Carboxylic acids, di-, C4-6

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: sewage treatment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

A read-across approach is taken from adipic acid, which is a structural analogue and serves as a good representation for the carboxylic acid mixture.

Reason / purpose for cross-reference:

read-across: supporting information

Principles of method if other than guideline:

Aerobic Sewage Treatment Simulation Test (Coupled-Units-Test ), comparable to OECD TG 303 A (Simulation Test-Aerobic Sewage Treatment. A: Activated Sludge Units)

GLP compliance:

no

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material:
PHYSICO-CHEMICAL PROPERTIES
- Melting point: 151°C (Rhodia Study, 2008)
- Boiling point: 337.5°C at 1013 hPa (Merck Index)
- Vapour pressure: 0.097 hPa at 18.5°C (Kirk-Othmer)
- Henry's law constant (for volatie substances): 9,656e-9 hPa m³/mol 25°C (Currenta, 2009)
- Water solubility: 23 g/L at 25°C (MITI, 1992)
- Solubility in organic solvents: Adipic acid is not stable in alcohol. The corresponding ester is formed (Beyer, 2004).
- log Pow: 0.093 at pH 3.3 (BASF-Study, 1988)
- pKa: 4.34-5.44 at 18°C; 4.43-5.42 at 20°C; 4.43 at 25°C (Beilstein, 2003)
- Base or acid catalysis of test material:
- UV absorption: t1/2 = 2,9d (Currenta, 2009)

OTHER PROPERTIES
- Adsorption characteristics: adsorption coefficient (Koc) 21.5 (Currenta, 2009)
- Toxicity to microorganisms: Activated sludge, 3-hour EC50 4747 mg/l (Bayer AG, 1988)

Radiolabelling:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

24 h

Based on:

DOC

% Degr.:

99

Parameter:

DOC removal

Sampling time:

1 d

Transformation products:

no

Initial concentration not reported

Conclusions:

In a waste water treatment simulation test a DOC removal of 99 % in 1 day was achieved. 

Executive summary:

In a waste water treatment simulation test (OECD TG 303 A "Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units) a DOC removal of 99 % in 1 day was achieved. 

Reference 2

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Basic data given

Justification for type of information:

A read-across approach is taken from adipic acid, which is a structural analogue and serves as a good representation for the carboxylic acid mixture.

Qualifier:

according to guideline

Guideline:

other: OECD TG 302 B "Inherent biodegradability"

Principles of method if other than guideline:

modified Zahn-Wellens-Test

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material :
PHYSICO-CHEMICAL PROPERTIES
- Melting point: 151°C (Rhodia Study, 2008)
- Boiling point: 337.5°C at 1013 hPa (Merck Index)
- Vapour pressure: 0.097 hPa at 18.5°C (Kirk-Othmer)
- Henry's law constant (for volatie substances): 9,656e-9 hPa m³/mol 25°C (Currenta, 2009)
- Water solubility: 23 g/L at 25°C (MITI, 1992)
- Solubility in organic solvents: Adipic acid is not stable in alcohol. The corresponding ester is formed (Beyer, 2004).
- log Pow: 0.093 at pH 3.3 (BASF-Study, 1988)
- pKa: 4.34-5.44 at 18°C; 4.43-5.42 at 20°C; 4.43 at 25°C (Beilstein, 2003)
- Base or acid catalysis of test material:
- UV absorption: t1/2 = 2,9d (Currenta, 2009)

OTHER PROPERTIES
- Adsorption characteristics: adsorption coefficient (Koc) 21.5 (Currenta, 2009)
- Toxicity to microorganisms: Activated sludge, 3-hour EC50 4747 mg/l (Bayer AG, 1988)

Oxygen conditions:

aerobic

Inoculum or test system:

natural water

Details on source and properties of surface water:

surface water of river Main

Duration of test (contact time):

8 d

Initial conc.:

997 mg/L

Based on:

COD

Initial conc.:

345 mg/L

Based on:

DOC

% Degr.:

> 95

Parameter:

DOC removal

Sampling time:

8 d

Transformation products:

not measured

Kinetic of test substance (in %):

ca. 10 after 1 day(s)

ca. 25 after 2 day(s)

ca. 40 after 3 day(s)

ca. 65 after 4 day(s)

> 90 after 7 day(s)

Conclusions:

In a modified Zahn-Wellens test conducted with surface water of the river main 90 percent adipic acid was degraded after 7 days.

Executive summary:

In a modified Zahn-Wellens test conducted with surface water of the river main 90 percent adipic acid was degraded after 7 days.

Description of key information

 Carboxylic acids, di-, C4-6 is considered to be readily biodegradable in surface waters and waste water treatment plants.

Additional information

For the mixture no data on biodegradation in surface water and sediment are available. Adipic acid is applied for read-across approach.

Adipic acid is shown to be biodegradable in surface waters and waste water treatment plants. In a modified Zahn-Wellens-Test, using surface water from the river Main (Germany), 90% of adipic acid was degraded within 8 days (Zahn, 1980).

A waste water treatment simulation test was performed according to a method which is comparable to the OECD guideline 303 A ("Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units). Sludge from a municipal sewage treatment plant was used in this test. After 1 day a DOC removal of 99% was achieved (Gerike, 1979).

As it is shown that all constituents of the mixture are readily biodegradable, it is concluded that succinic acid and glutaric acid are also biodegradable in surface waters and waste water treatment plants.