Risk Assessments-executive summary
Substance Group: Polycyclic Musk AHTN

The polycyclic musks AHTN and HHCB are used as fragrance ingredients in consumer products like cosmetics and detergents and cleaning agents. They are important ingredients in fragrances because of their typical musky scent and their fixative properties.

Over the last decade synthetic musks have attracted the attention of environmental researchers due to their presence in environmental samples and human mother’s milk. As a reaction various risk assessments were carried out showing the risks were generally of low concern.

In the past decade the use volume of these substances in detergents and cleaning agents is declining, from circa 3300 tons in 1992 to 1800 tons in 2000. In household cleaning products, complex perfume-mixtures containing polycyclic musks are often purchased as such from the fragrance compounders and are used in the different formulations. Therefore, HERA was not able to come to representative volume data on use by the formulator companies.

The current risk assessment is made along the lines set out by the HERA methodology. The standard level risk assessment triggered a higher-tier approach to refine the risk assessment for the soil and sediment compartments. Using the more realistic monitoring data instead of the modelling approach, the environmental risk assessment for AHTN and HHCB shows that (1) sufficient data are available to assess the environmental risks; (2) the assessment can be based on measured concentrations in the northern region of the EU; (3) risk ratios are generally below 1; (4) however, for sediment organisms living in areas contaminated with a high effluent load, the risk ratios may be above 1. However, it should be remarked that the uncertainty around the toxicity to sediment organisms is high which is incorporated as an additional factor in the risk ratios.

Monitoring data are available for the northern region of the EU, but it is not known whether they are also representative for the southern European countries. An analysis was made of the regional variation of the use of AHTN and HHCB and of the trends in time. For this risk assessment, as a worst case, it was assumed, as a ‘worst case’, that the consumer use in southern European areas was 5 to 7 times above the use in northern Europe. The Berlin area was recognised as an area where sediment organisms may be at risk due to the combination of high loaded effluents and an extremely low dilution factor. The report includes an analysis of the uncertainties in the risk characterisation. As a follow-up, a large-scale programme was launched recently to sample sewage treatment plants and sediment in a number of southern European countries and in Berlin. Moreover, toxicity studies with sediment organisms are carried out to refine the risk assessments for these organisms.

A human risk assessment document was also developed within the scope of the HERA project. The preparation of these HERA risk assessments ran in parallel to the risk assessments for AHTN and HHCB in the context of the EU Existing Chemicals Programme.