Benzyl-C12-14-alkyldimethylammonium chlorides

Toxicity to aquatic algae and cyanobacteria

Description of key information

The 96 or 72 hour EC50 values for growth inhibition of freshwater algae exposed to C12-16 ABDAC ranged from 0.03 to 0.049 mg a.i./L and the EC10/LC10 or NOEC ranged from ≤ 0.0012 to < 0.0025 mg a.i./L. The 72 hour ErC50 value for growth inhibition of marine algae exposed to C12-14 ADBAC was 0.26 mg/L (0.207 mg a.i./L), the ErC10 for growth rate was 0.12 mg/L (0.096 mg a.i./L) and the NOEC was 0.04 mg/L (0.03 mg a.i./L).

Key value for chemical safety assessment

EC50 for freshwater algae:

0.03 mg/L

EC50 for marine water algae:

0.207 mg/L

EC10 or NOEC for freshwater algae:

0.009 mg/L

EC10 or NOEC for marine water algae:

0.096 mg/L

Additional information

Toxicity of C12-16 ADBAC to Selenastrum capricornutum was determined over an exposure period of 96 hours according to OECD guidelines. The test was conducted at the nominal concentrations of 0, 0.005, 0.015, 0.045, 0.136 and 0.407 mg/L of the test substance. Analytical determination was performed. The EbC50 and ErC50 (0-96 hours) were 0.02 mg/L (equivalent to 0.01 mg a.i./L) and 0.06 mg/L (equivalent to 0.03 mg a.i./L), respectively. The LOEC was 0.005 mg/L (equivalent to 0.0025 mg a.i./L). The NOEC was < 0.005 mg/L (equivalent to 0.0025 mg a.i./L). Chemical analysis of duplicate samples taken at the beginning (96% recovery) and at the end (98% recovery) of the test indicated that the exposure concentrations were substantially achieved (Kroon AGMet al.,1996).

In another OECD guideline study, the toxicity of C12-16 ADBAC to fresh water algae Selenastrum capricornutum was determined over an exposure period of 72 hours. The test was conducted at the nominal concentrations of 0, 3.7, 13, 24, 43, 136 and 431 µg a.i./L. Concentrations were analytically determined at the start of the test and after 23, 47 and 71 hours of incubation. Algal growth was determined by electronic particle counting after 0, 23, 47 and 71 hours incubation. The ErC50 and EbC50 (0-72 hours) were 49 and 14 µg a.i./L, respectively. The NOEC≤1.2 µg a.i./L. Test substance concentrations were found to be relatively stable during the test and the mean measured test substance concentrations of 0, 1.2, 5.1, 11, 22, 98 and 382 µg/L were used for calculation of effect parameters. Statistical assessment of data by application of parametric model indicated a significant effect on the growth rate only. The ErC50 value of 0.049 mg a.i./L was therefore assessed to best represent the effect of C12-16 ADBAC on algal growth (Mayer Pet al.,2001).

In a further study, the toxicity of C12-14 ADBAC to Skeletonema costatum (marine algae) was determined during an exposure period of 72 hours. The test was conducted at nominal concentrations of 0, 0.1, 0.5, 2.5 and 10 mg/L. Analytical determination was not performed. The cell density was measured by fluorescence. The ErC50 and ErC10 (72 h) were 0.26 and 0.12 mg/L respectively (equivalent to 0.207 and 0.096 mg a.i./L), respectively. The NOEC was 0.04 mg/L (equivalent to 0.032 mg a.i./L) (Sundfor I, 2004).