2,4,6-triisopropyl-m-phenylene diisocyanate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP guideline study with acceptable restrictions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

m-tolylidene diisocyanate

EC Number:

247-722-4

EC Name:

m-tolylidene diisocyanate

Cas Number:

26471-62-5

Molecular formula:

C9H6N2O2

IUPAC Name:

Reaction mass of 2,4-Toluene diisocyanate and 2,6-Toluene diisocyanate

Constituent 2

Reference substance name:

4-methyl-m-phenylene diisocyanate

EC Number:

209-544-5

EC Name:

4-methyl-m-phenylene diisocyanate

Cas Number:

584-84-9

Molecular formula:

C9H6N2O2

IUPAC Name:

2,4-diisocyanato-1-methylbenzene

Constituent 3

Reference substance name:

2-methyl-m-phenylene diisocyanate

EC Number:

202-039-0

EC Name:

2-methyl-m-phenylene diisocyanate

Cas Number:

91-08-7

Molecular formula:

C9H6N2O2

IUPAC Name:

1,3-diisocyanato-2-methylbenzene

Test material form:

liquid

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
- Molecular formula: C9H6N2O2
- Molecular weight: 174.15 g/mol
- Smiles notation: CC(C)c1c(N=C(=O))c(C(C)C)c(N=C(=O))c(C(C)C)c1
- Substance type: aromatic diisocyanate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

No details available.

Test solutions

Vehicle:

not specified

Details on test solutions:

No details available.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

No further details available.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No post exposure observation period described.

Test conditions

Hardness:

No details available.

Test temperature:

No details available.

pH:

pH 7.37 - pH 7.85 (for tests conducted at initial pH 7.5)

Dissolved oxygen:

8.4 - 8.6 mg/L (for tests conducted at initial pH 7.5.)

Salinity:

Not applicable.

Nominal and measured concentrations:

No details available.

Details on test conditions:

Test substance was stirred into well water (adjusted to pH 7.5) at the desired concentrations, for 24 hours prior to addition of the daphnids. At this time, and also at the time of the test, the medium was analyzed for toluenediamines (TDA), dissolved organic carbon, pH and oxygen content. The experiment was conducted at initial pH 7.5. Additionally, the tests were repeated at initial pH 6 and 9.

Reference substance (positive control):

not required

Remarks:

Not required according to OECD 202.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

1.6 mg/L

Nominal / measured:

nominal

Remarks on result:

other: initial pH 7.5

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Remarks on result:

other: Initial pH 7.5

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

12.5 mg/L

Nominal / measured:

nominal

Remarks on result:

other: Initial pH 7.5

Effect concentrations 4

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.6 mg/L

Remarks on result:

other: initial pH 6

Effect concentrations 5

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

17.7 mg/L

Remarks on result:

other: initial pH 9

Details on results:

Due to the hydrolytic behaviour of TDI, the substance would have been predominantly hydrolyzed during this experiment. The initial test was carried out at pH 7.5, whereby a final total TDA concentration was measured as 5 mg/L. Under the same conditions the measured EC50(48h) was 4.3 mg/L for 80/20 TDA.

Results with reference substance (positive control):

Not applicable.

Reported statistics and error estimates:

95 % confidence internal: EC50 8.9-17.5 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Basic criteria were met.

Conclusions:

The study is regarded as a valid guideline study without GLP compliance. Since the read-across of m-tolyidene to 2,4,6-triisopropyl-m-phenylene diisocyanate is scienifically justified (please refer to the read-across statement), the reported EC50 value of 12.5 mg/L has to be taken into account to consider the substance as acutely toxic to freshwater water invertebrates.

Executive summary:

The acute toxicity of m-tolylidene diisocyanate to Daphnia magna was investigated according to OECD Guideline 202 (Tadokoro et.al., 1997). The main test was conducted with an initial pH of 7.5 and dissolved oxygen of 8.4 - 8.6 mg/L. The test duration was 48 hours, resulting in an EC50 value of 12.5 mg/L. A final total TDA concentration of 5 mg/L was measured, which was expected before, due to the hydrolytic behaviour of TDI. Furthermore, the test was carried out at initial pH values of 6 and 9, resulting in EC50 values of 1.6 mg/L and 17.7 mg/L, respectively.