Alpine E. coli 0157:H7 Outbreak

Barbara BarronDrinking Water ProgramU.S. EPA Region 8

250,000 Gal.

STORAGE

STORAGE

50,000 Gal.

STORAGE

750,000 Gal.

PUMPHOUSE

WELL #2 WELL #1

TO DISTRIBUTION

TO DISTRIBUTION

Intermittent Disinfection

Residentialtaps

Cattle tap

SPRING POND

Municipal WaterSupply - AlpineEstablished 1975

April: Total coliform positiveRepeat samples

negative

May: Total coliform positiveRepeat samples

negative

June: Total coliform positiveRepeat samples

negative

History of BacT Samples in 1998

PRE-OUTBREAK TECHNICAL ASSISTANCE

Site Visit by Contractor

Chlorination Performed

Continuous Chlorination Recommended

250,000 Gal.

STORAGE

STORAGE

50,000 Gal.

STORAGE

750,000 Gal.

PUMP

HOUSE

SPRING

WELL #2 WELL #1

TO DISTRIBUTION Daily TC Sampling

TO DISTRIBUTION

ManualChemicalDisinfection

Cattletap

Shut valve

Residentialtaps

Install firehydrant

Immediate Local Action Under Boil Order

POND

STATE ACTION

Investigation Launched

Assistance Requested from CDC & EPA

Boil Order Continued

Action Under EPA Administrative Order

250,000 Gal.

STORAGE

STORAGE

50,000 Gal.

STORAGE

750,000 Gal.

PUMP HOUSE

Continuous Disinfection

SPRING

WELL #2 WELL #1

TO DISTRIBUTION

TO DISTRIBUTION

Cattletap

Shut valve

Residentialtaps

Install firehydrant

Sever Line

POND

EXAMINING SPRING BOX

Analytical Findings

Spring Pond: Total Coliform + Fecal Coliform + Enterococcus species + Clostridium perfringens +

Storage Tank: Total Coliform + E. coli + Enterococcus species + Clostridium perfringens +

CHANCE OF ACQUIRING INFECTION

CDC Data for Exposure Period 6/25/98 - 7/01/98

Residents who drank Alpine water vs. residents who did not drink Alpine water

Visitors who drank Alpine water vs. visitors who did not drink Alpine water

99.99% certainty that municipal water supply was source of outbreak

Eight times more likely to acquire infection

Fourteen times more likely to acquire infection

Little Jenny Pond/Mill Creek Spring

P

ond

50K

gal tank

Fence Surrounding Spring Collection Area

Fallen Fence

Cattle Corral First Service Connection

Hose Bibb

Alpine Test Results forClassic Contaminants

ContaminantName

Test Date Result

Inorganics 12/06/93 Within limits

Pesticides 11/10/97 Not Detected

Radionuclides 11/10/97 Not Detected

Nitrate/Nitrite 11/10/97 Not Detected

Volatile Organics 12/06/93 Not Detected

Unregulated 11/10/97 Not Detected

Pb/Cu 01/01/98

Where Do We Go From Here?

Direct Implementation Program

A. Sanitary Survey Triage

B. Develop 24hr. Emergency Protocol

C. Strengthen Ties with State Agencies

D. Pilot SWP Program at Alpine

E. Enhance Internal Procedures

F. Continuing Technical Assistance to Alpine