Reaction products of behenic acid, Eicosadioic acid and Polyglyceryl-10

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26 July 2004 - 01 September 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

GLP compliance:

yes

Specific details on test material used for the study:

Identity: Nomcort HK-P
Batch no.: 2-10-A
Expiration date: April 29, 2007
Purity: 100%
Solubility in water: Insoluble
Aggregate state/physical form
at room temperature: Waxy solid I pellet form
Color: White to pale yellow
Melting point: About 68 °C
Storage conditions: Store in a dry, ventilated location. Keep away from
high temperature and sunlight, store in a closed container.
At RCC: At room temperature at about 20 °C, away
from direct sunlight

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

The study was performed with aerobic activated sludge from a wastewater treatment plant
(ARA Ergolz II, Fullinsdorf, Switzerland) treating predominantly domestic wastewater. The
sludge was washed twice with tap water by centrifugation and the supernatant liquid phase
was decanted. A homogenized aliquot of the final sludge suspension was weighed,
thereafter dried and the ratio of wet to dry weight was calculated.
Based on this ratio, calculated amounts of wet sludge were suspended in test water (see
2.4.1) to obtain a concentration equivalent to 4 g (±10%) dry material per liter. During
holding, the sludge was aerated at room temperature until use. Prior to use, the sludge was
diluted with test water to a concentration of 1 g per liter (dry weight basis). This diluted
activated sludge was used as inoculum to give a final concentration of 30 mg dry material per
liter.

Duration of test (contact time):

35 d

Initial conc.:

100 mg/L

Based on:

test mat.

Remarks:

WAV

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Apparatus: The test flasks (500-ml Erlenmeyer flasks, labeled with all necessary
information to ensure unmistakable identification) were incubated under
continuous stirring in a SAPROMAT 012 (Voitll GmbH, Heidenheim,
Germany). Oxygen consumption was recorded manually by taking a
daily reading at least on each working day.
Principle: Electro-chemical analysis process:
The biodegradation process consumes the dissolved oxygen in the liquid
and generates CO2. The CO2 is adsorbed by soda lime and the total
pressure decreases in the airtight test flasks. The pressure drop is
detected and converted into an electrical signal by means of an
electrode type manometer. The consumed oxygen is replaced by
electrolytically generated oxygen from a copper sulfate solution.
Test duration: 35 days. In accordance with the testing guidelines, the test was
prolonged beyond 28 days since the biodegradation curve of the test
item showed that biodegradation had started but the plateau had not
been reached within 28 days.
Light conditions: Darkness
Test temperature: 22 °C, maintained with a built-in thermostat and checked once per week.
pH: Prior to test start, the pH was measured in each test flask before the
addition of the activated sludge inoculum (Table 3). At the end of
incubation, the pH was measured again in each test flask.

Reference substance:

other: Sodium benzoate

Preliminary study:

not performed

Test performance:

In accordance with the testing guideline, the test was prolonged beyond 28 days, since the
biodegradation curve of the test item showed that biodegradation had started, but the plateau
had not been reached within 28 days.

Key result

Parameter:

% degradation (O2 consumption)

Value:

46

Sampling time:

28 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

53

Sampling time:

35 d

Details on results:

Points of degradation plot (test substance):
1 % degradation after 1 d
1 % degradation after 3 d
3 % degradation after 7 d
22 % degradation after 14 d
33 % degradation after 20 d
46 % degradation after 28 d

Parameter:

COD

Value:

2.16 mg O2/g test mat.

Results with reference substance:

Points of degradation plot (reference substance):
5 % degradation after 1 d
70 % degradation after 3 d
81 % degradation after 7 d
88 % degradation after 14 d
91 % degradation after 20 d
93 % degradation after 28 d

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

At the end of the exposure
period, the mean biodegradation of Nomcort HK-P amounted to 53%. Consequently,
Nomcort HK-P was found to be biodegradable under the test conditions within 35 days.
However, the pass level for ready biodegradability, i.e. biodegradation of at least 60% of the
COD in a 10-day window within the 35-day period of the test, was not reached.

Executive summary:

The test item Nomcort HK-P was investigated for its ready biodegradability in a manometric

respirometry test over 35 days based on EU Commission Directive 92l69 EEC, C.4-D (1992)

and OECD Guideline for Testing of Chemicals No. 301 F (1992).

In accordance with the testing guidelines, the test was prolonged beyond 28 days, since the

biodegradation curve of the test item showed that biodegradation had started, but the plateau

had not been reached within 28 days.

The percent biodegradation of the test item was calculated based on the chemical oxygen

demand {COD) of 2.16 mg 02'mg test item.

The biochemical oxygen demand (BOD) of Nomcort HK-P in the test media significantly

increased from about Day 8 until test termination after 35 days. At the end of the exposure

period, the mean biodegradation of Nomcort HK-P amounted to 53%. Consequently,

Nomcort HK-P was found to be biodegradable under the test conditions within 35 days.

However, the pass level for ready biodegradability, i.e. biodegradation of at least 60% of the

COD in a 10-day window within the 28-day period of the test, was not reached.

No degradation of the test item occurred in the abiotic control under the test conditions.

In the toxicity control, containing both Nomcort HK-P and the reference item sodium

benzoate, no inhibitory effect on the biodegradation of the reference item was determined.

Thus, Nomcort HK-P had no inhibitory effect on the activity of activated sludge

microorganisms.

In the procedure controls, the reference item sodium benzoate was degraded by an average

of 88% on exposure Day 14, and reached an average biodegradation of 94% by the end of

the test (Day 35), thus confirming suitability of the activated sludge.

Description of key information

a Guideline study on ready biodegradability available

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater