Fatty acids C18-C22 (even numbered), tetraesters with pentaerythritol

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:

30 Mar - 27 Apr 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Kurume central sewage treatment center (Kurume, Fukuoka, Japan)
- Preparation of inoculum for exposure: After collection, the activated sludge was aerated at about 22°C until use for the test (aeration time: 3.5 hours).
- Concentration of sludge: 30 mg/L

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 22.0°C
- pH: 7.4
- pH adjusted: yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: glass vessel
- Number of culture flasks/concentration: 2
- Test performed in closed vessels due to significant volatility of test substance:
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: soda lime for absorption of carbon dioxide

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Other: one procedure control

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

3

Sampling time:

28 d

Table 1: Validity criteria

	Value in present test	Value of criterion
Difference between extremes of replicate values of percentage biodegradation of the test item by BOD on 28 days	4%	< 20%
Percentage biodegradation of sodium benzoate by BOD on 14 days	87%	≥ 60%
Percentage biodegradation of test item and sodium benzoate by BOD on 14 days	58%	≥ 25%
BOD of control blank on 28 days	17 mg/L^*1 17 mg/L^*2	≤ 18 mg (≤ 60 mg/L)

*1 Measurement value of BOD (Vessel No. 5): (5.0 mg)I[test volume (300 mL)I1000] = 17 mg/L

*2 Measurement value of BOD (Vessel No. 6): (5.1 mg)I[test volume (300 mL)I1000] = 17 mg/L

Table 2: Calculation table for percentage biodegradation by BOD

Duration of incubation. 28 days
Vessel no.	7^th day		14^thday		21^stday		28^thday		Average
	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	Deg. (%)
[1]	3.5	0	4.0	-2	4.8	-1	5.3	1	3
[2]	4.6	5	5.6	4	6.0	4	6.3	5
[4]	42.8	52	48.5	58	50.2	59	50.7	60	-
[5]	3.9	-	4.7	-	5.0	-	5.0	-	-
[6]	2.8	-	4.3	-	5.1	-	5.1	-	-
[3]	43.2	80	47.9	87	49.7	89	50.3	90	-

Deg. : Percentage biodegradation

Sludge +test item :Vessel No. [1][2]

*5 Sludge+ test item2 :Vessel No. [4]

Control blank :Vessel No. [5][6]

Sludge+ SB *6 :Vessel No. [3]

*5 test item2: Test item+ sodium benzoate

*6 SB: Sodium benzoate

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Description of key information

Not readily biodegradable: 3 % after 28 days (O2 consumption, OECD 301 F)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The biodegradation of fatty acids C18-C22 (even numbered), tetraesters with pentaerythritol was tested in a GLP guideline study following OECD 301 F. The study was conducted under aerobic conditions using domestic activated sludge as inoculum. During the incubation time of 28 days the degradation was followed by determining the O2 consumption. A degradation rate of 3 % was determined after 28 days. Therefore, the substance is considered to be not ready biodegradable according to OECD criteria.