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Document ID ca-1drwa-2018-09-07 Title 1,4-dioxane in Drinking Water - Guideline Technical Document for Public Consultation URL https://www.canada.ca/en/health-canada/programs/consultation-1-4-dioxane-drinking-water/document.html Jurisdiction /ca Subdomain(s) Drinking water, Water treatment, Monitoring and analysis Language en Status completed Analyzed at 2026-03-17 12:32:53.832483+00:00 Relevance Proposed drinking water guideline including treatment and analytical methods.

Q Qualitative Requirements (20)

Req ID Category Intent Legal Status Name Subdomain(s) Context Conditions Confidence
#Q001administrativeunknownrecommendedGuidance Source for Implementationdrinking waterNote: Specific guidance related to the implementation of drinking water guidelines should be obtained from the appropriate drinking water authority in the affected jurisdiction.high
#Q002monitoringoperationalrecommendedSource Water Characterizationdrinking waterUtilities should characterize their source water to determine the concentration of 1,4-dioxane.high
#Q003monitoringoperationalrecommendedSemi-Annual Monitoring for Impacted Sourcesdrinking waterSemi-annual monitoring should be conducted for sources that are known to be impacted by industrial wastes, landfill leachate, wastewater effluent and/or sources that contain chlorinated solvents.For sources known to be impacted by industrial wastes, landfill leachate, wastewater effluent and/or sources that contain chlorinated solventshigh
#Q004monitoringoperationalguidanceReduced Monitoring Frequencydrinking waterUtilities with baseline data indicating that 1,4-dioxane is not present in source water may conduct less frequent monitoring.When baseline data indicates 1,4-dioxane is not present in source waterhigh
#Q005designtreatmentrecommendedTreatment System Design and Maintenancedrinking waterTherefore, these treatment systems should be carefully designed and maintained to ensure that they are effective for treating 1,4-dioxane.When specific treatment processes are used to remove 1,4-dioxanehigh
#Q006monitoringoperationalrecommendedCompliance Monitoring for Treated Waterdrinking waterWhen treatment is in place for 1,4-dioxane, compliance monitoring of the treated water should be conducted semi-annually and in conjunction with monitoring of the source water to confirm the efficacy of treatment.When treatment is in place for 1,4-dioxanehigh
#Q007monitoringoperationalrecommendedSample Collection Locationdrinking waterDrinking water samples should be collected after treatment and prior to distribution (typically at the entry point to the distribution system).high
#Q008administrativeunknownrecommendedVerification of Analytical Methodsdrinking waterThe responsible authorities should discuss the method being used by the laboratory and ensure that the appropriate method detection limit (MDL) or MRL is being achieved in order to adequately assess whether 1,4-dioxane is below the MAC.high
#Q009designtreatmentrecommendedBench and Pilot-Scale Testingdrinking waterBench- and pilot-scale testing prior to design and installation of a treatment system is recommended.high
#Q010treatmenttreatmentmandatoryH2O2 Dose Optimization and Quenchingdrinking waterConsideration needs to be given to optimizing the H2O2 dose and quenching the excess H2O2 following the AOP process, which is typically achieved using chemical additions (free chlorine, sulphur-based reducing agents) or GAC (U.S. EPA, 2011).When using UV combined with H2O2 advanced oxidation systemshigh
#Q011operationaloperationalrecommendedUnderstanding Source Water Chemistry for H2O2/O3 Systemsdrinking waterUtilities considering H2O2/O3 for treatment of 1,4-dioxane should have a good understanding of the sources and concentration of bromide in their source waters and the seasonal variability of water quality parameters that may affect the formation of bromate or other disinfectant by-products (Health Canada, 2016).When considering H2O2/O3 for treatment of 1,4-dioxanehigh
#Q012treatmenttreatmentmandatoryExcess H2O2 Quenchingdrinking waterQuenching of excess H2O2 needs to be conducted at the end of the treatment process.When using H2O2/O3 systemshigh
#Q013treatmenttreatmentrecommendedResidential Treatment Device Recommendationdrinking waterGenerally, it is not recommended that drinking water treatment devices be used to provide additional treatment to municipally treated water.high
#Q014monitoringoperationalrecommendedPre-installation Water Testingdrinking waterBefore a treatment device is installed, the water should be tested to determine its general water chemistry and verify the presence and concentration of 1,4-dioxane.Before installing a residential treatment devicehigh
#Q015monitoringoperationalrecommendedPeriodic Treatment Device Testingdrinking waterPeriodic testing by an accredited laboratory should be conducted on both the water entering the treatment device and the finished water to verify that the treatment device is effective.For installed residential treatment deviceshigh
#Q016operationaloperationalmandatoryDevice Maintenance and Replacementdrinking waterDevices can lose removal capacity through use and time and need to be maintained and/or replaced.For residential treatment deviceshigh
#Q017administrativeunknownrecommendedTreatment Device Certificationdrinking waterHealth Canada does not recommend specific brands of drinking water treatment devices, but it strongly recommends that consumers use devices that have been certified by an accredited certification body as meeting the appropriate NSF International (NSF)/American National Standards Institute (ANSI) drinking water treatment unit standards.high
#Q018administrativeunknownmandatoryCertification Organization Accreditationdrinking waterCertification organizations provide assurance that a product conforms to applicable standards and must be accredited by the Standards Council of Canada (SCC).high
#Q019administrativeunknownrecommendedSystem Materials Certificationdrinking waterconsumers should ensure that the materials used to construct the system have been certified to NSF/ANSI Standard 61: Drinking Water System Components: Health Effects (NSF/ANSI, 2016).For point-of-entry activated carbon systemshigh
#Q020treatmenttreatmentguidanceInfluent Water Pretreatmentdrinking waterA consumer may need to pretreat the influent water to reduce fouling and extend the service life of the membrane.When using RO systems certified to NSF/ANSI Standard 58medium

P Quantitative Requirements (42)

Req ID Category Intent Legal Status Name Subdomain(s) Limit Type Limit Value Context Conditions Confidence
#P001chemicalhealthguideline1,4-dioxanedrinking waterMAC0.050 mg/LA maximum acceptable concentration (MAC) of 0.050 mg/L (50 µg/L) is proposed for 1,4-dioxane in drinking water.high
#P002chemicalhealthguideline1,4-dioxanedrinking waterMAC50 µg/LA maximum acceptable concentration (MAC) of 0.050 mg/L (50 µg/L) is proposed for 1,4-dioxane in drinking water.high
#P003chemicalhealthguideline1,4-dioxanedrinking waterrequirement0.05 mg/LThe World Health Organization (WHO, 2005) has established a guideline value of 0.05 mg/Ltaking into consideration both cancer and non-cancer effectshigh
#P004chemicalhealthguidance1,4-dioxanedrinking waterrequirement1 µg/LThe California EPA has also not set a maximum contaminant level but has a drinking water notification (CalEPA, 2014) level of 1 µg/Lhigh
#P005chemicalreportingmandatory1,4-dioxanedrinking waterrequirement0.07 µg/LThis rule stipulates that using Method 522 an MRL of 0.07 µg/L must be achieved by the laboratories conducting the analysesUnder U.S. EPA UCMR 3high
#P006operationalreportingguidance1,4-dioxane (EPA Method 522 MDL)drinking waterrequirement0.020 µg/LThe MDL for this method is 0.020 μg/L.Using EPA Method 522high
#P007operationalreportingguidance1,4-dioxane (EPA Method 541 LCMRL)drinking waterrequirement0.074 µg/LThe single laboratory LCMRL for this method is 0.074 μg/LUsing EPA Method 541high
#P008operationalreportingguidance1,4-dioxane (EPA Method 8015C MDL)drinking waterrequirement15 µg/LThe MDLs are 15 μg/L and 12 µg/L for methods 8015C and 8260B, respectivelyWhen azeotropic distillation is used for sample preparationhigh
#P009operationalreportingguidance1,4-dioxane (EPA Method 8260B MDL)drinking waterrequirement12 µg/LThe MDLs are 15 μg/L and 12 µg/L for methods 8015C and 8260B, respectivelyWhen azeotropic distillation is used for sample preparationhigh
#P010operationaloperationalrecommendedSource Water Monitoring Frequencydrinking waterrequirement2 times per yearSemi-annual monitoring should be conducted for sources that are known to be impacted by industrial wastes, landfill leachate, wastewater effluent and/or sources that contain chlorinated solvents.Sources impacted by industrial wastes, landfill leachate, wastewater, or chlorinated solventshigh
#P011operationalreportingmandatoryCompliance Monitoring Frequencydrinking waterrequirement2 times per yearWhen treatment is in place for 1,4-dioxane, compliance monitoring of the treated water should be conducted semi-annually and in conjunction with monitoring of the source waterWhen specific treatment is in place for 1,4-dioxanehigh
#P012physicalaestheticguidanceOdour Thresholddrinking waterAO230 ppm1,4-dioxane has a reported odour threshold of 24 ppm in air and 230 ppm in waterhigh
#P013physicalaestheticguidanceOdour Threshold (Air)otherAO24 ppm1,4-dioxane has a reported odour threshold of 24 ppm in air and 230 ppm in waterhigh
#P014operationalreportingguidance1,4-dioxane (EPA Method 522 LCMRL - Lab 1)drinking waterrequirement0.036 µg/LTwo single laboratory LCMRLs of 0.036 μg/L and 0.047 μg/L were determined using this method and reagent waterUsing EPA Method 522high
#P015operationalreportingguidance1,4-dioxane (EPA Method 522 LCMRL - Lab 2)drinking waterrequirement0.047 µg/LTwo single laboratory LCMRLs of 0.036 μg/L and 0.047 μg/L were determined using this method and reagent waterUsing EPA Method 522high
#P016unknownhealthguidanceTolerable Daily Intake (TDI)drinking watertreatment_goal0.0054 mg/kg bw per dayThe TDI for 1,4-dioxane is 0.0054 mg/kg bw per day. This is calculated by dividing the BMDL5 of 5.4 mg/kg bw per day by the uncertainty factor (UF) 1000.Based on hepatocellular necrosis using combined incidence data from male and female ratshigh
#P017unknownhealthguidanceBenchmark Dose Lower Limit (BMDL5)drinking waterrequirement5.4 mg/kg bw per dayThe lower 95% confidence limit on the BMD for a 5% response (BMDL5) of 5.4 mg/kg bw per day for male and female rats combined... has been selected as the point-of-departurePoint-of-departure for calculation of the HBVhigh
#P018operationalhealthguidanceDefault Allocation Factor (AF)drinking waterrequirement0.2 dimensionlessa default allocation factor for 1,4-dioxane in drinking water of 0.2 is justified.high
#P019operationalhealthguidanceAverage Adult Body Weightdrinking waterrequirement70 kg70 kg is the average body weight of an adult;high
#P020operationalhealthguidanceTotal Daily Exposure Contribution from Drinking Waterdrinking waterrequirement1.5 L/day1.5 L/day is the total daily exposure contribution from drinking water for an adult.high
#P021unknownhealthguidanceTotal Uncertainty Factor (UF)drinking waterrequirement1000 dimensionless1,000 is the uncertainty factor: x10 for interspecies variability, x10 for intraspecies variability and x10 for database deficiencieshigh
#P022operationalhealthguidanceMulti-route Exposure Tier 1 Goal (L-eq)drinking waterrequirement0.15 L-eqFor dermal exposure, the tier 1 goal of 0.15 L-eq is associated with a skin permeability coefficient (Kp) for VOCs of 0.024 cm/hhigh
#P023operationalhealthguidanceSkin Permeability Coefficient (Kp) Thresholddrinking waterrequirement0.024 cm/hthe tier 1 goal of 0.15 L-eq is associated with a skin permeability coefficient (Kp) for VOCs of 0.024 cm/hhigh
#P024operationalhealthguidanceAir to Water Concentration Ratio (Fair:water) Thresholddrinking waterrequirement0.00063 ratiothe tier 1 goal of 0.15 L-eq is associated with an air to water concentration ratio (Fair:water) value of 0.00063high
#P025operationalhealthguidanceExposure Assessment Ventilation Rate (Adult)drinking waterrequirement675 L/ha ventilation rate of 675 L/h for adults, and an absorption fraction of 0.7.high
#P026operationalhealthguidanceExposure Assessment Absorption Fractiondrinking waterrequirement0.7 fractiona ventilation rate of 675 L/h for adults, and an absorption fraction of 0.7.high
#P027chemicalhealthguidanceUS EPA Reference Dose (RfD)drinking watertreatment_goal0.03 mg/kg bw per dayThe U.S. EPA has not established a maximum contaminant level for 1,4-dioxane. However, the agency used the results of the Kociba et al. (1974) study to derive a reference dose of 0.03 mg/kg bw per day.Based on a NOAEL of 9.6 mg/kg bw per day for liver and kidney degenerationhigh
#P028chemicalhealthguidanceUS EPA Oral Cancer Slope Factordrinking waterrequirement0.1 mg/kg bw per dayAn oral cancer slope factor of 0.1 mg/kg bw per day was calculated using the linear multistage model for carcinogenesis, based on BMD modelling of hepatocellular adenoma and carcinoma in female BDF1 mice.Based on benchmark response of 50%high
#P029chemicalhealthguidanceATSDR Minimal Risk Level (MRL)drinking watertreatment_goal0.1 mg/kg bw per dayATSDR (2012) calculated a minimal risk level of 0.1 mg/kg bw per day, based on a NOAEL of 9.6 mg/kg bw per day for liver effects in male rats from the Kociba et al. (1974) study.Based on liver effects in male ratshigh
#P030chemicalhealthmandatoryFood Additive Maximum Permitted 1,4-Dioxane Residuedrinking waterrequirement10 mg/kgThe assessment assumed that 1,4-dioxane was present as an impurity in four permitted food additives (polysorbate 60, 65, and 80, and polyethylene glycol) at the maximum level permitted by the food-grade specifications (10 mg 1,4-dioxane per kg food additive).Maximum level permitted by food-grade specificationshigh
#P031designtreatmentguidanceH2O2/O3 Applied Ratio Rangedrinking waterrequirement0.2 - 3.0 ratioThe typically applied ratio of H2O2/O3 is between 0.2 and 3.0; it is a function of disinfection requirements, bromide concentration, contaminant concentration, and other water quality parameters.Function of bromide, contaminant concentration, and disinfection requirementshigh
#P032unknownhealthguidelineNOAEL (Hepatocellular degeneration and necrosis - Kociba study)drinking waterrequirement9.6 mg/kg bw per dayHepatocellular degeneration, necrosis, and hyperplastic nodules were observed in male rats at doses of 94 mg/kg bw per day and above (LOAEL; NOAEL 9.6 mg/kg bw per day) (Kociba et al., 1974)Based on a 2-year drinking water study in Sherman ratshigh
#P033unknownhealthguidelineLOAEL (Hepatocellular degeneration and necrosis - Kociba study)drinking waterrequirement94 mg/kg bw per dayHepatocellular degeneration, necrosis, and hyperplastic nodules were observed in male rats at doses of 94 mg/kg bw per day and above (LOAEL; NOAEL 9.6 mg/kg bw per day) (Kociba et al., 1974)Based on a 2-year drinking water study in Sherman ratshigh
#P034unknownhealthguidelineNOAEL (Spongiosis and hyperplasia - JBRC study)drinking waterrequirement11 mg/kg bw per dayspongiosis and hyperplasia of the liver were noted in male rats at 55 mg/kg bw per day and above (LOAEL; NOAEL 11 mg/kg bw per day) (Yamazaki et al., 1994; JBRC, 1998; Kano et al., 2009).Based on a 2-year drinking water study in F344/DuCrj ratshigh
#P035unknownhealthguidelineLOAEL (Spongiosis and hyperplasia - JBRC study)drinking waterrequirement55 mg/kg bw per dayspongiosis and hyperplasia of the liver were noted in male rats at 55 mg/kg bw per day and above (LOAEL; NOAEL 11 mg/kg bw per day) (Yamazaki et al., 1994; JBRC, 1998; Kano et al., 2009).Based on a 2-year drinking water study in F344/DuCrj ratshigh
#P036operationalreportingmandatoryPublic Consultation Period Durationdrinking waterrequirement60 daysThe document is being made available for a 60-day public consultation period.Period ending November 9, 2018high
#P037chemicalhealthguidelineWHO Cancer Risk Leveldrinking waterrequirement10^-5 dimensionlessThe linear extrapolation employed a linearized multistage model for estimating cancer risk based on hepatic tumours in rats (Yamazaki et al., 1994) at a 10-5 cancer risk levelUsed for linearized multistage model extrapolationhigh
#P038chemicalhealthguidelineWHO Cancer Risk Model Concentrationdrinking waterrequirement0.054 mg/Lwhich resulted in a value of 0.054 mg/L.Calculated based on 10^-5 cancer risk levelhigh
#P039unknownhealthguidanceUS EPA Uncertainty Factor (UF)drinking waterrequirement300 dimensionlessapplying an uncertainty factor of 300 (10 each for inter- and intra-species variation and 3 for database deficiencies)Used to derive US EPA reference dose of 0.03 mg/kg bw per dayhigh
#P040operationalhealthguidanceMulti-route Exposure Durationdrinking waterrequirement0.5 hwhich is based on an exposure time of 0.5 hAssumption for tier 1 multi-route exposure assessmenthigh
#P041operationalreportingguidanceLCMRL Analytical Recovery Criteriadrinking waterrequirement50 - 150 %lowest concentration minimum reporting limit (LCMRL) as the lowest spiking concentration at which recovery of between 50% and 150% is expectedDefinition of LCMRL accuracyhigh
#P042operationalreportingguidanceLCMRL Analytical Confidence Criteriadrinking waterrequirement99 %is expected 99% of the time by a single analyst.Definition of LCMRL precision/probabilityhigh

D Definitions (86)

Req ID Category Name Context Confidence
#D001lowest concentration minimum reporting limit (LCMRL)the lowest spiking concentration at which recovery of between 50% and 150% is expected 99% of the time by a single analysthigh
#D002Electrical Energy per Order (EEO)the number of kilowatt-hours (kWh) of electrical energy required to reduce the concentration of a pollutant by one order of magnitude (90%) in one cubic meter of contaminated water.high
#D003AFallocation factorhigh
#D004ALTalanine aminotransferasehigh
#D005ANSIAmerican National Standards Institutehigh
#D006AOPadvanced oxidation processhigh
#D007AUCarea under the curvehigh
#D008BMDbenchmark dosehigh
#D009BMDLlower confidence limit on the benchmark dosehigh
#D010BMDL5lower 95% confidence limit on the benchmark dose for a 5% responsehigh
#D011bwbody weighthigh
#D012CYPcytochrome P450 enzymehigh
#D013DENdiethylnitrosaminehigh
#D014DLdetection limithigh
#D015EPAEnvironmental Protection Agency (United States)high
#D016GACgranular activated carbonhigh
#D017GCgas chromatographyhigh
#D018GGTgamma-gluramyltransferasehigh
#D019HBVhealth-based valuehigh
#D020HEAAβ-hydroxyethoxy acetic acidhigh
#D021JBRCJapan Bioassay Research Centrehigh
#D022LCMRLlowest concentration minimum reporting limithigh
#D023LOAELlowest-observable-adverse-effect levelhigh
#D024MACmaximum acceptable concentrationhigh
#D025MDLmethod detection limithigh
#D026MRLminimum reporting levelhigh
#D027MSmass spectrometryhigh
#D028NCINational Cancer Institutehigh
#D029NOAELno-observed-adverse-effect levelhigh
#D030NTPNational Toxicology Programhigh
#D031PBPKphysiologically-based pharmacokinetichigh
#D032POEpoint-of-entryhigh
#D033POUpoint-of-usehigh
#D034ROreverse osmosishigh
#D035TCA1,1,1-trichloroethanehigh
#D036TCEtrichloroethylenehigh
#D037TDItolerable daily intakehigh
#D038TWAtime-weighted averagehigh
#D039UCMR 3Unregulated Contaminant Monitoring Rulehigh
#D040UVultraviolethigh
#D041VOCvolatile organic compoundhigh
#D042minimum reporting level (MRL)the lowest concentration of an analyte that can be determined with an acceptable level of accuracy and precisionhigh
#D043Fenton processH2O2 and ferrous iron processhigh
#D044significantcontributes at least 10% of the drinking water consumption level (i.e., 10% of 1.5 L)high
#D045hydropic changesreversible cellular swelling/vacuolar changes due to the inability to maintain ionic and fluid equilibriumhigh
#D046angiectasisgross dilatation of blood vesselshigh
#D047labelling indexproportion of hepatocytes actively synthesizing DNAhigh
#D048L-eqlitre equivalentshigh
#D049Kpskin permeability coefficienthigh
#D050Fair:waterair to water concentration ratiohigh
#D051Kowlog octanol-water partition coefficienthigh
#D052MWCOmolecular weight cut-offhigh
#D053peroxone processprocess where H2O2 is added during the second stage of operation by injecting it into the second chamber of an O3 contactorhigh
#D054LPHOlow pressure high output (lamps)high
#D055H2O2hydrogen peroxidehigh
#D056O3ozonehigh
#D057CDWFederal-Provincial-Territorial Committee on Drinking Waterhigh
#D0581,1-DCE1,1-dichloroethenehigh
#D059PETpolyethylene terephthalatehigh
#D060NPRINational Pollutant Release Inventoryhigh
#D061THFtetrahydrofuranhigh
#D062TPA12-O-tetradecanoylphorbol-13-acetatehigh
#D063PCE/NCEpolychromatic erythrocyte/ normochromatic erythrocytehigh
#D064ISSInstituto Superiore di Sanitahigh
#D065BMRbenchmark responsehigh
#D066AICAkaike Information Criterionhigh
#D067UFuncertainty factorhigh
#D068International Agency for Research on Cancer (IARC)classified 1,4-dioxane as “possibly carcinogenic to humans” (group 2B) based on sufficient evidence in experimental animals and inadequate evidence in humans.high
#D069selected ion monitoring (SIM)mass spectrometer operated in selected ion monitoring (SIM) mode.high
#D070solid-phase extraction (SPE)the most common sample preparation methods used to achieve reporting limits below 1 µg/L.high
#D071flame ionization detection (FID)gas chromatography (GC) with flame ionization detection (FID)high
#D072specific pathogen free (SPF)male F344/DuCrj specific pathogen free (SPF) ratshigh
#D073diethylene glycol (DEG)HEAA was the major metabolite in urine collected from rats injected with diethylene glycol (DEG)high
#D074computer automated structural evaluator (CASE)structure activity method was also used to predict whether 1,4-dioxane would be a carcinogen in rats and mice and would be a non-genotoxic carcinogenhigh
#D075nanofiltration (NF)RO and to a much lesser extent nanofiltration (NF) may be effective for 1,4-dioxane removal.high
#D076Standards Council of Canada (SCC)accredited by the SCC to certify drinking water devices and materials as meeting NSF/ANSI standardshigh
#D077Bureau de normalisation du Québec (BNQ)accredited by the SCC to certify drinking water devices and materials as meeting NSF/ANSI standardshigh
#D078International Association of Plumbing & Mechanical Officials (IAPMO)accredited by the SCC to certify drinking water devices and materials as meeting NSF/ANSI standardshigh
#D079Water Security Agency (WSA)The Water Security Agency (WSA) has reviewed the proposed guideline document for 1,4-dioxane in drinking water and supports the proposed MAC of 0.05 mg/L (50 µg/L).high
#D080Integrated Risk Information System (IRIS)Toxicological review of 1,4-dioxane (with inhalation update) (CAS no. 123-91-1) in support of summary information on the integrated risk information system (IRIS).high
#D081D-1,4-dioxanedeuterated 1,4-dioxanehigh
#D0821,4-dioxanea cyclic ether with a molecular mass of 88.1 g/molhigh
#D083Advanced oxidation processes (AOPs)include the use of appropriate combinations of chemical oxidants (e.g., O3, H2O2 and/or UV) to generate highly reactive hydroxyl radicals, which rapidly and non-selectively oxidize organic contaminants.high
#D084conventional filtrationcoagulation, sedimentation and filtrationhigh
#D085water treatment plants (WTPs)water treatment plantshigh
#D0861,4-dioxan-2-onea synthesized metabolite of 1,4-dioxanehigh