Bromate in Drinking Water Document for Public Consultation Prepared by the Federal-Provincial-Territorial Committee on Drinking Water Consultation period ends February 5, 2016 Bromate in Drinking Water Document for Public Consultation Table of Contents Purpose of consultation ................................................................................................................... 1 Part I. Overview and Application................................................................................................ 2 1.0 Proposed guideline .............................................................................................................. 2 2.0 Executive summary ............................................................................................................. 2 2.1 Health effects .......................................................................................................... 2 2.2 Exposure ................................................................................................................. 2 2.3 Analysis and treatment ............................................................................................ 3 3.0 Application of the guideline................................................................................................ 3 3.1 Monitoring .............................................................................................................. 4 Part II. Science and Technical Considerations .......................................................................... 5 4.0 Identity, use and sources in the environment ...................................................................... 5 4.1 Environmental fate .................................................................................................. 5 5.0 Exposure ............................................................................................................................. 5 5.1 Water ....................................................................................................................... 5 5.2 Food ........................................................................................................................ 7 5.3 Air ........................................................................................................................... 8 5.4 Soil .......................................................................................................................... 8 5.5 Consumer products ................................................................................................. 8 6.0 Analytical methods ............................................................................................................. 8 7.0 Treatment technology considerations ............................................................................... 10 7.1 Bromate formation ................................................................................................ 12 7.1.1 Ozonation .................................................................................................. 12 7.1.2 Hypochlorite treatment chemicals ............................................................ 12 7.2 Preventing bromate formation .............................................................................. 13 7.2.1 Ozonation .................................................................................................. 13 7.2.2 Hypochlorite solutions .............................................................................. 14 7.3 Factors influencing bromate formation during ozonation .................................... 15 7.3.1 Bromide concentration .............................................................................. 15 7.3.2 Ozone dose ................................................................................................ 17 7.3.3 Temperature .............................................................................................. 17 7.3.4 pH .............................................................................................................. 18 7.3.5 Alkalinity .................................................................................................. 18 7.3.6 Organic matter .......................................................................................... 19 Guidelines for Canadian Drinking Water Quality: Guideline Technical Document ii 7.3.7 Ammonia................................................................................................... 20 7.3.8 Hydrogen peroxide.................................................................................... 22 7.4 Municipal-scale ozone treatment .......................................................................... 23 7.4.1 Minimizing bromate formation ................................................................. 23 7.4.2 Removal of bromate after formation......................................................... 24 7.4.2.1 Adsorption with activated carbon .............................................. 24 7.4.2.2 Ferrous iron addition .................................................................. 25 7.4.2.3 Ultraviolet irradiation................................................................. 25 7.4.2.4 Membrane technologies ............................................................. 25 7.4.2.5 Anion exchange resins ............................................................... 26 7.4.3 Bromide removal ...................................................................................... 27 7.4.3.1 Reverse osmosis ......................................................................... 27 7.4.3.2 Electrodialysis ............................................................................ 27 7.4.3.3 Ion exchange .............................................................................. 27 7.5 Residential scale.................................................................................................... 28 8.0 Kinetics and metabolism ................................................................................................... 29 8.1 Absorption............................................................................................................. 29 8.2 Distribution ........................................................................................................... 29 8.3 Metabolism ........................................................................................................... 30 8.4 Excretion ............................................................................................................... 30 8.5 PBPK models ........................................................................................................ 30 9.0 Health effects .................................................................................................................... 32 9.1 Effects in humans .................................................................................................. 32 9.1.1 Acute toxicity ............................................................................................ 32 9.1.2 Subchronic and chronic toxicity and carcinogenicity ............................... 32 9.1.3 Reproductive and developmental toxicity ................................................ 32 9.2 Effects on experimental animals ........................................................................... 32 9.2.1 Acute toxicity ............................................................................................ 32 9.2.2 Short-term exposure .................................................................................. 33 9.2.3 Long-term exposure and carcinogenicity .................................................. 34 9.2.4 Genotoxicity .............................................................................................. 36 9.2.4.1 In vitro findings.......................................................................... 36 9.2.4.2 In vivo findings .......................................................................... 37 9.2.5 Reproductive and developmental toxicity ................................................ 39 9.3 Modes of action..................................................................................................... 40 9.3.1 Oxidative stress ......................................................................................... 40 9.3.1.1 Depletion of GSH and surplus of oxidative species .................. 40 9.3.1.2 Damage to DNA, proteins and lipids ......................................... 41 9.3.1.3 Cellular proliferation .................................................................. 41 9.3.1.4 Quantitative analysis of key events for oxidative stress MOA .. 41 9.3.1.5 Synthesis of oxidative stress MOA ............................................ 42 9.3.2 α2µ-globulin nephropathy .......................................................................... 43 9.3.2.1 Accumulation of hyaline droplets in proximal tubules .............. 43 9.3.2.2 Renal protein overload, causing renal cell injury ...................... 43 9.3.2.3 Cellular proliferation .................................................................. 43 Guidelines for Canadian Drinking Water Quality: Guideline Technical Document iii 9.3.2.4 Quantitative analysis of key events for α2µ-globulin nephropathy MOA ............................................................................................. 43 9.3.2.5 Synthesis of α2u-globulin nephropathy MOA ............................ 44 9.3.3 Direct-acting