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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

EC50 72h (freshwater OECD 202 study on Desmodesmus subspicatus) : > 100 mg/L
NOEC 72h (freshwater OECD 202 study on Desmodesmus subspicatus) : > 100 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

One valid experiment was performed.

The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L.

No statistically significant inhibition of algal growth was observed.

At the beginning and at the end of the test, the content of the test item in the test solutions was estimated using DOC-determination.

Because of the very low solubility in test medium, no calculation from carbon content of the test item and DOC measurement was possible. The measured DOC concentrations in the treatments were in a similar low range as the blank control. After 72 hours the measured DOC in the blank control was unexpected high. This was probably caused by a contaminated measuring vial. As algal growth was normal and the measured DOC at the start of the test was in a normal range, this can be stated as uncritical.

Therefore, the determination of the biological results was based on the nominal concentration.

This is in agreement with the OECD guidance document no. 23, where is stated: “For tests with chemicals that cannot be quantified by analytical methods, the effect concentration can be expressed based on the nominal concentrations (loading rates).”


The 72h-EC50s of potassium dichromate were determined in a separate reference test. For the estimation of the 72h-EC50s of the positive control, the fits showed sufficient statistical correspondence of the data with the dose-response-equation. The values were within the range of the laboratory.

All validity criteria were met.

No observations were made which might cause doubts concerning the validity of the study outcome. The result of the test can be considered valid.