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Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Short-term toxicity to fish

The short term toxicity on fish was predicted for test substance 2-hydroxy-1H-isoindole-1,3(2H)-dione (CAS: 524-38-9) using the EPI Suite ECOSAR version 1.10. On the basis of effects observed in a static freshwater system, the lethal concentration LC50 value for the substance is estimated to be 6297.041mg/l for fish for 96 h duration. Based on this value, it can be concluded that the test chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione can be considered as non toxic to fish at predicted concentrations and can be considered to be not classified as per the criteria mentioned in CLP regulation.

Short term toxicity to aquatic invertebrates

Based on the prediction done using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic invertebrates was predicted for2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS: 524-38-9). EC50 value was estimated to be 161.94 mg/l for Daphnia magna for 48 hrs duration.

Toxicity to aquatic algae and cyanobacteria

Based on the prediction done using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 2-hydroxy-1H-isoindole-1,3(2H)-dione

 (CAS no. 524 -38 -9). EC50 value was estimated to be 109.15 mg/l for Pseudokirchneriella subcapitata for 72 h duration. Based on this value it can be concluded that the substance 2-hydroxy-1H-isoindole-1,3(2H)-dione is considered to be non-toxic to aquatic environment and can be considered to be not classified as per the CLP classification criteria.

 

Additional information

Short-term toxicity to fish

Four studies including experimental data and predicted report from reliable models for short term fish toxicity endpoint of test chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione (Cas no. 524-38-9) with relevant read across chemicals which are structurally similar to target chemical were summarized as follows:

First prediction using EPI Suite ECOSAR version 1.10 model, for target chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione (CAS: 524-38-9) wherein the short term toxicity on fish was estimated on the basis of effects in a static freshwater system. The lethal concentration LC50 value for the substance was estimated to be 6297.041mg/l for fish for 96 h duration. Based on this value, it can be concluded that the test chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione can be considered as non toxic to fish at predicted concentrations and can be considered to be not classified as per the criteria mentioned in CLP regulation.

Above result is supported by experimental study for read across chemical Phthalimide i.e 1H-isoindole-1,3(2H)-dione (Cas no. 85-41-6). The acute toxicity test of Phthalimide to Oryzias latipes was conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test) at the dose concentration- control, 55.6 mg/L, 100.0 mg/L (nominal concentrations) at 24±1 degreeC test temp., 6.6 - 7.1 pH and 5.1 - 11.0 mg/l (Saturated concentration at 24°C is 8.25 mg/l) dissolved oxygen in semi static freshwater condition for 96 hrs. During experiment the lethal concentration (LC50) was determined to be 100 mg/l with 95% confidence limit of 55.6 ->100 mg/l. Thus it is concluded that the test substance Phthalimide is non toxic to fish and thus not consider for the aquatic classification as per the CLP criteria. (Japan chemicals collborative knowledge database (J-check); 2017)

Data for the same read across (Phthalimide i.e 1H-isoindole-1,3(2H)-dione (Cas no. 85-41-6)) from different source (Spec.Sci.Rep.Fish.No.207, Fish Wildl.Serv., U.S.D.I., Washington, DC:157 p.) indicated that a short term toxicity study to Petromyzon marinus was carried out for 24 hrs. Test was performed under static conditions. After exposure to test animal at dose conc.5 mg/l of test chemical Phthalimide, no mortality effects were observed on fish. Thus, the NOEC value was considered to be 5 mg/l.

A supporting study from authorative data source (HPVIS) of another read across chemical N-Methylphthalimide (2-methyl-1H-isoindole-1,3(2H)-dione-Cas no. 550-44-7) was also reviewed. The acute fish toxicity study conducted according to OECD guideline 203 for chemical N-Methylphthalimide (2-methyl-1H-isoindole-1,3(2H)-dione) on fish species Rainbow trout (Oncorhynchus mykiss). The Rainbow Trout Mortalities (LC50) after a 24, 48, 72 and 96-h exposure to N-Methylphthalimide (2-methyl-1H-isoindole-1,3(2H)-dione) were reported as -

LC50 (48 , 72 and 96h) 110 mg/L (95% CI = 93 - 131 mg/L)

LC50 (24h) 125 mg/L (95% CI = 111 - 140 mg/L)

Thus based on the all available results for acute fish toxicity, it can be considered that the test chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione (Cas no. 524-38-9) is non toxic to fish at environmentally relevant concentrations and can be considered to be not classified as per the criteria mentioned in CLP regulation.

Short term toxicity to aquatic invertebrates

Short term toxicity to aquatic invertebrates for2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS: 524-38-9) was summaries with two predicted data and two experimental studies of two read across substances are as follows:

Based on the prediction done using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic invertebrates was predicted for2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS: 524-38-9). EC50 value was estimated to be 161.94 mg/l for Daphnia magna for 48 hrs duration.

In another prediction done by EPI suite, ECOSAR version 1.1, the LC 50 value for short term toxicity to aquatic invertebrates was predicted. The LC50 value for short term toxicity to aquatic invertebrates was predicted to be 3010.80 mg/l for 2-hydroxy-1H-isoindole-1,3(2H)-dione in 48 hrs. Based on this value it can be concluded that the substance is considered to be not toxic to aquatic environment and can be considered to be not classified as per the criteria mentioned in CLP regulation.

 

Short term toxicity to aquatic invertebrates was performed for read across 1H-isoindole-1,3(2H)-dione (85-41-6) [J-check, 2010] which was 60-70 % structurally similar with target. The test was performed in Daphnia magna for 48 hrs in static fresh water system. The concentration ranges from 3.7, 6.7, 12.0, 21.6, 38.9, 70.0 mg/L along with control. Number of organisms per vessel was 20 per concentration i.e 5 per vessel. 16 hours light and 8 hour dark was the applied photoperiod. On the basis of experiment, the EC 50 value for 1H-isoindole-1,3(2H)-dione (85-41-6) was determined to be 20.8 mg/l. Based on the value the substance was considered to be toxic to aquatic invertebrates but as it was readily biodegradable, hence the 1H-isoindole-1,3(2H)-dione was considered to be not classified based on the CLP regulations.

 

For another read across N-Methylphthalimide (550-44-7) [HPVIS Robust summary, 2002] which was 80-90 % structurally similar with target , the test was performed in Daphnia magna for 24 hrs in static test condition. Nominal and measured test concentrations were used, in which the nominal concentration were used for test. The culture vessels were incubated in a temperature controlled room at 20 + 1ºC, under an 8-hour dark and 16-hour light photoperiod. The light intensity at the water surface was 400 to 800 lux. Daphnia in stock culture were fed with green alga and solution of yeast. At test initiation, dissolved oxygen, temperature, pH, and conductivity ranged from 8.3 to 9.1 mg/L, 19.5 to 20.7 ºC, 6.7 to 7.9 units, and 342 to 348 μS/cm respectively. At test termination, dissolved oxygen, temperature, and pH ranged from 8.3 to 9.1 mg/L, 19.5 to 20.7 ºC, and 7.0 to 7.7 units, respectively. General observations on behavior were made at test initiation, and at 30 minutes and 24 hours of exposure. Based on experimental result, the EC50 value for 24 hrs of N-Methylphthalimide (550-44-7) was determined to be 112 mg/l.

Based on the above predicted data and studies of read across chemicals it can be considered that all the above studies supported the target classification, so based on the results it was considered that all weight of evidences supported the classifications and2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS: 524-38-9) was considered to be non-toxic to aquatic invertebrates andcan be concluded to be not-classified as per the CLP regulations.

Toxicity to aquatic algae and cyanobacteria

Various predicted data for the target chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione (CAS No. 524-38-9) and weight of evidence study for its read across substancewere reviewed to summarize the following information:

Short term toxicity on aquatic algae and cyanobacteria of target chemical2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS No. 524-38-9) is predicted using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances (2017).EC50 value was estimated to be 109.15 mg/l for Pseudokirchneriella subcapitata for 72 h duration. Based on this value it can be concluded that the substance 2-hydroxy-1H-isoindole-1,3(2H)-dione is considered to be non-toxic to aquatic environment and can be considered to be not classified as per the CLP classification criteria.

 

In another prediction done using the EPI Suite ECOSAR version 1.10 (EPI Suite, 2017), the short term toxicity on green algae was predicted for test substance2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS No. 524-38-9).On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 1101.824 mg/l for green algae for 96 hr duration. Based on this value, it can be concluded that the test chemical 2 -hydroxy-1H-isoindole-1,3(2H)-dione can be considered as non-toxic to green algae at environmentally relevant concentrations and can be considered not-classified as per the CLP classification criteria.

 

In a weight of evidencestudy from authoritative database (J-CHECK, 2016) of the read across chemicalPhthalimide(CAS no. 85-41-6),short term toxicity to algae study was carried out for 72 hrs for evaluating the effects of the test compound Phthalimide on green algae in a static fresh water system. On the basis of effect on growth rate of the test organism green algae, the 72 hr EC50 and NOEC value was determined to be > 150 and 1.1 mg/l and on the basis of areas under the growth curves, the 72 hr EC50 and NOEC value was determined to be 62 and 6.5 mg/l, respectively. Thus, based on the EC50 value (> 150 mg/l), it can be concluded that the substance Phthalimide can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

 

For the same read across chemical Phthalimide(CAS no. 85-41-6),short term toxicity to Selenastrum capricornutum study was carried out for 72 hrs (OECD SIDS, 2005). The study was performed according to OECD Guideline 201 (Alga, Growth Inhibition Test). The study was based on the effects of the read across compound Phthalimide on Selenastrum capricornutum in a static fresh water system at an average temperature of 22.1°C. Test chemical conc. used for the study were 0, 10.6, 19.1, 34.3, 61.7, 111.1 and 200.0 mg/l, respectively. 300 mL net triangle conical glass flask was used as a test vessel. The flasks were incubated in a shaking water bath at 22.1 degrees C with continuous illumination at 4000 - 5000 lux. Based on the effect on growth rate of the test organism Selenastrum capricornutum, the 72 hrs ErC50 and NOEC value was determined to be 161 and 10.7 mg/l, respectively. Thus, based on EC50 value, it can be concluded that the substance Phthalimide can be considered as non-toxic to aquatic organisms and thus cannot be classifiedas hazardous as per the CLP criteria.

 

In an another weight of evidence study for read across chemical N-(Cyclohexylthio)phthalimide (CAS no. 17796-82-6) (HSDB and High Production Volume (HPV) Challenge Program; 2016), short term toxicity to Selenastrum capricornutum (green algae) study was carried out for 96 hrs. The study was based on the effects of the read across compound N-(Cyclohexylthio)phthalimide on Selenastrum capricornutum (green algae) in a static fresh water system. The test algae were obtained from the US EPA Environmental Research Laboratory in Corvallis, Oregon. Test chemical conc. used for the study were 0, 6, 10, 32, 56 and 100 mg/l, respectively. Initial cell density of algae was 2 × 104cells/ml. All tests were carried out in triplicates. Statistical analysis involved converting each test concentration to a logarithm, and the corresponding percentage decrease of in vivo chlorophyll a or cell numbers was converted to a probit. The EC50 and 95% confidence limits were then calculated by linear regression. The toxicity of the test substance to algae was similar throughout the 96 hr exposure. There was no significant difference between growth of the control and solvent control cultures after 96 hr of exposure by either measured parameter. Based on effect on biomass and growth of the test organism Selenastrum capricornutum (green algae), the 96 hr EC50 value was determined to be 21 mg/l and on the basis of chlorophyll measurement, the 96 hr EC50 value was determined to be 22 mg/l and NOEC value was 6 mg/l, respectively. Thus, based on the EC50 value, it can be concluded that the substance N-(Cyclohexylthio)phthalimide can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3. Since the chemical is readily biodegradable in nature, chemical N-(Cyclohexylthio)phthalimide can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

 

Thus, based on the overall reported results for target chemical2-hydroxy-1H-isoindole-1,3(2H)-dione(OECD QSAR toolbox version 3.4 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, HSDB andsecondary sourceHigh Production Volume (HPV) Challenge Program; 2016), it can be concluded that the test substance2-hydroxy-1H-isoindole-1,3(2H)-dionecan be considered asnon-toxic to aquatic environment and can be considered to be not classified as per the CLP classification criteria.