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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 2014-08-05 to 2014-08-22
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 203), which describes a procedure designed to evaluate this endpoint. The results were reviewed for reliability and assessed as valid. However, the study was not conducted under GLP conditions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report date:
2014

Materials and methods

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

Test material

Constituent 1
Reference substance name:
914-151-0
IUPAC Name:
914-151-0
Details on test material:
- Name of test material (as cited in study report): Jaune MG DPG
- Substance type: Organic salt

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
- 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 - 22.6 °C
pH:
at t0 = 7.4 to 8.0
at t72h = 7.4 to 8.3
Nominal and measured concentrations:
Nominal concentrations: 2.1, 4.0, 7.7, 14.6, 27.7 and 52.6 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): 6 replicates
- No. of vessels per control (replicates): 6 replicates

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: around 1.9
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
15.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: (95% CI 15.2 - 16.4)
Duration:
72 h
Dose descriptor:
other: ErC20
Effect conc.:
11.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: (95% CI 10.8 - 12.4)
Duration:
72 h
Dose descriptor:
other: ErC10
Effect conc.:
9.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: (95% CI 8.7-10.7)
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
2.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Results with reference substance (positive control):
- ErC50 72h: 1.05 mg/L
- Results with reference substance valid? Yes. The ErC50 72h values falls within the acceptable range of 0.92 mg/L and 1.46 mg/L (as defined by the standard NF EN ISO 8692-2012 )
Reported statistics and error estimates:
- CErx% 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

Validation criteria:

* Average growth rate for the control at 72 hours : 2.0 j-1 (> 0.92 j-1)

* Coefficient of variation of average specific growth rates during the whole test period in replicates control cultures : 0.29% (< 7%)

* The pH of the control medium did not increase by more than 1.5 units during the 72h period. (+0.4 pH units)

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the experimental conditions:
72h - ErC50 = 15.8 mg/L (15.2-16.4 mg/L)
72h - NOEC = 2.1 mg/L

Executive summary:

A study was performed to assess the acute toxicity of the test item on the growth of the green alga Pseudokirchneriella subcapitata.

The method followed was designed to be compatible with OECD Guidelines for Testing of Chemicals (2006) No. 201, "Frechwater Alga and Cyanobacteria, Growth Inhibilition Test", referenced as method C.3 of Council Regulation (EC) No. 761/2009

references as method C.4 -C of Council Regulation (EC) No. 440

The median effective concentrations (ErC50) 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: 2.1, 4.0, 7.7, 14.6, 27.7, and 52.6 mg/L.

 

The test item solutions were prepared by stirring an excess of test item in test medium using a propeller stirrer at approximately 1500 rpm for 24 hours. After the stirring period any undissolved test item was removed by filtration (0.2 µm Gelman Acrocap filter) to produce a 100% v/v saturated solution of the test item. This saturated solution was then further diluted as necessary, to provide the remaining test groups.

 

Each concentration and the controls were inoculated with approximately 10 000 cells per mL. The test was carried out over 72 hours at a temperature of 22°C+/- 2°C and constantly stirred (250 rev/min).

Each vessel concentration was tested 6 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 - ErC50 = 15.8 mg/L (15.2 -16.4 mg/L)

    * 72h - ErC20 = 11.6 mg/L (10.8 -12.4 mg/L)

    * 72h - ErC10 = 9.7 mg/L (8.7 -10.7 mg/L)

    * 72h NOEC = 2.1 mg/L