Reaction mass of 2-O-α-L-Rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid and α-L-Rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid

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:

14 - 18 March 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Organisation for Economic Cooperation and Development. OECD Guidelines for the Testing of Chemicals - Freshwater Alga and Cyanobacteria, Growth Inhibition Test, TG 201, adopted 23th March 2006, Annex 5 corrected 28th July 2011.

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

Commission Regulation (EC) No 761/2009 of 23 July 2009 amending, for the purpose of its adaptation to technical progress, Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), C.3. Freshwater Algae and Cyanobacteria, Growth Inhibition Test (O.J. L 220 of 24.8.2009).

Deviations:

no

GLP compliance:

no

Remarks:

, but the study was conducted in accordance with ISO/IEC 17025.

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 2-O-α-L-Rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid and α-L-Rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid

EC Number:

604-610-3

Cas Number:

147858-26-2

IUPAC Name:

Reaction mass of 2-O-α-L-Rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid and α-L-Rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION OF TEST SOLUTION
Since the test item is soluble, the test solution was prepared by dilution of a stock solution with algal medium (test item dissolved in Algal medium, Table 1). The pH of the test mixture was adjusted (pH 8.0 ± 0.2) and the test mixture was sterile filtered (0.45 μm aPES membrane Rapid- Flow, Thermo Scientific) into sterile test flasks. Finally, each flask (containing the resulting sterile test solution) was inoculated with an exponentially growing preculture of algae.
Pure algal medium served as blank controls.
For the incubation, the test flasks were then placed on an orbital shaker at a nominal shaking speed of about 130 revolutions per min.
The following test flasks were set up:
- Test solution (Tn); containing test medium, test item and algae (six replicate samples);
- Blank control (Bn); containing test medium and algae (six replicate samples).

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Test organism: Axenic slope culture of Desmodesmus subspicatus 86.81 SAG (Collection of Algal Cultures, Institute of Freshwater Ecology, University of Göttingen, Göttingen, Germany).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

none

Test conditions

Details on test conditions:

TEST SYSTEM
- Test vessels: 250 ml flasks, all-glass, with 100 ml of test medium, shaken (130 rpm)
- Test medium: Recommended OECD algal medium
- Preculture: Exponentially growing liquid culture of Desmodesmus subspicatus
- Illumination
a) Source: continuous from Osram Fluora L 18W77 and Osram Daywhite L 18W840 (Osram AG, Winterthur, Switzerland)
b) Light intensity: the light intensity amounts to about 3000 lux which corresponds to about 40 μE•m-2•s-2
c) Homogeneity: the light intensity is maintained within ±15% from the aver-age light intensity over the incubation area. The test vessels are repositioned every day within the incubation area to minimize variation
- Temperature: 21 to 24°C, maintained at ± 2°C in a thermo-controlled room
- pH: Initially adjusted to 8 ± 0.2; the pH of the control medium
should not increase by more than 1.5 units during the test
- Test type: Static exposure conditions over a period of 72 h
- Starting cell density 0.5–0.85 μg dry weight / ml corresponding to about 2–5•10^3 cells/ml (i.e. OD680 of about 0.005)

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

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

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Reported statistics and error estimates:

No statistical analysis was performed.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

- (72h) EC50: >100 mg/l  (nominal; based on growth rate);
- (72h) NOEC: 100 mg/l (nominal; based on growth rate).
The criteria for classification of a substance in category Acute 1 are defined on the basis of acute aquatic toxicity data only (EC50 or LC50); classification is required for values ≤ 1 mg/L. Therefore, the substance does not need to be classified for acute (short-term) aquatic hazard.
Further, classification as aquatic chronic category 3 or worse is required if the 96 hr LC 50 (for fish), and/or 48 hr EC 50 (for crustacea) and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) values are > 100 mg/l (and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the log Kow ≥ 4). The determined 72h EC50 is > 100 mg/l, so no classification as aquatic chronic Cat. 3 or worse is required.

Executive summary:

The median growth inhibiting concentration (ErC50/EyC50) and the no-observed-effect concentration (NOErC/NOEyC) based on the average specific growth rate and the yield (algal biomass production) of the test item 'Decanoic acid, 3-[[6-deoxy-2-O-(6-deoxy-α-L-mannopyranosyl)-α-L-mannopyranosyl]oxy]-, 1-(carboxymethyl)octyl ester, mixt. with 1-(carboxymethyl)octyl 3-[(6-deoxy-α-L-mannopyranosyl)oxy]decanoate' to the green alga Desmodesmus subspicatus were investigated in a screening test over a period of 72 h.

Since the test item is soluble, the test solution was prepared by dilution of a stock solution with algal medium. The only applied nominal concentration of the test material was 100 mg/l (limit test). Six parallel test vessels were used for the untreated controls and six for the test concentration. The evaluation of the test was based on the nominal concentration of the test item, assuming the test item to be stable in water over 72 h.

With respect to algal growth rate and to yield (algal biomass production), no significant effects were observed at the nominal concentration of 100 mg/l, as compared to the untreated controls. Based on these data, the nominal median effect concentration with respect to growth rate (ErC50/0-3 days) and to yield (EyC50/0-3 days) of the test item to Desmodesmus subspicatus were both estimated to be >100 mg/l nominal concentration.

The no-observed-effect concentrations with respect to growth rate (NOErC) and to yield (NOEyC) are both 100 mg/l nominal concentration.