1,1'-(4-methyl-1,3-phenylene)bis-1H-pyrrole-2,5-dione

Endpoint summary

Description of key information

- OECD guideline study (203, adopted 1992), 7 Danio rerio for each treatment group, exposure 96h under flow-through conditions, LC50 = 433 µg/L.

- OECD guideline study (202, April 4, 1984), 10 Daphnia magna for treatment group 0.1, 0.22, 0.46, 1.0 and 2.2 mg/L and 20 Daphnids each for the control and the 100 mg/L treatment group, exposure 48h under flow- through conditions, EC50 (24h) = 0.71 mg/L and EC50 (48h) = 0.59 mg/L.

- OECD guideline study (201, adopted 2011), fresh water green alga Desmodesmus subspicatus were exposed to nominal concentrations of 0.625, 1.25, 2.50, 5.00, 10.0 mg/L corresponding to initial measured concentrations of 0.667, 1.33, 2.64, 5.28, 10.6 mg/L for 72h under static conditions. EC50 = > 10.6 mg/L, EC10 = >10.6 mg/L and NOEC (growth) = 2.64 mg/L

- OECD guideline study (209, adopted 2010), Non-adapted activated sludge incubated with 0.1, 0.56, 3.2, 18 and 100 mg/L for 3h, EC50 = 14.9 mg/L; 95 % CI = 13.1-17.1, EC10 = 1.93 mg/L 95 % CI = 1.62 -2.30; NOEC = 0.56 mg/L

Additional information

For the assessment of the aquatic toxicity of 2,4-Bismaleimidotoluene short-term toxicity data with fish, aquatic invertebrates, algae and microorganisms are available.

Short term toxicity to fish

The acute toxicity of the test item 2,4-Bismaleimidotoluene to fish (Danio rerio) was determined according to OECD TG 203 (adopted 1992). Fish were exposed to 1200 µg/L (measured concentration: 782 µg/L) in a first experiment following the threshold approach. Since 3h exposure to the test item at this concentration resulted in 100% mortality a second test was performed with the nominal concentrations of 22.5 - 45.0 - 90.0 - 180 - 360 µg/L (arithmetic mean measured concentrations: 12.7 - 27.0 - 53.4 - 108 - 240 µg/L) for 96h. Both tests were performed using a flow-through test design. Seven test organisms were exposed to each test concentration and the control. In the second definitive test various concentrations of the test item 2,4-Bismaleimidotoluene were analytically verified via LC-MS/MS on study day 0 and daily thereafter until the end of exposure in all tested concentration levels and the control. The measured concentrations of 2,4-Bismaleimidotoluene in the test vessels were in the range of 47 to 77 % of the nominal values during exposure. The measured concentrations of the mixing chamber supplies were in the range of 80 to 92 % at study day 0 and in the range of 81 to 87 % at study day 3 of the nominal values. The LC50 value for the observation time points 3, 24, 48, 72 and 96h was in each case 433 µg/L (arithmetic measured mean). The LC0 was determined to be 240 µg/L.

Short term toxicity to aquatic invertebtates

The 48-hr-acute toxicity of 2,4-Bismaleimidotoluene to Daphnia magna was studied under flow-through conditions according to OECD Guideline 202 (2004). Daphnids were exposed to control and test chemical at nominal concentrations of 0.10, 0.22, 0.46, 1.0 and 2.2 mg a.i./L (corresponding to 0.059, 0.085, 0.19, 0.31 and 0.82 mg/L mean measured concentrations) in Tap water for 48 h.

Mortality/immobilization was observed daily, pH was recorded at the beginning and at the end of the test and temperature was measured continuously. 

The 48-hour EC50 was 0.59 mg a.i./L (95% confidence limits: 0.52 and 0.72 mg/L).

The NOEC was determined to be 0.31 mg/L under flow-through conditions.

Toxicity to aquatic algae and cyanobacteria

In a study conducted according to OECD TG 201 freshwater green alga Desmodesmus subspicatus was exposed to 2,4 -Bismaleimidotoluene at nominal concentrations of 0.625, 1.25, 2.50, 5.00, 10.0 mg/L corresponding to initial measured concentrations of 0.667, 1.33, 2.64, 5.28, 10.6 mg/L for 72h under static conditions.

2,4-Bismaleimidotoluene was found to inhibit the growth rate of the freshwater green alga Desmodesmus subspicatus after 72 hours. The EC50-values with 95 % confidence intervals for both inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 10.6 mg/L, respectively. The EC10-values with 95 % confidence intervals for inhibition of growth rate (ErC10) and yield (EyC10) after 72 hours were > 10.6 mg/L and < 0.667 mg/L, respectively. The NOEC-values for both inhibition of growth rate and yield after 72 hours were 2.64 and < 0.667 mg/L, respectively.

All effect levels are given based on the initially measured test item concentration of 2,4-Bismaleimidotoluene.

Toxicity to microorganisms

The toxicity of 2,4-Bismaleimidotoluene to microorganisms was investigated during an activated sludge respiration inhibition testing according to OECD guideline 209 (2010), respiration inhibition test using an inoculum obtained from non-adapted, activated sludge from a predominantly domestic sewage treatment plant.

Inoculum blank, procedural/functional control with the reference substance Copper (II) sulfate pentahydrate at concentrations of 58, 100 and 180 mg/L reference item and the main test with 0,1, 0.56, 3.2, 18 and 100 mg/L test item 2,4-Bismaleimidotoluene were performed.

The reference toxicity was determined. The EC 50-value for the reference item was 107 mg/L. For the test item the inhibition of respiration was determined. The mean inhibition of respiration for the test item replicates ranged from -2 % to 67 %.

Since, the coefficient of variation of oxygen uptake rates of the control was < 30% and the oxygen uptakes rates of the control replicates were > 20 mg O2/g*h and the EC50-value of the reference was in the range of 53-155 mg/L the validity criteria were fulfilled. The test item had no inhibitory effect on oxygen uptake of sludge microorganisms up to a concentration of 0.56 mg/L, thus, the NOEC of 2,4-Bismaleimidotoluene is 0.56 mg/L. The determined EC50 is 14.9 mg/L (95 % CI = 13.1 -17.1) and the determined EC10 is 1.93 mg/L (95 % CI = 1.62 -2.30).

Conclusion

In the course of aquatic toxicity testing the fish Danio rerio was most sensitive organism to 2,4-Bismaleimidotoluene. The LC50 value determined during a 96h short-term toxicity study under flow-through conditions was 433 µg/L.