β-bromostyrene

Endpoint summary

Description of key information

Short term toxicity to fish:

Using the EPI Suite ECOSAR version, the short term toxicity on fish was predicted for test substance on the basis of effects observed in a static freshwater system. The lethal concentration LC50 value for the substance was estimated to be 13.842 mg/l for fish for 96 hr duration. Based on this value it can be concluded that the substance can be considered to be toxic to aquatic environment and can be classified in aquatic chronic category 3 as per the CLP classification criteria. But as the chemical was readily biodegradable in water, thus on that criteria chemical consider to be nontoxic and not classified as per the CLP classification criteria.

Short term toxicity to aquatic invertebrate:

Aim of this study was to assess the short term toxicity of test chemical to aquatic invertebrate daphnia magna. Study was performed according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) in a static system for the total exposure period of 48 hrs. The stock solution100 g/l was prepared by dissolving colourless liquid in DMSO. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with reconstituted test water. 0, 0, 1, 2, 4 8 and 16 mg/l concentrations were used in the study. 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 6.1 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, substance is likely to be hazardous to aquatic invertebrate and can be classified as aquatic chronic 2 category as per the CLP classification criteria. But as the chemical is readily biodegradable in water, thus on that criteria chemical consider to be nontoxic and not classified as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Objective of this study was to observe the nature of test chemical when it exposed with the green algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) for 72 hrs. Test conducted in accordance with OECD Guideline 201 (Alga, Growth Inhibition Test). The stock solution 100 g/l was prepared by dissolving colourless in DMSO. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. The substance formed a few small balls in the growth medium above the concentration of 58 mg/l. 0, 0, 10, 18, 32, 58 and 100 mg/l nominal concentrations were used in the study. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration ErC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs. Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of chemical for 72 hrs, the ErC50 was determine to be 50.4 mg/l. Based on the ErC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 3 category as per the CLP classification criteria. But as the chemical is readily biodegradable in water, thus on that basis, it states that the chemical was nontoxic and not classified as per the CLP classification criteria.

Toxicity to microorganism:

WoE 2: Test chemical has showed 50% respiration inhibition of activated sludge at a concentration of 71 mg/l.

WoE 3: The Inhibition concentration (IC50) of test material in tetrahymena pyriformis was observed to be 161.27 mg/L on the basis of population growth rate effect in a 48 hours of exposure.

WoE 3: The impairment growth concentration (IGC50) of test chemical in microorganism [Tetrahymena pyriformis] in a 48 hr study on the basis of growth inhibition effect using a short-term, static protocol was datarmine to be 377 mg/L.

Thus on the basis of above studies, chemical consider to be nontoxic.

Additional information

Short term toxicity to fish:

Various experimental studies and predicted data available for the test chemical and structually and functionally similar read across chemicals were reviewed to determine the toxic nature of test chemical on the growth and other activity of microorganisms. The studies are as mentioned below:

 

In the first data using the EPI Suite ECOSAR version, the short term toxicity on fish was predicted for test substance on the basis of effects observed in a static freshwater system. The lethal concentration LC50 value for the substance was estimated to be 13.842 mg/l for fish for 96 hr duration. Based on this value it can be concluded that the substance can be considered to be toxic to aquatic environment and can be classified in aquatic chronic category 3 as per the CLP classification criteria. But as the chemical was readily biodegradable in water, thus on that criteria chemical consider to be nontoxic and not classified as per the CLP classification criteria.

Similar prediction done using average value of both models i.e Leadscope and SciMatics SciQSAR model and the result were predicted in Battery model. Based on the QSAR prediction done using the Danish (Q)SAR Database, the 96 hours LC50 was estimated to be 4.41 mg/l on Pimephales promelas for test substance with mortality effects. Thus based on this readily biodegradability of test chemical, it can be concluded that the substance cannot be classified as toxic as per the criteria of CLP regulation.

Above predicted data was supported by the experimental data. This study outlines the effects of the test chemical on the mortality rate of the zebrafish at an exposure period of 96 hours. Test chemical was dissolved in the synthetic fresh water and fishes were exposed to test chemical in semi static condition. Where the chemical was renewed after every 24 hours till 4 days. Nominal concentrations were selected to treat the fishes with test chemical, based on the mortality observation, LC0 and LC100 was determined as 1.41 mg/L and 3.93 mg/L for 24 hrs, respectively. The geometric mean of LC0 and LC100 was observed to be 2.95 mg/L (24hr). Since the test substance is readily biodegradable and BCF is <500, it can be nontoxic to aquatic environment, and cannot be classified.

The fourth study was designed to assess the toxic effects of the test compound on the Oncorhynchus mykiss (Rainbow  trout) in a 24 hr study period. Test conducted under the static system for 24 hrs. The no observed effect concentration (NOEC) value of test chemical on fish [Oncorhynchus mykiss] in a 24 hr study was determine to be 5 mg/L. Thus chemical consider to be nontoxic.

In the fifth 96 hrs short term toxicity study was conducted on BluegillLepomis macrochirusfor the test compound. Concentration selected for the study was 1.97 mg/L.

Since no mortality was noted, the No Observed Effect Concentration (NOEC) for the test compound is reported as 1.97 mg/L. Since the substance test compound is readily biodegradable and also BCF is less than 500 thus it can be considered as not toxic to aquatic environment and cannot be classified as per the new CLP guidelines.

Thus based on the above all data and results, chemical consider to be nontoxic and not classified as per the CLP classification criteria.

Short term toxicity to aquatic invertebrate:

Aim of this study was to assess the short term toxicity of test chemical to aquatic invertebrate daphnia magna. Study was performed according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) in a static system for the total exposure period of 48 hrs. The stock solution100 g/l was prepared by dissolving colourless liquid in DMSO. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with reconstituted test water. 0, 0, 1, 2, 4 8 and 16 mg/l concentrations were used in the study. 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 6.1 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, substance is likely to be hazardous to aquatic invertebrate and can be classified as aquatic chronic 2 category as per the CLP classification criteria. But as the chemical is readily biodegradable in water, thus on that criteria chemical consider to be nontoxic and not classified as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Objective of this study was to observe the nature of test chemical when it exposed with the green algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) for 72 hrs. Test conducted in accordance with OECD Guideline 201 (Alga, Growth Inhibition Test). The stock solution 100 g/l was prepared by dissolving colourless in DMSO. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. The substance formed a few small balls in the growth medium above the concentration of 58 mg/l. 0, 0, 10, 18, 32, 58 and 100 mg/l nominal concentrations were used in the study. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration ErC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs. Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of chemical for 72 hrs, the ErC50 was determine to be 50.4 mg/l. Based on the ErC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 3 category as per the CLP classification criteria. But as the chemical is readily biodegradable in water, thus on that basis, it states that the chemical was nontoxic and not classified as per the CLP classification criteria.

Toxicity to microorganism:

Various studies available for the test chemical were reviewed to determine the toxic nature of test chemical on the growth and other activity of microorganisms. The studies are as mentioned below:

 

In the first study from experimental reportstudy performed to assess the toxicity of test chemical to bacteria.The study was conducted in accordance with ISO 8192. The activated sludge was exposed to test substance at different concentrations.The respiration rate of each mixture was determined after aeration period of 3 hours. Test chemical showed 50% respiration inhibition of activated sludge at a test substance concentration of 71 mg/l (EC50 =71 mg/l).

First study was supported by the second study from peer reviewed journal. A test was developed using Tetrahymena pyriformis in order to determine the toxicity of test material. The concentration of the chemical, at which the inhibition of test organism i.e T. pyriformis was observed (IC50), was determined. The Inhibition concentration (IC50) of test material in tetrahymena pyriformis was observed to be 161.27 mg/L on the basis of population growth rate effect in a 48 hours of exposure.

Similarly a short-term, static protocol using the common freshwater ciliate Tetrahymena pyriformis (strain GL-C) was reported. The 50% impairment growth concentration (IGC 50) is the endpoint of choice. Cultures were reared in 50 mL of a semi defined medium in 250-mL Erlenmeyer flasks. Definitive test replicates consisted of a minimum of 5 different concentrations of each test material. Duplicate flasks were inoculated to an initial density of 2500 cells/ mL with log-growth phase ciliates. Following 40 h of incubation at 27 deg C, population density was measured spectrophotometrically and 50% effect levels were determined.The impairment growth concentration (IGC50) of test chemical in microorganism [Tetrahymena pyriformis] in a 48 hr study on the basis of growth inhibition effect using a short-term, static protocol was datarmine to be 377 mg/L.

Thus on the basis of above studies, chemical consider to be nontoxic.

Hence on the basis of effects observation on fish, invertebrate and algae and also readily biodegradable nature of test chemical, chemical consider to be nontoxic and not classsified as per the CLP classification criteria.