Benzimidazole-2-thiol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data is from computational model developed by USEPA

Justification for type of information:

Data is from computational model developed by USEPA

Qualifier:

according to guideline

Guideline:

other: Modeling database

Principles of method if other than guideline:

ECOSAR estimates log Kow values using the US EPA's KOWWIN Program for aquatic toxicity.Toxicity of a chemical was measured on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program based upon the octanol /water partition coefficient (Kow). Data from ECOSAR class,neutral organics was used.

The estimation methods in EPI Suite™ have been developed by government, academic, and private sector researchers over many years and represent some of the best techniques currently available. The intended application domain of EPI Suite is organic chemicals, and inorganic as well as organometallic chemicals generally can be considered outside the domain.

GLP compliance:

no

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

80.912 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Neutral Organics

Validity criteria fulfilled:

not specified

Conclusions:

On the basis of EPI suite, ECOSAR version 1.1, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 80.912 mg/l for test material in 48 hrs.
Based on this value it can be concluded that the substance is considered to be toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

Executive summary:

Based on the prediction done by EPI suite, ECOSAR version 1.1, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted.

On the basis of EPI suite, ECOSAR version 1.1, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 80.912 mg/l for test material in 48 hrs.

Based on this value it can be concluded that the substance is considered to be  toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

Description of key information

Short-term toxicity to aquatic invertebrates:

Based on the prediction done by EPI suite, ECOSAR version 1.1, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted.

On the basis of EPI suite, ECOSAR version 1.1, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 80.912 mg/l for test material in 48 hrs.

Based on this value it can be concluded that the substance is considered to be  toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

80.912 mg/L

Additional information

Short-term toxicity to aquatic invertebrates:

The effect of test material was evaluated based on the predicted data for test chemical and further the prediction was supported by data for structurally similar read across substance.

Based on the prediction done by EPI suite, ECOSAR version 1.1, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted.

On the basis of EPI suite, ECOSAR version 1.1, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 80.912 mg/l for test material in 48 hrs.Based on this value it can be concluded that the substance is considered to be  toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

The above prediction was supported by data for structurally similar read across substance , experimental study for inhibition of the mobility of daphnids was carried out with the benzimidazole according to OECD Guideline 202. The animals used for the test shall be less than 24 h old and should not be of first brood progeny. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with reconstituted test water. The test substance was tested at the concentrations 0, 7.5, 15, 30, 60 and 120 mg/L. The test was performed under static conditions in a static fresh water system at 20±1°C temperature. Effects on immobilisation were observed for 48 hours. EC50 was calculated using non linear regression by the software Prism 4.0. After the experiment, the median effective concentration (EC50) for the test substance, benzimidazole, in Daphnia magna was determined to be 55.5 mg/L on the basis of immobilisation effects. Based on the EC50 value chemical consider to be toxic and classified as aquatic chronic 3 as per the CLP classification criteria.

Further for another structurally similar read across substance ,determination of the inhibition of the mobility of daphnids was carried out with the substance according to OECD Guideline 202. The stock solution (200 g/L) was prepared by dissolving white powder in DMSO. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with reconstituted test water. The test substance was tested at the concentrations 0, 5, 10, 20, 30, 40, 80 mg/L and the immobilisation effects were observed for 48 hours. Effects on immobilisation were observed for 48 hours. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. The median effective concentration (EC50) for the test substance, in Daphnia magna was determined to be 26 mg/L on the basis of mobiity inhibition effects in a 48 hour study. This value indicates that the substance is likely to be hazardous to aquatic invertebrates can can be classified as Aquatic chronic category 3 as per the CLP criteria.

The above data was supported by data for another structurally similar read across substance , determination of the inhibition of the mobility of daphnids was carried out with the substance,according to OECD Guideline 202.The stock solution (100 g/L) was prepared by dissolving white powder in acetone. The test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with reconstituted test water. The test solution were kept 10 min in ultrasonic bath.The test substance was tested at the concentrations 0, 6, 10, 17, 29, 50 and 100 mg/L. Effects on immobilisation were observed for 48 hours. The median effective concentration (EC50) for the test substance, in Daphnia magna was determined to be 29.8 mg/L for immobilisation effects.

These value indicates that the substance is likely to be hazardous to aquatic invertebrates and can be classified as Aquatic Chronic category 3 as per the CLP criteria.