Arbejdsrapport fra Miljøstyrelsen, 10/2004 – Substitution af overflade aktive stoffer i kosmetiske produkter

Substitution of Surfactants in Cosmetic Products

Summary and conclusions

In this project, the environmental properties of a range of substances that are used in cosmetic products have been thoroughly investigated, partly by literature reviews and partly by laboratory tests. Within the selection of raw materials used by the enterprises producing cosmetic products, the majority of the chemical substances can be characterised as having a low potential for environmentally hazardous effects. Only a minor part of the chemical substances can be characterised as being environmentally hazardous. During the project period, several of the most environmentally problematic substances were phased out, or are in the process of being phased out by substitution with less hazardous substances. For a range of substances, it has not been possible to obtain environmental data in literature or in material safety data sheets. In those cases in which these substances were considered of great importance for the enterprises, the environmental properties in relation to anaerobic biodegradability and chronic effects were investigated in laboratory tests.

In summary, the following results have i.a. been obtained:

As a result of the generation of new data, it is expected that a range of raw materials will gain broader use or will be used in new products. The tests performed contributed to achieving compliance with the Eco-label criteria for some of the substances.
Preservatives were included in the project, as it is generally difficult to find preservatives that are not hazardous to the environment. Furthermore, suitable substitutes for parabenes, which are known to have potential endocrine disrupting effects, were searched. Possible substitutes for environmentally hazardous preservatives and alternatives to parabenes are suggested in the review of preservatives.
Some of the enterprises participating in the project have made a shift from products based on mineral oil to products based on vegetable oil for dissolution of dirt. With respect to human health, vegetable oils are preferred to mineral oils, as vegetable oils may dissolve dirt and at the same time keep the skin barrier intact by leaving a fatty emulsion on the skin. So far, the problem with several of the vegetable oils used has been the lack of data on the anaerobic biodegradability. In addition, several of the vegetable oils are considered potentially bioaccumulable due to high log K_ow values. During the investigations performed, it was demonstrated that several of the substances are anaerobically biodegradable, and that the substances have a low toxicity in long term-tests in spite of their high log K_ow value.
Data on anaerobic biodegradability were generated for 24 substances, which are used in cosmetic products. The majority of the substances are biodegradable under anaerobic conditions. The enterprises can use these data, e.g. when applying for a licence to use the Eco-label.
When investigating their anaerobic biodegradability, some of the substances proved toxic in the test. Substances with a high inherent toxicity will inhibit the anaerobic bacteria and thus the degradation. Therefore, the result of such a test will show a lack of biodegradability, which may simply be a toxic effect caused by the concentration of the test substance used in the degradation test. During the project, experiments with a modification of the standardised guideline (ISO 11734) were thus initiated, and promising results were obtained.
In hair conditioners and hair products, cationic tensides are used to decrease static electricity and to ease the combing of the hair. Certain of the cationic tensides used turned out to be environmentally hazardous, due to a.o. high aquatic toxicity and sparse documentation of biodegradability. Functionally applicable and less environmentally hazardous alternatives were found through the screening of environmental hazard and the investigations carried out in the laboratory.
Generally, it is expected that substances with a high log K_ow value (≥ 3) will bioaccumulate in e.g. aquatic organisms. Due to the bioaccumulating properties, it is expected that these substances will show a higher toxicity in long-term tests compared to short-term tests. Readily biodegradable detergents are often metabolised in the organism, and the environmental risk of exposure to detergents with a log K_ow value ≥ 3 is, thus, uncertain. Information on the bioaccumulating properties of detergents or their effects in long-term tests is generally sparse. A range of suitable raw materials (with log K_ow values ≥3) and possible candidates for product development were therefore chosen for investigation of short-term and long-term effects, respectively. The results achieved indicate that a high log K_ow value (≥ 3) does not increase the toxicity of the substance in long-term tests, provided that the substance is readily biodegradable.
The result of the investigations of the relation between bioaccumulation and long-term effects showed a.o. that, in spite of its high log K_ow value, the cationic tenside Behenyl PG-Trimonium Chloride, is recommended as a substitute for Cetrimonium Chloride. Based on these results, one of the enterprises has applied for an Eco-label licence for products in which Behenyl PG-Trimonium Chloride is substituted for Cetrimonium Chloride.