7-(diethylamino)-4-methyl-2-benzopyrone

Endpoint summary

Description of key information

Short term toxicity to fish:

Short term toxicity to fish was conducted for 96 hrs for assessing the effect of test chemical. The test was performed in accordance to OECD guideline No. 203 “Fish Acute Toxicity Test”. Zebra fish (Danio rerio) of average weight 0.1899 g and average length of 1.63 cm was used as a test organism for the study. Test fishes were kept in a static tank in tap water passed through reverse osmosis system, under natural conditions along with proper feed and aeration. During the housing period, test fishes were fed once daily with standard brand fed. The test conditions during the housing of the test organisms were oxygen content of 8.0 mg/l, pH 7.54, water temperature 23.5°C and under a photoperiod of 16:8 hr light: dark conditions, respectively. A limit test was performed at a concentration of 10 mg/l (nominal concentrations). Total 8 fishes were exposed to test chemical in a 5 lit bowl aquaria containing 4 liters of potable water. The test vessels were placed in a room at a temperature of 23.6°C, pH 7.05, hardness of water 148.5 mg of CaCO3 and under a photoperiod of 16:8 hr light: dark conditions, respectively. Aeration in test vessels was provided 1 day before the start of the experiment. No mortalities were observed in the control and test vessel. On the basis of effect of test chemical on mortality of the test organism, the 96 hr LC0 and median lethal concentration (LC50 (96 h)) was determined to be 10 and > 10 mg/l. Based on the LC50 value, it can be concluded that the substance is likely to be hazardous to aquatic invertebrate and considered to be classified as aquatic chronic 3 category as per the CLP classification criteria.

Short-term toxicity to aquatic invertebrates:

Study was condcuted to determine effective concentration of test chemical. Based on the immobilisation of daphnia magna due to the exposure of chemical  for 48 hrs, the median effective concentration EC50 was determine to be 10.9 mg/l.

Short-term toxicity to aquatic algae:

Based on the growth rate inhibition of algae Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) due to the exposure of chemical the ErC50 was determine to be 17.5 mg/l.

Toxicity to microorganism:

Study was conducted to determine effect of test chemical on micro-organism. The test chemical is showed varied value on microorganism  in the concentration range of  0.18 -100 mg/l

Additional information

Short term toxicity to fish:

Following different studies includes experimental study for the target chemical and read-across analogues which is extracted by using mechanistic approach and functionally and structurally similar to the target chemical to observe the toxicity of test chemical on fish.

Short term toxicity to fish was conducted for 96 hrs for assessing the effect of test chemical. The test was performed in accordance to OECD guideline No. 203 “Fish Acute Toxicity Test”. Zebra fish (Danio rerio) of average weight 0.1899 g and average length of 1.63 cm was used as a test organism for the study. Test fishes were kept in a static tank in tap water passed through reverse osmosis system, under natural conditions along with proper feed and aeration. During the housing period, test fishes were fed once daily with standard brand fed. The test conditions during the housing of the test organisms were oxygen content of 8.0 mg/l, pH 7.54, water temperature 23.5°C and under a photoperiod of 16:8 hr light: dark conditions, respectively. A limit test was performed at a concentration of 10 mg/l (nominal concentrations). Total 8 fishes were exposed to test chemical in a 5 lit bowl aquaria containing 4 liters of potable water. The test vessels were placed in a room at a temperature of 23.6°C, pH 7.05, hardness of water 148.5 mg of CaCO3 and under a photoperiod of 16:8 hr light: dark conditions, respectively. Aeration in test vessels was provided 1 day before the start of the experiment. No mortalities were observed in the control and test vessel. On the basis of effect of test chemical on mortality of the test organism, the 96 hr LC0 and median lethal concentration (LC50 (96 h)) was determined to be 10 and > 10 mg/l. Based on the LC50 value, it can be concluded that the substance is likely to be hazardous to aquatic invertebrate and considered to be classified as aquatic chronic 3 category as per the CLP classification criteria.

Second short term fish toxicity study was conducted for 24 hrs for assessing the lethal effect of read across chemical on test organism. Study was conducted in a static system at 18°C and 7.2 pH. Test was perfomed on Ptychocheilus oregonensis as a test organism.On the basis of effect of test chemical on test organism,the 48 hrs LC50 value was determined to be 10mg/l.

Last short term fish toxicity study was conducted for 24 hrs for assessing the lethal effect of read across chemical on test organism. Study was conducted in a static system at 10°C and 7.2 pH. Test was perfomed on Ptychocheilus oregonensis used as a test organism. On the basis of effect of test chemical on test organism, the 24 hrs LC50 value was determined to be 10mg/l.

On the basis of the above results, it can be concluded that the test chemical was considered to be toxic to aquatic fishes and hence, considered to be classified in 'aquatic chronic category 3' as per the CLP classification criteria.

Short-term toxicity to aquatic invertebrates:

Following different studies includes experimental study for the target chemical and read-across analogues which is extracted by using mechanistic approach and functionally and structurally similar to the target chemical to observe the toxicity to test chemical on aquatic invertebrates.

Aim of the first study was to assess the short term toxicity of test material to aquatic invertebrates 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 solution 100 g/l was prepared by dissolving white powder in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with reconstituted test water. Acetone used as a solvent because of limited solubility of tested sample in water. 0, 0, 0.5, 1, 2, 4, 8, 16 mg/l nominal 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 test substance in Daphnia magna was determined to be10.9 mg/L with the confidence interval of 9.9 - 11.9 mg/l on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, it can be concluded that the substance is likely to be hazardous to aquatic invertebrate and can be consider to be classified as aquatic chronic 3 category as per the CLP classification criteria.

Second short term toxicity to aquatic Invertebrate study was conducted for 48hrs for assessing the effect of read across chemicalon test organism. 24 h old Daphnia magna(Water flea) was used as a test organism for the study. Thus, effect of test chemical on mortality of the test organismDaphnia magna, the 48 hr LC50 was determined to be ranges from 10 -18 mg/l .Based on the LC50 value, chemical can be considered as toxic to aquatic invertebrates and can be classified as ‘’category chronic-3’’ as per CLP classification criteria.

 

Last short term toxicity to aquatic Invertebrate study was conducted for 48hrs for assessing the effect of read across chemical on test organism at 20°C. Based on effect of test chemical on mortality of the test organism Daphnia magna, the 48 hr NOEC value was determined to be 16.017 mg/l..

Based on the effect of test chemical on test organism, chemical can be considered as toxic to aquatic invertebrates and can be classified as ‘’category chronic-3’’ as per CLP classification criteria.

Toxicity to aquatic algae:

Various short term studies available for the test chemical and read-across chemical were reviewed to determine the toxic nature of test chemical on the growth of algae. The studies are as mentioned below

 

Objective of this experimental key study was to observe the action of test chemical when it exposed with the 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 mg/l was prepared by dissolving white powder in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. 0, 0, 6, 12, 24, 50 and 100 mg/l nominal concentration 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, the ErC50 was determine to be 17.5 mg/l. Based on the ErC50 value, it can be conclude that the substance is likely to be hazardous to aquatic algae and classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Above study was supported by the second study from experimental report the effect of test chemical was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 2.63 mg/L,3.95 mg/L,5.92 mg/L,8.88 mg/L,13.33 mg/L,20 mg/L. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be 10.560 mg/L. Thus based on this value, it can be concluded that the substance can be considered as toxic to aquatic organisms and thus can be classified in aquatic chronic category 3 as per the CLP classification criteria.

Above study supported by read-across chemical, toxicity to green algae study was carried out for assessing the effect of the test chemical at 22°C. The study was conducted for 48 hrs. For the test chemical, based on effect on growth rate of the test organism, the 48hr LOEC was determined to be  32mg/l.

 

Thus on the basis of both experimental study reports, it was concluded that the test chemical exhibit toxicity to aquatic algae and classified in aquatic chronic category 3 as per the CLP classification criteria.

Toxicity to microorganism:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the toxicity of microorganism of the test chemical .The studies are as mentioned below:

A screening method based on the measurement of the respiration rate of activated sludge for assessing the possible inhibitory effect of dyestuffs on aerobic waste-water bacteria. The test principle involves measuring the respiration rate of an activated sludge and comparing it with the respiration rate of the same activated sludge under identical conditions, but in the presence of the chemical under test. The test was carried out in activated sludge respiration rate apparatus with constant 20 ± 2°C and pH about 7-8. The test concentration used was 100 mg/l. OECD recommended synthetic sewage was used as feed, while activated sludge was obtained from a sewage works treating predominantly domestic sewage or from a sewage works treating predominantly industrial waste water. The respiration rate of an activated sludge and the respiration rate of activated sludge with test chemical were noted down. In order to calculate the inhibitory effect of a particular chemical at 100 mg/l test concentration its respiration rate is expressed as a percentage of the mean of the two control respiration rates. For those chemicals whose respiration rate is at least 80% of the control, the IC50 (concentration for 50% inhibition of respiration rate) is recorded as >100 mg/l.

Thus, IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical on activated sludge (aerobic bacteria) is determined to be >100 mg/1 after 3 hrs of exposure.

The study was conducted to evaluate the toxic effects of the test chemical on the microorganism Tetrahynema pyriformis. The test was conducted for the period of 40-h in static conditions. Five different concentrations were taken to evaluate the ICG 5, median inhibition growth concentration. Test was conducted in the replicates and the growth inhibition was recorded using spectrophotometrically.Based on the results obtained from the experiment the ICG 50 was determined as 0.18 mg/L.The test chemical is showed varied value on microorganism  in the concentration range of  0.18 -100 mg/l