Hello, Thanks for adding me to the listserve. I came across an archived conversation from the Silver List about Microdyn and the tests that showed it to be 70ppm rather than the purported 3200ppm (although when I calculated it from literature I read stating its 3.2% silver content, I came up with 32,000ppm). I have been researching colloidal silver, specifically related to clay pot water filters used throughout the developing world, which are painted or dipped with colloidal silver to increase the bacteria killing properties. The silver that seems to be used consistently in the process of making clay filters is Microdyn.
I have created a clay prototype filter that I will be testing in a lab but need to find the right silver to use. All of the research I have found uses 2 mL of the Microdyn colloidal silver at 3.2%, added to 250 mL of water. In light of the testing that found Microdyn at 70ppm and the fact I can't get the product easily on this side of the border, I am wondering what other product I can use instead. I am trying to balance the effective amount of silver to sufficiently kill bacteria while keeping the potential leaching levels below the WHO guideline value (1993) and US EPA drinking water standard (2001) of 0.1 mg/L. I am wondering if you can provide some insight about what product and ppm I should be looking for and how to interpret the formula used by others to find an effective, safe formula I can use without Microdyn. Thank you for your time and assistance. I look forward to your reply. Sarah
