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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

A LC50 of 37.8 mg/L in 96 hours was determined in a test with Fathead Minnow in the presence for benzyldimethylamine (Geiger, 1986). This value is further supported by additional short therm toxicity to fish studies.

Key value for chemical safety assessment

LC50 for freshwater fish:
37.8 mg/L

Additional information

Key study:

In a 96-h acute toxicity study, Fathead Minnow (Pimephales promelas) were exposed to benzyldimethylamine at nominal concentrations of 14.2 mg/L, 21.8 mg/L, 33.6 mg/L, 51.7 mg/L and 79.5 mg/L under static conditions. The 96-h LC50 was 37.8 mg/L, based on mortality. Affected fish lost schooling behavior, swam near the tank surface, and were overreactive to external stimuli. Equilibrium loss was not observed prior to death. The pH of the stock solution was adjusted to that of lake water with HCl (Geiger, 1986).

Supporting studies:

- In a supporting study (BASF, 1987) golden orfe were tested in a static freshwater test. In non pH adjusted water a LC0 of 10 mg/L and a LC100 of 46.4 mg/L were measured, whereas in adjusted water also a LC0 of 10 mg/L and a LC100 of > 100 mg/L was noted. In both cases no exact LC50 was derived. This study shows that the toxic effects are mainly attributed to the change of pH. The values with adjusted pH strongly support the findings of the key study.

- In a static freshwater test by Bayer (1979) with Leuciscus idus only a LC0 of 20 mg/L could be detected. No information about pH adjustment was given.

- In a 48 h semistatic freshwater test with Oryzias latipes (MITI, 1992) an LC50 of 59.3 mg/L. No information about pH adjustment was given.

Conclusion:

The LC50 value of 37.8 mg/L determined in the key study is further strengthened by the findings in the supporting studies. Lower values found in the study by BASF (1987) are due to non adjusted pH. With an adjusted pH the study by BASF (1987) is in line with the key study, where also an adjustement of the pH was done.