Human Exposure to Environmental Chemicals
The Statistics Canada Agency and the US Centers for Disease Control and Prevention (CDC) both published results of their respective national surveys about human exposures to environmental chemicals in the summer 2010.
Canadian Health Measures Survey (CHMS): BPA, Lead, Mercury and Cadmium Blood Levels in Canadians
The Canadian Health Measures Survey (CHMS) was conducted by Statistics Canada from 2007 to 2009 and included other governmental department partners such as Health Canada and the Public Health Agency of Canada. The CHMS is the largest ever direct health measures survey done nationally in Canada; it was undertaken to assess the levels of various environmental chemicals. Blood and urine samples were collected from a representative number of individuals and tested for their amounts of various environmental chemicals. The survey summary included concentration estimates for Bisphenol A (BPA) and heavy metals (lead, mercury and cadmium). |
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Full Report available
Health Fact Sheets
Summary of key findings:
Lead
- Blood lead concentrations were considerably lower than measures obtained 30 years ago (1.34 microgram/deciLitre in 2007-2009 versus 4.79 micrograms/deciLitre in 1978 among Canadians aged 6 to 79 years).
- From 2007 to 2009, less than 1% of Canadians had a blood lead concentration above 10 micrograms/deciLitre (an arbitrary intervention level established for adults as a precautionary measure due to possible adverse health effects).
- Higher concentrations of lead in the blood (after controlling for age group and sex) were associated with: 1) lower household income; 2) being born outside Canada; 3) living in a dwelling that was at least 50 years old; 4) individuals who are current or former smokers; and 5) individuals who consume alcohol at least once a week.
BPA
- BPA is an industrial chemical used in polycarbonate plastic manufacturing to create food containers and water bottles. It is also used in epoxy resins for the protective linings of canned food and beverage containers. There are no guidance values established in Canada for urinary or blood measures for BPA.
- 91% of Canadians had detectable concentrations of BPA in their urine which is similar to results of the NHANES survey in the US where 93% of the population had detectable BPA. Due to the short-half life of orally ingested BPA it suggests that there is a continuous and extensive exposure of virtually the entire North American population to BPA.
- The mean urinary BPA concentration was 1.16 micrograms/Litre and this value is similar to other reference population studies where urinary BPA was detected at a concentration of 1 to 3 micrograms/Litre).
- The highest concentrations of BPA in urine based on volume were seen in teens aged 12 to 19 years; males also had higher concentration than female in general.
- After adjusting for confounding variables (age, sex, time of urine collection, creatinine concentrations), there were no associations between BPA and household education, household income, country of birth, or Body Mass Index (BMI).
- A single urine sample that is tested, such as was collected in the CHMS study may reflect very recent exposures and may not be indicative of the average BPA exposure of any other individual.
Mercury
- Methylmercury constitutes most of the mercury exposure of the general population. The main exposure route for humans to methylmercury is from fish and seafood consumption.
- Blood mercury was detected in 88% of Canadians between 6 and 79 years old.
- Results indicate that the geometric mean blood mercury level of Canadians was 0.76 micrograms/Litre which indicates that less than 1% of Canadians aged 20 to 79 had total mercury concentrations above the current Health Canada blood guidance value of 20 micrograms/Litre.
Cadmium
- Cadmium is a heavy metal classified as a carcinogen by the International Agency for Research on Cancer (IARC). The main exposure routes for cadmium include diet, drinking water, occupational exposure, and cigarette smoking.
- The geometric mean blood concentration of cadmium was 0.35 micrograms/Litre. Approximately 98% of those tested had levels above the limit of detection of 0.04 micrograms/Litre. However, no Canadian blood cadmium guidance value has been established for the general population. Occupational exposure guidance levels exist but they are not applicable to the general population.
- The mean blood cadmium concentrations in Canadians were found to be similar to those of the general population of the US and Germany, and the non-occupationally exposed population in the Quebec City region.
A series of articles were published in 2007 by Statistics Canada on the development of the Canadian Health Measures Survey (CHMS). Five thematic research papers were published on:
The National Report on Human Exposure to Environmental Chemicals (Fourth Report)is a complete assessment of the US population’s environmental exposure to various chemicals. This National Report describes exposure data for 212 environmental chemicals for the civilian, non-institutionalized US population. Data on 75 new chemicals which had never been measured before in the US population and new results from National Health and Nutrition Examination Survey (NHANES) 2005–2006 data were made available including:
• acrylamide and glycidamide adducts;
• arsenic species and metabolites;
• environmental phenols, including bisphenol A (BPA) and triclosan;
• perchlorates;
• perfluorinated chemicals;
• polybrominated diphenyl ethers;
• volatile organic compounds; and
• some additions to chemical groups previously measured.
The full report and executive summary are available on the CDC website.
Additional information on human biomonitoring, BPA, lead, mercury and cadmium, including their health effects is available at:
Publications
Boogaard PJ, Hays SM, Aylward LL. Human biomonitoring as a pragmatic tool to support health risk management of chemicals - Examples under the EU REACH programme. Regul Toxicol Pharmacol. 2010 Oct 7. Epub ahead of print
Link to Abstract
Bose-O'Reilly S, McCarty KM, Steckling N, Lettmeier B. (2010). Mercury exposure and children's health. Curr Probl Pediatr Adolesc Health Care. 40(8):186-215.
Link to abstract
Clayton EM, Todd M, Dowd JB, Aiello AE. The Impact of Bisphenol A and Triclosan on Immune Parameters in the US Population, NHANES 2003-2006. Environ Health Perspect. 2010 Nov 9. Epub ahead of print
Link to abstract
Crinnion WJ. (2010). The CDC fourth national report on human exposure to environmental chemicals: what it tells us about our toxic burden and how it assist environmental medicine physicians. Altern Med Rev. 15(2):101-9.
Link to abstract
Genuis SJ, Birkholz D, Rodushkin I, Beesoon S. Blood, Urine, and Sweat (BUS) Study: Monitoring and Elimination of Bioaccumulated Toxic Elements. Arch Environ Contam Toxicol. 2010 Nov 6. Epub ahead of print
Link to abstract
Krishnan K, Gagné M, Nong A, Aylward LL, Hays SM. (2010). Biomonitoring Equivalents for bisphenol A (BPA). Regul Toxicol Pharmacol. 58(1):18-24.
Link to abstract
Lakind JS, Naiman DQ. (2008). Bisphenol A (BPA) daily intakes in the United States: estimates from the 2003-2004 NHANES urinary BPA data.J Expo Sci Environ Epidemiol. 18(6):608-15.
Link to abstract
Ruiz P, Mumtaz M, Osterloh J, Fisher J, Fowler BA. (2010). Interpreting NHANES biomonitoring data, cadmium. Toxicol Lett. 198(1):44-8.
Link to abstract
Ye X, Zhou X, Needham LL, Calafat AM. In-vitro oxidation of bisphenol A: Is bisphenol A catechol a suitable biomarker for human exposure to bisphenol A? Anal Bioanal Chem. 2010 Nov 9. Epub ahead of print
Link to abstract
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