1,3-bis(1-isocyanato-1-methylethyl)benzene

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Nov. 01, 1984 to April 24, 1985

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

Deviations:

no

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: Once in 2 week (2 fish from each tank)
- Sampling intervals/frequency for test medium samples: Twice a week for 8 weeks
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):
Sample preparation: Test chemical (0.1 g) was dissolved in purified water and pretreated to prepare a standard solution of 5 or 10 µg/mL for test media or test fish analysis, respectively.
Analytical method: HPLC

Vehicle:

yes

Details on preparation of test solutions, spiked fish food or sediment:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Dissolved in water and pretreated before HPLC analysis
- Chemical name of vehicle: Water
- Concentration of vehicle in test medium:
Stock solution: Test chemical (0.1 g) was dissolved in deionized water to prepare a stock solution of 20 or 200 mg/mL
Standard solution: Test chemical (0.1 g) was dissolved in purified water and pretreated to prepare a standard solution of 5 or 10 µg/mL for test media or test fish analysis, respectively

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Strain: Cyprinus carpio
- Source: Kitamura Fish Farm at Yatsushiro-shi, Kumamoto, Japan
- Length at study initiation (length definition, mean, range and SD): 9.4 cm
- Weight at study initiation (mean and range, SD): 21.5 g
- Description of housing/holding area: Temperature controlled continuous flowthrough system (Aquatron)
- Feeding during test
- Food type: Fish feed (Nippon Haigoshiryo Co., Ltd.)
- Amount: Approximately 2 % of fish weight
- Frequency: Twice a day


ACCLIMATION
- Acclimation period: 14 d at 25 °C

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

8 wk

Hardness:

No data

Test temperature:

25 ± 2 °C

pH:

No data

Dissolved oxygen:

6.5-7.4 mg/L

TOC:

No data

Salinity:

No data

Details on test conditions:

TEST SYSTEM
- Type: Open
- Material, size, headspace, fill volume: Glass tank of 100 L capacity
- Renewal rate of test solution (frequency/flow rate): Flow rate: 1158 L/d
- No. of organisms per vessel: 20 fish/tank (at the start of the test)


TEST MEDIUM / WATER PARAMETERS
- Intervals of water quality measurement: Twice a week

Nominal and measured concentrations:

0.1 and 1 mg/L

Reference substance (positive control):

no

Details on estimation of bioconcentration:

No data

Key result

Conc. / dose:

0.1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

ca. 1.2 - <= 2.7 dimensionless

Time of plateau:

8 wk

Remarks on result:

other: No abnormality in behaviour and appearance of fish were observed.

Key result

Conc. / dose:

1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

>= 1 - <= 5.7 dimensionless

Time of plateau:

8 wk

Remarks on result:

other: No abnormality in behaviour and appearance of fish were observed

Details on kinetic parameters:

Not applicable

Metabolites:

Not applicable

Results with reference substance (positive control):

Not applicable

Details on results:

Not applicable

Reported statistics:

Not applicable

Table 1. Measured concentration of test material in test media (mg/L)

 

	Wk 2	Wk 4	Wk 6	Wk 8
Level 1	0.966	0.957	0.954	0.952
Level 2	0.0912	0.0917	0.0910	0.0902

 

Table 2. Bioconcentration Factor

 

	Wk 2	Wk 4	Wk 6	Wk 8
Level 1	1.6 1.0	1.5 3.8	5.7 3.7	3.7 4.6
Level 2	<1.2 <1.2	<1.2 <1.2	<1.2 2.7	<1.2 <1.2

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the BCF of the test substance was found to be in the range of <1.2 - 2.7 at 0.1 mg/L and 1.0 - 5.7 at 1.0 mg/L.

Executive summary:

A study was performed to assess the Bioconcentration Factor (BCF) of the test substance in carp according to OECD Guideline 305 C under flow-through conditions.Cyprinus carpio(20/tank) were exposed at concentrations of 0.1 and 1.0 mg/L for 8 weeks at 25 ± 2°C. The concentrations of the substance in test media and fish were analysed by HPLC. BCFs were calculated at 2, 4, 6 and 8 weeks of exposure. No abnormalities in behaviour or appearance were observed. BCFs reached plateaus after 8 weeks and no significant differences were found between the BCFs at the two exposure levels. Under the study conditions, the BCF of the test substance was found to be in the range of <1.2 - 2.7 at 0.1 mg/L and 1.0 - 5.7 at 1.0 mg/L (Sudo, 1985).

Key value for chemical safety assessment

BCF (aquatic species):

5.7 dimensionless

Additional information

A study was performed to assess the Bioconcentration Factor (BCF) of the test substance in carp according to OECD Guideline 305 C.Cyprinus carpio (20/tank) were exposed at concentrations of 0.1 and 1.0 mg/L for 8 weeks at 25 ± 2°C. The concentrations of the substance in test media and fish were analysed by HPLC. BCFs were calculated at 2, 4, 6 and 8 weeks of exposure. No abnormalities in behaviour or appearance were observed. BCFs reached plateaus after 8 weeks and no significant differences were found between the BCFs at the two exposure levels. Under the study conditions, the BCF of the test substance was found to be in the range of <1.2 - 2.7 at 0.1 mg/L and 1.0 - 5.7 at 1.0 mg/L (Sudo, 1985).

As discussed in Section 4.1.1, m-TMXDI hydrolyses rapidly in water to an insoluble urea and/or polyurea, as well as potentially to tetramethyl-m-xylylene diamine. Therefore, the substance is not bioavailable as such in significant amounts for uptake by aquatic organisms. Furthermore, a log Kow of 3.53 and 1.89 were predicted for the urea and tetramethyl-m-xylylene diamine respectively, using the model KOWWIN (2000), indicating that the bioaccumulation potential of these hydrolysis products is low (Environment Canada/Health Canada, 2008).

Overall, the weight of evidence suggests that neither m-TMXDI nor its degradation products will bioaccumulate in aquatic organisms.

References

Environment Canada/Health(2008). Screening assessment for the challenge. Benzene, 1,3-bis(1-isocyanato-1-methylethyl)-(tetramethyl-m-xylylene diisocyanate). Chemical Abstracts Service Registry Number 2778-42-9. https://www.ec.gc.ca/ese-ees/9C2F9934-38D3-4940-A472-5DD238B6076D/batch2_2778-42-9_en.pdf.