Registration Dossier

Ecotoxicological information

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:
1997-12-09 to 1997-12-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1997

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Version / remarks:
Cited as Directive 92/69/EEC, C.3
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test substance: cis,cis-1,5-cyclooctadiene (Hüls AG)
Batch B803, produced 10 October 1997
Purity 99.6 % (GC-FID area)
Sample No. 1672/971103
Sample ID 0637/81865

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
STABILITY OF THE TEST CHEMICAL SOLUTIONS
- Parallel samples without algae and without NaHCO3 were analyzed after 0 and 72 hours

Test solutions

Vehicle:
no
Details on test solutions:
STOCK AND TEST SOLUTION AND THEIR PREPARATION
- Concentration of vehicle/solvent: 1 g test substance/l was stirred in deionized water for 18 hours and filtered. 
The resulting concentration  was 57 mg/l. The maximum concentration tested  was 12.5 mg/l. No vehicle  or solvent was used.

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: Institute "Wasser-, Boden- und Lufthygiene",  Berlin; further bred inhouse
- Laboratory culture: A preculture is seeded from a stock culture by transfer 3 days prior to begin of test. Test cultures are seeded from the  latter.
- Controls: yes (0 mg test substance/l)
- Initial cell concentration: approximately 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:
24.1 - 24.4 degree C
pH:
pH: 8.3-8.4 (beginning); 8.9-10.6 (end of test)
Nominal and measured concentrations:
0.13; 0.27; 0.57; 1.25; 2.74; 5.70; 12.5 mg/l (nominal)   
n.d.; n.d.; 0.60; 1.32; 3.14; 6.63; 12.3 mg/l ( 0 hours)   
n.d.; n.d.; 0.23; 0.30; 1.02; 0.84;  3.5 mg/l (72 hours)
"nominal" = calculated from measured concn. of stock sol.; n.d. = not detectable
Details on test conditions:
GROWTH/TEST MEDIUM CHEMISTRY: As described in 92/69/EEC

TEST SYSTEM
- Exposure vessel type: Sterile-aerated Erlenmeyer flasks on light benches, capped with parafilm to avoid volatilization of test substance
- Number of replicates: 5 (test substance) or 8 (control)
- Intensity of irradiation: approx. 8000 lux, white

TEST PARAMETER: Light absorption at 685 nm, related to cell density via  calibration curve

STATISTICAL METHODS
- Probit analysis (Cavalli-Sforza, 1972)
- As the deviation from the initial concentration was not within a range of ± 20 %, analysis of the results was based on geometric mean concentrations
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
2.36 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
2.71 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
4.61 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
> 6.56 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
3.38 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 6.56 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
> 6.56 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
- concentrations up to 0.57 mg/L nominal were "not detectable" and were not considered for the evaluation (no effects up to this level)

Any other information on results incl. tables

RESULTS: EXPOSED AND CONTROL
- Cell density data: 
  Cells/ml after 0; 24; 48; 72 hours (mean)
  -----------------------------------------
  Control:       2;  1; 18; 50 (x 10,000)
  0.63 mg/l:     2;  2; 19; 54 (x 10,000)
  1.79 mg/l:     2;  3; 21; 47 (x 10,000)
  2.36 mg/l:     2;  3; 21; 56 (x 10,000)
  6.56 mg/l:     2;  0;  4; 19 (x 10,000)

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
The EbC50 was determined as 4.61 mg/L and the ErC50 as >6.56 mg/L (highest concentration testes) indicating that the test substance may be toxic to algae.
Executive summary:

The growth inhibition of 1,5 -cyclooctadiene on the alga Scenedesmus subspicatus was evaluated in a 72 -h growth inhibition test by Hüls AG (1998) according to EU Method C.3. Seven concentrations ranging from 0.13 mg/L to 12.5 mg/L (nominal) were tested. The following endpoints were derived:

EbC50 (72 hours): 4.61 mg/L

ErC50 (72 hours): >6.56 mg/L

NOEC (72 hours, based on cell numbers): 2.36 mg/L

The toxicity endpoints were caclulated on the basis of geometrical mean concentrations of the measured test substance concentrations at 0 and 72 hours. The study was assessed as "reliable without restrictions".