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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:
17 - 20 Aug 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report date:
2004

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: Algal Growth Inhibition Test stipulated in the "Testing Methods for New Chemical Substances" (No. 031121002, Environmental Policy Bureau, Ministry of the Environment).
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
459-520-5
EC Name:
-
Cas Number:
132182-92-4
Molecular formula:
Hill formula: C7H3F13O CAS formula: C7H3F13O
IUPAC Name:
1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Sumitomo 3M Ltd, lot #1
- Purity: 99.96%
- Synonyms: T-7869
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: negative control and test substance solutions, taken at start of test and at 24-hour intervals thereafter.
- Sampling method: Samples of new solution were taken from an additional flask processed in the same way as the exposure flasks. For other time points, equal volumes of test solution were taken from the test flasks and combined.
- Sample storage conditions before analysis: No

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Aliquots of test substance were added directly to growth medium in test vessels at loading rates of 500, 1000, and 2000 µL/L. Solutions were then stirred ca. 48 hours to equilibrate test solutions and vapor phase.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): At preparation, test solutions were clear and colorless.

CONCENTRATION OF TEST SUBSTANCE IN TEST MEDIUM:
To establish range of expected test substance concentrations in this study, triplicate 500 mL flasks were filled with growth medium and treated with test substance at a loading rate of 50 µL/L. Flasks were stirred for 24 and 48 hours at the test temperature (23 ± 1 °C). After settling for one hour, triplicate samples were taken from the middle of the flasks, and then pretreated and analyzed as described in the section on analytical method. The overall mean after 48 hours was 0.478 mg/L.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Strain: ATCC 22662
- Source (laboratory, culture collection): Internal stock originally obtained from American Type Culture Collection 30 Jun 1995
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: propagation under same conditions as the test. Sterility maintained throughout.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Test temperature:
22.9 - 23.8 °C
pH:
Starting pH: 8.0 - 8.1
Ending pH: 9.5 - 10.2
Nominal and measured concentrations:
See Table 1
Details on test conditions:
TEST SYSTEM
- Test vessel: 500 mL glass Erlenmeyer flask with airtight seal, 100 mL fill volume
- Type: closed
- Aeration: No
- Initial cells density: 10,000 cells/mL
- Control end cells density: 418,000 cells/mL
- No. of vessels per concentration: three vessels
- No. of vessels per control: six vessels

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: OECD medium, modified by ferric chloride trihydrate increase from 0.0640 mg/L to 0.080 mg/L

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: 102 - 109 µE/m²∙s

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Coulter Z1 particle counter, at 24-hour intervals
- Other: microscopic examination at 72-hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2X
- Justification for using less concentrations than requested by guideline: No toxicity in rangefinder done at a loading rate of 1000 µL/L.
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.404 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: No effect on growth rate observed in saturated solutions
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 0.404 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: No effect on growth rate observed in saturated solutions
Details on results:
Test substance concentrations are shown in Table 1. Concentrations declined by 67% - 81% within 24 hours, but remained relatively stable thereafter. Loading rates were well above the test substance's stated water solubility and the maximum attainable medium concentration (0.478 mg/L).
Results with reference substance (positive control):
A 72-hour acute toxicity test of potassium dichromate was done as part of regular quality checks around the time of this test. The EC50 (biomass) was 0.376 mg/L. This was within the control range 0.375 ± 0.096 mg/L, where range is twice the standard deviation.

Any other information on results incl. tables

Table 2, Cell counts (x 104cells/mL) during the algae toxicity test

Mean concentration

T = 0 hour

T = 24 hour

T = 48 hour

T = 72 hour

Control

1.00

3.45

14.7

42.1

 

1.00

3.36

14.4

42.5

 

1.00

3.45

14.6

41.5

 

1.00

3.56

14.8

44.7

 

1.00

3.47

15.7

40.6

 

1.00

3.64

14.4

39.7

Mean

1.00

3.49

14.8

41.8

SD

0

0.0984

0.482

1.72

0.122 mg/L

1.00

3.45

13.4

40.8

 

1.00

3.40

15.4

42.6

 

1.00

3.54

13.7

40.4

Mean

1.00

3.46

14.1

41.3

SD

0

0.0733

1.07

1.13

0.204 mg/L

1.00

3.44

14.4

44.3

 

1.00

3.31

12.8

33.0

 

1.00

3.74

14.1

36.9

Mean

1.00

3.50

13.7

38.0

SD

0

0.217

0.852

5.72

0.404 mg/L

1.00

3.51

14.1

46.2

 

1.00

3.36

10.5

40.5

 

1.00

3.68

13.9

39.1

Mean

1.00

3.52

12.8

41.9

SD

0

0.164

2.04

3.74

Table 3. Growth rates (1/day) during the algae toxicity test.

Mean concentration

T = 0-24 hour

T = 24-48 hour

T = 48-72 hour

T = 0-72 hour

Control

1.24

1.45

1.05

1.25

 

1.21

1.46

1.09

1.25

 

1.24

1.44

1.04

1.24

 

1.27

1.42

1.11

1.27

 

1.24

1.51

0.95

1.23

 

1.29

1.38

1.01

1.23

Mean

1.25

1.44

1.04

1.24

SD

0.028

0.044

0.056

0.122 mg/L

1.24

1.36

1.11

1.24

 

1.22

1.51

1.02

1.25

 

1.26

1.35

1.08

1.23

Mean

1.24

1.41

1.07

1.24

SD

0.020

0.090

0.049

0.204 mg/L

1.24

1.43

1.12

1.26

 

1.20

1.35

0.95

1.17

 

1.32

1.33

0.96

1.20

Mean

1.25

1.37

1.01

1.21

SD

0.062

0.055

0.098

0.404 mg/L

1.26

1.39

1.19

1.28

 

1.21

1.14

1.35

1.23

 

1.30

1.33

1.03

1.22

Mean

1.26

1.29

1.19

1.24

SD

0.045

0.131

0.158

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
validity criteria from OECD201: control biomass increase >16x (41x), CV for section-by-section growth rates <35% (16%), CV for average specific growth rates <7% (1.2%)
Conclusions:
HFE s-601 is not toxic at the limit of water solubility (OECD 201).
Executive summary:

The toxicity of HFE s-601 to algae was assessed according to OECD TG 201. Water soluble fractions were prepared at loading rates of 500, 1000 and 2000 µL/L (ca. 0.8, 1.7, and 3.3 g/L). Test vessels were sealed 500 mL Erlenmeyer flasks containing 100 mL of growth medium. Measured test substance concentrations declined ca. 67 - 81% in the first 24-hour period but were relatively stable thereafter. Overall test substance concentration was reported as a time-weighted average. No effect on growth rate was observed relative to control.  The EC50 of HFE s-601 to Pseudokirchneriella subcapitata was >0.404 mg/L (saturated solution), with a corresponding NOEC ≥0.404 mg/L.

The test was conducted under GLP in accord with internationally accepted test guidelines, with analytical confirmation of test substance concentration. Therefore, this test is considered reliable with restrictions and is suitable for Risk Assessment, Classification & Labeling, and PBT Analysis.

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