Novel Polar Disinfection ByProducts and Health Risk Tradeoffs for Drinking Water Disinfection

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Novel Polar Disinfection By-Products and Health
Risk Tradeoffs for Drinking Water Disinfection
Jeffrey Charrois (University of Alberta) Steve
Hrudey (Project Leader, University of
Alberta) Susan Andrews (University of
Waterloo) Ken Froese (University of Alberta)

• November 24, 2005
• Kananaskis Researcher Retreat

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Overall Goal

• Drinking water contamination by microbial
  pathogens is the principal threat to public
  health protection
• Disinfection of drinking water is one of the
  greatest advances in public health
• Long terms exposures to some DBPs may be
  associated with adverse health outcomes

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Research Team

• University of Alberta Team
• Ken Froese (co-investigator)
• Jeff Charrois, Ph.D. (completed Nov 2005)
• Markus Arend (PDF)
• Wojciech Gabryelski (RA)
• University of Waterloo Team
• Susan Andrews (co-investigator)
• Remilekun Adedapo, M.A.Sc. (completed Apr 2005)
• David Hofbauer, M.A.Sc. (completed Aug 2005)
• Wenjun Liu (PDF, now Assoc. Prof., Tsinghua U.)
• Erin Moffat (P/T analytical support)
• Jonathan Musser, Rachelle Ormond, Pamela Kuipers,
  Patrick Tang (UGRAs)
• CRC for Water Quality and Treatment
• Adelaide, Brisbane, and Melbourne, Australia

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Key Challenges/Goals

• Epidemiology data are insufficient to conclude
  that observed associations between bladder cancer
  and chlorinated drinking water are causal (WHO,
  2000)
• Low cancer risk estimates are relevant given
  widespread exposure --- Pop. Attributable Risk
• N. American utilities increasingly incorporating
  alternative disinfection methods as a means to
  comply with current and anticipated DBP regs.
• e.g. chloramination, ozonation, UV disinfection

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Relevant State-of-The-Research

• N-Nitrosamines, have been identified as DBPs, and
  are more toxicologically potent compared to
  conventional DBPs (e.g. THMs and HAAs)
• Effects of UV-mediated disinfection or advanced
  oxidation on NOM and DBPs relatively unknown
• NOM fluorescence an indicator of reactivity to
  form DBPs, some NOM fractionation work

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Approach

• Develop novel analytical methods capable of
  detecting ultra-trace levels of polar DBPs
• ESI-FAIMS-MS
• SPE-GC/MS NH3-PCI
• Bench-scale disinfection
• evaluate formation of NDMA
• UV irradiation experiments
• factorial design pH, UV dose, alkalinity
  considerations
• UV/H2O2 chlorine
• Examine changes in DBP precursor material during
  disinfection
• minimize DBP formation during treatment

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Stage of Research

• This CWN project now completed
• 7 manuscripts either published or accepted
• several more manuscripts in preparation
• numerous (gt10) presentations (AWWA, USEPA,
  Australia, CWN, local AB/ONT, and regional
  utilities) promoting knowledge transfer from CWN
  supported research
• Further CWN N-nitrosamine research and UV-DBP
  research projects in progress

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Key Findings/Observations

• Study high risk Alberta drinking water utilities
  (20032004)
• Non-detect in source waters
• Range of N-Nitrosamine concentrations in plant
  finished and distribution water
• NDMA (lt 1 180 ng/L)
• NPyr (1-4 ng/L)
• NMor (1-2 ng/L)

Not previously reported in drinking water
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Key Findings/Observations
Chlorine Residual (mg/L)
Ave. NDMA Conc (ng/L)
Chlorine Residual (mg/L)
Ave. NDMA Conc (ng/L)
Chlorine dose (mg/L)
Chlorine dose (mg/L)
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Key Findings/Observations
Natural or Synthetic Waters ? UV,
UV/H2O2 ? Cl2, NH2Cl ? -DBP Analysis, -NOM
Recovery and Characterization
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Key Findings/Observations

• UV alone ? little effect on NOM or DBPs
• UV/H2O2 ? NOM fluorescence changes

• Increasing UV/H2O2
• THMs, variable results
• HAAs ? yield Aldehydes ?? yield
• Carboxylic acids ?? yield
• pH effects

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Knowledge Transfer

• J. Charrois invited reviewer for USEPA Method 521
• U of A invited to participate in a blinded,
  multi-centre round robin N-nitrosamine study
  (WateReuse Foundation)
• J. Charrois and S. Andrews invited to participate
  in a USEPA/Health Canada DBP Symposium (June
  2005)
• S. Andrews invited to Beijing and Singapore to
  discuss her DBP work, including CWN research
  (July 2005)
• Drinking water industry more aware of nitrosamine
  issues, considering nitrosamines when planning
  for plant upgrades etc.
• UV disinfection/AOP suppliers and purchasers more
  aware of potential effects on DBPs

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Opportunities

• Further investigation of nitrosamine
  formation/removal
• Investigation of nitrogen containing precursors
• e.g. amino acids, aliphatic and aromatic amines
• investigation of wastewaters
• Nonconventional DBPs and precursor effects with
  UV-mediated processes
• New CWN Project Novel Characterization of New
  Disinfection By-Products and Health Risk
  (Project Leader Dr. X-F Li, U of A)
• New/ongoing CWN Project Integrated Disinfectant
  Strategy Optimization Project (Project
  Leaders Drs. R. Hofmann R. Andrews)

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Collaborative Interests

• Little substantial N-nitrosamine occurrence data
• DBP research is inherently interdisciplinary,
  continued need for collaborative research
• e.g. engineering, chemistry, epidemiology,
  toxicology, policy/regulation, small utilities
  and First Nations
• Significant challenges remain concerning
  knowledge transfer from research community to
  drinking water industry and regulatory community
• CWN facilitating knowledge transfer between
  research disciplines, helping minimize
  duplication and maximize effective use of prior
  experience

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ESI-FAIMS-MS Component
Sample solution
Electrospray Needle
Orifice plate
Curtain Plate
Ring Electrode
Carrier Gas
To Detector
Inner Electrode
Outer Electrode
Skimmer
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City A Temporal Trends poly-DADMAC Dose (mg/L)
and NDMA concs. (ng/L)
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Idealized Breakpoint Chlorination Curve
Idealized Breakpoint Chlorination Curve
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