No. 1031 - Miljøstyrelsen

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A possible estrogenic effect contributing to the reproductive toxicity of D4 is
debated. There seems however to be some indication that this toxicity may be
caused by another mechanism than estrogen activity.
Effects which based on the reviewed literature do not seem to be problematic
are acute toxicity, irritant effects, sensitization and genotoxicity.
Siloxanes are in general stable compounds that are very persistent in the environment.
The cyclic siloxanes and small-chain linear siloxanes are bioconcentrated
(bioconcentration factors for long-chained siloxanes have not been
assessed). The estimated bioconcentration factors (BCF) of the small siloxanes
range from 340 for HMDS to 40,000 for a phenylated trisiloxane
(phenyl trimethicone). The small phenylated siloxanes seem to have very high
BCF, and model estimates indicate that these substances are the most toxic
for aquatic organisms.
Alternatives to siloxanes for cosmetics and maintenance products
Traditionally when talking about substitution, the siloxanes have been on the
positive side, e.g. as alternatives to PCBs. The development of alternatives to
siloxanes has mainly focused on siloxanes used in cosmetics and breast implants.
Until now the absence of siloxanes in cosmetics has not been a competition
parameter in Denmark, but many - and in particular American producers
- use the Internet for advertising "silicone-free" hair care and skin care
products.
As cosmetics and maintenance products are among the most significant product
groups as to consumer exposure and releases to the environment, the assessment
of alternatives to siloxanes has focused on these groups.
The siloxanes have a number of properties which are not easily matched by
alternatives. For soaps and leave-on products (lotions and creams for skin) the
siloxanes e.g. can give the product the combination "smooth and soft feeling"
on the skin combined with the sense that the product does not feel greasy on
the skin after application. In particular the properties of the volatile cyclic siloxanes
are difficult to substitute. The price of the alternatives ranges from the
same as the price of the siloxanes to approximately the double price. The use
of alternatives will in general not require changes in production equipment.
Alternatives to siloxanes in cosmetics identified by enquiries to Danish producers
and suppliers are listed in Table 2.
The substitution of siloxanes has not had the particular attention of the producers
of cleaning and maintenance agents. Siloxanes used in cleaning agents,
waxes and polishes are in general different from the siloxanes used in cosmetics,
although some of the wanted properties are the same, for example shine,
spreadability and antifoaming. The identified alternatives are therefore also
quite different from the alternatives developed for cosmetic products. As for
alternatives to siloxanes in cosmetic products it is the general opinion in the
cleaning agent trade that siloxanes have some special qualities that cannot easily
be found in alternatives. These qualities are in particular as solvent, emulsifier,
anti-soiling and defoaming agents.
Identified alternatives to siloxanes antifoaming agents are non-ionic mineral
oils (tensides), paraffin oils, vegetable oils and block polymers consisting of
polyethylenglycol and polypropylenglycol. Alternatives to amino-functional