Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Short term toxicity to fish:

Study was conducted to access the effect of test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole) on the growth of fish Danio rerio. Test conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test). The test substance was partially soluble in RO water. Therefore, the stock solution was prepared by dissolving 4 g of the test substance in 4 liters of potable water (passed through reverse osmosis system) with continuous 72 hrs stirring, After stirring the stock solution was analytically detected and the stock concentration was found to be 0.7309 mg/l, On the basis of this value limit test was set up with this concentration 0.7309 mg/L ,respectively and Zebra Fish Danio rerio were exposed to these concentration for 96 hours. Bowl aquaria containing 2 liters of potable water (passed through reverse osmosis system) were loaded with 8 fishes. A static procedure was used for the study and it was conducted in compliance with the OECD guideline 203. Test consider to be valid as all the conditions available according to the OECD guidelines. The mortality in the control not exceed 0 per cent at the end of the test. The constant conditions maintained as far as possible throughout the test and, semi-static procedures used. The dissolved oxygen concentration >60 per cent of the air saturation value throughout the test. After 96 hours of exposure to test item to limit concentrations, LC50 was determine to be > 0.7309 mg/l. As the chemical was slightly soluble in water and mortality was observed to be > 0.7309 mg/l, thus on that basis chemical cannot be consider to be toxic and not classified as per the CLP classification criteria.

 

Short term toxicity to aquatic invertebrates:

Daphnia sp., Acute Immobilization Test according to OECD Guideline 203 was conducted for test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole). The test substance was partially soluble in water. Therefore, the stock solution was prepared by dissolving 500 mg of the test substance in 500 ml of ADaM’s media. Kept it for 72 hrs stirring. After stirring the stock solution was analytically detected and the stock concentration was found to be 0.6450 mg/L. Limit test was set up with this concentration only and test Daphnia magna were exposed to these concentration for 48 hours. Test conducted under the semi-static system in which 25 ml of glass beaker filled with 20 ml media having headspace of 5 ml were used. Based on nominal concentrations, experimental median effective Concentrations [EC-50 (48 h)] for test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole) on test daphnia was determine to be > 0.6450 mg/L. Test consider to be valid as fulfils all the criteria as per standards. 1. In the control, including the control containing the solubilizing agent, not more that 10 percent of the daphnids should have been immobilized.  2. The dissolved oxygen concentration at the end of the test should be 3 mg/l in control and test vessels. As the chemical was slightly soluble in water and test conducted at higher solubility value i.e. > 0.6450 mg/l at which no mobility were observed, thus on that basis chemical cannot be consider to be toxic and not classified as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Based on the growth inhibition of green alga Chlorella vulgaris by the test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole), the EC50 was determine to be 2.391 mg/l. Based on the EC50, it can be concluded that the chemical was toxic and can be consider to be classified as aquatic chronic 2 as per the CLP classification criteria.

 

Toxicity to microorganisms:

1. The Effective Concentration causing 50% mortality of luminescent bacteria Photobacteria phosphereum was determine to be 3.35 mg/l after 30 minutes exposure with test chemical.

2. The Effective Concentration causing 50% mortality of luminescent bacteria Photobacteria phosphereum was determine to be 5.43 mg/l and 6.83 mg/l after 30 minutes exposure with test chemical.

Thus based on the overall studies, it was concluded that the test chemical was toxic and the toxic concentration ranges from 3.35 mg/l to 6.83 mg/l.

Additional information

Summarized result for the toxicity of test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole) (CAS No. 1533-45-5) on the growth of aquatic fish, aquatic invertebrates, algae and microorganisms are as follows:

 

Short term toxicity to fish:

Study was conducted to access the effect of test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole) on the growth of fish Danio rerio. Test conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test). The test substance was partially soluble in RO water. Therefore, the stock solution was prepared by dissolving 4 g of the test substance in 4 liters of potable water (passed through reverse osmosis system) with continuous 72 hrs stirring, After stirring the stock solution was analytically detected and the stock concentration was found to be 0.7309 mg/l, On the basis of this value limit test was set up with this concentration 0.7309 mg/L ,respectively and Zebra Fish Danio rerio were exposed to these concentration for 96 hours. Bowl aquaria containing 2 liters of potable water (passed through reverse osmosis system) were loaded with 8 fishes. A static procedure was used for the study and it was conducted in compliance with the OECD guideline 203. Test consider to be valid as all the conditions available according to the OECD guidelines. The mortality in the control not exceed 0 per cent at the end of the test. The constant conditions maintained as far as possible throughout the test and, semi-static procedures used. The dissolved oxygen concentration >60 per cent of the air saturation value throughout the test. After 96 hours of exposure to test item to limit concentrations, LC50 was determine to be > 0.7309 mg/l. As the chemical was slightly soluble in water and mortality was observed to be > 0.7309 mg/l, thus on that basis chemical cannot be consider to be toxic and not classified as per the CLP classification criteria.

 

Short term toxicity to aquatic invertebrates:

Daphnia sp., Acute Immobilization Test according to OECD Guideline 203 was conducted for test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole). The test substance was partially soluble in water. Therefore, the stock solution was prepared by dissolving 500 mg of the test substance in 500 ml of ADaM’s media. Kept it for 72 hrs stirring. After stirring the stock solution was analytically detected and the stock concentration was found to be 0.6450 mg/L. Limit test was set up with this concentration only and test Daphnia magna were exposed to these concentration for 48 hours. Test conducted under the semi-static system in which 25 ml of glass beaker filled with 20 ml media having headspace of 5 ml were used. Based on nominal concentrations, experimental median effective Concentrations [EC-50 (48 h)] for test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole) on test daphnia was determine to be > 0.6450 mg/L. Test consider to be valid as fulfils all the criteria as per standards. 1. In the control, including the control containing the solubilizing agent, not more that 10 percent of the daphnids should have been immobilized.  2. The dissolved oxygen concentration at the end of the test should be 3 mg/l in control and test vessels. As the chemical was slightly soluble in water and test conducted at higher solubility value i.e. > 0.6450 mg/l at which no mobility were observed, thus on that basis chemical cannot be consider to be toxic and not classified as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

 The study was designed to assess the toxic effects of the test compound 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole) on the green alga Chlorella vulgaris. Test was conducted in compliance with the OECD guideline 201 (Alga, Growth Inhibition Test). Test was carried out in 100mL conical flasks which were carefully autoclaved and sterilized. The test solution in each of these test vessels was kept constant which is 60 ml so that a sufficient amount of head space was left. The test solution was prepared in aseptic condition. The test item was prepared by adding 1g of test item in 1000 ml of BBM to get the final concentration of 2.432mg/L. This stock solution was kept for stirring for 72 hours to obtain a homogenous solution for the experiment. The test concentrations were chosen according to the available data of the test item. The concentrations chosen were set up to the water solubility limit. The remaining test solutions were prepared by dilution from the above stock solution. To have a better growth and visibility of cells, the initial cell density of the culture was kept 1 X 10000cells/ml. Care was taken to have a homogeneous solution for the experiment. 0.977mg/l,1.173mg/l,1.407mg/l,1.689mg/l, 2.027mg/l, 2.432mg/l nominal concentrations were used in the study. All the six concentration were in geometric series spaced by a factor of 2. For the assessment of algal growth, the test was conducted in replicates. The control flask was maintained in triplicates as recommended in the OECD guideline and the test concentration were selected in geometric series which were maintained in duplicates. To obtain a quantitative concentration-response relationship by regression analysis, a linearizing transformation of the response data into probit was performed. Using the same, effective concentration (EC) were determined. Algal growth was calculated daily by counting the cells microscopically with the help of haemocytometer. For microscopic observations the cultures were observed daily with the help of a microscope to verify a normal and healthy appearance of the algal culture and also to observe any abnormal appearance of the algae (as may be caused by the exposure of the test item). Apart from this, the cell count of each test vessel was also noted with the help of a microscope and haemocytometer. By spectrophotometer the absorbance values of each test vessel and control vessel was noted at 680nm.The BBM was taken as blank for both control and test vessels. The absorbance value of each vessel was in line with the average specific growth rate. As per OECD 201, the biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72 hr test period. This corresponds to a specific growth rate of 0.92 per day. Thus, the observed specific growth rate in the control cultures during the experiment was 0.358 per day. Secondly the mean coefficient of variation for section by section specific growth rates (days 0-1, 1-2 & 2-3, for 72 hr tests) in the control cultures must not exceed 35%. Thus, the observed mean coefficient of variation in the control cultures during the experiment was 33.42%. Thirdly the coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 10%. Thus, the observed coefficient of variation of average specific growth rates during the experiment in control cultures was 8.26%. Hence, the test is considered valid as per OECD guideline, 201. Based on the growth inhibition of green alga Chlorella vulgaris by the test chemical 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole), the EC50 was determine to be 2.391 mg/l. Based on the EC50, it can be concluded that the chemical was toxic and can be consider to be classified as aquatic chronic 2 as per the CLP classification criteria.

 

 

Toxicity to microorganisms:

Various studies available for the test chemical were reviewed to determine the toxic nature of 2,2'-(ethene-1,2-diyldi-4,1-phenylene)bis(1,3-benzoxazole) (CAS no. 1533 -45 -5) on the growth of microorganisms. The studies are as mentioned below:

 

The comparatively quick and low cost bioassay with Photobacterium phosphoreum, strain NRRL-B-11177 to access the toxicity of test chemical to aquatic bacteria. The luminescent bacterial bioassay requires only a short period of time, i.e. minutes. In terms of testing a broad range of different chemicals with many different modes of action, a somewhat longer assay time, i.e. 30 min, is preferred, mainly to ascertain that potential diffusion problems are eliminated at source. Normally the pT values for a particular chemical rarely vary much with exposure time. The most commonly used operating conditions are 15°C for the EC50 tests with exposure times of 5 to 30 min. The pH of the test system can vary in the range of 5< pH <9 without great effect on the luminescence. The Effective Concentration causing 50% mortality of luminescent bacteria Photobacteria phosphereum was determine to be 3.35 mg/l after 30 minutes exposure with test chemical.

 

 

Similarly in the second study the comparatively quick and low cost bioassay with Photobacterium phosphoreum, strain NRRL-B-11177 to access the toxicity of test chemical to aquatic bacteria. The luminescent bacterial bioassay requires only a short period of time, i.e. minutes. In terms of testing a broad range of different chemicals with many different modes of action, a somewhat longer assay time, i.e. 30 min, is preferred, mainly to ascertain that potential diffusion problems are eliminated at source. Normally the pT values for a particular chemical rarely vary much with exposure time. The most commonly used operating conditions are 15°C for the EC50 tests with exposure times of 5 to 30 min. The pH of the test system can vary in the range of 5< pH <9 without great effect on the luminescence. The Effective Concentration causing 50% mortality of luminescent bacteria Photobacteria phosphereum was determine to be 5.43 mg/l and 6.83 mg/l after 30 minutes exposure with test chemical.

 

Thus based on the overall studies, it was concluded that the test chemical was toxic and the toxic concentration ranges from 3.35 mg/l to 6.83 mg/l.