Reaction products of 3-aminomethyl-3,5,5-trimethylcyclohexylamine with 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

Endpoint summary

Description of key information

In summary, the acute toxicity tests for the test item revealed an LC50 (96 h) of 1.62 mg/L in fish, an EC50 (48 h) of 1.59 mg/L in invertebrates and an EC50 (72 h, growth rate) of 3.13 mg/L in algae. The most sensitive test was the toxicity to Daphnia magna, with an EC50 of 1.59 mg/L, and this value was used for the calculation of predicted no effect concentrations (PNEC).

Additional information

Fish

Young fish were exposed to aqueous test media containing the test item at the nominal concentrations: 0.625; 1.25; 2.5; 5.0 and 10.0 mg/L. For the analysis of the test item concentrations, samples from the treatment groups and the untreated groups were taken at the start and at the end of the study. The analytically determined mean test concentrations in the analysed test media ranged from 90 % to 117 % at the start and from 62 % to 108 % at the end of the study. The deviation of the measured concentrations from the nominal values was higher than 20 % in some cases at the end of the study. Therefore all biological results are related to the geometric mean measured concentrations of the test item calculated by EXCEL Software Program. The corresponding measured mean concentrations were 0.477; 0.964; 2.64; 5.34 and 9.81 mg/L. The 96-hour LC50 was calculated to be 1.62 mg/L (95 % confidence intervals: 0.67 – 2.97 mg/L, SPSS+ statistical software program). The 96-hour NOEC (highest concentration tested without any toxic effect after the exposure period of 96 hours) and the 96-hour LC0 of the test item was determined to be 0.964 (nominal 1.25) mg/L. The 96-hour LOEC was 2.64 (nominal 2.5) mg/L. In this 96-hour static acute toxicity test to Zebrafish (Danio rerio) with the test item the LC50 values were in the range of 1 - 10 mg/L (Probit analysis). The overall NOEC was determined to be 0.964 mg/L.

Daphnia

The analytically determined test item concentrations in the analysed test media varied in the range from 90 % to 115 % at the start and from 63 % to 117 % at the end of the study in comparison to the nominal value.

The 48h-NOEC (highest concentration tested without toxic effects after the exposure period of 48 hours) of the test item to Daphnia magna was determined to be 0.705 (nominal: 0.826) mg test item/L. The observed 5 % mortality at this concentration level is in the control data range. The 48h-LOEC was 1.569 (nominal 1.818) mg test item/L. While the 48h-EC50 was calculated to be 1.59 mg/L (nominal: 1.75 mg/L); the 48h-EC0 of the test item was 0.288 mg/L (nominal 0.376 mg/L) and the 48h-EC100 was determined to be 9.4 (nominal 8.8) mg test item/L.

Algal Growth Inhibition

The aquatic toxic potential in this study was determined by the addition of humic acid. Humic acid is a principal component in the environment, it is formed by biodegradation of dead organic matter. Therefore it simulates natural conditions much more realistic than without the addition of humic acid.

A study according to OECD guideline 201, EC Regulation C.3 and OPPTS 850.5400 was conducted to determine the aquatic toxic potential of the test item on the growth of a unicellular green algal species Pseudokirchneriella subcapitata by addition of humic acid. Humic acid is formed by biodegradation of dead organic matter. It is a principal component in the environment, for example in lakes and in the soil. Exponentially growing cultures of Pseudokirchneriella subcapitata were exposed to various concentrations of the test item over several generations under defined conditions. The algal growth in relation to a control culture was determined over a fixed test period of 72 hours and thus, over several algal generations. The test method of application and the test species Pseudokirchneriella subcapitata are recommended by the test guidelines. Based on the results of non-GLP Preliminary Range-Finding Test the following five test concentrations in a geometric series (with a separation factor of 2.0) were tested: 0.6, 1.3, 2.5, 5.0 and 10.0 mg/L (nominal). Each test group contained dissolved humic acid in 10 mg/L nominal concentration. Untreated- and humic acid-control (10 mg/L) ran parallel in the test. The analytically measured concentrations deviated more than 20 % from the nominal during the experiment therefore the geometric mean of the measured concentrations were calculated in order to determine exposure concentrations. The corresponding calculated geometric mean concentrations were the followings: 0.40, 0.85, 2.07, 4.55 and 7.15 mg/L. All biological results are based on the measured geometric mean test item concentrations. For the determination of the LOEC and NOEC, the calculated mean growth rates and yield at the test concentrations were tested on significant differences to the control values by Bonferroni t-Test using TOXSTAT software. The test item had a statistically significant inhibitory effect on the growth of Pseudokirchneriella subcapitata after the exposure period of 72 hours based on the average specific growth rate and yield in the two highest test concentrations of 4.55 and 7.15 mg/L (Bonferroni t-Test, 1 tailed, α=0.05) when compared to the humic acid-control. Accordingly, the 72-hour NOEC related to growth rate and yield was determined to be 2.07 mg/L. The EC values of the test item and their confidence limits were calculated using Probit analysis by TOXSTAT software. The 72-h EyC10 based on yield was determined to be 1.40 mg/L and the 72-h EyC50 as 2.50 mg/L. The 72 hour ErC10 was determined to be 1.99 mg/L and ErC50 value was determined to be 3.13 mg/L.

Activated Sludge

In comparison to the inoculum controls the respiration rate of the activated sludge was inhibited between 4.4 % and 96.5 % in the examined nominal test concentration range. The inhibition showed a nearly dose-related tendency. The respiration rate was inhibited with 96.5 % at the concentration level of 313 mg/L and 92.9 % at the highest concentration level, at 1000 mg/L. Concentrations exceeding 1000 mg/L nominal were not tested. The NOEC was determined to be 31 mg/L and the EC50 was determined to be 72.6 mg/L.