Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
22 - 25 Jul 1999
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restrictions (no purity)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
(1984)
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
yes (incl. certificate)
Remarks:
The Department of Health of the Government of the United Kingdom (date of inspection 23 Mar 1998)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 3,5,5-TRIMETHYLHEXANOIC ACID, MIXED TETRAESTERS WITH PENTAERYTHRITOL AND VALERIC ACID- Substance type: straw coloured liquid- Physical state: liquid- Analytical purity: no data- Storage condition of test material: room temperature in the dark

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: Water samples were taken from the control (replicates R1-R2 pooled) and the 100 mg/L loading rate WSF test group (replicates R1-R3 and R4-R6 pooled) at 0 and 72 h.- Sample storage conditions before analysis: Duplicate samples were taken at 0 h and stored frozen (approx. -20°C) for further analysis if necessary.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION- Method: An amount of test material (2000 mg) was added to the vortex created in 20 L of culture medium to give a 100 mg/L loading rate. The mixture was stirred for 23 h with a vortex depth of approx. 25%. After stirring the mixture was allowed to stand for 1 h prior to the removal of the WSF by filtration through 0.45 µm filters. An aliquot (2000 mL) of the WSF was inoculated with algal suspension (10 mL) to give the final test concentration of 100 mg/L loading rate WSF. - Controls: reverse osmosis purified deionised water (Elga Optima 15+) without test item

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM- Common name: green algae- Strain: CCAP 276/20- Source: Culture Centre for Algae and Protozoa (CCAP), Institute of Freshwater Ecology, Ferry House, Ambleside, Cumbria- Method of cultivation: The culture was maintained in the laboratory at a temperature of 21 ± 1 °C under continuous light (approx. 7000 lux) and constant aeration. The culture medium was prepared according to the OECD guideline (AAP medium).

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h

Test conditions

Test temperature:
24 ± 1 °C
pH:
7.3-7.6 (0 h), 8.0-8.8 (control, 72 h), 8.8 - 9.7 (100 mg/L, 72 h)
Nominal and measured concentrations:
Nominal concentrations: 100 mg/LMeasured concentrations: 100 mg/L (12.6 and 17.9 mg/L, 0 h; 5.89 and 2.07 mg/L, 72 h)
Details on test conditions:
TEST SYSTEM- Test vessel: 250 mL glass conical flasks each containing 100 mL of solution- Type: covered with aluminium foil- Aeration: constantly shaken at 100 rpm- Initial cells density: 1.26 - 1.66x10E+04 cells/mL- Control end cells density: 3.64x10E+05 cells/mL- No. of vessels per concentration: 6- No. of vessels per control: 3GROWTH MEDIUM- Standard medium used: yes, according to OECD guidelineTEST MEDIUM / WATER PARAMETERS- Source/preparation of dilution water: reverse osmosis purified deionised water (Elga Optima 15+)OTHER TEST CONDITIONS- Adjustment of pH: adjusted to 7.5 ± 0.1 with 0.1 N NaOH or HCl- Photoperiod: continuous light- Light intensity and quality: approx. 7000 luxEFFECT PARAMETERS MEASURED: - Determination of cell concentrations: samples were taken at 0, 24, 48 and 72 h and the cell densities were determined by using a Coulter Multisizer II Particle CounterTEST CONCENTRATIONS- Range finding study- Test concentrations: 100 mg/L (WAF)- Results used to determine the conditions for the definitive study: No effect on growth at 100 mg/L loading rate WAF.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EL50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
(WAF)
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOELR
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
(WAF)
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EL50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
(WAF)
Basis for effect:
biomass
Details on results:
- Exponential growth in the control: yes- Any stimulation of growth found in any treatment: an increase of growth was observed in the highest test concentration after 72 h.- Effect concentrations exceeding solubility of substance in test medium: The nominal effect concentration of 100 mg/L exceeded the water solubility of the test substance.
Reported statistics and error estimates:
Statistical analysis of the area under the growth curve data was carried out for the control and 100 mg/L loading rate WSF test group using a Students t-test.

Any other information on results incl. tables

No effects on the growth rate was observed in the range of water solubility of the test substance with an EL50 of > 100 mg/L based on the growth rate. The measured concentrations of the test item in the test vessels were much lower than the nominal loading rate (Table 3).

Table 1: Cell densities in the definitive study

 

Cell densities [cells/mL]

Nominal loading rate [mg/L]

0 h

24 h

48 h

72 h

Control R1

1.34x104

2.29 x104

7.69 x104

3.79 x105

R2

1.34 x104

2.16 x104

8.80 x104

3.53 x105

R3

1.10 x104

2.22 x104

9.83 x104

3.60 x105

Mean

1.26 x104

2.22 x104

8.78 x104

3.64 x105

100 R1

1.67 x104

2.38 x104

6.14 x104

5.19 x105

R2

1.80 x104

2.42 x104

8.11 x104

5.23 x105

R3

1.37 x104

2.44 x104

6.29 x104

3.50 x105

R4

1.54 x104

2.49 x104

7.26 x104

4.01 x105

R5

1.93 x104

2.41 x104

7.64 x104

6.62 x105

R6

1.61 x104

2.41 x104

6.60 x104

6.65 x105

Mean

1.66 x104

2.42 x104

7.01 x104

5.20 x105

Table 2: Inhibition of growth rate and biomass

Nominal loading rate [mg/L]

Area under curve at 72 h

% inhibition

Growth rate (0-72 h)

% inhibition

control

6.25 x106

-

0.047

 

100

7.51 x106

[20]

0.048

[2]

[increase in growth as compared to the controls]

Table 3: Chemical analysis of test loading rates

Samples

Nominal loading rate [mg/L]

Concentration found [mg/L]

Expressed as a % of the nominal loading rate

0 h

control

< LOQ

-

100 R1-R3

12.6

13

100 R4-R6

17.9

18

72 h

control

< LOQ

-

100 R1-R3

5.89

6

100 R4-R6

2.07

2

Applicant's summary and conclusion