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Combination effects of chemicals

Throughout our lives we are exposed to a variety of chemicals, contained in food, water, medicines, the air we breathe, cosmetics and health care products, shoes, clothing and other consumer products. In the natural environment, living organisms are also exposed to a complex cocktail of chemical substances.

Current regulatory approaches to the assessment of chemicals are usually based on the evaluation of single substances, chemical by chemical. The assessments include safety margins to take account of uncertainties, such as how exposure to many different chemicals  may affect humans and the environment.  However, there are concerns that this does not provide sufficient security and that the combination effects of chemicals should be addressed in a more systematic way. 

Acknowledging these concerns, the Council of Environment Ministers adopted conclusions on the combination effects of chemicals on 22 December 2009. In its conclusions, Council invited the Commission to assess how and whether existing legislation addresses this problem and to suggest appropriate modifications and guidelines. Read more...

On 31 May 2012 the Commission reported to the Council in its Communication from the Commission on Combination effects of Chemicals (Chemical mixtures).

In this report, the Commission engaged to launch a new process to ensure that risks associated with chemical mixtures are properly understood and assessed. The report states that EU laws set strict limits for the amounts of particular chemicals allowed in food, water, air and manufactured products, but that the potentially toxic effects of these chemicals in combination are rarely examined. Under the new approach, the Commission will identify priority mixtures to be assessed and ensure that the different strands of EU legislation deliver consistent risk assessments for such priority mixtures. The Commission will also tackle some of the data and knowledge gaps to improve understanding of the mixtures to which people and the environment are exposed.

The new Commission approach draws heavily on the recent opinion of the three non-food scientific Committees: "Toxicity and Assessment of Chemical Mixtures" as well as on the "State of the Art Report on Mixture Toxicity".

The number of chemical combinations is potentially enormous and it is neither realistic nor useful to test every possible combination. Methodologies for assessing/estimating the combination effects of chemicals are being developed and used by scientists and regulators in specific circumstances but as yet there is no systematic, comprehensive and integrated approach. In 2007, DG Environment contracted a study to review the current scientific knowledge and regulatory approaches. The study entitled "State of the Art Report on Mixture Toxicity" was completed in 2009 and has provided input to the Commission work on the recommendations requested by the December Environment Council (see above).

The state-of-the-art report comprises the following five sections:

  • Executive summary
  • Part 1 – The state of the art of mixture toxicology – a critical appraisal of published scientific literature
  • Part 2 – Identification and description of current provisions fro taking into account hazards and risks arising from mixture toxicity in 21 pieces of EU legislation
  • Part 3 – Survey on approaches and practical experiences in assessing the mixture toxicity of complex environmental samples and waste samples in EU Member States
  • Part 4 – Overview of approaches to hazard and risk assessment of chemicals mixtures in the USA, Japan and international bodies

The Commission has provided opportunities for discussion and commenting on the report to the relevant authorities in the Member States and to representatives of the interest groups principally concerned.

Other organisations or individuals with interest and relevant experience were able to comment until 30 April 2010. Their comments are published here. (This document reflects the opinion of the contributors and does not necessarily constitute the views of the European Commission.)

A workshop on the State of the Art Report on Mixture Toxicity was held on 21-22 June 2010, Brussels: Agenda - Summary - Presentations