Ten production wells drilled in a highly productive sand and gravel aquifer,recharged by an adjacent river, were evaluated for potential Giardia and Cryptosporidiumcontamination. The goal of this study was two-fold: to determine if a correlation existsbetween the occurrence of surface water indicators and Giardia and Cryptosporidium;and, to examine riverbank filtration as a microbial treatment process. Pathogenmonitoring was conducted sporadically over ten years. Intensive monitoring wasconducted for a twenty-month period at ten "flowpath wells" and two production wells.Algae, diatoms and other surface water indicators were found in 57% of 128 groundwater samples. Of 285 groundwater samples collected and analyzed for Giardia orCryptosporidium, no pathogens were detected. No correlation existed between Giardia,Cryptosporidium and surface water indicators. All surrogates demonstrated a minimum4-log reduction. Even though there is hydrologic influence, riverbank filtration is highlyeffective in removing pathogenic protozoa. Includes 26 references, tables, figures.
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Edition: Vol. - No. Published: 06/15/2003 Number of Pages: 18File Size: 1 file , 370 KB