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Environmental fate & pathways

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The phototransformation of AAPB consisting of C8-, C10-, C12- , C14- , C16-, and C18-fatty acids was calculated using EPIWIN v3.11, AOPWIN v1.91. Based on a OH radical concentration of 500000 molecules/cm³ (24 h-day, average hydroxyl concentration) and the estimated atmospheric reaction rate constants (C8: 42.769 x 10E-12 cm³/molecule x s; C10: 45.595 x 10E-12 cm³/molecule x s; C12: 48.420 x 10E-12 cm³/molecule x s; C14: 51.247 x 10E-12 cm³/molecule x s; C16: 54.073 x 10E-12 cm³/molecule x s, and C18: 56.899 x 10E-12 cm³/molecule x s) half-lives ranging from 6.8 h (C18 derivate) to 9 h (C8 derivate) were calculated. The results indicate theoretically a rapid photodegradation (t1/2<10 h) of the components (C8 -C18 derivates) of AAPB. Due to the ionic character of the compound and the low vapor pressure, however, the occurrence of gaseous AAPB in air is expected to be negligible and therefore this degradation pathway is only of minor importance.


In accordance with column 2 of REACH Annex VIII, the hydrolysis test does not have to be conducted because AAPB is readily biodegradable. It is shown that biodegradation is the primary route of degradation in the environment.

In addition limited information is available from an EPIWIN calculation. However, there are no details whether the calculation model is validated for the substance under investigation, therefore reliability is not assignable. The stability (hydrolysis) of Coco AAPB was calculated using EPIWIN, HYDROWIN v1.67. Hydrolysis is not to be expected under environmental conditions: the calculated hydrolysis half-life time (t1/2) for Coco AAPB consisting of C8 -C18 fatty acids was found to be > 1 year.