Video: How to fix a leaking pond.
Does the pond leak? Ummmm....possibly a tiny bit. Well, more than a bit...ok, the darn thing leaks like a sieve!
QUESTIONS ANSWERED:
Damit is not plastic. Therefore, there are no microplastics. I wish I had not mentioned plastic, but that is a very common polymer and I mentioned it as an example of a polymer. A polymer is simply a chain of repeating molecules, or "monomers." Cellulose is a polymer of glucose molecules. Starches are also polymers of various molecules such as fructose, maltose, etc. We have many polymers inside our bodies. In other words, just knowing something is a polymer doesn't make it bad, toxic, harmful, etc. However, this also doesn't mean all polymers are safe.
The specific polymer used for Damit is a trade secret, however, it has been closely scrutinized by multiple health and safety authorities. This includes the governmental authorities of Australia, the USA, Europe, and Asia. Not only have they determined that is safe to use in earthen ponds, and not harmful to fish, but it is considered safe to use in human potable water systems in all of these areas. And of course, they know the exact makeup of the polymer when making this determination. I'm told that the same polymer is in use by many municipalities to keep potable water storage tanks leak free. I can't tell you exactly what the polymer is, because I don't know, but given the confidence with which the governmental authorities have authorized its use, I would bet it is made of a monomer that we are exposed to all the time, like fructose or something.
It also breaks down in a matter of years, and does not accumulate in the environment. The end products of breaking down are CO2, water, and base minerals like potassium. The SDS reports no need for concern with ingestion, inhalation, or contact. If in eyes, rinse with water.
End result, can I say for sure that it is 100% safe? No, I don't know exactly what it is. But given people who do know exactly what it is, and have scrutinized it, have approved it for use in human potable water systems, I'm pretty comfortable putting it in an earthen pond.