Registration Dossier

Environmental fate & pathways

Phototransformation in air

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Conclusion (indirect photodegradation): DIUP has the potential to degrade rapidly by OH- attack.  However, multimedia distribution modeling indicates DIUP is predicted to partition negligibly (<0.1%) to the air compartment because it has a low vapor pressure (0.00000050 Pa) and a relatively short atmospheric oxidation half-life (4.2 hours).Therefore, this process is unlikely to contribute significantly to the loss of DIUP from the environment.

Key value for chemical safety assessment

Additional information

Indirect photochemical degradation of DIUP as mediated byhydroxyl radical (OH-) attack is estimated to have a half-life of 0.35 days or 4.2 hours based on a 12-hour sunlight day, a rate of 1.895E-11 cm³/molecule*sec, and an average OH-concentration of 1.5E6 OH-/cm3 (USEPA, 2000). 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.