This is such a pointless thing to take umbrage with. Looking at the table showing the levels and picking one of the highest ones from a brand I've heard of: Colgate Total Whitening comes in at 539 ppb of lead. We'll call that 0.539 ppm to make the maths slightly easier, because that's equivalent to μg/g.

Let's say you really load up your toothbrush and use 2ml instead of a pea-sized blob, and assuming a specific gravity of 1.30, that's 2.6g of toothpaste, of which 0.539 μg/g is lead. So you would ingest 2.6g × 0.539μg/g = 1.3936μg of lead if you swallowed all of that toothpaste every time you brushed your teeth.

Apparently young children swallow 0.053-0.3g of toothpaste, so let's go roughly in the middle and say you swallow 0.18g, so 0.18 × 0.539 = 0.097μg of lead. Call that 0.1μg and you brush twice a day, so 0.2μg of lead per day from brushing your teeth. If you use a pea-sized amount, then halve that to 0.1μg.

The EPA's maximum allowable limit of lead in drinking water is 15ppb, but is lowering to 10ppb (ppb = μg/litre) in 2027. So let's say you live somewhere well below that limit and it's 5ppb in your area. You're supposed to drink 1.5 to 2 litres of water a day, so at 5μg/litre that's 7.5 to 10μg of lead per day from drinking water, or 75 to 100 times more than the amount from brushing your teeth.

[–] Jessica@discuss.tchncs.de 1 points 2 days ago

Thank you very much for doing the math! That really does put it into perspective.

I was assuming you would still be absorbing the lead through your gum line and sublingually through the glands under your tongue into your bloodstream even without swallowing any, but that does sound like extremely low quantities.

For me personally, I have ADHD and a bad memory so anything I can do to mitigate exposure to lead to lessen my chance of developing Alzheimer's or Dementia as I get older seemed like an obvious decision especially when the solution is to just get a low abrasion toothpaste that doesn't include these potentially contaminated abrasive materials.