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March 28, 2014

ECHA Report Includes Recommendations for Exposure Assessment and Risk Characterization of Nanomaterials under REACH

Lynn L. Bergeson

On March 26, 2014, SAFENANO announced that the European Chemicals Agency (ECHA) published a report entitled Human health and environmental exposure assessment and risk characterisation of nanomaterials: Best practice for REACH registrants. The report summarizes the outcomes of the third (and last) meeting of the Group Assessing Already Registered Nanomaterials (GAARN). The September 30, 2013, meeting focused on discussing the approach and challenges faced by participant registrants when documenting the human health and environmental exposure assessment and risk characterization of their substances while registering them under the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation. The report states that the outcomes of the discussion “can be viewed as generic recommendations for the exposure assessment and risk characterisation of NMs under REACH, while considering the present scientific knowledge on the field of nanotoxicology and practice, as well as challenges from participating registrants.” The report states that the provisions that apply to the registration of nanomaterials are the same as those for any other chemical substance, but notes that, “in line with scientific developments, there are specific considerations that registrants should report in specific endpoint sections, as this information will facilitate the evaluation of the adequacy of the tests performed and data obtained with regard to the safety assessment of NMs.” According to the report, the registration dossier should contain a comprehensive physicochemical characterization of the registered nanoform(s).  Only when well-characterized nanoforms are reported in the dossier, can a read-across approach or use of existing data be considered for the purpose of hazard assessment.  Registration dossiers including nanomaterials and bulk substances under the same technical dossier should include specific exposure scenarios for nanomaterials if these differ from the exposure scenarios developed for the bulk materials.  The report states that, “[i]n principle, the existing risk assessment paradigm developed for traditional chemicals” should also apply to nanomaterials.  According to the report, comprehensive risk assessments for nanomaterials currently present challenges both for human health and the environment.  The following conclusions can be drawn:

Regarding the risk assessment for workers, due to the lack of validated modelling tools for nanomaterial exposure, field measurement data are currently preferred to support the risk assessment.  If possible, the risk assessment should follow a multi-metric approach.  The use of qualitative approaches is allowed to support measured or estimated exposure data.  Concerning RMMs, the conventional control technologies to handle dusty materials are applicable to NMs and provide good control if implemented and maintained correctly.

With regards to the environment, the lack of specific hazard data complicates the risk assessment. Moreover, there are significant limitations in the applicability of conventional exposure assessment models. Registrants are advised to collect information on environmental release when possible (RIPoN 3).  The current report proposes best practice to achieve realistic exposure data that can be used in environmental risk assessments.

In general, it is important to conclude with the reminder of the legal obligation that registration dossiers need to be updated with new nano-specific studies as scientific developments are progressing.  Safe use claims under REACH should be based on explicit and transparent documentation supporting the hazard, exposure and risk assessment of NMs.  Registrants are reminded that a lack of (hazard) data does not automatically mean that there is a lack of specific hazards or risks for a substance.