Cyclododecane

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

Study period:

1994-10-25 to 1994-10-28

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions: Test substance not stable under test condition

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

Cited as Directive 92/69/EEC, C.3

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Cyclododecane

EC Number:

206-033-9

EC Name:

Cyclododecane

Cas Number:

294-62-2

Molecular formula:

C12H24

IUPAC Name:

cyclododecane

Details on test material:

Test substance: cyclododecane of Hüls AG, produced 19 May 1993, purity 99.8% (GC-FID area); ID No. 0637/81524, PR No. 1452/931213

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

STOCK AND TEST SOLUTION AND THEIR PREPARATION
- 1 g/l stirred in deionized water for about 18 h and  filtered (Water Accomodated Fraction)

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISMS
- Strain: Scenedesmus subspicatus CHODAT (86.81 SAG)
- Source/supplier: Origin: Institut fuer Wasser-, Boden- und Lufthygiene, Berlin, further bred inhouse
- Laboratory culture: From a stock culture, a preculture is seeded three  days before begin of test. Test cultures are seeded from the latter
- Method of cultivation: Erlenmeyer flasks under light benches
- Controls: yes
- Initial cell concentration: ca. 20 000 cells/ml

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

22.6-23.2 degree C

pH:

8.3-8.9 (begin) 8.3-8.7 (end of study)

Nominal and measured concentrations:

- Concentrations: 0.14; 0.23; 0.39; 0.69; 1.2; 2.1 mg/l (nominal)

Details on test conditions:

GROWTH/TEST MEDIUM CHEMISTRY
- see Test Guideline

TEST SYSTEM
- Renewal of test solution: no
- Exposure vessel type: Erlenmeyer flasks under light benches
- Number of replicates: 5 or 8, probably 8 for control, 5 for each concentration > 0

- Intensity of irradiation: approximately 8,000 lux, white

TEST PARAMETER
- photometric determination of cell numbers at 685 nm, calibration with standard curve

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 2.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 2.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Any other information on results incl. tables

- Cell density data: (x 1.0E+04 cells/ml)
  concentration    0 hours   24 hours   48 hours   72 hours
  control             2          3          18        73
  0.14 mg/l           2          4          17        82
  0.23 mg/l           2          4          16        80
  0.39 mg/l           2          4          20        88
  0.69 mg/l           2          5          19        78
  1.20 mg/l           2          4          18        76
  2.10 mg/l           2          4          17        85

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The EC50 (72 h, based on growth rate) was determined as >2.1 mg/L indicating that no toxic effects were observed on algae up to the highest soluble concentration.

Executive summary:

The growth inhibition of cyclododecane on Scenedesmus subspicatus was studied in a 72 -h growth inhibion test by Hüls AG (1995) according to EU method C.3. Algae cell numbers were determined at six test concentrations ranging from 0.14 mg/L to 2.1 mg/L plus controls at dailiy intervals. No effects were observed at any test concentration within the study period. Thus the EC50 was determined to be >2.1 mg/L. The study was assessed as "reliable with restrictions".