2-nitrotoluene

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

Version: 1984

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (as cited in study report): 2-Nitrotoluene
- Analytical purity: >99%
- Supplier: Fluka, Buchs, Switzerland

Analytical monitoring:

yes

Details on sampling:

- test substance concentration was measured in each flask at the beginning and the end of the test

Details on test solutions:

- Stock solutions were prepared directly in the culture medium and stirred for at least 24 h.
- Stock solutions were used to prepare fresh test solutions by dilution with medium.
- Algae were exposed in triplicate to 5 concentration levels and one control.
- Concentration levels were prepared with a dilution factor of 2.

Test organisms (species):

Chlorella pyrenoidosa

Details on test organisms:

culture of Chlorella pyrenoidosa:
- original culture was provided by H. Oldersman from TNO (Delft, The Netherlands)
- alga were cultured in Miller's solution using a 100 ml bottle, which was renewed (1:5) at least once a week
- algal cultures were incubated on top of a series of TL tubes and shaken by a microplate shaker at 300 rpm

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

approximately 22°C
=> measured in each flask at the beginning and the end of the test

pH:

approximately 7.4
=> measured in each flask at the beginning and the end of the test

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

8.7 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4.4 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

other: NEC

Effect conc.:

19.7 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth rate

Remarks on result:

other: S.E. ± 1.9

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

8.3 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

22 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 16-30

Fulfilling one of the OECD's validity criteria the average population growth rate of the controls was 1.0 per day.

Validity criteria fulfilled:

yes

Remarks:

The average population growth rate of the controls was 1.0 per day. (The cell concentration in the control cultures should have increased by a factor of at least 16 within three days.This corresponds to a specific growth rate of 0.92 per day)

Conclusions:

Ramos et al. (1999) tested the effects on the population growth of the algae Chlorella pyrenoidosa according to the OECD 201 guideline (1984). The NOEC was 4.4 mg/L. Tests were carried out for 72h. Algae were exposed, in triplicate, to five concentration levels and one control. The pH and temperature values in the tests were approximately 7.4 and 22 ºC, respectively, and the average growth rate of the controls was 1.0 day-1. The study, considered valid for the assessment, provided an EC50 of 22 mg/l (ranging between 16 and 30 mg/l).

Executive summary:

Ramos et al. (1999) tested the effects on the population growth of the algae Chlorella pyrenoidosa according to the OECD 201 guideline (1984). The NOEC was 4.4 mg/L. Tests were carried out for 72h. Algae were exposed, in triplicate, to five concentration levels and one control. The pH and temperature values in the tests were approximately 7.4 and 22 ºC, respectively, and the average growth rate of the controls was 1.0 day-1. The study, considered valid for the assessment, provided an EC50 of 22 mg/l (ranging between 16 and 30 mg/l).

Description of key information

Ramos et al. (1999) tested the effects on the population growth of the algae Chlorella pyrenoidosa according to the OECD 201 guideline (1984). The NOEC was 4.4 mg/L. Tests were carried out for 72h. Algae were exposed, in triplicate, to five concentration levels and one control. The pH and temperature values in the tests were approximately 7.4 and 22 ºC, respectively, and the average growth rate of the controls was 1.0 day-1. The study, considered valid for the assessment, provided an EC50 of 22 mg/l (ranging between 16 and 30 mg/l).

Key value for chemical safety assessment

EC50 for freshwater algae:

22 mg/L

EC10 or NOEC for freshwater algae:

4.4 mg/L