Plants exposed to treated lumber and black walnuts safe?

Hey I've got some hornwort growing in a tub in the yard. I'd like to know if it's safe to use since there is some treated lumber in the tub and some black walnut leaves as well.

Is it safe to use in an aquarium with fish, shrimp, and snails?

The lumber is the part I'd worry about with shrimp and snails. Pressure treated wood from the last twenty years or so uses copper based preservatives (older stuff is CCA, copper plus arsenic), and hornwort is very good at soaking up copper. It gets used in studies on pulling metals out of ponds.

Rinsing won't get out what's in the leaves. I'd grow a few sprigs on in a clean bucket for a few weeks and only use the new growth.

Thanks, sounds like it's not a good idea.