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

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

7.42 µg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

7.42 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.742 µg/L

Assessment factor:

100

Extrapolation method:

assessment factor

PNEC marine water (intermittent releases):

0.742 µg/L

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

100 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

400.2 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

40.02 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

79.8 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.24 mg/kg food

Assessment factor:

3 000

Additional information

No hazard to the environment has been determined for the registered substance in any acute or chronic ecotoxicological study available to date. Due to the fast hydrolysis (DT50 = 37s, Neuland 2020) and the poor water solubility (0.005414 mg/L, WSKOW 2012), which could not be determined experimentally thereby, the preparation of test solutions with TRIDI was very difficult. As recommended in the OECD Guidance Document No. 23 on aqueous phase aquatic toxicity testing of difficult test chemicals (second edition, February 2019) solubility pre-experiments including analytical dose verification were performed before initiation of any aquatic toxicity testing to determine the maximum dissolved concentration that can be achieved in the specific test solution under test conditions. In the long-term studies, the maintenance and reproducibility of test medium concentrations could only be achieved by the use of the solvent DMF, which limited the concentration of the test solutions. It can therefore be concluded that no effects have been determined up to the "water solubility" of the test substance or rather the highest possible concentration of the test substance in water. Hence, it is expected that the test substance poses no hazard to the environment based on the available data.

Conclusion on classification

Considering all available data on short- and long-term toxicity to aquatic organisms and taking into account the poor water solubility of the registered substance (0.005141 mg/L at 25°C calculated by KOWWIN), no acute or chronic hazard was determined for the aquatic environment up to and clearly above the limit of solubility or relevant limit concentrations, whichever is the lowest. Furthermore rapid degradation from the environment is proven by the fast hydrolysis ((DT50= 37s, Neuland 2020). Hence, no acute or chronic hazard was determined for the aquatic environment and the substance does not need to be classified according to Regulation (EC) No 1272/2008.

Due to the rapid hydrolysis of the registered substance and due to the design and duration of the aquatic studies conducted, the determination of the toxicity of the degradation products was automatically included. Confirmation of this is provided by the analytical measurements for dose verification accompanying the long-term studies, for which the sum of TRIDI and the main hydrolysis product TRIDA was determined. Since neither an acute nor a chronic effect was determined in the available aquatic studies for all trophic levels up to the solubility limit or relevant limit concentrations, an acute or chronic toxicity of the degradation products in the relevant concentrations can also be excluded. Furthermore, the results of the available bioaccumulation study with the main hydrolysis product TRIDA (Gourlay, 2021) confirm, that there is no potential for bioaccumulation.