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Toxicity to aquatic algae and cyanobacteria

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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:
The supporting QMRF report has been attached
Qualifier:
according to
Guideline:
other: as mentioned below
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:
not specified
Specific details on test material used for the study:
- Name of test material: 1-(3-aminophenyl)urea
- Molecular formula: C7 H9 N3 O
- Molecular weight: 151.168 g/mol
- Smiles notation: O=C(Nc1cccc(N)c1)N
- InChl: 1S/C7H9N3O/c8-5-2-1-3-6(4-5)10-7(9)11/h1-4H,8H2,(H3,9,10,11)
- Substance type: Organic
- Physical state: Solid
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Test type:
static
Water media type:
freshwater
Total exposure duration:
72 h
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
103.62 mg/L
Nominal / measured:
estimated
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 6 nearest neighbours
Domain  logical expression:Result: In Domain

(((((((("a" or "b" or "c" )  and "d" )  and ("e" and ( not "f") )  )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and "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 Radical AND Radical >> Radical mechanism via ROS formation (indirect) AND Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines AND SN1 AND SN1 >> Nucleophilic attack after metabolic nitrenium ion formation AND SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines by DNA binding by OASIS v.1.3

Domain logical expression index: "c"

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

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Very fast by Bioaccumulation - metabolism half-lives ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Not known precedent reproductive and developmental toxic potential by DART scheme v.1.0

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Inorganic chemical OR Known precedent reproductive and developmental toxic potential OR Metal atoms were identified OR Non-steroid nucleus derived estrogen receptor (ER) and androgen receptor (AR) OR Non-steroid nucleus derived estrogen receptor (ER) and androgen receptor (AR) >> Other non-steroidal estrogen receptor (ER) binding compounds (2b-2) OR Not covered by current version of the decision tree OR Toluene and small alkyl toluene derivatives (8a) by DART scheme v.1.0

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as No alert found by DNA alerts for AMES, MN and CA by OASIS v.1.3

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> Fused-Ring Primary Aromatic Amines OR Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Primary Aromatic Amines OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroaniline Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR SN1 OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Fused-Ring Primary Aromatic Amines OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines 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 >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids by DNA alerts for AMES, MN and CA by OASIS v.1.3

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Not categorized by Repeated dose (HESS)

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as 4,4'-Methylenedianilines/benzidines (Hepatobiliary toxicity) Rank B  OR Allyl esters (Hepatotoxicity) Rank A OR Anilines (Hemolytic anemia with methemoglobinemia) Rank A OR Anilines (Hepatotoxicity) Rank C OR Benzene/ Naphthalene sulfonic acids (Less susceptible) Rank C OR o-/ p-Aminophenols (Hemolytic anemia with methemoglobinemia) Rank B OR p-Aminophenols (Renal toxicity) Rank B by Repeated dose (HESS)

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as H-acceptor-path3-H-acceptor AND Primary aromatic amine, hydroxyl amine and its derived esters by in vivo mutagenicity (Micronucleus) alerts by ISS

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Aromatic diazo by in vivo mutagenicity (Micronucleus) alerts by ISS

Domain logical expression index: "m"

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

Domain logical expression index: "n"

Parametric boundary:The target chemical should have a value of log Kow which is >= -4.13

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of log Kow which is <= 1.81

Validity criteria fulfilled:
not specified
Conclusions:
The short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 1-(3-aminophenyl)urea (25711-72-2). EC50 value was estimated to be 103.62 mg/l for Pseudokirchneriella subcapitata for 72 h duration. Based on the value, the 1-(3-aminophenyl)urea (25711-72-2) was likely to be non-toxic to aquatic organisms and can be considered to be not classified as per the CLP regulations.
Executive summary:

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 1-(3-aminophenyl)urea (25711-72-2). EC50 value was estimated to be 103.62 mg/l for Pseudokirchneriella subcapitata for 72 h duration. Based on the value, the 1-(3-aminophenyl)urea (25711-72-2) was likely to be non-toxic to aquatic organisms and can be considered to be not classified as per the CLP regulations.

Description of key information

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 1-(3-aminophenyl)urea (25711-72-2). EC50 value was estimated to be 103.62 mg/l for Pseudokirchneriella subcapitata for 72 h duration.

Key value for chemical safety assessment

EC50 for freshwater algae:
103.62 mg/L

Additional information

Toxicity to algae and cyanobacteria for 1-(3-aminophenyl)urea (25711-72-2) was summarised with predicted data for target and by using functional read across studies as follows:

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 1-(3-aminophenyl)urea (25711-72-2). EC50 value was estimated to be 103.62 mg/l for Pseudokirchneriella subcapitata for 72 h duration.

In another prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance 1-(3-aminophenyl)urea  (CAS:25711-72-2). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 4277.416 mg/l for Species for 96 hrs duration.

Toxicity to algae test was performed in read across 3 Aminophenol from J-check database (2017). After 72 hrs the EC 50 and NOEC value for 3-aminophenol was determined. The EC 50 value and NOEC value for 3 Aminophenol for algae was determined to be 160 and 25 mg/l on the basis of growth rate and 62 and 25 mg/l on the basis of biomass. Thus, based on the value of EC50 for growth rate, the 3 aminophenol was likely to be non-toxic to algae and can be considered to be not classified as per the CLP regulations.

Based on the all the weight of evidences, it was considered that 1-(3-aminophenyl)urea (25711-72-2) was likely to be non-toxic to aquatic organism and can be considered to be not classified for short term toxicity to aquatic algae as per the CLP regulations.