Step 6: Scoring and categorising substances on the short list

Scoring substances on the short list

The experts responsible for reviewing and revising the background documents for each substance also proposed both scores for those substances. The proposed scores and categories were then discussed at a two-day expert workshop on scoring the substances, held at ANSES in Paris on 8-9 February 2018.

In order to ensure a systematic approach was taken by all experts and as the lead on task 4.2 on the prioritisation strategy, ANSES proposed a method for scoring each substance against the prioritisation criteria, which is described below. ANSES also provided the experts with extensive links to website and documents relevant to each of the prioritisation criteria to facilitate their work.

The proposed scores and the respective justification were presented and discussed during the workshop held at ANSES in early February 2018. Eleven experts participated in this workshop, representing partners from several work packages across HBM4EU (WP4, WP5, WP8, WP12, WP15 and WP16). At the workshop, participants reached consensus on the scores attributed to each substance.

Substances were scored against three prioritisation criteria under a three-step methodology:

  1. Weighting the established group of prioritisation criteria (hazard properties, exposure characteristics, and public concern) according to their relative importance for prioritising substances in HBM4EU, by means of an adapted Delphi method.
  2. Scoring the substances/group of substances towards each group of criteria.
  3. Calculating a global score for each substance, by summing the products of the weighting score attributed to each individual group of criteria multiplied by the score given to the substance towards the group of criteria of concern.

For further details on this methodology, please consult the report on the stakeholder consultation and mapping of needs.

The question as to whether the prioritisation criteria regulatory status and technical feasibility should and indeed could be systematically scored was considered by work package partners.

With regards to technical feasibility, less-known substances for which analytical biomonitoring method do not yet exist are just as important as substances for which validated analytical methods already exists. Indeed, under HBM4EU research activities are dedicated for the development of analytical methods.

For regulatory status, while the scoring could be oriented towards the perceived need for monitoring an existing regulation and/or the need for risk management at the EU-level, the partners did not have the evidence to support such a judgement. Likewise, proposing a higher score for substances already regulated is not appropriate in the prioritization process, as this would bias towards regulated substances.

The regulatory status of a substance and the technical feasibility of monitoring a substance in human matrices are important aspects that were considered for the substances categorisation and when taking the final decision on which substances to include on the 2nd list of HBM4EU priority substances.

Categorising substances on the short list

The aim of the categorisation exercise was to provide a picture of the state of evidence for each substance and explicitly identify knowledge gaps that might be addressed through human biomonitoring activities under HBM4EU.

Activities to produce knowledge on category B to E substances should serve to increase the level of knowledge on these substances and move them into a higher category, ideally into the Category A.

Category E substances should directly be addressed under Work Package 16, which is focussed on emerging substances.

The categories A to E are described below.

  • Category A: 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 may 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 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 for which HBM data scarcely or don’t exists. Efforts to develop an analytical method to obtain relevant HBM results are needed. Hazardous properties of the substances are suspected, yet greater knowledge on toxicological characteristics and effects on the human health is needed.
  • Category D: 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 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 categorisation of substances was done mainly based on the availability of human biomonitoring data for each substance. The allocation of substances to the categories A to D was based on an expert judgement and was performed by the lead expert responsible for reviewing and revising the background document for each substance.

Substances were allocated to the category that best reflects the information available according to the definition above. The criteria on the substances regulatory status and on the technical feasibility to perform human biomonitoring were also been taken into account.

Regarding the categorisation of groups of substances, the number of substances in the nominated groups of substances of the short list was quite heterogeneous (e.g. the number of lead compounds versus the number of pyrethroids). Where possible, and depending on the number of substances within the group, categorisation was performed for each one of the substances or at least for the identified substances leaders in the group.