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Toxicity to microorganisms

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Description of key information

The inhibition of microorganisms by Dimethylbutylamine (free base) is considered to be moderate as long as the pH value is not increased above 9 or 10, based on observations with P. putida ( EC50 (16 hrs) 480 mg/L with the free base) and activated industrial sludge (respriation not affecte up to 800 mg free base/L, and 1000 mg/L when neutralised).

Key value for chemical safety assessment

EC50 for microorganisms:
480 mg/L
EC10 or NOEC for microorganisms:
292 mg/L

Additional information

The inhibitory effect of N,N-Dimethylbutylamine on cell proliferation of Pseudomonas putida was determined according to an acknowledged national test method, DIN 38412 Part 8. Based on biomass the EC10(16 hrs)was 292 mg/L and the EC50 (16 hrs)was 480 mg/L with the free base (BASF AG, 1991). The respiration rate of activated industrial sludge was not affected at 400 and 800 mg/L (BASF AG, 1986).

It is therefore concluded that water treatment plants are not adversely affected if the substance is introduced in moderate amounts that do not raise the pH value above 9 or 10.