Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs., ammonium salts

Biodegradation in soil

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in soil: simulation testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Refer to Section 13.2 for read-across justification document.

Reason / purpose for cross-reference:

read-across source

Soil No.:

#1

% Recovery:

89.1

St. dev.:

1.7

Soil No.:

#2

% Recovery:

89.1

St. dev.:

6.7

Soil No.:

#3

% Recovery:

88.4

St. dev.:

2.4

Soil No.:

#1

% Degr.:

61.8

St. dev.:

0.83

Parameter:

CO2 evolution

Sampling time:

2 mo

Soil No.:

#2

% Degr.:

67.1

St. dev.:

3.41

Parameter:

CO2 evolution

Sampling time:

2 mo

Soil No.:

#3

% Degr.:

64.4

St. dev.:

1.08

Parameter:

CO2 evolution

Sampling time:

2 mo

Soil No.:

#1

DT50:

8.2 d

St. dev.:

0.15

Type:

(pseudo-)first order (= half-life)

Temp.:

15 °C

Soil No.:

#2

DT50:

7.9 d

St. dev.:

0.14

Type:

(pseudo-)first order (= half-life)

Temp.:

15 °C

Soil No.:

#3

DT50:

7.5 d

St. dev.:

0.2

Type:

(pseudo-)first order (= half-life)

Temp.:

15 °C

Transformation products:

not specified

Conclusions:

In a radiolabelled soil degradation study, the DT50 of of the test item was determined to be 7.5 - 8.2 days when tested in 3 soil types. The study was conducted in a manner similar to OECD 307 (aerobic) and is considered suitable for chemical safety assessment purposes.

Executive summary:

In a one-to-one read-across approach, the substance benzenesulfonic acid, 4-C10-13-sec-alkyl derivs. (data on LAS-Na salt as part of category approach) is considered appropriate for direct read-across (one-to-one) to benzenesulfonic acid, 4-C10-13-sec-alkyl derivs., ammonium salts (target substance) for the endpoint biodegradation in soil.

The mineralization of 14C-labeled linear alkylbenzene sulfonate (LAS) was investigated in 3 different soil types (coarse sand, sand and clay), using a method similar to OECD 307. Chemical-soil complexes were prepared 24 h before the experiments were started. Each chemical was dissolved in an organic solvent and was added to individual subsamples of soil (1.3 mg/kg dry st). Stock solutions of LAS were prepared in methanol. After the addition of a volume of the stock solution to the subsamples of soil, the solvent was allowed to evaporate for approximately 30 min at room temperature while flushing the spiked soil with N2. After evaporation of the solvent, the chemicals were allowed to sorb to the sludge for 24 h at 4 °C under an N2 atmosphere in order to minimize biodegradation.

Soils were moistened to 40 % of the water holding capacity (WHC), 6g wet weight quantities were transferred into glass tubes (internal diameter, 12 mm length, 50 mm) and were gently pressed into a core of approximately 25 mm.  Each tube was placed in a 200-ml glass jar with a gas phase of atmospheric air. A wet filter paper was placed in each jar to minimize the water loss from the mixtures, and the jars were closed with a gas-tight lid. A glass vial containing 2 ml of 0.5 N potassium hydroxide (KOH) was placed in each jar to trap the evolved 14CO2. The jars were opened for approximately 10 min once or twice a week to restore the oxygen content of the headspace. All experiments were carried out in the dark at 15 °C in four replicates and had a duration of two months.

The DT50 of the test item was determined to be 7.5 - 8.2 days.

Reference 2

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Well documented study published in relevant journal

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Refer to Section 13.2 for read-across justification document.

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

Soil classification:

not specified

Soil no.:

#1

Soil type:

other: Coarse, sandy

% Clay:

3.9

% Silt:

4.1

% Sand:

89

% Org. C:

3

pH:

6

Soil no.:

#2

Soil type:

sand

% Clay:

4.3

% Silt:

3.8

% Sand:

89.7

% Org. C:

2.2

pH:

6.1

Soil no.:

#3

Soil type:

clay

% Clay:

10.6

% Silt:

11.8

% Sand:

74.6

% Org. C:

3

pH:

6.6

Details on soil characteristics:

The soils used in the biodegradation experiments were a coarse, sandy soil collected from the upper 20 cm of an agricultural field in Jyndevad, Denmark, a sandy soil from Lundgaard (Denmark) and a more clayey soil from Askov (Denmark). None of the soils had previously received sludge. All soils were air dried at room temperature for 20 h, sieved through a 2-mm mesh, and stored at 4 °C until use.

Soil No.:

#1

Duration:

2 mo

Soil No.:

#2

Duration:

2 mo

Soil No.:

#3

Duration:

2 mo

Soil No.:

#1

Initial conc.:

1.3 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#2

Initial conc.:

1.3 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#3

Initial conc.:

1.3 mg/kg soil d.w.

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Soil No.:

#1

Temp.:

15 °C

Humidity:

Not reported

Microbial biomass:

Not reported

Soil No.:

#2

Temp.:

15 °C

Humidity:

Not reported

Microbial biomass:

Not reported

Soil No.:

#3

Temp.:

15 °C

Humidity:

Not reported

Microbial biomass:

Not reported

Details on experimental conditions:

Chemical-soil complexes were prepared 24 h before the experiments were started. Each chemical was dissolved in an organic solvent and was added to individual subsamples of soil. Stock solutions of LAS were prepared in methanol. After the addition of a volume of the stock solution to the subsamples of soil, the solvent was allowed to evaporate for approximately 30 min at room temperature while flushing the spiked soil with N2. After evaporation of the solvent, the chemicals were allowed to sorb to the sludge for 24 h at 4 °C under an N2 atmosphere in order to minimize biodegradation.
Soils were moistened to 40 % of the water holding capacity (WHC), 6g wet weight quantities were transferred into glass tubes (internal diameter, 12 mm length, 50 mm) and were gently pressed into a core of approximately 25 mm. Each tube was placed in a 200-ml glass jar with a gas phase of atmospheric air. A wet filter paper was placed in each jar to minimize the water loss from the mixtures, and the jars were closed with a gas-tight lid. A glass vial containing 2 ml of 0.5 N potassium hydroxide (KOH) was placed in each jar to trap the evolved 14CO2. The jars were opened for approximately 10 min once or twice a week to restore the oxygen content of the headspace. All experiments were carried out in the dark at 15 °C in four replicates and had a duration of two months.

Soil No.:

#1

% Recovery:

89.1

St. dev.:

1.7

Soil No.:

#2

% Recovery:

89.1

St. dev.:

6.7

Soil No.:

#3

% Recovery:

88.4

St. dev.:

2.4

Soil No.:

#1

% Degr.:

61.8

St. dev.:

0.83

Parameter:

CO2 evolution

Sampling time:

2 mo

Soil No.:

#2

% Degr.:

67.1

St. dev.:

3.41

Parameter:

CO2 evolution

Sampling time:

2 mo

Soil No.:

#3

% Degr.:

64.4

St. dev.:

1.08

Parameter:

CO2 evolution

Sampling time:

2 mo

Soil No.:

#1

DT50:

8.2 d

St. dev.:

0.15

Type:

(pseudo-)first order (= half-life)

Temp.:

15 °C

Soil No.:

#2

DT50:

7.9 d

St. dev.:

0.14

Type:

(pseudo-)first order (= half-life)

Temp.:

15 °C

Soil No.:

#3

DT50:

7.5 d

St. dev.:

0.2

Type:

(pseudo-)first order (= half-life)

Temp.:

15 °C

Transformation products:

not specified

Evaporation of parent compound:

not specified

Volatile metabolites:

not specified

Residues:

yes

Conclusions:

In a radiolabelled soil degradation study, the DT50 of LAS was determined to be 7.5 - 8.2 days when tested in 3 soil types. The study was conducted in a manner similar to OECD 307 (aerobic) and is considered suitable for chemical safety assessment purposes.

Executive summary:

The mineralization of 14C-labeled linear alkylbenzene sulfonate (LAS) was investigated in 3 different soil types (coarse sand, sand and clay), using a method similar to OECD 307. Chemical-soil complexes were prepared 24 h before the experiments were started. Each chemical was dissolved in an organic solvent and was added to individual subsamples of soil (1.3 mg/kg dry st). Stock solutions of LAS were prepared in methanol. After the addition of a volume of the stock solution to the subsamples of soil, the solvent was allowed to evaporate for approximately 30 min at room temperature while flushing the spiked soil with N2. After evaporation of the solvent, the chemicals were allowed to sorb to the sludge for 24 h at 4 °C under an N2 atmosphere in order to minimize biodegradation.

Soils were moistened to 40 % of the water holding capacity (WHC), 6g wet weight quantities were transferred into glass tubes (internal diameter, 12 mm length, 50 mm) and were gently pressed into a core of approximately 25 mm.  Each tube was placed in a 200-ml glass jar with a gas phase of atmospheric air. A wet filter paper was placed in each jar to minimize the water loss from the mixtures, and the jars were closed with a gas-tight lid. A glass vial containing 2 ml of 0.5 N potassium hydroxide (KOH) was placed in each jar to trap the evolved 14CO2. The jars were opened for approximately 10 min once or twice a week to restore the oxygen content of the headspace. All experiments were carried out in the dark at 15 °C in four replicates and had a duration of two months.

The DT50 of LAS was determined to be 7.5 - 8.2 days.

Description of key information

DT50 Soil = 7.5 - 8.2 days (3 soils); OECD 307 (similar); Gejlsberg et al., 2001 (read across to benzenesulfonic acid, 4-C10-13-sec-alkyl derivs. - data on LAS-Na salt as part of category approach)

Key value for chemical safety assessment

Half-life in soil:

8.2 d

at the temperature of:

15 °C

Additional information

In a one-to-one read-across approach, the substance benzenesulfonic acid, 4-C10-13-sec-alkyl derivs. (data on LAS-Na salt as part of category approach) is considered appropriate for direct read-across (one-to-one) to benzenesulfonic acid, 4-C10-13-sec-alkyl derivs., ammonium salts (target substance) for the endpoint biodegradation in soil.

The mineralization of 14C-labeled linear alkylbenzene sulfonate (LAS) was investigated in 3 different soil types (coarse sand, sand and clay), using a method similar to OECD 307. Chemical-soil complexes were prepared 24 h before the experiments were started. Each chemical was dissolved in an organic solvent and was added to individual subsamples of soil (1.3 mg/kg dry st). Stock solutions of LAS were prepared in methanol. After the addition of a volume of the stock solution to the subsamples of soil, the solvent was allowed to evaporate for approximately 30 min at room temperature while flushing the spiked soil with N2. After evaporation of the solvent, the chemicals were allowed to sorb to the sludge for 24 h at 4 °C under an N2 atmosphere in order to minimize biodegradation.

Soils were moistened to 40 % of the water holding capacity (WHC), 6g wet weight quantities were transferred into glass tubes (internal diameter, 12 mm length, 50 mm) and were gently pressed into a core of approximately 25 mm.  Each tube was placed in a 200-ml glass jar with a gas phase of atmospheric air. A wet filter paper was placed in each jar to minimize the water loss from the mixtures, and the jars were closed with a gas-tight lid. A glass vial containing 2 ml of 0.5 N potassium hydroxide (KOH) was placed in each jar to trap the evolved 14CO2. The jars were opened for approximately 10 min once or twice a week to restore the oxygen content of the headspace. All experiments were carried out in the dark at 15 °C in four replicates and had a duration of two months.

The DT50 of the test item was determined to be 7.5 - 8.2 days.