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Testing New Wells for Coliform Bacteria

Testing New Wells for Coliform Bacteria. HELPING ENSURE DRINKING WATER SAFETY. Why Test Well Water for Coliform Bacteria?. Ensure Safety of Drinking Water. Maintain Consumer Confidence in Groundwater. Protect Public Health. INGESTION. AEROSOL INHALATION. FOOD.

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Testing New Wells for Coliform Bacteria

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  1. TestingNew Wellsfor Coliform Bacteria HELPING ENSURE DRINKING WATER SAFETY

  2. Why Test Well Water for Coliform Bacteria? Ensure Safety of Drinking Water Maintain Consumer Confidence in Groundwater Protect Public Health

  3. INGESTION AEROSOL INHALATION FOOD DERMAL CONTACT Waterborne Pathogen Exposure Routes

  4. What are Coliform Bacteria? • AEROBIC AND FACULTATIVE ANAEROBIC • GRAM-NEGATIVE • NONSPORE-FORMING • ROD-SHAPED FERMENTS LACTOSE WITH GAS PRODUCTION WITHIN 48 HOURS @ 35 DEGREES CELSIUS MEMBRANE FILTER ANALYSIS

  5. Coliform Bacteria are Indicator Organisms Positive coliform test indicates potential presence of pathogenic (disease-causing) microbes Testing for pathogens requires large volumes of water and complex lab procedures Coliforms are found in greater numbers than pathogens E.coli bacteria live longer than fecal coliforms Coliform testing is easier, more economical and safer than pathogen testing.

  6. TOTAL COLIFORMS FECAL COLIFORMS E. COLI PATHOGENIC E. COLI

  7. GROUNDWATER Sources of Coliform Bacteria INTESTINES OF WARM-BLOODED ANIMALS SOIL & VEGETATION SURFACE WATER & FLOODWATER ON-SITE SEWAGE SYSTEMS & SEWERLINE LEAKS AGRICULTURAL WASTE RUNOFF

  8. Etiologies of Waterborne Illness Outbreaks(1991 – 2002) LEGIONELLA 3% OTHER DISEASES 6% ACUTE GASTROINTESTINAL ILLNESS (AGI), UNIDENTIFIED 38% CAMPYLOBACTERIOSIS 3% SHIGELLOSIS 4% AGI – E. COLI 0157:H7 5% AGI – NOROVIRUS 6% CRYPTOSPORIDIOSIS 7% CHEMICAL POISONING 16% GIARDIASIS 12%

  9. Burden of Illness Pyramid (From: Journal of Water and Health, Estimating Disease Risks Associated With Drinking Water Microbial Exposures, Vol. 4, Supplement 2, 2006) Deaths Persons who are hospitalized Persons who visit physician or health care facility Persons who exhibit symptoms Person is exposed to pathogen in water and becomes infected

  10. Cryptosporidium WATERBORNE PATHOGENS E. coli ACUTE GASTROENTERITIS SYMPTOMS: STOMACH CRAMPS DIARRHEA NAUSEA VOMITING FEVER Symptomatic Host

  11. Cryptosporidium WATERBORNE PATHOGENS E. coli FECAL TO ORAL TRANSFER OF PATHOGEN Asymptomatic Host Secondary Host

  12. MICHIGAN GROUNDWATER IS GENERALLY FREE OF: • COLIFORM BACTERIA • DISEASE-CAUSING MICROBES Exceptions: Shallow carbonate bedrock (Karst) Very shallow coarse sand & gravel Faulty well construction Unplugged abandoned wells

  13. Unsealed, Abandoned Well Causes Bacteria Problemsfor Noncommunity Public Water-Supply Well Reported by Minnesota Dept. of Health, Minnesota Well Management News Fall 2006 / Winter 2007, Volume 26, No. 2 PERSISTENT COLIFORMS IN NCPWS (>2 YRS.) (24 YR. OLD WELL - 57 FT. DEEP - 4 IN. CASING) REPEAT WELL DISINFECTIONS UNSUCCESSFUL INVESTIGATION OF FACILITY HISTORY FOLLOWED BY METAL DETECTOR SEARCH BY MDH - ABANDONED WELL WITHIN 10 FT. OF ACTIVE WELL IS SUSPECTED EXCAVATION FINDS OLD WELL UNCAPPED 7 FT. BELOW GRADE, 10 FT FROM ACTIVE WELL - UNSEALED – SAND & DEBRIS FROM 35 FT. TO BOTTOM OF 60 FT. WELL STATIC WATER LEVEL SAME AS ACTIVE WELL – HYDRAULIC CONNECTION BETWEEN WELLS AFTER OLD WELL PROPERLY PLUGGED – CONSISTENT NEGATIVE COLIFORM BACTERIA SAMPLES

  14. Potential Sources of Microbial Contaminationfrom Well Drilling Practices OBTAINING DRILLING WATER FROM SURFACE WATER SOURCE USING BIODEGRADABLE DRILLING FLUID OR LOST CIRCULATION ADDITIVES IRON BACTERIA IN SURFACE WATER

  15. Introducing Contaminants DuringWell Construction FAILURE TO MAINTAIN MINIMUM 10 PPM CHLORINE RESIDUAL IN DRILLING WATER TRANSFERRING CONTAMINANTS FROM GROUND SURFACE INTO WELL BOREHOLE ENCOURAGE DRILLERS TO USE TEST STRIPS

  16. DOWNWARD LEAKAGE AROUND UNGROUTED CASING INFILTRATION OF SURFACE CONTAMINANTS CONTAMINANT PLUME STATIC WATER LEVEL UNSEALED ANNULAR SPACE AROUND CASING DOWNWARD LEAKAGE UNCONFINED AQUIFER

  17. GROUT PIPE DIRECT PATHWAY TO AQUIFER IF LEFT UNGROUTED OR IMPROPERLY GROUTED UNSEALED ANNULUS BETWEEN CASING & BOREHOLE

  18. Would this temporary cap keep contaminantsout of the well?

  19. Sanitary & Preventive PracticesDuring Well Completion CLEAN DRILLING TOOLS BETWEEN WELLS TO PREVENT CROSS-CONTAMINATION KEEP WELL COMPONENTS ELEVATED OFF GROUND….. USE SANITARY HANDLING PRACTICES

  20. PROPER WELL CONSTRUCTION MATERIALS SANITARY WELL COMPLETION PRACTICES TRAINED PROFESSIONAL WATER WELL CONTRACTORS COMPONENTS OF A SAFE & RELIABLE WATER WELL TARGET AQUIFER HAS AMPLE YIELD & SAFE WATER PROPER WATER SYSTEM MAINTENANCE SUFFICIENT SEPARATION FROM CONTAMINATION SOURCES ROUTINE MONITORING OF WATER QUALITY

  21. DEFICIENT WELL HEAD (CRACKED WELL CAP OR OPEN VENT) OLD WELLS WITH CORRODED WELL CASING SHALLOW DEPTH (OR SHORT CASING IN BEDROCK) POOR CONSTRUCTION (UNSEALED ANNULUS OR DUG WELL) FLOODING, BURIED WELL HEAD OR SUBMERGED IN WELL PIT SEWER LINE BREAK, SEWAGE OVERFLOW OR CROSS- CONNECTION TOO CLOSE TO SEPTIC SYSTEM, AGRIC. RUNOFF OR ABANDONED WELL WELLS MOST VUNERABLE TO MICROBIAL CONTAMINATION

  22. LHD Water Sampling Activities COLLECT BACTI SAMPLES OR PROVIDE SAMPLE BOTTLES TO WELL DRILLER OR OWNER USE WELL PERMIT PROGRAM TO NOTIFY WELL OWNER OF NEED TO COLLECT SAMPLE TRACK TEST RESULTS TO ENSURE ALL NEW WELLS ARE TESTED PROMPT FOLLOW-UP ON POSITIVE COLIFORM RESULTS, ESPECIALLY E. COLI POSITIVES WITHHOLD ISSUANCE OF WELL APPROVAL UNTIL SAFE BACTERIOLOGICAL SAMPLES ARE ATTAINED

  23. Why Should Well Contractors CollectBacteriological Water Samples? • Reduce public health risk • Enhance industry professionalism • Validate quality of contractors’ work • Reduce contractor liability

  24. Why Should Well Contractors Collect Bacteriological Water Samples? • Improve customer confidence in groundwater • Reduce customer anxiety over positive test results • Gain better understanding of public health within water well industry

  25. Why Should Well Contractors CollectBacteriological Water Samples? • Current practice leaves customers with sense of purchasing incomplete product • Contractor knows when water system is complete and ready for sampling. • Well owners are unfamiliar with sampling protocol – prone to false positives.

  26. Why Should Well Contractors CollectBacteriological Water Samples? • Contractor ownership of sampling protocol • Fewer disputes over sampling location and technique • Reduction of complaints over validity of sample results • Encourages more sanitary drilling practices

  27. CERTIFICATE OF OCCUPANCY WORK WITH LOCAL BUILDING CODE OFFICIAL WATER SUPPLY APPROVAL BY LHD BUILDING INSPECTOR

  28. Public Health Protection Includes Everyone

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