2-methyl-m-phenylene diisocyanate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

The supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: Prediction is done using QSAR Toolbox version 3.4

Principles of method if other than guideline:

Prediction is done using QSAR Toolbox version 3.4

GLP compliance:

no

Specific details on test material used for the study:

- Name of test material (as cited in study report): Benzene, 1,3-diisocyanato-2-methyl-
- Molecular formula (if other than submission substance): C9H6N2O2
- Molecular weight (if other than submission substance): 174.1584 g/mol
- Smiles notation (if other than submission substance): Cc1c(N=C=O)cccc1N=C=O
- InChI:1S/C9H6N2O2/c1-7-8(10-5-12)3-2-4-9(7)11-6-13/h2-4H,1H3
- Substance type: Organic
- Physical state: Liquid

Analytical monitoring:

not specified

Details on sampling:

not specified

Vehicle:

not specified

Details on test solutions:

not specified

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

not specified

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Remarks on exposure duration:

not specified

Post exposure observation period:

not specified

Hardness:

not specified

Test temperature:

not specified

pH:

not specified

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

not specified

Details on test conditions:

not specified

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

37.121 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

not specified

Results with reference substance (positive control):

not specified

Reported statistics and error estimates:

not specified

The prediction was based on dataset comprised from the following descriptors: EC50
Estimation method: Takes average value from the 5 nearest neighbours
Domain  logical expression:Result: In Domain

((("a" or "b" or "c") and("d" and(not "e")) ) and("f" and "g") )

Domain logical expression index: "a"

Referential boundary:The target chemical should be classified as Acylation AND Acylation >> Isocyanates and Isothiocyanates AND Acylation >> Isocyanates and Isothiocyanates >> Isocyanates by DNA binding by OECD

Domain logical expression index: "b"

Referential boundary:The target chemical should be classified as Acylation AND Acylation >> (Tio)carbamoylation of protein nucleophiles AND Acylation >> (Tio)carbamoylation of protein nucleophiles >> Isothiocyanates, Isocyanates AND AN2 AND AN2 >> Direct carbamoylation of protein amines AND AN2 >> Direct carbamoylation of protein amines >> Isocyanates and Diisocyanates by Protein binding by OASIS v1.4

Domain logical expression index: "c"

Referential boundary:The target chemical should be classified as Acylation AND Acylation >> Isocyanates and Related Chemicals AND Acylation >> Isocyanates and Related Chemicals >> Isocyanates by Protein binding by OECD

Domain logical expression index: "d"

Referential boundary:The target chemical should be classified as Aromatic compound AND Isocyanate by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "e"

Referential boundary:The target chemical should be classified as Carbonic acid derivative OR CO2 derivative (general) OR Heterocyclic compound OR Sulfenic acid derivative by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "f"

Parametric boundary:The target chemical should have a value of log Kow which is >= 3.2

Domain logical expression index: "g"

Parametric boundary:The target chemical should have a value of log Kow which is <= 7.17

Validity criteria fulfilled:

not specified

Conclusions:

The median Effective concentration (EC50) value for 2,6-Toluene diisocyanate on Scenedesmus subspicatus in a 72 hour study was estimated to be 37.120 mg/L on the basis of effects on growth rate.

Executive summary:

72 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound 2,6-Toluene diisocyanate(CAS no. 91 -08 -7) and the result were predicted. The study was based on the effects of the test compound on Scenedesmus subspicatus in a static fresh watersystem. The predicted data suggests the effective concentration (EC50) for thetest compound 2,6-Toluene diisocyanate(CAS no. 91 -08 -7) was estimated to be 37.120 mg/l on the basis of growth rate.Thus, based on this value, it can be concluded that the test chemical 2,6-Toluene diisocyanate can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3 as per the CLP criteria.

Description of key information

72 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound 2,6-Toluene diisocyanate (CAS no. 91 -08 -7) and the result were predicted (SSS QSAR Prediction Model, 2016). The study was based on the effects of the test compound on Scenedesmus subspicatus in a static fresh watersystem. The predicted data suggests the effective concentration (EC50) for thetest compound 2,6-Toluene diisocyanate (CAS no. 91 -08 -7) was estimated to be 37.120 mg/l on the basis of growth rate. Thus, based on this value, it can be concluded that the test chemical 2,6-Toluene diisocyanate can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3 as per the CLP criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

37.12 mg/L

Additional information

Predicted data for the target chemical 2,6-Toluene diisocyanate (CAS No. 91-08-7) and the study for its read across substance were reviewed to summarize the following information:

 

72 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound 2,6-Toluene diisocyanate (CAS no. 91 -08 -7) and the result were predicted (SSS QSAR Prediction Model, 2016). The study was based on the effects of the test compound on Scenedesmus subspicatus in a static fresh watersystem. The predicted data suggests the effective concentration (EC50) for thetest compound 2,6-Toluene diisocyanate (CAS no. 91 -08 -7) was estimated to be 37.120 mg/l on the basis of growth rate. Thus, based on this value, it can be concluded that the test chemical 2,6-Toluene diisocyanate can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3 as per the CLP criteria.

 

Short term toxicity to Desmodesmus subspicatus (algae) study was carried out for 72 hrs (OECD SIDS INITIAL ASSESSMENT PROFILE, SIAM 23, 2006). The test organism Desmodesmus subspicatus was obtained from Institute of Plant Physiology, University of Göttingen. The study was based on the effects of the read across compound Isophorone diisocyanate on algae in a static fresh water system at a temperature of23 ± 2°C. Nominal substance conc. used for the study was1.1; 2.2; 4.4; 8.8; 17.5; 35; 70 mg/l, respectively.300 ml Erlenmeyer flasks with stoppers with 100 ml of test medium; light chamber with shaker was used as a test vessel. The study was performed at a pH of 8.0-8.1 at 0 hrs with a light intensity of 120 uE/m2 x s. Cell count was determined with microcellcounter Sysmex F-300 Digitana at every 24 hours. Blank Inoculum control was setup during the study. Blank inoculum control contains inoculum in nutrient medium and dilution water. After 2 days of undisturbed growth, cell counts suddenly stayed constant (17.5 mg/l nominal) or even dropped markedly (> 17.5 mg/l nominal) leading to an inhibition of growth rate of 8.3 % at 17.5 mg/l and higher concentrations compared to 0% inhibition at all lower concentrations. In total, however, EC50 values are beyond the highest test concentration based on both biomass (area under the growth curve) and growth rate. Based on effect on growth rate of algae, the 72 hr EC50, NOEC and LOEC value was determined to be >70, 4.4 and 8.8 mg/l, respectively. Thus, based on EC50 value, it can be concluded that the substance Isophorone diisocyanate can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3 as per the CLP criteria.

 

Short term toxicity to Scenedesmus subspicatus (algae)study was carried out for 72 hrs (OECD SIDS INITIAL ASSESSMENT PROFILE, 12th SIAM, 2001). The study was based on the effects of the read across compound 1,6-Hexamethylene diisocyanate on algae in a static fresh water system. Because of the rapid hydrolysis of test chemical, a water accommodated fraction (WAF) was prepared by direct weighing of 125 mg/l HDI into water. The test preparation was first stirred with an Ultra turrax for 60 sec/8000 rpm, then stirred for 24 hours with a magnetic stirrer and finally filtered. The resulting solution was analyzed to its TOC content and was used as a stock solution for further dilution steps. Based on effect on growth rate and biomass of Scenedesmus subspicatus, the 72 hr EC50 value was determined to be 77.4 mg/l and based on growth rate, the NOEC and LOEC value was determined to be 11.7 and 12.6 mg/l, respectively. Thus, based on EC50 value, it can be concluded that the substance1,6-Hexamethylene diisocyanate can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3 as per the CLP criteria.

 

Based on the overall reported results for target and its read across substance, it can be concluded that the test substance 2,6-Toluene diisocyanate can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 3 as per the CLP criteria.