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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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:
February 2 to 25, 2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well documented study performed according to OECD Guideline and GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2-hexyldecan-1-ol
EC Number:
219-370-1
EC Name:
2-hexyldecan-1-ol
Cas Number:
2425-77-6
Molecular formula:
C16H34O
IUPAC Name:
2-hexyldecan-1-ol
Details on test material:
- Name of test material: 2-hexyl-1-decanol
- Substance type: pure active substance
- Physical state: liquid
- Analytical purity: 98.6 %
- Lot/batch No.: 03507
- Expiration date of the lot/batch: 2012-04-01
- Storage condition of test material: room temperature, protected from moisture and light

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: all test concentrations and control, separate replicates or the test item were prepared (test beginning provided without alga and test end with same density of alga as the test replicates) and incubated under test conditions, additionally the highest test concentration without algae was analysed after 72 hours
- Sampling method: 1 L of all samples (except the additional sample prepared and incubated without algae) were extracted with 10 mL n-Hexane. 400 mL of the additional sample were filled up to 500 mL with demineralised water and then extracted with 5 mL n-Hexane. From each sample 300 µL extract were mixed with 150 µL MSTFA (N-Methyl-N-(trimethylsilyl)trifluoroacetamide) and derivatised in a waterbath (50°C) for 1 hour. Afterwards the solutions were evaporated to dryness, filled up to 3 mL with CH2Cl2 : n-Hexane (50 : 50) and analysed.
- Sample storage conditions before analysis: stored at 6 +/- 2 °C until start of analysis, if necessary

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A saturated solution was prepared with dilution water (loading: 2 mL test item/L). The test item was placed on the surface of the dilution water in a closed bottle and slowly stirred for 7 days (the formation of an emulsion was avoided).
- Controls: dilution water
- Evidence of undissolved material (e.g. precipitate, surface film, etc): nothing mentioned

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Green alga
- Strain: Pseudokirchneriella subcapitata HINDAK, SAG 61.81
- Source (laboratory, culture collection): Sammlung von Algenkultutren (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Germany
- Age of inoculum (at test initiation): a four day old preculture was used
- Method of cultivation: fresh stocks were prepared every month on Z-Agar, light intensity amounted 35 - 70 µE/m²s for 24 h per day

ACCLIMATION
- Acclimation period: 4 days
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: no (microsopic evaluation at start and end of the incubation period)

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
n.a.

Test conditions

Hardness:
0.24 mmol Ca+Mg/L
Test temperature:
22 - 23 °C
pH:
Start 0 h: 7.72
End 72 h: 8.00
Dissolved oxygen:
no data
Salinity:
freshwater test according to guideline
Nominal and measured concentrations:
Nominal: 6.25, 12.5, 25 , 50 and 100 % of saturated solution (WAF)
Measured: 11.3, 5.15 µg/L (geometric mean); only the two highest test concentration solutions could be measured, the lower concentrations were below the LOQ and were calculated from the geometric mean measured for the two highest dilution levels of 50 and 100 %
Calculated concentrations: 2.57, 1.29 and 0.643 µg/L
Details on test conditions:
TEST SYSTEM
- Initial cells density: 5087 cells/ml
- Control end cells density: 1755439 cells/ml (mean)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

TEST MEDIUM
- Dilution water: according to OECD test guideline 201

OTHER TEST CONDITIONS
- Photoperiod: 24 h/d light
- Light intensity and quality: 60 - 120 µE/m²s (corresponding to 4440 - 8880 Lux); mean value: 72.9 µE/m²s

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell desnity: chlorophyl-a-fluorescence, excitation at 436 nm, emission at 685 nm
- Measurement intervall: at 0, 24, 48 and 72 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 0.01, 0.1, 1, 10 and 100 % saturated solution
- Results used to determine the conditions for the definitive study:
at 100% saturated solution: 11% specific growth rate inhibition/42 % yield inhibition;
at 10% saturated solution: -3% specific growth rate inhibition/-18 % yield inhibition
Reference substance (positive control):
yes
Remarks:
potassium dichromate (experimental date September 21 to 24 2009)

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 11.3 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 11.3 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
11.3 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 5.15 - < 11.3 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: inhibition of yield
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 11.3 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: inhibition of yield
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
5.15 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: inhibiton of yield
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
11.3 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: inhibition of yield
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Adherence to test vessels: no
- Aggregation of algal cells: no
- Any stimulation of growth found in any treatment: no (slight increase of growth rate in lower concentrations, but within coefficient of variation of average growth in replicate control cultures)
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: n.a.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- ErC50: 0.82 mg/l/72h
- EyC50: 0.37 mg/l/72h
Reported statistics and error estimates:
Statistics performed (One way analysis of variance) by Normality Test (Kolmogorov-Smirnov) and Equal Variance Test, tested for NOEC/LOEC of growth rate and yield:
The differences in the mean values among the treatment groups were not great enough to exclude the possibility that the difference is due to random sampling variability; there were no statistically significant differences.

Any other information on results incl. tables

Table 1: Cell densities
Geometric mean
test item concentrations
[µg/L]
Cell density x 104
[cells/mL]
  0 h 24 h 48 h 72 h
control 0.51 1.75 17.71 175.54
0.643
(calculated)
0.51 1.95 19.73 193.46
1.29
(calculated)
0.51 1.68 18.4 184.05
2.57
(calculated)
0.51 1.63 18.16 177.32
5.15
(measured)
0.51 1.73 19.36 175.86
11.3
(measured)
0.51 1.44 15.03 146.42
Table 2: Evaluation after 72 h
Geometric mean
test item concentrations
[µg/L]
Growth rate
[d-1]
Rate-related inhibition
[%]
Yield x 104
[cells/mL]
Inhibition of yield
[%]
control 1.94 - 175.04 -
0.643
(calculated)
1.98 -1.97 192.95 -10.2
1.29
(calculated)
1.96 -1.10 183.54 -4.85
2.57
(calculated)
1.95 -0.47 176.82 -1.01
5.15
(measured)
1.95 -0.33 175.35 -0.18
11.3
(measured)
1.89 2.95 145.91 * 16.6
* = biologically significant
negative inhibitions = increase of growth

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
No significant inhibiting effects on specific growth rate and yield were found when tested with the saturated solution. The EC50-values for specific growth rate inhibition (ErC50) and inhibition of yield (EyC50) after 72 h were > 11.3 µg/L (saturated solution).
All effect levels were given based on intial measured and calculated concentrations of 2-Hexyl-1-decanol.
Executive summary:

In this study the effects of the test item 2-Hexyl-1-decanol on the growth of the freshwater green alga Pseudokirchneriella subcapitata were tested. No significant inhibiting effects on specific growth rate and yield were found when tested with the saturated solution. The EC50-values for specific growth rate inhibition (ErC50) and inhibition of yield (EyC50) after 72 h were > 11.3 µg/L (saturated solution). All effect levels were given based on intial measured and calculated concentrations of 2-Hexyl-1-decanol.

The study was conducted according to OECD-Guidline 201 for Testing of Chemicals: "Alga, Growth Inhibition Test", adopted March 2006 and under the conditions of GLP.