Methylurea

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline Study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Methylurea

EC Number:

209-935-0

EC Name:

Methylurea

Cas Number:

598-50-5

Molecular formula:

C2H6N2O

IUPAC Name:

methylurea

Details on test material:

- Name of test material (as cited in study report): Methylharnstoff
- Lot/batch No.: 001V36AX10
- Analytical purity: 98 %

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution(125.5 mg/l) was prepared by stirring the test substance in demineralized water for about 10 min at approximately 20 ± 2°C .

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: CHODAT SAG 86 .81
- Source (laboratory, culture collection):

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

23 ± 2 °C

pH:

7.9 - 8.5

Nominal and measured concentrations:

Nominal test substance concentrations:
12.5, 25, 50, 100 mg/l

Analytical test substance concentrations:
12.0 (12.5 nominal), 96.1 (100 nominal) mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks (250 ml)
- Fill volume: 100 ml
- Initial cells density: 10000
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Test medium according to The test substance was stirred in demineralized water for about 10 min at approximately 20 t 2°C .
The stock solution appears clear and colourless .
The nominal concentration of the stock solution was 125,5 mg/I .EEC Directive 92/69/EEC, Annex V, Part C.3 .

OTHER TEST CONDITIONS
- Photoperiod: permanent illumination
- Light intensity and quality: artificial light, type universal white (OSRAM L 25), about 60 - 120 µE/(m²s) at a wave length of 400 - 700 nm


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber (Neubauer improved)
- Chlorophyll measurement: vivo chlorophyll-a-fluorescence (pulsed excitation with light flashes having a wavelength of 435 nm

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate