Registration Dossier

Environmental fate & pathways

Phototransformation in air

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline calculation method
Qualifier:
no guideline required
Principles of method if other than guideline:
Model calculation was performed according to the Atkinson estimation method of the vapour phase reaction rate with hydroxyl radicals (kOH) as proposed by Atkinson in Environmental Toxicology and Chemistry, volume / (1988), pp 435-442
GLP compliance:
no
Remarks:
not applicable

The photochemical oxidative degradation of Diuron in air was determined based on molecular structure and the reaction rate constant with OH radicals (kOH), to be 122.87 x 10-12cm3.molecule-1.sec-1.

Assuming hydroxyl radicals (OH) to be 5 x 105molecules.cm-3, the degradation half-life of Diuron was estimated to be 3.1 hours assuming a moderate OH concentration in the air. A chemical half-life of 4.5 hours is estimated.

The Atmospheric Oxidative Program was also used to determine the half-life in air of Diuron. With a reaction rate constant of 132.16 x 10-12, a half-life of 2.9 hours was calculated.

Executive summary:

In order to determine the atmospheric half-life of Diuron, a calculation based on the Atkinson estimation method was used and the Atmospheric Oxidative Program was also used. A half-life of 2.9 to 3.1 hours was determined indicating a rapid disappearance of Diuron in air.

Description of key information

A half-life of 2.9 to 3.1 h indicates that Diuron will disappear rapidly in air

Key value for chemical safety assessment

Additional information

In order to determine the atmospheric half-life of Diuron, a calculation based on the Atkinson estimation method was used and the Atmospheric Oxidative Program was also used (hellpointner, 1991). A half-life was determined of 2.9 to 3.1 h indicating a rapid disappearance on Diuron in air.