Blood mercury, lead and cadmium levels and determinants of exposure among newcomer South and East Asian women of reproductive age living in Vancouver, Canada.

BACKGROUND: Biomarkers of the reproductive and neuro-developmental toxicants mercury (Hg), lead (Pb) and cadmium (Cd) have been found at higher concentrations in women born outside Canada than in Canadian-born women. We measured blood Hg, Pb and Cd in women ages 19 to 45years living in greater Vancouver (Canada) within five years of their arrival from South Asia (India) or East Asia (mainland China, Hong Kong and Taiwan) and related their biomarker concentration levels with exposures and behaviors since their coming to Canada.

METHODS: Participants were recruited through advertisements in relevant ethnic media, locations and groups. Concentrations of blood Hg, Pb and Cd were analyzed by inductively coupled plasma-mass spectrometry (ICP-Q-MS) and compared with population values. Biomarker concentrations were regressed against exposures and behaviors assessed by culturally-relevant questionnaire.

RESULTS: The study recruited 53 South and 111 East Asian women. Median (95th percentile) blood Pb in South Asians was 1.15 (2.71) μg/dL compared with 1.01 (1.81) μg/dL in East Asians. On the other hand, blood Hg at 2.5 (7.3) μg/L was higher in East Asians compared to 0.20 (0.83) μg/L in South Asians. Blood Cd was also higher in the East Asian group: East 0.53 (1.1) μg/L; South 0.27 (0.82) μg/L. Higher blood Hg was associated with seafood consumption, dental amalgams and traditional remedies; blood Pb with home renovations, sucking on metal jewelry, and cosmetics. Blood Pb and Cd concentrations were inversely associated with dairy consumption.

CONCLUSIONS: Asian women recently arrived in Vancouver had higher blood Hg, Pb and Cd concentrations than same-age Canadian women measured in a national survey. Among South Asian newcomer women of reproductive age, exposure to Cd may continue after arrival. Local exposures to Hg occur through seafood and potentially through ingestion of imported traditional remedies.