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Environmental fate & pathways

Phototransformation in air

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Description of key information

Rate constant: 0.0000000000262 cm3/molecule*sec
Degradation: 50% after 4.9 hours (0.41 days)

Key value for chemical safety assessment

Additional information

Indirect photochemical degradation of DIDP as mediated by OH- attack is estimated to have a half-life of 0.41 days or 4.9 hours based on a 12 -hour sunlight day, a rate of 2.62E-11 cm3/molecule*sec, and an average OH- concentration of 1.5E6 OH-/cm3. A 12-hour day half-life value normalizes degradation to a standard day light period during which hydroxyl radicals needed for photolysis are generated in the atmosphere. Although DIDP has the potential to degrade rapidly by OH- attack, multimedia distribution modeling indicates DIDP is predicted to partition negligibly (0.1%) to the air compartment because it has a low vapor pressure (0.000051 Pa). Although DIDP has a relatively short atmospheric oxidation half-life (4.9 hours), this process is unlikely to contribute significantly to the loss of DIDP from the environment.