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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriate low concentrations.

Key value for chemical safety assessment

EC50 for microorganisms:
750 mg/L
EC10 or NOEC for microorganisms:
64 mg/L

Additional information

The assessment of the toxicity of N,N,N',N'-Tetramethylhexamethylenediamine (TMHDA; CAS 111 -18 -2) to aquatic microorganisms is based on experimental data from a respiration inhibition test according to OECD 209, performed under GLP-conditions (BASF SE 2012, report no. 08G0487/11G080). Non-adapted activated sludge from a municipal wastewater treatment plant of Mannheim, Germany was used as inoculum. The 30 -min EC20 was determined to be 150 mg/L, based on nominal concentrations, indicating that no effect on the degradation activity is anticipated for activated sludge if TMHDA is introduced in appropriately low concentrations.

The data for the key study are supported by the results of a non-GLP study conducted according to OECD 209 (BASF AG 1987, report no. 01.449/86). Activated slugde from an industrial wastewater treatment plant was used as inoculum. The 30 -min EC20 was determined to be > 600 mg/L (nominal).

In both studies, the concentrations were not analytically verified during the test, but TMHDA is expected to be stable in water, as the substance is miscible in water (BASF SE 2013, report no. 11L00324), its vapor pressure is moderate (VP = 0.124 hPa @20°C, Notox Project 2006, report no. 461407) and its Henry's Law Constant is low (HLC = 7.57 E-03 Pa m³/mol @ 25°C, calculated with HENRYWIN v3.20, not in applicability domain, BASF SE 2016).