N-(2-chloroethyl)-4-[(2,6-dichloro-4-nitrophenyl)azo]-N-ethyl-m-toluidine

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

The batch of Disperse Brown 27 (4852-1501) tested was a brown powder with a purity of 99.7 %

Analytical monitoring:

yes

Details on sampling:

Calibration solutions were injected in duplicate. Test samples and QC samples were analyzed by single injection.

Details on test solutions:

A combined limit/range-finding test was performed. A Saturated Solution (SS) was prepared at a loading rate of 100 mg/L and used as the highest concentration. Lower concentrations were prepared by diluting the highest concentration in test medium.

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
Source: In-house laboratory culture with a known history.
Reason for selection: This system has been selected as an internationally accepted invertebrate species.
Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
Characteristics: For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

Test type:

static

Water media type:

other:

Remarks:

Tap water purified by a Milli-Q water purification system

Limit test:

yes

Total exposure duration:

48 h

Hardness:

180 mg/L expressed as CaCO3

Test temperature:

20 °C (study plan specified temperature of 18-22 °C which was constant within 2 °C).

pH:

7.7 ± 0.3

Dissolved oxygen:

Control( t=0 9.2 mg/L, t=48 h 10.5 mg/L)
100 (t=0 8.5 mg/L, t=48 h 10.3 mg/L)

Nominal and measured concentrations:

Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to the undiluted SS prepared at a loading rate of 100 mg/L. In addition ten daphnids per group (5 per replicate, duplicate) were exposed to solutions containing 1.0% and 10% of the SS. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test. Samples taken from the limit concentration were analysed and showed a measured initial concentrations of 0.282 μg/L. This concentration decreased during the test period to 58% of initial at the end of the test. Based on these results the average exposure concentration was 0.22 μg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.22 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Analyses of the samples taken from the undiluted SS showed a concentration of 0.28 μg/L at the start of the test. This measured concentration decreased to 58% of initial at the end of the test. Based on this results, an average exposure concentration of 0.22 μg/L was used to determine effect parameters.
No immobility was observed in the control and at any of the test concentrations during the test period.

Validity criteria fulfilled:

yes

Conclusions:

In conclusion, the 48h-EC50 for Daphnia magna exposed to Disperse Brown 27 exceeded an average exposure concentration of 0.22 μg/L, which was considered to be the maximum solubility limit of Disperse Brown 27 in medium.

Executive summary:

The objective of the study was to evaluate Disperse Brown 27 for its ability to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours and, if possible, to determine the EC50 at 24 and 48 hours of exposure.

A combined limit/range-finding test was performed. A Saturated Solution (SS) was prepared at a loading rate of 100 mg/L and used as the highest concentration. Lower concentrations were prepared by diluting the highest concentration in test medium. Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to the undiluted SS prepared at a loading rate of 100 mg/L. In addition ten daphnids per group (5 per replicate, duplicate) were exposed to solutions containing 1.0% and 10% of the SS. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test.

Samples taken from the limit concentration were analysed and showed a measured initial concentrations of 0.282 μg/L. This concentration decreased during the test period to 58% of initial at the end of the test. Based on these results the average exposure concentration was 0.22 μg/L

The study met the acceptability criteria prescribed by the study plan and was considered valid.

Description of key information

The objective of the study was to evaluate Disperse Brown 27 for its ability to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours and, if possible, to determine the EC50 at 24 and 48 hours of exposure.

A combined limit/range-finding test was performed. A Saturated Solution (SS) was prepared at a loading rate of 100 mg/L and used as the highest concentration. Lower concentrations were prepared by diluting the highest concentration in test medium. Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to the undiluted SS prepared at a loading rate of 100 mg/L. In addition ten daphnids per group (5 per replicate, duplicate) were exposed to solutions containing 1.0% and 10% of the SS. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test.

Samples taken from the limit concentration were analysed and showed a measured initial concentrations of 0.282 μg/L. This concentration decreased during the test period to 58% of initial at the end of the test. Based on these results the average exposure concentration was 0.22 μg/L

Additional information

In conclusion, the 48h-EC50 for Daphnia magna exposed to Disperse Brown 27 exceeded an average exposure concentration of 0.22 μg/L, which was considered to be the maximum solubility limit of Disperse Brown 27 in medium.