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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:
24 Nov 2006 - 15 Dec 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II)
Version / remarks:
The pH of the alga medium at the start of the definitive test was 7.1, prior to alga inoculation. This value is outside of the recommended limits stated within the OPPTS test guideline, of pH 7.4 – 7.6. It is the opinion of the Study Director, that although the pH is outside of this range, the test species will still thrive at the test media pH of 7.1. This is further supported by the test species satisfying the OPPS test guideline (850.5400) recommendation of achieving at least 3.5x10^6 alga cell/mL in the control treatment at the 96 hours.
Deviations:
yes
Remarks:
This deviation in alga medium pH is not considered to have affected the integrity of the study.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 09898602
- Expiration date of the lot/batch: >6 month from receipt date 25°C
- Date received: 6 Nov 2006
- Physical Appearance: colourless liquid
- Purity: 99.8%
- Storage: refrigerated, 1-10°C

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: 278/4
- Source (laboratory, culture collection): Culture Collection of Algae and Protazoa SAMS Research Services Ltd., Obam, UK
- Age of inoculum (at test initiation):
- Method of cultivation:

ACCLIMATION
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Remarks on exposure duration:
24, 48, 72 and 96 h sampling

Test conditions

Test temperature:
23.6 - 24.3°C
pH:
7.1 - 9.7
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer (conical) flask
- Volume: 250mL

- Initial cells density: 1x10^4cells/mL
- Control end cells density:
- No. of vessels per concentration (replicates):
- No. of vessels per control (replicates):

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes

- Photoperiod: 24h light
- Light intensity and quality: 4000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter
- intervals: sampling at 24, 48, 72 and 96h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: N/A
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
2.7 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
0.941 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
0.625 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: NOEC (biomass) is also 0.625 mg/L
Details on results:
No algal cell morphology differences were observed when comparing with samples of algal cell at each treatment with control samples, with exception that cells were paler in colours with increasing concentration.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test item was considered to be toxic to P. subcapitata at measured concentrations up to 12.9 mg/L as significant growth inhibition relative to the control treatment was observed.