Styrax benzoin, ext.

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction from an well known and acknowledged tool. See below under 'Overall remarks, attachments' for applicability domain and 'attached background material section' for methodology.

Qualifier:

according to guideline

Guideline:

other: REACH guidance on QSARs: Chapter R.6. QSARs and grouping of chemicals

Principles of method if other than guideline:

Since the test substance is an UVCB, the short-term toxicity to daphnids were predicted for three major constituents (cinnamic acid, p-coumaryl cinnamate and conferyl cinnamate), which corresponds to more than 90% of the composition, followed by the selection lowest value for hazard assessment.

GLP compliance:

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

ca. 1.16 - ca. 2.56 mg/L

Nominal / measured:

estimated

Conc. based on:

other: p-coumaryl cinnamate

Basis for effect:

mobility

Remarks on result:

other: based on LC50 value predictions for three classes (i.e., esters, phenol and vinyl/allyl/propargyl ester) identified in p-coumaryl cinnamate

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

ca. 601 mg/L

Nominal / measured:

estimated

Conc. based on:

other: cinnamic acid

Basis for effect:

mobility

Remarks on result:

other: LC50 prediction for neutral organic class identified in cinnamic acid

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

ca. 1.56 - ca. 3.66 mg/L

Nominal / measured:

estimated

Conc. based on:

other: coniferyl cinnamate

Basis for effect:

mobility

Remarks on result:

other: based on LC50 value predictions for three classes (i.e., esters, phenol and vinyl/allyl/propargyl ester) identified in coniferyl cinnamate

Details on results:

Refer to the details under 'Any other information on results incl. tables sections'.

Results

ECOSAR - Daphnia
Name	SMILES	Endpoint	Category if any	LC50 (mg/L)	Log Kow	Log Kow cut off	Water solubility (mg/L)	Molecular weight	Domain evaluation
p-Coumaryl cinnamate	Oc1ccc(C=CCOC(=O)C=Cc2ccccc2)cc1	Short term toxicity to aquatic invertebrate: Daphnia (ECOSARv2.0)	Esters	2.56	4.35	5	11.65	280.33	ID - Log Kow, MW, Water Sol
			Phenol	1.16	4.35	7	11.65	280.33	ID - Log Kow, MW, Water Sol
			Vinyl/Allyl/Propargyl ester	2.2	4.35	5	11.65	280.33	ID - Log Kow, MW, Water Sol
Cinnamic acid	C1=CC=C(C=C1)C=CC(=O)O	Short term toxicity to aquatic invertebrate: Daphnia (ECOSARv2.0)	Neutral organics	601.01	2.07	5	570	148.16	ID - Log Kow, MW, OD - Water Sol
Coniferyl cinnamate	COc1cc(C=CCOC(=O)C=Cc2ccccc2)ccc1O	Short term toxicity to aquatic invertebrate: Daphnia (ECOSARv2.0)	Esters	3.66	4.18	5	2.89	310.35	ID - Log Kow, MW, OD - Water Sol
			Phenol	1.56	4.18	7	2.89	310.35	ID - Log Kow, MW, Water Sol
			Vinyl/Allyl/Propargyl ester	2.71	4.18	5	2.89	310.35	ID - Log Kow, MW, Water Sol

For more details on the results, kindly refer the attached background material section of the IUCLID.

Validity criteria fulfilled:

not applicable

Conclusions:

The daphnid 48-h LC50 values for the major constituents were predicted to range between 1.16 to 601 mg/L and the lowest value of 1.16 mg/L has been taken forward for hazard/risk assessment.

Executive summary:

The short-term toxicity to aquatic invertebrates of the test substance was predicted using the ECOSAR v2.0 QSAR model of US EPA. Since the test substance is a UVCB, the daphnid 48-h LC50 values were predicted for the three major constituents (cinnamic acid, p-coumaryl cinnamate and coniferyl cinnamate), which correspond to more than 90% of the composition. SMILES codes were used as input parameter. The predicted daphnid 48-h LC50 values for the modelled constituents ranged from 1.16 to 601.01 mg/L (US EPA, 2019). Applicability domain evaluation was performed by checking against the maximum limits of the dependent molecular descriptors of the model (i.e., log Kow, molecular weight (MW) and water solubility). The predictions for all identified classes of the three constituents were below the maximum limits for log Kow and MW. With respect to WS, the values of cinnamic acid and coniferyl cinnamate exceeded the predicted maximum water solubility limits for the ester category, indicating there is the possibility of some effects at saturation. Therefore, the short-term toxicity to daphnia predictions for the major constituents are considered to be reliable with restrictions and the lowest LC50 value has been considered for hazard/risk assessment as a conservative approach.

Description of key information

The daphnid 48-h LC50 values for the major constituents were predicted to range between 1.16 to 601 mg/L and the lowest value of 1.16 mg/L has been taken forward for hazard/risk assessment.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.16 mg/L

Additional information

The short-term toxicity to aquatic invertebrates of the test substance was predicted using the ECOSAR v2.0 QSAR model of US EPA. Since the test substance is a UVCB, the daphnid 48-h LC50 values were predicted for the three major constituents (cinnamic acid, p-coumaryl cinnamate and coniferyl cinnamate), which correspond to more than 90% of the composition. SMILES codes were used as input parameter. The predicted daphnid 48-h LC50 values for the modelled constituents ranged from 1.16 to 601.01 mg/L (US EPA, 2019). Applicability domain evaluation was performed by checking against the maximum limits of the dependent molecular descriptors of the model (i.e., log Kow, molecular weight (MW) and water solubility). The predictions for all identified classes of the three constituents were below the maximum limits for log Kow and MW. With respect to WS, the values of cinnamic acid and coniferyl cinnamate exceeded the predicted maximum water solubility limits for the ester category, indicating there is the possibility of some effects at saturation. Therefore, the short-term toxicity to daphnia predictions for the major constituents are considered to be reliable with restrictions and the lowest LC50 value has been considered for hazard/risk assessment as a conservative approach.