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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Endpoint summary

Administrative data

Description of key information

Additional information

The toxicity of cloquintocet-mexyl to fish, aquatic invertebrates, algae, plants and microorganisms has been investigated in reliable guideline studies.


Toxicity to fish has been tested for four different species. The lowest reliable value for short term toxicity to fish was 14 mg/L (Ictalurus punctatus). Longer-term toxicity to Oncorhynchus mykiss was also investigated in an OECD 204 prolonged study and provided a 21-day NOEC value of 1.26 mg/L, based on growth rate inhibition. However, in accordance with ECHA R.7b guidance, the NOEC from this study was not considered as true chronic endpoint.


Daphnia magna was chosen as test species for the evaluation of the toxicity of cloquintocet-mexyl to aquatic invertebrates. LC50 for short term toxicity is 100 mg/L and 21-day NOEC has been determined to be of 0.437 mg/L.


Toxicity to algae has been investigated for green algae (Scenedesmus subspicatus), blue-green algae (Microcystis aeruginosa) and diatoms (Navicula pelliculosa). The selected values for this endpoint are an ErC50 of 1.4 mg/L (mean measured) and a NOEC of 0.09 mg/L (calculated mean measured, based on nominal of 0.2 mg/L), both reported for Scenedesmus subspicatus.

The toxicity of cloquintocet-mexyl to aquatic plants (Lemna gibba) has been evaluated in a 14 day study. The key value used in the chemical safety assessment is the EC50 of 0.42 mg/L, based on frond density and biomass.


Toxicity to microorganisms has been investigated in a guideline study, based on the respiration of activated sewage sludge, and a NOEC value of 1000 mg/L was determined.