Tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate

Endpoint summary

Description of key information

Read-across - Short term toxicity to fish, OECD Guideline 203, Oryzias latipes, semi-static :LC50 (96h) >100 mg/L (nominal)

Read-across - Short term toxicity to aquatic invertebrates, OECD Guideline 202, Daphnia magna, static: EC50 (48h) > 180 mg/L (nominal)

Read-across - Short term toxicity to aquatic algae, OECD Guideline 201, Pseudokirchneriella subcapitata, static: EC50 (72h) > 100 mg/L (nominal), NOEC (72h) = 100 mg/L (nominal)

Toxicity to microorganisms, OECD Guideline 209, Activated sludge: EC50 (3h) > 1000 mg/L (nominal)

Additional information

Read-across - Short-term toxicity to fish

Acute toxicity to fish has been investigated in a 96 hour key study (METI Japan, 1998a) according to OECD Guideline 203 and in compliance to GLP standards with the read-across source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate. The concentration of the test substance in the test medium was increased by generating a supersaturated solution, which was considered to be substantially homogeneous, with the aid of a solubilizer (HCO-40).

The nominal test concentrations of the source test item were 0 and 100 mg/L plus dispersant control in test water for 10 fishes per group, incubated for 96 hours under semi-static conditions.

The LC50 (96h) for Oryzias latipes of the source test item tris(2 -ethylhexyl)benzene-1,2,4 -tricarboxylate was determined to be >100 mg/L (nominal) and can be similarly transferred to the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, due to strong structural analogies.

In a supporting QSAR approach the predicted short-term toxicity effect to fish using ECOSAR model is (96hr) LC50 = 3.19e-6 mg/L. No effects at saturation (NES) are reported.

Read-across - Short-term toxicity to aquatic invertebrates

Acute immobilisation in Daphnia has been investigated in a 48 hour key study (METI Japan, 1998b) according to OECD Guideline 202 and in compliance with GLP criteria with the read-across source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate.The concentration of the test substance in the test medium was increased by generating a supersaturated solution, which was considered to be substantially homogeneous, with the aid of a solubilizer (HCO-40). The nominal test concentrations of the source test item were 0, 17.1, 30.9, 55.6, 100 and 180 mg/L (the 48h-EiC50 for parent Daphnia in an acute immobilization test was > 1000 mg/L) in diluting water in 20 replicates, incubated for 48 hours under static conditions.

The EC50 (48h) for Daphnia magna of the source test item tris(2 -ethylhexyl)benzene-1,2,4 -tricarboxylate was determined to be > 180 mg/L (nominal) and the NOEC was determined to be 180 mg/L, the highest concentration investigated, for the test substance. These results can be similarly transferred to the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, due to strong structural analogies.

Supporting information has been derived using QSAR models. The predicted short-term toxicity effect to aquatic invertebrates using ECOSAR model is (48hr) LC50 = 0.579 mg/L. No effects at saturation (NES) are reported.

The predicted short-term toxicity effect to aquatic invertebrates using DEMETRA model is (48hr) LC50 = 0.0009 mg/L

The substance is not soluble enough to measure this predicted effect. If the effect level exceeds the water solubility by 10X, typically no effects at saturation (NES) are reported. Estimated water solubility: 7.831E-12 (mg/L, EPISuite WSKowwin v1.43 Estimate)

7.03E-7 (mg/L, WATERNT™ by EPI Suite v4.1 estimate). No effects at saturation (NES) are reported.

Read-across - Short-term toxicity to aquatic algae and cyanobacteria

Algal growth inhibition has been investigated in a 72 hour key study (METI Japan, 1998c) according to OECD Guideline 201 and in compliance with GLP criteria with the read-across source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate.

The concentration of the source substance in the test medium was increased by generating a supersaturated solution, which was considered to be substantially homogeneous, with the aid of a solubilizer (HCO-40). The nominal test concentrations of the source test item were 0 and 100 mg/L in OECD medium in triplicate, incubated for 72 hours under static conditions. The EC50 (72h) of Pseudokirchneriella subcapitata of the source test item tris(2 -ethylhexyl)benzene-1,2,4 -tricarboxylate was determined to be >100 mg/L (nominal) and the NOEC (72h) was determined to be 100 mg/L, the highest concentration examined.

These results can be similarly transferred to the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, due to strong structural analogies.

Supporting information has been derived using QSAR model for tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate. The predicted short-term toxicity effect to aquatic algae using ECOSAR model is (96hr) EC50 = 9.45e-8 mg/L. The substance is not soluble enough to measure this predicted effect. No effects at saturation (NES) are reported.

Toxicity to microorganisms

The objective of the key study (Buitenweg, 2018) was to evaluate the test items for its ability to adversely affect aerobic microbial treatment plants and, if possible, to determine the EC50 and/or the no-observed effect concentration (NOEC).The influence of the test item on the respiration rate of activated sludge was investigated after a contact time of 3 hours. The study was performed according to OECD Guideline 209 (2010) in compliance with GLP.

The batch of test item tested was a clear colourless liquid with a purity of 99.8%. No correction was made for the purity/composition of the test item. The test item was not sufficiently soluble to allow preparation of an aqueous solution at a concentration of 10 g/L. Therefore, weighed amounts were added to the test bottles containing Milli-RO water. The test item – Milli-RO water mixtures were magnetically stirred for a short period and subsequently, synthetic medium, sludge and Milli-RO water were added resulting in the required concentrations. Optimal contact between the test item and test medium was ensured by applying continuous aeration and stirring during the 3 hour exposure period. Thereafter, oxygen consumption was recorded for approximately 10 minutes.

In a combined limit/range-finding test concentrations of 10, 100 and 1000 mg/L were tested. The highest concentration was tested in triplicate, lower concentrations consisted of one replicate. Furthermore, at 1000 mg/L an abiotic control (1 replicate) was tested. Responses were compared to the controls.

There was no significant oxygen uptake from abiotic processes.The batch of activated sludge was also tested for sensitivity with the reference item3,5-dichlorophenol, and showed normal sensitivity.

The study met the acceptability criteria prescribed by the study plan and was considered valid. No statistically significant inhibition of the respiration rate of the sludge was recorded at a concentration of 1000 mg/L.Under the conditions of this present test, the test item was not toxic to waste water (activated sludge) bacteria at a concentration of 1000 mg/L (NOEC). The EC50 was above 1000 mg/L.

All these data in supersaturated solution, which was considered to be substantially homogeneous, were obtained with the aid of a solubilizer (HCO-40).

Based on the description of the test results above, it can be concluded that the source substance tris(2 -ethylhexyl)benzene-1,2,4-tricarboxylate does not show any toxic effects at the limit of solubility towards those aquatic organisms, which were tested in the laboratory. These results can be similarly transferred to the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, due to strong structural analogies. Though it is difficult to determine a PNEC, this substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate is not toxic at its water solubility (OECD TG105; < 1.0 mg/L 25°C).