Inactivation of Giardia Cysts by Iodine with Special Reference to Globaline: A Review
Final rept. Apr 1989-Apr 1991
ARMY NATICK RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA
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This review of the literature indicates that iodine is not completely effective in destroying Giardia especially in cold 3 to 15C water. Cysticidal efficacy of iodine at a given concentration and temperature depends on contact time. The iodine tablet, Globaline, used by U.S. Military Forces since 1952, required 60 minutes at 15C, 30 minutes at 25C and 25 minutes at 45C for 100 destruction of Giardia cysts at residual iodine concentration of 10, 8, and 6 mg per liter, respectively. The time required at temperatures below 15C for Globaline tablets to destroy Giardia is not presently known. Based on the information presented in this review, two changes for Globaline are recommended 1 reformulate Globaline tablets with an alkaline buffer and 2 increase the treatment time for one liter of water from 35 minutes to 60 minutes.
- Water Pollution and Control