Phenethyl propionate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

The supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: refer below principle

Principles of method if other than guideline:

The data is predicted using the OECD QSAR toolbox version 3.3 with logKow as the primary descriptor.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): 2-phenylethyl propanoate
- Common name: Phenethyl propionate (PEP)
- Molecular formula: C11H14O2
- Molecular weight: 178.2296 g/mol
- Smiles notation: c1(CCOC(=O)CC)ccccc1
- InChl: 1S/C11H14O2/c1-2-11(12)13-9-8-10-6-4-3-5-7-10/h3-7H,2,8-9H2,1H3
- Substance type: Organic
- Physical state: Liquid

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test temperature:

21 deg C

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

109.86 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

The prediction was based on dataset comprised from the following descriptors: EC50
Estimation method: Takes average value from the 5 nearest neighbours
Domain  logical expression:Result: Out of Domain

(((((((((((((("a" or "b" or "c" )  and "d" )  and "e" )  and "f" )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and "k" )  and "l" )  and "m" )  and "n" )  and "o" )  and ("p" and ( not "q") )  )  and ("r" and ( not "s") )  )  and ("t" and "u" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Esters (Acute toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Esters by Acute aquatic toxicity MOA by OASIS

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as No alert found by Protein binding by OASIS v1.3 ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Class 3 (unspecific reactivity) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Esters by Acute aquatic toxicity MOA by OASIS ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Aliphatic Amines OR Halo Ester OR Surfactants-Nonionic OR Vinyl/Allyl Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as No alert found by rtER Expert System ver.1 - USEPA

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Phthalates by rtER Expert System ver.1 - USEPA

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "l"

Similarity boundary:Target: CCC(=O)OCCc1ccccc1
Threshold=20%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "m"

Similarity boundary:Target: CCC(=O)OCCc1ccccc1
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Aryl AND Carboxylic acid ester by Organic Functional groups ONLY

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Aryl AND Carboxylic acid ester by Organic Functional groups ONLY

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Alkyl substituent on aromatic ring AND Aromatic-CH2 AND Aromatic-H AND Benzene AND -CH2-  [linear] AND Ester   [-C(=O)-O-C] AND Methyl  [-CH3] AND Unsubstituted phenyl group (C6H5-) by Bioaccumulation - metabolism alerts

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as -CH -  [cyclic] by Bioaccumulation - metabolism alerts

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Alkyl substituent on aromatic ring AND Aromatic-CH2 AND Aromatic-H AND Benzene AND -CH2-  [linear] AND Ester   [-C(=O)-O-C] AND Methyl  [-CH3] AND Unsubstituted phenyl group (C6H5-) by Bioaccumulation - metabolism alerts

Domain logical expression index: "s"

Referential boundary: The target chemical should be classified as Unsubstituted phenyl group (C6H5-) by Bioaccumulation - metabolism alerts

Domain logical expression index: "t"

Parametric boundary:The target chemical should have a value of log Kow which is >= 1.57

Domain logical expression index: "u"

Parametric boundary:The target chemical should have a value of log Kow which is <= 3.85

Validity criteria fulfilled:

not specified

Conclusions:

Using OECD QSAR toolbox version 3.3 the median Effective concentration (EC50) value for test chemical 2-phenylethyl propanoate on Pseudokirchneriella subcapitata in a 72 hour study was estimated to be 109.86 mg/L on the basis of effects on growth rate.

Executive summary:

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.

Description of key information

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.

Key value for chemical safety assessment

EC50 for freshwater algae:

109.86 mg/L

Additional information

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.