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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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


In a 96-h acute toxicity study, rainbow trout (Oncorhynchus mykiss) were exposed to OPA (Octylphosphonic Acid) at 40 mg/L nominal concentrations (limit test) under semi-static conditions according to the OECD guideline N° 203 (1992). 

40 mg/L was considered to be the highest concentration which was possible to be dissolved in the media without precipitation of the substance. That why this test could be considered as a limit test.

The 96-h LC50was >40 mg/L

The NOEC values, based on mortality/sublethal effects, was 40 mg/L.

No sublethal effects were observed. Based on the results of this study, OPA would be not classified to fish.


The 48–hr-acute toxicity of OPA to Daphnia magna was studied under static conditions.  Daphnids were exposed to control and test chemical at nominal concentration of 1.0, 1.8, 3.2, 5.6, 10, 18 and 32 mg/L for 48 hr.  Immobility were observed daily. 

The 48– hour EC50was > 32 mg/L. 

The test was not carried at a concentration above than 32 mg/L because it was not possible to solubilize the subtance at a level upper than 32 mg/L in the medium (observations made during the range-finding study)


It satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.


Results Synopsis

Test Organism :Daphnia magna

NOEC:  3.2 mg.//L   

EC50: >32 mg/L



In a 72 hour acute toxicity study, the cultures of Pseudokirchneriella subcapitata were exposed to OPA at nominal concentrations of 1.0, 3.2, 10, 32 and 100 mg/L under static conditions in accordance with the OECD 201, after a range finding study at nominal concentration of 0.1, 1.0, 10 and 100 mg/L

Analytical verification showed an acceptable correlation between the nominal and the measured concentration.

The results were based on nominal concentration

The following results were determined:

NOEC Growth Rate and yield = 10 mg/L

EC 50 Growth rate= 40 mg/L with confidence limits of 35 -44 mg/L

EC 50 Yield = 23 mg/L with confidence limits of 20 -26 mg/L

All validity criteria were met, the test can be considered to be valid