Hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

Endpoint summary

Additional information

Based on the available data on short term toxicity to several different species (fish, daphnia, algae and microorganisms), the test substance is not regarded as toxic to the aquatic environment. According to the long-term toxicity result of a structurally related compound the substance is not chronically toxic to aquatic species either.

Short-term toxicity to fish

In a 96-hour acute toxicity study, zebra fish were exposed to the test substance at nominal concentrations of 0 (control, vehicle control) and 100 mg/L under static conditions. The 96-hour LC50 was above 100 mg/L. No mortality or any sublethal effects were observed in control, vehicle control and dosing groups. Swimming behavior, loss of equilibrium, respiratory function, exophtalmus and pigmentation were normal throughout the study period.

Short-term toxicity to Daphnia

The 24-hour acute toxicity of the test substance to Daphnia magna STRAUS was studied under static conditions. Daphnids were exposed to control, vehicle control and test chemical at nominal concentrations of 10, 18, 32, 58, and 100 mg/L for 24 hours at 20 °C. Immobilisation and sublethal effects were observed at test termination. 20 daphnids were tested per control or concentration level, i.e. 4 replicates of 5 daphnia each.

No immobilised daphnids were observed at any of the concentrations tested. The 24-hour EC50 was above 100 mg/L.

Long-term toxicity to Daphnia (data derived from the read across compound CAS 41484-35-9)

The 21d chronic toxicity of the read across compound CAS 41484-35-9 was assessed in a limit test with nominal 10 mg/L test compound under semi-static, daily renewal conditions in accordance with the OECD 211 guideline. No significant mortality or any other additional significant adverse effects or abnormal behavior were observed in any of the test treatments. The NOEC was determined to be ≥ 10 mg/L.

Toxicity to aquatic algae and cyanobacteria

In a 72-h acute toxicity study, freshwater green algae (Scenedesmus subspicatus) were exposed to the test substance at nominal concentrations of 0 (blank and vehicle control), 1.23, 3.7, 11, 33 and 100 mg/L under static conditions according to EU method C.3 (BASF, 1992). Each test concentration was tested in 3 replicates, the blank control in 6 replicates. The 72-h NOEC and EC50 based on biomass were 33 mg/L and above 100 mg/L, respectively. The % growth inhibition in the treated culture as compared to the control ranged from 0 to 42.9 % at the highest tested concentration. There were no compound related phytotoxic effects during the entire study period.

Toxicity to microorganisms

The inhibitory effects of the test substance on the respiration rate of aerobic waste water bacteria was examined in a static test according to OECD guideline 209 (BASF, 1998). Bacteria were cultivated under specific conditions and respiration rate was determined under the influence of test substance compared to blank and positive controls. Therefore the oxygen consumption of the bacteria suspension was measured after the incubation period with the test substance. As positive control substance 3,5-Dichlorophenol was used in concentrations of 3.2, 10 and 32 mg/L. An IC50 of 14 mg/L was determined for the positive control.

The bacteria were incubated in duplicate with the test substance at the dose level of 100 mg/L (nominal concentration) for 3 hours. The following inhibitory concentrations were determined:

IC20 (3h) > 100 mg/L

IC50 (3h) > 100 mg/L

IC80 (3h) > 100 mg/L