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U.S. Department of Health and Human Services

Animal & Veterinary

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Setting a Risk Threshold for Enteric Diseases in Drinking Water

SLIDE 1: EPA WATER REGS. - MICROBIAL CRITERIA & STANDARDS

  • SAFE DRINKING WATER ACT (SDWA) & CLEAN WATER ACT (CWA) REQUIRE PROTECTION AGAINST ILLNESS FROM EXPOSURE.
  • EPA UTILIZES RISK BASED PROCESSES TO PROVIDE CRITERIA OR STANDARDS PROTECTIVE OF HEALTH.
  • IS NEED FOR IMPROVED MICROBIAL RISK ASSESSMENT PROTOCOLS TO MEET MICROBIAL RISK CONCERNS.

 

SLIDE 2: SAFE DRINKING WATER ACT REQS. FOR MICROBIAL RISKS

  • PUBLIC HEALTH GOAL FOR DRINKING WATER IS THAT IT IS SAFE FOR CONSUMPTION.
  • SAFETY = ENTERIC DISEASE OUTBREAK PREVENTION & ENDEMIC DISEASE CONTROL FROM CHRONIC EXPOSURES.
  • DRINKING WATER REGS. PROVIDE ANNUAL RISK LEVEL OF 1 INFECTION PER 10,000 PERSONS. PROTECT GENERAL POPULATION + CHILDREN AND SENSITIVE POPULATIONS.

 

SLIDE 3: SAFE DRINKING WATER ACT REQ.S FOR MICROBIAL RISKS (CONT)

  • HEALTH PROTECTION IS ACHIEVED THROUGH BEST MANAGEMENT (TREATMENT) PRACTICES TARGETED AT SPECIFIC PATHOGENS.
  • UNINFORCEABLE MCLGS (RISKS) ARE DESIGNED TO PROVIDE “O” RISK OF HEALTH EFFECTS.
  • THE RISK FACTOR USED IMPACTS ON THE ACCEPTABLE LEVEL OF MICROBES & WATER TREATMENT REQS.

 

SLIDE 4: SAFE DRINKING WATER ACT REQS. FOR MICROBIAL RISKS (CONT) 

  • SPECIAL GUIDANCE MAY BE PROVIDED TO PROTECT SENSITIVE POPULATIONS IF REGULATED LEVEL OF MICROORGANISMS PROTECTS THE GENERAL POPULATION.
    • E.G., EPA/CDC HAVE BOIL WATER GUIDANCE FOR PERSONS IMPACTED BY AIDS TO REDUCE RISK OF CRYPTOSPORIDIOSIS.

 

SLIDE 5: SAFE DRINKING WATER ACT REQS. FOR MICROBIAL RISKS - ESWTR

  • APPROACH: DETERMINE OCCURRENCE LEVELS OF “WORST CASE” PATHOGENS AND ESTABLISH TREATMENT REQS.
  • REQUIRES UTILITIES TO REMOVE 3 LOGS OF GIARDIA AND 4 LOGS OF ENTERIC VIRUSES (SYNTHETIC VIRUS CONCEPT).
  • TREATMENT, NOT MEASUREABLE MCL OF DW, BECAUSE CAN’T MEASURE ACCURATELY.

 

SLIDE 6: SAFE DRINKING WATER ACT REQS. FOR MICROBIAL RISKS - ESWTR 

  • CRYPTOSPORIDIUM CONTROL BY HIGH TURBIDITY REMOVAL/MONITORING.
  • ALSO WATERSHED PROTECTION & MONITOR DISTRIBUTION SYSTEM (TC RULE).
  • COMPARATIVE RISKS CONSIDERED, E.G., COMPANION DISINFECTION BYPRODUCT RULE MUST NOT INCREASE INFECTIOUS DISEASE RISKS.

 

SLIDE 7: SAFE DRINKING WATER ACT REQS. FOR MICROBIAL RISKS - LT2ESWTR

  • LONG TERM RULE - ADD ON E. COLI & CRYPTOSPORIDIUM ASSESSMENT AT WATER INTAKE - ESTABLISH INDIVIDUAL UTILITY TREATMENT REQS. 0 TO 3 + LOG ADDED TREATMENT IN ADDITION TO ESWTR.)
  • MEETS HACCP?: CONTROL PATHOGEN SOURCES; DETERMINE CONTAMINANT LEVELS AND TREATMENT NEEDS; MONITOR FINISHED WATER FOR COMPLIANCE; REPORT TO STATE.

 

SLIDE 8: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - RECREATIONAL 1

  • EPA ESTABLISHED HEALTH CRITERIA AND INDICATORS OF FECAL CONTAMINATION.
  • CRITERIA TARGET PROTECTION FROM ACUTE ENTERIC INFECTIOUS DISEASE RISKS.
  • HEALTH RISKS WERE DERIVED FROM PROSPECTIVE COHORT EPIDEM. STUDIES ON ADULT BATHERS (HEAD EMERSION STUDIES) WITH PERSONAL FOLLOWUP TO RECORD ILLNESSES.

 

SLIDE 9: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - RECREATIONAL 2

  • CRITERIA ARE RISK BASED FOR AGI DISEASE.
  • ALLOW 8 AGI/1000 SWIMMERS EXPOSED/DAY FOR FRESH WATER; 19 AGI/1000 SWIMMERS EXPOSED/DAY FOR MARINE WATER
    • UTILIZE: ENTEROCOCCI: 33/100ML - MARINE WATER AND 35/100ML - FRESH WATER OR 126 E. COLI/100ML - FRESH WATER ONLY.
  • STATES ESTABLISH PROTECTIVE STDS. BASED ON EPA CRITERIA - CAN BE > PROTECTION.

 

SLIDE 10: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - RECREATIONAL 3

  • CURRENT ACCEPTABLE RISKS ESTABLISHED BASED ON PUBLIC COMMENTS TO 1960’S PHS RECREATIONAL WATER GUIDANCE.
  • CURRENT (1986) CRITERIA WERE PROPOSED TO BE MORE PROTECTIVE BUT WERE RELAXED - SOME STATES COULDN’T REALISTICALLY ACHIEVE LOWER INDICATOR LEVELS IN BATHING WATERS.

 

SLIDE 11: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - RECREATIONAL 4

  • CRITERIA AND INDICATORS NOT PROVEN PROTECTIVE FOR OTHER SWIMMER ILLNESS: SKIN, URT, EYE/EAR, CHRONIC GI.
  • “BEACHES” AMENDMENT TO CWA (FALL ‘00’)
    • EXPANDED CRITERIA & INDICATORS (requires prospective epi studies for new risk based criteria)
    • BETTER MONITORING TO DETECT EXPOSURES
    • COMMUNICATE RISK BETTER TO BEACHGOERS.

 

SLIDE 12: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - BIOSOLIDS 1

  • CFR PART 503 REGULATIONS FOR USE OR DISPOSAL OF SEWAGE SLUDGES (BIOSOLIDS).
  • PART 503 DESCRIBES STANDARD TREATMENT PROCESSES: HIGH TEMP. & PH, OVER TIME, UTILITIES UTILIZE TO REDUCE MICROBES TO SAFE LEVELS FOR FINAL USE OR DISPOSAL.
  • SAFE LEVELS WERE DETERMINED BY RISK ASSESSMENT FOR VARIOUS EXPOSURES.

 

SLIDE 13: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - BIOSOLIDS 2

  • UTILITIES USE STANDARD TREATMENTS TO SIGNIFICANTLY REDUCE PATHOGENS OR CAN PETITION EPA (PEC) IF THEY THINK THEY HAVE EQUIVALENT PROCESSES.
  • MICROBIAL (PATHOGEN) MONITORING IS CONDUCTED ON EACH BIOSOLIDS BATCH AT MULTIPLE LOCATIONS BEFORE FINAL USE OR DISPOSAL - RESULTS MUST MEET NUMERICAL STDS.

 

SLIDE 14: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - BIOSOLIDS 3

  • CLASS A BIOSOLIDS STANDARDS - USE ON GARDENS, CROPS, PLAYGROUNDS, PARKS, ETC., - OK FOR DIRECT HUMAN EXPOSURE:
    • FECAL COLI >1000mpn or cfu/100gm
    • SALMONELLA SP.>3 cfu/4gm
    • ENTERIC VIRUS >1 pfu/4 gm
    • HELMINTH OVA >1 ova/4 gm

 

SLIDE 15: CLEAN WATER ACT REQS. FOR MICROBIAL RISKS - BIOSOLIDS 4

  • CLASS B BIOSOLIDS - RESTRICTED USE TO ELIMINATE DIRECT HUMAN EXPOSURE (CONTROLLED SITE ACCESS)
  • FECAL COLI MUST BE > 2,000,000 CFU BEFORE RELEASE TO ENVIRONMENT.
  • EPA REGIONS APPROVE ALTERNATIVE TREATMENTS PROPOSED BY UTILITIES. STATES MAY HAVE MORE STRICT STDS. FEW STATES WANT PRIMACY.

 

SLIDE 16: CLEAN WATER ACT REQS. FOR MICROBIAL RISK - SHELLFISH WATER 

  • EPA PROVIDES NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) GUIDANCE TO WASTEWATER PERMIT WRITERS AND PROVIDES CLASSIFICATION OF GROWING AREAS.
  • FDA APPROVES SHELLFISH MEATS AND NOAA/NMFS DETERMINES/MAPS OUT SHELLFISH GROWING AREA CLASSIFICATIONS.

 

SLIDE 17: CLEAN WATER ACT REQS. FOR MICROBIAL RISK - SHELLFISH WATER

  • CLASSIFICATION - NOT RIGOROUS RISK BASIS. HISTORICALLY - PREVENT TYPHOID FEVER OUTBREAKS FROM RAW SHELLFISH.
  • EPA CLASSIFICATION OF GROWING AREAS:
    • APPROVED AREAS: TC GEOM. MEAN OF 70/100ML MPN (<10% SAMPLES CAN EXCEED 230/100 ML MPN) OR
      FC GEOM. MEAN OF 14/100ML MPN (<10% SAMPLES CAN EXCEED 43/100ML MPN).

 

SLIDE 18: CLEAN WATER ACT REQS. FOR MICROBIAL RISK - SHELLFISH WATER

  • CONDITIONALLY APPROVED - INTERMITTANT, BUT PREDICTABLE CONTAMINATION - USE TREATMENT PLANT MANAGEMENT.
  • RESTRICTED AREAS - LIMITED POLLUTION BUT MANAGED BY RELAYING OR DEPURATION.
  • CONDITIONALLY RESTRICTED - POLLUTION INTERMITTANT BUT CAN RELAY/DEPURATE.
  • PROHIBITED - SHELLFISH UNUSEABLE FOR CONSUMPTION, BUT CAN USE FOR STOCK.