AgdaPkt 2004-10-25 - Laserfiche WebLink

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_ _ _. . �.�-i REPORT . - . To the Honora6le Mayor�and City Council f rom th.e City Manager October 25, 2004 Subject Follow-up Information Concerning Cryptosporidium in Recycled Water Recommendation Receive requested follow-up information — No City Council action required Background In November 2003 the City Council was presented with a copy of the attached abstract entitled "Infectious Cryptosporidium parvum Oocysts in Final Reclaimed EffluenY' from the publication Applied and Environmenta/ Microbiology, dated August 2003. Subsequently, Mayor Ira requested that staff provide follow-up information to tHe City Council. Cryptosporidium and Giardia are protozoan parasites affecting the gastrointestinal tract of humans and animals. They are shed in feces in the form of an oocyst (Cryptosporidium) or cyst (Giardia). These protozoans can remain dormant for long periods in the oocyst/cyst form. They become active upon entering a host. During this protective state (i.e. oocysUcyst), Cryptosporidium and Giardia are particularly difficult to remove from water systems. Ordinary water disinfection techniques cannot kitl oocysts/cysts, and even the best filtration systems occasionally allow a few organisms to pass through. For a more in-depth discussion of Cryptosporidium infection, see the attached Fact Sheet for the general public by the Center for Disease Control (CDC). Since the 1980's, Cryptosporidium and Giardia have become an increasing concem for drinking water industry professionals. The problem became most visible when the Milwaukee, Wisconsin municipal drinking water system suffered a severe Cryptosporidium outbreak in 1993. Over 400,000 persons fell ill and 70 individuals died as a result of this outbreak. After the Milwaukee incident, the EPA began requiring under the Information Coflection Rule (ICR) that municipal drinking water systems serving over 100,000 people test their source waters for Cryptosporidium. However, the methods at that time proved inadequate to detect and enumerate Cryptosporidium. As a result, the EPA initiated in 1996 the proposed development of a new method to overcome the deficiencies of the ICR rule. The attached two-part paper on Cryptosporidium by the San Francisco Public Utilities Commission provides a comprehensive overview of relevant information of Redwood City's drinking water supply. For a discussion on their perspective on the ICR, see page 7 of 13 — "Detection" section. Health problems from Cryptosporidium and Giardia occur only from drinking the water, not from incidental contact. Most mountain streams contain these contaminants making it unsafe to drink. However, people swim in this waterwith no�ill affects. By comparison, the Page 1 of 3 ... _ ..