Isopentyl phenylacetate

Endpoint summary

Description of key information

Short term toxicity to invertebrates:

Aim of this study was to assess the short term toxicity of test chemical to aquatic invertebrates Daphnia magna. Study was performed according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) in a static system for the total exposure period of 48 hrs. The stock solution 20 g/l was prepared in acetone. 0, 0, 1.2, 2.4, 5, 10 and 20 mg/l concentrations were used in the study. Effects on immobilisation were observed for 48 hours. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. The median effective concentration (EC50) of the test substance on Daphnia magna was determined to be 7.71 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, substance consider is likely to be hazardous to aquatic invertebrate and can be classified as aquatic chronic 2 category as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Based on the prediction done using the three different models i.e, Battery, Leadscope and SciQSAR used within Danish QSAR database, the short term toxicity on green algae was predicted for test substance. The average EC50 value was given by the third model i.e, Battery model. On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 11.79 mg/l for Pseudokirchneriella subcapitata during 72 hr exposure duration. Thus, on the basis of EC50 value, it can be concluded that the test chemical can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

Additional information

Short term toxicity to invertebrates:

Various studies available for the test chemical and structurally and functionally similar read across chemical were reviewed to determine the toxic nature of test chemical on the mobility of invertebrates. The studies are as mentioned below:

 

Aim of this study was to assess the short term toxicity of test chemical to aquatic invertebrates Daphnia magna. Study was performed according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) in a static system for the total exposure period of 48 hrs. The stock solution 20 g/l was prepared in acetone. 0, 0, 1.2, 2.4, 5, 10 and 20 mg/l concentrations were used in the study. Effects on immobilisation were observed for 48 hours. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. The median effective concentration (EC50) of the test substance on Daphnia magna was determined to be 7.71 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, substance consider is likely to be hazardous to aquatic invertebrate and can be classified as aquatic chronic 2 category as per the CLP classification criteria.

 

Daphnia sp., Acute Immobilization Test according to OECD Guideline 203 was conducted for test chemical. The test solution was prepared by dissolving 1 g of the test substance in 1 L of ADaM’s media. Kept it for 72 hrs stirring, after stirring stock was analytically detected, the solubility of stock in adams media was determined to be 316.102 mg/L. This stock solution was used for further test concentrations of 6.25 mg/L, 12.5 mg/L, 25 mg/L, 50 mg/L, and 100 mg/L and test Daphnia magna were exposed to these concentration for 48 hours. The median lethal concentration (EC50) for test chemical on Daphnia magna in a 48 hours study on the basis of immobilization effect was observed to be 6.25 mg/l. Test consider to be valid because it meets the criteria as per the OECD guideline. First in the control, including the control containing the solubilising agent, not more that 10 percent of the daphnids should have been immobilized. Secondly the dissolved oxygen concentration at the end of the test should be 3 mg/l in control and test vessels. Thus, on the basis of this EC50 value and according to CLP criteria for aquatic classification of the substance, it is concluded that the substance, does exhibit short term toxicity to Daphnia and consider to be toxic and classified as aquatic chronic 2 as per the CLP classification criteria.

Similar Daphnia sp., Acute Immobilization study according to OECD Guideline 203 was conducted for test chemical. 6.25 mg/L, 12.5 mg/L, 25 mg/L, 50 mg/L, 100 mg/L respectively concentrations were used in the study and test Daphnia magna were exposed to these concentration for 48 hours. The median lethal concentration (EC50) for test chemical on Daphnia magna in a 48 hours study on the basis of immobilization effect was observed to be 6.25 mg/l. Test consider to be valid because it meets the criteria as per the OECD guideline. First in the control, including the control containing the solubilising agent, not more that 10 percent of the daphnids should have been immobilized. Secondly the dissolved oxygen concentration at the end of the test should be 3 mg/l in control and test vessels. Thus, on the basis of this EC50 value and according to CLP criteria for aquatic classification of the substance, it is concluded that the substance, does exhibit short term toxicity to Daphnia and consider to be toxic and classified as aquatic chronic 2 as per the CLP classification criteria.

 

Thus based on the above studies and effects observations on the invertebrate due to the chemical exposure for 48 hours, chemical consider to be toxic and classified in aquatic chronic 2 category as per the CLP classification criteria.

 

 

Toxicity to aquatic algae and cyanobacteria:

Various studies available for the test chemical and structurally and functionally similar read across chemical were reviewed to determine the toxic nature of test chemical on the growth and other behavioral activity of algae and cyanobacteria. The studies are as mentioned below:

 

Based on the prediction done using the three different models i.e, Battery, Leadscope and SciQSAR used within Danish QSAR database, the short term toxicity on green algae was predicted for test substance. The average EC50 value was given by the third model i.e, Battery model. On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 11.79 mg/l for Pseudokirchneriella subcapitata during 72 hr exposure duration. Thus, on the basis of EC50 value, it can be concluded that the test chemical can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Above data further supported by the second study from experimental source. Aim of this study was to evaluate the nature of test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201. The stock solution 100.0 mg/ml was prepared in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. 0, 0, 5, 7, 11, 16.5, 25 mg/l nominal concentration were used. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs. The median effective concentration (EC50) for the test substance, in algae was determined to be 13.4 mg/L with 95% CI: 12.5 -14.4 on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified in chronic 3 category as per the CLP classification criteria.

 

Principle of the third study was to evaluate the nature of test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. 10, 14, 20, 27.4, 38.4 mg/l concentration were used. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs. The median effective concentration (EC50) of the test substance on algae was measured to be 23.6 mg/L with 95% CI: 21.3 -26.1 on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be consider to be classified as aquatic chronic 3 category.

 

Similarly in the fourth weight of evidence study from experimental report, freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance to OECD Guideline 201. Concentration of test chemical used for the study was 0, 6.25, 12.5, 25, 50 and 100 mg/L, respectively prepared in acetone. The test was performed under static conditions at a temp. of 23±2°C. Initial cell density of test organism used was 5x10(3) cells/ml. Determination of cell counting involve the use of microscope with counting chamber Cyrus I or electronic particle counter. ErC50 was calculated using non-linear regression by the software Prism 4.0. The median effective concentration (EC50) for the test substance in Desmodesmus subspicatus was observed to be 34.5 mg/L on the basis of effects on growth rate in a 72 hour study. Thus based on this value, test chemical can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3 as per the CLP criteria.

 

Thus based on the above studies and effects observations on the growth of aquatic algae due to the chemical exposure for 72 hours, chemical consider to be toxic and classified in aquatic chronic 3 category as per the CLP classification criteria.

Based on the overall observations, it is observed that the chemical consider to be higher toxic for fish and invertebrates, whereas less toxic in case on algae. Thus based mobility, mobility inhibition and other effects observation, it is consider that the chemical is toxic and can be consider to be classified in aquatic chronic 2 category, as per the CLP classification criteria.