WR 31: Advances in Consumer Exposure Science: Data, Modelling and Aggregate Exposure Assessment.
26th January 2016, Brussels
In a Nutshell
Brussels, August 2016
To understand and predict health risks posed by exposure to substances it is necessary to understand both the toxic properties and potential exposure to that substance:
Toxic properties x Exposure = Risk
While standardised, internationally accepted methods are available to understand toxic properties, adequate methods and tools to make accurate and robust exposure predictions are not so common. In addition, there is sometimes confusion and misunderstanding about what tools and methods should be applied to predict exposures for specific circumstances, in particular, predicting aggregate consumer exposure to a substance that might be contained in a number of household products.
The Workshop provided the opportunity for experts from industry, academia and the regulatory community to review and discuss the landscape of the various tools and methods available currently to estimate consumer exposures. Also, by using case studies examined the strengths and weaknesses of the various tools and methods for assessing consumer exposures to different classes of substances.
Based on these analyses the Work Shop participants:
- identified best practices guiding the use of existing tools that are best suited for specific applications,
- produced a set of recommendations to reduce variability and improve quality of exposure predictions, and to broaden cooperation between industry, academics and the regulatory community to drive activities improving exposure quality.
A synopsis of the meeting together with recommendations for improving quality and reducing variability in consumer predictions are found in ECETOC Workshop Report no 31: Advances in Consumer Exposure Science: Data, Modelling and Aggregate Exposure Assessment. 26th January 2016, Brussels.
This workshop report summarises a workshop held in Brussels on 26th January 2016 by the ECETOC Human Exposure Data Task Force on the state of the art of consumer exposure assessment science as developed over a period of two years (2013-2015). Over forty exposure experts from industry, academia and regulatory domains came together to: (i) discuss the status of consumer exposure science; (ii) develop consensus on key gaps, and from there, (iii) identify a prioritised research agenda.
Seven presentations provided an overview of (1) The ECETOC Human Exposure Task Force; (2) Robust Exposure Assessment in Refining Risk Assessment; (3) Modelling Total Exposure to Chemicals in Multiple Sources; (4) Presentation of the Task Force’s Landscaping Exercise, summarising available data, sources, models and tools; (5) The case study of phenoxyethanol in household, personal care and cosmetic products; and (6) The case study of solvent use in consumer chemical products. These topics were discussed and debated in detail in two separate discussion sessions. Finally, brainstorm sessions enabled experts to identify consensus on gaps and suggestions on how to move forward.
There was agreement that clear, harmonised guidance on aggregate consumer exposure assessment is required. To this end, delegates from the OECD, JRC, EPA and ECHA offered to discuss future cooperation on this activity within their organisations and to contribute to the Landscaping Document initiated by the ECETOC Task Force. This valuable resource brings together the currently available consumer data, sources, models and tools.
Participants decided that such guidance should include (but not be limited to) the following elements:
- Direction on how to determine the most suitable models and data sources for specific aggregate consumer exposure assessments to include decision trees and problem formulation templates. These should have well-stated and validated (as far as is possible) applicability domains with standardised descriptors recognising the unique factors of each model that determines its fitness for purpose. This could include triggering criteria for higher tier aggregate consumer exposure assessment. It was suggested that the OECD provides a platform that could be used to harmonise these data, models, standards and tools across geographies.
- Open access and/or commercially available databases on consumer information, including consumer use information and product composition (chemical concentration and presence probability data) across domains.
- Direction on how the risk assessor should include a justification narrative (explaining why a particular tool and input data were chosen).
- An agreed process to extrapolate the applicability of exposure data in different contexts as a means of ‘gap filling’ in data sparse situations. For example, best practice exists in the occupational setting (Money and Margary, 2002; ECHA, 2012), which could potentially be extended or adapted to consumer settings. Criteria and internationally accepted rating systems would be needed to evaluate the quality of the data and ensure confidence in such approaches.
- Assessment of how life cycle perspectives could be applied to help determine the nature of exposures.
Finally, the following three suggestions for future research were developed, and will be discussed during future ECETOC and Cefic LRI management meetings:
- Obtaining data on product compositions: this is essential for realistic exposure assessment, particularly when considering aggregate exposure. Without reliable composition data, exposure assessments are based on worst case assumptions giving rise to product restrictions. Questions that need to be answered include: How do we collect, store, share and maintain anonymised product composition data? How do you overcome the barriers to implementing this action across geographies and industry sector groups? Who should lead such an activity?
- Developing an agreed process to extrapolate the applicability of exposure data in different contexts. Ideally, exposure assessments are based on actual measurements of population exposures (workers, consumers, the general population), but for many exposure scenarios, data are hard to find. In these cases, exposure must be estimated using models or by reference to data for analogous substances or situations. Currently there is paucity of advice on the circumstances where analogous data might be applied. By contrast, in hazard assessments, processes have been developed to enable data from various sources to be combined. This could be a starting point for a similar approach in exposure assessment.
- Developing a framework for exposure assessment of exposure data-poor chemicals that includes quality and weight of evidence assessment. Questions that need answers include: Can the principles that are being developed for quality and weight of evidence of hazard assessment be applied for exposure assessment? How do you overcome the barriers to implementing this action across geographies and industry sector groups? Who should lead such an activity?