Glycollic acid

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: The substance was found not to be within the applicability domain of the Atmospheric Oxidation Program v1.90 (AOPWIN) QSAR model and therefore the use of this model to predict atmospheric degradation of the substance cannot be considered valid.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Principles of method if other than guideline:

The calculation (QSAR estimation) was performed using the Atmospheric Oxidation Program v1.90 (AOPWIN). The substance was found not to be within the applicability domain of the Atmospheric Oxidation Program v1.90 (AOPWIN) QSAR model and therefore the use of this model to predict atmospheric degradation of the substance cannot be considered valid.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Glycollic acid

EC Number:

201-180-5

EC Name:

Glycollic acid

Cas Number:

79-14-1

Molecular formula:

C2H4O3

IUPAC Name:

2-hydroxyacetic acid

Study design

Estimation method (if used):

The photochemical oxidative degradation half-life of glycolic acid in air was estimated using the Atmospheric Oxidation Program v1.90 (AOPWIN), which is based on the structural activity relationship (QSAR's) methods developed by Atkinson, R (1985 to 1996).

Details on light source:

not applicable

Details on test conditions:

not applicable

Results and discussion

Preliminary study:

not applicable

Dissipation half-life of parent compound

DT50:

41.247 h

Test condition:

The substance was found not to be within the applicability domain of the Atmospheric Oxidation Program v1.90 (AOPWIN) QSAR model and therefore the use of this model to predict atmospheric degradation of the substance cannot be considered valid.

Any other information on results incl. tables

The half life and rate constant for the photochemical oxidative degradation of glycolic acid in air via the hydroxyl reaction was estimated to be 41.247 hours and 3.11 x 10^–12 cm³ molecule^-1 s^-1, respectively (based on 1.5 x 10⁶ OH radicals per cm³) resulting mostly from hydrogen abstraction.

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Remarks:

The substance was found not to be within the applicability domain of the Atmospheric Oxidation Program v1.90 (AOPWIN) QSAR model and therefore the use of this model to predict atmospheric degradation of the substance cannot be considered valid.

Conclusions:

Due to the chemical lifetime of glycolic acid in the air (at the most 3.4 days, based on a 12 hour day) it is to be expected that the active substance can not be transported in the gaseous phase over large distances and can not accumulate in the air.

Executive summary:

The photochemical oxidative degradation half-life of glycolic acid in air was estimated using the Atmospheric Oxidation Program v1.90 (AOPWIN), which is based on the structural activity relationship (QSAR's) methods developed by Atkinson, R (1985 to 1996).

The half life and rate constant for the photochemical oxidative degradation of glycolic acid in air via the hydroxyl reaction was estimated to be 41.247 hours and 3.11 x 10^–12cm³molecule^-1s^-1, respectively (based on 1.5 x 10⁶OH radicals per cm³) resulting mostly from hydrogen abstraction. On the account of the chemical lifetime of glycolic acid in the air (at the most 3.4 days, based on a 12 hour day) it is to be expected that the active substance can not be transported in the gaseous phase over large distances and can not accumulate in the air. Thus, no difference in the behaviour between glycolic acid and other organic substances emitted into the air from natural sources (e.g. plants, soil) is indicated.

Due to the chemical lifetime of glycolic acid in the air (at the most 3.4 days, based on a 12 hour day) it is to be expected that the active substance can not be transported in the gaseous phase over large distances and can not accumulate in the air.