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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

70% after 10 days (readily biodegradable)

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

There are three studies available for Normal-Heptane. The study that shows best the rapid biodegradability of this substance was conducted by Haines and Alexander (1974) using a procedure from the standard methods for the examination of water and waste water. Degradability was assessed by measurement of the biological oxygen demand. In this study Normal-Heptane is reported to biodegrade to 70% after 10 days with an unacclimated sewage sludge inoculum. The other studies using different methods and durations have also shown heptane to biodegrade rapidly. Solano-Serena et al. (1999) investigated the degradation of gasoline by a microflora from urban waste water activated sludge. Unacclimated activated sewage sludge was used as the inoculum. Biodegradation resulted in 60% before day 10. Garnier et al. (2000) investigated the degradation of Normal-Heptane by soil microflora adapted to gasoline in a microcosm. The inoculum was developed using soil obtained and mixed from different contaminated gasoline service stations in Mexico and further enriched in microcosms. Biodegradation reached 100% at day 4. In a further test with an unacclimated inoculum the biodegradation was 23.4% at day 3.