Registration Dossier
Registration Dossier
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EC number: 911-381-6 | CAS number: -
Endpoint summary
Administrative data
Description of key information
Additional information
There are no reliable aquatic toxicity data available for the registration substance Reaction Mass of 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinylcyclopentasiloxane and 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl cyclotetrasiloxane as a whole, therefore good quality data from Constituent 2 (Vi4-D4) and read-across from a structural analogue of Constituent 1 have been used to assess short-term aquatic toxicity.
Reliable short-term toxicity tests results are available for invertebrates (Daphnia magna) and algae (Pseudokirchneriella subcapitata) for decamethylcyclopentasiloxane (D5, 541-02-6), read across to Constituent 1, Vi5-D5. The relevant short-term values are:
Daphnia: EC50 (48 h): >2.9 µg/l; NOEC: ≥2.9 µg/l.
Algae: EC50 (96 h): >12 µg/l; NOEC: ≥12 µg/l.
Reliable short-term toxicity tests results are available for invertebrates (Acartia tonsa) and algae (Skeletonema costatum) for Constituent 2, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (Vi4-D4, CAS 2554-06-5). The relevant short-term values are:
Acartia tonsa: LLC50 (48 h): 272 mg/l (loading rate WAF) (>LoS); NOELR: 100 mg/l (>LoS).
Algae: EL50 (70.5 h): >988 mg/l (loading rate WAF) (>LoS); NOELR of ≥988 mg/l (>LoS).
The available short-term aquatic toxicity data indicate that there are no effects on aquatic organisms at the limit of solubility of the substance in water.
No long-term aquatic toxicity data are available for the registration substance. Although this is not a requirement at this annex level, long-term tests should be considered because the substance is poorly water soluble. If only short-term data are provided, a “safety net” classification Category Chronic 4 could apply because the substance is poorly soluble and shows no acute toxicity up to the limit of water solubility, is not rapidly degradable and has a log Kow >4. Long-term aquatic toxicity studies have therefore been included.
Reliable long-term toxicity tests results are available for fish (Oncorhynchus mykiss) and invertebrates (Daphnia magna) for decamethylcyclopentasiloxane (D5, 541-02-6), read across to Constituent 1, Vi5-D5. The relevant long-term values are:
Fish: NOEC (90-day): ≥14 µg/l.
Daphnia: NOEC (21-day): ≥15 µg/l.
Reliable long-term toxicity tests results are available for fish (Oncorhynchus mykiss) for octamethylcyclotetrasiloxane (D4, CAS 556-67-2), read across to Constituent 2, Vi4-D4. The relevant long-term value is:
Fish: NOEC (93-day): ≥4.4 µg/l.
A reliable long-term invertebrate toxicity data is available for Constituent 2 of the registration substance, 2,4,6,8-tetramethyl-2,4,6,8-tetravinyltetrasiloxane (Vi4-D4, CAS 2554 -06-5). The relevant long-term value is:
Daphnia: NOEC (21-day): ≥0.00378 mg/l.
The available long-term aquatic toxicity data indicate that there are no effects on aquatic organisms at the maximum achievable concentration of the test substance in test media.
Refer to IUCLID Section 6 Ecotoxicological Information discussion for the approach to chemical safety assessment and justification for read-across.
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