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Document ID ca-gcdwqgtdn-2017-01-24 Title Guidelines for Canadian Drinking Water Quality: Guideline Technical Document: N-Nitrosodimethylamine (NDMA) URL https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-n-nitrosodimethylamine-ndma/page-4-guidelines-canadian-drinking-water-quality-guideline-technical-document-n-nitrosodimethylamine-ndma.html Jurisdiction /ca Subdomain(s) Drinking water, Water quality standards Language en Status completed Analyzed at 2026-03-18 15:47:55.889798+00:00 Relevance Technical document supporting Canadian drinking water standards for NDMA.

3 Qualitative 38 Quantitative 24 Definitions

Q Qualitative Requirements (3)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Context	Conditions	Confidence
#Q001	monitoring	unknown	recommended	Monitoring of NDMA Exposure from Drinking Water	drinking water	Although drinking water was not identified as the most significant source of exposure to NDMA, they recommended monitoring of exposure from this source.	Reference to the Priority Substances List Assessment Report on NDMA by Environment Canada and Health Canada (2001)	low
#Q002	treatment	treatment	recommended	NDMA Precursor Removal and Disinfection Strategy Modification	drinking water	Consequently, it is suggested that the organic nitrogen precursors be removed or the disinfection strategy used be modified in order to minimize the formation of NDMA without compromising the efficacy of the disinfection process.	Applies when NDMA is present or potentially formed in drinking water due to water treatment (e.g., chloramination)	high
#Q003	administrative	unknown	mandatory	Health Canada Ongoing Monitoring and Review	drinking water	As part of its ongoing guideline review process, Health Canada will continue to monitor new research in this area and recommend any change(s) to the proposed guideline that it deems necessary.	As part of its ongoing guideline review process	medium

P Quantitative Requirements (38)

Req ID	Category	Intent	Legal Status	Name	Subdomain(s)	Limit Type	Limit Value	Context	Conditions	Confidence
#P001	chemical	health	guideline	NDMA	drinking water	MAC	0.000 04 mg/L	The maximum acceptable concentration (MAC) for NDMA in drinking water associated with an excess lifetime cancer risk of 10-5		high
#P002	chemical	health	guideline	NDMA	drinking water	MAC	0.04 µg/L	Alternative unit representation for the proposed MAC of 0.000 04 mg/L		high
#P003	chemical	health	guideline	NDMA	drinking water	unknown	0.1 µg/L	WHO has established a guideline value of 0.1 µg/L for NDMA in drinking water		high
#P004	chemical	health	guidance	NDMA	drinking water	treatment_goal	0.003 µg/L	The California Environmental Protection Agency (EPA) public health goal	Assuming an average weight of 70 kg and drinking water consumption of 2 L/day	high
#P005	chemical	reporting	mandatory	NDMA	drinking water	requirement	0.01 µg/L	The California EPA has set a notification level of 0.01 µg/L for NDMA in drinking water		high
#P006	chemical	health	guidance	NDMA (10-4 risk level)	drinking water	treatment_goal	0.4-1,0 µg/L	Concentration range yielding risk of 10-4		high
#P007	chemical	health	guidance	NDMA (10-6 risk level)	drinking water	treatment_goal	0.004-0,01 µg/L	Concentration range yielding risk of 10-6		high
#P008	chemical	health	guidance	NDMA (California 10-4 risk)	drinking water	unknown	0.3 µg/L	California EPA lifetime theoretical extra cancer risk of 10-4		high
#P009	chemical	health	guidance	NDMA (California 10-5 risk)	drinking water	unknown	0.03 µg/L	California EPA lifetime theoretical extra cancer risk of 10-5		high
#P010	chemical	health	guideline	NDMA (Australia TDI)	drinking water	requirement	4.0-9.3 ng/kg bw per day	Tolerable daily intake (TDI) range determined using a modified benchmark dose approach		high
#P011	chemical	reporting	guidance	NDMA (Estimated levels in Canada)	drinking water	unknown	<= 5 ng/L	Levels of NDMA in drinking water in Canada are generally estimated to be less than or equal to 5 ng/L		high
#P012	chemical	health	guidance	NDMA (10-5 risk level)	drinking water	treatment_goal	0.04-0,1 µg/L	Concentration range yielding risk of 10-5		high
#P013	chemical	health	guidance	TD05 (Female Rats)	drinking water	requirement	34-82 µg/kg bw per day	The dose level that causes a 5% increase in tumour incidence over background in female rats	Lifetime exposure to drinking water	high
#P014	chemical	health	guidance	TDL05 (Female Rats)	drinking water	requirement	18-61 µg/kg bw per day	95% lower confidence limit (LCL) of the TD05 for female rats	Lifetime exposure to drinking water	high
#P015	chemical	health	guidance	TD05 (Male Rats)	drinking water	requirement	35-78 µg/kg bw per day	The dose level that causes a 5% increase in tumour incidence over background in male rats	Lifetime exposure to drinking water	high
#P016	chemical	health	guidance	TDL05 (Male Rats)	drinking water	requirement	29-48 µg/kg bw per day	95% lower confidence limit (LCL) of the TD05 for male rats	Lifetime exposure to drinking water	high
#P017	chemical	health	guideline	Unit Risk (Carcinomas)	drinking water	requirement	5.57 x 10-3 (µg/kg bw per day)-1	Used to determine concentrations yielding specific risk levels for carcinomas	Based on animal to human allometric scaling factor	high
#P018	chemical	health	guideline	Upper Bound Unit Risk (Carcinomas)	drinking water	requirement	1.04 x 10-2 (µg/kg bw per day)-1	95% upper bound on the unit risk for carcinomas	Based on the TDL05	high
#P019	operational	operational	guideline	Average Human Adult Body Weight	drinking water	requirement	70 kg	Used to convert NDMA dose to concentrations in drinking water		high
#P020	operational	operational	guideline	Average Human Drinking Water Exposure	drinking water	requirement	1.9 L/day	Average human exposure via drinking water used for concentration conversion	As indicated by the multiroute exposure assessment	high
#P021	unknown	health	guideline	Essentially Negligible Risk Range	drinking water	treatment_goal	10-5 to 10-6 excess lifetime cancer risk	The level at which increased cancer risk is considered essentially negligible for a carcinogen	Exposed over a lifetime	high
#P022	chemical	health	guideline	Unit Risk (Biliary cystadenomas)	drinking water	requirement	2.28 x 10-3 (µg/kg bw per day)-1	Lower end of calculated unit risk range used to determine concentration ranges for risk levels	Based on animal to human allometric scaling factor	high
#P023	chemical	health	guideline	Upper Bound Unit Risk (Biliary cystadenomas)	drinking water	requirement	3.09 x 10-3 (µg/kg bw per day)-1	95% upper bound of the unit risk for biliary cistadenomas	Based on the TDL05	high
#P024	operational	operational	guideline	Average Adult Weight (WHO Reference)	drinking water	requirement	60 kg	Reference weight used by WHO to establish the 0.1 µg/L guideline value		high
#P025	operational	operational	guideline	Average Water Consumption (WHO Reference)	drinking water	requirement	2 L/day	Reference daily water consumption used by WHO to establish the 0.1 µg/L guideline value		high
#P026	operational	operational	guidance	Average Water Consumption (California EPA Reference)	drinking water	requirement	2 L/day	Drinking water consumption assumed by California EPA for deriving public health goals		high
#P027	chemical	health	guideline	Essentially Negligible Risk Concentration Range	drinking water	treatment_goal	0.004 to 0.04 µg/L	Range of concentrations (4-40 ng/L) considered to present an 'essentially negligible' lifetime cancer risk		high
#P028	microbiological	health	guidance	Lethal Dose (LD50) - Rats	drinking water	unknown	23 to 40 mg/kg bw	Acute oral toxicity after administration to rats	Oral administration	high
#P029	chemical	health	unknown	4-h Median Lethal Concentration (LC50) - Rats	drinking water	unknown	240 mg/m³	Acute toxicity via inhalation for rats	4-h inhalation exposure	high
#P030	chemical	health	unknown	4-h Median Lethal Concentration (LC50) - Mice	drinking water	unknown	176 mg/m³	Acute toxicity via inhalation for mice	4-h inhalation exposure	high
#P031	chemical	health	unknown	Lowest-observed-effect concentration (LOEC) - Inhalation	drinking water	unknown	49 mg/m³	LOEC identified for inhalation in dogs	Dogs exposed to NDMA for 4 h	high
#P032	chemical	health	unknown	Intraperitoneal Lethal Dose (LD50) - Rats	drinking water	unknown	43 mg/kg bw	Acute toxicity following intraperitoneal exposure in rats	Intraperitoneal injection	high
#P033	chemical	health	unknown	Intraperitoneal Lethal Dose (LD50) - Mice	drinking water	unknown	20 mg/kg bw	Acute toxicity following intraperitoneal exposure in mice	Intraperitoneal injection	high
#P034	chemical	health	unknown	Carcinogenicity Bioassay Concentration Range	drinking water	unknown	33 to 16 896 µg/L	Range of concentrations used in the Brantom/Peto carcinogenicity bioassay	Lifetime exposure in drinking water for Colworth-Wistar rats	high
#P035	chemical	health	unknown	Unscheduled Hepatic DNA Synthesis Threshold	drinking water	unknown	0.1 mg/kg bw	Increased unscheduled hepatic DNA synthesis observed in rats	Oral or intraperitoneal administration	high
#P036	chemical	health	guidance	Public Health Goal (PHG) - California EPA (ng/L)	drinking water	treatment_goal	3 ng/L	Alternative unit for California EPA public health goal	Assuming an average weight of 70 kg and drinking water consumption of 2 L/day	high
#P037	chemical	health	unknown	Lethality Threshold - Pregnant Rats	drinking water	unknown	15 mg/kg bw	Single oral doses resulted in lethality of 9.4% of pregnant rats	Day 18 of pregnancy	high
#P038	chemical	health	unknown	Kidney Effect Threshold - Mink	drinking water	unknown	0.2 mg/kg bw per day	Effects in the kidneys observed in mink receiving dose from the diet	Dietary exposure	high

D Definitions (24)

Req ID	Name	Context	Confidence
#D001	LD50s	lethal doses (LD50s)	high
#D002	LC50s	median lethal concentrations (LC50s)	high
#D003	LOEC	lowest-observed-effect concentration (LOEC)	high
#D004	Group 2A	Group 2A, "probably carcinogenic to humans", which means that there is sufficient evidence of carcinogenicity in animals, but human data is limited	high
#D005	TD05	TD05 (i.e., the dose level that causes a 5% increase in tumour incidence over background)	high
#D006	MAC	maximum acceptable concentration (MAC)	high
#D007	TDI	tolerable daily intake (TDI)	high
#D008	essentially negligible	In the context of drinking water guidelines, Health Canada has defined this term as a range from one new cancer above background per 100 000 people to one new cancer above background per 1 million people (i.e., 10-5 to 10-6) exposed to a contaminant at the MAC over a lifetime.	high
#D009	NDMA	N-Nitrosodimethylamine	high
#D010	ppm	parts per million	high
#D011	congestion	excessive blood/fluid content	high
#D012	LCLs	lower confidence limits	high
#D013	TDL05	95% LCL on the TD05	high
#D014	EPA	California Environmental Protection Agency	high
#D015	epicutaneous	dermal	high
#D016	hepatotoxicity	effects in the liver	high
#D017	G → T	guanine to thymine	high
#D018	G:C → A:T	guanine:cytosine to adenine:thymine	high
#D019	intermediate radical	CH3(CH2·)NBN=O	high
#D020	hydroxymethylnitrosamine	HOCH2CH3HBN=O	high
#D021	monomethylnitrosamine	CH3NHN=O	high
#D022	methyldiazonium ion	CH3N+≡N	high
#D023	methylamine	CH3NH2	high
#D024	A:T → G:C	adenine:thymine to guanine:cytosine	high