Our food, our water and the things we use every day are constantly contaminated by hundreds of harmful chemicals that build up in bodies and the environment.
Until about a decade ago, safety watchdogs only rated toxicity levels for each separate chemical on its own. They thought the effect of a build-up of many different chemicals at once was safe if each chemical in the mixture was within its own legal exposure limit.
Toxicologists at Brunel University London showed for the first time that even if each chemical in a mixture is at a safe level, the overall cocktail effect of the mixture is dangerous. But for years, chemical safety legislation stayed the same.
Mixtures of plasticiser chemicals (phthalates) found in everyday things like food wrappers, pesticides, toys, cleaning products and cosmetics are linked to male infertility. The finding helped trigger major moves in Europe-wide safety policy.
Pesticides, biocides, food contaminants and industrial chemicals are the most common types of harmful chemical mixtures people are exposed to in everyday life.
The 2020 EU Chemical Strategy for Sustainability pledged to fast-track risk assessments for pesticides and bring in new protective regulations for other chemical mixtures. This will protect 445 million Europeans from mixture risks. The European Chemicals Agency in 2017 used Brunel’s research to back restrictions on a group of four phthalates used in household goods, to protect 400,000 boys at risk from exposures.
In the last 10 years, the Brunel team, led by Dr Andreas Kortenkamp, published more than 30 scientific studies into the toxic effects of chemical mixtures. The resulting raft of evidence strongly suggests toxicologists can predict the effects of multi-chemical cocktails when they know how toxic each chemical in the mix is. In many different experiments with fish, rodents and cultured cells, the team accurately predicted mixture effects. Working with the European Food Safety Authority, the Brunel team put together a new workable way to group chemicals for mixtures risk assessment. The new approach brought in by the authority will influence maximum residue levels for toxic pesticides in food in Europe. It means people will be better protected against the extra risks of harm caused by a mix of pesticide residues found in most foods.
Key findings from this body of Brunel research are that a mixture of chemicals is usually more toxic than the most toxic chemical in the mix, and that mixtures of chemicals can still be dangerously toxic even if each chemical in it is at safe levels. Altogether, the toxicology team’s research shows that ignoring the effect of mixtures of chemicals underestimates the risk of toxicity.
Professor Andreas Kortenkamp - Traditional chemicals risk assessment has a quite artificial orientation: It treats chemicals as if they act in isolation, when in reality there is exposure to multiple substances. For more than 15 years, our team have been engaged in efforts to find ways of improving risk assessment by taking “cocktail effects” into account. This work has proceeded in stages: Firstly, when we have information about the toxicity of individual mixture components, is it possible to predict the effects of the combination? Working with mixtures of endocrine disrupting chemicals we have shown that this is achievable. Secondly, what is the composition of mixtures of environmental relevance, and what effects do they produce? Work on this aspect of the mixtures issue is currently proceeding in our group. We are also interested in making an impact on chemical regulation by addressing the questions: Which chemicals should be grouped together for mixtures risk assessment? What are scientifically sound grouping criteria? We have prepared scientific reports for the European Commission, including the State of the Art Report on Mixture Toxicology. Currently we are writing a State of the Art Assessment for Endocrine Disrupters, a project also commissioned by the European Commission. Another research interest is in unravelling the details of estrogen signalling and estrogen-mediated effects with a view to understanding hormonal cancers, especially breast cancer. Here, I closely collaborate with Dr Elisabete Silva. Qualifications1983: Degree in Chemistry, Philosophy and Educational Sciences from University of Muenster, Germany 1989: PhD (with distinction) from Bremen University, Bremen, Germany Career 1990-1991: Post-doctoral Fellow at Queen Mary London, University of London. 1991-2000: Lecturer in Environmental Toxicology, School of Pharmacy, University of London, London. 2000-2005: Senior Lecturer, School of Pharmacy, University of London, London. 2005-2007: Reader and Head of Centre for Toxicology, School of Pharmacy, University of London, London. 2007-2011: Professor for Molecular Toxicology, Head of Centre for Toxicology, School of Pharmacy, University of London, London. 2011-present: Professor in the Institute for the Environment, Brunel University.