<unk>  and its alloys (brasses, bronzes, cupronickel,<unk> -nickel-zinc, and others) are natural<unk>  materials. Ancient civilizations exploited the<unk>  long before the concept of microbes became understood in the nineteenth century. In addition to several<unk>  medicinal preparations, it was also observed centuries ago that water contained in<unk>  vessels or transported in<unk>  conveyance systems was of better quality (i.e., no or little visible slime or biofouling formation) than water contained or transported in other materials. The<unk>  are still under active investigation. Molecular mechanisms responsible for the antibacterial action of<unk>  have been a subject of intensive research. Scientists are also actively demonstrating the intrinsic efficacy of<unk>  alloy "touch surfaces" to destroy a wide range of microorganisms that threaten public health.
Antimicrobial properties of copper
Iron metallic discoloration
Titanium metallic discoloration
Toxic heavy metal
Cold sensitive antibodies
Pathogenic fungus
Persistent, bioaccumulative and toxic substances
Respiratory pigment