Environmental factors associated with blood lead among newcomer women from South and East Asia in the Greater Toronto Area.

BACKGROUND: Newcomers bring with them histories of environmental exposure in their home countries and may have different sources of lead (Pb) exposure compared to other residents of their adopted country. AIMS: To describe past and current factors associated with Pb exposure and blood Pb among South and East Asian newcomer women of reproductive age in the Greater Toronto Area (GTA), Ontario, Canada. METHODS: In collaboration with public health units and community organizations a community-based research model was utilized by recruiting peer researchers to assist in all aspects of the study. Blood samples were taken and phone interviews were conducted. Canadian Health Measures Survey (CHMS) cycles 1, 2, and 3 data was used to contextualize the distribution blood Pb levels. Multiple regression was applied to log-transformed blood lead measurements, using a hierarchical model building process. RESULTS: In total, 211 participants were recruited from Bangladesh, China, India, Pakistan and Sri Lanka. The distribution of the blood Pb varied by country of origin, and higher blood Pb values were found above 75th percentile compared to the CHMS. Distal factors significantly influencing blood Pb concentrations related to life history, such as duration of stay in Canada (RR=0.91; 95% CI 0.86-0.97), living near agricultural fields (RR=0.78; 95% CI 0.62-0.93), and country of origin. Proximal factors with significant contribution were use of cosmetics, traditional remedies, and smoking cigarettes. RECOMMENDATIONS: Different past and current exposures may be important in various newcomer populations, informing international stakeholders, public health agencies, and primary care practitioners to adapt health education and exposure reduction programs to consider pre- and post-migration factors.

Development of a guide to applying precaution in local public health.

PURPOSE: The precautionary principle (PP) urges actions to prevent harm even in the face of scientific uncertainty. Members of Toronto Public Health (TPH) sought guidance on applying precaution. METHODS: We searched five bibliographic databases (yield 60 articles from 1996 to 2009 and 8 from 2009 to 2011) and Google (yield 11 gray literature sources) for material relevant to local public health. From these sources, we extracted questions until saturation was reached (n =55). We applied these questions retrospectively to eight case studies where TPH felt precaution was applied. We ranked questions for their importance in applying precaution. RESULTS: Our final guide included 35 questions in five domains: context, assessment, alternative interventions, implementation, and monitoring and evaluation. Importance rankings varied across cases, but the role of stakeholders in driving precautionary action was consistent. Monitoring and evaluation components could have been strengthened across cases. CONCLUSION: The TPH guide can assist municipal environmental health practitioners in applying precaution in a more transparent manner.

Healthy fish consumption and reduced mercury exposure: counseling women in their reproductive years.

OBJECTIVE: To provide family physicians with a practical, evidence-based approach to counseling women about healthy fish eating. SOURCES OF INFORMATION: MEDLINE was searched for articles published between 1999 and 2008. Most studies described in this article provide level II or III evidence. MAIN MESSAGE: Fish is an important component of a healthy diet for women in their reproductive years owing to the beneficial effects of omega-3 fatty acids on the neurologic development of the fetus. However, some fish species contain considerable methylmercury, which crosses the placenta and has harmful effects on neurobehavioural development. As many jurisdictions have issued fish consumption advisories, which can be confusing, women would benefit from individualized assistance from a trusted source, their family physicians, to clarify the risks and benefits of eating fish. CONCLUSION: We recommend that family physicians counsel women in their reproductive years about healthy choices regarding fish in their diet, and provide appropriate resources.

Risks and benefits of fish consumption for childbearing women.

Pregnant women's fish consumption provides both benefits and risks to the developing fetus. Docosahexaenoic acid (DHA) from fish may enhance fetal neurodevelopment, while methylmercury (MeHg) can have detrimental effects. Dietitians would benefit from information on the frequency with which fish species may be consumed to increase DHA intake among Canadian women of childbearing age, and on minimizing the risks from MeHg, especially for those who consume fish frequently. Eighteen fish species were selected for DHA and mercury analysis from retail markets in the Toronto area. Consumption scenarios using analytical results for these fish species indicate that women of childbearing age can consume nine of 18 fish species every day (14 servings a week) or often (up to four servings a week) and remain below toxicological benchmarks for mercury. Moreover, women can also attain the recommended DHA level by consuming six of those nine fish: four 75-g servings of smelt, porgie, or bluefish a week, or two 75-g servings of milkfish, silver pomfret, or tilapia a day. Our analysis indicates that the DHA level recommended for childbearing women can be attained through fish consumption alone, without the need for supplementation and without posing a risk to the woman (or the fetus) from mercury.

Is house dust the missing exposure pathway for PBDEs? An analysis of the urban fate and human exposure to PBDEs.

Polybrominated diphenyl ether (PBDE) body burdens in North America are 20 times that of Europeans and some "high accumulation" individuals have burdens up to 1-2 orders of magnitude higher than median values, the reasons for which are not known. We estimated emissions and fate of sigma PBDEs (minus BDE-209) in a 470 km2 area of Toronto, Canada, using the Multi-media Urban Model (MUM-Fate). Using a combination of measured and modeled concentrations for indoor and outdoor air, soil, and dust plus measured concentrations in food, we estimated exposure to sigma PBDEs via soil, dust, and dietary ingestion and indoor and outdoor inhalation pathways. Fate calculations indicate that 57-85% of PBDE emissions to the outdoor environment originate from within Toronto and that the dominant removal process is advection by air to downwind locations. Inadvertent ingestion of house dust is the largest contributor to exposure of toddlers through to adults and is thus the main exposure pathway for all life stages other than the infant, including the nursing mother, who transfers PBDEs to her infant via human milk. The next major exposure pathway is dietary ingestion of animal and dairy products. Infant consumption of human milk is the largest contributor to lifetime exposure. Inadvertent ingestion of dust is the main exposure pathway for a scenario of occupational exposure in a computer recycling facility and a fish eater. Ingestion of dust can lead to almost 100-fold higher exposure than "average" for a toddler with a high dust intake rate living in a home in which PBDE concentrations are elevated.