1-ethyl-1,2-dihydro-6-hydroxy-4-methyl-5-[(2-nitrophenyl)azo]-2-oxonicotinonitrile

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:

20 - 22 Mar 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no information on positive control given

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

425-310-7

EC Name:

-

Cas Number:

77889-90-8

Molecular formula:

C14H10ClN5O4

IUPAC Name:

5-[2-(4-chloro-2-nitrophenyl)diazen-1-yl]-6-hydroxy-1,4-dimethyl-2-oxo-1,2-dihydropyridine-3-carbonitrile

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, 100 mg/L
- Sampling method: 20 mL of test solution taken from test vessel, evaporated and resolved in methanol : DMF 50:50 (v/v)

Test solutions

Vehicle:

no

Details on test solutions:

The test substance was weighed directly into the test chambers, mixed with water for dilution and homogenized with Ultra-Turrax and ultrasonic bath. After 48 h of settlement, the supertanant was used for test media preparation.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Clone 5
- Source: IRChA, France
- Age of parental stock: max. 42 d
- Feeding during test: no
- Food type: freshwater green algae
- Frequency: thrice a week

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

20.1 - 20.4°C

pH:

8.1 - 8.3

Dissolved oxygen:

8.3 - 9.2 mg/L

Nominal and measured concentrations:

0 (control), 100 mg/L nominal

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL nominal volume glass beaker, 70 mL fill volume
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: no, both time Elendt M4 medium

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 12/12 h

EFFECT PARAMETERS MEASURED: mobility at 0, 24, 48 h

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 19.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

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:

Due to the low water solubility and the 48 h settlement period in the test solution before the started, a low recovery of 19.8% (mean) was noticed.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test item does not have any toxicity effect to freshwater invertebrates up to the limit of water solubility. Due to the low recovery rate in the test solutions, the key value is related to mean measured concentrations (19.8 mg/L) which is still far above the water solubility limit.