Think of the ground beneath your feet as a giant, grumpy kitchen sponge. It holds onto water, but it also soaks up minerals and rocks that touch it. Arsenic is a naturally occurring element in the Earth’s crust, like the baking soda hiding in the back of your pantry—except you don’t want it in your cake.
When rainwater falls, it percolates through soil and bedrock, slowly dissolving tiny bits of arsenic from rocks like a lazy tea bag steeping in a mug. This process has been happening for millions of years, long before humans started worrying about water filters.
So, the first way arsenic gets in water is just Mother Nature doing her thing. She’s not trying to poison you; she’s just recycling minerals, like that friend who never throws anything away.
