Whey, lactose-low

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 306 (Biodegradability in Seawater)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Whey, lactose-low

EC Number:

295-893-9

EC Name:

Whey, lactose-low

Cas Number:

92129-93-6

IUPAC Name:

Whey, lactose-low

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

other: seawater inoculum

Details on inoculum:

The seawater is collected from an expected non-polluted location in Norway. It is stored for 2-5 days after tapping on 10-L tanks at 20+/- 2°C in the dark for ageing of the water to obtain degradation of inherent organic materials. The aged seawater is aerated for 20-30 minutes (sterile air is blown through the tanks) and fortified with nutrient solutions enhancing bacterial growth. Concentration of viable aerobic heterotrophic bacteria in aged seawater is determined by plate count method.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Solutions of blanks, reference and test substances were incubated at 20.8-21.6°C. The water temperature measured varied within the range 19.1-19.3°C.
Light conditions: darkness
Dissolved oxygen after 28 days were 5.19 mg oxygen/L for the test substance and 3.19 mg oxygen/L for the reference substance.

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 72.81

Sampling time:

28 d

Details on results:

Percentage biodegradability was determined as BOD of amount organic material related to the COD of amount organic material in the complete test substance.
Lag time: 0-2 days
Time required for 50% of total biodegradation: 2-4 days

Any other information on results incl. tables

Test acceptability:

- Oxygen consumption in the blanks during the test period was less than 30% and within limits for test acceptability.

- The test was performed within accepted ranges for temperature (20 +/- 2°C) during the test period of 28 days.

- Percentage BOD of the reference substance relative to its reference value (ThOD or COD) reached a level > 60% (72.90%) during the test period and was within limits for test acceptability.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The biodegradability of the test substance was 72.8% of its COD value at a test concentration of 2 mg organic material/L seawater, indicating that the test substance is well biodegradable in non-polluted seawater.