Limitations and information needs for engineered nanomaterial-specific exposure estimation and scenarios: recommendations for improved reporting practices

Abstract

The aim of this paper is to describe the process and challenges in building exposure scenarios for engineered nanomaterials (ENM), using an exposure scenario format similar to that used for the European Chemicals regulation (REACH). Over 60 exposure scenarios were developed based on information from publicly-available sources (literature, books, and reports), publicly-available exposure estimation models, occupational sampling campaign data from partnering institutions, and industrial partners regarding their own facilities. The primary focus was on carbon-based nanomaterials, nano-silver (nano-Ag) and nano-titanium dioxide (nano-TiO 2 ), and included occupational and consumer uses of these materials with consideration of the associated environmental release. The process of building exposure scenarios illustrated the availability and limitations of existing information and exposure assessment tools for characterizing exposure to ENM, particularly as it relates to risk assessment. This article describes the gaps in the information reviewed, recommends future areas of ENM exposure research, and proposes types of information that should, at a minimum, be included when reporting the results of such research, so that the information is useful in a wider context.

Impact and effectiveness of risk mitigation strategies on the insurability of nanomaterial production: evidences from industrial case studies

“…A minimum set of data that should be reported for all ENM exposure studies has been proposed by a group of scientists concerned with exposure assessment and characterization. 11 This set of data includes, but may not be limited to, both nano-specific (e.g., physicochemical characteristics of airborne released and measured particles, emissivity, and flow dynamics) and non-nano-specific information (e.g., on processes, description of sites, and presence of RM tools put in place). Significantly more research is needed to obtain the comprehensive exposure scenarios and associated exposure estimates for ENMs.…”

Overview of Workplace Exposure to Nanomaterials

“…Two other risk banding models, Stoffenmanager Nano and NanoSafer, include a module to estimate exposure to nanomaterials [171]. This module is based on a conceptual inhalation exposure assessment model for engineered nanomaterials proposed by Schneider et al [172].…”

“…Exposure scenarios have been introduced by the new European chemicals regulation REACH (Registration, Evaluation, Authorization and restriction of CHemicals) [171]. They describe the operational conditions and risk management measures that control the level of exposure to a substance during its lifecycle.…”

A methodology on how to create a real-life relevant risk profile for a given nanomaterial

“…However, in the case of NMs quantitative risk assessment is not feasible due to the fact that presently neither agreed standardised, validated and specific methods for measuring personal exposure (i.e., breathing zone measurements) to engineered NMs are available nor are there validated models providing quantitative estimates of human (worker and consumer) or environmental exposure. 15 The technical limitations of currently available sampling and analytical methods may also raise issues and might not propose sufficient sensitivity to properly assess very low exposure levels. 16 The best available guidance for exposure measurement suggests that in addition to an appropriate characterisation of particle size distribution, measurements should at least encompass an assessment of mass, but where possible also include number and/or surface area concentration.…”