4,5-dichloro-2-nitroaniline

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:

Data is from OECD QSAR toolbox version.3.3 and QMRF report has been attached.

Qualifier:

according to guideline

Guideline:

other: Predicted data

Principles of method if other than guideline:

Prediction is done using QSAR Toolbox version 3.3 with log kow as the primary discriptors.

GLP compliance:

no

Specific details on test material used for the study:

Name ( IUPAC):4,5-Dichloro-2-nitroaniline
Molecular formula:C6H4Cl2N2O2
Molecular weight: 207.016 g/mol
Smilies:Nc1cc(Cl)c(Cl)cc1[N+]([O-])=O
Inchi:1S/C6H4Cl2N2O2/c7-3-1-5(9)6(10(11)12)2-4(3)8/h1-2H,9H2
Substance type: Organic
Physical state: solid

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.3 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: toxic

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" or "e" or "f" )  and "g" )  and ("h" and ( not "i") )  )  and ("j" and ( not "k") )  )  and ("l" and ( not "m") )  )  and ("n" and "o" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Strong binder, NH2 group by Estrogen Receptor Binding

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SNAr OR SNAr >> Nucleophilic aromatic substitution OR SNAr >> Nucleophilic aromatic substitution >> Activated halo-benzenes by Protein binding by OECD ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as SNAr OR SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds OR SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds >> Activated aryl and heteroaryl compounds by Protein binding by OASIS v1.3 ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroaniline Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroarenes with Other Active Groups OR SN1 OR SN1 >> Nucleophilic attack after diazonium or carbenium ion formation OR SN1 >> Nucleophilic attack after diazonium or carbenium ion formation >> Nitroarenes with Other Active Groups OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitroaniline Derivatives OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitroarenes with Other Active Groups OR SN2 OR SN2 >> SN2 attack on activated carbon Csp3 or Csp2 OR SN2 >> SN2 attack on activated carbon Csp3 or Csp2 >> Nitroarenes with Other Active Groups by DNA binding by OASIS v.1.3 ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as SN1 OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Aromatic nitro OR SN1 >> Nitrenium Ion formation >> Primary aromatic amine by DNA binding by OECD ONLY

Domain logical expression index: "g"

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

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as No alert found by Protein binding alerts for Chromosomal aberration by OASIS v1.1

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Michael addition to the quinoid type structures OR AN2 >> Michael addition to the quinoid type structures >> Substituted Anilines by Protein binding alerts for Chromosomal aberration by OASIS v1.1

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as No alert found by Respiratory sensitisation

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Pro-Michael Addition OR Pro-Michael Addition >> Pro-quinone and related OR Pro-Michael Addition >> Pro-quinone and related >> Phenylenediamines by Respiratory sensitisation

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Anilines (Unhindered) by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "m"

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

Domain logical expression index: "n"

Parametric boundary:The target chemical should have a value of log Kow which is >= 1.36

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of log Kow which is <= 4.23

Conclusions:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity on aquatic algae predicted for 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1). Effect concentration i.e EC50 value estimated to be 5.3 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1) is likely to be toxic to aquatic algae, hence it can be considered to be “aquatic chronic 2" as per the CLP classification criteria for aquatic environment.

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity on aquatic algae predicted for 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1). Effect concentration i.e EC50 value estimated to be 5.3 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1) is likely to be toxic to aquatic algae, hence it can be considered to be“aquatic chronic 2" as per the CLP classification criteria for aquatic environment.

Description of key information

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity on aquatic algae predicted for 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1). Effect concentration i.e EC50 value estimated to be 5.3 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1) is likely to be toxic to aquatic algae, hence it can be considered to be“aquatic chronic 2" as per the CLP classification criteria for aquatic environment.

Key value for chemical safety assessment

EC50 for freshwater algae:

5.3 mg/L

Additional information

Following studies include the predicted data and experimental study for the target chemical and structurally similar read across to conclude the toxicity extent of 4,5-Dichloro-2-nitroaniline(CAS: 6641-64-1)) towards aquatic algae is summarized as follows:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity on aquatic algae predicted for 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1). Effect concentration i.e EC50 value estimated to be 5.3 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1) is likely to be toxic to aquatic algae, hence it can be considered to be“aquatic chronic 2" as per the CLP classification criteria for aquatic environment.

Similar predicted data for the target chemical indicates tahte the On the basis of EPI suite, ECOSAR version 1.1, the LC50 value for short term toxicity to aquatic algae was predicted to be 1.15 mg/l for 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1) in 96 hrs. Based on the LC50 value, it can be concluded that the substance 4,5-Dichloro-2-nitroaniline (CAS: 6641-64-1) can be considered as toxic to aquatic environment and hence can be considered to be “aquatic chronic 2" as per the CLP classification criteria for aquatic environment.

The above predicted data of target cheimcal is supported by the experimental studystructurally similar read across2,4,5-trichloroaniline (CAS: 636-30-6) from the publication Aquatic Toxicology 1999, suggests that the Effects on the population growth inhibition of algae was tested according to the OECD guidelines for 2,4,5-trichloroaniline under static condition. The Effective concentration EC50 to 50% ofChlorella pyrenoidosa at 72 hr is 3 mg/l. It can be concluded from the value that the 2,4,5-trichloroaniline is not toxic to the aquatic algae and can be considered as “aquatic chronic 2” as per classification criteria for aquatic invertebrate.

Further it is supported bythe experimental study another structurally similar read across 2,4-xylidine(CAS: 95 -68 -1), from the publication Water Research 1980 indicates that the cell multiplication inhibition test was carried out for 72 hrs to study the effects of 2,4-xylidine on aquatic algae.

The lowest-observed-effect concentration (LOEC) to Scenedesmus quadricauda in 72 hrs is 9.8 mg/l. cell multiplication inhibition was measured during the test. It can be concluded that the 2,4-xylidine is toxic to the aquatic environment and hence from the value it can be considered as “aquatic chronic 2” as per the CLP classification criteria.

Thus based on the effect concentrations which is in the range 1.15 mg/l to 9.8 mg/l give the conclusion that test substance4,5-Dichloro-2-nitroaniline(CAS: 6641-64-1)is likely to be toxic to aquatic algae at environmentally relevant concentrations and applying weight of evidence approach it can be considered to be “aquatic chronic 2" as per CLP classification criteria for aquatic environment.