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Metals Toolbox


Risk Characterisation

‘Risk’ is the ‘probability of an adverse effect on man or the environment occurring as a result of a given exposure to a chemical or mixture’ (Van Leeuwen and Vermeire, 2007). A hazard only becomes a risk if exposure exceeds a safe threshold value. Hazard identification and exposure determination have been discussed in previous sections. In a risk assessment, the acute or long-term effects of chemicals on human health and the environment are compared with exposures/emissions so as to estimate the risk associated with the production and use of these chemicals and hence implement risk management measures where needed. The basic principles of characterising hazard, exposure, and risk are similar for complex inorganic materials: there is no risk if the exposure is (sufficiently) below the threshold concentration.

Risk Management of Complex Inorganic Materials, Violaine Verougstraete, 2018


MEASE - Occupational Exposure Assessment Tool for REACH (EBRC, EM, Version 2.00, 2018)

This tool provides estimation and assessment of substance exposures (MEASE) which combines approaches from the Estimation and Assessment of Substance Exposure (EASE) expert system, from the ECETOC targeted risk assessment (TRA) tool and from the health risk assessment guidance for metal substances (HERAG). It aims at providing a 1st tier screening tool for the estimation of occupational inhalation and dermal exposure to metal substances and inorganic substances.

The Multiple-Path Particle Dosimetry Model (MPPD, v 3.04)

The MPPD is a respiratory tract deposition models that can be used for estimating inhalation particles dosimetry for humans, rats and mice. It allows comparisons of deposited doses taking the particle size and other aerosol characteristics into account.  It covers particles, fibers and nanos. While it is not exclusive for metal substances it is particularly relevant to them. The model can be used for risk assessment purposes, research and education.


HERAG - Health Risk Assessment Guidance for Metals (ICMM, factsheets 5,6,7; 2007)

HERAG is a Human Health risk assessment guidance targeting metal substances, therefore taking the metal specificities into account contrary to most of the other risk assessment guidances.

The critical concepts are presented in a series of eight independently reviewed HERAG fact sheets. It is hoped that these latest concepts will enable regulators and scientists to create new or adapt local, national or regional risk assessment systems accordingly.

Fact sheets:

5. Mutagenicity

6. Quality screening procedures for health effects literature

7. Essentiality

Framework for Metals Risk Assessment (US EPA, 2007) Chp 4. Human Health Risk Assessment for Metals (4.4 Risk characterization, pp.4-27)

The Framework for Metals Risk Assessment is a science-based document that addresses the special attributes and behaviours of metals and metal compounds to be considered when assessing their human health and ecological risks.  The document describes basic principles to be considered in assessing risks posed by metal substances and is intended to foster consistency on how these principles are applied across the Agency’s programmes and regions when conducting these assessments.

Content - Risk Characterisation-Key points to consider:

  • Have the qualitative assessment, quantitative assessment, and key uncertainties regarding metals been presented in accordance with EPA guidelines?
  • Do conclusions fully reflect risks in relation to ambient concentrations, essentiality of metals, chemical speciation, and information on human variability in sensitivity?
  • Have assumptions and uncertainties been documented adequately?
  • Have available data on mechanisms of action and metal interactions been fully explored in developing the quantitative assessment?
Guidance for Evaluating the Oral Bioavailability of Metals in Soils for Use in Human Health Risk Assessment (US EPA, 2007)

The purpose of this document is to provide guidance to regional risk assessors on how to assess site-specific oral bioavailability of metal substances in soils for use in human health risk assessments.  Specifically, this guidance document provides: 

1) a recommended process for deciding when to collect site-specific information on the oral bioavailability of metal substances in soils for use in human health risk assessments;

2) a recommended process for documenting the data collection, analysis, and implementation of a validated method that would support site-specific estimates of oral bioavailability; and

3) general criteria that EPA will normally  use to evaluate whether a specific bioavailability method has been validated for regulatory risk assessment purposes.

This guidance is focused on media-specific relative bioavailability and does not address adjustments to default absolute bioavailability values.  Also, this guidance addresses human health risk assessment and may not be necessarily useful for evaluating ecological receptors.  Finally, the guidance document provides information on methodologies for directly assessing bioavailability and does not pertain to indirect methods for predicting bioavailability (e.g. speciation).

Framework for human health risk assessment to inform decision making (US EPA, 2014)

The purpose of this document is to describe a process for conducting human health risk assessments that are responsive to the decision-making needs of EPA. The Framework for Human Health Risk Assessment to Inform Decision Making is further intended to facilitate implementation of existing and future EPA guidance for conducting human health risk assessments and improve the utility of risk assessment in the decision-making process. The Framework addresses recommendations on risk assessment design and utility described in the National Research Council’s (NRC) 2009 report, Science and Decisions: Advancing Risk Assessment, and those put forth in earlier NRC reports (e.g., NRC 1994). This Framework highlights the important roles of planning and scoping, as well as problem formulation, in designing a risk assessment that will serve a specific and documented purpose. In accordance with longstanding Agency policy, it also emphasizes the importance of scientific peer review, as well as public, stakeholder and community involvement.


Bioavailability Adjustments in Human Health Risk Assessment for Metals-Contaminated Sites (ICMM presentation at APEC, Philippines, 2015)
  • Concepts, definitions, and applications
  • Science and Policy
  • Lead
  • Arsenic
  • “Other Metals”
  • Examples of application to metals contaminated site
Human Health Criteria and Standards (ICMM presentation at APEC, Philippines, 2015)

Risk Characterisation and Mixtures Assessment

Case studies

Case Study - Health Risk Assessment of Inorganic Arsenic in the Diet (ICMM presentation at APEC, Philippines, 2015)
Case Study - Using Pharmacokinetic Models in Human Health Risk Assessment for Lead (ICMM presentation at APEC, Philippines, 2015)
Health Risk Assessment of Methyl Mercury in the Diet (ICMM presentation at APEC, Philippines, 2015)
Case Study - Using Bioaccessibility Data for Grouping Metal Compounds (ICMM presentation at APEC, Philippines, 2015)


Risk Management of Complex Inorganic Materials: A practical Guide (Violaine Verougstraete, 2018), Chp4, 5, 6,7.3,9, 11,12 and 13

The aim of this publication is to facilitate the hazard identification as part of risk assessment and management of complex inorganic materials around the world by providing accessible and specific guidance on their assessment. This book explains the main characteristics of inorganic complex materials affecting their hazard and risk assessment and management, including their source and main uses, also covering hazard and exposure assessment, risk characterisation and risk management.

It is an essential reference for regulators involved in risk assessment and risk management, industry experts charged with compliance of chemicals management programme requirements, consultants preparing chemicals management files for companies and regulators, and academics involved in research on complex inorganic materials.

Table of Contents:

  1. General introduction
  2. Sources of Exposure to inorganic complex materials
  3. Mechanisms Underlying Toxicity of Complex Inorganic Materials
  4. Principles of risk Assessment and Management of Complex Inorganic Materials
  5. Main characteristics of relevance for the assessment of complex inorganic materials
  6. Data needs, availability, sources and reliability
  7. Environmental Toxicity assessment of complex inorganic materials
  8. Human Health Toxicity assessment of complex inorganic materials
  9. Specific methodologies/tools to support assessment
  10. Hazard assessment of ores and concentrates
  11. Risk assessment of exposure to inorganic substances of UVCBs during manufacturing (recycling) of metals
  12. Risk assessment for manufacture and formulation of Inorganic Pigments (manufacturing and use)
  13. Risk assessment of alloys (manufacturing, use, end of life)
  14. Emerging tools in the assessment of metals: Current Applicability
Human risk assessment of heavy metals: principles and applications (Dorne, Jean-Lou & Kass, George E. N. & Bordajandi, Luisa & Amzal, Billy & Bertelsen, Ulla & Castoldi, Anna & Heppner, Claudia & Eskola, Mari & Fabiansson, Stefan & Ferrari, Pietro & Scaravelli, Elena & Dogliotti, Eugenia & Fürst, Peter & Boobis, Alan & Verger, Philippe. (2011). Human risk assessment of heavy metals: principles and applications. Metal ions in life sciences. 8. 27-60.)

Last page update: 2 September 2020