7.1 St Amand
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Transcript of 7.1 St Amand
Interpreting Population Level Biomonitoring Data in a Risk-Based Context: A Canadian Perspective
Annie St-Amand1, Kate Werry1, Andy Nong1, Sean M. Hays2, Lesa L. Aylward2
1Healthy Environments and Consumer Safety Branch, Health Canada; 2Summit Toxicology LLP
September 10, 2013
Survey Parameters• Cross‐sectional survey design• Ongoing: 2007‐2009 (Cycle 1), 2009‐2011 (Cycle 2), 2012‐2013 (Cycle 3 –data collection in progress)
• National estimates for general population:N= 5600‐6400
• Ages 3‐79 years (3‐5, 6‐11, 12‐19, 20‐39, 40‐59, 60‐79)
• Health questionnaire – home interview• Direct measures (blood/urine)– mobile clinic
Population Biomonitoring Data: Canadian Health Measures Survey
Interpretation Tools
“Safe” human dose RfD, TDI: mg/kg-d
Human urine/blood level
BE: µg/L
Hum
an P
harmacokinetics
Human (equivalent) Point of Departure POD: mg/kg-d
Human urine/blood level
BEPOD: µg/LUncertainty
Factors
UncertaintyFactors
BE - Concentration of biomarker that is consistent with existing exposure guidance or reference values such as RfDs, TDIs, etc (Hays et al., 2007).
Biomonitoring Equivalents (BE)
Source: LaKind et al., 2008
Hazard Quotient (HQ)
HQ = [ Biomarker ] BE
HQ > 1 indicates biomonitoring data exceeds exposure guidance
value
Mediumpriority
Lowpriority
Highpriority
BEPOD
BE
Increasing priority for follow
-up
One Chemical Many Chemicals
Screening of Biomonitoring Data
HQ Screening: Persistent ChemicalsCHMS 2007‐11
CadmiumCHMS 2009‐11 (urine)
High
Medium
Low
BEPOD4.6 µg/L
BE 1.5 µg/L
HQ Screening: Short‐lived Chemicals CHMS 2009‐11 (urine)
10
Inorganic Arsenic: DMA + MMA(µg As/L urine)
High
Medium
Low
BEPOD16 µg/L
BE 5.8 µg/L
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
Arsenic (6-79 years) DDT (20-79 years) HCB (20-79 years)
Can
cer
Ris
k
Estimated Cancer Risk Levels CHMS 2009‐11
Discussion
• HQs < 1 for majority of biomarkers– suggest exposure levels are below existing
guidance values• HQs > 1 at upper bound of the CHMS
population distributions for inorganic arsenic and cadmium.
• BEs do not represent diagnostic criteria • BEs are interim values (screening)
Conclusion
• Cadmium and inorganic arsenic: more detailed examinations required
• Useful for prioritization effortswww.health.gc.ca/biomonitoring
Thank you!