I confess, a primary reason that I started the Round Down US project is reports that the new zinc pennies are toxic.
The United States Mint switched from copper pennies to a copper coated zinc mix in 1983. When the copper coat gets breached the the zinc can leach out and cause Zinc Toxicity. Zinc toxicity can cause illness in children and is fatal to dogs and parrots.
Apparently there also problems with plants and fish when they become exposed to concentrated zinc from a dissolving penny.
I've noticed that zinc new pennies, when damaged, turn sharp and ugly. When they sit in the dirt for years, they start to dissolve.
I often find worn zinc pennies in playgrounds and gutters. As so many people just toss out pennies, it is absurd to be using them.
The mint is reworking the composition of coins. Instead of the people being led by the government, I would rather the people lead the way and round down first.