Hexa-1,5-diene

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

23 May 2018

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 adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
EpiSuite (version 4.11)

2. MODEL
ECOSAR (version 1.11)

3. CHEMICAL NAME: 1,5-Hexadiene
CAS#: 592-42-7
SMILES: C(=C)CCC=C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The ECOSAR QSAR is a well-established and widely used model that is integrated in the EpiSuite software and is known to be accepted by the European Chemicals Agency (ECHA). As such, the QSAR model is considered to be scientifically valid.

5. APPLICABILITY DOMAIN
The substance adequately falls within the applicability domain of the model.

6. ADEQUACY OF THE RESULT
The predicted result is considered to be adequate for the purpose of classification and labelling and/or risk assessment.

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

Mayo-Bean, K. 2012. The ECOSAR (ECOlogical Structure Activity Relationship) Class program for Microsoft Windows. U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, MC 7101M, 1200 Pennsylvania Avenue, N.W., Washington, DC 20460.

Specific details on test material used for the study:

SMILES: C(=C)CCC=C

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

6.87 mg/L

Basis for effect:

mortality

Remarks on result:

other: QSAR predicted value

ECOSAR (version 1.11) predicted that Hexa-1,5-diene has an acute 48 hour LC50 value of 6.87 mg/L to Daphnia.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

5 May 2018

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 adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
QSAR Toolbox

2. MODEL
QSAR Toolbox (version 4.1)

3. CHEMICAL NAMES: 1,5-Hexadiene;
Hexa-1,5-diene
CAS#: 592-42-7
SMILES: C=CCCC=C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The OECD Toolbox is a well-established and widely used model that is endorsed and accepted by the European Chemicals Agency (ECHA). As such, the QSAR model is considered to be scientifically valid.

5. APPLICABILITY DOMAIN
The substance adequately falls within the applicability domain of the model.

6. ADEQUACY OF THE RESULT
The predicted results are considered to be adequate for the purpose of classification and labelling and/or risk assessment.

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

OECD. 2017. QSAR Toolbox (version 4.1). Laboratory of Mathematical Chemistry. ul. "Professor Yakim Yakimov" 1, 8010 VHTI Professor Dr. Asen Zlatarov, Burgas, Bulgaria.

Specific details on test material used for the study:

SMILES: C=CCCC=C

Test organisms (species):

Daphnia magna

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.66 mg/L

Basis for effect:

mobility

Remarks on result:

other: QSAR predicted value

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

42.5 mg/L

Basis for effect:

other: Intoxication

Remarks on result:

other: QSAR predicted value

The QSAR Toolbox predicted Hexa-1,5-diene acute toxicity to Daphnia magna 48 hour EC50 values of 2.66 mg/L based on immobilisation and 42.5 mg/L based on intoxication.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The substance, Hexa-1,5-diene is known to be highly volatile, with an experimental vapour pressure of 29500 Pa (at 25°C) having been reported in the EpiSuite (version 4.11) experimental database. Given the very high volatility of the substance, it is concluded that testing is not technically feasible and as such the ecotoxicity of the substance has instead been predicted via QSAR models.

Description of key information

The substance, Hexa-1,5-diene is known to be highly volatile, with an experimental vapour pressure of 29500 Pa (at 25°C) having been reported in the EpiSuite (version 4.11) experimental database. Given the very high volatility of the substance, it is concluded that testing is not technically feasible and as such the ecotoxicity of the substance has instead been predicted via QSAR models.

The short-term toxicity of Hexa-1,5-diene to the aquatic invertebrate, Daphnia magna, has been predicted via the QSAR Toolbox (version 4.1) and the ECOSAR (version 1.11) QSAR within the EpiSuite software (version 4.11). Both QSAR models fulfil the OECD principles for QSAR model validation and the substance adequately falls within the applicability domain of the models. As such, the prediction results are considered adequate for addressing the short-term toxicity to aquatic invertebrates data requirement.

 

The following QSAR predictions were derived:

-         OECD Toolbox: 48 h EC50 (immobilisation) = 2.66 mg/L

-         OECD Toolbox: 48 h EC50 (intoxication) = 42.5 mg/L

-         ECOSAR (version 1.11): 48 h LC50 = 6.87 mg/L

 

The most conservative predicted acute toxicity value of Hexa-1,5 -diene to D. magna was a 48 h EC50 of 2.66 mg/L (via the OECD Toolbox) and has therefore been assigned as the key value for chemical safety assessment for this data requirement.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.66 mg/L