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Environmental fate & pathways

Hydrolysis

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Description of key information

The DT50 values for the degradation of test item were not calculated for pH5, pH 7 and pH 9 because of limited degradation (M-060005-01-1).

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Additional information

One experimental study is available investigating the hydrolysis of the test item according to EPA Guideline N 161-1 (M-060005-01-1). Hydrolysis of the test item at 0.14 mg/L was studied in the dark at 24.9 °C (±0.02 °C) in sterile aqueous buffers at pH 5 (0.01 M sodium acetate), pH 7 (0.01 M tris [(HOCH2)3CNH2]), and pH 9 (0.01 M sodium borate) for 30 d. A preliminary study at 50 °C demonstrated that no volatiles were formed during hydrolysis. Therefore, test vessels were not connected to traps for the collection of CO2 and organic volatiles. Duplicate samples were analyzed at 0, 2, 7, 14, 22, and 30 d. The samples were analyzed directly by HPLC without extraction. The average material balance was 99.8 %, (range = 99.0 to 100.5 %), 100.1 %, (range = 99.3 to 100.6 %), and 100.3 %, (range = 99.8 to 100.7 %) of the applied radioactivity at pH 5, pH 7, and pH 9, respectively. Most of the applied radioactivity was associated with the parent compound at test termination in the pH 5, 7 and 9 buffer solutions. A minor transformation product, unknown A, was formed at a maximum of 1.8 % (day 14; pH 5), 3.0 % (day 22, pH 7), and 1.8 % (day 22, pH 9) of the applied radioactivity. Unknown A was not consistently observed in the study. Another minor transformation product, unknown B, was formed at a maximum of 3.4 % (day 7 and 30; pH 9) of the applied radioactivity. Unknown B remained relatively constant throughout the study. A third minor transformation product, unknown C, was formed at a maximum of 1.5 % (day 30, pH 9) of applied radioactivity. Unknown C was only observed in the day 30 interval of the pH 9 samples. The mean unidentified radioactivity was <1 %, <1 %, and 4.6 % of the applied radioactivity at pH 5, pH 7, and pH 9, respectively (at day 30). The DT50 values for the degradation of test item were not calculated for pH5, pH 7 and pH 9 because of limited degradation.