3,7-dimethylocta-2,6-dienenitrile

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)

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

Prediction is done using QSAR Toolbox version 3.4

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

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

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Hardness:

No data available

Test temperature:

23.1 – 23.5 °C

pH:

7.7 - 9.5

Dissolved oxygen:

No data available

Salinity:

No data available

Nominal and measured concentrations:

No data available

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.174 mg/L

Nominal / measured:

nominal

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: In Domain

((((("a" or "b" or "c" )  and ("d" and ( not "e") )  )  and ("f" and ( not "g") )  )  and "h" )  and ("i" and "j" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Alkene AND Allyl AND Nitrile AND Terpenes by Organic Functional groups

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Nitrile AND Overlapping groups AND Terpenes by Organic Functional groups (nested)

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acetylenic Carbon [#C] AND Aliphatic Carbon [CH] AND Aliphatic Carbon [-CH2-] AND Aliphatic Carbon [-CH3] AND Olefinic carbon [=CH- or =C<] by Organic functional groups (US EPA)

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.4

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation >> Geminal Polyhaloalkane Derivatives OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide and Aminoalkylamine Side Chain OR Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Geminal Polyhaloalkane Derivatives OR SN2 OR SN2 >> Acylation involving a leaving group after metabolic activation OR SN2 >> Acylation involving a leaving group after metabolic activation >> Geminal Polyhaloalkane Derivatives OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Quinoline Derivatives OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation >> Geminal Polyhaloalkane Derivatives OR SN2 >> SN2 at an activated carbon atom OR SN2 >> SN2 at an activated carbon atom >> Quinoline Derivatives by DNA binding by OASIS v.1.4

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Not possible to classify according to these rules (GSH) by Protein binding potency

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Slightly reactive (GSH) OR Slightly reactive (GSH) >> 2-Alkenyl carbonitriles (MA) OR Slightly reactive (GSH) >> Methacrylates (MA) by Protein binding potency

Domain logical expression index: "h"

Similarity boundary:Target: CC(C)=CCCC(C)=CC#N
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "i"

Parametric boundary:The target chemical should have a value of log Kow which is >= 1.26

Domain logical expression index: "j"

Parametric boundary:The target chemical should have a value of log Kow which is <= 3.96

Validity criteria fulfilled:

not specified

Conclusions:

The median Effective concentration (EC50) value for Citralva on Pseudokirchnerella subcapitata in a 72 hour study was estimated to be 3.1739 mg/L on the basis of effects on growth rate.

Executive summary:

72 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound Citralva (CAS no. 5146 -66 -7) and the result were predicted. The study was based on the effects of the test compound on Pseudokirchnerella subcapitata in a static fresh watersystem. The predicted data suggests the effective concentration (EC50) for thetest compound Citralva(CAS no. 5146 -66 -7) was estimated to be 3.1739 mg/l on the basis of growth rate. Ths, based on this value, it can be concluded that the test chemical can be considered as toxic to aquatic organisms and thus can be

classified as aquatic chronic category 2 as per the CLP criteria.

Description of key information

72 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound Citralva (CAS no. 5146 -66 -7) and the result were predicted (SSS QSAR Prediction model, 2016). The study was based on the effects of the test compound on Pseudokirchnerella subcapitata in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound Citralva (CAS no. 5146 -66 -7) was estimated to be 3.1739 mg/l on the basis of growth rate.

Key value for chemical safety assessment

EC50 for freshwater algae:

3.174 mg/L

Additional information

Various predicted data for the target chemicalCitralva(CAS No. 5146-66-7) and the study of its read across substancewere reviewed to summarize the following information:

72 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound Citralva (CAS no. 5146 -66 -7) and the result were predicted (SSS QSAR Prediction model, 2016). The study was based on the effects of the test compound on Pseudokirchnerella subcapitata in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound Citralva (CAS no. 5146 -66 -7) was estimated to be 3.1739 mg/l on the basis of growth rate.

 

Based on the QSAR prediction done using the EPI Suite ECOSAR version 1.10 (EPI Suite, 2016), the 96 hours EC50 was estimated to be 5.014 mg/l on green algae for substance Citralva with growth inhibition effects.

The short term toxicity study to algae test was performed according to OECD guideline 201 in closed vessels (CLASSIFICATION AND LABELLING OF DANGEROUS SUBSTANCES Recommended form to be used for the proposed classification and labelling of a dangerous substance under Directive 67/548/EEC, January 2007). The test performed onDesmodesmus subspicatusCHODAT SAG 86.81strain, with dose concentration of 3.7 to 100 mg/L which were weighed separately (differential loading) and exposure duration was 72-h. Due to technical reasons for the concentrations 1.23 mg/l to 0.015 mg/l an eluate was created and used for the study. The 72-h E_bC50 and E_rC50 value was found to be 5.92 and 6.35 respectively when exposed to algae by chemical 3,7-dimethylocta-2,6-dienenitrile.

Short term toxicity toSelenastrum capricornutum (green algae) study was carried out for 96 hrs (Danisco US Inc, 8EHQ-0309-17438A, March 6, 2009). The study was based on the effects of the test compound onSelenastrum capricornutumin a static fresh water system. The 72 hrs IC50 and NOEC values on Selenastrum capricornutum was determined to be 3.99 mg/l and < 1 mg/l, respectively.

Based on the overall reported results for target and read across substance, it can be concluded that the substance Citralva can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 2 as per the CLP criteria.