1,2-dichloro-3-nitrobenzene

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

effects on growth of green algae

Type of information:

other: peer-reviewed data from OECD SIDS 2004

Adequacy of study:

weight of evidence

Study period:

n/a

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

OECD SIDS 2002

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)

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

no

Test organisms (species):

Selenastrum sp.

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

15 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: Reported as EbC = 15 ppm (w/v))

Validity criteria fulfilled:

not specified

Executive summary:

SIDS final assesment report, 2002 

A 72-h growth inhibition test with Selenastrum capricormutum was performed according to OECD guideline. Tested 1,2-dichloro-3-nitrobenzene had a purity of <99%. The reported EC50 (72h) value is 15 mg/L (w/v), reported as EbC=15 ppm (w/v). Data was obtained from an unpublished report (Report on Toxicity to Fish-HPV/SIDS test conducted by the EA).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

The reported study used insufficiently low test item concentrations (0.1 mg/L was the highest tested concentration limited by the dissolving process) and could therefore only demonstrate that the EC50 value lies somewhere above 0.1 mg/L based on biomass and growth respectively. The report does not specify whether a vehicle has been used for the solubilization of 1,2-dichloro-3-nitrobenzene.

Justification for type of information:

Due to methodological deficiencies, this study was rated with a Klimisch score of 3 (‘not reliable’). 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). Even if rated 'not reliable', the experimental value obtained in this study still supports the WoE conclusion confirming that the EC50 is higher than 0.1 mg/mL.

Principles of method if other than guideline:

Method: other: DIN 38412 Part 9 (1989) modified

GLP compliance:

not specified

Vehicle:

not specified

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.1 mg/L

Basis for effect:

biomass

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.1 mg/L

Basis for effect:

growth rate

Validity criteria fulfilled:

not specified

Executive summary:

Kühn, 1989

In a 48 h toxicity test, an EC50 of >0.1 mg/L based on growth rate and >0.1 mg/L based on biomass was determined for Desmodesmus subspicatus. The results are considered not to be reliable. The reported EC50 values of >0.1 mg/L based on biomass and growth are limited by the solubility of the substance (0.1 mg/L was the highest tested concentration limited by the dissolving process) and thus do not provide a realistic and reliable estimate of the toxicity towards algae. The EC50 value of >0.1 mg/mL overestimates the actual toxicity.

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:

guideline study with acceptable restrictions

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)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

Adopted: 7 June 1984

Deviations:

yes

Remarks:

: slight modifications according to Van Leeuwen et al., 1985

GLP compliance:

not specified

Analytical monitoring:

not specified

Test organisms (species):

Chlorella pyrenoidosa

Water media type:

freshwater

Total exposure duration:

96 h

Nominal and measured concentrations:

Test concentrations increased geometrically with a factor of 3.2.

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

2.9 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

biomass

- the result published in the paper is log EC50 = 1.18 µmol/l

- the result mentioned above was calculated by the applicant based on the reported log IC50

Validity criteria fulfilled:

not specified

Conclusions:

Deneer et al.(1989) determined the effect of 2,3-dichloronitrobenzene on the population growth of Chlorella pyrenoidosa, as described in the OECD guideline 201 (1984), including some slight modifications indicated elsewhere (van Leeuwenet al., 1985). The 96h-log EC50 was 1.18 µmol/l corresponding to an EC50 of 2.9 mg/l.

Executive summary:

Deneer et al.(1989) determined the effect of 2,3-dichloronitrobenzene on the population growth of Chlorella pyrenoidosa, as described in the OECD guideline 201 (1984), including some slight modifications indicated elsewhere (van Leeuwenet al., 1985). The 96h-log EC50 was 1.18 µmol/l corresponding to an EC50 of 2.9 mg/l.

Reference 4

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: Guideline study. Basic data given.

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)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

Adopted: 7 June 1984

Deviations:

yes

Remarks:

: slight modifications according to Van Leeuwen et al., 1985

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

yes

Details on test solutions:

- stock solution was prepared in dimethylsulfoxide (DMSO; merck, purity 99%)

Test organisms (species):

Chlorella pyrenoidosa

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

2.9 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95%C.L. 2.1-4.1

Validity criteria fulfilled:

not specified

Executive summary:

Maas-Diepeveen et al. (1986) determined the effect of 2,3-dichloronitrobenzene on the population growth of Chlorella pyrenoidosa, as described in the OECD guideline 201 (1984). The 96h-EC50 was determined as 2.9 mg/l.

Reference 5

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:

comparable to guideline study with acceptable restrictions

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)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

=> proposal to short-term toxicity test performed on algae (Scenedesmus pannonicus) (1979)

GLP compliance:

not specified

Analytical monitoring:

yes

Test organisms (species):

Scenedesmus pannonicus

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Details on test conditions:

- due to the volatile character of 2,3-Dichloronitrobenzene (see "details in analytical methods") the substance was tested in closed system

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

10 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: growth

All test results were corrected for the actual concentration during the test.

Validity criteria fulfilled:

not specified

Conclusions:

In a 96 h toxicity test, an EC50 of 10 mg/L based on growth was determined for scenedesmus pannonicus.

Executive summary:

In a 96 h toxicity test, an EC50 of 10 mg/L based on growth was determined for scenedesmus pannonicus.

Description of key information

In order to fulfill the data requirements, a weight of evidence (WoE) approach, mentioned in 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 individual study reports show some deficiencies with respect to the comprehensiveness of the experimental details. Therefore, a reliability of 1 or 2 and thus adequacy as key study was not assignable for any of the individual studies. The studies were, however, conducted according to standardized guidelines. 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 and a supporting study on the structural analogue 1,3-dichloro-4-nitrobenzene can be used to conclude on this endpoint and to satisfy the information requirement.

The following studies were chosen for WoE:
Deneer et al. (1989) determined the effect of 2,3-dichloronitrobenzene on the population growth of Chlorella pyrenoidosa, as described in the OECD guideline 201 (1984), including some slight modifications indicated elsewhere (van Leeuwenet al., 1985). The 96h-log EC50 was 1.18 µmol/l corresponding to an EC50 of 2.9 mg/l.

Canton et al. (1985) carried out 96 h toxicity test on algae (Scenedesmus pannonicus) in analogy with the OECD 201 guideline (1979). The authors determined an EC 50 10 mg/L based on growth.

Maas-Diepeveen et al. (1986) determined the effect of 2,3-dichloronitrobenzene on the population growth of Chlorella pyrenoidosa, as described in the OECD guideline 201 (1984). The 96h-EC50 was determined as 2.9 mg/l.

The results obtained in the experimental study by Kühn et al. (1989) were  included in the WoE approach despite being considered not reliable (Klimisch 3). The reported study used insufficiently low test item concentrations (0.1 mg/L was the highest tested concentration limited by the dissolving process) and could therefore only demonstrate that the EC50 value lies somewhere above 0.1 mg/L based on biomass and growth respectively. The above-mentioned studies (Deneer et al. (1989) and Maas-Diepeveen et al. (1986)) made use of DMSO as carrier to enhance the solubility of the substance and are therefore considered reliable. The EC50 value of >0.1 mg/mL overestimates the actual toxicity. This experimental value still supports the WoE conclusion confirming that the EC50 is higher than 0.1 mg/mL.

SIDS final assesment report, 2002: A 72-h growth inhibition test with Selenastrum capricormutum was performed according to OECD guideline. Tested 1,2-dichloro-3-nitrobenzene had a purity of <99%. The reported EC50 (72h) value is 15 mg/L (w/v), reported as EbC=15 ppm (w/v). Data was obtained from an unpublished report (Report on Toxicity to Fish-HPV/SIDS test conducted by the EA).

Supporting study:
In an experimental study on the structural analogue 1,3-dichloro-4-nitrobenzene (Currenta, 2009) the adverse effects of the substance towards the growth of aquatic algae were characterized by an EC50 (48 h) of 5.3 mg/L as well as a NOEC of 2.03 mg/L referring to the reduction of the growth rate. Effective concentrations are based on the geometric mean of measured concentrations. This study is only reported as a supporting study for the existing WoE, as a shorter period of time (48 h versus 96 h) and only a structurally related substance was applied. Nevertheless, the toxic effects are comparable, thus adding additional credibility to the results. This study is therefore supporting the WoE conclusion.

Conclusion
The reported 96h-EC50 values are in the range of 2.9 mg/l to 15 mg/l. Based on the availability and reliability of data and following the most conservative approach the EC50 value of 2.9 mg/L was chosen for assessment.

Key value for chemical safety assessment

EC50 for freshwater algae:

2.9 mg/L