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The Chemical Cocktail: new research on mixture effects points to urgent need for action

The developing brain is exposed to a cocktail of chemicals

Throughout our life we are exposed to hundreds of chemicals from multiple sources including from food, consumer products, household dust and drinking water. Current safety assessments mainly focus on single substances. However, combined exposure to many chemicals can lead to unacceptable effects, even if single substances in the mixture are below their individual safety levels.

In 2012 the European Commission’s Communication on `The combination effects – Chemical mixtures` identified several gaps and areas for action. Since then research has increasingly found reason for concern, but this has had little impact on regulatory action.

Last week, on 26th of March “The Chemical Cocktail Challenge” workshop was held in Brussels to discuss recent research from two EU projects EDC-MixRisk and EuroMix, looking at exposure to mixtures of endocrine (hormone) disrupting chemicals (EDC).

EDC-MixRisk project

The EU Horizon 2020 EDC-MixRisk project investigated effects caused by real-life relevant man-made chemical mixtures. It developed a novel approach based on identifying and testing mixtures associated with harmful health outcomes in humans. The project focussed on chemicals affecting the endocrine system. Exposure to such substances is of particular concern in sensitive periods such as the development of the foetus in the womb. It can lead to irreversible changes in the development of organs and tissues and increases susceptibilities to diseases later in life.

By using epidemiology data from a Swedish study of more than 2300 pregnant women, reference chemical mixtures were created to mimic real life exposures (at concentrations found in the pregnant women). These mixtures were tested in various experimental (cell and animal) models, and the toxicological data from these tests were used to establish new methods and strategies for mixture risk assessment.

Most worryingly, the researchers found that even at real life concentrations, EDCs interfere with brain development and growth through impacts on the thyroid hormones  which are essential for brain development.

Professor Barbara Demeneix, who was part of the research team,  said:

´Thyroid hormone signalling and numerous thyroid hormone dependent genes were disrupted by the mixture in the different models tested. The findings reveal a mechanism whereby brain development is affected by exposure to the chemicals at relevant human exposure levels.´

The overarching conclusion from the EDC-MixRisk project is that current regulation of man-made chemicals systematically underestimates the health risks associated with combined exposures to EDCs or potential EDCs. More details can be found in the EDC-MixRisk policy briefing.

EuroMix project

The EuroMix research aimed to establish new testing and assessment strategies for chemical mixtures in order to develop better mixture risk assessment methodologies.

The project identified different methods and delivered a test strategy to generate missing hazard data. The results of EuroMix contribute to a practical implementation of mixture risk assessment. Policymakers and researchers are invited to use the new approaches. The main deliverables of the EuroMix project are published online.

CHEM Trust’s view

Ninja Reineke, Head of Science at CHEM Trust, gave a presentation at the conference and pointed to the urgent need to include mixture assessments in EU laws given that children are already exposed to many known harmful chemicals today, including those capable of disrupting children`s brain development.

Dr Ninja Reineke said:

´The results from these two research projects should act as a wake-up call for EU policymakers as their findings show that chemical mixtures can impact human health at current exposure levels. Action is needed now to protect us from such mixtures of hazardous chemicals.’

For more information