| You have mercury all wrong, and lead mostly so. Elemental mercury is very difficult to absorb, and even in vapor form the LD50 is quite high. It typically requires extended exposure to even vapor from mercury to have any issues. Even a drop of organic mercury on a glove (let alone skin) can kill. Historically, even periodically drinking liquid elemental mercury was relatively harmless and didn’t poison anyone. You’d have to do it a lot. The Louis and Clark expedition used it for its laxative effects, and it’s allowed historians to confirm which campsites were theirs or not, for instance. Most compounds and salts of mercury, especially organic compounds, are incredibly toxic. [https://emergency.cdc.gov/agent/mercury/mercorgcasedef.asp] Many of those compounds form when metallic/elemental mercury is around certain microorganisms, like those in many ponds and lakes, or when man made. Lead isn’t dissimilar. Lead poisoning (or measurable uptake) from elemental lead almost always requires extended ingestion or inhalation of lead, or ingestion/exposure to a salt or compound which allows easier intake. The most common forms of lead poisoning usually involve things like habitual smoking or eating while having lead dust covered hands, or persistent ingestion of lead containing substances (like contaminated water) or breathing in of lead contaminated dust. It takes a surprising amount of persistent exposure, unless someone is really stupid. Like doing oxyacetylene cutting of lead sheet without PPE, or cleaning a shooting range then not washing their hands after. |