Health Canada 2020 - Cadmium drinking water guideline
Health Canada’s 2020 guideline technical document sets a maximum acceptable concentration (MAC) of 0.007 mg/L, or 7 ug/L, for total cadmium in Canadian drinking water measured at the consumer’s tap. The MAC is derived from kidney effects using JECFA’s cadmium tolerable monthly intake, a 20% drinking-water allocation, and adult body-weight and consumption assumptions. The source is especially useful because it connects the health-based value to Canadian monitoring data, analytical methods, treatment performance, and premise-plumbing behavior: cadmium in drinking water is usually low in Canada, but can be elevated where galvanized steel service lines, galvanized premise plumbing, certain well components, cement-mortar lining, or brass fixtures leach cadmium under corrosive-water conditions. Health Canada emphasizes that cadmium control should usually focus on galvanized-material removal and corrosion control, often alongside lead control, rather than relying only on central treatment.
Key numbers
Guideline and toxicology derivation:
| Parameter | Value | Notes |
|---|---|---|
| Canadian drinking-water MAC for cadmium | 0.007 mg/L | Equivalent to 7 ug/L; applies to total cadmium at the tap |
| Sampling basis | Consumer’s tap | Total cadmium, including dissolved and particulate fractions |
| Health Canada adopted tolerable intake | 25 ug/kg bw/month | JECFA 2011 tolerable monthly intake for cadmium |
| Daily intake used in derivation | 0.8 ug/kg bw/day | Monthly value converted to daily basis |
| Allocation factor for drinking water | 20% | Default floor allocation because food is the major cadmium exposure source |
| Adult body weight | 70 kg | Default adult assumption |
| Adult drinking-water intake | 1.5 L/day | Default adult assumption |
| Health-based value calculation | 0.0008 mg/kg-day x 70 kg x 0.20 / 1.5 L/day | Rounds to 0.007 mg/L |
| Critical endpoint | Kidney effects | Low-level kidney effects are the basis for the guideline |
| Cancer basis | Not controlling for drinking-water MAC | Cadmium is carcinogenic by inhalation/occupational routes, but drinking-water-route cancer evidence was not used to derive the MAC |
International comparator values cited by Health Canada:
| Jurisdiction / agency | Drinking-water cadmium value |
|---|---|
| Health Canada | 0.007 mg/L |
| U.S. EPA | 0.005 mg/L |
| Australia | 0.002 mg/L |
| WHO | 0.003 mg/L |
| European Union | 0.005 mg/L |
Canadian occurrence and exposure values:
| Dataset or exposure measure | Reported value | Notes |
|---|---|---|
| Newfoundland and Labrador tap water | 3.5% above DL; range 0.01-0.35 ug/L; mean 0.034 ug/L; median 0.02 ug/L | 4,858 samples |
| Ontario treated/distributed water | 15% above DL; range 0.003-10.0 ug/L; mean 0.16 ug/L; median 0.10 ug/L | 8,251 samples |
| Alberta well water | 0.3% above DL; range 1.0-31 ug/L; mean 13.4 ug/L; median 15.0 ug/L | 1,686 samples; detects only |
| British Columbia Interior Health raw/treated water | 97% above DL; range 0.005-100.0 ug/L; mean 0.56 ug/L; median 0.02 ug/L | 1,180 samples |
| Canada raw-water dataset | 85.6% above DL; range 0.001-95.4 ug/L; mean 0.07 ug/L; median 0.01 ug/L | 18,998 samples |
| Canadian dietary cadmium estimate | 0.30 to 0.83 ug/kg bw/day | Median estimates across age/sex groups, foods sold in Canada 2009-2015 |
| CHMS whole-blood cadmium GM | 0.34, 0.30, 0.34 ug/L | Cycles 1, 2, and 3; approximately 5,000+ participants per cycle |
| CHMS urinary cadmium GM | 0.34 and 0.40 ug/L | Cycles 1 and 2; creatinine-adjusted values 0.42 and 0.37 ug/g creatinine |
Analytical-method and treatment values:
| Topic | Value | Notes |
|---|---|---|
| EPA 200.8 ICP-MS MDL | 0.03 to 0.5 ug/L | Selective-ion monitoring to scanning mode |
| EPA 200.9 graphite-furnace AAS MDL | 0.05 ug/L | Total cadmium method |
| Standard Methods 3113B electrothermal AAS MDL | 0.05 ug/L | Total cadmium method |
| EPA practical quantitation level | 2 ug/L | Below the 7 ug/L MAC |
| Ferric sulphate coagulation/filtration | 96%-99% removal at pH about 8.7-8.8 | Removal dropped to 25%-30% at pH below 7 |
| Alum coagulation | 73%, 65%, and 36% removal at pH 8.0, 7.9, and 6.9 | Demonstrates pH dependence |
| Lime softening | greater than 93%-95% removal in cited studies | High-pH softening conditions |
| Reverse osmosis | 96%-99% removal | Cited feed concentrations 0.18-3.7 mg/L |
| NSF/ANSI 53, 58, and 62 residential devices | 0.03 mg/L influent to 0.005 mg/L maximum effluent | Certification test condition for total cadmium |
| NSF/ANSI 60 and 61 single-product allowable concentration | 0.0005 mg/L | Applies to treatment chemicals and drinking-water-system components |
Premise-plumbing and distribution findings:
| Matrix or plumbing context | Cadmium finding | Notes |
|---|---|---|
| Distribution scale/sediment | median 0.26 ug/g; 10th-90th percentile 0.06-2.8 ug/g | Cadmium found in all scale/sediment samples cited |
| Lead pipe scales | average 6.4 ug/g; range 2.0-308.0 ug/g | Demonstrates cadmium accumulation with lead-bearing scale |
| Stagnant water in galvanized homes | median 0.63 ug/L | Compared with 0.06 ug/L in homes with copper plumbing in the cited dataset |
| Older galvanized plumbing | median 0.8 ug/L | Compared with 0.51 ug/L in newer galvanized plumbing |
| Private systems first-draw samples | mean, median, and p90 below DL of 0.1 ug/L; 0.6% above 5 ug/L | 2,144 samples |
| Brass faucets in stagnation tests | below 0.05 to 10 ug/L | First 24-hour stagnation in cited testing |
Methods (brief)
This is a Health Canada guideline technical document, not a single laboratory sampling paper. The document compiles Canadian occurrence monitoring from provincial and national drinking-water datasets, Canadian food and biomonitoring exposure data, international regulatory values, analytical-method performance summaries, treatment studies, distribution-system and premise-plumbing evidence, and toxicological derivation studies. Health Canada specifies total cadmium at the tap as the compliance basis and notes that digestion conditions matter: methods that do not fully recover particulate cadmium can underestimate total cadmium when particulates are present.
The treatment review covers municipal processes identified by U.S. EPA and the drinking-water literature, including coagulation/filtration, lime softening, ion exchange, reverse osmosis, and adsorption. The guideline stresses that because cadmium is often introduced from plumbing materials rather than source water, system-level control should prioritize removal of galvanized steel, corrosion control, and targeted monitoring in corrosive-water zones. Residential treatment devices certified to NSF/ANSI standards are discussed as a point-of-use option but are not a substitute for correcting system materials where exceedances are caused by plumbing.
Implications
Certification: This source is a regulatory and exposure-context anchor, not a product benchmark pool. The 7 ug/L Canadian MAC, the 5 ug/L residential-device effluent certification value, and the 0.5 ug/L component/material single-product allowable concentration are relevant comparators for water, water filters, and any product category where water is an input or reconstitution matrix. The Canadian monitoring ranges should be kept jurisdiction-specific and drinking-water-specific; they should not be silently pooled with bottled-water, food, or ingredient occurrence distributions.
Courses: The guideline is a useful worked example for distinguishing a health-based value, a regulatory MAC, analytical capability, and treatment feasibility. It also teaches the practical importance of sampling at the tap for metals affected by premise plumbing, rather than assuming treated-water or source-water measurements characterize consumer exposure.
App: Use as Canadian drinking-water guidance for cadmium, with contextual messaging that food is the dominant cadmium exposure source for most nonsmokers but drinking-water cadmium can spike where galvanized plumbing or other cadmium-bearing components contact corrosive water. Any app-facing comparison should preserve the total-cadmium basis and avoid treating total cadmium in water as a substitute for cadmium in food.
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Verification notes
The PDF was read in full from the June 3 manual-fetch folder, including the guideline summary, exposure section, Table 2 occurrence values, analytical methods table, municipal and residential treatment discussion, premise-plumbing section, toxicology derivation, and international comparison text. Page count is 50. No DOI is assigned. The canonical raw file raw/Manual Fetch Kimi /June 3 Folder/drinking-water-quality-guideline-cadmium.pdf and duplicate file raw/Manual Fetch Kimi /June 3 Folder/drinking-water-quality-guideline-cadmium 2.pdf are byte-identical with SHA-256 416a4bcf3442dfaaa938fb9c7ae552d7058b376ee9178ca49dd6e5e569f548aa; the duplicate is recorded in the tracker as a duplicate rather than a second source.
Scope note: the source is a drinking-water guideline and compiles monitoring/treatment evidence. It is not a primary food-occurrence study, not a bottled-water market survey, and not a new residential treatment device test. [[products/water-filters]] is included because the source reports NSF/ANSI residential treatment-device performance criteria for cadmium; it should be treated as context/comparator evidence, not as finished-product occurrence data. Canada drinking-water-guideline and drinking-water-testing pages would be natural future destinations if those page families are created.
Page history
The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.