EPA Review of TCR and Distribution System Issues

1
EPA Review of TCR and Distribution System Issues

• Kenneth H. Rotert
• US EPA Office of Ground Water and Drinking Water
• ASDWA Annual Conference
• October 25, 2001

2
Overview

• Background
• Public Health Concerns
• Activities to Date TCR
• Activities to Date Distribution System Issues
• Upcoming Activities

3
Background

• TCR Review and Revisions Required in SDWA
• not less often than every 6 years, review and
  revise, as appropriate, each NPDWR
• TCR Promulgated in 1989
• M/DBP FACA Agreement (Sept. 2000)
• Evaluate Available Data and Research on Aspects
  of Distribution Systems that may Create Risks to
  Public Health
• Work with Stakeholders to
• Initiate a process for addressing cross
  connection control and backflow prevention
  requirements
• Consider additional distribution system
  requirements related to significant health risks

4
Public Health Concerns

• Outbreaks Related to Distribution Systems
• 66 Distribution System Outbreaks Between
  1981-1998
• 64 of distribution system outbreaks (42) in CWSs
• 21 of distribution system outbreaks (14) in
  NCWSs
• 18 of Outbreaks 1981-1998
• Contaminants in Distribution System Outbreaks
  (CDC Data)
• Chemical Outbreaks with 100 or More Ill or at
  Least One Death
• Copper - 9 outbreaks/125 ill
• Ethylene Glycol - 2 outbreaks/30 ill/1 death
• Microbial Outbreaks with 100 or More Ill or at
  Least One Death
• Campylobacter species - 4 outbreaks/513 ill
• Norwalk virus - 2 outbreaks/225 ill
• Salmonella species - 4 outbreaks/1496 ill
• Giardia species - 10 outbreaks/2034 ill
• AGI - 16 outbreaks/1975 ill
• Shigella species - 4 outbreaks/118 ill
• E. coli - 1 outbreak/243 ill/4 deaths
• SRSV - 1 outbreak/148 ill

5
Activities to Date TCR Review

• Notice of Intent - Six-Year Review
• NOI Being Published Along with Six-Year Review of
  Chemical Contaminants
• Regulatory Review and Development Being Carried
  Out on Separate Track
• Comments Received on TCR
• Unsolicited Comments Reviewed
• Received since 1989 promulgation date
• Solicited Comments January, 2001
• Comments solicited from EPA Regions, States,
  ASDWA, AWWA, AMWA, NRWA and ASM
• Total 66 Letters, 827 Comments

6
Activities to Date TCR Review

• Routine Monitoring Comments
• Increase Minimum to Greater than One Sample Per
  Year
• Base Sampling Frequency on Risk (Cross
  connections, SWAP)
• Waive TC Monitoring if Undisinfected, no
  Distribution System
• Increase Requirements if MCL or Monitoring
  Violation
• Use TC as an Initial Screen with E. coli
  Follow-Up
• Statistically Determine Number of Monthly Samples
  Required
• Review Monitoring Requirements through
  Stakeholder Process
• Follow-up Monitoring Comments
• Drop Fecal Coliforms, Keep E. coli
• Drop Five Routine Samples Following Month
• More Flexible Location for Fourth Repeat Sample
• Clarify Repeats in Systems w/o Distribution
  System
• Better Ways Exist to Determine Plumbing Problem

7
Activities to Date TCR Review

• MCL Comments
• Drop MCL for TC, Keep for E. coli
• Change to Action Level
• Site Sampling Plan Comments
• Greater Flexibility - Emphasize Monitoring
  Critical/Vulnerable Sites
• Allow for Dedicated Sampling Taps
• Concern over Sampling Consumer Taps
• Violation and Reporting Comments
• Reduce Number of Monitoring and Reporting
  Violations
• Streamline and Simplify Reporting
• Definitions Comments
• Re-examine Definitions for MCLs/MCLGs
• Add/Refine Definitions - Violations, Compliance
  and PWS

8
Activities to Date Distribution Systems

• Expert Panel Convened June 2000
• Attendees - OGWDW, ORD, Academia, Utility
  Personnel, AWWSCo., Consultants, State Regulators
• Discussed Health Risks Associated with Various
  Distribution System Issues
• Agreed on the Preparation of White Papers on
  Issues Ranked of Significant Health Risk Concern
• White Paper Purpose
• Characterize Health Risks Associated with
  Distribution System Issues and Potential
  Solutions for Reducing the Risks
• Use as an Informational Source for Regulatory
  Development

9
Activities to Date Distribution System White
Papers

• White Papers Status
• First Drafts Prepared
• Cross Connection Control - (EPA) - Being revised
• Biofilms/Regrowth - (EPA) - Finalizing first
  draft
• First Drafts Under Preparation
• Intrusion - (AWWSCo)
• Aging Infrastructure - (AWWSCo)
• Covered Storage - (AWWA)
• Decay in Water Quality over Time - (AWWA)
• Corrosion, Permeation and Leaching - (AWWA)
• Contamination Following Repair/Replacement -
  (AWWA)
• Nitrification - (AWWA)
• Additional Issues?

10
Cross Connection Control

• Cross Connections Can Lead to Backflow of
  Chemical or Microbial Contaminants
• Where Uncorrected, Cross Connections Can Result
  in Long-Term Exposures.
• Estimated 90 of backflow events unreported
• 26 Cross connection related outbreaks from
  1981-1998 reported to CDC
• EPA Draft Cross Connection White Paper (October,
  1999)
• 448 Backflow Events 1970-1999
• 124 Events Reported Illness - Estimated 11,854
  Cases and 13 Deaths
• Common Contaminants
• Blue/green water - 34 incidents
• Ethylene glycol/antifreeze - 18 incidents
• Chromium species - 18 incidents
• Chlordane - 11incidents
• Giardia - 10 incidents
• Common Elements Being Examined

11
Biofilms/Regrowth

• Several Pathways Through Which Microbes can Enter
  Distribution System
• Microbes can Become Entrained in Biofilm
• Some Organisms can Grow or Recover in Biofilm
• Some Measure of Protection from Disinfectants
  Provided
• Pressure Changes or Erosion Can Release
  Contaminants
• May Interfere with the Utility of Indicator
  Organisms
• Many Control Methods or Approaches Exist
• Some Pathogens of Concern in Biofilms
• Legionella
• Mycobacterium Avium Complex
• Helicobacter (?)

12
Intrusion

• Contaminants Can Enter When Pressure Drops
• Leak Sites Become a Portal for Contaminant
  Intrusion
• Well-Run Systems Average 10-20 Leakage
• Common Causes of Pressure Drops
• Pump Operation
• Flushing Operations
• Opening/Closing Hydrants
• Changes in Demand
• Main Breaks
• Valve Operation
• Power Failures
• Significance of Intrusion
• AWWARF Pathogen Intrusion Study (Kirmeyer et al.,
  2001)
• Most sites had significant pressure drops
• Water samples exterior to pipe - 42.8 fecal
  coliform, 12.5 enteric virus positive

13
Aging Infrastructure

• The Aging of Distribution System Infrastructure
• Average Pipe Age 21-91 Years
• Oldest Sections 35-140 Years
• Pipes Older than 20 Years 42.53 - 69.57
• Current Replacement Rates 0.5 Annually
• Shortened Economic Lives of Materials
• Multiple Generations of Infrastructure to Wear
  Out at Nearly the Same Time
• Life Varies Depending on the Materials
• Effects of Aging Infrastructure
• Leakage and main breaks
• Intrusion
• Backflow
• Enhanced Biofilm Development
• Enhanced Corrosion
• Water Quality Decay

14
Covered Storage

• Contaminants May Be Associated with Sediments
• Coliforms
• Inorganics (e.g., Radium)
• Humans or Animals can Enter and Contaminate
• Some Drowning have been Documented
• Trash Disposal
• Storage Time is a Concern
• Klebsiella (Fecal Coliform) is a Concern in
  Redwood Tanks
• Outbreaks Caused Associated with Covered Storage
  Vessels
• Salmonella typhimurium Outbreak in Gideon, Mo.
• Over 400 cases of illness and seven deaths
• Caused by bird feces contaminating an elevated
  storage tank

15
Decay in Water Quality over Time

• Problems Associated with Excess Residence Times
• Formation of Disinfection and Corrosion
  Byproducts
• Enhances Proliferation of Microbes
• Loss of Disinfectant Residual
• Can Accumulate Contaminants for Later Release
• Inorganics
• Taste, Color and Odor Problems
• Causes of Excess Residence Time
• Improperly Sized Distribution Systems
• Low Flow Areas (e.g., Dead Ends)
• High Demand Storage
• Lack of Valve Exercise

16
Corrosion/Permeation/Leaching

• Corrosion
• Causes Include Water Chemistry, Electric
  Grounding and Microbially-Induced
• Possible Solutions Include Use of Newer Pipe
  Materials and Corrosion Control
• More Understanding Needed on the Effects of
  Changing Chemical Treatment
• Permeation
• Causes Include Plastic Pipes in Close Proximity
  to Gas Tanks (VOCs) and Runoff
• Possible Solutions Include Pipe Placement and the
  Use of Compatible Pipe Materials
• Leaching
• Linings (Including Asphalts with High VOCs),
  Improperly Cured Pipe Materials
• Current Research Exploring the Potential of
  Leaching of Endocrine Disruptors (Include
  Phthalates, Bisphenols, Alkyl Phenols, Alkyl
  Phenol Ethoxylates and Polyethoxylates)

17
Contamination Following Repair/Replacement

• Improper Repair or Replacement Procedures
• Lack of Standardized Procedures
• Need to Return to Service ASAP
• Lack of Proper Flushing and Disinfection
• Effects of Improper Repair and Replacement
• Microbial and/or Chemical Contaminants Introduced
• Problems Associated with Large Releases of
  Chlorine
• Dermal allergies
• Accelerated corrosion
• Customer complaints
• Some Potential Solutions
• Licensed Operators
• Supervisor Oversight
• Replacement Policy and/or Program

18
Nitrification

• May be a Chloramine Issue When Excess Ammonia
  Added
• Added Ammonia May Act as a Nitrogen Source for
  Nitrifying Bacteria
• Also an Issue Related to Naturally-Occurring
  Ammonia and Other Reduced Nitrogen Compounds
• Possible Effects of Excess Nitrogen Source in
  Distribution System
• Proliferation of Some Bacteria Where Nitrogen is
  Growth-Limiting Nutrient
• Increased Health Effects Potential
• Methemoglobinemia
• State of Science on Nitrification Due to
  Chloramine Formation May Warrant Additional
  Information

19
Upcoming Activities

• Complete White Paper Development
• Target Date - February/March, 2002
• Work with Partners to Complete
• Circulate to Interested Co-Regulators and
  Stakeholders
• Begin Evaluating Potential Distribution System
  Solutions/Requirements
• Work with Co-Regulators and Stakeholders to
  Identify High Priority Issues to be Addressed
  Through Regulatory Development

20
Contact Information

• Kenneth H. Rotert
• US EPA
• 1200 Pennsylvania Avenue, NW, Mail Code 4607
• Washington, DC 20460
• E-mail rotert.kenneth_at_epa.gov
• Phone [phone]