Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

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  201.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater algae:
130 µg/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 ethoxy substitution in para position. The only difference in terms of chemical structure is the length of the alkyl moiety connected to the cyclohexyl ring in para position (surrogate: n=3; dossier compound: n=5).
Overall this almost perfect match results in a high chemical similarity score of 1.00 (Tanimoto).

(2) almost identical physicochemical key parameters relevant for bioavailability

Assay
Target: 124729-02-6 Source: 174350-05-1
Phenyl cyclohexyl core
yes
yes
Liquid crystalline properties
yes
yes
Water solubility
0,030 mg/L (EU A.6)
0,130 mg/L (EU A.6)
logP
> 6,5 (OECD 117, EU A.8)

> 5.7 (OECD 117, EU A.8)



(3) Relevant data of the source molecule
The source compound (CAS: 174350-05-1) was tested in a GLP compliant test according to OECD 202. No effects have been detected in this assay up the limit of water solubility. The NOEL of this study is larger than 100 mg/L.


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