Registration Dossier

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:
Experimental dates: 13 April 2018 to 07 June 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Supplied by sponsor, batch ref 171116
- Expiration date of the lot/batch: 16 November 2019
- Purity test date: 16 November 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature, protect from light
- Stability under test conditions: No data


Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 1.0, 10 and 100% of a saturated solution prepared at 100 mg/L
- Sampling method: 2.0 mL taken from approximately centre of test vessels, replicates pooled at the end of exposure period prior to sampling for analysis
- Sample storage conditions before analysis: Samples were stored frozen (<15oC) until analysis

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Nominal 100 mg/L test item in test media was stirred for 3 days (in the dark). The resultant solution was filtered through 0.45 um membrane filter. Lower test concns prepared using nominal 100 mg/L stock solution.
- Eluate: M2 media
- Differential loading: No
- Controls: Test media only
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc.):PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances) : All test solutions clear and colourless at end of preparation procedure

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Green alga
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): In-house laboratory culture
- Age of inoculum (at test initiation): 3 days

ACCLIMATION
- Acclimation period: None
- Culturing media and conditions (same as test or not): Pre-culture medium OECD M2, also used for test

Study design

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

Test conditions

Hardness:
No data
Test temperature:
22 - 23oC
pH:
0h: 8.0 - 8.2
72h: 8.3 - 8.5
Dissolved oxygen:
No data
Salinity:
No data
Conductivity:
No data
Nominal and measured concentrations:
Nominal concn: control, 1.0, 10 and 100 % saturated solution prepared at 100 mg/L
Meansured concn: Time Weighted Average 0.037 mg/L at 100% SS
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open / closed
- Material, size, headspace, fill volume:
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate):
- Initial cells density:
- Control end cells density:
- No. of organisms per vessel:
- No. of vessels per concentration (replicates):
- No. of vessels per control (replicates):
- No. of vessels per vehicle control (replicates):

GROWTH MEDIUM
- Standard medium used: yes/no
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH:
- Photoperiod:
- Light intensity and quality:
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement:
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.037 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
< 0.037 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Statistical significance
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.037 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Biological relevance

Any other information on results incl. tables

Effect parameters

Results based on time-weighted average measured concentrations (mg/L)

NOEC

(statistical significance)

NOEC

(biological relevance)

EC50

Growth rate

0.037

0.037

>0.037

Yield

0.037

0.037

>0.037

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 72-hour EC50 and NOEC for growth rate inhibition for the green alga Raphidocelis subcapitata, also known as Pseudokirchneriella subcapitata was >0.037 mg/l and 0.037 mg/l (or equivalent to the nominal loading rate of >100 mg/l) based on the time weighted mean concentrations. These values were not biologically relevant. That is, the percentage growth inhibition was <10% in the test. The substance is not toxic to algae at its limit of solubility.
Executive summary:

A 72-hour toxicity study with the green alga, Raphidocelis subcapitata, also known as Pseudokirchneriella subcapitata, was conducted in accordance with the OECD test guideline 201 and in compliance with GLP. The test was performed at nominal loading concentrations of 1.0, 10, and 100% saturated solutions prepared by dilution from a 100 mg/l saturated solution. The time-weighted measured concentration at the highest tested concentration was 0.037 mg/l. Under the conditions of the test the EC50 for growth rate inhibition was >0.037 mg/l (or equivalent to the nominal loading rate of >100 mg/l) and NOEC of 0.037 mg/l. These values were not biologically relevant, that is, the percentage growth inhibition was <10% in the test (measured at 2%). The substance is not toxic to algae at its limit of solubility. This toxicity study is considered reliable and satisfies the guideline requirement for toxicity to aquatic algae.