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Short-term toxicity to aquatic invertebrates

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Description of key information

For this endpoint information from a structural similar compound is available. This study for this similar compound was performed according to GLP and the methods applied are fully compliant with OECD TG 202.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
100 mg/L

Additional information

Justification for read across for short-term toxicity to aquatic invertebrates

Type of read across:one-to-one

Based on:

(1) Chemical similarity
The surrogate (CAS: 174350-05-1) provides all main chemical features present in the dossier compound (CAS: 124729-02-6). Both substances share typical structural features for liquid crystals, i.e. one phenyl ring coupled via single bond to a cyclohexyl ring. The phenyl ring shows a fluoro substition (dossier compound: n=2, surrogate: n=2) and an alkyl etherof equal chain length (n=2). The cylohexyl ring exhibits a para alkyl substitution of different chain length (dossier cpd.: n=5; surrogate: n=3). Overall this almost perfect match results in a high chemical similarity score of 1.00 (Tanimoto).

(2) Physicochemical key parameters relevant for bioavailability
Target: 124729-02-6 Source: 174350-05-1
Phenyl cyclohexyl core
Liquid crystalline properties
Water solubility
< 0.03 mg/L
<0.13 mg/L

Both compounds show liquiid crystalline properties. The similarity in chemical structures (see top 1) is reflected in a high physicochemical similararity relevant for bioavailability, such as logP and water solubility.

(3) Relevant biological response data and read across
Target: 263017-37-4 Source: 174350-05-1
BCF < 2000
BCF < 2000
NOEC > 100 mg/L
NOEC > 100 mg/L
Long Term Fish Toxicity from OECD TG 305
NOEC > water solubility limit
NOEC > water solubility limit
data gap
NOEC > 100 mg/L (nominal)

The source and the target compound give the same response in OECD 305 and and OECD 203 studies. In addition no toxicity was observed in fish after 28 days exposure 0.5 mg/L in BCFD studies.
The source compound (CAS: 174350-05-1) was tested in a GLP compliant test according to OECD TG 202. No effects have been detected in this assay up the limit of water solubility.

(4) Conclusion
Due to the high chemical similarity and the almost identical phys-chem profile, and identical response in biological assays, a read across from the source compound data OECD TG 202 to fill the data gap for the endpoint of short-term toxicity to aquatic invertebrates for the target chemical is justified.

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