Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Indirect photochemical degradation of isodecyl benzoate as mediated by OH-attack is estimated to have ahalf-life of 29.75 hours based on a rate of 12.9 E-12 cm3/molecule-sec, and an average OH- concentration of 1.5E6 OH-/cm3. Although isodecyl benzoate has the potential to degrade rapidly byOH-attack, isodecyl benzoate is unlikely to partition to the air compartmentbecause it has a low vapor pressure (0.00845Pa). Although

isodecyl benzoate

has a relatively short atmospheric oxidation half-life (29.75 hours),this process is unlikely to contribute significantly to the loss of

isodecyl benzoate

from the environment.

The HYDROWIN model, a subroutine within the USEPA (2009) computer program, estimates a hydrolysis half-life for isodecyl benzoate of 10.7 years at pH 7 (25°C) and 1.1 years at pH 8 (25°C).

Direct photochemical degradation in water occurs through the absorbance of solar radiation by a chemical substance. If the absorbed energy is high enough, then, in the resultant excited state, the chemical may undergo a transformation. A prerequisite for direct photodegradation is the ability of one or more bonds within a molecule to absorb ultraviolet (UV)/visible light in the 290 to 750 nm range. Light wavelengths longer than 750 nm do not contain sufficient energy to break chemical bonds, and wavelengths below 290 nm are shielded from the earth by the stratospheric ozone layer. An approach to assessing the potential for isodecyl benzoate to undergo direct photochemical degradation is to assume that degradation will occur in proportion to the amount of light wavelengths >290 nm absorbed by isodecyl benzoate molecules. Isodecyl benzoate does not absorb light within a range of 290 to 750 nm. Therefore, direct photolysis will not contribute to the degradation of isodecyl benzoate in the aquatic environment because it does not absorb light at wavelengths in the range that contributes to this process.