Phenethyl propionate

Endpoint summary

Description of key information

Short-term toxicity to fish

2-phenylethyl propanoate is a popular insect attractant. It was evaluated for toxicity to fish in static fish toxicity assay.

For tests of toxicity to fish, bioassay vessels were lined with disposable polyethylene bags and filled with 12.5 liter reconstituted water (30 mg CaSO4, 30 mg MgSO4, 48 mg NaHCO3,and 2 mg KCl added per liter of deionized water). Ten fish were placed in each vessel and allowed 24 hr to become acclimated. Calculated amounts of each test material, as 1 or 10% (w/v) solutions in acetone, were then added to the bioassay vessels. Each material was tested at five concentrations, selected on the basis of preliminary screening tests to determine the approximate ranges of toxicity. Control groups of fish in untreated water and in water to which acetone only was added were observed concurrently. The fish were observed for 96 hr and all deaths and/or untoward behavioral reactions were recorded. The concentration of dissolved oxygen was measured in all solutions in which deaths occurred to be sure the test water contained sufficient oxygen; dissolved oxygen concentrations above 4 mg/liter (.4 ppm for the warm-water fish (bluegills) considered adequate.

The median lethal concentrations (LC50) of the test materials were calculated whenever the data permitted (Litchfield and Wilcoxon. 1949).To check on suitability as test subjects. Fish from each lot were challenged, under the same experimental conditions, with a reference pesticide (toxaphene, at 0.010, 0.018, and 0.056 ppm). The observed 96-hr LC50 was usually around 0.02 ppm; with one lot of bluegills there were no deaths at 0.018 ppm and no survivors at 0.056 ppm.

With higher doses of 2-phenylethyl propanoate to bluegills became quiescent and flaccid, swimming or lying on their sides, with slow respiration.

From experimental result the LC50 for Lepomis macrochirus (Bluegill) was observed to be 12 mg/l after 96 hours of exposure to 2-phenylethyl propanoate.This LC50 value indicate that the test chemical 2-phenylethyl propanoate (Cas no.122 -70 -3) was toxic to fish since chemical is readily biodegradable in water compartment it is considered that the test chemical 2-phenylethyl propanoate is likely to be non-hazardous to fish for acute period of exposure.

Short-term toxicity to aquatic invertebrates

In peer reviewed journalPakistan J. Zool., vol. 39(5), pp. 339-344, 2007 the naturally occurring compounds including target chemical 2-phenylethyl propanoate have been tested for molluscicidal activity against the fresh water snail, Biomphalaria alexandrina.The recommended World Health Organization bioassay procedure (WHO, 1965), was used for the evaluation of 2-phenylethyl propanoate on B. alexandrina.

For experimentBiomphalaria alexandrina species8mm ± 2mm diameter were collected from fresh water ponds at Kafr El-Dwar, Behera Governorate, Egypt and were maintained in glass aquaria oxygenated for one hour daily, one week before testing. The tests were performed in 150 ml glass beakers with ten adult healthy snails per assay. Each chemical was mixed with Tween 20, to ensure complete solubility of the chemical in water. The mixture was added to the glass beaker filled up to 100 ml of the dechlorinated water to give the desired concentration (w/v) up to 400 μg/ml for chemical.

The snails were exposed for 24 h to different concentrations of compounds or their mixture with PB and then transferred to dechlorinated water for another 48 h. Percentage kill were recorded after 72 h.

Percentage mortality was corrected using Abbott's formula (Abbott, 1925). Toxicity parameters for each treatment were computed according to the probit-analysis method by Finney (1971).

According to experimental result the lethal concentration (LC50) value of phenethyl propionate in aquatic invertebrate [Biomphalaria alexandrina ] in a 72 hr study on the basis of mortality effect was found to be 296.27 mg/L.

Toxicity to aquatic algae and cyanobacteria

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 2-phenylethyl propanoate. EC50 value was estimated to be 109.86 mg/l for Pseudokirchneriella subcapitata for 72 h duration. This effect value indicating that the substance 2-phenylethyl propanoate (CAS no. 122-70-3) does not pose a significant hazard to algae and thus consider to be not classifies as per the CLP classification criteria.

Additional information

Short-term toxicity to fish

Three studies from experimental study from peer reviewed journal and predicted data from validated model for short term fish toxicity endpoint for test chemical 2-phenylethyl propanoate (Cas no. 122-70-3) were reviewed as follows:

First study from peer reviewed journal TOXICOLOGY AND APPLIED PHARMACOLOGY 31,421-429 (1975) for target indicate For tests of toxicity to fish, bioassay vessels were lined with disposable polyethylene bags and filled with 12.5 liter reconstituted water (30 mg CaSO4, 30 mg MgSO4, 48 mg NaHCO3,and 2 mg KCl added per liter of deionized water). Ten fish were placed in each vessel and allowed 24 hr to become acclimated. Calculated amounts of each test material, as 1 or 10% (w/v) solutions in acetone, were then added to the bioassay vessels. Each material was tested at five concentrations, selected on the basis of preliminary screening tests to determine the approximate ranges of toxicity. Control groups of fish in untreated water and in water to which acetone only was added were observed concurrently. The fish were observed for 96 hr and all deaths and/or untoward behavioral reactions were recorded. The concentration of dissolved oxygen was measured in all solutions in which deaths occurred to be sure the test water contained sufficient oxygen; dissolved oxygen concentrations above 4 mg/liter (.4 ppm for the warm-water fish (bluegills) considered adequate. The median lethal concentrations (LC50) of the test materials were calculated whenever the data permitted (Litchfield and Wilcoxon. 1949).To check on suitability as test subjects. Fish from each lot were challenged, under the same experimental conditions, with a reference pesticide (toxaphene, at 0.010, 0.018, and 0.056 ppm). The observed 96-hr LC50 was usually around 0.02 ppm; with one lot of bluegills there were no deaths at 0.018 ppm and no survivors at 0.056 ppm. With higher doses of 2-phenylethyl propanoate to bluegills became quiescent and flaccid, swimming or lying on their sides, with slow respiration. From experimental result the LC50 for Lepomis macrochirus (Bluegill) was observed to be 12mg/l after 96 hours of exposure to 2-phenylethyl propanoate.

From the same journal i.e TOXICOLOGY AND APPLIED PHARMACOLOGY 31,421-429 (1975) with identical study design for target, the LC50 for Rainbow trout was observed to be >10 - <13 mg/l after 96 hours of exposure to 2-phenylethyl propanoate.

Above both experimental results assist by prediction done using the EPI Suite ECOSAR version 1.10 the 96 hours the lethal concentration LC50 was estimated to be 16.249 mg/l on Fish for target chemical 2-phenylethyl propanoate (Cas no. 122-70-3) on the basis of mortality effects.

All studies for target indicate that the chemical is likely to be toxic to fish with lethal concentration range >10 - 16.249 mg/l but chemical is readily biodegradable in water compartment therefore considered that the test chemical 2-phenylethyl propanoate is likely to be non-hazardous to fish for acute period of exposure as per the CLP criteria of classification.

Short-term toxicity to aquatic invertebrates

Short term toxicity to aquatic invertebrates for 2-phenylethyl propanoate (Cas no. 122-70-3) was summaries with peer reviewed experimental study and predicted data with one read across substance are summaries as follows:

First study from peer reviewed journal Pakistan journal of zoology .39(5): 339-344 for target suggest the naturally occurring compounds including target chemical 2-phenylethyl propanoate have been tested for molluscicidal activity against the fresh water snail, Biomphalaria alexandrina.The recommended World Health Organization bioassay procedure (WHO, 1965), was used for the evaluation of 2-phenylethyl propanoate on B. alexandrina. For experiment Biomphalaria alexandrina species8mm ± 2mm diameter were collected from fresh water ponds at Kafr El-Dwar, Behera Governorate, Egypt and were maintained in glass aquaria oxygenated for one hour daily, one week before testing. The tests were performed in 150 ml glass beakers with ten adult healthy snails per assay. Each chemical was mixed with Tween 20, to ensure complete solubility of the chemical in water. The mixture was added to the glass beaker filled up to 100 ml of the dechlorinated water to give the desired concentration (w/v) up to 400 μg/ml for chemical. The snails were exposed for 24 h to different concentrations of compounds or their mixture with PB and then transferred to dechlorinated water for another 48 h. Percentage kill were recorded after 72 h. Percentage mortality was corrected using Abbott's formula (Abbott, 1925). Toxicity parameters for each treatment were computed according to the probit-analysis method by Finney (1971). According to experimental result the lethal concentration (LC50) value of phenethyl propionate in aquatic invertebrate [Biomphalaria alexandrina ] in a 72 hr study on the basis of mortality effect was found to be 296.27 mg/L.

Above experimental result assist by prediction using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances. By OECD QSAR tool the short term toxicity on aquatic invertebrates was predicted for 2-phenylethyl propanoate (Cas no. 122-70-3) and EC50 value was estimated to be 112.66 mg/l for Daphnia magna for 48 hrs duration.

Both results for target assist by experimental study of read across Benzyl butyrate (Cas no. 103-37-7) (Abitec laboratory result, 2016) which indicate Short term toxicity to aquatic invertebrates was performed in Daphnia magna following the OECD guideline 202. The test was performed for 48 hrs at different concentrations as control,0,2.5,5.0,10.0,20.0,40.0 mg/l at 95 % confidence limit of 14.7 -18.7mg/l.Reference substance used was K2Cr207. 5 daphnids after breeding were used in 4 numbers of replicates of chemical.The test was performed in temperature 20°C±1°C with taking 25ml per replicate in 50ml glass vessel for 48 hrs. Calulations of EC50 was calculated using nonlinear regression by the software Prism4.0 (GraphPadSoftware,Inc.,SanDiegoCA). After experiment the EC50 value for short term toxicity to aquatic invertebrates using OECD guideline 202 was determined to be 16.6 mg/l. Based on the value the benzyl butyrate was toxic to aquatic invertebrates but as the chemical was readily biodegradable, so it can be considered that benzyl butyrate was not hazardous to aquatic invertebrates and can be considered not classified as per the CLP regulations.

Based on the target and read across chemical studies, it was considered that 2-phenylethyl propanoate (Cas no. 122-70-3) was not hazardous to aquatic invertebrates and can be considered to be not classified as chemical not exceed the aquatic classification criteria of CLP regulation.

Toxicity to aquatic algae and cyanobacteria

Three studies including predicted data from validated tool and experimental data from authorative laboratory report and journal for toxicity to aquatic algae endpoint of test chemical 2-phenylethyl propanoate (Cas no. 122-70-3) with relevant read across which is structurally similar to target were summarised as follows:

 

First data from prediction using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, which indicate the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance chemical 2-phenylethyl propanoate (Cas no. 122-70-3). The EC50 value was estimated to be 109.86 mg/l for Pseudokirchneriella subcapitata for 72 h duration. 

 

And read across Benzyl butyrate (Cas no. 103-37-7) suggest The effect of test item Benzyl butyrate, CAS No. 103-37-7 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga growth inhibition test. The test concentration chosen for the study were 6.25mg/L, 12.5mg/L, 25mg/L, 50 mg/L, 100mg/L and 200mg/L. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be >200mg/L. (Abitech results), 2016)

 

And another read across chemical Benzyl acetate (Cas no. 140-11-4) from peer reviewed journal Food and Chemical Toxicology (2015), Pg. no. 1-10 suggest A 72 h algae inhibition test was conducted according to the OECD Guideline 201 (Alga, Growth Inhibition Test). Based on the effect on growth rate of the test organism, the 72 hrs EC50 value was determined to be 110 mg/l, respectively.

Thus based on the effects from all studies give the conclusion that test substance 2-phenylethyl propanoate (Cas no. 122-70-3) with effect concentrations in the range 109.86 to >200 mg/l was likely to be non toxic to aquatic algae as it not meet the classification criteria of aquatic toxicity as per the CLP regulation.