No. 1031 - Miljøstyrelsen

Table 4.1
PBT profiler results for selected siloxanes (based on U.S. EPA 2003)
Chemical name CAS no. Synonymous LOG Kow BCF
Bioconcentration-factor
Octamethylcyclotetrasiloxane
Decamethylcyclopentasiloxane
556-67-2 Part of cyclomethicone
Cas. no 69430-24-6
541-02-6 Part of cyclomethicone
Cas. no 69430-24-6
Fish ChV *
(mg/l)
Half-life
water/
sediment
(days)
5.1 1,700 0.058 38 / 340
5.2 2,000 0.021 38 / 340
Hexadimethyldisiloxane 107-46-0 4.2 340 0.062 15 / 140
Octamethyltrisiloxane 107-51-7 4.8 990 0.028 38 / 340
1,1,3,3-tetramethyl-1,3diphenyl
disiloxane
1, 1, 5, 5, 5- hexamethyl- 3phenyl-
3- [(trimethylsilyl)oxy]
trisiloxane
56-33-7 Phenyl dimethicone 7.2 35,000 0.00082 38 / 340
2116-84-9 Phenyl trimethicone 7.2 40,000 0.0012 38 / 340
CvH: Chronic Value (ChV) is the same as the chronic NEC (No effect concentration). US EPA
uses the following criteria for Fish ChV (mg/l):
> 10 mg/l: Low Concern
0.1 - 10 mg/l: Moderate Concern
< 0.1 mg/l: High Concern
4.3 Aquatic toxicity data for octamethylcyclosiloxane and PDMS
The environmental fate and effects of volatile methylsiloxanes (mainly cyclosiloxanes)
and polydimethylsiloxane (PDMS) have been reviewed by Hobson
et al. (1997) and Fendinger et al. (1997), respectively.
A summary of aquatic toxicity data for octamethylcyclosiloxane is shown in
Table 4.2 whereas toxicity data for PDMS is shown in Table 4.3.
Table 4.2
Summary of octamethylcyclosiloxane aquatic toxicity data (Hobson et al. 1997)
Species Test type(time) NOEC (µg/L) L(E)C50 or LOEC
(µg/L)
Rainbow trout Acute (14 d) 4.4 µg/L LC50 = 10 µg/L
Sheepshead minnow Acute (14 d) 6.3 µg/L * LC50 > 6.3 µg/L *
Daphnia magma Acute (48 h) 15 µg/L * EC 50 > 15 µg/L *
Mysid shrimp Acute (96 h) 9.1 µg/L * LC50 > 9.1 µg/L *
Rainbow trout Chronic (90 d) 4.4 µg/L * -
Daphnia magma Chronic (21 d) 7.9 µg/L * LOEC = 15 µg/L
* This concentration is the mean value measured in the highest exposure level.
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