sucrose laurate

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 10-14, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test material form:

solid: granular

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Mitsubishi-Kagaku Foods Corporation; 6912911B
- Expiration date of the lot/batch: Sept. 11, 2018
- Purity test date: Oct. 14, 2016

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: below 15 degrees C, dark

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Dissolved in water

FORM AS APPLIED IN THE TEST (if different from that of starting material): Solution

Sampling and analysis

Analytical monitoring:

not required

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Stock solution was prepared at a concentration of 10 g/L in water. Test solutions of 10, 100, and 1000 mg/L were made.
- Controls: 3 blank controls, 3 bottles of reference substance (3,5-diclorophenol) per each concentration (1, 10, and 50 mg/L), and 3 abiotic controls
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Brianzacque SRL (Monza-Italia), San Rocco, Italy
- Preparation of inoculum for exposure: Activated sludge was collected on the day of use. Settling was not necessary.
- Pretreatment: Sludge was washed and analyzed, and continuously aerated prior to the test.
- Initial biomass concentration: 1.5 g/L

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Remarks on exposure duration:

Incubation period was 3 hrs, the dissolved oxygen levels were then monitored.

Test conditions

Test temperature:

20 +/- 2 degrees C

pH:

7.33 synthetic sewage feed
7.27 reference substance stock solution

Dissolved oxygen:

above 60% saturation

Salinity:

0.70 mg/L Sodium chloride
0.40 mg/L Calcium chloride
0.20 mg/L Magnesium sulphate heptahydrate
2.80 mg/L Anhydrous potassium monohydrogen phosphate

Nominal and measured concentrations:

Nominal:
10, 100, and 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: bottles
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: glass
- Aeration: yes
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per abiotic control (replicates): 3
- Sludge concentration (weight of dry solids per volume): 1.5 g/L
- Nutrients provided for bacteria: yes
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water
- Particulate matter: no
OTHER TEST CONDITIONS
- Details on termination of incubation: After incubation, samples were transferred to glass bottles with magnetic stirrers, and an oxygen probe was then inserted into the neck of the bottle.
EFFECT PARAMETERS MEASURED (with observation intervals if applicable): dissolved oxygen
TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10x
- Test concentrations: 10, 100, and 1000 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: Total respiration rate was inhibited 92.23% at 50 mg/L
- Other:

Any other information on results incl. tables

The % total respiration inhibition of the test item was:

5.86% at 10 mg/L

7.27% at 100 mg/L

19.49% at 1000 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50 for microorganisms is > 100 mg/L.

Executive summary:

The toxicity of LMD to microorganisms was tested in an OECD Guideline 209 study. Activated sludge was exposed to concentrations of 10, 100, and 1000 mg/L for 3 hrs, and then the oxygen uptake was measured. Due to variability, the EC50 was reported as an order of magnitude as according to the guidelines. The EC50 for microorganisms is > 100 mg/L.