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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

TestingNew Wellsfor Coliform Bacteria

HELPING ENSURE DRINKING WATER SAFETY

slide2

Why Test Well Water for Coliform Bacteria?

Ensure

Safety of

Drinking

Water

Maintain

Consumer

Confidence

in

Groundwater

Protect Public Health

waterborne pathogen exposure routes

INGESTION

AEROSOL

INHALATION

FOOD

DERMAL CONTACT

Waterborne Pathogen Exposure Routes
what are coliform bacteria
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

coliform bacteria are indicator organisms
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.

slide6

TOTAL COLIFORMS

FECAL COLIFORMS

E. COLI

PATHOGENIC

E. COLI

sources of coliform bacteria

GROUNDWATER

Sources of Coliform Bacteria

INTESTINES

OF

WARM-BLOODED

ANIMALS

SOIL

&

VEGETATION

SURFACE

WATER

&

FLOODWATER

ON-SITE SEWAGE

SYSTEMS &

SEWERLINE

LEAKS

AGRICULTURAL

WASTE RUNOFF

etiologies of waterborne illness outbreaks 1991 2002
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%

slide9

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

slide10

Cryptosporidium

WATERBORNE

PATHOGENS

E. coli

ACUTE GASTROENTERITIS SYMPTOMS:

STOMACH

CRAMPS

DIARRHEA

NAUSEA

VOMITING

FEVER

Symptomatic

Host

slide11

Cryptosporidium

WATERBORNE

PATHOGENS

E. coli

FECAL

TO ORAL

TRANSFER

OF

PATHOGEN

Asymptomatic

Host

Secondary

Host

slide12
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

unsealed abandoned well causes bacteria problems for noncommunity public water supply well
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

potential sources of microbial contamination from well drilling practices
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

introducing contaminants during well construction
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

slide16

DOWNWARD LEAKAGE AROUND UNGROUTED CASING

INFILTRATION OF

SURFACE CONTAMINANTS

CONTAMINANT PLUME

STATIC WATER LEVEL

UNSEALED ANNULAR

SPACE AROUND

CASING

DOWNWARD LEAKAGE

UNCONFINED AQUIFER

slide17

GROUT

PIPE

DIRECT PATHWAY

TO AQUIFER

IF LEFT

UNGROUTED

OR IMPROPERLY

GROUTED

UNSEALED

ANNULUS

BETWEEN

CASING &

BOREHOLE

sanitary preventive practices during well completion
Sanitary & Preventive PracticesDuring Well Completion

CLEAN

DRILLING TOOLS

BETWEEN WELLS

TO PREVENT

CROSS-CONTAMINATION

KEEP WELL COMPONENTS

ELEVATED OFF GROUND…..

USE SANITARY HANDLING

PRACTICES

slide20

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

slide21

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

lhd water sampling activities
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

why should well contractors collect bacteriological water samples
Why Should Well Contractors CollectBacteriological Water Samples?
  • Reduce public health risk
  • Enhance industry professionalism
  • Validate quality of contractors’ work
  • Reduce contractor liability
why should well contractors collect bacteriological water samples24
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
why should well contractors collect bacteriological water samples25
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.
why should well contractors collect bacteriological water samples26
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

work with local building code official

CERTIFICATE

OF

OCCUPANCY

WORK WITH LOCAL BUILDING CODE OFFICIAL

WATER

SUPPLY

APPROVAL

BY LHD

BUILDING

INSPECTOR