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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Long-term toxicity to fish

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Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

No long-term toxicity to fish data are available with the registered substance.

The requirement for a long-term toxicity to fish test has been waived for the following reasons:

- 3-(Triethoxysilyl)propanethiol (CAS 14814-09-6, EC No. 238-883-1) is part of a class of thiol compounds which contain a terminal thiol (SH) group present on a Silicon side chain. The thiol group is a structural alert associated with enhanced toxicity inDaphnia(ECHA Guidance Chapter R.10). The substance is therefore very unlikely to be more toxic to fish thanDaphniaand any effect concentration derived in a long-term toxicity to fish study would not be lower than the results of a long-term toxicity toDaphniastudy.

A long-term toxicity to aquatic invertebrates study is available with the registered substance; a 21-day NOEC value of 0.081 mg/l was derived for the effects of the test substance on survival and reproduction ofDaphnia magna, and forms the basis of the chemical safety assessment.

- Short-term aquatic toxicity data are available with the registered substance and the structurally analogous read-across substance 3-(trimethoxysilyl)propane-1-thiol (CAS 4420-74-0, EC No. 224-588-5):

3-(triethoxysilyl)propanethiol (CAS 14814-09-6):

Fish (96 h): LC50 >2.55 mg/l, invertebrates (48 h): EC50 2.71 mg/l, algae (72 h): ErC50 32.2 mg/l, ErC10 11.8 mg/l and NOErC 4.8 mg/l.

3-(trimethoxysilyl)propane-1-thiol (CAS 4420-74-0):

Fish (96 h): LC50 439 mg/l, invertebrates (48 h): EC50 6.7 mg/l, algae (72 h): ErC50 931 mg/l, ErC10 92 mg/l and NOErC 40 mg/l.

Both substances contain a thiol (SH) group and both hydrolyse to 3-(trihydroxysilyl)propanethiol, which also contains the thiol group.

The experimental short-term toxicity data show that the most susceptible trophic level is invertebrates. ECHA guidance Chapter R.7b states that if there is compelling evidence to suggest that the fish value is likely to be at least a factor of about 10 less sensitive than invertebrates or algae there are no further requirements for fish testing. Because, in the interest of animal welfare, the short-term toxicity to fish test conducted with the registered substance was a threshold toxicity test, it is not possible to compare relative sensitivities of the test species (though the fish show no toxicity at the EC50 level for Daphnia). The inclusion of the read-across data allows for comparison of species sensitivity. The data demonstrate that the fish are more than a factor of 10 less sensitive than invertebrates.

A long-term toxicity to aquatic invertebrates study is available with the registered substance; a NOEC value of 0.081 mg/l (Noack 2022) was derived and forms the basis of the chemical safety assessment. An algal NOEC value is also available, although algae are less sensitive thanDaphnia.

- A high level of toxicity was demonstrated in the long-term toxicity toDaphniastudy with the registered substance. The NOEC derived in the study (21-day NOEC 0.081 mg/l) is used to derive aquatic PNECs as well as PNECs for the sediment and soil compartments using the equilibrium partitioning calculation. The resulting RCRs according to the exposure assessment are all <1, therefore further testing on long-term toxicity to fish is not considered necessary or justified on ethical grounds.