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Record information and status
Record ID
Date of creation
2010-03-08 20:33 UTC (andrew.bowers@cbd.int)
Date of last update
2012-05-09 20:29 UTC (dina.abdelhakim@cbd.int)
Date of publication
2012-05-09 20:29 UTC (dina.abdelhakim@cbd.int)

General Information
International Programme on Chemical Safety Safety  Uncertainty and Data Quality in Exposure Assessment - Part 2, Hallmarks of Data Quality in Chemical Exposure Assessment
Organization(s) involved in the publication of this resource
World Health Organization (WHO)
Avenue Appia 20
Geneva 27
Switzerland, 1211
Phone:+41 22 791 21 11
Fax:+41 22 791 3111
Url:World Health Organization (WHO)
  • English
Publication date
Summary, abstract or table of contents

This guidance has been developed as a basis for transparently characterizing uncertainty in chemical exposure assessment to enable its full consideration in regulatory and policy decision-making processes. Uncertainties in exposure assessment are grouped under three categories-namely, parameter, model and scenario-with the guidance addressing both qualitative and quantitative descriptions. Guidance offered here is consistent with other projects addressing exposure in the WHO/IPCS Harmonization Project, including a monograph on IPCS Risk Assessment Terminology, which includes a glossary of key exposure assessment terminology, and a monograph on Principles of Characterizing and Applying Human Exposure Models.

The framework described in this monograph is considered applicable across a full range of chemical categories, such as industrial chemicals, pesticides, food additives and others. It is intended primarily for use by exposure assessors who are not intimately familiar with uncertainty analysis. The monograph aims to provide an insight into the complexities associated with characterizing uncertainties in exposure assessment and suggested strategies for incorporating them during human health risk assessments for environmental contaminants. This is presented in the context of comparability with uncertainties associated with hazard quantification in risk assessment.

This document recommends a tiered approach to the evaluation of uncertainties in exposure assessment using both qualitative and quantitative (both deterministic and probabilistic) methods, with the complexity of the analysis increasing as progress is made through the tiers. The report defines and identifies different sources of uncertainty in exposure assessment, outlines considerations for selecting the appropriate approach to uncertainty analysis as dictated by the specific objective and identifies the information needs of decision-makers and stakeholders. The document also provides guidance on ways to consider or characterize exposure uncertainties during risk assessment and risk management decision-making and on communicating the results. Illustrative examples based on environmental exposure and risk analysis case-studies are provided. The monograph also recommends the adoption of 10 guiding principles for uncertainty analysis. These guiding principles are considered to be the general desirable goals or properties of good exposure assessment. They are mentioned in the text where most appropriate and are supported by more detailed recommendations for good practice. The 10 guiding principles are as follows:

1) Uncertainty analysis should be an integral part of exposure assessment.

2) The level of detail of the uncertainty analysis should be based on a tiered approach and consistent with the overall scope and purpose of the exposure and risk assessment.

3) Sources of uncertainty and variability should be systematically identified and evaluated in the exposure assessment.

4) The presence or absence of moderate to strong dependencies between model inputs is to be discussed and appropriately accounted for in the analysis.

5) Data, expert judgement or both should be used to inform the specification of uncertainties for scenarios, models and model parameters.

6) Sensitivity analysis should be an integral component of the uncertainty analysis in order to identify key sources of variability, uncertainty or both and to aid in iterative refinement of the exposure model.

7) Uncertainty analyses for exposure assessment should be documented fully and systematically in a transparent manner, including both qualitative and quantitative aspects pertaining to data, methods, scenarios, inputs, models, outputs, sensitivity analysis and interpretation of results.

8) The uncertainty analysis should be subject to an evaluation process that may include peer review, model comparison, quality assurance or comparison with relevant data or independent observations.

9) Where appropriate to an assessment objective, exposure assessments should be iteratively refined over time to incorporate new data, information and methods to better characterize uncertainty and variability.

10) Communication of the results of exposure assessment uncertainties to the different stakeholders should reflect the different needs of the audiences in a transparent and understandable manner.
Thematic areas
  • Scientific and technical issues
    • Risk assessment
  • Risk assessment and risk management
Background material to the “Guidance on risk assessment of living modified organisms”
Is this document is recommend as background material for the “Guidance on Risk Assessment of Living Modified Organisms”
Section(s) of the “Guidance on Risk Assessment of Living Modified Organisms” this background material is relevant
Additional Information
Type of resource
  • Report / Review / Fact sheet / Notes
ISBN 978 92 4 156376 5
Publisher and its location
World Health Organization (WHO)
175-page PDF file