Document 7: Argyria
Robert C. Holladay, MS
Copyright 2004 Robert C. Holladay
Toxicity from silver ingestion is not a concern, because individuals must ingest horrendous amounts of silver to die from overdose. An individual would exhibit symptoms of argyria well in advance of ingesting enough silver to cause toxicity. Argyria is a condition in which excess amounts of silver are deposited on the outer layers of skin causing it to turn light blue or gray. It is not dangerous, but it is cosmetically undesirable.
A review of the medical literature relating to argyria was conducted by a team of scientists from the United States Environmental Protection Agency for the purpose of including silver in the Integrated Risk Information System. “Health assessment information on a chemical substance is included in IRIS only after a comprehensive review of chronic toxicity data by U.S. EPA health scientists from several Program Offices and the Office of Research and Development. The summaries presented in sections 1 and 2 represent a consensus reached in the review process” (1). The fact that scientists are taken from several different parts of the EPA and are forced to review the relevant literature and come to a consensus eliminates much of the risk of bias or error in the IRIS report. Because of this, the information contained in the IRIS is more reliable than an individual study.
The IRIS gives an oral Reference Dose (RfD) for silver, which is “an estimate of a daily exposure to the human population that is likely to be without an appreciable risk of deleterious effects during a lifetime” (1). The RfD is expressed in units of mg/kg-day, which relates to an individual’s bodyweight. The RfD established for silver is .005mg/kg-day (2). This means an individual that weighs 70 kilograms(154 pounds) could safely ingest .350 milligrams of silver per day for a lifetime. An individual weighing 77 pounds could safely ingest .175 miligrams of silver per day (1).
As previously mentioned, the IRIS was created after an extensive review of
the relevant literature by EPA scientists. They based the RfD on the most thorough and reliable study available
in which 70 cases of argyria were reported by
One teaspoon of 10 ppm colloidal silver contains about 50 micrograms of silver.
The EPA and website can be found by typing “EPA” into any search engine. The specific documents can be found by entering the title in the search box which is available on the EPA website.
(3) Chomchai, S. and S.Y. Kim. 2000. Argyria secondary to chronic ingestion of colloidal silver. Journal of Toxicology. 38: 552.
A 35-year old woman contracted argyria after orally ingesting 66mg of silver from a colloidal silver protein solution over a period of a year.
Comment: There is no mention of anyone testing her colloidal silver solution for silver content. Since this claim is extremely inconsistent with the existing medical literature relating to argyria, the colloidal silver solution she was ingesting probably had a much higher silver content than was reported.
(4) Gaby, Alan R. 2001. Potential hazard of colloidal silver. Townsend Letter for Doctors and Patients. February: 160.
An individual who contracted argyria had been ingesting 3 teaspoons of 200 ppm colloidal silver daily for the past 3 years.
Comment: The silver content of his colloidal silver solution was not tested and therefore this information is not reliable.