Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Two toxicity tests with algae were performed. Both tests were well described and performed according OECD guideline 201 applying GLP conditions both should have a high Klimisch score. The study by Gancet (2009) however, gave results which are typical for what can go wrong when tests are performed with these difficult substances in reconstituted lab water. The test solutions are not stable and the exposure is unrealistic.  Thus for risk assessment purposes, the study where the bulk approach for testing (with river water) was implemented with a 72 hr ErC10 of 34.1 ug/L  and 72 hr ErC50 of 86.7 ug/L is used.

Key value for chemical safety assessment

EC50 for freshwater algae:
86.7 µg/L
EC10 or NOEC for freshwater algae:
34.1 µg/L

Additional information

Two toxicity tests with algae were performed. Both tests were well described and performed according OECD guideline 201 applying GLP conditions both should have a high Klimisch score. The study by Gancet (2009) however, gave results which are typical for what can go wrong when tests are performed with these difficult substances in reconstituted lab water. The test solutions are not stable and the exposure is unrealistic. The exposure concentration was only measured at the beginning and end of the test and the concentrations observed at the end are all below the LOD. No intermediate measurements were performed and it is therefore unclear what the actual exposure was during the test. The approach followed is not suitable for this test substance type. In addition basing the T=72 measurements on 1/2 the DL or QL is not considered realistic or appropriate for the test substance. The reliability of the result of this study is thus low. For classification and labeling purposes the study can be used as a worst-case. Application of bulk approach for algae testing is considered more realistic for this test chemical and the use of river water stabilizes the test substances in the test solution. Thus for risk assessment purposes, the study following the bulk approach (with river water) with an 72 hr ErC10 of 34.1 ug/L is used.