Many heavy metals are not acceptable as ingredients in cosmetic products sold in Canada as they may cause injury to the health of the user, which is in contravention of the general prohibition found in section 16 of the Food and Drugs Act. Yet they may still be found in cosmetics as impurities due to the persistent nature of these substances and the fact that they are found in the natural environment. The purpose of this guidance is to determine and communicate appropriate limits of these impurities in cosmetic products. The focus is on the heavy metals with known significant toxicological properties: lead, arsenic, cadmium, mercury and antimony.
This document is not intended to substitute for, supersede or limit the requirements under the legislation. In case of any discrepancy between this summary and the legislation, the legislation will prevail. In addition, other laws, whether federal, provincial or territorial, may also apply to the products that are covered by this guidance document.
Heavy metals are found naturally in the environment in rocks, soil and water, and may therefore be found in pigments and other raw materials in all industries including the cosmetics industry. Some of these metals have been used as cosmetic ingredients in the past. Examples include the preservative thimerosal (mercury), the progressive hair dye lead acetate and a number of tattoo pigments such as red cinnabar (mercuric sulfide).
The Government of Canada has implemented numerous measures to reduce the amount of heavy metals to which Canadians are exposed, including not allowing their intentional use in cosmetics. Lead, arsenic, cadmium, mercury, antimony and chromium are heavy metal ingredients that are listed as prohibited on the Cosmetic Ingredient Hotlist. The Cosmetic Ingredient Hotlist is an administrative tool to communicate to manufacturers and others that certain substances may cause injury to the health of the user, which is in contravention of the general prohibition found in section 16 of the Food and Drugs Act.
Given that the issue of heavy metals as deliberate cosmetic ingredients has been addressed, attention turns to the presence of these substances as impurities. The metals of primary toxicological concern in cosmetics are lead, arsenic, cadmium, mercury and antimony. The toxicity of these substances, as well as recommended impurity limits for certain types of products, is outlined below.
Heavy metals are naturally occurring, are present in the environment and can make their way in trace quantities into raw materials. These substances end up in the products we consume and use every day. Dermal exposure is expected to be the most significant route for cosmetic products since the majority of cosmetics are applied to the skin. Dermal absorption of heavy metals is typically low, with absorption of individual elements influenced by a number of factors including physical-chemical properties of the mixturesFootnote 1. Oral exposure can occur for cosmetics used in and around the mouth, as well as from hand-to-mouth contact after exposure to cosmetics containing heavy metal impurities. Inhalation exposure is expected to be negligible.
The toxicological properties of lead, arsenic, cadmium, mercury and antimony are described below and impurity limits derived for other products are identified. These other impurity limits encompass a variety of products with exposure scenarios that may differ significantly from cosmetics, and it would not necessarily be appropriate for cosmetics to have a similar heavy metal impurity limit. Health Canada's recommended impurity limits for cosmetic products are listed in section 4 of this document.
Lead exerts adverse effects on numerous organs and systems including the central nervous system (CNS), the kidneys and on the hematopoietic (blood forming) system. Exposure to lead is typically greater in children, who are also more susceptible to the effects of lead than adults. Children are particularly at risk for the subtle adverse effects of chronic low-dose lead exposure, as are pregnant women/fetuses. Children absorb about 50% of ingested leadFootnote 2. The identification of causal relationships between exposure and effects is complicated by the delay between the time of lead exposure and the onset of effectsFootnote 3,Footnote 4. Dermal absorption of inorganic lead has been demonstrated in animals and human subjects; however, few studies have provided quantitative estimates of dermal absorption and the contribution of the dermal intake to lead body burdenFootnote 2. Inorganic lead crosses the skin less readily with a low permeability co-efficient of about 10-4 cm/hour. Exposure to lead from cosmetics previously occurred from use of progressive hair dye preparations containing lead acetateFootnote 4; however, lead acetate is now not acceptable in cosmetic products in Canada.
The Guidelines for Canadian Drinking Water Quality recommend a lead Maximum Acceptable Concentration (MAC) of 0.010 mg/L (0.010 ppm) of waterFootnote 5. In the US, acceptable oral intake of lead impurities in candy is 0.1 ppmFootnote 6. For products licensed under the monograph stream of the Natural Health Product Regulations made under the Food and Drugs Act, there is a limit for lead impurities of 10 ppm in products applied to the skinFootnote 7.
Arsenic exerts adverse effects due to a pronounced affinity for skin and keratinizing structures including the hair and nails. Therefore, symptoms of acute overexposure include a variety of skin eruptions, alopecia and characteristic striation of the nailsFootnote 3. Arsenic does not act as a sensitizer, due to poor skin penetrating ability of its naturally occurring compoundsFootnote 3. The health effects of arsenic in humans vary depending on the compound and form. Metallic arsenic is not absorbed by the gastrointestinal tract and does not have any known adverse health effectsFootnote 8. Carcinogenicity has been observed only in its inorganic formFootnote 3. Inorganic arsenic compounds are more acutely toxic than environmentally occurring organic arsenic (for example dimethylarsinate). Dermal uptake is expected to be very limited. One study predicted that dermal exposure to arsenic may contribute less than 1% of the exposure from ingestionFootnote 9.
The recommended MAC for arsenic in drinking water is 0.01 mg/L (0.01 ppm) in CanadaFootnote 8. The United States Food and Drug Administration (US FDA) limit for arsenic in certain colorants is <3 ppmFootnote 10. The United States Environmental Protection Agency (US EPA) has established an oral reference dose (RfD) of 0.3 µg/kg bw/day for arsenicFootnote 11.
Cadmium is classified as a human carcinogen by the National Institute for Occupational Safety and Health (NIOSH)Footnote 3. Absorption of cadmium through the skin is low (0.5%) and would be of concern only in situations where concentrated solutions would be in contact with the skin for several hours or longer. Cadmium binds to epidermal keratin when applied topically, thus explaining the limited dermal absorption observed in vitroFootnote 3. However, significant dermal exposure as could occur in an occupational setting can cause irritant dermatitisFootnote 3.
The literature on the health effects of mercury is extensive. Most of the literature focuses on effects following inhalation exposure to metallic mercury vapours and oral exposure to inorganic and organic mercury compounds. There is limited information on adverse effects following dermal exposure to ointments and creams that contain inorganic mercury compounds.
Various forms of mercury are toxic. The form of mercury plays a role in how much is absorbed via dermal or oral routes. Organic (methyl) mercury is of greater concern than inorganic mercury; however, all forms of mercury are absorbed through the skin and mucosaFootnote 3, and dermal exposure can result in systemic toxicity. For the general population, the major route of mercury exposure is dietary intakeFootnote 2. Mercury compounds may cause allergic reactions, skin irritation, or adverse effects on the nervous systemFootnote 13. Clinical symptoms of overexposure to mercury include tremors, weakness, memory loss, dermatitis and impaired kidney functionFootnote 4, with the form of mercury typically determining the specific symptoms.
The Guidelines for Canadian Drinking Water Quality recommend a MAC of 0.001 mg/L (0.001 ppm) for mercuryFootnote 5. Health Canada has established a limit of 0.5 ppm mercury in most commercial fishFootnote 14. The World Health Organization (WHO) has established a provisional tolerable daily intake of 2 µg/kg bw/day for total mercury and a provisional tolerable weekly intake of 1.6 µg/kg bw for methylmercuryFootnote 15. The US FDA limits mercury impurities in some colourants to <1 ppmFootnote 10. Thimerosal is acceptable for use as a preservative in eye cosmetics in the US with a limit of 65 ppm, provided that no other effective and safe preservative is availableFootnote 13.
Overexposure to antimony and its compounds can adversely affect the skin, lungs, cardiovascular system and liver. Because antimony is found naturally in the environment, the general population is exposed to low levels, primarily in food, drinking water, and air. Average intake of individuals was estimated to be about 5 µg of antimony per dayFootnote 16. Dermal absorption of antimony has not been well studied.
The WHO provisional tolerable daily intake for antimony is 6 µg/kg bw/dayFootnote 17. The Guidelines for Canadian Drinking Water Quality recommend a MAC of 0.006 mg/L (0.006 ppm) for antimonyFootnote 5.
Other metals (for example, selenium, barium and chromium) may be present as impurities in cosmetic products; however the toxicological properties and corresponding risk associated with these substances are considered less significant than for lead, arsenic, cadmium, mercury and antimony. Accordingly, impurity limits in cosmetics have not been developed for these metals.
Acceptable limits for heavy metals vary according to:
Assessment of dermal absorption by a single component in a cosmetic product is complex and depends on factors such as the concentration in the product, the amount of product applied, the length of time left on the skin and the presence of emollients and/or penetration enhancers in the cosmetic productFootnote 18. Given this complexity, and the lack of well-conducted dermal absorption studies incorporating these factors, determination of heavy metal limits in cosmetics based on human health risk alone is a challenge.
There are currently no international standards for impurities in cosmetics. Limits have been established in GermanyFootnote 19. Rather than taking a risk-based approach, the German limits are based on levels that could be technically avoided. Thus, heavy metal impurities were limited to anything above normal background levels.
The German federal government conducted tests to determine background levels of heavy metal contents in toothpastes and other cosmetic products (note that in Canada, most toothpastes are classified as natural health products). Based on their studies, it was determined that heavy metal levels in cosmetic products above the values listed below are considered technically avoidableFootnote 19:
In addition, following a survey of its member companies, the German Industrial Association for Personal Care and Detergents Inc. confirmed that heavy metal contents in toothpastes are at least a decimal power lower than for other cosmetic productsFootnote 19. Therefore, the Commission for Cosmetic Products at the federal Ministry of Health in Germany concluded that the following values are the maximum acceptable concentration for toothpastes:
In 2010, the German government concluded that the recommended limits could be lowered, as evidenced by on-going monitoring of cosmeticsFootnote 20.
Health Canada has taken a similar approach in the establishment of heavy metal impurity limits, as the Department has always maintained that impurities in cosmetics should be reduced to the extent that is technically feasible. A review and analysis of the results of heavy metal testing conducted in the Health Canada Product Safety Laboratory on a number of cosmetics sold in Canada lead to the determination of limits in section 4 of this document. Furthermore, comparison of conservative estimates of exposure to Canadians from use of cosmetics with the established tolerable intakes demonstrated that these levels provide a high level of protection to susceptible subpopulations of consumers (for example children).
It is acknowledged that heavy metal impurities in cosmetic products are unavoidable due to the ubiquitous nature of these elements, but should be removed wherever technically feasible. Heavy metal impurity concentrations in cosmetic products are seen to be technically avoidable when they exceed the following limits:
These levels are based on cosmetic products sampled in Canada and are in line with acceptable levels of impurities in other program areas. In addition, comparison of exposure to Canadians from use of cosmetics and the established tolerable intakes for these metals demonstrated that these limits provide a high level of protection to susceptible subpopulations of consumers (for example children).
It is important to note that occurrences of heavy metals above these limits will be evaluated on a case-by-case basis. Products with values above these limits may undergo an assessment to determine the level of risk posed by the product, which would then determine the appropriate enforcement action.
It is the manufacturer's responsibility to make sure that the finished cosmetic product contains as few heavy metal impurities as possible so that it does not exceed the limits set out above. According to section 16 of the Food and Drugs Act, manufacturers must ensure that products are safe and do not pose a risk to consumers. Health Canada may request information on heavy metal test results for a cosmetic product if a risk is suspected. It is therefore in the manufacturer=s best interest to have the information readily available. Health Canada will take action as deemed appropriate for products that contain heavy metals beyond the limits mentioned above. Manufacturers must make sure that their products, and the ingredients used in the manufacture of their products, are of high quality.
Sainio, E., Jolanki, R., Hakala, E., and Kanerva, L. (2000). Metals and arsenic in eye shadows. Contact Dermatitis 42 (1) , pg. 5-10.
US Department of Human and Health Services. Public Health Services. Agency for Toxic Substances. Toxicological Profile for Lead. August, 2007.
Guy, R., Hostynek, J.J., Hinz, R.S. and Lorence, C.R. Metals and the Skin: Topical Effects and Systemic Absorption. New York, New York. 1999.
Hostynek, J.J. Lead, Manganese and Mercury: Metals in Personal-Care Products. Cosmetics and Toiletries Magazine. Volume 116, no. 8. August, 2001.
Health Canada. Guidelines for Canadian Drinking Water Quality - Summary Table. December, 2010.
United States Food and Drug Administration. Lead in Candy Likely To Be Consumed by Small Children. November, 2006.
United States Food and Drug Administration. Environmental Assessment and Risk Analysis Element, White Paper Summary. January, 2003.
Hostynek, J.J. Toxic Potential from Metals Absorbed Through the Skin. Cosmetics and Toiletries Magazine. Volume 113, pg. 33-42. January, 1998.
Bundesgesundheitsblatt (Federal Health Journal, Germany), 28, 1985, Nr. 7, 216.
Gesundheitlicher und wirtschaftlicher Verbraucherschutz (Federal Office for Consumer Protection and Food Safety, Germany). 2010.
The impurity limit for mercury has been amended from 3 ppm to 1 ppm as per the Minamata Convention on Mercury signed by Canada on October 10, 2013