p-(trifluoromethoxy)phenyl isocyanate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

Test procedure in accordance with national standard methods with acceptable restrictions. Isocyanates are known to rapidly hydrolyse under the formation of the corresponding amine as well as solid polyurea compounds *. However, the insoluble inert polyurea is not assumed to cause environmental hazards due to the reduced uptake of high molecular mass compounds, whereas the amine is assumed to be the ecotoxicological relevant species. Concluding, tests performed using the corresponding amine can equally be used to assess the ecotoxicological hazards of isocyanates assuming the complete transfer of the isocyanate into the corresponding amine while neglecting the formation of a certain fraction ecotoxicological not active polyurea compounds. An underestimation of environmental hazards is thus avoided supporting a conservative and thus protective hazard assessment. * Bayer Industry Services (2004). 4-chlorophenyl-isocyanate: Investigation on Stability in Aqueous Test Solutions. Project No: 200300181. Leverkusen, Germany. Bayer Industry Services (2003). Isopropylisocyante: Investigation on Stability in Aqueous Test Solutions. Project No: 200300095. Leverkusen, Germany.

Qualifier:

equivalent or similar to guideline

Guideline:

other: EG Richtlinie 79/831 EWG Anhang V

Deviations:

yes

Remarks:

according to EEC Directive 79/831 (Painter)

GLP compliance:

no

Specific details on test material used for the study:

For the registered substance 4-trifluoromethoxy phenyl isocyanate (CAS No. 35037-73-1), the water molecules will react with free isocyanate groups to generate carbon dioxide and primary amines which forms 4-trifluoromethoxy aniline (CAS No. 461-82-5), that is a hydrolysis product of 4- trifluoromethoxy phenyl isocyanate. Thus, in this endpoint the hydrolysis product is tested. For details of hydrolysis process please refer to section 13 "expert statement".

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

aniline

Test performance:

Oxygen consumption was measured daily using a sapromat.

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

Conc.: 100 mg/mL 4-Trifluormethoxyanilin
0% degradation after 28d
Isocyanates are known to rapidly hydrolyse under the formation of the corresponding amine as well as solid polyurea compounds *. However, the insoluble inert polyurea is not assumed to cause environmental hazards due to the reduced uptake of high molecular mass compounds, whereas the amine is assumed to be the ecotoxicological relevant species. Concluding, tests performed using the corresponding amine can equally be used to assess the ecotoxicological hazards of isocyanates assuming the complete transfer of the isocyanate into the corresponding amine while neglecting the formation of a certain fraction ecotoxicological not active polyurea compounds. An underestimation of environmental hazards is thus avoided supporting a conservative and thus protective hazard assessment.
* Bayer Industry Services (2004). 4-chlorophenyl-isocyanate: Investigation on Stability in Aqueous Test Solutions. Project No: 200300181. Leverkusen, Germany.
Bayer Industry Services (2003). Isopropylisocyante: Investigation on Stability in Aqueous Test Solutions. Project No: 200300095. Leverkusen, Germany.

The results of the corresponing amine (p-Trifluormethoxyanilin, 461-82-5) were taken because the test substance TFMOPI (CAS no. 35037 -73 -1) hydrolyses rapidly.

Interpretation of results:

not readily biodegradable

Conclusions:

100 mg/mL of 4-Trifluormethoxyaniline was used. 0% degradation after 28 days.

Executive summary:

The results of the corresponing amine (p-Trifluormethoxyanilin, 461-82-5) were taken because the test substance TFMOPI (CAS no. 35037 -73 -1) hydrolyses rapidly. 100 mg/mL of 4-Trifluormethoxyaniline was used. 0% degradation after 28 days.

Description of key information

Biodegradation of m-Trifluormethoxyaniline in water, the corresponding amine of 4-Trifluormethoxyphenylisocyanate, was not observed in this study.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

Isocyanates are known to rapidly hydrolyse under the formation of the corresponding amine as well as solid polyurea compounds *. However, the insoluble inert polyurea is not assumed to cause environmental hazards due to the reduced uptake of high molecular mass compounds, whereas the amine is assumed to be the ecotoxicological relevant species. Concluding, tests performed using the corresponding amine can equally be used to assess the ecotoxicological hazards of isocyanates assuming the complete transfer of the isocyanate into the corresponding amine while neglecting the formation of a certain fraction ecotoxicological not active polyurea compounds. An underestimation of environmental hazards is thus avoided supporting a conservative and thus protective hazard assessment.

* Bayer Industry Services (2004). 4-chlorophenyl-isocyanate: Investigation on Stability in Aqueous Test Solutions. Project No: 200300181. Leverkusen, Germany.

Bayer Industry Services (2003). Isopropylisocyante: Investigation on Stability in Aqueous Test Solutions. Project No: 200300095. Leverkusen, Germany.