Why I'm not using Black Diamond Blasting Sand (BDBS) in my Aquarium. After a bit of a deep dive.

TLDR: BSBS is an industrial byproduct. It has 1000x more beryllium (a carcinogen) in it than normally found in soil. However, some choose to use it because the beryllium is bound in the slag crystals.

First of all, I love the look and the price. But when I saw that it was referred to as coal slag on the bag, I decided to do a bit of research into what that was.

Coal slag is what is leftover when coal is burned in powerplants at 2,000+ degrees. The coal melts/burns and the unburnables condense as various oxides, such as silicon dioxide, glass.

This is interesting, and sounds fine, until you run across the one issue, this process condenses a carcinogenic element found in trace amounts in the Earth's crust, beryllium. At very small doses, we are normally not exposed to beryllium in amounts to be dangerous. However, when people use coal slag to sand blast, the resultant shattering of the slag crystals releases dangerous amounts of dust which contain both beryllium and chrysotile, white asbestos, into the air. To use coal slag as a sand blast protective gear must be worn, including respirators.

Beryllium is normally found around .5 to 2 ppm in the soil in the united states. I'm going to guess this is how much of it shows up in coal too. However, when you burn coal, most of your mass is being burnt, so what remains as slag is condensed. Beryllium accounts for around .05% of coal slags mass. Still a very small amount, but 1000x what we are normally exposed.

But, no prob, right, we aren't sand blasting, we are just putting it into our aquarium and it should be inert right?

Probably, however, there are still two concerns. One is opening the bag and pouring it into a bucket to rinse will expose you to some amount of coal slag dust. Two, beryllium slowly moves into organic tissues it is in contact with. This is why inhalation is so bad, if you eat it you will absorb a relatively small amount before it leaves your system. However, inhalation results in it just staying in your lungs until it's absorbed.

So... basically, personally, that just doesn't sit right with me. It's a cool product and a cool idea, but I don't like the potential problems of something like this when something natural exists for only slightly more money.