4-(1,1-dimethylethyl)cyclohexyl acrylate

Endpoint summary

Description of key information

Short-term toxicity to fish:

In an acute toxicity test with Danio rerio, an 96h-LC50 >1.27 mg/L (geometric mean measured concentration) was observed (BASF, 140926BZ/FAZ17034, 2016).

Short-term toxicity to aquatic invertebrates:

In an acute immobilisation test with Daphnia magna (STRAUS) according to OECD guideline 202 an EC50 of 1.03 mg/L based on the geometric mean measured test substance concentration was determined (BASF, 50E0580/09X175, 2015).

Toxicity to aquatic alage and cyanobacteria:

In an alga, growth inhibition test according to OECD guideline 201, an EC50- and EC10-value for inhibition of specific growth rate after 72 h was 0.539 mg/L and 0.414 mg/L (based in time weighted average mean measured concentrations; BASF, 60E0580/09X174, 2015).

Toxicity to microorganisms:

In an activated sludge respiration inhibition test according to OECD guideline 209, EC10- and EC50-values of 490 mg/L (95% CI: 368.6 - 657.5) and >1000 mg/L were determined, respectively (BASF, 08G0580/09G176, 2015).

Additional information

Short-term toxicity to fish:

An acute fish toxicity was conducted with Danio rerio (zebrafish) according to OECD guideline 203 (BASF, 140926BZ/FAZ17034, 2016). This semi-static test was performed as a limit test with a nominal threshold concentration of 2.50 mg/L (loading). The test substance concentration was analytically verified via GC-MS. The measured concentrations in freshly prepared media (0 h) were 60 and 75% of the nominal values. In corresponding 24 h aged test media, the measured concentrations were 34 and 44% of the nominal values. Therefore, all effect values are based on the geometric mean measured concentrations of the test item. The tested threshold concentration of 2.50 mg/L corresponds to the geometric mean measured concentration of 1.27 mg/L. After an exposure period of 96 hours, the limit concentration of this test was found to have no lethal effects on zebrafish. Thus, the LC50 was >1.27 mg/L (based on mean measured concentration).

Short-term toxicity to aquatic invertebrates:

An acute immobilisation test with Daphnia magna (STRAUS) was performed according to OECD guideline 202 (BASF, 50E0580/09X175, 2015). The results of preliminary tests including a solubility test carried out as part of a toxicity test with algae demonstrated, that the analysed concentration of the test item in saturated solutions in concentrations clearly above the limit of solubility in water increased with the loading of test item per litre water. Thus the test item cannot be treated like a monomolecular substance with a specific water solubility and aquatic tests have to be conducted with differential loadings. The loadings were considered for the evaluation of the test results.

The main test was conducted in a closed system (sealed glass flasks) under semi-static conditions and the daphnids were exposed to the test substance loading levels of 0 (control), 1, 3.2, 10, 32 and 100 mg/L over a period of 48 hours. The test concentrations were analytically verified. Since the measured test item concentration did not remain within ±20% of the nominal loadings or the initially measured concentrations, the geometric mean measured concentrations of the test item were determined: 0.270, 0.768, 2.52, 2.83 and 4.35 mg/L. After an exposure period of 48 hours an EC50 of 1.03 mg/L (CI: 0.803 - 1.32, nominal EC50: 4.25 mg/L (CI: 3.34 - 5.37)) based on geometric mean measured test item concentrations was determined.

Toxicity to aquatic alage and cyanobacteria:

An algae growth inhibition test with the freshwater green algae Pseudokirchneriella subcapitata was conducted according to OECD guideline 201 (BASF, 60E0580/09X174, 2015). The aim of the study was to assess the effects on the growth rate over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 6153 x 10^3 cells/ mL. The green algae were exposed to the nominal test concentrations of 1, 3.16, 10, 31.6 and 100 mg test item/L, corresponding to the time weighted average mean measured concentrations of 0.428, 1.32, 2.85, 3.49 and 3.89 mg/L.
All test concentrations of the test substance and the control were analytically verified by GC-MS of the two diastereomers after 24 hours and at the end of the exposure. The measured concentrations of the test substance at the start of the exposure were in the range of 3 to 34 % of the nominal test item concentrations. After 24 hours, 4 to 41 % of the nominal test item concentration were found. At the end of the exposure 4 to 55 % of the nominal test item concentration were measured. In all loadings the measured concentration increased during the exposure time. It is assumed that at the beginning of the test the test item was not completely dissolved. After 72 h of exposure (recalculated) EC50 - and EC10 -values for inhibition of specific growth rate of 0.539 mg/L and 0.414 mg/L were determined (based in time weighted average mean measured concentrations).

Toxicity to microorganisms:

An activated Sludge Respiration Inhibition test according to OECD guidelin 209 is available (BASF, 08G0580/09G176, 2015). The test was performed with concentrations of 62.5, 125, 250, 500 and 1000 mg/L as nominal concentration based on test substance without correction of purity and blank controls. After 3 hours incubation time, EC10- and EC50-values of 490 mg/L and >1000 mg/L were determined, respectively.