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Emerging Issues in Industrial Hygiene – The Impact of Biomonitoring Data

Sol Bobst, PhDSenior Scientist

Center for Toxicology & Mechanistic BiologyEXPONENT, Inc.Houston, Texas

sbobst@exponent.comTel: 832-325-5714

GSM: 281-686-6363FAX: 832-325-5799

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Biomonitoring Overview

What is it? Intended Uses Interpretation TLV / BEI Evaluation Process Resources Acknowledgements

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What is Biomonitoring?

“Biomonitoring,” is defined in the environmental public health field as the assessment of human exposure to an environmental chemical via the measurement of that chemical, its metabolites, or reaction product(s) in human blood, milk, urine, saliva, adipose, or other tissue in individuals (in a population).

Needham: Int J Hyg Env Health, 2006

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Why is it important to the Practice of Industrial Hygiene?

Identification

Evaluation

Control

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Current Consensus Biomonitoring Data are being generated and published faster

than regulators and professionals can analyze and interpret them.

There is a need for well defined guidelines for interpreting biomonitoring data.

There is a need to understand how biomonitoring data should be utilized in a risk evaluation framework for regulators and industrial stakeholders.

There is a need to clearly communicate that biomonitoring data do not substantiate a human health risk and disease.

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Intended Uses for Biomonitoring

Provide a metric of exposure for use in risk assessment.

Monitor/Idenitfy exposure trends within a population.

Use available tools to provide the basis for more effective design of approved studies / risk assessments.

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Use in Risk Assessment

Establish & Characterize Exposure / Trends.

Investigate “linkages” between exposure and adverse health effects.

Facilitate Risk Management. ECOTOC Document 44, November 2005

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The Challenge

The Production of Biomonitoring Data, or utility of a Biomonitoring Study, often does not address all of the requirements for rigorous and effective risk evaluation.

What does the data mean? How is it useful? What is inappropriate interpretation?

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Issues in Biomonitoring

Data Quality Interpretation Ethics Transperency Biomonitoring vs. Biomarkers

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Data Quality

Requirements – Must address intended use, but also evaluate potential use

Methodology, Study Design, Calibrations

Technical Quality

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Interpretation of Biomonitoring

Analytical Integrity Standardized Methodology,

(local vs. international standards)

Recovery, Reproducibility

Accounting for false positives/contamination

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Ability to Describe Exposure Requires Toxicokinetics

Routes of Exposure Endogenous Contribution Pharmacokinetics/Pharmacodynamics of

Absorption, Distribution, Metabolism, Excretion Genotoxic Effects Forward or Reverse Extrapolation of Dose

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Exposure – Effect Continuum

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Benefits of Including Biomonitoring Evaluation into Industrial HSE Policy

Enhance Risk Management.

Case by Case evaluation of chemical specific Biomonitoring can result in effective guidance for data development of: Animal testing Methodologies for assessing human exposure IH sampling.

Save Time, Resources, Money.

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Shift in Focus

From External Exposure Concentrations to Internal Dose Estimation.

Future Regulatory Decisions may set exposure guidelines (EPA, OSHA, TCEQ) based on BEI(s), or Biomonitoring / Biomarker indices.

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Biomonitoring Interpretation in Industrial Hygiene

ACGIH Process for Evaluating TLV/BEI

Opportunity for Involvement

http://www.acgih.org/TLV/

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Interpretation

Define Limitations Example – One Person – One Blood Sample – One Test!!!!!

NHANES Study, CDC

Account for Variability – Population Context Age, Gender, Sample Volume, Geographical Location of

Sample

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Biomarker Evaluation is an Important Step in Interpreting Biomonitoring Data

Biomarker vs. Biomonitoring Data Biomonitoring: Arsenic in Hair (Chemical in

Fluid/Tissue/Matrix) Biomarker: DNA Adduct (Metric of Metabolism / Biological

Mechanism)

Measure of Chemical Metabolite in Biological Fluid/Tissue.

Accurate Metric for Understanding External Exposure.

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Biomarker Evaluation is an Important Stepin Interpreting Biomonitoring Data

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Feedback

What Concerns or Issues in Biomonitoring are important to you?

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Public Resources for Biomonitoring

ECOTOC Report NAS Report Other

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ECETOC Report(European Centre for Ecotoxicology & Toxicology of Chemicals)

Guidance for the Interpretation of Biomonitoring Data, Document No. 44, Brussels, November 2005. Establishes Framework for evaluating biomonitoring data

for risk assessment. More Detailed Guidelines on Interpretation Examples: Parabens, Hexachlorobutadiene

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NAS Report Human Biomonitoring for Environmental Chemicals

(NRC – NAS 2006).

Conclusions: There is a need for a consistent rationale for selecting

chemicals for study based on exposure and public-health concerns.

Appropriate Statistical Principles Need to be Applied when sampling populations.

Recommend that biomonitoring program sponsors require planning for communication and evaluation. for any applied use.

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Other

Biomonitoring.info – Environmental Health Research Foundation http://biomonitoringinfo.org/

CDC – National Biomonitoring Program: http://www.cdc.gov/biomonitoring/

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Acknowledgements

Exponent Biomonitoring Team Angelina Duggan Elizabeth Anderson Ben Thomas Louis Bloemen Sanjeev Saraf Martin Barrie

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References Guidance for the Interpretation of Biomonitoring Data, Document No. 44,

Brussels, November 2005, ECOTOC.

Needham, Calafat, Barr “Uses and issues in biomonitoring” Int J Hyg Environ Health 2007 May;210(3-4):229-38. Epub 2006 Dec 8.

Albertini , Bird , Doerrer, Needham, Robison, Sheldon, Zenick. “The use of biomonitoring data in exposure and human health risk assessments.” Environ Health Perspect. 2006 Nov;114(11):1755-62.

Doerrer “Integration of human biomonitoring exposure data into risk assessment: HSEI intiatives and perspectives Int J Hyg Environ Health 2007 210; 247-251

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Report Website Links

NAS Biomonitoring Report - http://books.nap.edu/openbook.php?isbn=0309102723

ECETOC Report -http://www.ecetoc.org/docsharenoframe/netservices/documents/viewpaperpublication.aspx?PortalSource=718&DocID=1058