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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

OECD Guideline 201, EU Method C.3, GLP, key study, validity 2:
- 72h-ErC10 = 0.162 (95% CL: 0.092-0.231) mg/L.
- 72h-ErC50 = 0.736 (95% CL: 0.590-0.922) mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
0.736 mg/L
EC10 or NOEC for freshwater algae:
0.162 mg/L

Additional information

One valid key study is available to assess the toxicity of Chimexane NB to the unicellular freshwater green algae Pseudokirchneriella subcapitata. This study was performed according to the principles of OECD 201 and EU Regulation 440/2008 Method C.3. with GLP statement.

The study was conducted under static conditions with an initial cell density of 5000 -10000 cells/mL (nominal). Five concentrations were tested in a geometrical series of: 0.032, 0.10, 0.32, 1.00, 3.20 mg test item/L. Three replicates were tested for the test item concentrations and six replicates for the control. Environmental conditions were determined to be within the acceptable limits.

The concentrations of the active substance were analyzed at test start and test end via LC-MS/MS. The measured concentrations at test start were in the range of 97 -119% of the nominal values. At the end of the test the active ingredient gave recoveries of 63 -98% in the test replicates prepared with algae. Additional replicates for determination of the test item after 72 h without algae gave recoveries of 91 -122 % of nominal values. All effect values are given based on nominal test item concentrations in the report, instead of measured concentrations. The endpoint values were recalculated using geometric mean measured concentrations with ToxRat Professional.

Chimexane NB was found to inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 h with the following effect values (geometric mean measured concentration) : The ErC10 and ErC50 values with 95% confidence intervals for inhibition of specific growth rate were 0.162 (0.092-0.231) mg/L and 0.736 (0.590-0.922) mg/L, respectively.