N,N,N',N'-tetramethylhexamethylenediamine

Endpoint summary

Description of key information

Acutely toxic for aquatic organisms.

Additional information

Short-term toxicity to fish

A 96 hour acute toxicity study was conducted with N,N,N',N'-Tetramethylhexamethylenediamine (TMHDA, CAS 111 -18 -2) tested on Carp, in accordance with OECD guideline 203 and EEC Directive 92/69, Part C.1. to determine the ability of the test substance to produce toxic effects and determine the LC₅₀ at all observation timepoints. The test was conducted with carp

exposed to concentration ranging from 10 to 100 mg/L in a semi-static test system with daily renewal of the test solutions.

The LC₅₀for carp exposed to TMHDA was 75 mg/L (nominal, analytically verified) with 0% mortality at 56 mg/L and 100% mortality at 100 mg/L (Tosoh Europe B.V., 1995, report no. 146385). These mortality results were observed after 24 hours of exposure. No additional mortality was recorded during the remaining testing period.

In addition, a GLP-guideline study by BASF AG (1987, report no. 10F0181/875068) was performed, testing the acute toxicity of N,N,N',N'-Tetramethylhexamethylenediamine towards Leuciscus idus. The concentrations were not analytically verified, 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).

No effect was observed in pH-adjusted test solution with a concentration of 100 mg/L. Thus, the mortality in the study mentioned above is considered to be caused by the high pH. Therefore, the LC50 is supposed to be higher than 100 mg/L if pH-adjusted.

In conclusion, TMHDA is considered to be with high probability acutely not harmful to fish.

Long-term toxicity to fish

The results from short-term toxicity tests on fish, Daphnia and algae demonstrate that invertebrates are the most sensitive trophic level tested.

Therefore, it may be concluded that results from a long-term test in fish would not reveal a greater hazard than already determined by the available acute and chronic data.

Moreover, the chemical safety assessment for the substance demonstrates that

1) the exposure levels estimated in all relevant scenarios do not exceed the appropriate PNEC, and 2) the likelihood and severity of an event occurring due to the physicochemical properties of the substance in the aquatic environment are negligible; therefore, the criteria for adaptation are met.

Specifically, all risk characterization ratios are under 1.0; and there are no physicochemical hazards identified for this substance in the aquatic environment.

Therefore, and for reasons of animal welfare, a chronic test on fish is not provided.

Short-term toxicity to aquatic invertebrates

To determine the short-term toxicity of N,N,N',N'-Tetramethylhexamethylenediamine (TMHDA; CAS 111 -18 -2) to aquatic invertebrates, a 48-hr acute Daphnia magna toxicity study was conducted according to EPA guideline 797.1300. Nominal test concentrations ranged from 0.313 mg/L to 20.0 mg/L. The test system was semi-static, as test solutions were renewed after 24 hours. Adjustment of pH was not specfied, but measured pH values ranged between 7.6 and 7.9. The number of immobile animals in each test vessel as well as any abnormal behaviour were recorded at 0, 24 , and 48 hours. The 48 -hour EC50 was estimated to be 6.94 mg/L based on measured concentrations (Danish EPA 2000; report no. 81089/270).

In conclusion, TMHDA is considered to be acutely toxic for aquatic invertebrates.

Long-term toxicity to aquatic invertebrates

The long-term toxicity of N,N,N',N'-Tetramethylhexamethylenediamine (CAS 111 -18 -2) was assessed in an OECD 211 reproduction test (under GLP) using Daphnia magna as test organism (BASF SE 2013, report no. 51E0487/11E119). Daphnia were exposed to the test substance at nominal concentrations ranging from 0.10 to 4.6 mg/L. Parent mortality, abnormal effects and numbers of live and dead offspring were assessed every day. Test concentration analyses was carried out by HPLC.

The 21 -day NOEC for reproduction was found to be 1.0 mg/L and the EC10 was 0.86 mg/L. The 21 -day NOEC for mortality was 2.2 mg/L and the EC10 3.03 mg/L. The results are based on analytically verified time-weighted average concentrations, the pH in the test solutions was not adjusted.

Toxicity to aquatic algae and cyanobacteria

A study was performed according to OECD 201 under GLP conditions regarding the toxic effect of N,N,N´,N´-Tetramethyl-1,6-hexanediamine (TMHDA, CAS 111 -18 -2) towards algae (BASF SE, 2012; report no. 60E0487/11E118). The test species was Pseudokirchneriella subcapitata. The test concentrations were analytically verified. In inoculated samples the measured concentrations were 53 to 80% of the nominal concentration at the end of exposure. Analysis of uninoculated samples from the end of exposure showed that concentrations were within ±20% of nominal concentrations. This demonstrated that the decrease was due to binding of the test substance to the algal biomass. Therefore, the concentrations were stable and the effect values were given based on the nominal concentrations. The 72 -h effect values are as follows: ErC10 = 13.5 mg/L, ErC50 155 mg/L (BASF SE, 2012; report no. 60E0487/11E118).

In conclusion, the substance is with high probability acutely not harmful to algae.

Toxicity to microorganisms

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 3 -h 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).