Endocrine Disruption Assessment of UVCBs (substances of unknown or variable composition, complex reaction products or biological materials): A case study using grease thickeners
Abstract: New hazard classes for endocrine disruption (ED) have been introduced under Classification and Labelling (CLP) regulations. Mixture rules are expected to be applied to UVCBs (substances of unknown or variable composition, complex reaction products or biological materials), so that ED classification is based on the most conservative outcome for the whole substance and relevant constituents present above a concentration limit (e.g. 0.1%).
An approach for ED assessment of UVCBs has been developed for petroleum substances: gather available data (on whole substance, substance composition and individual constituents), consider whether classification is possible based on existing classifications for individual constituents or whole substance data, and finally evaluate data for individual constituents. This general ED assessment approach for UVCBs has been adapted for use in the initial prioritisation of grease thickeners.
Most grease thickeners are either registered at lower tonnage levels, or using read across from similar substances, so ED assessment based on whole substance data is not possible as no or limited relevant whole substance data are available for human health or the environment. Therefore, the prioritisation for ED assessments has focussed on relevant constituents.
Compounds relevant for the ED assessment were identified, including the substances themselves and the constituents and impurities therein, immediate transformation products and read across source substances. This expanded the initial list of 50 substances in the grease thickener portfolio to 191 compounds requiring ED evaluation. Substance characterisation is ongoing for some complex substances, which could expand the list further.
No constituents have yet been concluded for ED and most have limited relevant data. Grease thickener substances consist primarily of metal salts of carboxylic acids, with differences in chain lengths, functional groups and metal cations, as well as substances with more complex structures. Therefore, the reliability assessment and interpretation of data is likely to be complex, especially as some substances are poorly soluble and metal salts are outside the applicability domain of many in silico models.
This case study demonstrates some of the challenges associated with ED assessments for these substances and offers perspectives and strategies for dealing with ED assessments of complex substances.
Disclaimer/ Disclosure (optional): The authors would like to thank the European REACH Grease Thickeners Consortium (ERGTC) for sharing this work.
Author(s):
Rhiannon Smith wca Environment Ltd. United Kingdom
Rebecca Brown wca Environment Ltd United Kingdom This Author Is the Presenter
Maria Blanco-Rubio Shell Global Solutions Netherlands
David Saunders Shell Global Solutions Netherlands
Olivia Tran wca Environment Ltd United Kingdom
Lucy Kennelly wca Environment Ltd United Kingdom
Kate Roylance wca Environment Ltd United Kingdom
Owen Green wca Environment Ltd United Kingdom
Endocrine Disruption Assessment of UVCBs (substances of unknown or variable composition, complex reaction products or biological materials): A case study using grease thickeners
Category
Poster Presentation