Fatty acids C8-18 (even numbered), mono- and diesters with sucrose

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:

18 - 21 Dec 2017

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2011

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids C8-18 (even numbered), mono- and diesters with sucrose

EC Number:

947-862-2

Molecular formula:

not applicable, substance is UVCB

IUPAC Name:

Fatty acids C8-18 (even numbered), mono- and diesters with sucrose

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All test concentrations incl. control
- Sampling method: Samples were taken at the beginning and end of exposure period.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test sample (0.0800 g) was dissolved in medium (800 mL) to prepare the stock solution of 100 mg/L. Required volumes of the stock solution and medium were mixed and stirred in a preparation container to prepare the test solution which was divided into each test vessel. The 100 mg/L test solution was prepared by direct addition.
- Eluate: no
- Differential loading: no (except for 100 mg/L)
- Controls: yes, test medium control
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: ATCC 22662
- Source (laboratory, culture collection): supplied by American Type Culture Collection, USA

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

22.8 - 23.0 °C

pH:

7.7 - 8.0

Nominal and measured concentrations:

nominal: control, 1.00, 3.16, 10.0, 31.6, 100 mg/L
measured: < LOQ, 0.98, 2.69, 8.47, 27.9, 93.6 mg/L (geometric mean)

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterilized 300 mL Erlenmeyer flask (with gas-permeable Silicosen ®)
- Material, size, headspace, fill volume: glass, 300 mL, headspace: 200 mL, fill volume: 100 mL
- Aeration: constantly shaken on a rotary shakter (100 rpm)
- Initial cells density: 0.75E+04 cells/mL (equivalent to 56 Chlorophyll fluorescence units)
- Control end cells density: No cell density given (3900 Chlorophyll fluorescence units (mean))
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes (prepared in purified water)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: purified tap water
- Culture medium different from test medium: no
- Intervals of water quality measurement: Water quality parameters were measured regularly (temperature, pH.

OTHER TEST CONDITIONS
- Sterile conditions: yes
- Adjustment of pH: no
- Photoperiod: constant illumination
- Light intensity and quality: 90 µmol*m-2*s-1 (wavelength: 400 - 700 nm)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Chlorophyll measurement: Every 24 h the Chlorophyll content was measured using a spectrofluorometer to determine the Chlorophyll fluorescence value.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.16
- Range finding study
- Test concentrations: 1.00, 3.20, 10.0, 32.0, 100 mg/L
- Results used to determine the conditions for the definitive study: -2.1% inhibition at 1 mg/L, 5% inhibition at 3.20 mg/L, 13% inhibition at 10.0 mg/L, 17% inhibtion at 32 mg/L, 28% inhibition at 100 mg/L (inhibition values after 72 h).

Reference substance (positive control):

yes

Remarks:

Potassium dichromate was tested regularly (last test: 25 - 28 Dec 2017)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.16 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
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: All exposure levels were clear and colorless.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50 (72 h): 1.3 mg/L (95% CI: 0.61 - 1.4 mg/L)

Reported statistics and error estimates:

Bartlett's test, One-way ANOVA, Dunnett's multiple comparison test

Any other information on results incl. tables

The measured test concentrations were in the range of 80 - 120% of nominal (see Table 2). Thus, it is justified that the effect concentrations were based on the nominal concentrations.

Table 1: Growth rate and growth inhibition rate

Nominal concentration [mg/L]	Vessel No.	Growth rate (0-3 d)	Growth inhibition rate [%]
Control	A	1.41	-
	B	1.40	-
	C	1.38	-
	D	1.43	-
	E	1.42	-
	F	1.47	-
	Mean	1.42	-
	S.D.	0.0302	-
1.00	A	1.47	-4.0
	B	1.45	-2.0
	C	1.54	-8.6
	Mean	1.49	-4.9
	S.D.	0.0486	3.4
3.16	A	1.41	0.61
	B	1.40	0.97
	C	1.48	-4.1
	Mean	1.43	-0.85
	S.D.	0.0405	2.9
10.0	A	1.29	9.2
	B	1.23	13
	C	1.32	7.2
	Mean	1.28	9.9
	S.D.	0.0433	3.1
31.6	A	1.15	19
	B	1.13	21
	C	1.24	13
	Mean	1.17	17
	S.D.	0.0582	4.1
100	A	1.04	26
	B	1.00	29
	C	1.15	19
	Mean	1.07	25
	S.D.	0.0775	5.5

n.d.: < 0.541 mg/L

Table 2: Analytical results

Nominal concentration [mg/]	Measured concentration [mg/L] (%)
	0 h	72 h	Geometric mean
Control	Not detected	Not detected	-
1.00	0.980 (98.0)	0.980 (98.0)	0.980 (98.0)
3.16	2.85 (90.2)	2.53 (80.2)	2.69 (85.1)
10.0	8.95 (89.5)	8.01 (80.1)	8.47 (84.7)
31.6	29.6 (93.7)	26.2 (83.0)	27.9 (88.2)
100	101 (101)	87.2 (87.2)	93.6 (93.6)

Table 3: 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.	Factor of > 64	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%	11%	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%.	2.1%	yes

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

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