One must think about a biocide’s cost in addition to its effectiveness, toxicity, kill methods, and bacterial resistance. It is a balance issue, as it is with any criterion. A higher price is acceptable if it is a very efficient, all-purpose biocide. A higher cost seems even more reasonable when additional benefits are considered. The cost of raw materials is a clear concern when it comes to silver and copper. To be thorough, however, we must look beyond the basic ingredients and compare cost to efficacy (as well as the following return on investment from increased impact), in order to more clearly identify the winner.
Cost
Both silver and copper are purchased and sold on international marketplaces, which causes considerable fluctuation in their pricing. At the time of writing, silver is selling on average for about $25 per ounce, or $400 per pound. Copper typically costs $3.50 per pound, which is less than 1% of the price of silver. Due to the relative costs of the metals, silver is a far more expensive biocidal than other metals in order to attain the same amount of biocidal activity in the same way (at the proper concentrations).
Silver has logistical challenges as well, which raises the price even more. Surfaces and fittings made of solid silver or silver alloy pose a major risk for theft. Some producers are attempting to mitigate this risk by suspending silver particles in another substance. However, this raises questions about long-term costs because biocidal materials must eventually be replaced at a significant expense because silver ionic activity is not permanent. Even the more cost-effective application of silver as a nanotechnology (little silver particles) has drawbacks because it needs to be applied as a coating that needs to be refreshed on a regular basis. Most notably, none of these applications for silver are economically viable given its effectiveness as a biocide: Silver is an impractical and unsuccessful investment since it needs moisture and high temperatures to function.
the winner Copper It all comes down to cheap, everyday copper. Copper is a lot more effective biocide than aluminum, in addition to being far less expensive. Which gets us to the EPA Registration category, our last category.
EPA Certification
Copper is by far the better biocide when put up against the crucial areas we have discussed over the previous few weeks. One further benefit of copper is included in this list of requirements: EPA-registration. The EPA has registered copper alloys and cuprous-oxide-infused EOSCU Solid Surface for public health claims. Under the “treated article exception,” Silver may only assert that its products are protected from odor and mildew, not the individuals who use them. There is a distinction to be made between avoiding stinking socks and avoiding an infection that was acquired in a hospital. Actually, there is no contest.
the winner A perfect pass rate on tens of thousands of samples exposed to a wide range of pathogens under difficult circumstances is necessary for copper EPA Registration (far more extreme than typical hospital conditions.) Copper alloys and EOSCU Solid Surface are the only solid surfaces to pass these tests, eliminating more than 99.9% of germs in under two hours.
