New project aims to estimate scientific basis of health risks posed by substance mixtures

The BfR is involved with two work groups in the project, which is being coordinated by the Dutch National Institute for Public Health and the Environment (RIVM).

In addition to residues of the active substances contained in plant protection products, the work focuses on contaminants in foods and potentially health-damaging food ingredients. "The goal is to be able to make a more realistic estimation on a scientific basis of the health risks posed by substance mixtures of this kind," explains BfR President, Professor Dr. Dr. Andreas Hensel. Strategies for identifying toxicologically relevant substances, for example, and the first results of tests on the toxicity of multiple residues of the active substances contained in plant protection products are to be presented at the 8th Consortium Meeting.

Consumers are exposed every day to a wide variety of undesired substances which are potentially damaging to health. Using computer-supported in silico methods (QSAR) and with the help of exposure modeling, a strategy for prioritizing the substances relevant to risk assessment in mixture experiments has been developed in the EuroMix project. This enables the fast and necessary restriction of the extensive list of substances and substance classes to be tested. As a large number of different substance mixtures is conceivable, EuroMix has concentrated on a small number of particularly relevant key mixtures identified at the beginning of the project. One area of main focus here lies in mixtures of the active substances contained in plant protection products.

Parallel to this, a test strategy was devised to test and characterize the effects of substance mixtures of many different classes with regard to their damaging effect on the liver, the development of the organism and the endocrine system. New methods were developed here among other things which enable a high test throughput at low costs as an alternative to experiments with animals in order to facilitate the testing of a large number of relevant substance combinations.

To test combination effects in the liver, for instance, a toolbox was specially developed for the specific symptoms of pathological fatty liver (steatosis) which permits a forecast of combination effects with the help of consecutive in vitro test methods. The successful use (proof of principle) of the system has already been published and was achieved with a pesticide with a known mechanism of action. This toolbox was then used for the characterization of mixture effects. It could be seen here, especially for the class of pesticides, that above all dose addition effects predominate for which a risk assessment concept already exists. The successfully tested toolbox can also be used for the testing of other relevant substance classes in order to characterise and/or examine substance combinations for effects such as inhibition, dose addition or synergism. The objective here is to be able to better assess the interaction of substances in mixtures. At the end, a web-based evaluation toolbox should be available for the analysis and overall assessment of mixtures.

Source: https://www.bfr.bund.de/en/press_information/2018/35/are_substance_mixtures_in_foods_more_dangerous_than_individual_substances_-206633.html