Registration Dossier
Registration Dossier
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EC number: 203-161-7 | CAS number: 103-95-7
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
The valid OECD 201 study performed on Cylcamen Aldehyde Extra considered both the 72 hour and 96 hour timeframe. Herein, the end-point values derived for the 72 hour time-point are used in this dossier in view of the fact that this is the standard duration recommended under the OECD 201 test guideline. The 72h Growth Rate EC50 = 4.3 mg/L, EC10 = 2.6 mg/L and NOEC = 0.72 mg/L.
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 4.3 mg/L
- EC10 or NOEC for freshwater algae:
- 2.6 mg/L
Additional information
A study was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 761/2009 and the US EPA Draft Ecological Effects Test Guideline OPPTS 850.5400.
A decline in measured concentration observed in the range-finding test followed a concentration dependant pattern. Therefore it was considered likely that the test item was adsorbing to the algal cells present. Further study of samples without the presence of algal cells confirmed this theory. It was therefore considered appropriate to base the results on the geometric mean measured test concentrations using the 72 and 96 hour results obtained from the samples prepared with the omission of algal cells as these reflect more accurately the concentrations of test item to which the algae were exposed.
A positive control test showed that the use of a modified test system to reduce losses of test item through volatility (completely filled and sealed test vessels) had a slightly lowering effect on the EC50 values obtained, and, a notable effect on the No Observed Effect Concentration (NOEC) compared with that obtained in a conventional test system. As such it can be considered that the results obtained from the definitive test give a worst case result for the test item.
The preferred observational endpoint in this study is algal growth rate inhibition because it is not dependent on the test design (ECHA guidance Chapter R.7b v1.1).
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