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NYC DEP Bureau of Water Supply, Water Quality Division of Science and Research Giardia and Cryptosporidium Monitoring in the New York City Watershed A Retrospective. Kerri Alderisio Watershed Science and Technical Conference September 17, 2008 West Point, N.Y.
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NYC DEP Bureau of Water Supply, Water Quality Division of Science and ResearchGiardia and Cryptosporidium Monitoring in the New York City WatershedA Retrospective Kerri Alderisio Watershed Science and Technical Conference September 17, 2008 West Point, N.Y.
“The Conference will bring scientists, engineers and technical experts together with watershed stakeholders and the public, to technically informand present leading-edge research findings oninformation collected to date, with regard to the protection of the nation’s largest unfiltered surface water supply.” - 2008 WSTC brochure
Outline • Are they out there? • Method History • If so, how many? • Data Review • Are there any trends? • Giardia • Are they harmful to people? • Additional Research
Are they out there? • An accurate, reproducible, validated, approved method is paramount to answering this question… • Methods for protozoan recovery have undergone many changes over the past 20 years…
DEP Protozoan Method History(16 years; 3 methods; 3 laboratories)
Other Method Improvements:Pressure and NaHex Experimental Results n=8 56% 45% 39% 18% 12% 1%
Stain Experiment Easy Stain Merifluor EasyStain 2.85 1.06 Avg. Giardia/ 50L 82% 45% Giardia Detection
Stain Differentiation Results • P. Wallis, Hyperion G. muris Same lot # G. intestinalis
Colorseed Experiment (FITC & TR) Faded FITC Damaged cysts Subjective Texas Red
How many are there? • Upstate Keypoints • Kensico Streams • Terminal Keypoints
Giardia at Catskill Sites Combined Giardia at Delaware Sites Combined
Cryptosporidium at Catskill Sites Combined Cryptosporidium at Delaware Sites Combined
Giardia at Eight Kensico Perennial Streams 1993 - 2008
Cryptosporidium at Eight Kensico Perennial Streams 1993 - 2008
Cryptosporidium 1992 - 2008 DEL18 CATLEFF
Down the Pipe! Arrows indicate flow Results are per 50L, US EPA Method 1623 Data from October 2001 – August 2008
Are there any trends? • Temperature • relationship • 1623 stain study • Merifluor • Easystain
Giardia and Temperature DEL18 2002 - 2008 Easy Stain Year
Mean Giardia at CATLEFF by season 2002-2007 Easy Stain year W Avg. = 3.04 W W Sp Sp Sp W W W Su Sp Sp Su Sp Su F F F Su F Su W Su =0.54 F 2002 2003 2004 2005 2006 2007 YEAR
Storm Sites 3 streams ~121 samples (1999-2004) Genotypes 22 Cryptosporidium genotypes found Significance 98%+ not significant human pathogens Most prevalent = deer, rodent, muskrat, skunk Animals 38 different species 541 specimens (2005-2007) Prevalence 111/541 (20%) positive 21 genotypes were found (11/ 21 previously seen in DEP storm water) 6/11 previously unknown 4 novel genotypes! 4 expanded hosts! Storm Samples Wildlife Feces
DEP data up to April 2004 indicate wildlife contribute to Cryptosporidium contamination in stream storm water, but have no major public health significance in cryptosporidiosis
Conclusions • Are they out there? • Yes, and we have a good, improved method • How many are there? • Not a lot, source water is: • ~ 2.0 Giardia / 50L • ~ 0.2Crypto / 50L • Are there any trends? • Yes, Giardia low summer/ higher winter; not enough Crypto detected to be certain • Are they harmful to humans? • Not significant human pathogens (1999-2004)
Thank You! Acknowledgements: S. DiLonardo C. Pace WQ Pathogen Laboratory staff WQ Field staff