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Toxicity to microorganisms

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Description of key information

The effects of benzyldimethylamine to the population growth of Pseusomonas putida was determined according to Bringmann and Kühn (DIN 38412, part 8, 17 h). Benzyldimethylamine revealed an EC10 of 534 mg/L and an EC50 of 749.6 mg/L (BASF, 1987).

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
534 mg/L

Additional information

Key study:

A growth inhibition test according to Bringmann and Kuehn (German statndad DIN 38412, part 8) was conducted to assess the toxicity of Benzyldimethylamine to bacteria (Pseudomonas putida, strain DSM 50026). Nominal test concentrations were 0, 15.625, 31.25, 62.5, 125, 250, 500, 1000 mg/L. The growth inhibition was determined after a period of 17 hours. Benzyldimethylamine revealed an EC10 of 534 mg/L and an EC50 of 749.6 mg/L (BASF, 1987).

Supporting/disregarded studies:

- A respiration inhibition test according OECD 209 (activated sludge) was conducted to assess the toxicity of Benzyldimethylamine to bacteria. Nominal test concentrations were 0, 115, 269 and 575 mg/L. The growth inhibition was determined after a period of 30 min at a temperature of 20-25 °C. Benzyldimethylamine revealed an EC20 of 575 mg/L (BASF, 1987).

- A growth inhibition test according to Bringmann and Kuehn was conducted to assess the toxicity of Benzyldimethylamine to bacteria (Pseudomonas putida) (Bayer AG, 1979). Nominal test concentrations were 0, 1.96, 3.91, 7.82, 15.63, 31.25, 62.5, 125, 250, 500, 1000 mg/L. The growth inhibition was determined after a period of 16 hours. Benzyldimethylamine revealed an EC10 of 54 mg/L. This, non state of the art study was not taken into account in the risk assessment .

Conclusion:

The risk assessment for STP will be based on the growth inhibition test with Pseudomonas putida revealing an EC10 of 534 mg/L (BASF 1987). This value is supported by a respiration inhibition test (activated sludge according to OECD 209) with an EC20 of 575 mg/L (BASF, 1987). The study by Bayer AG revealed an EC10 of 54 mg/L and is thus contradictionary to both BASF tests. This non guideline and non GLP study is thus not taken into account for the risk assessment.