Examples of lead. (Copyright © Alchemist-hp. Shared under Free Art License 1.3

Probably its most recent widespread use, i.e., in all communities and at all societal levels, was as an additive in petrol. Lead was finally removed from UK petrol only in 1998. Lead is most effectively absorbed across a moist membrane, such as across the lining of the mouth, throat, lungs and gut. Burning petrol and then pumping the exhaust gases into the air, whether in town centres or the countryside, is an effective way of distributing lead particulates and getting them into people's eyes and lungs.

So what does lead do to the body? 

The problem for humans and many other animals is that lead is easily absorbed, particularly when we've turned into powders and liquids. It can also be absorbed through meats and vegetable that have already absorbed it, i.e., if those animals and plants were already poisoned by lead. This is known as organic lead, and is more dangerous as it more readily taken up by biological processes.

It can accumulate over time, distributing itself in the body in preference to the regular, beneficial chemicals, causing gradual failure of biological systems, or it can be absorbed in a sudden hit, producing a kind of chemical shock. When cells manufacture proteins, lead replaces the correct metals, distorting the proteins and rendering them useless. In the brain, lead replaces the calcium ions so necessary for generating impulses, causing diminished recall. It's bad enough in adults, but it's a major concern in children's development, as this is a period of increased growth and specialisation. Exposure at this point can result in deformities and defects which likely won't repair. Since lead isn't used in human biological processes, there is no safe level, just avoidance.

So there's your daily dose of doom and gloom. The take-home points are, A) go easy with your cremnitz white and B) don't lick your antique oil paintings.

Front page image by Wikipedia contributor Sb2s3, used under CC BY-SA 4.0 licence.