Categorisation of substances in HBM4EU according to existing knowledge of internal exposure

The aim of HBM4EU is first to get information on the human internal exposure of (potentially) toxic substances and substance groups in the EU population(s), and secondly, to be able to interpret the internal exposure (biomonitoring) information in terms of health consequences in relation to sources and pathways of (aggregated) exposure. To enhance transparency for selection of chemical substances to be included in HBM4EU research activities, substances will be categorised. Criteria for categorisation will be mainly based on the availability of human biomonitoring data for each substance, its regulatory status, hazard information and the availability of analytical methods for biomarker analysis.

The aim is to be fully transparent about knowledge gaps that might be addressed through human biomonitoring activities under HBM4EU. Substances will pass from Category E over D, C, B towards Category A as more information becomes available. Fully characterised substances should end up as category A substances. Activities related to the categories B to E substances which are integrated in the HBM4EU work plans should serve to increase the level of knowledge on these substances and move them into a higher category, ideally into the Category A.

The allocation of substances to the categories A to D is based on an expert judgement using the information in the background documents. Category E substances should directly be addressed under WP16 dedicated to the emerging substances.

The categorisation supports the prioritisation process and indicates the information gaps hence allowing to develop targeted activities in HBM4EU to fill the knowledge gaps. Categorisation provides a first idea on the total knowledge for each substance from the perspective of human biomonitoring, related to possible health consequences.

Categorisation of substances

The categories A to E are described below:

• Category A substances are substances for which HBM data are sufficient to provide an overall picture of exposure levels across Europe, and interpretation of biomonitoring results in terms of health risks is possible. Risk management measures have been implemented at national or European level. Improvement of knowledge for these substances will therefore focus on policy-related research questions and evaluation of the effectiveness of existing regulatory measures.

• Category B substances are substances for which HBM data exists, but not sufficiently to have a clear picture across Europe. Also, knowledge on the extend of exposure, levels and impact on the human health should be improved, in order to give policy makers relevant and strategic data to establish appropriate regulations and improve chemical risk management. Analytical method and capacities to monitor the substances across Europe might have to be improved.

• Category C substances are substances for which HBM data scarcely or doesn’t exists. Efforts to develop an analytical method to obtain relevant HBM results need to be done Hazardous properties of the substances are identified, yet greater knowledge on toxicological characteristics and effects on the human health is needed. Interpretation of HBM data is not possible, due to the lack of HBM guidance values.

• Category D substances are substances for which a toxicological concern exists but HBM data are not available. HBM4EU research may be focused on the development of suspect screening approaches permitting to generate a first level of data enabling to document the reality of human exposure and better justify further investment in a full quantitative and validated method development.

• Category E substances are substances not yet identified as of toxicological concern and for which no HBM data are available. A bottom-up strategy will be applied, consisting to non-targeted screening approaches coupled to identification of unknowns capabilities for revealing, and further identifying, new (i.e. not yet known) markers of exposure related to chemicals of concern for HBM (parent compound or metabolite).

The category for each single substance is documented in the background document. Substance groups are expected to include a range of substances, distributed across categories.

The categorisation supports the prioritisation process and indicates the information gaps hence allowing to develop targeted activities in HBM4EY to fill the knowledge gaps. Categorisation provides a first idea on the total knowledge for each substance from the perspective of human biomonitoring, related to possible health consequences.