Research on toxic substances in consumer goods, cosmetic products and tobacco

Nowadays, toxicological tests are mostly carried out with individual substances. However, consumers usually do not come into contact with individual substances, but with complex substance mixtures: when consuming food, through the migration of components from food packaging into the food, and when using personal care products and other products such as toys or clothing. In addition, the manufacturing process and use of consumer goods can lead to the formation of secondary products whose structure and toxicity are largely unknown, although substance interactions are also a possibility. This means that it is necessary to test substance mixtures that can migrate from consumer products (such as food packaging) into food or directly into the human body for their harmlessness to health.

The aim of the study of substance mixtures from consumer goods is to identify substances that can migrate and are problematic, such as plasticisers, vulcanisation accelerators (mercaptobenzthiazole, thiurams) or azo dyes. For example, azo dyes are used in toys, clothing and cosmetic products as colourants and in hair dyes. Some azo dyes are known to be carcinogenic and allergenic, but the available toxicological data is incomplete.

In order to develop further criteria for the risk assessment of the corresponding consumer products and to be able to identify options for action in the case of products with ingredients that are harmful to health, the toxicological properties of the substances capable of migration and their metabolic products are to be recorded and their skin penetration determined.

Areas of research

• Transfer of plasticisers into food
• The sealing compounds used in the closures (twist-off lids) of glass containers for food contain high proportions of plasticisers, mainly phthalates, which can migrate to a significant extent into fatty foods. Edible oils can also be contaminated with these substances as a result of the transfer of plasticisers from the materials used in the extraction and processing (e.g. hoses or containers). Only a very limited amount of data is available to estimateClose dialogestimateEstimateTo glossary exposureClose dialogexposureExposureTo glossary to plasticisers from these sources.
• Perfluorochemicals in food packaging
• The possible transfer of perfluorochemicals, as well as of fluorotelomer alcohols (FTOH), must be considered as one of the causes of the concentrations of perfluorooctanoic acid (PFOA) found in human blood. These substances are used to make paper water and grease repellent for food contact. There are indications that perfluoroalkyl acids are formed from FTOH in the human body. PFOA has a very long half-life in the human body. To date, only a limited amount of data on the migration of PFOA and FTOH is available to assess this exposure pathway.

Various health-related effects of substance mixtures can now be investigated in suitable cell cultures. One advantage of testing in cell cultures is the possibility of testing a large number of substance mixtures on the basis of different toxicological parameters. Analytically characterised migrates and defined components of migrates are to be examined in cell cultures for their cell-damaging, skin-irritating and sensitising effects, but also with regard to their possible mutagenic effect. In addition, skin penetration of selected migrates is determined in an in vitro model.

Research fields

• Toxicological studies on substances from consumer goods
• The genotoxicity of azo dyes and their metabolites as well as vulcanisation accelerators is to be determined in a bacterial mutagenicity test (Ames test) and an in vitro test on mammalian cells (V79 micronucleus test). In addition, experiments are to be carried out with eluates from dyed textiles and migrates from rubber materials.
• The genotoxicity of the model dye Direct Blue 14 and its metabolite o-tolidine were investigated in a bacterial mutagenicity test (Ames test) and in an in vitro test on mammalian cells (V79 micronucleus test). In addition, initial experiments were carried out with eluates from dyed textiles.
• Metabolism of azo dyes
• The aim of in vitro experiments with skin bacteria is to clarify the extent to which microbially produced metabolites of azo dyes contribute to the systemic availability of aromatic amines.
• Results:
• Azo cleavage to carcinogenic amines was detected for three cosmetic dyes. The safety of these substances must be questioned.
• For an allergenic textile dye (disperse yellow 3), a method for the quantification of azo cleavage was established and validated. Azo cleavage was also demonstrated.

In further studies in collaboration with the Charité University Hospital in Berlin, the sensitising potential of the azo dye and its metabolites is being investigated. Parallel studies are addressing the issue of skin penetration.

• Development of a screening system for the toxicity of migrants from consumer goods in keratinocytes
• For the risk assessment of ingredients of cosmetic products and of consumer goods that come into contact with the body, information on skin penetration is needed in addition to data on the toxicity of the substances in order to determine the systemic exposure. For this purpose, a method for determining skin penetration in human skin cells in vitro is to be established based on the OECD Guideline 428. Pesticides, azo dyes in textiles and vulcanisation accelerators in rubber materials are used as model substances.

Results:

• For cell culture systems from primary cells and cell lines, a special method was developed that enables simultaneous detection of cell growth and programmed cell death (TUNEL-Ki67 double labelling) and thus complements established methods for cytotoxicity measurement (MTT, neutral red test). Binary mixtures of model substances showed additive to over-additive effects in cytotoxicity and apoptosis with a simultaneous reduction in proliferation.
• Studies on harmful substances in water pipe smoke
• Around 100 million people worldwide smoke water pipe daily. This form of tobacco consumption is now also on the increase in Germany. Initial studies show that the smoke of the water pipe contains high levels of carbon monoxide and metals as well as metal oxides. Traces of polycyclic hydrocarbons have also been detected. An initial study at the BfRshort forGerman Federal Institute for Risk Assessment is intended to provide information on the exposure of a water pipe smoker to this class of substances.