I have tried
Google
www.pdrhealth.com (click drugs and supplements at the time of the page)
www.medlineplus.gov
www.nih.gov
used the search terms
OTC PDR --> to get to the otc drug book, nothing
NIH to see if there are any ongoing studies for "iodine water purification tabs"
medline plus that has all the links to most medicne websites for the public..
tried my nursing sites too.. so far nothing..
will talk to the CRNP at work tomorrow and see if she has heard anything.
perhaps I am using the wrong search phrase?