Presentation on theme: "BIOLOGICAL MARKERS FOR MONITORING EXPOSURE TO MERCURY AND OTHER METALS Mike Inskip Andy Gilman Healthy Environments & Consumer Safety Branch Health Canada."— Presentation transcript:
BIOLOGICAL MARKERS FOR MONITORING EXPOSURE TO MERCURY AND OTHER METALS Mike Inskip Andy Gilman Healthy Environments & Consumer Safety Branch Health Canada
OUTLINE OF PRESENTATION Recent results from Canada –Involvement in Arctic monitoring (AMAP) –Involvement in looking at contaminants in the north of Canada –Laboratory facilities Revisiting Health Canada / Mexico opportunities for cooperation on Mercury analyses (& other metals?)
MERCURY SURVEILLANCE IN CANADIAN POPULATIONS Fish is major source for ALL Canadians Focus on Northern Canada - consumers of traditional diets (fish and marine mammals) Link to ARCTIC MONITORING & ASSESSMENT [AMAP] program (8 countries) Methylmercury is just one of contaminants of concern in northern ecosystems
MERCURY IN MATERNAL BLOOD (ug/L) AMAP Report 2002 (in press) means: Wide range in Canadian Inuit populations for 5 Inuit populations, 6.7, 2.1, 3.4, 3.7, 9.8 for Caucasian: 0.9 Compare with: Alaska, USA: 5.5 and 2.3 Greenland: 50, 12.4, 3.6, 10.5 Russia: 1.4, 1.5, 1.6, 2.7, 2.9, 1.4, 1.2 Finland : 1.4 Faroe Islands 1.2
OTHER METALS IN AMAP COUNTRIES Selenium very variable but elevated in some Greenland communities (marine mammal consumption- whaleskin) Lead in blood higher in some Inuit (lead shot for hunting?) Cadmium elevated in women who smoke (x10) but also diet is a source Trend data - not possible yet as only one or two sampling points But historical records (human hair, animal hair) from 15th and 16th Century vs the 20th century show 3-7 times and 4-6 times elevation for Hg
OTHER HEALTH CONCERNS RE MERCURY & metals in Health Canada Recent evidence on dental amalgams reveal potentially elevated exposure (Legal action underway) Incidence of household thermometer breakages - potential risk to inhabitants if remediation incomplete Mercury in jewelry items and consumer protection issues Hobbyist uses of mercury (and lead) Many others - difficulties in quantifying incidences and risk assessment approaches
MERCURY ANALYSIS - choice of medium for exposure assessment Mercury in blood ug/L Flameless AAS –good indicator of recent methyl-Hg intake from diet Mercury in hair ug/g Flameless AAS –good relationship with Methyl-Hg levels in blood –segmental analysis can show monthly trends Mercury in urine ug/L Flameless AAS –better indicator for inorganic /gaseous mercury exposure (e.g., occupational exposure, chlor alkali mining industries.)
HEALTH CANADA LABORATORIES Inter-laboratory comparisons - participate in international round-robins 30 year involvement with First Nations & Inuit Health Branch, HG surveillance Previous visit by CENAM staff from Mexico to observe analytical methods Involvement in capacity building tasks with other laboratories and countries
DISCUSSIONS ON EARLIER PROPOSAL for Hg monitoring in Zacatecas region Health Canada could : Provide advice on –analytical methods and inter-laboratory QA/QC –recent advances in mercury measurement and exposure assessment Provide advice on biological monitoring approaches and communication strategies. Cover analytical costs of samples at Health Canada laboratories and/or assist scientists from Mexico in technology transfer.
1999 MONITORING PROPOSAL & DISCUSSIONS Select appropriate exposure marker(s) (urine/hair/blood, etc.) and region of Zacatecas Focus on susceptible groups e.g.: –25 women of childbearing age –25 occupationally exposed adults –25 children (e.g., in homes of exposed adults) Adopt appropriate communication strategy in community, create questionnaire & links with all stakeholders and necessary ethical approval.
EXAMPLES OF 1999 UNCERTAINTIES AT THE TIME What were main routes of exposure from Mercury? –Hg vapour? Fish consumption? Dust/air fractions? Were other contaminants (e.g. Pb, Cd) also likely to be present? Where could a control group of people be identified away from the Zacetecana region? What needed to be in place to ensure interested parties were in agreement and were there opportunities for liaison between federal/state /regional/local authorities?
ZACATECAS: THE SITUATION IN new data to assist in refining monitoring proposal What new information is available to help decisions on exposure assessment of population? Are the sources of Hg exposure better understood? Is there any change in the types of advice, analyses or expertise which Health Canada could provide? –More/less samples? –other contaminant monitoring? –Capacity building/scientist exchange?
MESSAGES TO TAKE BACK to Health Canada Listen to reports of new data and findings from Zacatecana region Refine capacity building opportunities –note mutual benefit to all 3 NAFTA parties –Canada receives 50% or more of its Hg deposition from outside its borders –efforts to assist partners reduce emissions will have good pay-back in reduced impact of Hg