(E)-1-(2,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one

Endpoint summary

Additional information

Experimental studies and QSAR results are available to assess the aquatic toxicity of the registered substance.

 

To assess the short-term toxicity to fish, one experimental study is available. This study (NOACK, 2015) was performed on the registered substance according to a OECD Guideline 203 in compliance with GLP. In this study, the test substance was exposed to zebra fish Danio rerio at nominal concentrations of 0.342, 0.751, 1.65, 3.64 and 8.00 mg/L, corresponding to geometric mean measured concentrations of 0.263, 0.664, 1.34, 3.47 and 7.30 mg/L, under semi-static conditions for 96 hours, plus one control without test substance. According to the results of this study, the 96h-LC50 was determined at 1.09 mg/L (95% CL: 1.08 -1.10 mg/L), based on geometric mean measured concentrations.

To assess the short-term toxicity to aquatic invertebrate and algae, two reliable QSAR results are available. The QSAR predictions (iSafeRat holistic approach v1.4) has been validated to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004) and predict the ecotoxicological values which would be expected when testing the substance under experimental conditions in a laboratory following OECD Guidelines. The ecotoxicological predictions were determined using a validated QSAR for the Mode of Action in question, (MOA 1, non-polar narcosis). Use of this MOA for substituted α,β-unsaturated ketones has previously been demonstrated as acceptable in a position paper (KREATiS, 2015; available in the Endpoint Study Records). This QSAR is based on validated data for training sets for which the concentrations of the test substance had been determined by chemical analyses over the test period. According to these predictions, the 48h-EC50 value for aquatic invertebrates, based on mobility, was determined to be 9.0 mg/L (95% CL: 8.2 - 9.9 mg/L), and the 72 -h ErC50 value for algae, based on growth rate, was determined to be 8.3 mg/L (95% CL: 7.3 - 9.5 mg/L). The substance falls within the applicability domain of the model.

Finally, to assess the toxicity of the registered substance to microorganisms, one experimental study is available. This study (NOACK, 2015) was performed on the registered substance according to OECD Guideline 209 in compliance with GLP, under static conditions during 3 hours. The mean inhibition of respiration for the test item replicates were -3, 2, 12, 53 and 58% at nominal test substance concentrations of 10, 32, 100, 320 and 1000 mg/L, respectively. Therefore, the test substance is not considered toxic up to the concentration of 32 mg/L to activated sludge of a municipal sewage treatment plant (NOEC value). The 3h-EC10 value was determined at 93.9 mg/L (95% CL: 81.5 -108 mg/L) and the 3h-EC50 value was determined at 275 mg/L (95% CL: 214 -339 mg/L) of the test substance.