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Environmental fate & pathways

Biodegradation in soil

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Description of key information

Key value for chemical safety assessment

Half-life in soil:
7.2 h
at the temperature of:
20 °C

Additional information

A study was conducted to determine the biodegradanility of the substance according to US EPA Guideline 162 -1. The study was undertaken before the more all-encompassing guidelines were developed within OECD/Europe, therefore it is appropriate to assess for validity against these guidelines as being relevant at the time of undertaking the test. Under the study conditions, BIT degrades rapidly (DT50 < 1 day) to BIT-S-oxide (oxidation)

BIT-S-oxide is rapidly transformed to Saccharin (oxidation). Saccharin is transformed to o-sulphobenzamide (hydrolysis), which is then, via an unspecified route, incorporated into the biomass or transformed to CO2. Based on the study results, it is reasonable to assume that as a worst case, the DT90 of BIT is 24 hours (in reality, no BIT remained after 24 hours). Therefore, assuming first order kinetics, the DT50 is equivalent to DT90/3.32.

Therefore;

DT50: 7.2 hours

DT90: 24 hours

Rate constant = ln2/DT50 = 2.3 d-1 (Powell and Roberts, 1989)