Apple, Malus sylvestris, ext.

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:

September, November 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Apple, Malus sylvestris, ext.

EC Number:

286-475-7

EC Name:

Apple, Malus sylvestris, ext.

Cas Number:

85251-63-4

IUPAC Name:

Apple, Malus sylvestris, ext.

Test material form:

solid: particulate/powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: The inoculum was a fresh sample of activated sludge and was collected from the aeration tank of a sewage treatment plant receiving predominantly domestic sewage.
- Sample site: Water treatment plant "STEP de Lille", 33290 Blanquefort (France) - Tank 1
- Laboratory culture: A filtration through a fine sieve (about 1 mm) was performed in order to remove coarse particles. After removal of any coarse particles, the sludge was washed by recantation in a mineral medium until sludge was considered free from excess substrate or inhibitor.
- Inoculum preconditioning: Pre-conditioning consisted in aerating sludge (in mineral medium) for 5-7 days before the test and at the test temperature.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 100 g/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST ITEM PREPARATION
The test item is soluble in water; it was diluted with mineral medium at 1g/L and directly introduced with sludge into each test vessels.
The test item was tested at 100 mg/L in mineral medium.
The test medium was the mineral medium, a weakly saline aqueous medium.

TEST CONDITIONS
Composition of medium: Mineral medium according to OECD 301F guideline
- Test temperature: The test was performed in darkness between 21.7 to 21.8°C (constant temperature +/- 1°C).
- Mineral medium - pH: 7.6
- Inoculum : pH: 6.7, Dissolved oxygen: 9.2 mg/L, Suspended solids concentration: 3.51 g/L
- Continuous darkness: Yes

TEST SYSTEM
- Culturing apparatus:WTW Oxitop (FCBA reference: ACQU 1011)
- Number of culture flasks/concentration: 3 flasks (test item and inoculum)
- Test performed in closed vessels: Yes
- A measured volume of inoculated medium containing a known concentration of the test item (100 mg/L) as the nominal sole source of Carbon, was stirred in a closed vessel at a constant temperature up to 28 days.
- Details of trap for CO2: Microbial respiration consumes O2 and releases CO2 which were absorbed by soda lime pellets present in the headspace of flasks. This produced a decrease in pressure in the flask proportional to the amount of oxygen taken up by the microbial population during biodegradation, which was expressed as a percentage of ThOD (Theoretical Oxygen Demand).
- Allowance was made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without the test item. Furthermore, in order to check the procedure, a reference item control (sodium benzoate 60.2 mg/L + inoculum) and toxicity control (sodium benzoate + inoculum +test item) were run in parallel.

SAMPLING
- Sampling frequency: 0 to 28 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 flasks (inoculum only)
- Reference item: 2 flasks (Sodium benzoate and inoculum)
- Toxicity control: 2 flasks (test item, sodium benzoate and inoculum)

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Preliminary study:

none

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

following the ThOD-NH4

Value:

ca. 104.31

St. dev.:

3.68

Sampling time:

28 d

% Degradation 2

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

following the ThOD-N03

Value:

ca. 98.61

St. dev.:

3.48

Sampling time:

28 d

Details on results:

The test item contains nitrogen according to the elementary analysis, the evaluation of biodegradation has to be based in the following expressed as ThODNH4 and ThODNO3.

The degradation for the 10-day window beginning was reached on Day 2, before the end of the 10-day window on Day 6 the mean degradation was 64.99% following the ThODNH4, therefore the D-day window was reached.
The degradation rate of the test item reached 100% (102.18 to 108.56) , following the ThODNH4, after 28 days of incubation.

The degradation for the 10-day window beginning was reached on Day 2, before the end of the 10-day window on Day 6 the mean degradation was 61.45% following the ThODNO3, therefore the D-day window was reached.
The degradation rate of the test item reached 98.61% (96.60 to 102.63%), following the ThODNO3, after 28 days of incubation.

BOD5 / COD results

Results with reference substance:

The reference item “Sodium benzoate” was degraded up to 91.39% and 92.78%( mean value: 92.09%) after 14 days.
Therefore, it confirms the suitability of the used aerobic sludge inoculum.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

All the validity criteria for OECD 301F were successful.
According to the OECD guideline 301F, the test item is considered to be readily biodegradable whatever the ThODNH4 and the ThODNO3

Executive summary:

The test item contains nitrogen according to the elementary analysis, the evaluation of biodegradation has to be based in the following expressed as ThODNH4 and ThODNO3.

The degradation for the 10-day window beginning was reached on Day 2, before the end of the 10-day window on Day 6 the mean degradation was 64.99% following the ThODNH4, therefore the D-day window was reached.

The degradation rate of the test item reached 100% (102.18 to 108.56) , following the ThODNH4, after 28 days of incubation.

The degradation for the 10-day window beginning was reached on Day 2, before the end of the 10-day window on Day 6 the mean degradation was 61.45% following the ThODNO3, therefore the D-day window was reached.

The degradation rate of the test item reached 98.61% (96.60 to 102.63%), following the ThODNO3, after 28 days of incubation.

The reference item “Sodium benzoate” was degraded up to 91.39% and 92.78%( mean value: 92.09%) after 14 days.Therefore, it confirms the suitability of the used aerobic sludge inoculum

  All the validity criteria for OECD 301F were successful.

 

According to the OECD guideline 301F, the test item is considered to be readily biodegradable whatever the ThOD_NH4and the ThOD_NO3.