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Comment by snakeyjake | Hacker News Reader

Monazite isn't common. Well, it's somewhat common but not on beaches. Beach sand is mostly quartz.

Beach sand may or may not be radioactive, but California only requires Prop 65 warnings on things for sale.

The beach isn't for sale.

Sand that is sold in the state of California does come with the warning that it is a carcinogen because regular old silicon dioxide is a carcinogen: https://mcdn.martinmarietta.com/assets/safety-data-sheets/na...

With all things the dose makes the poison, so even if you are a beach bum you're ok but if you are an industrial worker exposed to concentrated amount of silica dust on a daily basis, you should really be informed that it is a carcinogen (among other things) and be equipped with PPE.

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I don't think Silicosis is cancer as much as it's just "shredding your lungs"

It's a horrifying disease and people in affected industries should always wear PPE and likely don't.

Silicosis causes cancer the same way a lot of things do: If you repeatedly damage cells over and over and over, that increases the likelihood that some of the DNA will be mis-copied, fail to be repaired, and survives the biological lottery to become a cancer cell.

> Beach sand may or may not be radioactive, but California only requires Prop 65 warnings on things for sale.

They're not just on things for sale. They're also required at workspaces, businesses, rental housing. I've seen them on unpaid parking structures.

If the beach was operated by a private entity instead of by public agencies or just public access with no supervision, a warning might be needed.

I'm not a geologist; did I misunderstand the Wikipedia entry I linked? It says

- "Because of their high density, monazite minerals concentrate in alluvial sands when released by the weathering of pegmatites. These so-called placer deposits are often beach or fossil beach sands..."

And I found two specific examples of notably radioactive monazite beaches—an 800 km stretch of Brazil's coast [0], and 55 km stretch of India's coast [1].

[0] https://en.wikipedia.org/wiki/Guarapari#Radioactivity

[1] https://www.thehindu.com/sci-tech/No-major-birth-defects-fou...

Those locations, with their high concentrations ("high" being "greater than 0.01%-ish") of heavy metals, of which mazanite is but one of many, are the rare exception.

The IAEA report on Guarapari specifically says "it's weirdly high, brah":

>The exposure level due to monazite sand radiation in Areia Preta beach, Guarapari, is high. The activity concentration of 232Th in Areia Preta is higher than others beaches in world studied. The values of the absorbed dose rate in air and outdoor annual effective dose rate in Areia Preta beach are higher than the world averages due the content of 232Th. Areia Preta is also has higher background found in beaches in world.

https://inis.iaea.org/collection/NCLCollectionStore/_Public/...

Depends on the beach. Brasil has more than others.

https://www.youtube.com/watch?v=vdHHUGwFoJE

There are other radioactive types of sands. Black sands ( https://en.wikipedia.org/wiki/Black_sand ) can be quite active, and they can be found in many places.

Wherever the car break runoffs from the highways reach the beach, the chancer rates must be through the roof too

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