2-octadecyl-1H-thioxantheno[2,1,9-def]isoquinoline-1,3(2H)-dione

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:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

Prediction is done using QSAR Toolbox version 3.3

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:

22.6 - 23.0 °C

pH:

7.50 - 8.85

Dissolved oxygen:

No data available

Salinity:

No data available

Nominal and measured concentrations:

No data available

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

20.284 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" or "d" )  and "e" )  and "f" )  and "g" )  and "h" )  and "i" )  and "j" )  and ("k" and "l" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Aryl AND Biphenyl AND Fused carbocyclic aromatic AND Fused saturated heterocycles AND Imide AND Naphtalene AND Quinolone/ Quinolinedione/ Isoquinolinedione AND Sulfide by Organic Functional groups

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Non-covalent interaction AND Non-covalent interaction >> DNA intercalation AND Non-covalent interaction >> DNA intercalation >> Polycyclic Aromatic Hydrocarbon and Naphthalenediimide Derivatives AND SN1 AND SN1 >> Alkylation after metabolically formed carbenium ion species AND SN1 >> Alkylation after metabolically formed carbenium ion species >> Polycyclic Aromatic Hydrocarbon and Naphthalenediimide Derivatives AND SN2 AND SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation AND SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Polycyclic Aromatic Hydrocarbon and Naphthalenediimide Derivatives by DNA binding by OASIS v.1.4

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Iminium Ion Formation AND SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines by DNA binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Direct Acylation Involving a Leaving group AND Acylation >> Direct Acylation Involving a Leaving group >> Acetates by Protein binding by OECD

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Not bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as High (Class III) by Toxic hazard classification by Cramer (original) ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as No superfragment by Superfragments ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 6) ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 5) ONLY

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 2) ONLY

Domain logical expression index: "k"

Parametric boundary:The target chemical should have a value of log Kow which is >= 5.11

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of log Kow which is <= 15.3

Validity criteria fulfilled:

not specified

Conclusions:

The median Effective concentration (EC50) value for 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione on Pseudokirchnerella subcapitata in a 72 hour study was estimated to be 20.2838 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 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline

-1,3(2H)-dione (CAS No. 27870 -92 -4) and the results were predicted. 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 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione (CAS No. 27870 -92 -4) was estimated to be 20.2838 mg/l on the basis of growth rate. . Thus, 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 3 as per the CLP criteria.

Description of key information

72 hrs aquatic toxicity study was predicted (SSS QSAR Prediction model, 2016) to assess toxic effects of the test compound 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione (CAS No. 27870 -92 -4) and the results were predicted. 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 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione (CAS No. 27870 -92 -4) was estimated to be 20.2838 mg/l on the basis of growth rate.

Key value for chemical safety assessment

EC50 for freshwater algae:

20.283 mg/L

Additional information

Various predicted data for the target chemical 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione (CAS No. 27870-92-4) were reviewed to summarize the following information:

72 hrs aquatic toxicity study was predicted (SSS QSAR Prediction model, 2016) to assess toxic effects of the test compound 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione (CAS No. 27870 -92 -4) and the results were predicted. 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 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione (CAS No. 27870 -92 -4) was estimated to be 20.2838 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 0.00000596 mg/l on green algae for substance 2-Octadecyl-1H-thioxantheno(2,1,9-def)isoquinoline-1,3(2H)-dione with growth inhibition effects.

Thus based on above value, it can be concluded that the substance can be considered as toxic to aquatic organisms. Since the substance has a molecular weight of 555.823 g/mol, by speculation, the molecular size of the test substance was so large that reduce the intake rate of chemical into the tissues of aquatic biota. Hence, based on this it can be considered that the chemical was non-toxic to aquatic organisms and thus can be classified as non- hazardous as per the CLP criteria.