But what about the zinc? Also safe levels?

"BW" == Brian Whatcott writes:

BW News of a water storage tank that is bactericidal - e.g. to E.Coli
BW within 48 hours: brass!
BW British researchers joined with Punjab U researchers to check the
BW supposition that the Indian tradition of carrying water in mutkas
BW (brass pots) was beneficial - which confirmed the suspicion, given a
BW dwell time of 48 hours plus.

BW The action stems from a low copper leaching rate out of the container.
BW The copper level in the water is extremely low and safe - in fact,
BW only a fraction of the recommended intake.

BW [New Scientist, 9 April 2005, p.14]

BW Brian Whatcott Altus OK

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C++: The power, elegance and simplicity of a hand grenade.