.
Lead has been removed from paint, much to the chagrin of homeowners who must repaint far more often. Lead was removed from gasoline long ago, raising the cost of driving a car. The only fuel that still contains lead is aviation gasoline (AVGAS 100LL). The EPA and the FAA are currently trying to phase it out too.
Ancient Romans loved lead. It was used to line coffins, make cooking pots and eating utensils. It was used to line aqueducts and water pipes in cities. When I was in Pompeii we were shown lead pipes and told the Romans were well aware of the toxicity of lead. Supposedly they believed that over time calcium would form a layer lining the inside of the pipes, making the water safe to drink. That is probably wrong. Roman even used lead to cook and sweeten foods in a time when sugar was unknown and honey was super expensive.
They did have an abundance of grapes, and used to boil down the juice in their lead pots. Lead ions would leach into the juice and combine with the acetate from the grapes. The resulting syrup was very sweet and used in wines and a wide variety of foods. In fact, of the 450 recipes in a cookbook from that era (the Apicius cookbook), 100 called for those syrups.
About 40 years ago scholars began to speculate that lead poisoning contributed to the fall of the Roman Empire.
[A] 1983 paper in the New England Journal of Medicine by Jerome Nriagu, who was studying the diets of Roman emperors between 30 BC and 220 AD. Nriagu noted that 19 of the 30 emperors showed a preference for “lead-tainted” food and wine, concluding many likely suffered from gout and lead-poisoning as a result.
The debate about the role of lead in the fall of the Roman Empire is ongoing. Some of the Roman-era bones that have been analyzed show 400 times the lead that was found in pre-Roman Iron-Age bones. French researchers studied how lead pipes could leach lead into the water and estimated lead concentrations up to 100 times those found in spring water at the time. Lead still has numerous uses but its toxicity limits its use to products that stand less chance to seep into the environment.