2,4-dihydro-5-methyl-2-phenyl-4-(phenylazo)-3H-pyrazol-3-one

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: well performed OECD study with GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,4-dihydro-5-methyl-2-phenyl-4-(phenylazo)-3H-pyrazol-3-one

EC Number:

224-330-1

Cas Number:

4314-14-1

Molecular formula:

C16H14N4O

IUPAC Name:

2,4-dihydro-5-methyl-2-phenyl-4-(phenylazo)-3H-pyrazol-3-one

Details on test material:

purity: 98.9 %

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Stock solution: The solution (100 mg/L test item was weighed out) was prepared with dilution water in brown glass flask one day day prior to
application.
Dispersion treatment: The stock solution was shaken with 20 rpm for 24 h (rotating shaker 3040, GFL). Undissolved particles were removed by
membrane filtration (0.45 μm, RC, SCHLEICHER & SCHUELL).
Limit concentration: Saturated solution

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna STRAUS (Clone 5)
- Source: Institut für Wasser-, Boden- und Lufthygiene
- Breeder: DR.U.NOACK-LABORATORIEN, 31157 Sarstedt, Germany
- Culture: In 2-3 L glass vessels with approximately 1.8 L culture medium, at 20 ± 2 °C, in an incubator, 16 h illumination, illumination
strength max. 20 μE⋅m-2 ⋅s-1
- Culture medium: Elendt M4, according to Elendt (1990), modified to a total hardness of 160 to 180 mg CaCO3/L.
- Feeding during test: no
- Age of the test organism: 2 - 24 h


ACCLIMATION
- Acclimatisation: at least 2h in dilution water
- Feeding: At least 5 per week ad libitum with a mix of Desmodesmus subspicatus and Chlorella vulgaris, with an algae cell density
of > 106 cells/mL.

Number of test organisms per concentration and control:
20 animals, divided into 4 parallel samples, each with 5 animals

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

no

Test conditions

Hardness:

263 mg CaCO3/L

Test temperature:

18 - 22 °C

Dissolved oxygen:

8.42 mg/L

Nominal and measured concentrations:

nominal 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (5 cm ID x 8 cm H), 50 mL volume
- Type (delete if not applicable): open
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Preparation of dilution water: According to Directive 92/69/EC L383A C.2. Annex

OTHER TEST CONDITIONS
- Photoperiod: 16/8 h light/dark cycle
- Light intensity: Diffuse light, illumination range max. 20 μE⋅m-2 ⋅ s-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

Preliminary study:
with 1:1, 1:10. 1.100 dilutions with 10 daphnids:
no immobilisation after 24 h and 48 h

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: immoblisation

Remarks on result:

other: saturated solution

Results with reference substance (positive control):

The percentage immobility for the reference item was determined after 24 h. The EC50- with
95 % confidence interval (CI) was determined by sigmoidal dose-response regression. ECvalues
after 24 h of the reference item in mg/L:
EC50 : 1.95 (CI 1.71 - 2.16)
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 P 9/2 (05/1996) for
daphnids clone 5 cultured in Elendt M4 medium.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

At the saturated solution of the test item no biologically significant effect to Daphnia Magna effect was determined

Executive summary:

In the acute immobilisation test with Daphnia magna (STRAUS) the effect of the saturated solution# (DOC 3.4 mg/L) of the test item was determined according to OECD 202 (2004) . The limit test was conducted under static conditions over 48 h . 20 test organisms were exposed to the saturated solution and the control.

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 1.95 mg/L after 24 h was within the prescribed concentration range of 1.0 to 2.5 mg/L according to AQS. 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.

The test item was visually clear dissolved at the tested saturated solution throughout the exposure period. No immobility was determined in the tested saturated solution after 24 h and 48 h. There is no biologically significant effect neither in the tested saturated solution nor in the control group.