2-tert-butylhydroquinone

Endpoint summary

Description of key information

Short term toxicity to fish:

Study was conducted to access the effect of test chemical to fish Danio rerio. Test conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test). The test solution was prepared by dissolving the test substance in 1 liters of potable water (passed through reverse osmosis system) with continuous stirring. The nominal concentrations of the test chemical ranging from 0.18 o 2.4 mg/L was taken for the study and exposed to these concentrations for 96 hours. A static procedure was used for the study and it was conducted in compliance with the OECD guideline 203. After 96 hours of exposure to test chemical to various nominal test concentrations, LC50 was determine to be >0.3 - <0.48 mg/L. . Based on the LC50, it can be consider that the chemical can be consider to be classified in to aquatic acute category 1 as per the CLP classification criteria.

Long term toxicity to fish:

Using the EPI Suite, the long term toxicity on fish was predicted for test substance. On the basis of no effects observed in a flow-through freshwater system, the no observed effect concentration (NOEC) value for the substance is estimated to be 0.004 mg/l for fish for 28 d duration.

 

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. A range of concentrations from 0.25 to 4 mg/L 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 to Daphnia magna was determined to be 0.57 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 acute category 1 as per the CLP classification criteria.

Long term toxicity to aquatic invertebrate:

1: 21d-LC50 = 0.131 mg/L (95% confident interval: 0.112 – 0.157 mg/L)

21d-EC50% Reproduction Inhibition = 0.116 mg/L (95% confident interval: 0.0991 – 0.137 mg/L)

21d-NOECreproduction = 0.050 mg/L

21d-LOECreproduction = 0.10 mg/L

All of the above concentrations are the values based on nominal values

2: Effect of test chemical was studied, on daphnia magna on their reproduction ability. based on the observed data, the NOEC can be determined as 0.25 mg/L.

Thus based on both studies, chemical consider to be toxic and classified as aquatic chronic 2 as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Aim of this study was to evaluate the toxic nature of test chemical, when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. Various concentrations ranging from 1.0 to 20.0, along with one positive control Potassium dichromate (K2Cr2O7). After the exposure of chemical, median effective concentration EC50 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. The median effective concentration (ErC50) for the test substance to algae was determined to be 9.3 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 2, category as per the CLP classification criteria.

Toxicity to microorganisms:

Toxicity of test chemical on the microorganisms were studied by using Agar-plate test. Test conducted under the static system. Five replicates were used; radial fungal growth normalized to fungal growth on control plates was observed; IC50 value was calculated by regression of relative growth versus log of concentration. The IC50 value of test chemical for Gloeophyllum trabeum ATCC 11539 is observed to be < 200 mg/L.

 

Additional information

Short term toxicity to fish:

Summarized result for the toxicity of test chemical were studied and mention as below:

The first experimental key study was conducted to access the effect of test chemical to fish Danio rerio. Test conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test). The test solution was prepared by dissolving the test substance in 1 liters of potable water (passed through reverse osmosis system) with continuous stirring. The nominal concentrations of the test chemical ranging from 0.18 o 2.4 mg/L was taken for the study and exposed to these concentrations for 96 hours. A static procedure was used for the study and it was conducted in compliance with the OECD guideline 203. After 96 hours of exposure to test chemical to various nominal test concentrations, LC50 was determine to be >0.3 - <0.48 mg/L. . Based on the LC50, it can be consider that the chemical can be consider to be classified in to aquatic acute category 1 as per the CLP classification criteria.

 

First study was supported by the second study from peer reviewed journal. Static toxicity tests were performed according to ASTM standard methods for fish. Test conducted under the static system for 48 hrs on Channel catfish. After the exposure of chemical with fish, effect on the mortality were observed. The LC50 (48 hr) value of test chemical to Ictalurus punctatus in 48 hours study on basis of effect of mortality was reported to be 0.37 mg/L. Thus based on the LC50 value, chemical consider to be toxic and classified as aquatic acute 1 as per the CLP classification criteria.

 

Similar static toxicity tests were performed according to ASTM standard methods for fish. Lepomis macrochirus exposed with chemical for 48 hrs. Fish were not fed during the experiment. In a 20-L glass jar, 15 L well water was used for the test. Mortality was measured at 1, 3, 6, 24, 48 hours. After the exposure of test chemical to Lepomis macrochirus in 48 hours study is reported to be 0.15 mg/L based on the mortality of fish. Thus chemical consider to be toxic and classified as aquatic acute 1 as per the CLP classification criteria.

 

Based on the above all studies from various sources, chemical consider to be toxic and classified in aquatic acute 1 category as per the CLP classification criteria.

 

Long term toxicity to fish:

Using the EPI Suite, the long term toxicity on fish was predicted for test substance. On the basis of no effects observed in a flow-through freshwater system, the no observed effect concentration (NOEC) value for the substance is estimated to be 0.004 mg/l for fish for 28 d duration.

 

Short term toxicity to aquatic invertebrate:

Summarized result from various experimental report and peer reviewed journal were studied and mention as below:

 

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. A range of concentrations from 0.25 to 4 mg/L 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 to Daphnia magna was determined to be 0.57 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 acute category 1 as per the CLP classification criteria.

 

Similar test chemical was tested for its potential for preventing the attachment of zebra mussels Dreissena polymorpha.15 zebra mussels (5–8-mm shell length) in each of two replicates and six treatments were exposed for 48 h followed by a 48-h postexposure period in untreated water. The EC50 (48hr) value of test chemical to Dreissena polymorpha is observed at 1 mg/L based on its ability to detach from substrate. Based on this effect, chemical can be classified as aquatic acute category 1 as per the CLP classification criteria.

 

Thus based on the above both studies, chemical consider to be toxic and classified as aquatic acute 1 category as per the CLP classification criteria.

 

Long term toxicity to aquatic invertebrate:

Summarized result from various experimental report and peer reviewed journal for test chemical and structurally and functionally similar read across chemical were studied, reviewed and mention as below:

 

The purpose of the first study was to determine the long term effect over 21 days of the test item on Daphnia magna, according to the OECD 202 guideline and following GLP. Forty daphnids (10 animals per replicate, 4 replicates), were used per concentration level and control. At test start the daphnids were ared 24 hours old or less. The study was carried out under flow-through conditions. Aim of the test was to assess the effects on the reproduction capacity and other test item-related effects or parameters such as the first appearance of living juveniles, occurrence of resting eggs, adult mortality, size and conditions of parental animals. Nominal concentrations of the test item were as follows: 0.40 – 0.20 – 0.10 – 0.050 – 0.0250 mg/L. The test item concentrations were analytically verified via HPLC (High Performance Liquid Chromatography) on days 0, 3, 7, 14 and 21. The measured values of test substance concentration during exposure period were 0.0202 – 0.454 mg/L (nominal value 0.0250 – 0.40 mg/L), which were in the range 74.1 – 120% of the nominal concentrations. The environmental conditions were within the acceptable limits. The validity criteria of the OECD 202 test guideline were met. Based on the above results chemical consider to be classified as aquatic acute 1/ chronic 1 as per the CLP classification criteria.

21d-LC50 = 0.131 mg/L (95% confident interval: 0.112 – 0.157 mg/L)

21d-EC50% Reproduction Inhibition = 0.116 mg/L (95% confident interval: 0.0991 – 0.137 mg/L)

21d-NOECreproduction = 0.050 mg/L

21d-LOECreproduction = 0.10 mg/L

All of the above concentrations are the values based on nominal values.

 

First study was supported by the second study. The test chemical was studied to understand its effect on reproduction of test model daphnia magna. The test was conducted as per OECD guidelines 211. The test was conducted for the period of 21 days in a semi static type of exposure.

A range of concentration was taken i.e., 0.125 to 2 mg/L with the geometric ratio of 2. Based on the output obtained after 21 days study, the NOEC was determined as 0.25 mg/L. As per CLP criteria the test chemical can be classified into aquatic chronic category 2.

 

Thus based on both studies, chemical consider to be toxic and classified as aquatic chronic 2 as per the CLP classification criteria.

 

Toxicity to aquatic algae and cyanobacteria:

Aim of this study was to evaluate the toxic nature of test chemical, when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. Various concentrations ranging from 1.0 to 20.0, along with one positive control Potassium dichromate (K2Cr2O7). After the exposure of chemical, median effective concentration EC50 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. The median effective concentration (ErC50) for the test substance to algae was determined to be 9.3 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, which indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 2, category as per the CLP classification criteria.

 

Toxicity to microorganisms:

Summarized result from various sources and peer reviewed journal were studied and mention as below:

In the first study toxicity of test chemical on the microorganisms were studied by using Agar-plate test. Test conducted under the static system. Five replicates were used; radial fungal growth normalized to fungal growth on control plates was observed; IC50 value was calculated by regression of relative growth versus log of concentration. The IC50 value of test chemical for Gloeophyllum trabeum ATCC 11539 is observed to be < 200 mg/L.

 

Toxicity study under the static system was performed on White-rot fungus. Test solution prepared by using acetone as a vehicle. The IC50 value of test chemical for Trametes versicolor ATCC 12679 is < 200 mg/L.

 

Above study was supported by the third study from peer reviewed journal. Static test for 5 weeks were performed on Gloeophyllum trabeum ATCC 11539. Laboratory decay test; soil-block test; SYP sapwood wafers treated with test chemical and exposed to the brown-rot fungus for 5 weeks. Extent of degradation measured by compression strength loss in radial direction. Treatment with concentration of 5 % were used. In Gloeophyllum trabeum ATCC 11539 (brown-rot fungus), treatment with test chemical for 35 days, results in average percent strength loss of 9.2% as compared to 83.0-99.1% in control at 5% concentration of test chemical.

Thus based on the above short and long term effects on fish, invertebrates and algae, chemical consider to be toxic and classified as aquatic acute 1 and chronic 2 as per the CLP classification criteria.