F. George McDuffee wrote:
snip

Not a good idea. As the copper is slowly consumed (rusts), a portion of the
effluent would be Cupric Chloride and/or Copper Sulphate, which are extremely
toxic to living organisms.

snip
Which is why they used it. Killed the barnacles, ship worms,
etc. Kept the ships bottoms relatively clean.

Uncle George

Its mean stuff

I've had cupric sulphate on my arm at an old abandoned turn of the
century mine. Itches worse than fiberglass insulation

Looks really beautiful when you see a pond of it makes the water look
bluer than blue and still clear. (then i found out what it was AFTER)

Brent
(Raised in a mining town where the ores had large amounts of Sulphur
along witht he copper and nickel)