Imperial College London, London W12 0NN, UK
25 October 2018
The EuroMix consortium organised the third of a series of workshops to discuss international harmonisation of approaches to the risk assessment of combined exposure to chemicals on 25 October 2018. The workshop was held at the Hammersmith Campus, Imperial College London, London W12 0NN, UK. The 15 participants at the workshop were drawn from a range of geographical and regulatory areas, with risk assessors from several regions (Europe, USA, Canada and Brazil) and authorities (EFSA, JRC, OECD, WHO, US EPA, RIVM, BfR) present.
The main aims of this workshop were to explore ways in which
the EuroMix toolbox can contribute to harmonised scientific approaches to the
risk assessment of combined exposures to chemicals in the diet, in relevant
legislation. In support of this objective, illustrative case studies from the
USA and from Europe were presented and discussed, and used to inform guidance
for consideration at the final workshop.
The programme and presentations can be accessed here.
In general, there is appreciable alignment of the principles
for assessment of combined exposure to multiple chemicals by OECD, EFSA, EPA
and other organisations. These all emphasise the importance of problem
formulation, including specification of the objectives and acceptable degree of
uncertainty for assessment, the basis for grouping chemicals and the choice of
assessment approach. There is also general agreement on the need for tiered
approaches for both hazard and exposure assessment, to avoid being overly
conservative. The use of mode of action information in refining assessment
groups has also been broadly incorporated, as has been transparent delineation
of uncertainties at each tier. In a number of chemical sectors, there is common
application of these principles. However, in the area of pesticides, there are
significant differences between the proposed approach in Europe and that which
is in use in the USA.
The EuroMix toolbox has potential application, regardless of
the approach used, in different sectors or geographical regions, for both data
rich and data poor chemicals. Whilst harmonisation of the specific risk
assessment methodology might not be possible, at least in the short term, the
EuroMix toolbox can contribute to harmonisation of the principles used, in
addressing the above issues, the standard of reporting and data templates.
EuroMix is developing a Handbook to provide best practice for the range of
problem formulations that might concern risk managers and will encourage
further harmonisation, to the extent possible.
The conclusions of the workshop have been written
up in the report of the meeting and will be explored further at the 4th
workshop in the series, to be held in Geneva, 15th April 2019.