Background
A considerable focus has recently been given to developing a structured approach to how available biomonitoring data should be interpreted. (ECETOC, NAS). All framework concepts identify the need for some form of 'guidance values' to assist in the overall interpretation process. While many guidance values are available in the occupational setting (most notably the BEIs® of the ACGIH and the BAT and EKA values of the DFG), few guidance values have been developed for public health use. A well-defined process exists for the establishment of occupational values, which involves drawing on all available information sources (especially human), including suitable modelling of substance metabolism and kinetics, in order to derive appropriate guidance values. As a consequence, those values that are available tend to be for 'data rich' substances.
Because risks do not only result from exposures to data rich materials, in the workplace, tiered strategies have recently been developed for evaluating chemical health risks. These strategies utilise a range of different forms of guidance values (of different levels of confidence, dependent on their intended purpose and/or available supporting information quality/integrity) that account for the extent to which effects data are available to support any substance. The strategies (most notably the UK COSHH Essentials approach) have been shown to offer considerable advantages over those that have historically relied on 'fully developed' guidance values (termed OELs in the workplace).
This project aims to draw on the recent workplace experiences and to evaluate whether a comparable strategy can be developed for application in the public health setting. The project clearly aligns with the ACC sponsored activity that seeks to address Biological Equivalents. It is envisaged that the project would define classes of BGVs (and their basis etc), covering individual substances and/or groups of substances, which would then be tested against 'model' substances and/or classes of material. This could include ”natural” substances to gain a perspective on the relationship of biomonitoring endpoints to actual exposure scenarios. The framework would then be used to stimulate broader discussion and to help focus and direct supporting industry product stewardship activities.
Objectives
Define the core considerations necessary to establish biological guidance values (BGVs) for application in the public health contexts. Considerations within such a proposal include:
- Determine the extent to which different qualities of BGV may be necessary for different substances (or groups of substances) within the broader context of tiered approaches to evaluating risk
- The form or metric that the BGV should take in relation to the target population (e.g. probability distributions rather than points)
- define the circumstances where a BGV (of whatever type) is warranted
- the choice of analyte, media and sampling protocol
- the suitability of likely REACH data to enable the establishment of different types of BGVs e.g. the kinetics information arising from Annex IX
- the extent to which different BGVs need to be developed for different population sub groups and their hierarchy within any tiered framework for application and interpretation
- the extent to which BGVs of different "confidence levels" could be used to support wider industry and public health goals e.g. providing health base for reassurance; demonstrating the integrity of exposure controls; serving as a suitable interim standard prior to the introduction of more developed values, etc.
Scope
It is anticipated the framework will be verified against a representative range of case examples. It is expected that the findings will developed into a peer reviewed publication, following presentation at a suitable scientific conference. Short interim reports on progress are required at 3 to 6-monthly intervals. This project complements an ACC sponsored activity that seeks to explore the basis under which Biological Equivalents (one form of BGV) can be reliably established. It would be expected that the successful research group would liaise with and take account of the findings and outcomes of the ACC supported work.
