3,4-dichlorophenyl isocyanate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

peer reviewed data cited in EU risk assessment report

Justification for type of information:

Due to insufficient reporting of the experimental details, this study was rated with a Klimisch score of 4 (‘not assignable’). As none of the available studies can serve as a key study with a sufficiently detailed reporting justifying a Klimisch score of 1 or 2 for the given endpoint, several independent sources were used in a weight of evidence approach. ‘Using weight of evidence implies that no single study of sufficient quality and reliability exists, and that information from several independent sources is required to be able to reach a conclusion on a particular property of the substance.' (guidance document How to prepare registration and PPORD dossiers, p. 87)
For further details on the justification for the use of data on the hydrolysis product 3,4-dichloroaniline please refer to chapter 13.2.

Qualifier:

according to guideline

Guideline:

ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)

GLP compliance:

not specified

Specific details on test material used for the study:

The hydrolysis of 3,4-dichlorophenyl isocyanate is expected to occur faster than within 12 h (Please refer to the expert statement in section 13.) Thus, it is technically not feasible to conduct toxicity tests towards the aquatic species with the test item 3,4-dichlorophenyl isocyanate, as the hydrolysis will take place fully, well before the regular test medium is exchanged. The short-term toxicity towards aquatic invertebrates and toxicity towards algae was therefore investigated using the hydrolysis product 3,4-dichloronaniline.

Analytical monitoring:

yes

Test organisms (species):

Phaeodactylum tricornutum

Nominal and measured concentrations:

effective concentration (analysed at the end of test, > 10%)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.1 mg/L

Basis for effect:

growth rate

Validity criteria fulfilled:

not specified

Conclusions:

After 72 h exposure, an EC50 of 1.1 mg/l (based on growth rate) was obtained for 3,4-dichloroaniline (the main hydrolysis product of 3,4 -dichlorophenyl isocyanate).

Executive summary:

Kusk, 1992

Concerning the acute toxicity of 3,4-dichloroaniline to aquatic plants (Phaeodactylum tricornutum), a study was performed according to ISO 8692. After 72 h exposure, an EC50 of 1.1 mg/l (based on growth rate) was obtained. For further details please refer to chapter 13.2.

 

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

peer-reviewed in the BUA report

Justification for type of information:

Due to insufficient reporting of the experimental details, this study was rated with a Klimisch score of 4 (‘not assignable’). As none of the available studies can serve as a key study with a sufficiently detailed reporting justifying a Klimisch score of 1 or 2 for the given endpoint, several independent sources were used in a weight of evidence approach. ‘Using weight of evidence implies that no single study of sufficient quality and reliability exists, and that information from several independent sources is required to be able to reach a conclusion on a particular property of the substance.' (guidance document How to prepare registration and PPORD dossiers, p. 87)
For further details on the justification for the use of data on the hydrolysis product 3,4-dichloroaniline please refer to chapter 13.2.

Qualifier:

according to guideline

Guideline:

other: DIN 38 412, part 9, 1988

Deviations:

yes

Remarks:

shorter test duration; use of glass stoppers instead of metal caps

GLP compliance:

not specified

Specific details on test material used for the study:

The hydrolysis of 3,4-dichlorophenyl isocyanate is expected to occur faster than within 12 h (Please refer to the expert statement in section 13.) Thus, it is technically not feasible to conduct toxicity tests towards the aquatic species with the test item 3,4-dichlorophenyl isocyanate, as the hydrolysis will take place fully, well before the regular test medium is exchanged. The short-term toxicity towards aquatic invertebrates and toxicity towards algae was therefore investigated using the hydrolysis product 3,4-dichloronaniline.

Analytical monitoring:

not specified

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

strain number 8681 SAG

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

24 +/- 1 °C

pH:

8.0 +/- 0.3 (initial)

Nominal and measured concentrations:

nominal: 0.06 - 8.0 mg/L

Details on test conditions:

constant light
50% relative humidity

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

1.5 mg/L

Basis for effect:

biomass

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6.8 mg/L

Basis for effect:

biomass

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

2.4 mg/L

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

27 mg/L

Nominal / measured:

estimated

Basis for effect:

growth rate

Validity criteria fulfilled:

not specified

Conclusions:

After 48 h exposure, an EC50 of 27 mg/l (based on growth rate) and 6.8 mg/l (based on biomass) was obtained for 3,4-dichloroaniline (the main hydrolysis product of 3,4-dichlorophenyl isocyanate).

Executive summary:

Kuehn, 1990

Concerning the acute toxicity of 3,4-dichloroaniline to aquatic plants (Desmodesmus subspicatus, previous name: Scenedesmus subspicatus), a study was performed according to DIN 38 412, part 9, 1988 (deviation: shorter exposure time). After 48 h exposure, an EC50 of 27 mg/l (based on growth rate) and 6.8 mg/l (based on biomass) as well as EC10 values of 1.5 mg/l (based on biomass) and 2.4 mg/l (based on growth rate) were obtained. 

 

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance with national standard method with accetable restrictions. Basic data given. Peer-reviewed data from EU-RAR of the hydrolysis product 3,4-dichloroaniline

Justification for type of information:

Due to insufficient reporting of the experimental details, this study was rated with a Klimisch score of 4 (‘not assignable’). As none of the available studies can serve as a key study with a sufficiently detailed reporting justifying a Klimisch score of 1 or 2 for the given endpoint, several independent sources were used in a weight of evidence approach. ‘Using weight of evidence implies that no single study of sufficient quality and reliability exists, and that information from several independent sources is required to be able to reach a conclusion on a particular property of the substance.' (guidance document How to prepare registration and PPORD dossiers, p. 87)
For further details on the justification for the use of data on the hydrolysis product 3,4-dichloroaniline please refer to chapter 13.2.

Principles of method if other than guideline:

national standard method: described in handbook "Degradability, Ecotoxicity and Bioaccumulation; The determination of the possible effects of chemicals and wastes on the aquatic environment (TNO, 1980)"

GLP compliance:

no

Specific details on test material used for the study:

The hydrolysis of 3,4-dichlorophenyl isocyanate is expected to occur faster than within 12 h (Please refer to the expert statement in section 13.) Thus, it is technically not feasible to conduct toxicity tests towards the aquatic species with the test item 3,4-dichlorophenyl isocyanate, as the hydrolysis will take place fully, well before the regular test medium is exchanged. The short-term toxicity towards aquatic invertebrates and toxicity towards algae was therefore investigated using the hydrolysis product 3,4-dichloronaniline.

Analytical monitoring:

yes

Details on sampling:

at test start

Vehicle:

not specified

Test organisms (species):

Scenedesmus pannonicus

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

hard

Test temperature:

about 20°C

pH:

8

Dissolved oxygen:

never less than 70 % of the saturation value

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

4.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Since it is not clear whether the results relate to nominal or measured concentrations, the results are interpreted as nominal values.

Validity criteria fulfilled:

not specified

Conclusions:

After 96 h exposure, a EC50 of 4.8 mg/l and a NOEC of 1.0 mg/l was obtained for 3,4-dichloroaniline (the main hydrolysis product of 3,4 -dichlorophenyl isocyanate).

Executive summary:

Adema, 1982

Concerning the acute toxicity of 3,4-dichloroaniline to aquatic plants (Scenedesmus pannonicus), a study was performed according to a national standard method (TNO, 1980). After 96 h exposure, an EC50 of 4.8 mg/l and a NOEC of 1.0 mg/l (based on growth rate) was obtained. For further details please refer to chapter 13.2.

Description of key information

For 3,4-dichlorophenyl isocyanate no short-term tests on toxicity to aquatic plants are available. Therefore, the short-term toxicity test of the main hydrolysis product 3,4-dichloroaniline with the lowest value is used to draw a conclusion on toxicity to aquatic plants for the parent compound. For further details please refer to chapter 13.2.

In order to fulfill the data requirements a weight of evidence (WoE) approach (REACh Regulation (EC) No. 1907/2006, Annex XI Section 1.2) was chosen. This approach is a possible adaptation to the standard information requirements which ‘should be undertaken to maximise the use of existing data and minimise the commissioning of new in vivo testing’ (ECHA Guidance R.7a, 2017, p. 364). The WoE approach serves to reduce or avoid animal testing, which should only be performed as last resort (REACh, article 25). The individual study reports were conducted in accordance with standardized guidelines. The study reports nevertheless show some deficiencies with respect to the comprehensiveness of the presented experimental details. Therefore, a reliability of 1 or 2 and thus adequacy as key study was not assignable for any of the individual studies. Consequently, the studies were assigned a Klimisch score of 4 (according to guidance document R.4, ‘not assignable: studies or data […] which do not give sufficient experimental details […]). Collectively, these experimental studies can be used to conclude on this endpoint and to satisfy the information requirement.

Adema, 1982

Concerning the acute toxicity of 3,4-dichloroaniline to aquatic plants (Scenedesmus pannonicus), a study was performed according to a national standard method (TNO, 1980). After 96 h exposure, an EC50 of 4.8 mg/l and a NOEC of 1.0 mg/l (based on growth rate) was obtained. 

Kuehn, 1990

Concerning the acute toxicity of 3,4-dichloroaniline to aquatic plants (Desmodesmus subspicatus, previous name: Scenedesmus subspicatus), a study was performed according to DIN 38 412, part 9, 1988 (deviation: shorter exposure time). After 48 h exposure, an EC50 of 27 mg/l (based on growth rate) and 6.8 mg/l (based on biomass) as well as EC10 values of 1.5 mg/l (based on biomass) and 2.4 mg/l (based on growth rate) were obtained. 

Kusk, 1992

Concerning the acute toxicity of 3,4-dichloroaniline to aquatic plants (Phaeodactylum tricornutum), a study was performed according to ISO 8692. After 72 h exposure, an EC50 of 1.1 mg/l (based on growth rate) was obtained. 

Conclusion

The EC50 values obtained from these studies are in the same order of magnitude, but differ in exposure time and species (1.0-27 mg/L).

As key values for chemical saftey assessment the EC50 of 4.8 mg/l and a NOEC of 1.0 mg/l (based on growth rate) obtained by Adema, 1982 were chosen, as these values were obtained for a test species similar to those recommended by OECD TG 201 and with an appropriate exposure time.

Key value for chemical safety assessment

EC50 for freshwater algae:

4.8 mg/L

EC10 or NOEC for freshwater algae:

1 mg/L