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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The observed endpoints effects of the test item on the growth of the freshwater green algal species Pseudokirchneriella subcapitata are summarized as: ErC10=0.083, ErC50=0.25, NOEC 0.017, LOEC 0.031 mg/L. The biological results were related to the geometric mean of the concentrations measured.

Key value for chemical safety assessment

EC50 for freshwater algae:
0.253 mg/L
EC10 or NOEC for freshwater algae:
0.083 mg/L

Additional information

The impact of the test item on the growth of the freshwater green algal species Pseudokirchneriella subcapitata was investigated in a 72-hour static test according to the OECD Guideline 201 (2006) and the Commission Regulation (EU) No 2016/266, C.3, and following the GLP.

The nominal concentrations of the test item of 0.030, 0.090, 0.27, 0.81, 2.4, and 7.3 mg/L were tested in parallel with a control (test water without test item). A stock solution of the nominal concentration of 73 mg/L was prepared by dissolving 73.03 mg of the test item completely in 1000 mL of test water. This stock solution was serially diluted with test water to prepare the test media of the different test concentrations as stated above. For measurement of the actual concentrations of the test item, duplicate samples were taken from the test media of all test concentrations at the start and at the end of the test. As the test item is highly instable, additional stability samples were taken after 24 and 48 hours following the recommendation of the test guideline.

At the start of the test, the measured test item concentrations in the test media with the concentrations of 0.030 to 7.3 mg/L in the range of 81 to 100% of the nominal values). The results show the correct preparation of the test media. After 24 hours test period, the test item concentrations had strongly decreased. The measured concentrations after 24, 48 and 72 hours were 0.012, 0.017, 0.031, 0.15, 0.39 and 0.96 mg/L. The mean measured test item concentrations were calculated as the geometric mean of the concentrations measured at all sampling dates (0, 24, 48, and 72 hours). All the validity criteria were fulfilled according to the OECD guideline 201. The observed endpoints effects of the test item on the growth of the freshwater green algal species Pseudokirchneriella subcapitata are summarized as: ErC10=0.083, ErC50=0.25, NOEC 0.017, LOEC 0.031 mg/L. The biological results were related to the geometric mean of the concentrations measured.