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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:
From 2011-05-27 to 2011-06-31
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The reliability is rated 2 because the study followed a standard guideline of reference (OECD 201), which describes a procedure designed to evaluate this endpoint. The results were reviewed f or reliability and assessed as valid. However the study was not conducted under GLP condition.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
tetrakis{9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium} C12-(branched and/or linear)-alkyl-(4-sulfonatophenoxy)benzenesulfonate and oxybis[C12-(branched and/or linear)-alkyl-benzenesulfonate]
EC Number:
700-761-5
Molecular formula:
not applicable
IUPAC Name:
tetrakis{9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium} C12-(branched and/or linear)-alkyl-(4-sulfonatophenoxy)benzenesulfonate and oxybis[C12-(branched and/or linear)-alkyl-benzenesulfonate]
Details on test material:
- Name of test material (as cited in study report): Sepisol Fast Red SN
- Substance type: Organic salt - UVCB
- Physical state: red/magenta powder
- Lot/batch No.: 029244
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Water solubility: 2 mg/L

Sampling and analysis

Analytical monitoring:
no

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:CCAP278/2
- Source (laboratory, culture collection): SAMS research Services, Ltd, Scotland
- Age of inoculum (at test initiation): culture in exponential growth phase after 3 days in a pre-culture in the medium test.
- Method of cultivation: Culture medium : LC-Oligo (pH 7,1 +/- 0,1). Temperature of 21-24 °C. 16h light/8h dark (around 4500 lux). Bubbling aeration.

Study design

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

Test conditions

Test temperature:
22 - 22.1 °C
pH:
at t0 = 7.7 to 8.1
at t72h = 7.5 to 8.9
Nominal and measured concentrations:
Nominal concentrations: 0, 0.17, 0.30, 0.56, 1.0, 2.0 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Flask
- Material, size, headspace, fill volume: flask of 30 mL with 20 mL of the test solution
- Aeration: none
- Type of flow-trough (e.g. peristaltic or proportional diluter): static
- Renewal rate of test solution (frequency/flow rate): none
- Initial cells density: around 10^4/mL
- No. of vessels per concentration (replicates): triplicate
- No. of vessels per control (replicates): sextuplicate

GROWTH MEDIUM
- Standard medium used: yes (from OECD guideline 201)

OTHER TEST CONDITIONS
- Photoperiod: constante (24h/24h)
- Light intensity and quality: day light (400-700 nm), around 7500 lux (equivalent to 55 µE.m-².s-1)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Malassez counting chamber

TEST CONCENTRATIONS
- Spacing factor for test concentrations: between 1.8 and 2
- Test concentrations: 0, 0.17, 0.30, 0.56, 1.0 and 2.0 mg/l
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
1.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: (95% CI 1.3-1.5)
Duration:
72 h
Dose descriptor:
EC20
Effect conc.:
0.69 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: (95% CI 0.60-0.76)
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.46 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: (95% CI 0.38-0.53)
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test):no
- Any stimulation of growth found in any treatment: no
Results with reference substance (positive control):
- EC50 72h: 1.08 mg/L
- Results with reference substance valid? Yes. The EC50 72h values falls within the acceptable range of 0.92 mg/L and 1.46 mg/L (as defined by the NF EN ISO 8692-2005 )
- Other: reference substance: Potassium dichromate
Reported statistics and error estimates:
- CEx% calculated using the Hill Equation (macro Regtox_ev 6.6.2xls).
- NOEC calculated using the T-test of Bonferroni (Toxcalc software).

Any other information on results incl. tables

Results

At T=72h

Concentration

mg/L

Cells concentration x 106

 

 

1

2

3

4

5

6

Average cells number

Cells inhibition

0

4.62

5.32

6.28

5.38

4.96

4.76

5.22

 

0.17

5.38

5.42

5.76

 

 

 

5.52

-6%

0.30

6.44

6.46

6.30

 

 

 

6.40

-23%

0.56

2.68

3.06

2.78

 

 

 

2.84

46%

1

0.44

0.46

0.51

 

 

 

0.47

91%

2

0.09

0.10

0.09

 

 

 

0.09

98%

 

Growth Rate

 

 

 

1

2

3

4

5

6

Growth rate inhibition

Inhibition

0

2.05

2.09

2.15

2.10

2.07

2.06

2.08

 

0.17

2.10

2.10

2.12

 

 

 

2.10

-1%

0.30

2.16

2.16

2.15

 

 

 

2.15

-3%

0.56

1.86

1.91

1.88

 

 

 

1.88

10%

1

1.26

1.27

1.31

 

 

 

1.28

39%

2

0.71

0.75

0.73

 

 

 

0.73

65%

Validation criteria:

* Average growth rate for the control at 72 hours : 2.08 j-1 (> 0.92 j-1)

* Coefficient of variation of average specific growth rates during the whole test period in replicates control cultures : 1.6% (< 7%)

* The pH of the control medium did not increase by more than 1.5 units during the 72h period. (+0.7 pH units)

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the experimental conditions:
72h - EC50 = 1.4 mg/L (1.3 - 1.5 mg/L)
72h - NOEC = 0.30 mg/L
Executive summary:

The acute algal toxicity test for the substance Sepisol Fast Red SN was carried out to determine the ecotoxicological profile of the test substance against an unicellular green algae. The test organism Pseudokirchnerella subcapitata was used and the OECD guideline 201 (2006) was followed.

 

The median effective concentrations (EC50) and the non-observed effect concentration 72h (72h-NOEC) values with regard to the growth rate (ErC) were determined.

The following nominal concentrations were tested: 0.17, 0.30, 0.56, 1 and 2 mg/L.

 

A solution was prepared by diluting 2 mg of test material in 1 liter of the assay medium. No solvents were used to facilitate the dispersion of the test item.

 

Each concentration and control were inoculated with approximately 10 000 cells per mL. The test was carried out over 72 hours at a temperature of 22°C to 22.1°C under constant stirring (250 rev/min).

Each vessel concentration was tested 3 times. 6 controls were run with the same experimental condition. Algal concentration was counted using a Mallassez counting chamber.

Validation experiments and the precultivation ensured that the algal were of appropriate vialibility and susceptibility.

 

Under the experimental conditions:

    * 72h - EC10 = 0.46 mg/L (0.38 - 0.53 mg/L)

    * 72h - EC20 = 0.69 mg/L (0.60 - 0.76 mg/L)

    * 72h - EC50 = 1.4 mg/L (1.3 - 1.5 mg/L)

    * 72h NOEC = 0.30 mg/L