D-glucitol monolaurate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 Aug - 15 Sep 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sorbitan, octanoate (2:3)

EC Number:

295-118-4

EC Name:

Sorbitan, octanoate (2:3)

Cas Number:

91844-53-0

IUPAC Name:

91844-53-0

Details on test material:

- Name of test material (as cited in study report): sorbitansesquioctanoate
- Physical state: liquid
- Analytical purity: 99%
- Lot/batch No.: ES 65631498
- Durability: 36 months
- Storage condition of test material: 20 °C

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

- Source of inoculum/activated sludge: Fresh samples from a lake, the effluent of a municipal sewage treatment plant and an extract of surface soil were mixed and cultivated in a laboratory sewage treatment. By aeration air germs were added. The sludge was used as inoculum until after at least one month's operation, but not after more than four months. Thereafter samples from the above mentioned sites were collected again, mixed with an aliquot of the old sludge and cultivated as described.
- Laboratory sewage treatment: Effluents were clear, temperature was kept between 20 and 25 °C, sludge settled well and aeration kept the mixture aerobic at all times
- Preparation of inoculum for exposure: A fresh sample from the Laboratory model activated sludge plant containing approximately 1.875 g suspended solids was collected and filtered by means of a water jet pump through a filter paper (Schleicher & Schüll, black ribbon 589(1)). The sludge was washed twice with mineral medium. Afterwards, it was suspended in 250 mL mineral medium an stirred until it was homogeneous. 4 mL of this solution were used to inoculate 1 litre of mineral medium.
- Concentration of sludge: 30 mg/L suspended solids

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 22 ± 1 °C
- pH: 7.47 - 7.59
- Suspended solids concentration: 30 mg/L

TEST SYSTEM
- Culturing apparatus: incubation device Sensomat system (Digital Respirometer System, Liebherr, Aqualytic, Langen, Germany)
- Number of culture flasks/concentration: 3
- Measuring equipment: The produced CO2 was trapped in potassium hydroxide. The pressure decrease was detected by the Sensomat.

SAMPLING
Oxygen consumption was measured 360 times and automatically recorded by the Sensomat.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 3 replicates
- Abiotic sterile control: yes, 2 replicates
- Toxicity control: yes, 2 replicates
- Reference substance: yes, 2 replicates

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

89

St. dev.:

1

Sampling time:

28 d

Details on results:

- 72% degradation occurred within the 10-day window. Therefore, the test substance can be regarded as readily biodegradable.
- The test substance is not assumed to be inhibitory, because 72% degradation (based on total ThOD or COD, respectively) occurred within 14 days in the toxicity controls.
- The degradation of the abiotic sterile controls was 5% after 28d. The result of the second vessel was considered to be an outlier and was therefore not taken into account.
- The mean oxygen uptake of the 3 inoculum blank controls was 57.7 mg/L after 28 d.

BOD5 / COD results

Results with reference substance:

- The reference substance sodium benzoate was biodegraded to an average of 93% within 14 days

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable