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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

In a growth inhibition test, Pseudomonas putida were exposed over 17 hours to the test substance according to DIN 38412 (Part 8). The EC10 was determined to be nominal 111.7 mg/L and the EC50 was determined to be also nominal 203.4 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
203.4 mg/L
EC10 or NOEC for microorganisms:
111.7 mg/L

Additional information

The objective of the key study according to the German Industrial Standard Part 8 was to determine the effect of different concentrations of the test substance on the growth inhibition of microbial inoculum, compared to the blank control. The test was conducted at concentrations of 0 (control), 31.25, 62.5,125, 250 500 and 1000 mg/L. The toxicity of the test substance was followed by exposing it to the microbial-inoculum of Pseudomonas putida over 17 hours. The EC10 was determined to be nominal 111.7 mg/L and the EC50 was determined to be also nominal 203.4 mg/L.

A supporting study of the test item was also performed according to the OECD 209. The toxicity of the test item was followed by exposing it to microorganisms from the effluent (active sludge) of an industrial waste water treatment plant over 30 minutes. The EC20 was determined to be greater than 1995 mg/L.

In addition to that several supporting studies with the surrogate test substance 3-aminopropyldiethylamine were performed. The most important supporting study of this read across substance according to the OECD 209 (1993) was performed to determine the effect of different concentrations of the test substance on the oxygen consumption of microbial-inoculum, compared to the blank control. The test was conducted at concentrations of 0 (control), 1, 10,100 and 1000 mg/L. The toxicity of the test substance was followed by exposing it to microorganisms from the effluent (active sludge) of a domestic waste water treatment plant over 30 minutes. The EC50 value of for the reference substance 3,5-dichlorophenol was determined to be 9 mg/L, which was within the acceptable limits, (5.0 to 30 mg/L) as specified in the Guideline. Thus, all validation criteria were fulfilled. Based on these results, the EC20 value was calculated to be greater than 1000 mg/L and the EC50 value was calculated to be 1000 mg/L.

Another supporting study of the surrogate test substance 3-aminopropyldiethylamine was carried out according to the German Industrial Standard DIN 38 412/9. The toxicity of the test item was followed by exposing it to Pseudomonas putida over 7 hours. The EC10 was determined to be nominal 76.1 mg/L and the EC50 was determined to be also nominal 100.5 mg/L.

In addition to this the surrogate test substance Diethylaminopropylamine toxicity has been investigated in a supporting study according to ISO 8192 with activated sludge from the BASF wastewater treatment plant. After 30 min, respiration was not inhibited at all test concentrations up to 1995 mg/L. But it is not indicated if the test solutions were neutralized.