2,2,4(or 2,4,4)-trimethylhexane-1,6-diamine

Endpoint summary

Additional information

The aquatic toxicity of the substance was tested in Daphnia magna, algae, fish and aquatic microorganisms (Pseudomonas putida).

A growth inhibition study on alga was conducted in 2015. The toxicity of test item to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No. 761/2009/Method C.3.

The study was conducted under static conditions at five concentrations in a geometrical series with a dilution factor of 2.5 (nominal): 2.56 - 6.40 - 16.0 - 40.0 - 100 mg/L. Additionally the neutralized concentration level of 100 mg/L was tested. The measured concentrations in the old media (72 h) were in the range of 88 to 118 % of the nominal values of all concentrations so that all effect values are given based on the nominal test item concentrations.

In this study, the test substance was found to inhibit the growth of the freshwater green alga after 72 hours with the following effect values (based on nominal test item concentrations): The EC50-values with 95 % confidence intervals for inhibition of growth rate (ErC50) were 43.5 (40.1 – 81.3) mg/L. The NOEC-values for both inhibition of growth rate and yield after 72 hours were 16.0 mg/L. The highest test concentration (100 mg/L) tested at an initial pH value 8.1 caused a comparable inhibition of growth as the replicates without adjustment of the pH value.

The acute toxicity of the test item on Daphnia magna was investigated by Hüls AG (1996) in a 24 -h test according to national guidance documents (DIN 38412, part II). The EC50 (24 hours) was determined as 31.5 mg/L (CL: 38.9 - 34.2 mg/L) indicating that the test substance may be harmful to aquatic invertebrates.

The Daphnia magna Reproduction Test (semi-static, 21 d) was conducted according to OECD 211 (2012). Test species was Daphnia magna STRAUS (Clone 5). The study was carried out under semi-static conditions with concentrations ranging from 1.02 to 40.0 mg/l. The measured test item concentrations were all within ± 20 % of the nominal concentrations throughout the exposure period indicating that the test item concentrations were successfully maintained for the duration of the test.

Adult mortality was the most sensitive endpoint in this study. Based on the significant adult mortality the No Observed Effect Concentration (NOEC) after 21 days was assessed as 1.02 mg/L and the Lowest Observed Effect Concentration (LOEC) was assessed as 2.56 mg/L. Based on the nominal test item concentrations, the EC10 was determined as 1.02 mg/L. The EC50 was calculated to be 5.26 mg/L (95% confidence limits: 2.23 – 11.8 mg/L). Due to the lack of significant effects, no EC-values for the reproduction could be calculated.

The acute toxicity of the test item on Leuciscus idus melanotus was evaluated in a static fish test over a period of 48 hours (Hüls AG 1996). The test was conducted according to national guideline DIN 38412, part 15. The LC50 (48 hours) for fish was determined as 174 mg/L indicating that the test substance does not pose a significant hazard to fish.

The long-term effects on Danio rerio were studied in a fish early life stage test according to OECD 210. The test substance caused no significant effects on Zebrafish, 30 days post hatch. Based on the parameters hatch, growth (expressed as length and dry weight) and post-hatch survival (mortality) the overall NOEC (nominal, post hatch day 0 30) was 10.0 mg/L, corresponding to 10.9 mg/L (arithmetical mean). The overall LOEC (nominal, post hatch day 0 30) was > 10.0 mg/L, corresponding to > 10.9 mg/L (arithmetical mean).

The effects of the substance on Pseudomonas putida were investigated by Hüls AG (1993) according to DIN 38412, part 8 (national German guideline). Six concentrations + control were tested over a period of 16 hours. Two tests with and without pH adjustment were performed.

The EC50 for the test without pH adjustment was determined as 89 mg/L and the EC10 as 72 mg/L indicating that the test substance may be harmful to aquatic microorganisms.

Due to the basic properties of the test substance the concentrations used in the first test were rather low. Another test with higher concentrations was conducted and the pH of the stock solutions was adjusted to achieve a neutral value. The EC50 was determined as >10 g/L and the EC10 as 1469 mg/L.