How to Obtain a Reliable Estimate of Occupational Exposure? Review and Discussion of Models’ Reliability

Abstract

Evaluation and validation studies of quantitative exposure models for occupational exposure assessment are still scarce and generally only consider a limited number of exposure scenarios. The aim of this review was to report the current state of knowledge of models’ reliability in terms of precision, accuracy, and robustness. A systematic review was performed through searches of major scientific databases (Web of Science, Scopus, and PubMed), concerning reliability of Tier1 (“ECETOC TRA”-European Centre for Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment, MEASE, and EMKG-Expo-Tool) and Tier2 models (STOFFENMANAGER® and “ART”-Advanced Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) Tool). Forty-five studies were identified, and we report the complete information concerning model performance in different exposure scenarios, as well as between-user reliability. Different studies describe the ECETOC TRA model as insufficient conservative to be a Tier1 model, in different exposure scenarios. Contrariwise, MEASE and EMKG-Expo-Tool seem to be conservative enough, even if these models have not been deeply evaluated. STOFFENMANAGER® resulted the most balanced and robust model. Finally, ART was generally found to be the most accurate and precise model, with a medium level of conservatism. Overall, the results showed that no complete evaluation of the models has been conducted, suggesting the need for correct and harmonized validation of these tools.

The ECETOC-Targeted Risk Assessment Tool for Worker Exposure Estimation in REACH Registration Dossiers of Chemical Substances—Current Developments

“…Such research should aim at covering the full application scope of the models. In that respect the coverage of the overall performance of TRA is still incomplete as indicated by Spinazzè and colleagues [27] and further studies are welcomed by ECETOC.…”

“…Therefore, published statements such as "the TRA underestimates" or, conversely, "the TRA is conservative" cannot be verified by the partial validation publications available so far but need to be qualified as to which combinations of all parameter used by the program, thus PROC, setting, substance type, volatility or dustiness, and substance application were actually studied. Recently, Spinazzè et al mapped published validation studies against PROCs, but without indicating the distinction between vapor bands of volatile liquids or dustiness bands of handled solids [27]. Regardless, the overview shows several remaining gaps.…”

Exposure Models for REACH and Occupational Safety and Health Regulations

“…For example, the validation of Stoffenmanager ® is now based on almost 7000 measurements, which represents an impressive scientific effort. From a total of 21 studies on external validation, sensitivity and robustness, Spinazzè et al [29] concluded that Stoffenmanager ® tends to overestimate low exposures and underestimate high exposures, but at the same time-by using the recommended 90th percentile-generally guarantees conservative estimates and shows a high degree of robustness. They judged Stoffenmanager ® to be the most robust model for REACH and ART to be the most accurate and precise model, with a medium amount of conservatism.…”

Risk Management Framework for Nano-Biomaterials Used in Medical Devices and Advanced Therapy Medicinal Products

“…To adequately quantify the occupational exposure a multimetric approach (covering different parameters such as particle number, mass and surface-area concentrations, particle mean diameter) using a combination of instruments is recommended [ 42 ]. In the absence of measurements, exposure models for NBMs can be adapted from such models for chemicals and ENMs (e.g., NanoSafer, iEAT, Dermal Advanced REACH Tool—dART, Stoffenmanager Nano) [ 43 , 44 , 45 , 46 ].…”