Science! // Let’s Talk About… Lead in Cosmetics, Part 1

I’ve been wanting to write this post for a while, but it’s definitely a time-consuming post. The truth is that there just isn’t a lot of information out for the general public when it comes to heavy metals and cosmetic safety. This is going to be a three part series, and Part 1 (today’s post) is going to focus on the first question: what is lead?

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Why is this such an important question? We can talk about levels of an item all we want, but that doesn’t make it dangerous. If I told you that your foundation was 50% dihydrogen monoxide, some of you might scratch your head, some might get a little worried, and of course some of you who know chemical names would roll your eyes at me. This is just the chemical name for water, and if you have a foundation that is half water, it wouldn’t be inherently dangerous, right? Understanding what lead is allows us to understand the consequences of lead exposure

So, let’s begin: what is lead?

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  • Lead is a metal. For those of you who paid attention in chemistry class, you can probably skip this. For those who didn’t (or just never got the opportunity): a metal is a type of element with some distinctive properties. They are usually solids at room temperature, are malleable (meaning we can shape them, such as the old smiths shaping metal into swords), and conduct electricity, although lead is actually a poor conductor. They also tend to easily form what is called a cation (pronounced cat-eye-on), which essentially means when they come into contact with other elements, they like to become positive in charge.
  • In fact, it has a common oxidation state of +2. Which means it most readily forms a cation with a charge of positive two (it wants to “give away” two of it’s circling electrons). For those who don’t have a chemistry background, this isn’t super important- it just tells us some information about how it will react.
  • Lead is a heavy metal. No, I’m not talking about music!! This means that each atom of lead has a relatively high mass. Heavy metals are often defined as having a density at least five times greater than water- which means that you can fit 5 times as much mass of the metal in the same size. One way to think about this: 1 milliliter of a heavy metal weighs the same as at least 5 milliliters of water.
  • Lead has many historical uses. Several hundred years ago, lead was, in fact, used in pencils (now, what you call “lead” in pencils is actually a mix of clay and graphite). It’s a very soft metal, so it was often used in forging to make pewter (tin and lead), although now we use other soft metals. Plumbing (pipes) were also often mead of lead. Today, lead is found mostly in batteries and protective gear for x-rays and other forms of radiation. Lead has also been historically used in some paints- which is something we will talk about!
  • But, in the body, it has no true uses. Some heavy metals, like iron, are necessary for our survival. Lead has no purpose in our bodies, and in fact can cause severe damage- which is what we will talk about in Part 2.

It’s important to note that we are exposed to lead frequently. Given it’s typical stability and historical use, lead is everywhere! Lead additives were common in gasoline (ever wonder what “unleaded” gas was?), which polluted the air with lead. Old houses still have heavily leaded paint on their walls, and many cities still have lead pipes (it’s not just in Flint!).

Next week, I’ll talk about what lead does in the human body and how it acts as a toxin, so we can determine what risks lead can pose in our cosmetics (hint: it’s a lot).

Stay curious,
Lucy

 

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