[No public or meaningful name is available]

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:

11 - 28 Nov 201

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2006; Annex 5 corrected 28 July 2011

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, 2000.

Principles of method if other than guideline:

A combined limit/range-finding test was performed.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids, vegetable-oil, polymd., esters with 1,2-hexadecanediol

Cas Number:

68910-99-6

Molecular formula:

Not applicable (i.e., UVCB substance)

IUPAC Name:

Fatty acids, vegetable-oil, polymd., esters with 1,2-hexadecanediol

Test material form:

other: paste

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test solution was prepared by adding the required amount of test material to the test medium. The solution was stirred for three days. Subsequently the solution was filtered (0.45 µm membrane filter, RC55, Whatman).
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): The test solution was clear and colorless at the end of the preparation procedure.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): In-house laboratory culture

ACCLIMATION
- Acclimation period: 3 days before the start of the test, cells from the algal stock culture were inoculated in culture medium at a cell density of 1 E+04 cells/mL. The pre-culture was maintained under the same conditions as used in the test. The cell density was measured immediately before use.
- Culturing media and conditions (same as test or not): Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 21-24°C.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

21 - 23°C

pH:

8.0 - 8.2

Nominal and measured concentrations:

WAF prepared at a loading rate of 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass vessels (100 mL, nominal volume)
- Fill volume: 50 mL
- Initial cells density: 10000 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, M2; according to the OECD 201 Guideline

OTHER TEST CONDITIONS
- Photoperiod: Continuous
- Light intensity and quality: TLD-lamps, 86 to 89 µE.m-2.s-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations: every 24 hours. At the beginning of the test, cells were counted using a microscope and a counting chamber. Thereafter, cell densities were determined by spectrophotometric measurement of samples at 680 nm using a spectrophotometer with immersion probe (pathlength =10 mm).

RANGE-FINDING STUDY
- Test concentrations: WAFs prepared at loading rates of 1.0 and 10 mg/L
- Results used to determine the conditions for the definitive study: no inhibition observed

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Results with reference substance (positive control):

Septermber 2017: The EC50 for growth rate inhibition (72h-ERC50) was 1.1 mg/L with a 95% confidence interval ranging from 1.1 to 1.1 mg/L.

Reported statistics and error estimates:

Statistical analysis of the data was not needed as the effects recorded showed a stimulation rather than an inhibition of growth.

Any other information on results incl. tables

Table 1: Growth Rate And Percentage Inhibition For The Total Test Period

WAFs prep. at nominal loading rate (mg/L)	Mean Growth rate	Std. Dev.	n	%Inhibition
Control	1.931	0.0177	6
100	1.940	0.0161	6	-0.5

Table 2: Validity criteria for OECD 201.

Criterion from the guideline	Outcome	Validity criterion fulfilled
The biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72-hour test period.	329	yes
The mean coefficient of variation for section-by-section specific growth rates (days 0-1, 1-2 and 2-3, for 72-hour tests) in the control cultures must not exceed 35%	21%	yes
The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 7% in tests with Pseudokirchneriella subcapitata and Desmodesmus subspicatus. For other less frequently tested species, the value should not exceed 10%.	0.9%	yes

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.