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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

In guideline study conducted with structurally similar test substance tricetylmethyl ammonium chloride, the 96-h EbC50 and ErC50 of tricetylmethyl ammonium chloride to S. capricornutum were found to be 0.11 and 0.18 mg a.i./L, respectively. Further, based on a good quality and reliable OECD guideline study conducted with structurally similar test substance C18 TMAC, the EbC50 (0 -72 h) and ErC50 for S. capricornutum were 0.05 and 0.08 mg a.i./L, respectively. The NOEC for effect on algal growth and growth rate was determined to be 0.04 mg a.i./L.

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
0.08 mg/L
EC10, LC10 or NOEC for freshwater algae:
0.04 mg/L

Additional information

A guideline study was conducted to evaluate the toxicity of the structurally similar tricetylmethyl ammonium chloride to Selenastrum capricornutum under static conditions. Based on the results of a range-finding test,S. capricornutum was exposed to the test substance at nominal concentrations of 0.035, 0.071, 0.142, 0.283 and 0.566 mg/L. Chemical analysis, using HPLC, of duplicate samples was taken at the beginning of the test indicated that the exposure concentrations were substantially achieved (85 - 99% of the nominal values). The concentrations at the end of the test were strongly decreased (21 -67% of the nominal values), probably due to adsorption of the test substance to the test flask walls. Thus, EC values were calculated based on the nominal, rather than measured, concentrations. The toxicity of the test substance to exponentially growingS. capricornutum was determined over an exposure period of 96 hours. The test was performed using six replicates for the control and three replicates for each concentration. All the validity criteria were fulfilled. Under the test conditions, the EbC50and ErC50of the test substance at 96 hours were found to be 0.11 and 0.18 mg a.i./L, respectively (Kroon AGM and Geurts MGJ, 1994).

In another guideline study, the toxicity of structurally similar C18 TMAC to exponentially growing algae Selenastrum capricornutum over an exposure period of 72 h was evaluated. In the range finding test, at nominal test concentrations of 1, 10 and 100 mg/L, growth of the algae was totally inhibited. Therefore, in the definitive test the algae were exposed to the nominal concentrations of 0.01, 0.02, 0.04, 0.08 and 0.16 mg/L. Algal cell concentrations were determined spectrophotometrically. All the validity criteria were fulfilled but no chemical analysis of the test concentration was performed. Under the study conditions, the EbC50(0 -72 h) and ErC50of test substance forS.capricornutum were 0.05 and 0.08 mg a.i./L, respectively. The NOEC for effect on algal growth and growth rate was determined to be 0.04 mg a.i./L (van Ginkel CG, 1990).