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!