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The Iowa Community Private Well Study: Random Sampling

Iowa Community Private Well Study. Private Well Water Quality. No regulatory mechanism for samplingSafe Drinking Water Act applies only to public water systemsPopulation at risk ?generally shallow alluvial wells; vulnerable to proximate point / nonpoint contaminant sourcesIowa population using

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The Iowa Community Private Well Study: Random Sampling

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    1. The Iowa Community Private Well Study: Random Sampling Peter Weyer Center for Health Effects of Environmental Contamination The University of Iowa

    2. Iowa Community Private Well Study Private Well Water Quality No regulatory mechanism for sampling Safe Drinking Water Act applies only to public water systems Population at risk ? generally shallow alluvial wells; vulnerable to proximate point / nonpoint contaminant sources Iowa population using groundwater as drinking source 1.5 M served by community water supplies 240,000 use private wells

    3. U.S. EPA

    4. Statewide Rural Well Water Survey (SWRL) 1988-89 sampling of 856 private rural wells nitrate, bacteria, pesticides Nitrate (NO3-N) 18.3% of rural private wells statewide >10mg/L 35% of wells < 50 feet deep (statewide) >10 mg/L ~ 130,000 rural Iowa residents use well water with high nitrate Atrazine 8% of wells statewide had atrazine detection mean = 1.14 ppb; max = 7.71 ppb varied by region and well depth

    5. Iowa SDWA

    6. Iowa Community Private Well Study Iowa Community Private Well Study Random Sampling One time sampling of 103 randomly selected private wells in 50 Iowa communities without public water systems Conducted from June 2002 - January 2003 Funded by Iowa Department of Natural Resources, U.S. Geological Survey, UI Hygienic Laboratory, CHEEC Conducted by CHEEC, UHL, USGS, UI Environmental Health Sciences Research Center

    7. Iowa Community Private Well Study Well Sampling Design Incorporated communities without public water systems initially 124 communities eligible Weighted by number of households within a community assumption: each household has private well Random number generation selected 120 wells 57 communities total; rural water in 7 communities

    8. Iowa Community Private Well Study Well Sampling Locations

    9. Iowa Community Private Well Study Well Sampling Design Orthophoto maps used to identify community boundaries polygon drawn around boundary ARCView GIS randomly selected points within polygon based on number of samples to be taken

    11. Iowa Community Private Well Study Community Contact and Risk Communication Communities notified by letters and press releases sent to local newspapers County sanitarians visit study communities identify sampling locations collect water samples administer well construction / contaminant site survey Follow-up letters to well owners detections, health effects information Regional meetings to discuss results

    12. Iowa Community Private Well Study Water Sample Analyses Water samples analyzed at UHL total and fecal coliform bacteria nitrate + nitrite as NO3 ; ammonia nitrogen as N nitrogen-containing herbicides and organophosphate/carbamate insecticides regulated, unregulated & discretionary VOCs arsenic 10% duplicate sample and analysis by USGS

    13. Iowa Community Private Well Study Herbicide Detections Random Sampling

    14. Iowa Community Private Well Study Inorganics and Bacteria Detections Random Sampling

    15. Iowa Community Private Well Study Disinfection By-products / VOC Detections Random Sampling

    16. Iowa Community Private Well Study Contaminant Detections and Well Characteristics Random Sampling

    17. Iowa Community Private Well Study SWRL and ICPWS Random Sampling Statewide Comparison

    18. Iowa Community Private Well Study SWRL and ICPWS Random Sampling Regional Comparison

    19. Iowa Community Private Well Study Conclusions Nitrate continues to be a problem 23% of wells >10 ppm Atrazine/metabolite detections have increased 19% atrazine, 28% DEA Arsenic prevalent 26% detections Well depth / construction important factors

    20. Iowa Community Private Well Study Recommendations / Future Research Recommendations team approach: sanitarians, geologists, epidemiologists model for prospective studies Future research sampling wells in unincorporated areas SWRL sampling frame: 20% annually

    21. Research Collaborators �Fall Plowing� by Grant Wood Courtesy of the Deere Art Collection, Moline, Illinois Iowa County Environmental Health Specialists Jessica Ferrie: UI Dept of Occupational & Environmental Health Michael Wichman, Lorelei Kurimski , Terry Cain: UI Hygienic Laboratory Brent Parker, Mary Skopec, Robert Libra: Iowa Dept. Natural Resources David Osterberg: UI Environmental Health Sciences Research Center Douglas Schnoebelen, Robert Buchmiller: U.S. Geological Survey David Riley, Jiji Kantamneni, Zheng Fang Feng: CHEEC

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