Chemicals

Phthalates in Cosmetic and Personal Care Products: Concentrations and Possible Dermal Exposure

Phthalates are a group of compounds widely used to make plastics more flexible in consumer products, cosmetics, pharmaceuticals, medical devices, and food packaging. Certain phthalates are the subject of concern as they are suspected as having negative effects on reproduction and development. However, most of the research done on phthalates focuses on animal studies, and how this relates to human health is still unclear.

This study measured concentrations of 18 different phthalates in cosmetics and personal care products sold in Canada. Over 250 products (including 98 children products) were analyzed. Results were as follows:

Table 1: Concentrations of 18 different phthalates in cosmetics and personal care products sold in Canada

Phthalate Detected	Detection frequencyTable 1 Footnote 1	Concentration Range (%)
Table 1 footnotes Table 1 footnote 1 products containing phthalates above the detection limits [DL > 0.1 micrograms/gram (μg/g) or 1 x 10 -5 %] Return to table 1 footnote 1 referrer
dimethyl phthalate (DMP)	1/252	0.0072
diethyl phthalate (DEP)	103/252	0.0015 - 2.5
diisobutyl phthalate (DiBP)	9/252	0.0002 - 0.0015
di-n-butyl phthalate (DnBP)	15/252	0.0002 - 2.43
di (2-ethylhexyl) phthalate (DEHP)	8/252	0.0002 - 0.1045

The above results suggest that only DEP and DnBP are present in significant quantity in the test products. From their levels in products and product use patterns, daily exposures in adolescent women were estimated at 0.03, 78, 0.36 and 0.82 for DMP, DEP, DnBP, DEHP, respectively. Toddlers (0.5-4 years) and infants (0-6 months) were exposed to DEP only at 20 and 42 micrograms/kilogram of body weight/day (μg/kg bw/d), respectively.

The overall exposure to phthalates from the use of cosmetic and personal care products was low and, therefore, unlikely to pose health risks to Canadian consumers. Health Canada continues to monitor the research on phthalates, and has put regulations in place to limit exposure. DEHP is listed on Health Canada's Cosmetic Ingredient Hotlist as a prohibited ingredient in cosmetics. In addition, Health Canada has restricted the use of three phthalates (DEHP, DnBP and BBP) in children's toys and child care articles, and three others (DINP, DIDP and DnOP) in those children's products that might be placed in the mouth. Results of the research have been published in the Journal of Environmental Research, 2011 Apr;111(3):329-36.

Thyroid Hormone-Regulated Gene Expression in Juvenile Mouse Liver: Identification of Thyroid Response Elements Using Microarray Profiling and in Silico Analyses

Thyroid hormone (TH), produced by the thyroid gland, is essential for growth, development and metabolism, and alterations in normal TH levels can lead to adverse health outcomes.  By understanding the biological mechanisms that are involved when TH is affected by environmental chemicals, Health Canada will be better able to fulfill its mandate to assess health risks from chemical substances.  In this study, the effects of changes in TH concentrations on gene expression during liver development were examined using mice as a model.  Juvenile mice were treated with chemicals that caused low TH levels, whereas a control group of mice was given TH directly, resulting in high TH levels.  By comparing gene expression in the different groups of mice, genes were identified that appeared to be directly responsive to changes in TH.  Collectively, these results substantially increase knowledge of the genes directly controlled by TH and could ultimately serve as early indicators of exposure to chemicals that alter TH balance for use in toxicological risk assessment.  This study was published in BMC Genomics (2011 Dec 29),12(1):634.

Simultaneous Measurement of Benzo[A]Pyrene-Induced Pig-A and Lacz Mutations, Micronuclei And DNA Adducts in Muta Mouse

Health Canada uses a variety of tests to evaluate the health effects of chemicals present in the environment, and is constantly striving to develop and validate new, more efficient and useful tools for this purpose.  Measuring DNA damage is a common and useful way of evaluating exposure to harmful chemicals, and it can often signal the possibility of an increased risk for cancer.  The tests that are currently available for measuring DNA damage can be expensive and time-consuming, and Health Canada is currently investigating the use of more efficient and quicker tests.  A new test to measure DNA damage directly from blood samples was recently developed; however, it is still in the early stages of validation.  The performance of this new test was studied, using a chemical commonly found in the environment (benzo[a]pyrene (BaP)) that is known to cause DNA damage and cancer.  BaP is found in cigarette smoke and diesel exhaust emissions, and its health effects have been well studied.  The amount of DNA damage detected with the new test was found to be extremely comparable to responses measured using older, more traditional tests.  Routine use of this test could lead to a more cost-effective and efficient method for screening chemicals for their ability to produce DNA damage and their potential to cause cancer, applicable for use in toxicological risk assessment. This study was conducted in collaboration with Litron Laboratories and the Institute of Cancer Research, and was published in Environmental and Molecular Mutagenesis (2011 Dec), 52(9):756-765.

Barhl1 is directly Regulated by Thyroid Hormone in the Developing Cerebellum of Mice

Health Canada conducts research on thyroid hormone disruption in support of its mandate to assess the health risks to Canadians of various chemicals that it is responsible for regulating.  Thyroid hormones are essential for the development of the brain and auditory system.  Exposure to some environmental chemicals during pregnancy may interfere with the normal thyroid hormone balance and lead to abnormally low thyroid hormone levels in the offspring.  In humans, this leads to a lower intelligence quotient if diagnosis and treatment is not initiated at an early stage.  In support of its mandate to assess the risks of various substances to the health of Canadians, Health Canada initiated this study, using animal models, to clarify how thyroid hormones control gene expression during development in order to understand the potential mechanisms involved and the possible involvement of environmental chemicals in this process, as well as to help develop new tools to identify chemicals that exert effects on thyroid hormone.  The results of this study suggest that thyroid hormone deficiency, resulting in impaired brain development, may be caused in part through changes in the gene Barhl1.  This gene is potentially a key component of the biological processes that play a role in the health effects resulting from a thyroid hormone deficiency at birth. Further work will help to determine whether Barhl1 levels could be used as a biomarker for exposure to environmental chemicals that alter thyroid hormone levels. This study was published in Biochemical and Biophysical Research Communications (2011 Nov), 415(1):157-162.

Pulmonary Gene and Microrna Expression Changes in Mice Exposed to Benzo(A)Pyrene by Oral Gavage

Health Canada is responsible for the assessment and management of health risks to Canadians associated with exposure to products and chemicals in the environment.   Benzo[a]pyrene (BaP) is a chemical produced during the incomplete burning of organic material and is also a component of tobacco smoke. BaP is known to cause tumours in experimental animals, and there is also evidence to support an association between BaP exposure and cancer in humans.  Chemical reactions that activate BaP into a form that causes cancer occur in both the lung and liver; however, the lung is the tissue where tumours form, suggesting the response to BaP in lung and liver tissues involves different biological processes.  Health Canada conducted this study to understand why the lungs are more susceptible to cancer than the liver by studying how genes respond in mice exposed to BaP.  The results revealed that some of the differences in cancer susceptibility between the liver and lungs may be due to effects on immune responses in the lung that do not occur in the liver.  This study also suggests that it is also prudent to consider tissues that are not the usual targets of direct exposure to chemicals when assessing their health risks.  These results will be used to fill gaps in knowledge that will help more fully assess the health risks of this priority chemical and mixtures containing this chemical. This study was conducted in collaboration with the Nutrition and Toxicology Research Institute at Maastricht University and was published in Toxicology (2011 Jul 29), 285(3):133-141.

Assessment of Subclinical, Toxicant-Induced Hepatic Gene Expression Profiles after Low-Dose, Short-Term Exposures in Mice

Health Canada is responsible for assessing chemicals used in Canada for their potential impacts on human health.  Determining the responses of all the genes within an organism to chemical exposures is becoming a powerful means to improve the evaluation of potential hazards of chemicals by allowing signatures of toxicity to be developed faster and at a lower cost than when using traditional approaches.  To advance the use of this approach, called toxicogenomics, within a risk assessment context, Health Canada conducted this study to examine responses to four chemicals (PCB126, phenobarbital, isoproterenol and lead acetate) given orally to mice in a descending series of doses, the highest of which was minimally toxic by standard clinical measures.  The results of this study support using changes in genes as early indicators of toxicity, and the use of toxicogenomics data by Health Canada to reduce uncertainties in risk assessment as well as an aide in the design of longer-term toxicity studies of compounds with unknown toxicity.  This study was published in Regulatory Toxicology and Pharmacology (2011 Jun 1), 60(1):54-72.

Polychlorinated Biphenyls (PCBS) Contamination and Aryl Hydrocarbon Receptor (AHR) Agonist Activity of Omega-3 Polyunsaturated Fatty Acid Supplements: Implications for Daily Intake of Dioxins and PCBS

Omega-3 polyunsaturated fatty acid (n-3 PUFA) rich oils are derived from fish and other organisms (e.g., seal, crustacean and flax), and are frequently consumed as nutritional supplements.  Oil derived from fatty fish has been shown to provide substantial health benefits, especially in the prevention of coronary heart disease.  However, these oils are often derived from organisms that are exposed to persistent organic pollutants, including polychlorinated biphenyls (PCBs), dioxins, and dioxin-like compounds.  These compounds are preferentially stored in fatty tissue and accumulate in organisms over time.  Therefore, it is possible that n-3 PUFA supplements could contain a significant amount of these compounds.  To determine levels of two types of contaminants, seventeen oils available throughout Canada purchased from retailers in 2006 or 2007, were analyzed for PCBs and dioxin-like activity.  When consumed at the recommended doses as a supplement to a typical Canadian diet, the tested seal-derived oil was shown to contribute to exceeding the tolerable daily intake for PCBs, and salmon-, tuna-, and sea herring-derived oils were shown to contribute to exceeding the tolerable daily intake of dioxin-like compounds.  The beneficial properties of fish and n-3 PUFA supplements are noteworthy and well documented; however, the results of this study suggest that it is prudent to consume supplements derived from small, cold-water fatty fish.  Further investigations on additional products and multiple sample lots would be necessary to draw firm conclusions about contamination of products available in Canada in order to inform risk management approaches.  This study was conducted in collaboration with the University of Ottawa and was published in Food and Chemical Toxicology (2010 Nov),48(11):3093-3097.

A Survey of the Traditional Food Consumption that may Contribute to Enhanced Soil Ingestion in a Canadian First Nation Community

The inadvertent ingestion of soil is the major pathway for human exposures to non-volatile pollutants in contaminated soils.  Health Canada has an interest in quantifying how much soil people ingest under various circumstances in order to more accurately assess the levels of contaminants that could be ingested through soil; this, in turn, helps to identify the criteria for contaminated site remediation and rehabilitation.  Qualitative soil exposure assessments of people following traditional lifestyles typical of rural or wilderness areas near contaminated sites have proposed soil ingestion rates in the hundreds of milligrams per day.  This study, which is a companion to a human soil ingestion study based on elemental tracers such as aluminum, examined and documented the traditional food consumption activities practiced by an Aboriginal community in the Nemiah Valley of British Columbia.  The survey concluded that a significant portion of the community practiced a lifestyle that may lead to enhanced soil exposure.  The assessment also concluded that some foods, specifically roots, may have substantial amounts of soil adhering to them that would result in ingestion of approximately 33 mg of soil per 100 g serving.  The results of the study will be useful for the exposure assessment portion of human health risk assessments for contaminated sites located in rural or wilderness areas of Canada.  This study was a collaboration with the University of Ottawa and was published in Science of the Total Environment (2012 May 1), 424:104-109.

A Soil Ingestion Pilot Study of a Population Following a Traditional Lifestyle Typical of Rural or Wilderness Areas

The inadvertent ingestion of soil particles is the major pathway for human exposure to non-volatile pollutants at contaminated sites.  Health Canada has been working to understand how much soil people ingest under different circumstances in order to better identify effective site remediation and rehabilitation criteria.  This study assessed soil ingestion in First Nations' individuals who practice traditional lifestyles in a wilderness area of Canada.  There have been no quantitative studies to determine soil ingestion in these populations to date; however, qualitative assessments have proposed ingestion rates in the hundreds of milligrams per day for people following traditional lifestyles typical of rural or wilderness areas.  By measuring fecal levels of elements normally found in soil, the study calculated daily soil ingestion rates for 7 adult subjects living in the Nemiah Valley of British Columbia.  The measured soil ingestion rates were higher than those for previous studies of adults living in urban or suburban environments, but lower than the ingestion rates proposed in the aforementioned qualitative studies.  The results of this research will enhance Health Canada's ability to critically evaluate current regulatory guidelines for contaminated sites, and their applications to people living in rural or wilderness areas of Canada.  This study was conducted in collaboration with the University of Ottawa and the University of Northern British Columbia and was published in the journal Science of the Total Environment (2012 May 1), 424:110-120.