Verfolgung von Umweltbelastungen durch Moschusverbindungen in repräsentativen Umweltproben - Teil II
Wenzel, Andrea; Lepper, Peter
Schmallenberg, Fraunhofer Institute for Molecular Biology and Applied Ecology
Part II: Bewertung der Analysen von Nitro- und polycyclischen Moschusverbindungen in Umweltproben
Results of the retrospective analyses of synthetic musk fragrances in aquatic biota
Polycyclic musks and nitro musks belong to the most important synthetic fragrances and are used in a variety of perfumes, soaps, detergents and cosmetics. These synthetic compounds don not have structural similarities with the natural musks that are extracted from exocrine gland secretions of musk ox and musk deer.
Samples of marine (bladder wrack, blue mussel, eel pout, seagull egg) and limnic biota (zebra mussel, bream) showed only low levels of nitro musks with a downward trend. In contrast, polycyclic musks were detected in occasionally extreme high concentrations. Galaxolide® (HHCB) and Tonalide® (AHTN) were the dominant polycyclic musk compounds. These findings comply with the reported actual worldwide annual production which is dominated by polycyclic musks (85 %). Nitro musks’ share in the worldwide annual production is only 12 %. In Germany, musk xylene has not been used in new products since 1994 due to a voluntary ban by the German Industrieverband Körperpflege und Waschmittel (IKW).
The synthetic musks enter the aquatic environment mainly via sewage effluents. As a result, there is a decrease in the fragrance levels within the organisms from the limnic to the marine environment.
Blue mussels from the Wadden Sea of Lower Saxony exhibited varying levels between 0.5 and 1.7 μg/kg wwt HHCB and 0.4-2.5 μg/kg wwt AHTN in the observation period 1998-2000. Overall, the concentrations of nitro musks were found to be lower than the levels of the polycyclic compounds in all samples and were generally under the limit of determination (LOD) of 0.1 μg/kg wwt since 1996. Blue mussels from the German eastern seaboard were only slightly contaminated with synthetic musk fragrances. The levels found were either slightly above or below the LOD during the period from 1992 to 2000.
Based on the investigation of bream fillets of the latest year of the observation period (2003), the following hierarchy in terms of exposure to synthetic musks of limnic biota at the different sampling sites could be established:
Belauer See << Mulde < Donau < Elbe < Rhein < Saale < < Saar.
On German territory, fish from the Elbe river exhibited in 2003 levels of 10-75 μg/kg wwt of HHCB and 0.84-8.7 μg/kg fw of AHTN. During previous years, the exposure of breams had been higher at some sampling points with exception of the sampling location Blankenese. At this location the HHCB-burden appears to stay constant after a considerable drop from higher concentrations in previous years occurred in 1998 whereas in the upper reaches of the river at the sampling location Prossen the HHCB-concentration appears to rise with time. At the other sampling locations along the river the HHCB-burden is declining with time. The AHTN concentrations exhibit a more uniform pattern. They are steadily falling off at all sampling points along the Elbe. In the Elbe tributaries Saale and Mulde the HHCB- and AHTN burdens appear as well to decrease with time. However, since 2000 the HHCB level is rather staying constant than to decrease any further.
The levels of synthetic musks in breams from the river Rhine are highest at the sampling site Iffezheim. Upstream as well as downstream from this location the levels in bream fillet are decreasing. However, concentration levels and time-dependent changes are different at different sampling sites. Whereas the AHTN-levels are falling off steadily at all sites the HHCB-concentrations in samples of the sites Weil, Koblenz and Bimmen appear to stay constant since 1999 after occurrence of a considerable drop compared to concentrations prevailing in the years before 1999. At the site Iffezheim the HHCB-levels are rising again since 2000. Concentrations of HHCB in bream fillet were found to lie within 29 and 419 μg/kg wwt and the concentrations of AHTN within 3,2 and 65,3 μg/kg wwt during the observation period 1995-2003.
With regard to the river Donau only results for 2002 and 2003 are available, With respect to the HHCB and AHTN burdens of bream fillet the situation in the Donau is comparable with the situation of the Rhine at the sampling sites Koblenz and Bimmen in the same years. Wet weight related values are in the range of 38 to 78 μg/kg HHCB and 3-5 μg/kg AHTN. The level of pollution with synthetic musks is not very different at the three sampling sites along the Donau.
The exposure of fish to synthetic musks is by far highest in the Saar. In the observation period from 1994 to 2003, concentrations of 366 to 2005 μg HHCB/kg wwt and 22 to 605 μg AHTN/kg wwt were found. Furthermore, less abundant fragrances (ADBI, AHDI and ATII) had as well accumulated in the breams of the Saar (concentrations up to 50 μg/kg wwt were found). This is in clear contrast to all the other sampling sites. There, only traces of these substances were detected. During the monitoring period the exposure to HHCB in relation to AHTN increased markedly in all analysed fish samples.
With respect to the ecotoxicological relevance of the determined concentrations of synthetic musks in fish, it appears impossible to reach clear-cut conclusions. Long-term exposure investigations need yet to be conducted. Furthermore, tissue concentrations are generally not recorded in the course of ecotoxicological tests. However, careful extrapolation by means of published BCFs indicates that the levels of exposure for fish in hot spot regions (foremost fish from the Saar) may exceed the predicted no effect concentrations (PNEC) for HHCB and AHTN.