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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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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Link to relevant study record(s)

Description of key information

The members of this category are gases at standard temperature and pressure and will predominantly partition to the atmosphere, which will limit their aquatic toxicity. Consequently, conducting aquatic ecotoxicity tests on these streams is technically difficult and based on exposure estimates the test is not relevant.


Due to the difficulty associated with conducting aquatic toxicity tests on these streams, experimental data are not available for the members of this category. In the absence of measured data, the use of QSAR to predict the ecotoxicity of representative constituents of these streams is an appropriate technique for aquatic toxicity and it is more appropriate to consider the toxicity of representative constituents of these streams.


ECOSAR v.1.11 (Epi Suite 4.1) has been used as key QSAR. The representative constituents of the category studied and used as supporting read-across are But-1-en-3-yne (CAS 689-97-4), But-1-ene (CAS 106-98-9), But-2-ene, cis- (CAS 590-18-1), But-2-ene, trans- (CAS 624-64-6), Buta-1,2-diene (CAS 590-19-2), Buta-1,3-diene (CAS 106-99-0), Butane (CAS 106-97-8), Prop-1-ene, 2-methyl- (CAS 115-11-7), and Propane, 2-methyl- (CAS 75-28-5).


The model predicted EC50 for short-term toxicity of representative constituents to aquatic algae and cyanobacteria to range from 12.405 mg/L to 47.248 mg/L, whereas the chronic value for long-term toxicity to aquatic algae and cyanobacteria was predicted to range from 3.459 mg/L to 10.932 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
12.405 mg/L
EC10 or NOEC for freshwater algae:
3.459 mg/L

Additional information

The ECOSAR class program has been developed primarily for the evaluation of neutral organic compounds and organic classes with excess toxicity. The QSARs in the ECOSAR program are developed for chemical classes based on measured test data that have been submitted by industry or they are developed by other sources for chemicals with similar structures, e.g., phenols.  Using the measured aquatic toxicity values and estimated Kow values, regression equations can be developed for a class of chemicals.  Toxicity values for new chemicals may then be calculated by inserting the Kow value into the regression equation and correcting the resultant value for the molecular weight of the compound.