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Description of key information

The influence of Mackam LSB-50 on the respiration rate of activated sludge was investigated after a contact time of 3 hours in accordance with OECD 209 and GLP principles. The substance was not toxic to waste water (activated sludge) bacteria at a concentration of 449 mg test item/L (corresponding to 160 mg active ingredient/L). A respiration inhibition of 50% was observed at 2571 mg/L of test item (corrsponding to 915 mg active ingredient/L).  

Key value for chemical safety assessment

EC50 or LC50 for microorganisms:
915 mg/L
EC10, LC10 or NOEC for microorganisms:
160 mg/L

Additional information

The inhibition effect of test item on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3 -hour respiration inhibition test according to the OECD Guidelines for testing of Chemicals, No. 209 "Activated Sludge, Respiration Inhibition Test", adopted 2010. The test was performed in compliance with GLP principles.

Based on the results of range-finding test a definitive test with the following nominal test item concentrations, with three replicates per concentration, was performed : 72, 180, 449, 1124, 2809 mg test item/L corresponding to 25.6, 64, 160, 400 and 1000 mg active ingredient (lauramidopropyl hydroxysultaine)/L.

As a positive control, the reference item 3,5 -dichlorophenol was tested under identical test conditions, at concentrations of 3.2, 10 and 32 mg/L (all single replicates).

Six blank controls, containing an equal volume of activated sludge and synthetic medium but no test or reference item, were included in the definitive test. All the validity criteria are fulfilled.

 

The 3 -hour NOEC and ECx-values were as follows:

NOEC = 449 mg test item/L (160 mg active ingredient/L)

EC10 = 825 mg test item/L (294 mg active ingredient/L)

EC50 = 2571 mg test item/L (915 mg active ingredient/L)

 

The test item has no inhibitory effect on the respiration rate of activated sludge after the incubation period of three hours up to 449 mg test item/L, corresponding to 160 mg active ingredient/L.