Benzenesulfonic acid, 4-C15-16-sec-alkyl derivs.

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil, other

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

see read-across document

Reason / purpose for cross-reference:

read-across source

Radiolabelling:

no

Key result

% Degr.:

>= 70 - <= 99

Parameter:

test mat. analysis

Sampling time:

122 d

Key result

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 (read across) 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 calculated half life was between 7 and 22 days.

Key value for chemical safety assessment

Half-life in soil:

22 d

Additional information

The disappearance of LAS (read across) 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. 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 were 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 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. 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 breakdown intermediates in soil.