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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
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:
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:
not specified
Specific details on test material used for the study:
- Name of the test material: α-bromo-m-toluonitrile
- IUPAC name: 3-(bromomethyl)benzonitrile
- Molecular formula: C8H6BrN
- Molecular weight: 196.046 g/mol
- Smiles: N#Cc1cc(CBr)ccc1
- Inchi: 1S/C8H6BrN/c9-5-7-2-1-3-8(4-7)6-10/h1-4H,5H2
- Substance type: Organic
- Physical state : Solid crystalline powder (Off white)
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Daphnia magna
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
250.08 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
other: Intoxication
Remarks on result:
other: not toxic

The prediction was based on dataset comprised from the following descriptors: EC50
Estimation method: Takes average value from the 7 nearest neighbours
Domain  logical expression:Result: In Domain

(((((((("a" or "b" or "c" or "d" or "e" )  and "f" )  and ("g" and ( not "h") )  )  and "i" )  and "j" )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and "p" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as SN2 OR SN2 >> SN2 reaction at sp3 carbon atom OR SN2 >> SN2 reaction at sp3 carbon atom >> Alkyl halides OR SN2 >> SN2 reaction at sp3 carbon atom >> alpha-Halobenzyls (and related cyano, sulfate and sulphonate subs. chem.) by Protein binding by OECD ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN2 OR SN2 >> Nucleophilic substitution at sp3 carbon atom OR SN2 >> Nucleophilic substitution at sp3 carbon atom >> Alkyl halides  OR SN2 >> Nucleophilic substitution on benzilyc carbon atom OR SN2 >> Nucleophilic substitution on benzilyc carbon atom >> alpha-Activated benzyls  by Protein binding by OASIS v1.3 ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as SN2 OR SN2 >> SN2 at an sp3 Carbon atom OR SN2 >> SN2 at an sp3 Carbon atom >> Aliphatic halides by DNA binding by OECD ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Shiff base formation for aldehydes OR AN2 >> Shiff base formation for aldehydes >> Haloalkane Derivatives with Labile Halogen OR SN2 OR SN2 >> Acylation involving a leaving group  OR SN2 >> Acylation involving a leaving group  >> Haloalkane Derivatives with Labile Halogen OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Haloalkane Derivatives with Labile Halogen by DNA binding by OASIS v.1.3 ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as SN2 AND SN2 >> Nucleophilic substitution at sp3 carbon atom AND SN2 >> Nucleophilic substitution at sp3 carbon atom >> Alkyl halides  AND SN2 >> Nucleophilic substitution on benzilyc carbon atom AND SN2 >> Nucleophilic substitution on benzilyc carbon atom >> alpha-Activated benzyls  by Protein binding by OASIS v1.3 ONLY

Domain logical expression index: "g"

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: "h"

Referential boundary: The target chemical should be classified as Extremely reactive (GSH) OR Extremely reactive (GSH) >> 2-bromo dinitriles (SN2) OR Slightly reactive (GSH) OR Slightly reactive (GSH) >> Substituted haloacetamides (SN2) by Protein binding potency

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Class 3 (unspecific reactivity) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Group 14 - Carbon C AND Group 15 - Nitrogen N AND Group 17 - Halogens Br AND Group 17 - Halogens F,Cl,Br,I,At by Chemical elements

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Group 16 - Oxygen O by Chemical elements

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Alkyl halide AND Aryl AND Benzyl AND Nitrile by Organic Functional groups

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Perhalogenated carbons derivatives by Organic Functional groups

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of log Kow which is >= 1.18

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of log Kow which is <= 2.56

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 to invertebrate was predicted 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) EC50 intoxication value was estimated to be 250.08 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) was likely to be not toxic to invetebrates.

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 to invertebrate was predicted 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) EC50 intoxication value was estimated to be 250.08 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) was likely to be not toxic to invetebrates.

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 to invertebrate was predicted 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) EC50 intoxication value was estimated to be 250.08 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) was likely to be not toxic to invetebrates.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
250.08 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 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) towards invertebrate 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 to invertebrate was predicted 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) EC50 intoxication value was estimated to be 250.08 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) was likely to be not toxic to invetebrates.

The predicted data for the target chemical is supported by the experimental study of structurally similar read aross 1 -chlorobutane (CAS: 109 -69 -3) from the publication Water Research 1989, suggests that the Short-term toxicity to aquatic invertebrates test was carried out according to the EU method C 2 (Acute toxicity to Daphnia). Test was carried out with 6 to 24 hr aged Daphnia magna under static condition at Hardness: 2.4 mmol/L, Test temp: 20 °C, pH: Test begin: 8.0 ± 0.2Test end: >7 and Dissolved oxygen: >4.0 mg/L O2.

The test vessels were two 50 ml beakers and for volatile or strongly smelling substances, two 50 ml bottles with ground-glass stoppers, each with 20 ml useful capacity. Two parallel preparations were made for each concentration step. Loading amounted to one test animal per 2 ml test medium as ten 6-24 h old daphnids were placed in each test and control vessel, i.e. 20 animals per concentration step. After a test period of 24 h and again after 48 h, the number of animals in the control and test solutions that could still swim were counted.

The Effective concentration EC50 to 50% of Daphnia magna for 1-chlorobutane in 48 h is 3020 mg/L. It can be concluded form the value that the 1-chlorobutane is no toxic to the aquatic environment and can be considered as “not classified” as per the classification criteria for aquatic environment.

Similar supporting exeprimental study of another structurally similar read aross 1,1,2 -trichloroethane (CAS:79 -00 -5) from the publication Archives of Environmental Contamination and Toxicology 1983, also suggests that the Acute bioassay was carried for 1,1,2-trichloroethane on daphnia magna for 48 hr to study the effects on aquatic invertebrate. The test was carried out with 5 Daphnia magna at under static conditions and the test conditions were Hardness: 44.7 (43.5 TO 47.5) mg/L CaCO3, Test temp: 20 C, pH: 7.0 TO 7.5 and Dissolved oxygen: 4.1 TO 8.4 mg/L

Test containers were 200 ml Erlenmeyer flasks filled to 200 or 160 ml for unfed and fed tests, respectively. The food concentration was 20 rag/ L dry wt. (trout chow and yeast). The flasks were stoppered with foil wrapped, neoprene stoppers. Four replicates with five animals each were used for the control and six toxicant levels.

Lethal concentration to 50% of Daphnia magna in 48 hr is 170 mg/L. It can be concluded from the value that the 1,1,2-trichloroethane is no toxic to the aquatic invertebrate and can be considered as “not classified” as per the classification criteria for aquatic environment.

Thus based on the effect concentrations which is in the range 170 mg/l to 3020 mg/l give the conclusion that test substance 3-(bromomethyl)benzonitrile (CAS: 28188-41-2) was likely to be not toxic to aquatic invertebrate at environmentally relevant concentrations and applying weight of evidence approach it can be considered to benot classifiedas per the CLP classification criteria.