I tested one of my bowls which was empty in my coop until it rained today and it caught about an inch of water.
The video is linked here.
I used standard well water test strips and got a reading of 30 mg/L. Per the EPA the Alert Level is 0.015 mg/L.
My results were 2000 Times the EPA Limit.
I encourage you to do your own testing and report the results. I would also encourage you not to use these bowls for watering any of your animals.
Please share this info, and I can't believe these items are being sold almost everywhere.