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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:
06 - 09 Jun 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report Date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Version / remarks:
2011
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Staatliches Gewerbeaufsichtsamt Hildesheim

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Sampling and analysis

Analytical monitoring:
yes
Remarks:
TOC
Details on sampling:
- Concentrations: All test item concentrations and the control - Sampling method: according to DIN EN 1484 at the start and the end of the exposure

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION - Method: 20 mg test item/L were freshly prepared with dilution water. This stock solution was used to achieve the required test item concentrations.- Evidence of undissolved material: stock solution was agitated until the solution was visually clear

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM - Common name: green algae - Strain: Pseudokirchneriella subcapitata SAG 61.81 - Source: Sammlung von Algenkulturen (SAG) Pflanzenphysiologisches lnstitut der Universitat Gottingen Nikolausberger Weg 18, D-37073 Gottingen, Germany - Age of inoculum: A three days old preculture, was used as inoculum - Method of cultivation: Fresh stocks are prepared every month on Z-Agar. Light intensity amounted to 35-70 μE m-2 s-1 for 24 h per day

Study design

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

Test conditions

Hardness:
0.24 mmol Ca+mg/L
Test temperature:
22.0 - 23.0 °C (mean 22.5 °C)
pH:
7.93 - 8.95 (control)7.73 - 8.95 (test item concentration)
Nominal and measured concentrations:
Control, 0.200, 0.632, 2.00, 6.32 and 20.0 mg/L (nominal)
Details on test conditions:
TEST SYSTEMTest vessel: - Type: open - Material, size, headspace, fill volume: Sterile Erlenmeyer flasks (vol. 250 ml) with cotton wool plugs, 100 mL test volume - Aeration: Test containers were placed on a rotary shaker and oscillated at approximately 70 rpm - Initial cells density: approximately 5 x 10 E+03 - 10^4 cells/mL (corresponds to 6305 cells/mL) - Control end cells density: 1375608 cells/mL - No. of vessels per concentration (replicates): 3 - No. of vessels per control (replicates): 6 GROWTH MEDIUM - Standard medium used: yes TEST MEDIUM / WATER PARAMETERS - Source/preparation of dilution water: according to OECD guideline - Culture medium different from test medium: no - Intervals of water quality measurement: pH was measured at test start and test end, Temperature was measured continously and light intensity was measured prior to test start OTHER TEST CONDITIONS - Sterile test conditions: yes - Photoperiod: 24 hours/day light - Light intensity and quality: approx 4440 to 8880 lux, corresponding to 60 to 120 μE*m-2*s·-1, fluorescent tubes, OSRAM L 36 W/865, cool daylight, within ± 15 % over incubation area - Incubation: The flasks were positioned randomly and repositioned daily EFFECT PARAMETERS MEASURED: cell density via fluorescence - Determination of cell concentrations: Fluorometer: Microplate Reader Chameleon V (HIDEX) with Software Micro Win 4.41 (MIKROTEC LABORSYSTEME GMBH) - Chlorophyll measurement: measured daily via Chlorophyll a fluorescence, excitation at 436 nm, emission at 685 nm TEST CONCENTRATIONS - Spacing factor for test concentrations: dilution factor of √10Range finding study - Test concentrations: Control, 1.00, 10.0 and 100 mg/L - Results used to determine the conditions for the definitive study: The concentration range of the main test was based on the results of the range-finding test
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrations
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
6.47 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% Confidence Intervals
Remarks:
6.34 - 6.60 mg/L
Details on results:
- Exponential growth in the control (for algal test): yes - Observation of abnormalities (for algal test): Microscopic evaluation of the cells at the start and end of exposure revealed no morphological abnormalities.
Results with reference substance (positive control):
- ErC50: 0.564 mg/L

Any other information on results incl. tables

Table 1: Biological Results: NOEC, LOEC, EC-values and 95% Confidence Intervals of the test item (0 - 72 hours) based on nominal test item concentrations [mg/L]

 

Growth Rate Inhibition

Nominal test item concentration [mg/L]

NOEC

0.632

LOEC

2.00

ErC10

2.82 (2.59 - 3.06)

ErC20

3.82 (3.61 - 4.02)

ErC50

6.47 (6.34 - 6.60)

 

Yield Inhibition

Nominal test item concentration [mg/L]

NOEC

0.632

LOEC

2.00

EyC10

1.65 (1.38 - 1.91)

EyC20

2.01 (1.78 - 2.29)

EyC50

2.99 (2.63 - 3.58)

Table 2: Analytical Results: TOC Content of the Test Media at the Start and the End of the Exposure

Nominal Test Item Concentration [mg/L]

TOC [mg C/L]

Test start (without algae), 0 hours

Test end (without algae), 72 hours

20.0

11.6

12.3

6.32

2.54

5.45

2.00

< 2.00

2.63

0.632

< 2.00

< 2.00

0.200

< 2.00

< 2.00

Control

< 2.00

< 2.00

Limit of quantification = 2.00 mg C/L

Table 3: EC50-Values of the Reference Item based on nominal concentrations [mg/L], (0-72 hours)

 

Current Study

Valid Range (average ± 3 x SD)

 

Growth Rate inhibition

ErC50

0.564

0.797 ± 0.428

95 % confidence interval

0.546 - 0.582

 

Yield inhibition

EyC50

0.322

0.415 ± 0.275

95 % confidence interval

0.239 - 0.342

SD = Standard deviation

Applicant's summary and conclusion

Validity criteria fulfilled:
yes