No. 1031 - Miljøstyrelsen

Table 2.6
Consumption of siloxanes in Denmark 2002
Application area Consumption Percentage Uncertainty * Type of siloxanes
42
Tonnes/year
Sealants used for construction 920 29 Low Elastomers
Paints, inks and coatings 200 6 Medium Resins, elastomers
Cosmetics and toiletries 240 8 Medium Fluids, volatile fluids
Wax, polishes and cleaning agents 100 3 Medium Fluids, volatile fluids
Mechanical fluids and heat transfer fluids 50 1.6 Medium Fluids
Textile applications 380 12 High Fluids, elastomers
Processing aids 470 15 Medium Fluids
Paper coating 210 7 Medium Fluids
Health care 110 4 High Elastomers, fluids
Other uses of silicone elastomers 390 13 Medium Elstomers
Other uses of silicone fluids 50 1.6 High Fluids
Total 3,120 100
* Uncertainty indication:
Low : the right value is most probably within a range of x ±25%
Medium: the right value is most probably more than half and less than twice the best estimate
High: the right value may be less than half or more than twice the best estimate
In the present study it has not been possible to obtain a detailed split of the
different types of siloxanes on application areas. A study of the fate of the siloxanes
in the USA may though give an indication of the fate of the siloxanes
in Denmark (Allen et al. 1997). The main source of siloxanes to the air is the
volatile siloxanes of which 92% is released to the air by use. Polydimethylsiloxane
with modifications (silicone oils) are the main source of siloxane releases
to wastewater, as about 25% of the total is discharged to wastewater
treatment plants. Another 21% is "dispersed" and may end up in water bodies,
on the ground, etc.
Silicone resins and elastomers mainly end up in solid waste for incineration,
landfilling or recycling.
Table 2.7
Environmental loadings of industrial siloxanes for the USA in 1993 (based on Allen et
al. 1997) (x 1000 t)
Volatile
methylsiloxane
Polydimethyl
siloxane
Modified
polydimethylsiloxane
*
Polyether
methylsiloxane
Silicone resins
Silicone elastomers
Wastewater treatment plants 0.65 13.59 0.74 2.69 0.00 0.00
Landfilled/incinerated/recycled 0.70 24.81 3.33 7.21 2.42 89.13
Dispersed 0.25 13.38 0.29 0.00 0.31 0.00
Soil 0.0o 0.00 0.01 0.34 0.00 0.00
Air 18.10 0.00 0.00 0.00 0.00 0.08
Total 19.71 51.78 4.37 10.24 2.73 89.21
* Modified polydimethylsiloxanes include: methyl(hydrido)siloxanes, methyl(vinyl)siloxanes,
methyl(alkyl)siloxanes, methyl(phenyl)siloxanes, methyl(trifluoropropyl)siloxanes, and
methyl(aminoalkyl)siloxanes. These are treated as a group, because their physico-chemical properties
(which dictate their fate) are similar to PDMS and to each other.
The major release/disposal routes and risk of consumer exposure is summarised
in Table 2.8 below.