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

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil, other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The studies are very well documented in this peer-reviewed publication.

Justification for type of information:

Category Approach; test material is reference substance LAS. LAS provides suitable read across for LAB Sulfonic Acids as both form the identical chemical species in aqueous solutions at neutral (environmental) pH, namely, the LAS ion (C10-13 linear alkyl benzene-SO3-) and would be expected to have similar biodegradation properties.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The disappearance of LAS from sludge-amended soils was investigated from 51 fields on 24 farms in the Thames Water Authority, U.K. Annual sludge spreading averaged 6 ton/ha. Application of sludge was made by subsurface injection, surface spreading onto arable land with or without ploughing, or surface spreading onto pasture land. Regular sampling was conducted for up to 122 days. LAS concentrations in the soil were analyzed with HPLC.

GLP compliance:

not specified

Test type:

field trial

Radiolabelling:

no

Oxygen conditions:

not specified

Soil classification:

not specified

Details on soil characteristics:

51 fields on 24 farms in the Thames Water Authority, U.K. Annual sludge spreading averaged 6 ton/ha. Application of sludge was made by subsurface injection, surface spreading onto arable land with or without ploughing, or surface spreading onto pasture land.

Duration:

<= 122 d

DT50:

> 7 - < 22 d

Type:

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

Remarks on result:

other: Temperature not given

Transformation products:

not specified

Evaporation of parent compound:

not specified

Volatile metabolites:

not specified

Residues:

not specified

Details on results:

In fields not recently spread with sludge, the concentrations of LAS found in the sludge amended soil were generally less than 1 mg/kg. This represents an estimated loss of LAS from soil of >98%. In fields recently spread, the concentrations in soil are in the range of <0.2 to 20 mg/kg, representing losses of LAS between 70 and 99% of the estimated total cumulative load. The identity of the degradation products was not analyzed.

Half-lives compare well with those for ultimate degradation in lab soil tests (with 14-C-evolution), indicating that the degradation of LAS does not lead to the formation of significant levels of break-down intermediates in soil.

Conclusions:

The authors conclude that overall the data indicate that an adequate safety margin exists between the concentrations of LAS in sludge-amended soils and those likely to affect the growth of crop plants.

Executive summary:

The disappearance of LAS from sludge-amended soils was investigated from 51 fields on 24 farms in the Thames Water Authority. Sludge was applied by subsurface injection, or surface spreading. Sampling was conducted for up to 122 days. In fields not recently spread with sludge, the concentrations of LAS found in the sludge amended soil were generally less than 1 mg/kg.  In fields recently spread, the concentrations in soil are in the range of 0.2 to 20 mg/kg, representing losses of LAS between 70 and 99% of the estimated total cumulative load. 

Description of key information

The disappearance of LAS from sludge-amended soils was investigated from 51 fields on 24 farms in the Thames Water Authority (United Kingdom). Sludge was applied by subsurface injection or surface spreading. Sampling was conducted for up to 122 days. The disappearance of LAS from sludge-amended soils was reported as having a Half-life = between 7 and 22 days.