potassium (oxido-NNO-azoxy)cyclohexane; cyclohexylhydroxydiazene 1-oxide, potassium salt; [K-HDO]

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:

Begin of the study: 27 Feb 2002; experimental phase: 05 Mar 2002 - 07 Mar 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

4 April 1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Cyclohexylhydroxydiazene 1-oxide, potassium salt

EC Number:

613-953-8

Cas Number:

66603-10-9

Molecular formula:

C6H11KN2O2

IUPAC Name:

Cyclohexylhydroxydiazene 1-oxide, potassium salt

Test material form:

liquid

Details on test material:

Xyligen 30F is a 30% aqueous solution of K-HDO.

Specific details on test material used for the study:

see table below

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The analyses were carried out as a separate study at the test facility Analytical Department of BASF Aktiengesellschaft under the responsibility of the Study Director of this test facility. The study was carried out in compliance with the Principles of Good Laboratory Practice. The concentration control analyses were performed with test solutions of the following nominal concentrations (mg/L) of the test substance: 0 – 100 – 6.25

Test solutions

Vehicle:

yes

Remarks:

"M4 water"

Details on test solutions:

PREPARATION OF THE STOCK SOLUTION AND DILUTION:
The test substance (Xyligen 30 F) was stirred in M4 medium for about 10 minutes at 20 ± 2°C. The nominal concentration of the stock solution was 100 mg/L.
By diluting this stock solution with M4 medium the following nominal concentrations (mg/L) were prepared: 0 (control) - 100 – 50 – 25 – 12.5 – 6.25

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM:
- Common name: Daphnia magna Strauss
- Strain/clone: The clone of Daphnia magna STRAUS 1820 used was supplied by the Institut National de Recherche Chimique Appliquée, France, in 1978. From this date on this clone was cultured and bred continuously in the Laboratory Experimental Toxicology and Ecology of BASF AG in Ludwigshafen.
- Source: Institut National de Recherche Chimique Appliquée
- Age of parental stock (mean and range, SD): 2-4 weeks
- Age of the animals at the begin of exposition: 2 - 24 h (starting with the 3rd breed of parent animals)
- Feeding during test: no

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Not required for this kind of test.

Test conditions

Hardness:

Total hardness: 2.20 – 3.20 mmol/L

Test temperature:

18 - 22 °C (max. temperature difference 2 °C)

pH:

pH value: 7.5 -8.5

Dissolved oxygen:

Test medium was saturated with oxygen

Salinity:

Molar ratio Ca : Mg: about 4 : 1

Conductivity:

Conductivity: 550 - 650 µS/cm

Nominal and measured concentrations:

Measured concentrations correspond to the nominal concentrations (recovery rate ≥ 98 %). Details are presented in the table below.

Details on test conditions:

TEST SYSTEM
see table below

RANGE-FINDING STUDY
- Test concentrations: The test concentrations were determined in a range finding test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

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

Effect concentrations 3

Key result

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

See table below

Results with reference substance (positive control):

The EC50(24h) of the control substance potassium dichromate (non-GLP) was 1.07 mg/L (Date of the last control experiment : 18 Feb 2002, project number: 97/0242/50/72).

Reported statistics and error estimates:

Due to the results of the test no statistical evaluation of the data was performed.

Any other information on results incl. tables

Number of mobile Daphnids in the different test concentrations:

Conc.	Parallel 1			Parallel 2			Parallel 3			Parallel 4			∑	∑
[mg/L]	[mg/L]			[mg/L]			[mg/L]			[mg/L]			h
	0	24	48	0	24	48	0	24	48	0	24	48	24	48
Control	5	5	5	5	5	5	5	5	5	5	5	5	20	20
100	5	5	5	5	5	5	5	5	4	5	4	4	19	18
50	5	5	5	5	4	4	5	5	5	5	5	5	19	19
25	5	5	5	5	5	5	5	5	5	5	5	5	20	20
12.5	5	5	5	5	5	5	5	5	5	5	5	5	20	20
6.25	5	5	5	5	5	5	5	5	5	5	5	5	20	20

Number of test animals per replicate: 5

Number of test animals per concentration: 20

Concentration control analysis:

Analytically measured relative minimum and maximum concentrations of the test substance in the test solutions.

Time [h]	Stocked with daphnids	Minimum [%]	Maximum [%]
0	No	100.5	102.0
48	No	98.0	100.0

The values are given in percent of the nominal concentrations:

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

EC50 (48 h) and EC100 (48 h) > 100 mg/L Xyligen 30 F (K-HDO 30 % in water) .

VALIDITY CRITERIA:
• In the control the immobilization was ≤ 10%.
• In the control no daphnids were captured in a surface film.
• The O2-concentration was > 3 mg/L in all tested replicates.
• The EC50(24h) of the control substance potassium dichromate (non-GLP) was 1.07 mg/L
(Date of the last control experiment: 18 Feb 2002, project number: 97/0242/50/72).
The test is valid.

Executive summary:

The test substance was tested in the range of concentrations between 100 mg/L and 6.25 mg/L. The dilution factor was 2. Instead of mortality the test criterion of acute toxicity is immobilization of the daphnids after 48 hours of exposure which is expressed as EC (effect concentration). Those animals were considered to be immobile which were unable to swim within 15 seconds even after gentle agitation of the test vessel.

According to the results of the test the EC₅₀ and EC₁₀₀ value is greater than 100 mg/L.