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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

A shake-flask screening test was designed by Walker, 1984 to rapidly evaluate the relative degradation rates of wide spectrum of chemicals (each compared to methyl patathion). The experimental design for the screening test embodies 4 treatments:
active sediment (AS), sterile sediment (SS), active water (AW), sterile water (SW). Decay curves were produced and rate constant and half life values determined. Nine DBP screens were run involving six geographic sites from Luisiana, Mississippi and Florida.
In AS treatments, the time required for residual DBP to fall below detection limit ranged from 2 to 13 days. In AW this range was from 2 to 17 days. In the formalin-sterilized system, abatement was substantially reduced.
Half-life for active sediment (AS) range from 0.6 d to 10.8 d (average of half-life for AS was 2.96d). Half-life for active water (AW) range from 3.4 d to 17 d (average of half-life for AW was 7.01d).

Key value for chemical safety assessment

Half-life in freshwater:
7.01 d
at the temperature of:
25 °C
Half-life in freshwater sediment:
2.96 d
at the temperature of:
25 °C

Additional information

DBP is biodegradable in natural waters and sediments, with an estimated  half-life in the range of 1 to 17 days (Johnson and Lulves, 1975; Johnson et al, 1984; Walker, 1984; Shelton et al., 1984).