Benzonitrile, 4-bromo-2-chloro-

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2015

Materials and methods

Principles of method if other than guideline:

The acute toxicity on Daphnia was estimated by using ACD/Percepta, ECOSAR and Vega predictor.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-bromo-2-chlorobenzonitrile

EC Number:

679-039-6

Cas Number:

154607-01-9

Molecular formula:

C7H3BrClN

IUPAC Name:

4-bromo-2-chlorobenzonitrile

Test organisms

Test organisms (species):

Daphnia magna

Results and discussion

Effect concentrations

Dose descriptor:

LC50

Effect conc.:

6.22 mg/L

Remarks on result:

other: Consensus (moderate reliable)

Any other information on results incl. tables

ACD/PerceptaLC50 (mg/L)	ECOSARLC50 (mg/L)	Consensus predictionLC50 (mg/L)
2.3 (moderate reliable)	12.09 (Moderate Reliable)	6.22 (Moderate Reliable)

ACD/Percepta model for aquatic toxicity calculates acute toxicity expressed as LC₅₀value for water fleas (Daphnia magna),based on the GALAS methodology.Reliability of predictions is estimated in terms of reliability index (RI),which ranges from0 to 1 and takes into account the similarity of the 4-bromo-2-chlorobenzonitrile with the training set compounds and the consistency of experimental values for similar compounds.

ACD/PerceptaLC50 (mg/L)	ACD/Percepta RI	Reliability assessment
2.3	0.58	MODERATE RELIABLE

ACD/Percepta provided a prediction of LC₅₀equal to 2.3 mg/L. The prediction was assessed as moderate reliable being the reliability index equal to 0.58.ACD/Percepta displays the most structurally similar structures from the training set along with their experimental test results. The information on the structurally similar compounds in the training set was used to further assess the reliability of the prediction. Two training compounds were identified as analogues (similarity greater than 0.5) of 4-bromo-2-chlorobenzonitrile

ECOSAR

Acute toxicity on Daphnia (LC₅₀48h) was predictedusingLogKow-based QSARsthat are specific for the chemical class(es) identified for the 4-bromo-2-chlorobenzonitrile compound.Predictions provided by ECOSAR are not supported by a specific parameter for reliability assessment, however the MW range of the training set compounds and a LogKow cut-off equal to 5.0 are used to define the limits of the applicability domain of the model. ECOSAR predictions are illustrated in Table:

ECOSAR (48 hr)LC50 (mg/L)	Applicability domain	Reliability assessment
12.09	Maximum LogKow = 5.0	Moderate RELIABLE

 

ECOSAR assignedthe target chemical 4-bromo-2-chlorobenzonitrile to the class of Neutral organics, since no specific chemical class among the ECOSAR classes was identified. Based on the Neutral Organics QSAR equation, which represents baseline toxicity potential (minimum toxicity) assuming a simple non-polar narcosis model, ECOSAR predicted for the target compound an acuteLC₅₀to Daphnia equal to 12.09mg/L. Without empirical data on structurally similar chemicals, it is uncertain if this substance will present significantly higher toxicity above baseline estimates.Based onMW range and logKow cut-off, it was assumed that target 4-bromo-2-chlorobenzonitrilefallsinside the applicability domain of the model.

Applicant's summary and conclusion

Conclusions:

Acute aquatic toxicity on Daphnia of the 4-bromo-2-chlorobenzonitrile chemical was estimated by using two predictors: ACD/Percepta and ECOSAR. The two predictors were employed in order to apply a consensus approach to enhance the reliability of the predictions. In the consensus assessment only reliable predictions are to be taken into account. Both ACD/Percepta and ECOSAR predictions were considered moderate reliable. Thus, since ACD/Percepta provides an assessment the reliability of its prediction a more detailed than ECOSAR, the consensus prediction was computed weighting ACD/Percepta prediction (weight = 0.6) more than ECOSAR prediction (weight = 0.4) and leading to a moderate reliable acute 48-h LC50 in Daphnia equal to 6.22 mg/L.