oligomeric Reaction products from Hydrogenation and Hydrolysation of Starch

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:

Feb - Jun 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

473-690-8

EC Name:

-

Cas Number:

738602-93-2

Molecular formula:

not applicable for UVCB

IUPAC Name:

(2R,3R,4S,5S,6R)-2-{[(2R,3R,4R,5S,6R)-5-{[(2R,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-{[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}oxan-2-yl]oxy}-3,4-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}-6-(hydroxymethyl)oxane-3,4,5-triol; (2S,3R,5R)-4-{[(2R,3R,4R,5S,6R)-5-{[(2R,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-{[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}oxan-2-yl]oxy}-3,4-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}hexane-1,2,3,5,6-pentol

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: sponsor, Batch 4G08
- Purity, including information on contaminants, isomers, etc.: Mixture of maltotriosyl glucoside and othe roligoglucosaccharides (approx. 95 %)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature at about 20 °C, away from direct sunlight.
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage: assumed stable
- Stability in the medium, i.e. sensitivity of the test material to hydrolysis and/or photolysis: assumed stable
- Solubility and stability of the test material in the solvent/vehicle and the exposure medium: analytical determination of solubility/concentrations.
- Reactivity of the test material with the incubation material used (e.g. plastic ware): assumed stable

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

For the determination of the actual test item concentrations the following samples were taken:
Just before the start of the test: duplicate samples from the test medium, duplicate samples from the control
After 48 hours: duplicate samples from the test medium, duplicate from the control

Test solutions

Vehicle:

no

Details on test solutions:

The test medium was prepared by dissolving the test item completely in 300 mL of test water using intense stirring for 10 minutes at room temperature

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

The test organism used for the study was Scenedesmus subspicatus CHODAT, Strain No. 86.81 SAG, supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Göttingen, D-37073 Göttingen, Germany). The algae had been grown in RCC's laboratories under standardized conditions according to the test guidelines.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

no

Test conditions

Hardness:

0.24 mmol/L

Test temperature:

23 °C

pH:

7.9

Dissolved oxygen:

not measured

Salinity:

not applicable

Conductivity:

not applicable

Nominal and measured concentrations:

The analytically determined test item concentration in the analyzed test medium was 103% of the nominal value at the start of the test. This shows the correct preparation of the test medium (see analytical results and Table 2 in the attached analytical phase report). At test end, the test item concentration was 28% of nominal. Since the test item is known to be hydrolytically stable the decrease in
concentration is considered to be caused by photolytical degradation of the test item due to the strong irradiation in this algae test.

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml Erlenmeyer flasks
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass, 50 mL, 15 ml fill volume
- Aeration: not stated
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): not applicable
- Initial cells density: 10000 cells per mL
- Control end cells density: 1040000 cells per mL
- No. of organisms per vessel: not applicable
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): not applicable

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The algae were cultivated and tested in synthetic test water, prepared according to the test
guidelines.
- Total organic carbon: not determined
- Particulate matter: not determined
- Metals: not determined
- Pesticides: not determined
- Chlorine: not determined
- Alkalinity: not determined
- Ca/mg ratio: not determined
- Conductivity: not determined
- Culture medium different from test medium: no
- Intervals of water quality measurement: at start and at end

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: contineously
- Light intensity and quality: measured
light intensity of about 8200 Lux (mean value), range: 7600 to 8800 Lux (minimum and
maximum value of measurements at nine places distributed over the experimental area at the
surface of the test media).
- Salinity (for marine algae): not applicable

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter
- Chlorophyll measurement: no
- Other:

A single test item concentration of nominal 100 mg/L was tested.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

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

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:

biomass

Details on results:

The microscopic examination of the algal cells after 72 hours exposure showed no difference
between the algae growing in test medium containing the test item at the nominal
concentration of 100 mg/L and the algal cells in the control. There were no obvious effects on
the shape and size of the algal cells growing in the test medium at this nominal concentration.

Results with reference substance (positive control):

For evaluation of the algal quality and experimental conditions, potassium dichromate is tested
as a positive control at least once a year to demonstrate satisfactory conditions of the test. The
latest result of the positive control test showed that the toxic performance was valid and within
the historical range in the RCC laboratory.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

The influence of the test item MG-60 on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the EU Guideline C.3 and OECD Guideline No.201.
A limit test was performed in accordance with the EU Commission Directive 92/69/EEC to demonstrate that the test item has no toxic effect on Scenedesmus subspicatus up to and including a nominal concentration of 100 mg/L. Thus the only concentration tested was nominal 100 mg/L and a control.
The analytically determined test item concentration in the analyzed test medium was 103% of the nominal value at the start of the test. This shows the correct preparation of the test medium. At test end, the test item concentration was 28% of nominal. Since the test item is known to be hydrolytically stable, the decrease in concentration is considered to be caused by photoiyticai degradation of the test item due to the strong irradiation in this algae test.
The reported biological results are based on the nominal as well as on the mean measured concentration of the test item of 53 mg/L.
The mean algal cell densities in the test medium of nominal 100 mg/L (mean measured 53 mg/L) were nearly identical with or even slightly higher than those in the parallel control culture throughout the entire test duration. After 72 hours, the difference of the mean biomass and the mean growth rate compared to the control was 7.5 and 2.2%, respectively. This small difference (< EC10) was considered to be due to biological variation of algae growth rather than to be caused by a toxic effect of the test item.

Thus, the test item MG-60 and its degradation products clearly had no inhibitory effect on the growth of Scenedesmus subspicatus during the exposure period of 72 hours at a nominal test concentration of nominal 100 mg/L (mean measured 53 mg/L). This test concentration was therefore determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours). This value might even be higher, but concentrations in excess of nominal 100 mg/L have not been tested, according to EU Commission Directive 92/69/EEC.
The 72-hour LOEC (lowest concentration tested with toxic effects) and the 72-hour Ec10 and EC50 for the algal biomass b and growth rate r could not be quantified due to the absence of a toxic effect of MG-60 at the tested concentration. However, these parameters were clearly higher than nominal 100 mg/L (mean measured 53 mg/L).