Not fecal bacteria, though. For Escherichia coli, it injures them to slow down their growth, but they are still viable and will grow again when the inhibitor is removed (such as getting into your body). For other fecal bacteria such as Enterococcus faecalis and Staphylococcus aureus, copper doesn't kill them at all. This post shows kill times for chlorine vs. copper and silver. Part of the reason that fecal bacteria survive in the copper levels when using copper algaecide in pools is that blood serum contains 0.7 to 1.5 ppm copper ions.