Polar modified Rice Bran Wax

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05.2019 - 08-2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

ISO/DIS 17556.2 (Plastics - Determination of the Ultimate Aerobic Biodegradability in Soil by Measuring the Oxygen Demand in a Respirometer or the Amount of Carbon Dioxide Evolved)

Version / remarks:

2019

GLP compliance:

yes

Test type:

laboratory

Test material

Test material information

Constituent 1

Test material form:

solid: flakes

Details on test material:

Batch number: K45989631508
Colour: white
Storage conditions: room temperature in the dark

Radiolabelling:

no

Study design

Oxygen conditions:

aerobic

Soil classification:

other: The standard soil inoculum consists of a mixture of 70% industrial quartz sand, 10% kaolinite clay, 16% natural soil and 4% mature compost (percentages expressed on dry weight basis).

Year:

2018

Soil properties

Soil type:

other: mixture of quartz sand, kaolinite clay, natural soil and mature compost

% Clay:

10

% Sand:

70

Details on soil characteristics:

The standard soil inoculum consists of a mixture of 70% industrial quartz sand, 10% kaolinite
clay, 16% natural soil and 4% mature compost (percentages expressed on dry weight basis).
Before use the natural soil is sieved on a screen of 2 mm, while the mature compost is sieved
on a screen of 5 mm. The fine fractions are used for the inoculum. Finally, salts are added to
the standard soil mixture by means of nutrients solution. The composition of the nutrients
solution is given in Table 1. It is recommended that the soil inoculum has a water content
between 40% and 60% of the total water holding capacity and a pH between 6.0 and 8.0.
Table 1. Nutrients solution
Chemical Amount (g/l)
KH2PO4 9.6
MgSO4 4.8
NaNO3 19.2
Urea 9.6
NH4Cl 19.2
Table 3. Characteristics of the inoculum
Characteristics Inoculum
Total solids (TS, %) 87.7
Moisture content (%) 12.3
Volatile solids (VS, % on TS) 3.4
Ash content (% on TS) 96.6
pH 7.6
Electrical conductivity (EC, µS/cm) 1282
Total water holding capacity (WHCtot, % on TS) 29.7
Total N (g/kg TS) 3.0
C/N 6
The total solids (TS), volatile solids (VS), total organic carbon content (TOC) and theoretical
amount of evolved carbon dioxide (ThCO2) of the reference and test item are summarised in
Table 4.
Table 4. TS, VS, TOC and ThCO2 of reference and test item
Test item TS (%) VS (% on TS) TOC (%) ThCO2 (mg/g)
Cellulose 97.0 100.0 42.7 1564
LICOCARE RBW 102 FL TP 98.0 99.9 75.4 276

Duration of test (contact time)

Soil No.:

#1

Duration:

390 d

Initial test substance concentration

Soil No.:

#1

Initial conc.:

4 mg/kg soil d.w.

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on experimental conditions:

The standard soil inoculum consists of a mixture of 70% industrial quartz sand, 10% kaolinite
clay, 16% natural soil and 4% mature compost (percentages expressed on dry weight basis).
Before use the natural soil is sieved on a screen of 2 mm, while the mature compost is sieved
on a screen of 5 mm. The fine fractions are used for the inoculum. Finally, salts are added to
the standard soil mixture by means of nutrients solution. The composition of the nutrients
solution is given in Table 1. It is recommended that the soil inoculum has a water content
between 40% and 60% of the total water holding capacity and a pH between 6.0 and 8.0.
Table 1. Nutrients solution
Chemical Amount (g/l)
KH2PO4 9.6
MgSO4 4.8
NaNO3 19.2
Urea 9.6
NH4Cl 19.2
A defined amount of test and reference item is mixed with the inoculum (typically 1 g to 6.25 g
of material with 500 g soil) and introduced into the reactors. The reactor also contains a beaker
with KOH to absorb the carbon dioxide, released during the incubation and a beaker with water
to prevent drying out of the soil. The reactors are closed airtight and placed in the dark at 25°C
± 2°C (see Figure 1). Also a technical control is taken along. These empty reactors only contain
a beaker of water and a beaker of KOH and are used to correct for the CO2 in the air in the
headspace of the vessel.
The CO2 production is determined by titration. The percentage of biodegradation is calculated
as the percentage of solid carbon of the test item that has been converted to gaseous, mineral
C under the form of CO2. After each titration, a new beaker with KOH is put into the reactor.
At the same time the soil is stirred and moistened if needed.

Results and discussion

% Degradation

Parent/product:

product

Key result

Soil No.:

#1

% Degr.:

90.5

Parameter:

CO2 evolution

Sampling time:

390 d

Transformation products:

not measured

Volatile metabolites:

no

Details on results:

The results on the calculation of the biodegradation percentages at the end of the test (390
days) are summarized in Table 6. The percentages are determined by the ratio of gaseous
carbon, which is found back under the form of carbon dioxide, to the original amount of carbon
input. Figure 5 shows the evolution of the average biodegradation percentages of reference
and test item, while Figures 6 and 7 represent the biodegradation of the separate replicates.
Table 6. Biodegradation percentages at the end of the test (390 days)
Test series
Average
Cinput
(mg)
Average
Cgaseous
(mg)
Biodegradation
(%) 95% CL
AVG SD REL
Cellulose 853 735 86.2 2.7 100.0 6.3
LICOCARE
RBW 102 FL TP 1507 1176 78.1 2.9 90.5 5.4
With AVG = average, SD = standard deviation, REL = relative biodegradation and CL = confidence limits
The biodegradation of reference item cellulose started after a lag phase of approximately 3
days and proceeded at a good rate. After 27 days cellulose was already degraded by 70.7%.
From then on the biodegradation rate gradually slowed down and at the end of the test (390
days) a plateau in biodegradation was reached at a level of 86.2% ± 2.7%. The test is
considered valid when the degree of biodegradation of the reference material cellulose is more
than 60% at the plateau phase or at the end of the test. This requirement was clearly fulfilled.
Test item LICOCARE RBW 102 FL TP started to degrade slowly, but the biodegradation rate
gradually increased to a moderate rate. After 180 days the test item was degraded by 54.4%
and at the end of the test (390 days) an absolute biodegradation of 78.1% ± 2.9% was
measured. On a relative basis, compared to suitable reference substrate cellulose, a
biodegradation percentage of 90.5% was calculated.
The OK biodegradable SOIL conformity mark of TÜV AUSTRIA Belgium and the DIN-Geprüft
biodegradable in soil conformity mark of DIN CERTCO stipulate a biodegradation of at least
90% in total or 90% of the maximum degradation of a suitable reference item after a plateau
has been reached for both reference and test item. The 90% limit must be reached within 2
years and the test should be executed at ambient temperature. From these results it can be
concluded that test item LICOCARE RBW 102 FL TP fulfilled the 90% biodegradability
requirement within 390 days of testing under the given aerobic conditions.

Results with reference substance:

The biodegradation of reference item cellulose started after a lag phase of approximately 3
days and proceeded at a good rate. After 27 days cellulose was already degraded by 70.7%.
From then on the biodegradation rate gradually slowed down and at the end of the test (390
days) a plateau in biodegradation was reached at a level of 86.2% ± 2.7%. The test is
considered valid when the degree of biodegradation of the reference material cellulose is more
than 60% at the plateau phase or at the end of the test. This requirement was clearly fulfilled.

Applicant's summary and conclusion

Conclusions:

It can be concluded that test item LICOCARE RBW 102 FL TP fulfilled the 90% biodegradability
requirement within 390 days of testing under the given aerobic conditions.

Executive summary:

The aerobic biodegradation of LICOCARE RBW 102 FL TP was evaluated in a standard soil
biodegradation test according to ISO 17556 (2019). The incubation temperature was
continuously kept at 25°C ± 2°C. The total test duration was 390 days.

According to ISO 17556 (2019) the test is considered valid when the standard deviation of the
CO2 production of the control reactors is less than 20% of the mean at the plateau phase or at
the end of the test. After 390 days a value of 7.4% was reached, demonstrating the good precision
of the test. Furthermore the degree of biodegradation of the reference material (cellulose) should
be more than 60% at the plateau phase or at the end of the test. After 390 days a biodegradation
percentage of 86.2% ± 2.7% was measured. Both requirements were clearly fulfilled.

The biodegradation of test item LICOCARE RBW 102 FL TP proceeded well throughout the
test. After 180 days the test item was degraded by 54.4% and at the end of the test (390 days)
an absolute biodegradation of 78.1% ± 2.9% was reached. On a relative basis, compared to
suitable reference substrate cellulose, a biodegradation percentage of 90.5% was calculated.

The OK biodegradable SOIL conformity mark of TÜV AUSTRIA Belgium and the DIN-Geprüft
biodegradable in soil conformity mark of DIN CERTCO stipulate a biodegradation of at least
90% in total or 90% of the maximum degradation of a suitable reference item after a plateau
has been reached for both reference and test item. The 90% limit must be reached within 2
years and the test should be executed at ambient temperature. From these results it can be
concluded that test item LICOCARE RBW 102 FL TP fulfilled the 90% biodegradability
requirement within 390 days of testing under the given aerobic conditions.

The results, obtained in this test, are valid for solid aerobic conditions only and cannot be
directly used for aqueous or for anaerobic conditions. Other tests are more suited to simulate
and examine the degradation under these circumstances.