Exposure Assessment

Exposure assessment is "the process of estimating or measuring the magnitude, frequency, and duration of exposure to an agent, along with the percentage and characteristics of the population exposed. Ideally, it describes the sources, routes, pathways, and uncertainty in the assessment." IPCS, 2004 Glossary of Key Exposure Assessment Terminology.

A hazardous chemical does not pose a risk if the exposure to this chemical is below a safe threshold. Exposure assessment is therefore essential to decide if the identified hazard effectively implies a risk or not. Exposure can be determined via modelling of monitoring. During the exposure assessment, it is important to identify all risk management measures (for modelling or monitoring and input parameters (for modelling) that are relevant). Examples are room ventilation or personal protective equipment that might significantly impact the final exposure values and thus the potential risk that will be determined later.

Adapted from Risk Management of Complex Inorganic Materials, Violaine Verougstraete, 2018

Models

MEASE- Occupational Exposure Assessment Tool for REACH (EBRC&EM, Version 2.0, 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 1^st tier screening tool for the estimation of occupational inhalation and dermal exposure to metal substances and inorganic substances.

Guidance

Framework for Metals Risk Assessment (US EPA, 2007), Chp.4 - Human Health Risk Assessment for Metals (pp.4-3-13)

The Framework for Metals Risk Assessment is a science-based document that addresses the special attributes and behaviours of metal substances and metal compounds to be considered when assessing their human health and ecological risks, including exposure assessment. The document describes basic principles to be considered in assessing exposure and associated 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.

Chp. 4. Human health risk assessment for metals:

4.2 Human Exposure Assessment

4.2.1 Background levels

4.2.2 Bioavailability

4.2.3 Susceptible Populations (Life Stage, Demographics, Pregnancy and Lactation, Concurrent Damage or Disease, Nutritional State, Genetic Polymorphisms and Variability)

4.2.4 Environmental Release, Transport and Fate

4.2.5 Route-Specific Differences in Effects (Inhalation Exposure, Dietary Exposure, Incidental Soil Exposure, Drinking water Exposure, Dermal Exposure)

4.2.6 Integrated Exposure (Modelling)

4.2.7 Biomarkers.

Guidance on the assessment of Occupational Exposure to Metals based on monitoring data (EBRC, EM, 2016)

The aim of this guidance is to address best practices on inhalation monitoring at the workplace.

The guidance covers five aspects:

sampling strategy
sampling equipment
documentation and reporting
data management
data analysis

Also included is further use as calibration data for exposure estimation tools, and a summary of further sources of information.

HERAG- Health Risk Assessment Guidance for Metals- Fact Sheets 1, 2,3,4 (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. These fact sheets were written to reflect the lessons learned from the metal substances risk assessments conducted under the previous EU legislation (2000-2008). 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:

Guidance on Information Requirements and Chemical Safety Assessment - Chapter R.14: Occupational exposure assessment (ECHA) Not metal specific

This generic guidance gives advice to registrants on how to carry out an occupational exposure assessment under EU REACH. REACH requires, according to Article 14(4), exposure assessment and subsequent risk characterisation to be carried out for substances subject to registration, which are manufactured or imported in quantities equal to or greater than 10 tonnes/year, and where the substance fulfils the criteria for any of the hazard classes or categories listed in Article 14(4)2 or is assessed to be a PBT or vPvB. This guidance document describes how to build exposure scenarios and estimate exposures. The guidance also addresses aspects relating to the scope of the assessment, and the assessment workflow. The guidance includes the following sections:

Types and routes of exposure (Section R.14.2)
Assessment workflow (Section R.14.3)
Assessment principles (Section R.14.4)
Exposure determinants (Section R.14.5)
Exposure estimation (Section R.14.6)
Exposure assessment and Applications for Authorisation (Section R.14.7)
Exposure estimation models

The main focus of the guidance is occupational exposure assessment in the context of REACH Registration (i.e. when required by Article 14(4)). However, occupational exposure estimation is also required in the context of applications for authorisation and the information contained in this guidance is, in general, also applicable to the exposure assessment in this context with specific considerations identified in Section R.14.7.

R.14 is a generic guidance applying to all substances under REACH but refers to one metal-specific tool, MEASE.

Presentations

Approaches to Exposure Assessment for Metals (ICMM presentation at APEC, Philippines, 2015)

Case studies

Group A Human Health Case Studies: Mercury Exposure and Essential Metals (ICMM presentation at APEC, Philippines, 2015)

Publications

Risk Management of Complex Inorganic Materials: A practical Guide, (Violaine Verougstraete, 2018) Chp.2,11

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:

General introduction
Sources of Exposure to inorganic complex materials
Mechanisms Underlying Toxicity of Complex Inorganic Materials
Principles of risk Assessment and Management of Complex Inorganic Materials
Main characteristics of relevance for the assessment of complex inorganic materials
Data needs, availability, sources and reliability
Environmental Toxicity assessment of complex inorganic materials
Human Health Toxicity assessment of complex inorganic materials
Specific methodologies/tools to support assessment
Hazard assessment of ores and concentrates
Risk assessment of exposure to inorganic substances of UVCBs during manufacturing (recycling) of metals
Risk assessment for manufacture and formulation of Inorganic Pigments (manufacturing and use)
Risk assessment of alloys (manufacturing, use, end of life)
Emerging tools in the assessment of metals: Current Applicability

Metals Toolbox

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