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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011-08-19 to 2011-09-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study performed according to internationally accepted test guidelines for toxicity to algae (OECD 201) and conform CLP requirements.
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: PFW100113
- Expiration date of the lot/batch: 2012-12-01
- Analytical purity: 99.3 %
- Impurities (identity and concentrations): not reported

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark
- Stability under test conditions: not reported

OTHER SPECIFICS:
- Name of test material (as cited in study report): DMDEE (Morpholine, 4,4'-(oxydi-2,1-ethanediyl)bis-)
- Substance type: pale yellow liquid
- Physical state: liquid
Analytical monitoring:
yes
Details on sampling:
- Concentrations: control and 100 mg/l
- Sample storage conditions before analysis: all 0-hour samples (and duplicate 72-hour samples) stored at approximately -20 °C prior to analysis
Vehicle:
no
Details on test solutions:
- 100 mg of test item was dissolved directly in culture medium and the volume adjusted to 1 litre to give a 100 mg/l stock solution
- stock solution was inoculated with algal suspension (13.2 ml) to give the required test concentration of 100 mg/l
- all solutions were inverted several times to ensure adequate mixing and homogeneity
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: freshwater alga
- Strain: CCAP 278/4
- Source (laboratory, culture collection): Culture collection of algae and protozoa (CCAP-, SAMS Research services Ltd., Scottish Marine Institute, Oban, Argyll, Scotaland
- Method of cultivation:
* in culture medium (replenished periodically)
* under constant aeration
* illumination at 21 ± 1°C

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Hardness:
Not reported.
Test temperature:
24 ± 1 °C
pH:
at initiation of test: 8.0 in control and 8.3 in 100 mg/l
after 72 hours exposure: 8.3 in control and 8.0 in 100 mg/l
Dissolved oxygen:
Not reported.
Salinity:
Not applicable.
Nominal and measured concentrations:
nominal concentrations: 0 and 100 mg/l
measured concentrations:
Details on test conditions:
TEST SYSTEM
- Test vessel: conical flasks
- Type (delete if not applicable): closed: plugged with polyurethane foam bungs
- Material, size, headspace, fill volume: glass, 250 ml, headspace not defined, 100 ml
- Aeration: no, closed system to prevent evaporation
- Initial cells density and culture preparation: 5 x 10E+03 cells per ml
- Control end cells density: mean from six replicates: 9.28E+05 cells per ml
- No. of vessels per concentration (replicates): six
- No. of vessels per control (replicates): six
- constantly shaken at approximately 150 rpm for 72 hours
- incubation in INFORS Multitron® Version 2 incubator

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water (Elga optima 15+ or Elga Purelab Option R-15 BP)
- Culture medium different from test medium: no
- Intervals of water quality measurement: at test initiation and 72h

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH of culture medium: yes, to 7.5 ± 0.1 with NaOH or HCl
- Photoperiod: continuous lighting
- Light intensity and quality: 7000 lux, warm white lighting (380-730 nm)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: cell densities were measured using a Coulter® Multisizer Particle Counter at 0, 24, 48 and 72 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test
- Range finding study:
* Test concentrations: 0.10, 1.0, 10, 100 mg/l
* Results used to determine the conditions for the definitive study: no effect on growth at the test concentrations of 0.10, 1.0, 10 and 100 mg/l
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
- Colour differences: at start of test all control and test cultures were observed to be clear colourless solutions. After the 72-h test period all control and test cultures were observed to be pale green dispersions.
Results with reference substance (positive control):
- ErC50(72h): 1.32 mg/l, 95% C.I.: 0.98-1.4 mg/l
- EyC50(72h): 0.48 mg/l, 95% C.I.: 0.43-0.54 mg/l
- NOEC based on growth rate: 0.25 mg/l
- LOEC based on growth rate: 0.50 mg/l
- the results were within the normal ranges for this reference item
Reported statistics and error estimates:
Differences between the control and 100 mg/l groups were tested by means of a Student's t-test incorporating Bartlett's test for homogeneity of variance (Sokal and Rohlf 1981).
There were no statistically significant differences (p >= 0.05), between the control and 100 mg/l test group.
Validity criteria fulfilled:
yes
Conclusions:
In this study, the freshwater algae Pseudokirchnierielle subcapitata was exposed to 100 mg/l of test substance for 72 hours. Based on the growth rate, the EC50 was determined to be > 100 mg/l and the NOEC was 100 mg/l.

Description of key information

The key value for acute toxicity of algae was obtained from a study exposing Pseudokirchnerella subcapitata to a single concentration of the test substance during 72 hours under GLP conditions and according to OECD 201.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

The well-designed growth inhibition study (Klimisch 1) was performed by Harlan Laboratories (Vryenhoef and Mullee, 2011). Pseudokirchnerella subcapitata was exposed to 100 mg/l of test substance during 72 hours and growth rate was monitored. The ErC50(72h) of > 100 mg/l and NOEC of 100 mg/l was found.