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Environmental fate & pathways

Phototransformation in air

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Reference
Endpoint:
phototransformation in air
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The applicability domain of the AOPWIN (v.1.92a) modul is not defined finally. Nevertheless, structural fragments of Benzotriazole as well as other chemical substances with compareable molecular weight have been considered in the model. In addition, the group of Benzotriazoles have been explicitly listed in the substances group within range of the model.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Guideline:
other: REACH Guidance on QSARs R.6, May 2008
Principles of method if other than guideline:
AOPWIN estimates the rate constant for the atmospheric, gas-phase reaction between naturally occurring hydroxyl radicals and organic chemicals.
Reference substance:
not specified
DT50:
10.7 d
Test condition:
12-hr day, 1.5E6 OH/cm3, 25 °C
Reaction with:
OH radicals
Rate constant:
0 cm³ molecule-1 d-1
Transformation products:
not specified
Validity criteria fulfilled:
not applicable
Conclusions:
Based on the calculations with AOPWIN 1.92a the half-life of atmospheric 1H-Benzotriazole has been estimated to be about 10.7 days.
Executive summary:

In absence of experimental data a QSAR estimation for the atmospheric phototransformation of 1H-Benzotriazole has been performed by using AOPWIN 1.92a to calculate the gas-phase reaction with natural occurring hydroxyl radicals. The estimation methods of this software have been based primarily on the work of Atkinson and co-workers in 1995. Based on the given conditions a half-life of 10.7 days has been be estimated.

Description of key information

Key values were estimated by AOPwin v1.92.

Key value for chemical safety assessment

Half-life in air:
10.7 d
Degradation rate constant with OH radicals:
0 cm³ molecule-1 d-1

Additional information

Based on the estimation by AOPwin v1.92 the substance is assumed to be degradable by reaction with atmospheric hydroxyl radicals. As this study is not a standard information requirement in REACH and there is no indication from the CSA on the need to further investigate the fate and behaviour of the substance, no further testing is considered necessary.