30 December 2007

Lead Acetate

This blog is named after a chemical that was once called "sugar of lead" and is sweet tasting but ultimately deadly. It is made up of one atom of lead with an charge of +2 and two acetate groups.

When this is hydrated with water, it forms a white crystal. With this form and its sweet taste its easy to see how this would be called sugar of lead. As with any lead compound, its poisionous to most every living thing since the lead atom will displace the metal ions that are normally used in enzymes. Solid pure lead is not as dangerous as lead compounds since the compounds are more soluble. This is true for lead and for mercury; pure mercury can lead to acute poisoning, but organic mercury compounds such as dimethyl mercury are insanely deadly. While mercury is more toxic in lower doses, the paralells are true.

In a comparison of the bioactivity of different lead compounds, lead acetate and lead oxide lead to higher lead levels in the bones of rats. Comparison of lead bioavailability....

Lead acetate was made by the Romans when they boiled wine in vessels that were either lined with lead or had lead in the bronze. This would cause the acetic acid in the wine to react with the metallic lead, this would sweeten the resulting defrutum. This probably also contributed to the relatively high intake of lead that the Romans had.

As I mentioned earlier this week, lead acetate is still around. Its found in some hair dyes. Useless Information tells us here how the small concentration lead acetate reacts with sulfur also in the dye to create a black pigment. The lead will still be present in the hair even after the dye is no longer used. Our government has decided that the level of lead acetate in these hair dyes is low enough to not pose a risk. How much using this lead acetate product would add to your overall life time lead exposure is unclear. I for one wouldn't want to actively add more lead to my life.

Why did my name my science leaning current events blog after a strange lead compound? To be honest I just thought the story about the Roman's sweet boiled wine was neat. One could make an analogy about something being sweet but deadly or tasty in the short term but poisonous and debilitating in the longterm, but I'll leave that to those better at such things.

References: Wikipedia and Molecule of the Day were both very useful.

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