Objectives: Musk xylene (MX), an environmentally important nitromusk compound, is used in different fragrances and soaps as substitute for natural musk. MX is known to occur in breast milk and plasma samples from the general population. Biological monitoring was carried out to study the change in MX concentrations in plasma from the general population over a period of about 6 years.
Methods: Forty-one human plasma samples from the general population were collected and analyzed in 1998. The MX concentrations in plasma were compared with those in samples collected from the general population in 1992/1993. In order to study possible routes of exposure, we also analyzed perfumes (n = 8), various body-care products (n = 17), and detergents (n = 5) in the households from the persons who were exposed in 1998. The body-care products or the detergents were used every day or at least 3 -4 times per week.
Results and discussion: A remarkable decrease in MX levels was found on comparing the values from 1992,1993 and 1998. In 1998 12% (five out of 41) of the samples analyzed yielded positive results for MX (median: <0.1 microg/l, range: <0.1-0.29 microg/l), while in 1993 MX was found in 92% (66 out of 72) of the samples (median: 0.24 microg/l, range: <0.1- 1.12 microg/l). The observed decrease is explained by the discontinued use of MX in detergents in Germany since 1993. As a consequence, no MX could be found in the investigated detergents in the present study. However, MX could be analyzed in at least one perfume and/or perfumed bodycare product of the exposed individuals. The concentrations were in the range between 8.8 and 28.8 mg/kg in the investigated products. Because other confounding factors, e.g. diet and occupational exposure, could be excluded, the results point to the possibility that MX can be taken up through the skin. However, the small number of investigated persons limits this assumption.