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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Pseudomonas cell multiplication inhibition test conducted under GLP conditions

Key value for chemical safety assessment

EC50 for microorganisms:
690 mg/L
EC10 or NOEC for microorganisms:
12.5 mg/L

Additional information

A study was performed to assess the effect of Methyl n-Amyl Ketone on the growth of the bacteria Pseudomonas putida. The method followed that described in the German Water Hazard Classification Scheme (Bewertung Wassergefahrdender Stoffe, LTWS Nr. 10) and ISO 10712 "Determination of the inhibitory effect of water constituents on bacteria (Pseudomonas cell multiplication inhibition test)". Work was conducted in order to determine whether the test item was volatile under the experimental conditions employed in an Activated Sludge, Respiration Inhibition Test. The results indicated that significant losses of the test item would occur in an Activated Sludge Respiration Inhibition Test as this type of test uses a high rate of aeration. Therefore the study type was changed to an Acute Toxicity to Bacteria (Pseudomonas putida) Test (ISO 10712) as no aeration is used for this test. Due to the volatile nature of this test item the study was carried out in sealed vessels to minimise possible losses of the test item due to volatility. Following a preliminary range-finding test,Pseudomonas putidawas exposed to an aqueous solution of the test item at concentrations of 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50, 100, 200, 400, 800 and 1600 mg/l (three replicate flasks per concentration) for approximately 17 hours, at a temperature of 23 ± 1C. Exposure of Pseudomonas putida to the test item gave an EC10 of 52 mg/I and an EC50 of 690 mg/l and a NOEC of 12.5 mg/L.