name 4 possible ions or molecules that could also be present in tap water?

Question

i already have copper (from old piping) so i need more answers. plz and thx.

Answer 1

water itself, of course.
The following ions.....
iron ions, calcium ions, sodium ions, chloride ions, fluoride ions...

oxygen molecules, carbon dioxide molecules, sometimes around here hydrogen sulfide molecules.

ALMOST EVERYTHING is in water in minute concentrations.

Answer 2

Just about anything can be present.

Chlorine is a common additive to kill bacteria.
Fluoride is naturally present in some water, and is added in some other areas to strengthen teeth.

I attach a website that has actual contaminant levels for all the states.