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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

In a guideline study, the EC50 for activated sludge following 3-hour contact time with C16-C18 TMAC was 42 mg a.i./L with 95% confidence limits of 15 and 133 mg/L. The EC10, EC20 and EC80 were 13, 20 and 91 mg a.i./L, respectively. C16-C18 TMAC is therefore considered harmful to activated sludge.

Key value for chemical safety assessment

EC50 or LC50 for microorganisms:
42 mg/L
EC10, LC10 or NOEC for microorganisms:
13 mg/L

Additional information

An activated sludge respiration inhibition test was performed with C16-18 TMAC according to OECD guidelines. The toxicity of the test substance to activated sludge was determined at a contact time of 3 hours, using various concentrations of the test substance. The inhibitory effect of the test substance at a particular concentration was expressed as a percentage of the two controls. The validity of the test was shown by two criteria. First, the EC50of the reference compound 3,5-dichlorophenol (15 mg/L) was within the prescribed range and secondly the control respiration rates were within 10% of each other. No analytical determination was performed for the test substance. The EC50of the test substance for activated sludge after 3 hours was 42 mg a.i./L with 95% confidence limits of 15 and 133 mg a.i./L. The EC10, EC20and EC80were 13, 20 and 91 mg a.i./L, respectively, (Geerts R, 2012).