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Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was conducted in conformance to GLP and on the basis of EU Method C.3 (Algal Inhibition test) Cited as Directive 92/69/EEC, C.3
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Version / remarks:
Cited as Directive 92/69/EEC, C.3
GLP compliance:
yes
Analytical monitoring:
yes
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Desmodesmus subspicatus
- Strain: Desmodesmus subspicatus
- Source (laboratory, culture collection): Institute of Plant Physiology at the University of Göttingen, (Germany)


ACCLIMATION
Set up three days before test started; grown under identical exposure conditions except from the use of a different nutrient medium
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 d
Test temperature:
23 +/- 2 °C
pH:
7.9 - 10.6
Nominal and measured concentrations:
100 mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel:300 ml Erlenmeyer flasks with stoppers
- Control end cells density: cell density 10 E+4 cells/ml
- No. of vessels per concentration (replicates):3 (concentration), 6 (control)

OTHER TEST CONDITIONS
- Adjustment of pH: 7.9 - 10.6 (at test start, after 72 h)
- Photoperiod:continuous uniform illumination (spectral range 400 to 700 nm)
- Light intensity and quality: 60 - 120 µE x mE-2 x sE-1
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : growth rate
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]: Microcellcounter Sysmex F-300 (Digitana)

TEST CONCENTRATIONS
1 (100 mg/l) plus 1 control
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
growth rate, biomass
Duration:
72 h
Dose descriptor:
EC0
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
growth rate, biomass
EC0 (growth rate) was determined as >= 100 mg/L and EC50 (growth rate) was determined as >100 mg/L in a limit test with Desmodesmus subspicatus. No effects were observed in the study.
Conclusions:
EC0 (growth rate) was determined as >= 100 mg/L and EC50 (growth rate) was determined as >100 mg/L in a limit test with Desmodesmus subspicatus. No effects were observed in the study.
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: 2b Guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
not specified
Details on test solutions:
1000 mg of the test item was solved in 1000 mL growth medium by magnetic strirring on the day of the test start. The stock solution (1000 mg/L) was diluted with growth medium in order to prepare the test solutions.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The inocculum is taken from Toxicon's culture of P. subcapitata (NIVA CHL 1), which originates from NIVA, Oslo, Norway. A qualification test on the alga culture was made on the 5th of June 2008 to assure teh quality of the test animals. EvC50 was 1.5 mg/L, which confirmed that the culture was suitable as a test organism according to OECD TG no. 201.
Test type:
not specified
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
not applicable
Hardness:
no data
Test temperature:
21 - 24 +/- 2 °C
pH:
controls: 8.11
tests - start: 7.79 - 7.8.11
tests - finish: 7.61 - 7.78
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
Nominal concentrations: 1000, 500, 250, 125, 62.5, 31.2, 15.6 mg/L
Measured concentartions: No analysis
Details on test conditions:
The nutrient concentration in the growth media was the same in all test solutions and in the controls, and the composition was as specified in Annex 3 ("Preparation of OECD medium") in OECD TG 201. For each test concentration, triplicates were used and for the controls six replicates were used. Test bottles were 250 mL glass E-bottles with 100 mL solution that were incubated on a shaking table with approximately 100 µE m-2 s-1 continuous illumination at a temperature of 21-24 +/- 2 °C. The pH was measured in the controls and in one replicate of each concentration at the start of the experiment. The pH was again measured in the same replicates after 72 hours. The incubation period was 72 hours with sampling at 0, 24, 48 and 72 hours. As a measurement of the biomass in the samples, the number of cells/mL was counted by microscope The nominal concentration of the test item in the test solutions were: 1000, 500, 250, 125, 62.5, 31.2, 15.6 g/L.
Reference substance (positive control):
not specified
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
31 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
64 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC20
Effect conc.:
74 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
106 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
31 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
45 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC20
Effect conc.:
55 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
84 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
The effects of the test substance on the growth of algae were determined by two response variables:
a) Average specific growth rate: This response variable is calculated on the basis of the logarithmic increase of biomass during the test period, expressed per day.
b) Yield: This response variable is the biomass at the end of the test minus the starting biomass.
Results with reference substance (positive control):
no data
Reported statistics and error estimates:
The EC value is calculated by means of graphic interpolation. The NOEC-value is the highest tested concentration not statistically different from the controls (Mann- Whitney U-Test p>0.05).

For each test concentration, triplicates were used and for the controls six replicates were used.

Table: Calculated response variables for each treatment group and the control group (mean +/- coefficient of variation) after 72 hours exposure for the test item Polyol R3530.

  72 h
Specific growht rate (µ)
Mean ± CV (%)
72 h
Yield (cells/mL)
Mean ± CV (%)
Control 1.27 ± 2.8 446667 ± 11.6
15.6 mg/L 1.29 ± 5.9 473333 ± 23.4
31.2 mg/L 1.28 ± 0.6 460000 ± 2.2
62.5 mg/L 1.16 ± 8.8 326667 ± 28.4
125 mg/L 0.41 ± 38.9 26667 ± 57.3
250 mg/L 0.00 ± 0.00 0.00 ± 0.00
500 mg/L 0.00 ± 0.00 0.00 ± 0.00
1000 mg/L 0.00 ± 0.00 0.00 ± 0.00
Validity criteria fulfilled:
yes
Conclusions:
Toxicity to aquatic algae and cyanobacteria was determined with Pseudokirchneriella subcapitata according to OECD method no. 201 and gave an 72 hour-ErC50 = 106 mg/L and a 72 hour-NOEC = 31 mg/L, each based on the growth rate (Toxicon AB, 2008).
Executive summary:

Toxicity to aquatic algae and cyanobacteria was determined with Pseudokirchneriella subcapitata according to OECD method no. 201 and gave a 72 hour-ErC50 = 106 mg/L and a 72 hour-NOEC = 31 mg/L, each based on the growth rate (Toxicon AB, 2008).

Description of key information

72 hr ECr50 (Desmodesmus subspicatus) > = 100 mg/l.

72 hr NOEC (Desmodesmus subspicatus) > = 100 mg/l.

72 hr ECr50 (Pseudokirchnerella subcapitata) = 106 mg/l.

72 hr NOEC (Pseudokirchnerella subcapitata) = 31 mg/l.

Key value for chemical safety assessment

Additional information

Toxicity to algae and cyanobacteria has been tested with Desmodesmus subspicatus over a 72 hr period at 100 mgl/l. No effects were observed and the NOEC and the EC0 (biomass and growth rate) are > = 100 mg/l. Furthermore a test with Pseudokirchnerella subcapitata is available. The 72 hr ECr50 (Pseudokirchnerella subcapitata) = 106 mg/l and the 72 hr NOEC (Pseudokirchnerella subcapitata) = 31 mg/l.