There are residual metals in almost all (if not ALL) fertilizers. Its just the nature of the beast. Nothing that you should be worried about IMO.
I've been using a natural fertilizer by Happy Frog brand and it seems to be working great. It has added bacterias that helps break down organic matter into plant usable substances and so far I've seen very good results. I think you would be fine using that product you have there.
I've been using a natural fertilizer by Happy Frog brand and it seems to be working great. It has added bacterias that helps break down organic matter into plant usable substances and so far I've seen very good results. I think you would be fine using that product you have there.