Present technical terminology seems to be that all copper alloys are called "bronze" and the main alloy is mentioned: tin bronze, zinc bronze, aluminium bronze ... That is still not the common usage though.
I understand that historically many a "bronze" was actually a "brass" meaning it was mainly a alloyed with zinc. Some of the resident archaeologists could comment. The polished colour of the metal tells a lot of the content.
Salt does not affect the pH of water all that much but it does cause corrosion via various electrolytic processes. Zinc in brass does pretty much prevent the copper from leaching as long as there is enough of it around, once it is gone the copper starts to solve, the rate depends on a lot of things. Tin passivates fairly well and so protects the underlying copper. Locally here the story is that untinned or broken-tinned pot starts to be poisonous fairly soon. Copper was last used on coffee pots and remember grandmother checking the tin lining every so often. I don't remember having heard of tin poisoning from pots but a lot of stories about copper one.
Copper is used still for water piping so it can't be all that big a problem, on the other hand I have seen recommendatios that hot tap water should not be used for drinking (too often, I guess). I have not seen actual analyses of water in various vessels or piping what the true copper content would be.
