Carboxylic acids, di-, C4-6

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Read-Across from adipic acid, which is a structural analogue and serves well as a representative substance for the carboxylic acid mixture.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

other: US Food and Drug Administration (FDA) Environmental Assessment Technical Assistance Handbook

GLP compliance:

not specified

Test type:

laboratory

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

Soil classification:

other: Nixon sandy loam

Soil no.:

#1

Soil type:

sandy loam

% Clay:

29

% Silt:

21

% Sand:

50

% Org. C:

5

pH:

>= 5.5 - <= 6

Details on soil characteristics:

water-holding capacity: 0.65 g/g of dry soil

Soil No.:

#1

Initial conc.:

1 000 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#1

Temp.:

27 °C

Humidity:

60 other: % of water holding capacity

Soil No.:

#1

% Degr.:

84

Parameter:

CO2 evolution

Sampling time:

30 d

Transformation products:

not specified

1) Cumulative net CO2-evolution during incubation in soil (1000 mg/kg soil; average of three replicates) as percent
conversion of calculated carbon content:
                  day 9:        63%
                  day 20:        76%
                  day 30:        84%

2) Cumulative net CO2 evolution (average of triplicateflasks) as percent conversion of calculated carbon content
at day 22:
                  250 mg/kg dw soil:        78.8%
                  500 mg/kg dw soil:        79.1%
                  1000 mg/kg dw soil:        91.5%
                  2000 mg/kg dw soil:        94.1%

60 % degradation was reached in 1 to 6 d.

Adipic acid is readily biodegradable in soil.

Conclusions:

An 84 % conversion of adipic acid carbon content to carbon dioxide was found after 30 days aerobic incubation in soil.

Executive summary:

An 84 % conversion of adipic acid carbon content to carbon dioxide was found after 30 days aerobic incubation in soil.

60 % degradation was reached in 1 to 6 d. Therefore, adipic acid is readily biodegradable in soil.

Description of key information

Carboxylic acids, di-, C4-6 is considered to be readily biodegradable in soil.

Additional information

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

Biodegradability of adipic acid in soil was assed in a test conducted according to a national standard method of the U. S. Food and Drug Administration (FDA). An 84 % conversion of adipic acid carbon content to carbon dioxide was found after 30 days aerobic incubation in a sandy loam (Sharabi,1993). 60 % degradation was reached in 1 to 6 d.

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 soil.