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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

DIDP is readily biodegradable (74% biodegradation in 28 days), and does meet the 10-day window, based on results from a standard OECD ready biodegradation test guideline. The principle transformation products would be mono-isodecyl phthalate (MIDP) and isodecyl alcohol (IDA). Data are available to assess the potential biodegradability of these two transformation products. Biodegradation data are available for a mono ester that is a mixture containing approximately equal amounts of monoesters with normal octyl (n-C8) and normal decyl (n-C10) side chains. Results show that show that this mixture is readily biodegradable and data also show that IDA is readily biodegradable, but does not meet the 10-day window. The n-C8/n-C10 mono ester biodegraded to 94% after 28 days, while IDA biodegraded to 71% after 28 days.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

DIDP has been shown to biodegrade to a high extent in tests of ready and inherent biodegradability using standard OECD test guidelines. DIDP biodegraded 74.0% in 28 days and was readily biodegradable and met the 10-day window (EMBSI, 2009). DIDP also biodegraded to 67.0% in 28 days and was readily biodegradable but did not meet the 10 -day window (EBSI, 1995). Based on the high extent of biodegradability measured using various standard test procedures, DIDP and its degradation products are expected to biodegrade to a high extent under simulated conditions (i.e., wastewater treatment) and in sediment and soil. An additional study withthe monoester of DIDP (mono-isodecyl phthalate, MIDP), which would be one of DIDP's degradation products, showed that MIDP had an average biodegradation half-life of 25 days in marine sediments based on results from two studies.