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Environmental fate & pathways

Biodegradation in soil

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Endpoint:
biodegradation in soil: simulation testing
Type of information:
other: published data
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:
Sodium dodecylbenzenesulfonate is one of the linear alkylbenzene sulfonic acids (LAS). Sodium dodecylbenzenesulfonate is regarded with 12C-LAS.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)
GLP compliance:
not specified
Test type:
laboratory
Radiolabelling:
yes
Soil classification:
other: : Soil type in Rapid city is the sandy loam and soil type in Harleysville is the loamy sand.
Details on soil characteristics:
Soils were obtained from sludge-amended agricultural fields in Rapid city and Harleysville. Soil type in Rapid city is the sandy loam and soil type in Harleysville is the loamy sand.
Initial conc.:
250 mg/kg soil d.w.
Based on:
test mat.
Soil No.:
#1
Temp.:
20℃
Humidity:
35% moisture level
Details on experimental conditions:
Tesk flasks were continuously flushed with CO2-free air at >>50ml/min and incubated 20 +/- 2 deg C. Half-lives ofr mineralization(t 1/2) were calculated from the relationship t 1/2=ln2/k1(k1=first-order rate conctant).
DT50:
23.1 d
Type:
(pseudo-)first order (= half-life)
Temp.:
20 °C
Transformation products:
yes
Details on results:
Half-lives for mineralization of the C12-LAS homolog is 23.1 days.
Conclusions:
Half-lives for mineralization of the C12-LAS homolog is 23.1 days.
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
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)
GLP compliance:
not specified
Test type:
laboratory
Radiolabelling:
yes
Oxygen conditions:
aerobic/anaerobic
Soil classification:
other: Alfisol
Details on soil characteristics:
- Soil : Air-dried and sifted to a particle size of 0.125 mmparticle size distribution ; Clay(<2 μm) 17%, silt(2-63 μm) 75%, sand(0.63-2 mm) 8%, organic matter 2.45%- Soil pH : 7.3
Initial conc.:
15 other: μg
Based on:
test mat.
Details on experimental conditions:
- Experience vessels; 1 litre wide-mouth bottles- Incubation mixture; 50g soil and 150ml water were equilibrated for 7 days at 35 deg C in oxygen or nitrogen. Then 15μg of 14C-labelled chemical was added in aqueous solution ot suspension.- Mechnical mixing; continuous shaking in a water bath (35 deg C)
% Degr.:
40.6 - 51.9
Parameter:
CO2 evolution
Sampling time:
42 d
Transformation products:
yes
Conclusions:
n-Dodecylbenzenesulphonate was readily biodegradable. And the degradation (mineralization) values in anaerobic environment was faster than those in aerobic environment.
Endpoint:
biodegradation in soil: simulation testing
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance is readily biodegradable

Description of key information

Biodegradation in soil
 
Ward and Larson (1989) conducted a laboratory study and observed the biodegradation rate constant and half-life for C12-LAS in sludge-amended soil. The biodegradation rate constant for C12-LAS is 0.030 day-1and half-life for C12-LAS is 23.1 days. Scheunertet al., (1987) measured the biomineralization rate of dodecylbenzenesulfonate in soil/water suspension under anaerobic and aerobic conditions for 42 days. The results (40.6%14CO2: aerobic, 51.9%14CO2: anaerobic) showed that the substance was readily biodegradable by the micro-organisms present in soil.

Key value for chemical safety assessment

Half-life in soil:
23.1 d
at the temperature of:
20 °C

Additional information

Biodegradation in soil

 

Ward and Larson (1989) conducted a laboratory study and observed the biodegradation rate constant and half-life for C12-LAS in sludge-amended soil. The biodegradation rate constant for C12-LAS is 0.030 day-1and half-life for C12-LAS is 23.1 days. Scheunertet al., (1987) measured the biomineralization rate of dodecylbenzenesulfonate in soil/water suspension under anaerobic and aerobic conditions for 42 days. The results (40.6%14CO2: aerobic, 51.9%14CO2: anaerobic) showed that the substance was readily biodegradable by the micro-organisms present in soil.

 

Table     Summary of Biodegradationin soil

 

Type/ Method

Test material

Degradation

Duration

References

Aerobic/

Other

C12-LAS

50%

23.1 days

Ward and Larson, 1989

Aerobic and Anaerobic/

Other

Dodecylbenzenesulfonate

40.6%14CO2of mineralization

(aerobic),

51.9%14CO2of mineralization (anaerobic)

42 days

Scheunertet al., 1987