2-[(4-methyl-2-nitrophenyl)azo]-3-oxo-N-phenylbutyramide

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

Study period:

From 09 NOV 2004 to 11 NOV 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented guideline study performed compliant to GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

1999, Draft

Deviations:

yes

Remarks:

No test item analysis

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

No test item analysis

GLP compliance:

yes (incl. QA statement)

Remarks:

according to § 19b Clause. 1 German Chemikaliengesetz and Directive 88/320/EEC

Analytical monitoring:

no

Details on sampling:

As the test item is of very poor solubility (far below 1 mg/L), test item analysis was not possible.

Vehicle:

no

Details on test solutions:

Due to the very poor water solubility, the saturated solution was tested. The saturated solution is definded as the maximum dissolved concentration of the test item that can be achieved under the test conditions in the test medium, acc. to OECD Series, No. 23 (2000)6.
Saturated solutions with a nominal loading of 100 mg test item/L were prepared with dilution water one day prior to application. The stock solution was shaken at room temperature with 20 rpm for 24 h (rotating shaker 3040, GFL) and membrane filtrated with 0.45 µm (RC, SCHLEICHER & SCHUELL).
Limit concentration Saturated solution: 100 mg/L

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna STRAUS (Clone 5)
Origin: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu)
Breeder: DR.U.NOACK-LABORATORIEN, Kathe-Paulus-Str. 1, 31157 Sarstedt, Germany
Culture: In glass vessels (2 - 3 L capacity) with approximately 1.8 L culture medium, at 21 deg C (20-25 deg C tolerated), in an incubator, 16 h illumination, illumination strength max. 20 µM photons x mE(-2) x sE(-1)
Culture medium: Elendt M4, according to ELENDT (1990), modified to a total hardness of 160 to 180 mg CaCO3/L.
Culture feeding: At least 5 times per week ad libitum with a mix of unicellular green algae (Desmodesmus subspicatus and Chlorella vulgaris, with an algae cell density of > 10E(6) cells/mL

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Total hardness of 160 to 180 mg CaCO3/L

Test temperature:

20 +/- 1 deg C

pH:

Control:
7.60 - 7.85
Treatment:
7.54 - 7.69

Dissolved oxygen:

[mg/L]
Control: 7.87 - 8.66
Treatament: 8.02 - 8.39

Nominal and measured concentrations:

As the test item is of very poor solubility in water (far below 1 mg/L), test item analysis was not possible. Therefore, all concentrations refer to the nominal concentration of the saturated solution tested in a limit test (100 mg/L, membrane filtrated before use in the test).

Details on test conditions:

TEST METHOD: Static
Test duration: 48 h. In the definitive study the immobilisation of the daphnids was observed after 24 and 48 hours of exposure. Water parameters
were measured at begin and end of the study (dissolved oxygen concentration, pH value).
Prior to test start pH value, dissolved oxygen concentration, conductivity, total hardness and temperature of the dilution water were measured. The room temperature was recorded throughout the test with a thermohygrograph.
Test vessels: Glass beakers (4 cm ID x 7 cm H), 50 mL capacity
Test volume: 20 mL
Dilution water: ISO Test water, according to OECD 202, Annex 3; pH-value: 7.8 +/- 0.2
Number of daphnids and replicates: 20 daphnids, divided into 4 replicates, each with 5 daphnids per limit loading and control. For the reference substance, two groups with 10 animals, each were tested.
Age of daphnids at the beginning of the test (0 h): 2 to 24 h old daphnids were used for the study. They were obtained by removing the mother animals twice within 22 h.
Acclimiation: approximately 2 hours.
Test temperature: 18 - 22 deg C, +/- 1 deg C constant
Illumination / Photoperiod: Diffuse light, illumination strength max. 20 µmol photons x mE(-2) x sE(-1) / 16/8 h light/dark cycle
Feeding: The daphnids were not fed during the study.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate p.a. (Merck), Batch No. K 28974764, 100% purity

Key result

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Solubility of the Test Item: The test media (saturated solution of the test item) was a clear solution throughout the whole exposure period.
There was no effect on Daphnia magna observed in the saturated solution with a nominal loading of 100 mg/L. Neither in the treatment nor in the control were any immobilized daphnids observed.

Results with reference substance (positive control):

The reference item was tested in five concentrations within the concentration range 0.58 to 5.8 mg/L.
The percentage immobility for the reference item was determined after 24 h. The EC100-value was determined directly from the test results. The EC10- and EC50- with 95 % confidence interval (CI) was determined in a probability network by interpolation according to standard procedures.
EC-values after 24 h of the reference item in mg/L:
EC10 : 0.97
EC50 : 2.07 (CI 1.68 - 2.56)
EC100 : 5.80
The EC50-value of the reference item potassium dichromate after 24 h is within the prescribed concentration range of 1.0 - 2.5 mg/L of quality criteria according to AQS: DIN Guideline 38412 L 30.

Reported statistics and error estimates:

The effects of the limit concentration were determined directly from the observation data without calculations.
EC50- and EC10-values were only calculated for the reference item via probit analysis according to WEBER (1986).
Calculation of the confidence intervals was carried out using standard procedures according to BREITIG G. & TÜMPLING W. (1982).
Software:
All data were computer generated and rounded for presentation from the full derived data. Consequently, if calculated manually based on the given data minor variations may occur from these figures. Calculations were carried out using software:
SigmaPlot rel. 2000 (2000), SPSS CORPORATION

Validity criteria fulfilled:

yes

Conclusions:

With the saturated solution of the submission substance prepared with a nominal loading of 100 mg/L, no effects were observed in an acute immobilization test on Daphnia magna according to OECD 202.

Executive summary:

In the acute immobilisation test with Daphnia magna (STRAUS) the effect of the saturated solution of the submission substance

with a nominal loading of 100 mg/L as limit concentration was determined according to OECD 202 (1999, Draft) and EC Directive

92/69/EC Method C.2 (1992) compliant to GLP (reliability category 1). The limit test was conducted under static conditions over 48 h. 20 test organisms were exposed to the limit concentration and control. Due to the very poor solubility of the test item (far below 1 mg/L) no test item analysis was carried out. After 24 and 48 hours of exposure neither for the treatment (100 mg/L nominal concentration) nor for the control groups any immobilized daphnids could be observed.

A reference test was carried out with potassium dichromate to determine the toxicity of the reference item. The EC50-value of the reference item of 2.07 mg/L after 24 h was within the prescribed concentration range of 1.0 to

2.5 mg/L according to AQS, DIN Guideline 38412 L 30.

Water quality parameters pH-value and dissolved oxygen concentration, measured at 0 and 48 h, were determined to be within the acceptable limits. The validity criteria of the test guideline were fulfilled.

Description of key information

With the saturated solution of the submission substance prepared with a nominal loading of 100 mg/L, no effects were observed in an acute immobilization test on Daphnia magna according to OECD 202.